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TOMOYO Linux Cross Reference
Linux/lib/Kconfig.debug

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Diff markup

Differences between /lib/Kconfig.debug (Version linux-6.11.5) and /lib/Kconfig.debug (Version linux-5.0.21)


  1 # SPDX-License-Identifier: GPL-2.0-only        << 
  2 menu "Kernel hacking"                               1 menu "Kernel hacking"
  3                                                     2 
  4 menu "printk and dmesg options"                     3 menu "printk and dmesg options"
  5                                                     4 
  6 config PRINTK_TIME                                  5 config PRINTK_TIME
  7         bool "Show timing information on print      6         bool "Show timing information on printks"
  8         depends on PRINTK                           7         depends on PRINTK
  9         help                                        8         help
 10           Selecting this option causes time st      9           Selecting this option causes time stamps of the printk()
 11           messages to be added to the output o     10           messages to be added to the output of the syslog() system
 12           call and at the console.                 11           call and at the console.
 13                                                    12 
 14           The timestamp is always recorded int     13           The timestamp is always recorded internally, and exported
 15           to /dev/kmsg. This flag just specifi     14           to /dev/kmsg. This flag just specifies if the timestamp should
 16           be included, not that the timestamp      15           be included, not that the timestamp is recorded.
 17                                                    16 
 18           The behavior is also controlled by t     17           The behavior is also controlled by the kernel command line
 19           parameter printk.time=1. See Documen     18           parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
 20                                                    19 
 21 config PRINTK_CALLER                           << 
 22         bool "Show caller information on print << 
 23         depends on PRINTK                      << 
 24         help                                   << 
 25           Selecting this option causes printk( << 
 26           in task context) or a caller "proces << 
 27           to every message.                    << 
 28                                                << 
 29           This option is intended for environm << 
 30           concurrently call printk() for many  << 
 31           interpret without knowing where thes << 
 32           line which was divided into multiple << 
 33                                                << 
 34           Since toggling after boot makes the  << 
 35           no option to enable/disable at the k << 
 36           sysfs interface.                     << 
 37                                                << 
 38 config STACKTRACE_BUILD_ID                     << 
 39         bool "Show build ID information in sta << 
 40         depends on PRINTK                      << 
 41         help                                   << 
 42           Selecting this option adds build ID  << 
 43           stacktraces printed with the printk  << 
 44                                                << 
 45           This option is intended for distros  << 
 46           accessible but can be downloaded giv << 
 47           kernel module where the function is  << 
 48                                                << 
 49 config CONSOLE_LOGLEVEL_DEFAULT                    20 config CONSOLE_LOGLEVEL_DEFAULT
 50         int "Default console loglevel (1-15)"      21         int "Default console loglevel (1-15)"
 51         range 1 15                                 22         range 1 15
 52         default "7"                                23         default "7"
 53         help                                       24         help
 54           Default loglevel to determine what w     25           Default loglevel to determine what will be printed on the console.
 55                                                    26 
 56           Setting a default here is equivalent     27           Setting a default here is equivalent to passing in loglevel=<x> in
 57           the kernel bootargs. loglevel=<x> co     28           the kernel bootargs. loglevel=<x> continues to override whatever
 58           value is specified here as well.         29           value is specified here as well.
 59                                                    30 
 60           Note: This does not affect the log l     31           Note: This does not affect the log level of un-prefixed printk()
 61           usage in the kernel. That is control     32           usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
 62           option.                                  33           option.
 63                                                    34 
 64 config CONSOLE_LOGLEVEL_QUIET                      35 config CONSOLE_LOGLEVEL_QUIET
 65         int "quiet console loglevel (1-15)"        36         int "quiet console loglevel (1-15)"
 66         range 1 15                                 37         range 1 15
 67         default "4"                                38         default "4"
 68         help                                       39         help
 69           loglevel to use when "quiet" is pass     40           loglevel to use when "quiet" is passed on the kernel commandline.
 70                                                    41 
 71           When "quiet" is passed on the kernel     42           When "quiet" is passed on the kernel commandline this loglevel
 72           will be used as the loglevel. IOW pa     43           will be used as the loglevel. IOW passing "quiet" will be the
 73           equivalent of passing "loglevel=<CON     44           equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
 74                                                    45 
 75 config MESSAGE_LOGLEVEL_DEFAULT                    46 config MESSAGE_LOGLEVEL_DEFAULT
 76         int "Default message log level (1-7)"      47         int "Default message log level (1-7)"
 77         range 1 7                                  48         range 1 7
 78         default "4"                                49         default "4"
 79         help                                       50         help
 80           Default log level for printk stateme     51           Default log level for printk statements with no specified priority.
 81                                                    52 
 82           This was hard-coded to KERN_WARNING      53           This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
 83           that are auditing their logs closely     54           that are auditing their logs closely may want to set it to a lower
 84           priority.                                55           priority.
 85                                                    56 
 86           Note: This does not affect what mess     57           Note: This does not affect what message level gets printed on the console
 87           by default. To change that, use logl     58           by default. To change that, use loglevel=<x> in the kernel bootargs,
 88           or pick a different CONSOLE_LOGLEVEL     59           or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
 89                                                    60 
 90 config BOOT_PRINTK_DELAY                           61 config BOOT_PRINTK_DELAY
 91         bool "Delay each boot printk message b     62         bool "Delay each boot printk message by N milliseconds"
 92         depends on DEBUG_KERNEL && PRINTK && G     63         depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
 93         help                                       64         help
 94           This build option allows you to read     65           This build option allows you to read kernel boot messages
 95           by inserting a short delay after eac     66           by inserting a short delay after each one.  The delay is
 96           specified in milliseconds on the ker     67           specified in milliseconds on the kernel command line,
 97           using "boot_delay=N".                    68           using "boot_delay=N".
 98                                                    69 
 99           It is likely that you would also nee     70           It is likely that you would also need to use "lpj=M" to preset
100           the "loops per jiffie" value.            71           the "loops per jiffie" value.
101           See a previous boot log for the "lpj     72           See a previous boot log for the "lpj" value to use for your
102           system, and then set "lpj=M" before      73           system, and then set "lpj=M" before setting "boot_delay=N".
103           NOTE:  Using this option may adverse     74           NOTE:  Using this option may adversely affect SMP systems.
104           I.e., processors other than the firs     75           I.e., processors other than the first one may not boot up.
105           BOOT_PRINTK_DELAY also may cause LOC     76           BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106           what it believes to be lockup condit     77           what it believes to be lockup conditions.
107                                                    78 
108 config DYNAMIC_DEBUG                               79 config DYNAMIC_DEBUG
109         bool "Enable dynamic printk() support"     80         bool "Enable dynamic printk() support"
110         default n                                  81         default n
111         depends on PRINTK                          82         depends on PRINTK
112         depends on (DEBUG_FS || PROC_FS)       !!  83         depends on DEBUG_FS
113         select DYNAMIC_DEBUG_CORE              << 
114         help                                       84         help
115                                                    85 
116           Compiles debug level messages into t     86           Compiles debug level messages into the kernel, which would not
117           otherwise be available at runtime. T     87           otherwise be available at runtime. These messages can then be
118           enabled/disabled based on various le     88           enabled/disabled based on various levels of scope - per source file,
119           function, module, format string, and     89           function, module, format string, and line number. This mechanism
120           implicitly compiles in all pr_debug(     90           implicitly compiles in all pr_debug() and dev_dbg() calls, which
121           enlarges the kernel text size by abo     91           enlarges the kernel text size by about 2%.
122                                                    92 
123           If a source file is compiled with DE     93           If a source file is compiled with DEBUG flag set, any
124           pr_debug() calls in it are enabled b     94           pr_debug() calls in it are enabled by default, but can be
125           disabled at runtime as below.  Note      95           disabled at runtime as below.  Note that DEBUG flag is
126           turned on by many CONFIG_*DEBUG* opt     96           turned on by many CONFIG_*DEBUG* options.
127                                                    97 
128           Usage:                                   98           Usage:
129                                                    99 
130           Dynamic debugging is controlled via     100           Dynamic debugging is controlled via the 'dynamic_debug/control' file,
131           which is contained in the 'debugfs'  !! 101           which is contained in the 'debugfs' filesystem. Thus, the debugfs
132           Thus, the debugfs or procfs filesyst !! 102           filesystem must first be mounted before making use of this feature.
133           making use of this feature.          << 
134           We refer the control file as: <debug    103           We refer the control file as: <debugfs>/dynamic_debug/control. This
135           file contains a list of the debug st    104           file contains a list of the debug statements that can be enabled. The
136           format for each line of the file is:    105           format for each line of the file is:
137                                                   106 
138                 filename:lineno [module]functi    107                 filename:lineno [module]function flags format
139                                                   108 
140           filename : source file of the debug     109           filename : source file of the debug statement
141           lineno : line number of the debug st    110           lineno : line number of the debug statement
142           module : module that contains the de    111           module : module that contains the debug statement
143           function : function that contains th    112           function : function that contains the debug statement
144           flags : '=p' means the line is turne !! 113           flags : '=p' means the line is turned 'on' for printing
145           format : the format used for the deb !! 114           format : the format used for the debug statement
146                                                   115 
147           From a live system:                     116           From a live system:
148                                                   117 
149                 nullarbor:~ # cat <debugfs>/dy    118                 nullarbor:~ # cat <debugfs>/dynamic_debug/control
150                 # filename:lineno [module]func    119                 # filename:lineno [module]function flags format
151                 fs/aio.c:222 [aio]__put_ioctx     120                 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152                 fs/aio.c:248 [aio]ioctx_alloc     121                 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153                 fs/aio.c:1770 [aio]sys_io_canc    122                 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154                                                   123 
155           Example usage:                          124           Example usage:
156                                                   125 
157                 // enable the message at line     126                 // enable the message at line 1603 of file svcsock.c
158                 nullarbor:~ # echo -n 'file sv    127                 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159                                                   128                                                 <debugfs>/dynamic_debug/control
160                                                   129 
161                 // enable all the messages in     130                 // enable all the messages in file svcsock.c
162                 nullarbor:~ # echo -n 'file sv    131                 nullarbor:~ # echo -n 'file svcsock.c +p' >
163                                                   132                                                 <debugfs>/dynamic_debug/control
164                                                   133 
165                 // enable all the messages in     134                 // enable all the messages in the NFS server module
166                 nullarbor:~ # echo -n 'module     135                 nullarbor:~ # echo -n 'module nfsd +p' >
167                                                   136                                                 <debugfs>/dynamic_debug/control
168                                                   137 
169                 // enable all 12 messages in t    138                 // enable all 12 messages in the function svc_process()
170                 nullarbor:~ # echo -n 'func sv    139                 nullarbor:~ # echo -n 'func svc_process +p' >
171                                                   140                                                 <debugfs>/dynamic_debug/control
172                                                   141 
173                 // disable all 12 messages in     142                 // disable all 12 messages in the function svc_process()
174                 nullarbor:~ # echo -n 'func sv    143                 nullarbor:~ # echo -n 'func svc_process -p' >
175                                                   144                                                 <debugfs>/dynamic_debug/control
176                                                   145 
177           See Documentation/admin-guide/dynami    146           See Documentation/admin-guide/dynamic-debug-howto.rst for additional
178           information.                            147           information.
179                                                   148 
180 config DYNAMIC_DEBUG_CORE                      << 
181         bool "Enable core function of dynamic  << 
182         depends on PRINTK                      << 
183         depends on (DEBUG_FS || PROC_FS)       << 
184         help                                   << 
185           Enable core functional support of dy << 
186           when you want to tie dynamic debug t << 
187           DYNAMIC_DEBUG_MODULE defined for eac << 
188           the case of embedded system where th << 
189           sensitive for people.                << 
190                                                << 
191 config SYMBOLIC_ERRNAME                        << 
192         bool "Support symbolic error names in  << 
193         default y if PRINTK                    << 
194         help                                   << 
195           If you say Y here, the kernel's prin << 
196           be able to print symbolic error name << 
197           of the number 28. It makes the kerne << 
198           (about 3KB), but can make the kernel << 
199                                                << 
200 config DEBUG_BUGVERBOSE                        << 
201         bool "Verbose BUG() reporting (adds 70 << 
202         depends on BUG && (GENERIC_BUG || HAVE << 
203         default y                              << 
204         help                                   << 
205           Say Y here to make BUG() panics outp << 
206           of the BUG call as well as the EIP a << 
207           debugging but costs about 70-100K of << 
208                                                << 
209 endmenu # "printk and dmesg options"              149 endmenu # "printk and dmesg options"
210                                                   150 
211 config DEBUG_KERNEL                            << 
212         bool "Kernel debugging"                << 
213         help                                   << 
214           Say Y here if you are developing dri << 
215           identify kernel problems.            << 
216                                                << 
217 config DEBUG_MISC                              << 
218         bool "Miscellaneous debug code"        << 
219         default DEBUG_KERNEL                   << 
220         depends on DEBUG_KERNEL                << 
221         help                                   << 
222           Say Y here if you need to enable mis << 
223           be under a more specific debug optio << 
224                                                << 
225 menu "Compile-time checks and compiler options    151 menu "Compile-time checks and compiler options"
226                                                   152 
227 config DEBUG_INFO                                 153 config DEBUG_INFO
228         bool                                   !! 154         bool "Compile the kernel with debug info"
229         help                                   !! 155         depends on DEBUG_KERNEL && !COMPILE_TEST
230           A kernel debug info option other tha << 
231           in the "Debug information" choice be << 
232           information will be generated for bu << 
233                                                << 
234 # Clang generates .uleb128 with label differen << 
235 # older binutils ports do not support when uti << 
236 # relaxation: https://sourceware.org/bugzilla/ << 
237 config AS_HAS_NON_CONST_ULEB128                << 
238         def_bool $(as-instr,.uleb128 .Lexpr_en << 
239                                                << 
240 choice                                         << 
241         prompt "Debug information"             << 
242         depends on DEBUG_KERNEL                << 
243         help                                      156         help
244           Selecting something other than "None !! 157           If you say Y here the resulting kernel image will include
245           that will include debugging info res !! 158           debugging info resulting in a larger kernel image.
246           This adds debug symbols to the kerne    159           This adds debug symbols to the kernel and modules (gcc -g), and
247           is needed if you intend to use kerne    160           is needed if you intend to use kernel crashdump or binary object
248           tools like crash, kgdb, LKCD, gdb, e    161           tools like crash, kgdb, LKCD, gdb, etc on the kernel.
                                                   >> 162           Say Y here only if you plan to debug the kernel.
249                                                   163 
250           Choose which version of DWARF debug  !! 164           If unsure, say N.
251           select "Toolchain default".          << 
252                                                << 
253 config DEBUG_INFO_NONE                         << 
254         bool "Disable debug information"       << 
255         help                                   << 
256           Do not build the kernel with debuggi << 
257           result in a faster and smaller build << 
258                                                << 
259 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT      << 
260         bool "Rely on the toolchain's implicit << 
261         select DEBUG_INFO                      << 
262         depends on !CC_IS_CLANG || AS_IS_LLVM  << 
263         help                                   << 
264           The implicit default version of DWAR << 
265           toolchain changes over time.         << 
266                                                << 
267           This can break consumers of the debu << 
268           support newer revisions, and prevent << 
269           those should be less common scenario << 
270                                                << 
271 config DEBUG_INFO_DWARF4                       << 
272         bool "Generate DWARF Version 4 debugin << 
273         select DEBUG_INFO                      << 
274         depends on !CC_IS_CLANG || AS_IS_LLVM  << 
275         help                                   << 
276           Generate DWARF v4 debug info. This r << 
277           if using clang without clang's integ << 
278                                                << 
279           If you have consumers of DWARF debug << 
280           newer revisions of DWARF, you may wi << 
281           config select this.                  << 
282                                                << 
283 config DEBUG_INFO_DWARF5                       << 
284         bool "Generate DWARF Version 5 debugin << 
285         select DEBUG_INFO                      << 
286         depends on !ARCH_HAS_BROKEN_DWARF5     << 
287         depends on !CC_IS_CLANG || AS_IS_LLVM  << 
288         help                                   << 
289           Generate DWARF v5 debug info. Requir << 
290           5.0+ accepts the -gdwarf-5 flag but  << 
291           draft features until 7.0), and gdb 8 << 
292                                                << 
293           Changes to the structure of debug in << 
294           15-18% savings in resulting image an << 
295           compared to DWARF Version 4. DWARF V << 
296           extensions such as accelerators for  << 
297           for fission (.dwo/.dwp) files. Users << 
298           config if they rely on tooling that  << 
299           support DWARF Version 5.             << 
300                                                << 
301 endchoice # "Debug information"                << 
302                                                << 
303 if DEBUG_INFO                                  << 
304                                                   165 
305 config DEBUG_INFO_REDUCED                         166 config DEBUG_INFO_REDUCED
306         bool "Reduce debugging information"       167         bool "Reduce debugging information"
                                                   >> 168         depends on DEBUG_INFO
307         help                                      169         help
308           If you say Y here gcc is instructed     170           If you say Y here gcc is instructed to generate less debugging
309           information for structure types. Thi    171           information for structure types. This means that tools that
310           need full debugging information (lik    172           need full debugging information (like kgdb or systemtap) won't
311           be happy. But if you merely need deb    173           be happy. But if you merely need debugging information to
312           resolve line numbers there is no los    174           resolve line numbers there is no loss. Advantage is that
313           build directory object sizes shrink     175           build directory object sizes shrink dramatically over a full
314           DEBUG_INFO build and compile times a    176           DEBUG_INFO build and compile times are reduced too.
315           Only works with newer gcc versions.     177           Only works with newer gcc versions.
316                                                   178 
317 choice                                         << 
318         prompt "Compressed Debug information"  << 
319         help                                   << 
320           Compress the resulting debug info. R << 
321           but requires that consumers are able << 
322                                                << 
323           If unsure, choose DEBUG_INFO_COMPRES << 
324                                                << 
325 config DEBUG_INFO_COMPRESSED_NONE              << 
326         bool "Don't compress debug information << 
327         help                                   << 
328           Don't compress debug info sections.  << 
329                                                << 
330 config DEBUG_INFO_COMPRESSED_ZLIB              << 
331         bool "Compress debugging information w << 
332         depends on $(cc-option,-gz=zlib)       << 
333         depends on $(ld-option,--compress-debu << 
334         help                                   << 
335           Compress the debug information using << 
336           5.0+, binutils 2.26+, and zlib.      << 
337                                                << 
338           Users of dpkg-deb via scripts/packag << 
339           size of their debug .deb packages wi << 
340           debug info being compressed with zli << 
341           recompressed with a different compre << 
342           preferable to setting $KDEB_COMPRESS << 
343           larger.                              << 
344                                                << 
345 config DEBUG_INFO_COMPRESSED_ZSTD              << 
346         bool "Compress debugging information w << 
347         depends on $(cc-option,-gz=zstd)       << 
348         depends on $(ld-option,--compress-debu << 
349         help                                   << 
350           Compress the debug information using << 
351           compression than zlib, for about the << 
352           toolchain support.  Requires GCC 13. << 
353           zstd.                                << 
354                                                << 
355 endchoice # "Compressed Debug information"     << 
356                                                << 
357 config DEBUG_INFO_SPLIT                           179 config DEBUG_INFO_SPLIT
358         bool "Produce split debuginfo in .dwo     180         bool "Produce split debuginfo in .dwo files"
359         depends on $(cc-option,-gsplit-dwarf)  !! 181         depends on DEBUG_INFO
360         # RISC-V linker relaxation + -gsplit-d << 
361         # prior to 12.x:                       << 
362         # https://github.com/llvm/llvm-project << 
363         # https://gcc.gnu.org/bugzilla/show_bu << 
364         depends on !RISCV || GCC_VERSION >= 12 << 
365         help                                      182         help
366           Generate debug info into separate .d    183           Generate debug info into separate .dwo files. This significantly
367           reduces the build directory size for    184           reduces the build directory size for builds with DEBUG_INFO,
368           because it stores the information on    185           because it stores the information only once on disk in .dwo
369           files instead of multiple times in o    186           files instead of multiple times in object files and executables.
370           In addition the debug information is    187           In addition the debug information is also compressed.
371                                                   188 
372           Requires recent gcc (4.7+) and recen    189           Requires recent gcc (4.7+) and recent gdb/binutils.
373           Any tool that packages or reads debu    190           Any tool that packages or reads debug information would need
374           to know about the .dwo files and inc    191           to know about the .dwo files and include them.
375           Incompatible with older versions of     192           Incompatible with older versions of ccache.
376                                                   193 
377 config DEBUG_INFO_BTF                          !! 194 config DEBUG_INFO_DWARF4
378         bool "Generate BTF type information"   !! 195         bool "Generate dwarf4 debuginfo"
379         depends on !DEBUG_INFO_SPLIT && !DEBUG !! 196         depends on DEBUG_INFO
380         depends on !GCC_PLUGIN_RANDSTRUCT || C << 
381         depends on BPF_SYSCALL                 << 
382         depends on !DEBUG_INFO_DWARF5 || PAHOL << 
383         # pahole uses elfutils, which does not << 
384         depends on !HEXAGON                    << 
385         help                                   << 
386           Generate deduplicated BTF type infor << 
387           Turning this on expects presence of  << 
388           DWARF type info into equivalent dedu << 
389                                                << 
390 config PAHOLE_HAS_SPLIT_BTF                    << 
391         def_bool PAHOLE_VERSION >= 119         << 
392                                                << 
393 config PAHOLE_HAS_BTF_TAG                      << 
394         def_bool PAHOLE_VERSION >= 123         << 
395         depends on CC_IS_CLANG                 << 
396         help                                   << 
397           Decide whether pahole emits btf_tag  << 
398           btf_decl_tag) or not. Currently only << 
399           these attributes, so make the config << 
400                                                << 
401 config PAHOLE_HAS_LANG_EXCLUDE                 << 
402         def_bool PAHOLE_VERSION >= 124         << 
403         help                                   << 
404           Support for the --lang_exclude flag  << 
405           compilation units from the supplied  << 
406           omit Rust CUs which are not supporte << 
407           otherwise it would emit malformed ke << 
408           using DEBUG_INFO_BTF_MODULES.        << 
409                                                << 
410 config DEBUG_INFO_BTF_MODULES                  << 
411         bool "Generate BTF type information fo << 
412         default y                              << 
413         depends on DEBUG_INFO_BTF && MODULES & << 
414         help                                      197         help
415           Generate compact split BTF type info !! 198           Generate dwarf4 debug info. This requires recent versions
416                                                !! 199           of gcc and gdb. It makes the debug information larger.
417 config MODULE_ALLOW_BTF_MISMATCH               !! 200           But it significantly improves the success of resolving
418         bool "Allow loading modules with non-m !! 201           variables in gdb on optimized code.
419         depends on DEBUG_INFO_BTF_MODULES      << 
420         help                                   << 
421           For modules whose split BTF does not << 
422           BTF rather than refusing to load. Th << 
423           module BTF enabled is to reject modu << 
424           this option will still load module B << 
425           it when a mismatch is found.         << 
426                                                   202 
427 config GDB_SCRIPTS                                203 config GDB_SCRIPTS
428         bool "Provide GDB scripts for kernel d    204         bool "Provide GDB scripts for kernel debugging"
                                                   >> 205         depends on DEBUG_INFO
429         help                                      206         help
430           This creates the required links to G    207           This creates the required links to GDB helper scripts in the
431           build directory. If you load vmlinux    208           build directory. If you load vmlinux into gdb, the helper
432           scripts will be automatically import    209           scripts will be automatically imported by gdb as well, and
433           additional functions are available t    210           additional functions are available to analyze a Linux kernel
434           instance. See Documentation/dev-tool    211           instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
435           for further details.                    212           for further details.
436                                                   213 
437 endif # DEBUG_INFO                             !! 214 config ENABLE_MUST_CHECK
                                                   >> 215         bool "Enable __must_check logic"
                                                   >> 216         default y
                                                   >> 217         help
                                                   >> 218           Enable the __must_check logic in the kernel build.  Disable this to
                                                   >> 219           suppress the "warning: ignoring return value of 'foo', declared with
                                                   >> 220           attribute warn_unused_result" messages.
438                                                   221 
439 config FRAME_WARN                                 222 config FRAME_WARN
440         int "Warn for stack frames larger than !! 223         int "Warn for stack frames larger than (needs gcc 4.4)"
441         range 0 8192                              224         range 0 8192
442         default 0 if KMSAN                     !! 225         default 3072 if KASAN_EXTRA
443         default 2048 if GCC_PLUGIN_LATENT_ENTR    226         default 2048 if GCC_PLUGIN_LATENT_ENTROPY
444         default 2048 if PARISC                 !! 227         default 1280 if (!64BIT && PARISC)
445         default 1536 if (!64BIT && XTENSA)     !! 228         default 1024 if (!64BIT && !PARISC)
446         default 1280 if KASAN && !64BIT        << 
447         default 1024 if !64BIT                 << 
448         default 2048 if 64BIT                     229         default 2048 if 64BIT
449         help                                      230         help
450           Tell the compiler to warn at build t !! 231           Tell gcc to warn at build time for stack frames larger than this.
451           Setting this too low will cause a lo    232           Setting this too low will cause a lot of warnings.
452           Setting it to 0 disables the warning    233           Setting it to 0 disables the warning.
                                                   >> 234           Requires gcc 4.4
453                                                   235 
454 config STRIP_ASM_SYMS                             236 config STRIP_ASM_SYMS
455         bool "Strip assembler-generated symbol    237         bool "Strip assembler-generated symbols during link"
456         default n                                 238         default n
457         help                                      239         help
458           Strip internal assembler-generated s    240           Strip internal assembler-generated symbols during a link (symbols
459           that look like '.Lxxx') so they don'    241           that look like '.Lxxx') so they don't pollute the output of
460           get_wchan() and suchlike.               242           get_wchan() and suchlike.
461                                                   243 
462 config READABLE_ASM                               244 config READABLE_ASM
463         bool "Generate readable assembler code !! 245         bool "Generate readable assembler code"
464         depends on DEBUG_KERNEL                !! 246         depends on DEBUG_KERNEL
465         depends on CC_IS_GCC                   !! 247         help
                                                   >> 248           Disable some compiler optimizations that tend to generate human unreadable
                                                   >> 249           assembler output. This may make the kernel slightly slower, but it helps
                                                   >> 250           to keep kernel developers who have to stare a lot at assembler listings
                                                   >> 251           sane.
                                                   >> 252 
                                                   >> 253 config UNUSED_SYMBOLS
                                                   >> 254         bool "Enable unused/obsolete exported symbols"
                                                   >> 255         default y if X86
                                                   >> 256         help
                                                   >> 257           Unused but exported symbols make the kernel needlessly bigger.  For
                                                   >> 258           that reason most of these unused exports will soon be removed.  This
                                                   >> 259           option is provided temporarily to provide a transition period in case
                                                   >> 260           some external kernel module needs one of these symbols anyway. If you
                                                   >> 261           encounter such a case in your module, consider if you are actually
                                                   >> 262           using the right API.  (rationale: since nobody in the kernel is using
                                                   >> 263           this in a module, there is a pretty good chance it's actually the
                                                   >> 264           wrong interface to use).  If you really need the symbol, please send a
                                                   >> 265           mail to the linux kernel mailing list mentioning the symbol and why
                                                   >> 266           you really need it, and what the merge plan to the mainline kernel for
                                                   >> 267           your module is.
                                                   >> 268 
                                                   >> 269 config PAGE_OWNER
                                                   >> 270         bool "Track page owner"
                                                   >> 271         depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
                                                   >> 272         select DEBUG_FS
                                                   >> 273         select STACKTRACE
                                                   >> 274         select STACKDEPOT
                                                   >> 275         select PAGE_EXTENSION
466         help                                      276         help
467           Disable some compiler optimizations  !! 277           This keeps track of what call chain is the owner of a page, may
468           assembler output. This may make the  !! 278           help to find bare alloc_page(s) leaks. Even if you include this
469           to keep kernel developers who have t !! 279           feature on your build, it is disabled in default. You should pass
470           sane.                                !! 280           "page_owner=on" to boot parameter in order to enable it. Eats
                                                   >> 281           a fair amount of memory if enabled. See tools/vm/page_owner_sort.c
                                                   >> 282           for user-space helper.
471                                                   283 
472 config HEADERS_INSTALL                         !! 284           If unsure, say N.
473         bool "Install uapi headers to usr/incl !! 285 
                                                   >> 286 config DEBUG_FS
                                                   >> 287         bool "Debug Filesystem"
                                                   >> 288         help
                                                   >> 289           debugfs is a virtual file system that kernel developers use to put
                                                   >> 290           debugging files into.  Enable this option to be able to read and
                                                   >> 291           write to these files.
                                                   >> 292 
                                                   >> 293           For detailed documentation on the debugfs API, see
                                                   >> 294           Documentation/filesystems/.
                                                   >> 295 
                                                   >> 296           If unsure, say N.
                                                   >> 297 
                                                   >> 298 config HEADERS_CHECK
                                                   >> 299         bool "Run 'make headers_check' when building vmlinux"
474         depends on !UML                           300         depends on !UML
475         help                                      301         help
476           This option will install uapi header !! 302           This option will extract the user-visible kernel headers whenever
477           into the usr/include directory for u !! 303           building the kernel, and will run basic sanity checks on them to
478           This is unneeded for building the ke !! 304           ensure that exported files do not attempt to include files which
479           user-space program samples. It is al !! 305           were not exported, etc.
480           as uapi header sanity checks.        !! 306 
                                                   >> 307           If you're making modifications to header files which are
                                                   >> 308           relevant for userspace, say 'Y', and check the headers
                                                   >> 309           exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
                                                   >> 310           your build tree), to make sure they're suitable.
481                                                   311 
482 config DEBUG_SECTION_MISMATCH                     312 config DEBUG_SECTION_MISMATCH
483         bool "Enable full Section mismatch ana    313         bool "Enable full Section mismatch analysis"
484         depends on CC_IS_GCC                   << 
485         help                                      314         help
486           The section mismatch analysis checks    315           The section mismatch analysis checks if there are illegal
487           references from one section to anoth    316           references from one section to another section.
488           During linktime or runtime, some sec    317           During linktime or runtime, some sections are dropped;
489           any use of code/data previously in t    318           any use of code/data previously in these sections would
490           most likely result in an oops.          319           most likely result in an oops.
491           In the code, functions and variables    320           In the code, functions and variables are annotated with
492           __init,, etc. (see the full list in     321           __init,, etc. (see the full list in include/linux/init.h),
493           which results in the code/data being    322           which results in the code/data being placed in specific sections.
494           The section mismatch analysis is alw    323           The section mismatch analysis is always performed after a full
495           kernel build, and enabling this opti    324           kernel build, and enabling this option causes the following
496           additional step to occur:            !! 325           additional steps to occur:
497           - Add the option -fno-inline-functio    326           - Add the option -fno-inline-functions-called-once to gcc commands.
498             When inlining a function annotated    327             When inlining a function annotated with __init in a non-init
499             function, we would lose the sectio    328             function, we would lose the section information and thus
500             the analysis would not catch the i    329             the analysis would not catch the illegal reference.
501             This option tells gcc to inline le    330             This option tells gcc to inline less (but it does result in
502             a larger kernel).                     331             a larger kernel).
                                                   >> 332           - Run the section mismatch analysis for each module/built-in.a file.
                                                   >> 333             When we run the section mismatch analysis on vmlinux.o, we
                                                   >> 334             lose valuable information about where the mismatch was
                                                   >> 335             introduced.
                                                   >> 336             Running the analysis for each module/built-in.a file
                                                   >> 337             tells where the mismatch happens much closer to the
                                                   >> 338             source. The drawback is that the same mismatch is
                                                   >> 339             reported at least twice.
                                                   >> 340           - Enable verbose reporting from modpost in order to help resolve
                                                   >> 341             the section mismatches that are reported.
503                                                   342 
504 config SECTION_MISMATCH_WARN_ONLY                 343 config SECTION_MISMATCH_WARN_ONLY
505         bool "Make section mismatch errors non    344         bool "Make section mismatch errors non-fatal"
506         default y                                 345         default y
507         help                                      346         help
508           If you say N here, the build process    347           If you say N here, the build process will fail if there are any
509           section mismatch, instead of just th    348           section mismatch, instead of just throwing warnings.
510                                                   349 
511           If unsure, say Y.                       350           If unsure, say Y.
512                                                   351 
513 config DEBUG_FORCE_FUNCTION_ALIGN_64B          << 
514         bool "Force all function address 64B a << 
515         depends on EXPERT && (X86_64 || ARM64  << 
516         select FUNCTION_ALIGNMENT_64B          << 
517         help                                   << 
518           There are cases that a commit from o << 
519           address alignment of other domains,  << 
520           bump (regression or improvement). En << 
521           verify if the bump is caused by func << 
522           it will slightly increase the kernel << 
523                                                << 
524           It is mainly for debug and performan << 
525                                                << 
526 #                                                 352 #
527 # Select this config option from the architect    353 # Select this config option from the architecture Kconfig, if it
528 # is preferred to always offer frame pointers     354 # is preferred to always offer frame pointers as a config
529 # option on the architecture (regardless of KE    355 # option on the architecture (regardless of KERNEL_DEBUG):
530 #                                                 356 #
531 config ARCH_WANT_FRAME_POINTERS                   357 config ARCH_WANT_FRAME_POINTERS
532         bool                                      358         bool
533                                                   359 
534 config FRAME_POINTER                              360 config FRAME_POINTER
535         bool "Compile the kernel with frame po    361         bool "Compile the kernel with frame pointers"
536         depends on DEBUG_KERNEL && (M68K || UM    362         depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
537         default y if (DEBUG_INFO && UML) || AR    363         default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
538         help                                      364         help
539           If you say Y here the resulting kern    365           If you say Y here the resulting kernel image will be slightly
540           larger and slower, but it gives very    366           larger and slower, but it gives very useful debugging information
541           in case of kernel bugs. (precise oop    367           in case of kernel bugs. (precise oopses/stacktraces/warnings)
542                                                   368 
543 config OBJTOOL                                 << 
544         bool                                   << 
545                                                << 
546 config STACK_VALIDATION                           369 config STACK_VALIDATION
547         bool "Compile-time stack metadata vali    370         bool "Compile-time stack metadata validation"
548         depends on HAVE_STACK_VALIDATION && UN !! 371         depends on HAVE_STACK_VALIDATION
549         select OBJTOOL                         << 
550         default n                                 372         default n
551         help                                      373         help
552           Validate frame pointer rules at comp !! 374           Add compile-time checks to validate stack metadata, including frame
553           runtime stack traces are more reliab !! 375           pointers (if CONFIG_FRAME_POINTER is enabled).  This helps ensure
                                                   >> 376           that runtime stack traces are more reliable.
554                                                   377 
555           For more information, see            !! 378           This is also a prerequisite for generation of ORC unwind data, which
556           tools/objtool/Documentation/objtool. !! 379           is needed for CONFIG_UNWINDER_ORC.
557                                                   380 
558 config NOINSTR_VALIDATION                      !! 381           For more information, see
559         bool                                   !! 382           tools/objtool/Documentation/stack-validation.txt.
560         depends on HAVE_NOINSTR_VALIDATION &&  << 
561         select OBJTOOL                         << 
562         default y                              << 
563                                                << 
564 config VMLINUX_MAP                             << 
565         bool "Generate vmlinux.map file when l << 
566         depends on EXPERT                      << 
567         help                                   << 
568           Selecting this option will pass "-Ma << 
569           when linking vmlinux. That file can  << 
570           and debugging magic section games, a << 
571           pieces of code get eliminated with   << 
572           CONFIG_LD_DEAD_CODE_DATA_ELIMINATION << 
573                                                   383 
574 config DEBUG_FORCE_WEAK_PER_CPU                   384 config DEBUG_FORCE_WEAK_PER_CPU
575         bool "Force weak per-cpu definitions"     385         bool "Force weak per-cpu definitions"
576         depends on DEBUG_KERNEL                   386         depends on DEBUG_KERNEL
577         help                                      387         help
578           s390 and alpha require percpu variab    388           s390 and alpha require percpu variables in modules to be
579           defined weak to work around addressi    389           defined weak to work around addressing range issue which
580           puts the following two restrictions     390           puts the following two restrictions on percpu variable
581           definitions.                            391           definitions.
582                                                   392 
583           1. percpu symbols must be unique whe    393           1. percpu symbols must be unique whether static or not
584           2. percpu variables can't be defined    394           2. percpu variables can't be defined inside a function
585                                                   395 
586           To ensure that generic code follows     396           To ensure that generic code follows the above rules, this
587           option forces all percpu variables t    397           option forces all percpu variables to be defined as weak.
588                                                   398 
589 endmenu # "Compiler options"                      399 endmenu # "Compiler options"
590                                                   400 
591 menu "Generic Kernel Debugging Instruments"    << 
592                                                << 
593 config MAGIC_SYSRQ                                401 config MAGIC_SYSRQ
594         bool "Magic SysRq key"                    402         bool "Magic SysRq key"
595         depends on !UML                           403         depends on !UML
596         help                                      404         help
597           If you say Y here, you will have som    405           If you say Y here, you will have some control over the system even
598           if the system crashes for example du    406           if the system crashes for example during kernel debugging (e.g., you
599           will be able to flush the buffer cac    407           will be able to flush the buffer cache to disk, reboot the system
600           immediately or dump some status info    408           immediately or dump some status information). This is accomplished
601           by pressing various keys while holdi    409           by pressing various keys while holding SysRq (Alt+PrintScreen). It
602           also works on a serial console (on P    410           also works on a serial console (on PC hardware at least), if you
603           send a BREAK and then within 5 secon    411           send a BREAK and then within 5 seconds a command keypress. The
604           keys are documented in <file:Documen    412           keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
605           Don't say Y unless you really know w    413           Don't say Y unless you really know what this hack does.
606                                                   414 
607 config MAGIC_SYSRQ_DEFAULT_ENABLE                 415 config MAGIC_SYSRQ_DEFAULT_ENABLE
608         hex "Enable magic SysRq key functions     416         hex "Enable magic SysRq key functions by default"
609         depends on MAGIC_SYSRQ                    417         depends on MAGIC_SYSRQ
610         default 0x1                               418         default 0x1
611         help                                      419         help
612           Specifies which SysRq key functions     420           Specifies which SysRq key functions are enabled by default.
613           This may be set to 1 or 0 to enable     421           This may be set to 1 or 0 to enable or disable them all, or
614           to a bitmask as described in Documen    422           to a bitmask as described in Documentation/admin-guide/sysrq.rst.
615                                                   423 
616 config MAGIC_SYSRQ_SERIAL                         424 config MAGIC_SYSRQ_SERIAL
617         bool "Enable magic SysRq key over seri    425         bool "Enable magic SysRq key over serial"
618         depends on MAGIC_SYSRQ                    426         depends on MAGIC_SYSRQ
619         default y                                 427         default y
620         help                                      428         help
621           Many embedded boards have a disconne    429           Many embedded boards have a disconnected TTL level serial which can
622           generate some garbage that can lead     430           generate some garbage that can lead to spurious false sysrq detects.
623           This option allows you to decide whe    431           This option allows you to decide whether you want to enable the
624           magic SysRq key.                        432           magic SysRq key.
625                                                   433 
626 config MAGIC_SYSRQ_SERIAL_SEQUENCE             !! 434 config DEBUG_KERNEL
627         string "Char sequence that enables mag !! 435         bool "Kernel debugging"
628         depends on MAGIC_SYSRQ_SERIAL          << 
629         default ""                             << 
630         help                                   << 
631           Specifies a sequence of characters t << 
632           SysRq on a serial console.           << 
633                                                << 
634           If unsure, leave an empty string and << 
635                                                << 
636 config DEBUG_FS                                << 
637         bool "Debug Filesystem"                << 
638         help                                   << 
639           debugfs is a virtual file system tha << 
640           debugging files into.  Enable this o << 
641           write to these files.                << 
642                                                << 
643           For detailed documentation on the de << 
644           Documentation/filesystems/.          << 
645                                                << 
646           If unsure, say N.                    << 
647                                                << 
648 choice                                         << 
649         prompt "Debugfs default access"        << 
650         depends on DEBUG_FS                    << 
651         default DEBUG_FS_ALLOW_ALL             << 
652         help                                   << 
653           This selects the default access rest << 
654           It can be overridden with kernel com << 
655           debugfs=[on,no-mount,off]. The restr << 
656           and filesystem registration.         << 
657                                                << 
658 config DEBUG_FS_ALLOW_ALL                      << 
659         bool "Access normal"                   << 
660         help                                   << 
661           No restrictions apply. Both API and  << 
662           is on. This is the normal default op << 
663                                                << 
664 config DEBUG_FS_DISALLOW_MOUNT                 << 
665         bool "Do not register debugfs as files << 
666         help                                   << 
667           The API is open but filesystem is no << 
668           their work and read with debug tools << 
669           debugfs filesystem.                  << 
670                                                << 
671 config DEBUG_FS_ALLOW_NONE                     << 
672         bool "No access"                       << 
673         help                                      436         help
674           Access is off. Clients get -PERM whe !! 437           Say Y here if you are developing drivers or trying to debug and
675           debugfs tree and debugfs is not regi !! 438           identify kernel problems.
676           Client can then back-off or continue << 
677                                                << 
678 endchoice                                      << 
679                                                << 
680 source "lib/Kconfig.kgdb"                      << 
681 source "lib/Kconfig.ubsan"                     << 
682 source "lib/Kconfig.kcsan"                     << 
683                                                << 
684 endmenu                                        << 
685                                                << 
686 menu "Networking Debugging"                    << 
687                                                << 
688 source "net/Kconfig.debug"                     << 
689                                                << 
690 endmenu # "Networking Debugging"               << 
691                                                   439 
692 menu "Memory Debugging"                           440 menu "Memory Debugging"
693                                                   441 
694 source "mm/Kconfig.debug"                         442 source "mm/Kconfig.debug"
695                                                   443 
696 config DEBUG_OBJECTS                              444 config DEBUG_OBJECTS
697         bool "Debug object operations"            445         bool "Debug object operations"
698         depends on DEBUG_KERNEL                   446         depends on DEBUG_KERNEL
699         help                                      447         help
700           If you say Y here, additional code w    448           If you say Y here, additional code will be inserted into the
701           kernel to track the life time of var    449           kernel to track the life time of various objects and validate
702           the operations on those objects.        450           the operations on those objects.
703                                                   451 
704 config DEBUG_OBJECTS_SELFTEST                     452 config DEBUG_OBJECTS_SELFTEST
705         bool "Debug objects selftest"             453         bool "Debug objects selftest"
706         depends on DEBUG_OBJECTS                  454         depends on DEBUG_OBJECTS
707         help                                      455         help
708           This enables the selftest of the obj    456           This enables the selftest of the object debug code.
709                                                   457 
710 config DEBUG_OBJECTS_FREE                         458 config DEBUG_OBJECTS_FREE
711         bool "Debug objects in freed memory"      459         bool "Debug objects in freed memory"
712         depends on DEBUG_OBJECTS                  460         depends on DEBUG_OBJECTS
713         help                                      461         help
714           This enables checks whether a k/v fr    462           This enables checks whether a k/v free operation frees an area
715           which contains an object which has n    463           which contains an object which has not been deactivated
716           properly. This can make kmalloc/kfre    464           properly. This can make kmalloc/kfree-intensive workloads
717           much slower.                            465           much slower.
718                                                   466 
719 config DEBUG_OBJECTS_TIMERS                       467 config DEBUG_OBJECTS_TIMERS
720         bool "Debug timer objects"                468         bool "Debug timer objects"
721         depends on DEBUG_OBJECTS                  469         depends on DEBUG_OBJECTS
722         help                                      470         help
723           If you say Y here, additional code w    471           If you say Y here, additional code will be inserted into the
724           timer routines to track the life tim    472           timer routines to track the life time of timer objects and
725           validate the timer operations.          473           validate the timer operations.
726                                                   474 
727 config DEBUG_OBJECTS_WORK                         475 config DEBUG_OBJECTS_WORK
728         bool "Debug work objects"                 476         bool "Debug work objects"
729         depends on DEBUG_OBJECTS                  477         depends on DEBUG_OBJECTS
730         help                                      478         help
731           If you say Y here, additional code w    479           If you say Y here, additional code will be inserted into the
732           work queue routines to track the lif    480           work queue routines to track the life time of work objects and
733           validate the work operations.           481           validate the work operations.
734                                                   482 
735 config DEBUG_OBJECTS_RCU_HEAD                     483 config DEBUG_OBJECTS_RCU_HEAD
736         bool "Debug RCU callbacks objects"        484         bool "Debug RCU callbacks objects"
737         depends on DEBUG_OBJECTS                  485         depends on DEBUG_OBJECTS
738         help                                      486         help
739           Enable this to turn on debugging of     487           Enable this to turn on debugging of RCU list heads (call_rcu() usage).
740                                                   488 
741 config DEBUG_OBJECTS_PERCPU_COUNTER               489 config DEBUG_OBJECTS_PERCPU_COUNTER
742         bool "Debug percpu counter objects"       490         bool "Debug percpu counter objects"
743         depends on DEBUG_OBJECTS                  491         depends on DEBUG_OBJECTS
744         help                                      492         help
745           If you say Y here, additional code w    493           If you say Y here, additional code will be inserted into the
746           percpu counter routines to track the    494           percpu counter routines to track the life time of percpu counter
747           objects and validate the percpu coun    495           objects and validate the percpu counter operations.
748                                                   496 
749 config DEBUG_OBJECTS_ENABLE_DEFAULT               497 config DEBUG_OBJECTS_ENABLE_DEFAULT
750         int "debug_objects bootup default valu    498         int "debug_objects bootup default value (0-1)"
751         range 0 1                              !! 499         range 0 1
752         default "1"                            !! 500         default "1"
753         depends on DEBUG_OBJECTS               !! 501         depends on DEBUG_OBJECTS
                                                   >> 502         help
                                                   >> 503           Debug objects boot parameter default value
                                                   >> 504 
                                                   >> 505 config DEBUG_SLAB
                                                   >> 506         bool "Debug slab memory allocations"
                                                   >> 507         depends on DEBUG_KERNEL && SLAB
                                                   >> 508         help
                                                   >> 509           Say Y here to have the kernel do limited verification on memory
                                                   >> 510           allocation as well as poisoning memory on free to catch use of freed
                                                   >> 511           memory. This can make kmalloc/kfree-intensive workloads much slower.
                                                   >> 512 
                                                   >> 513 config DEBUG_SLAB_LEAK
                                                   >> 514         bool "Memory leak debugging"
                                                   >> 515         depends on DEBUG_SLAB
                                                   >> 516 
                                                   >> 517 config SLUB_DEBUG_ON
                                                   >> 518         bool "SLUB debugging on by default"
                                                   >> 519         depends on SLUB && SLUB_DEBUG
                                                   >> 520         default n
                                                   >> 521         help
                                                   >> 522           Boot with debugging on by default. SLUB boots by default with
                                                   >> 523           the runtime debug capabilities switched off. Enabling this is
                                                   >> 524           equivalent to specifying the "slub_debug" parameter on boot.
                                                   >> 525           There is no support for more fine grained debug control like
                                                   >> 526           possible with slub_debug=xxx. SLUB debugging may be switched
                                                   >> 527           off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
                                                   >> 528           "slub_debug=-".
                                                   >> 529 
                                                   >> 530 config SLUB_STATS
                                                   >> 531         default n
                                                   >> 532         bool "Enable SLUB performance statistics"
                                                   >> 533         depends on SLUB && SYSFS
                                                   >> 534         help
                                                   >> 535           SLUB statistics are useful to debug SLUBs allocation behavior in
                                                   >> 536           order find ways to optimize the allocator. This should never be
                                                   >> 537           enabled for production use since keeping statistics slows down
                                                   >> 538           the allocator by a few percentage points. The slabinfo command
                                                   >> 539           supports the determination of the most active slabs to figure
                                                   >> 540           out which slabs are relevant to a particular load.
                                                   >> 541           Try running: slabinfo -DA
                                                   >> 542 
                                                   >> 543 config HAVE_DEBUG_KMEMLEAK
                                                   >> 544         bool
                                                   >> 545 
                                                   >> 546 config DEBUG_KMEMLEAK
                                                   >> 547         bool "Kernel memory leak detector"
                                                   >> 548         depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
                                                   >> 549         select DEBUG_FS
                                                   >> 550         select STACKTRACE if STACKTRACE_SUPPORT
                                                   >> 551         select KALLSYMS
                                                   >> 552         select CRC32
754         help                                      553         help
755           Debug objects boot parameter default !! 554           Say Y here if you want to enable the memory leak
                                                   >> 555           detector. The memory allocation/freeing is traced in a way
                                                   >> 556           similar to the Boehm's conservative garbage collector, the
                                                   >> 557           difference being that the orphan objects are not freed but
                                                   >> 558           only shown in /sys/kernel/debug/kmemleak. Enabling this
                                                   >> 559           feature will introduce an overhead to memory
                                                   >> 560           allocations. See Documentation/dev-tools/kmemleak.rst for more
                                                   >> 561           details.
756                                                   562 
757 config SHRINKER_DEBUG                          !! 563           Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
758         bool "Enable shrinker debugging suppor !! 564           of finding leaks due to the slab objects poisoning.
759         depends on DEBUG_FS                    !! 565 
                                                   >> 566           In order to access the kmemleak file, debugfs needs to be
                                                   >> 567           mounted (usually at /sys/kernel/debug).
                                                   >> 568 
                                                   >> 569 config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
                                                   >> 570         int "Maximum kmemleak early log entries"
                                                   >> 571         depends on DEBUG_KMEMLEAK
                                                   >> 572         range 200 40000
                                                   >> 573         default 400
760         help                                      574         help
761           Say Y to enable the shrinker debugfs !! 575           Kmemleak must track all the memory allocations to avoid
762           visibility into the kernel memory sh !! 576           reporting false positives. Since memory may be allocated or
763           Disable it to avoid an extra memory  !! 577           freed before kmemleak is initialised, an early log buffer is
                                                   >> 578           used to store these actions. If kmemleak reports "early log
                                                   >> 579           buffer exceeded", please increase this value.
764                                                   580 
765 config DEBUG_STACK_USAGE                       !! 581 config DEBUG_KMEMLEAK_TEST
766         bool "Stack utilization instrumentatio !! 582         tristate "Simple test for the kernel memory leak detector"
767         depends on DEBUG_KERNEL                !! 583         depends on DEBUG_KMEMLEAK && m
768         help                                      584         help
769           Enables the display of the minimum a !! 585           This option enables a module that explicitly leaks memory.
770           task has ever had available in the s << 
771           Also emits a message to dmesg when a << 
772           used more stack space than previousl << 
773                                                   586 
774           This option will slow down process c !! 587           If unsure, say N.
775                                                   588 
776 config SCHED_STACK_END_CHECK                   !! 589 config DEBUG_KMEMLEAK_DEFAULT_OFF
777         bool "Detect stack corruption on calls !! 590         bool "Default kmemleak to off"
778         depends on DEBUG_KERNEL                !! 591         depends on DEBUG_KMEMLEAK
779         default n                              << 
780         help                                      592         help
781           This option checks for a stack overr !! 593           Say Y here to disable kmemleak by default. It can then be enabled
782           If the stack end location is found t !! 594           on the command line via kmemleak=on.
783           the content of the corrupted region  << 
784           This is to ensure no erroneous behav << 
785           data corruption or a sporadic crash  << 
786           is examined. The runtime overhead in << 
787                                                   595 
788 config ARCH_HAS_DEBUG_VM_PGTABLE               !! 596 config DEBUG_KMEMLEAK_AUTO_SCAN
789         bool                                   !! 597         bool "Enable kmemleak auto scan thread on boot up"
                                                   >> 598         default y
                                                   >> 599         depends on DEBUG_KMEMLEAK
790         help                                      600         help
791           An architecture should select this w !! 601           Depending on the cpu, kmemleak scan may be cpu intensive and can
792           build and run DEBUG_VM_PGTABLE.      !! 602           stall user tasks at times. This option enables/disables automatic
                                                   >> 603           kmemleak scan at boot up.
                                                   >> 604 
                                                   >> 605           Say N here to disable kmemleak auto scan thread to stop automatic
                                                   >> 606           scanning. Disabling this option disables automatic reporting of
                                                   >> 607           memory leaks.
793                                                   608 
794 config DEBUG_VM_IRQSOFF                        !! 609           If unsure, say Y.
795         def_bool DEBUG_VM && !PREEMPT_RT       !! 610 
                                                   >> 611 config DEBUG_STACK_USAGE
                                                   >> 612         bool "Stack utilization instrumentation"
                                                   >> 613         depends on DEBUG_KERNEL && !IA64
                                                   >> 614         help
                                                   >> 615           Enables the display of the minimum amount of free stack which each
                                                   >> 616           task has ever had available in the sysrq-T and sysrq-P debug output.
                                                   >> 617 
                                                   >> 618           This option will slow down process creation somewhat.
796                                                   619 
797 config DEBUG_VM                                   620 config DEBUG_VM
798         bool "Debug VM"                           621         bool "Debug VM"
799         depends on DEBUG_KERNEL                   622         depends on DEBUG_KERNEL
800         help                                      623         help
801           Enable this to turn on extended chec    624           Enable this to turn on extended checks in the virtual-memory system
802           that may impact performance.         !! 625           that may impact performance.
803                                                   626 
804           If unsure, say N.                       627           If unsure, say N.
805                                                   628 
806 config DEBUG_VM_SHOOT_LAZIES                   !! 629 config DEBUG_VM_VMACACHE
807         bool "Debug MMU_LAZY_TLB_SHOOTDOWN imp !! 630         bool "Debug VMA caching"
808         depends on DEBUG_VM                       631         depends on DEBUG_VM
809         depends on MMU_LAZY_TLB_SHOOTDOWN      << 
810         help                                      632         help
811           Enable additional IPIs that ensure l !! 633           Enable this to turn on VMA caching debug information. Doing so
812           before the mm is freed.              !! 634           can cause significant overhead, so only enable it in non-production
813                                                !! 635           environments.
814           If unsure, say N.                    << 
815                                                << 
816 config DEBUG_VM_MAPLE_TREE                     << 
817         bool "Debug VM maple trees"            << 
818         depends on DEBUG_VM                    << 
819         select DEBUG_MAPLE_TREE                << 
820         help                                   << 
821           Enable VM maple tree debugging infor << 
822                                                   636 
823           If unsure, say N.                       637           If unsure, say N.
824                                                   638 
825 config DEBUG_VM_RB                                639 config DEBUG_VM_RB
826         bool "Debug VM red-black trees"           640         bool "Debug VM red-black trees"
827         depends on DEBUG_VM                       641         depends on DEBUG_VM
828         help                                      642         help
829           Enable VM red-black tree debugging i    643           Enable VM red-black tree debugging information and extra validations.
830                                                   644 
831           If unsure, say N.                       645           If unsure, say N.
832                                                   646 
833 config DEBUG_VM_PGFLAGS                           647 config DEBUG_VM_PGFLAGS
834         bool "Debug page-flags operations"        648         bool "Debug page-flags operations"
835         depends on DEBUG_VM                       649         depends on DEBUG_VM
836         help                                      650         help
837           Enables extra validation on page fla    651           Enables extra validation on page flags operations.
838                                                   652 
839           If unsure, say N.                       653           If unsure, say N.
840                                                   654 
841 config DEBUG_VM_PGTABLE                        << 
842         bool "Debug arch page table for semant << 
843         depends on MMU                         << 
844         depends on ARCH_HAS_DEBUG_VM_PGTABLE   << 
845         default y if DEBUG_VM                  << 
846         help                                   << 
847           This option provides a debug method  << 
848           architecture page table helper funct << 
849           verifying if they comply with expect << 
850           will help architecture code in makin << 
851           new additions of these helpers still << 
852           semantics of the generic MM. Platfor << 
853           this through ARCH_HAS_DEBUG_VM_PGTAB << 
854                                                << 
855           If unsure, say N.                    << 
856                                                << 
857 config ARCH_HAS_DEBUG_VIRTUAL                     655 config ARCH_HAS_DEBUG_VIRTUAL
858         bool                                      656         bool
859                                                   657 
860 config DEBUG_VIRTUAL                              658 config DEBUG_VIRTUAL
861         bool "Debug VM translations"              659         bool "Debug VM translations"
862         depends on DEBUG_KERNEL && ARCH_HAS_DE    660         depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
863         help                                      661         help
864           Enable some costly sanity checks in     662           Enable some costly sanity checks in virtual to page code. This can
865           catch mistakes with virt_to_page() a    663           catch mistakes with virt_to_page() and friends.
866                                                   664 
867           If unsure, say N.                       665           If unsure, say N.
868                                                   666 
869 config DEBUG_NOMMU_REGIONS                        667 config DEBUG_NOMMU_REGIONS
870         bool "Debug the global anon/private NO    668         bool "Debug the global anon/private NOMMU mapping region tree"
871         depends on DEBUG_KERNEL && !MMU           669         depends on DEBUG_KERNEL && !MMU
872         help                                      670         help
873           This option causes the global tree o    671           This option causes the global tree of anonymous and private mapping
874           regions to be regularly checked for     672           regions to be regularly checked for invalid topology.
875                                                   673 
876 config DEBUG_MEMORY_INIT                          674 config DEBUG_MEMORY_INIT
877         bool "Debug memory initialisation" if     675         bool "Debug memory initialisation" if EXPERT
878         default !EXPERT                           676         default !EXPERT
879         help                                      677         help
880           Enable this for additional checks du    678           Enable this for additional checks during memory initialisation.
881           The sanity checks verify aspects of     679           The sanity checks verify aspects of the VM such as the memory model
882           and other information provided by th    680           and other information provided by the architecture. Verbose
883           information will be printed at KERN_    681           information will be printed at KERN_DEBUG loglevel depending
884           on the mminit_loglevel= command-line    682           on the mminit_loglevel= command-line option.
885                                                   683 
886           If unsure, say Y                        684           If unsure, say Y
887                                                   685 
888 config MEMORY_NOTIFIER_ERROR_INJECT               686 config MEMORY_NOTIFIER_ERROR_INJECT
889         tristate "Memory hotplug notifier erro    687         tristate "Memory hotplug notifier error injection module"
890         depends on MEMORY_HOTPLUG && NOTIFIER_ !! 688         depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
891         help                                      689         help
892           This option provides the ability to     690           This option provides the ability to inject artificial errors to
893           memory hotplug notifier chain callba    691           memory hotplug notifier chain callbacks.  It is controlled through
894           debugfs interface under /sys/kernel/    692           debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
895                                                   693 
896           If the notifier call chain should be    694           If the notifier call chain should be failed with some events
897           notified, write the error code to "a    695           notified, write the error code to "actions/<notifier event>/error".
898                                                   696 
899           Example: Inject memory hotplug offli    697           Example: Inject memory hotplug offline error (-12 == -ENOMEM)
900                                                   698 
901           # cd /sys/kernel/debug/notifier-erro    699           # cd /sys/kernel/debug/notifier-error-inject/memory
902           # echo -12 > actions/MEM_GOING_OFFLI    700           # echo -12 > actions/MEM_GOING_OFFLINE/error
903           # echo offline > /sys/devices/system    701           # echo offline > /sys/devices/system/memory/memoryXXX/state
904           bash: echo: write error: Cannot allo    702           bash: echo: write error: Cannot allocate memory
905                                                   703 
906           To compile this code as a module, ch    704           To compile this code as a module, choose M here: the module will
907           be called memory-notifier-error-inje    705           be called memory-notifier-error-inject.
908                                                   706 
909           If unsure, say N.                       707           If unsure, say N.
910                                                   708 
911 config DEBUG_PER_CPU_MAPS                         709 config DEBUG_PER_CPU_MAPS
912         bool "Debug access to per_cpu maps"       710         bool "Debug access to per_cpu maps"
913         depends on DEBUG_KERNEL                   711         depends on DEBUG_KERNEL
914         depends on SMP                            712         depends on SMP
915         help                                      713         help
916           Say Y to verify that the per_cpu map    714           Say Y to verify that the per_cpu map being accessed has
917           been set up. This adds a fair amount    715           been set up. This adds a fair amount of code to kernel memory
918           and decreases performance.              716           and decreases performance.
919                                                   717 
920           Say N if unsure.                        718           Say N if unsure.
921                                                   719 
922 config DEBUG_KMAP_LOCAL                        << 
923         bool "Debug kmap_local temporary mappi << 
924         depends on DEBUG_KERNEL && KMAP_LOCAL  << 
925         help                                   << 
926           This option enables additional error << 
927           infrastructure.  Disable for product << 
928                                                << 
929 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP      << 
930         bool                                   << 
931                                                << 
932 config DEBUG_KMAP_LOCAL_FORCE_MAP              << 
933         bool "Enforce kmap_local temporary map << 
934         depends on DEBUG_KERNEL && ARCH_SUPPOR << 
935         select KMAP_LOCAL                      << 
936         select DEBUG_KMAP_LOCAL                << 
937         help                                   << 
938           This option enforces temporary mappi << 
939           mechanism for non-highmem pages and  << 
940           Disable this for production systems! << 
941                                                << 
942 config DEBUG_HIGHMEM                              720 config DEBUG_HIGHMEM
943         bool "Highmem debugging"                  721         bool "Highmem debugging"
944         depends on DEBUG_KERNEL && HIGHMEM        722         depends on DEBUG_KERNEL && HIGHMEM
945         select DEBUG_KMAP_LOCAL_FORCE_MAP if A << 
946         select DEBUG_KMAP_LOCAL                << 
947         help                                      723         help
948           This option enables additional error    724           This option enables additional error checking for high memory
949           systems.  Disable for production sys    725           systems.  Disable for production systems.
950                                                   726 
951 config HAVE_DEBUG_STACKOVERFLOW                   727 config HAVE_DEBUG_STACKOVERFLOW
952         bool                                      728         bool
953                                                   729 
954 config DEBUG_STACKOVERFLOW                        730 config DEBUG_STACKOVERFLOW
955         bool "Check for stack overflows"          731         bool "Check for stack overflows"
956         depends on DEBUG_KERNEL && HAVE_DEBUG_    732         depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
957         help                                   !! 733         ---help---
958           Say Y here if you want to check for     734           Say Y here if you want to check for overflows of kernel, IRQ
959           and exception stacks (if your archit    735           and exception stacks (if your architecture uses them). This
960           option will show detailed messages i    736           option will show detailed messages if free stack space drops
961           below a certain limit.                  737           below a certain limit.
962                                                   738 
963           These kinds of bugs usually occur wh    739           These kinds of bugs usually occur when call-chains in the
964           kernel get too deep, especially when    740           kernel get too deep, especially when interrupts are
965           involved.                               741           involved.
966                                                   742 
967           Use this in cases where you see appa    743           Use this in cases where you see apparently random memory
968           corruption, especially if it appears    744           corruption, especially if it appears in 'struct thread_info'
969                                                   745 
970           If in doubt, say "N".                   746           If in doubt, say "N".
971                                                   747 
972 config CODE_TAGGING                            << 
973         bool                                   << 
974         select KALLSYMS                        << 
975                                                << 
976 config MEM_ALLOC_PROFILING                     << 
977         bool "Enable memory allocation profili << 
978         default n                              << 
979         depends on PROC_FS                     << 
980         depends on !DEBUG_FORCE_WEAK_PER_CPU   << 
981         select CODE_TAGGING                    << 
982         select PAGE_EXTENSION                  << 
983         select SLAB_OBJ_EXT                    << 
984         help                                   << 
985           Track allocation source code and rec << 
986           initiated at that code location. The << 
987           memory leaks with a low performance  << 
988                                                << 
989 config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT  << 
990         bool "Enable memory allocation profili << 
991         default y                              << 
992         depends on MEM_ALLOC_PROFILING         << 
993                                                << 
994 config MEM_ALLOC_PROFILING_DEBUG               << 
995         bool "Memory allocation profiler debug << 
996         default n                              << 
997         depends on MEM_ALLOC_PROFILING         << 
998         select MEM_ALLOC_PROFILING_ENABLED_BY_ << 
999         help                                   << 
1000           Adds warnings with helpful error me << 
1001           profiling.                          << 
1002                                               << 
1003 source "lib/Kconfig.kasan"                       748 source "lib/Kconfig.kasan"
1004 source "lib/Kconfig.kfence"                   << 
1005 source "lib/Kconfig.kmsan"                    << 
1006                                                  749 
1007 endmenu # "Memory Debugging"                     750 endmenu # "Memory Debugging"
1008                                                  751 
1009 config DEBUG_SHIRQ                            !! 752 config ARCH_HAS_KCOV
1010         bool "Debug shared IRQ handlers"      !! 753         bool
1011         depends on DEBUG_KERNEL               << 
1012         help                                     754         help
1013           Enable this to generate a spurious  !! 755           KCOV does not have any arch-specific code, but currently it is enabled
1014           interrupt handler is deregistered ( !! 756           only for x86_64. KCOV requires testing on other archs, and most likely
1015           is currently disabled). Drivers nee !! 757           disabling of instrumentation for some early boot code.
1016           don't and need to be caught.        << 
1017                                                  758 
1018 menu "Debug Oops, Lockups and Hangs"          !! 759 config CC_HAS_SANCOV_TRACE_PC
                                                   >> 760         def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1019                                                  761 
1020 config PANIC_ON_OOPS                          !! 762 config KCOV
1021         bool "Panic on Oops"                  !! 763         bool "Code coverage for fuzzing"
                                                   >> 764         depends on ARCH_HAS_KCOV
                                                   >> 765         depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
                                                   >> 766         select DEBUG_FS
                                                   >> 767         select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1022         help                                     768         help
1023           Say Y here to enable the kernel to  !! 769           KCOV exposes kernel code coverage information in a form suitable
1024           has the same effect as setting oops !! 770           for coverage-guided fuzzing (randomized testing).
1025           line.                               << 
1026                                                  771 
1027           This feature is useful to ensure th !! 772           If RANDOMIZE_BASE is enabled, PC values will not be stable across
1028           anything erroneous after an oops wh !! 773           different machines and across reboots. If you need stable PC values,
1029           corruption or other issues.         !! 774           disable RANDOMIZE_BASE.
1030                                                  775 
1031           Say N if unsure.                    !! 776           For more details, see Documentation/dev-tools/kcov.rst.
1032                                                  777 
1033 config PANIC_ON_OOPS_VALUE                    !! 778 config KCOV_ENABLE_COMPARISONS
1034         int                                   !! 779         bool "Enable comparison operands collection by KCOV"
1035         range 0 1                             !! 780         depends on KCOV
1036         default 0 if !PANIC_ON_OOPS           !! 781         depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1037         default 1 if PANIC_ON_OOPS            !! 782         help
                                                   >> 783           KCOV also exposes operands of every comparison in the instrumented
                                                   >> 784           code along with operand sizes and PCs of the comparison instructions.
                                                   >> 785           These operands can be used by fuzzing engines to improve the quality
                                                   >> 786           of fuzzing coverage.
1038                                                  787 
1039 config PANIC_TIMEOUT                          !! 788 config KCOV_INSTRUMENT_ALL
1040         int "panic timeout"                   !! 789         bool "Instrument all code by default"
1041         default 0                             !! 790         depends on KCOV
                                                   >> 791         default y
1042         help                                     792         help
1043           Set the timeout value (in seconds)  !! 793           If you are doing generic system call fuzzing (like e.g. syzkaller),
1044           the kernel panics. If n = 0, then w !! 794           then you will want to instrument the whole kernel and you should
1045           value n > 0 will wait n seconds bef !! 795           say y here. If you are doing more targeted fuzzing (like e.g.
1046           value n < 0 will reboot immediately !! 796           filesystem fuzzing with AFL) then you will want to enable coverage
1047           with the kernel command line option !! 797           for more specific subsets of files, and should say n here.
1048           /proc/sys/kernel/panic.             !! 798 
                                                   >> 799 config DEBUG_SHIRQ
                                                   >> 800         bool "Debug shared IRQ handlers"
                                                   >> 801         depends on DEBUG_KERNEL
                                                   >> 802         help
                                                   >> 803           Enable this to generate a spurious interrupt as soon as a shared
                                                   >> 804           interrupt handler is registered, and just before one is deregistered.
                                                   >> 805           Drivers ought to be able to handle interrupts coming in at those
                                                   >> 806           points; some don't and need to be caught.
                                                   >> 807 
                                                   >> 808 menu "Debug Lockups and Hangs"
1049                                                  809 
1050 config LOCKUP_DETECTOR                           810 config LOCKUP_DETECTOR
1051         bool                                     811         bool
1052                                                  812 
1053 config SOFTLOCKUP_DETECTOR                       813 config SOFTLOCKUP_DETECTOR
1054         bool "Detect Soft Lockups"               814         bool "Detect Soft Lockups"
1055         depends on DEBUG_KERNEL && !S390         815         depends on DEBUG_KERNEL && !S390
1056         select LOCKUP_DETECTOR                   816         select LOCKUP_DETECTOR
1057         help                                     817         help
1058           Say Y here to enable the kernel to     818           Say Y here to enable the kernel to act as a watchdog to detect
1059           soft lockups.                          819           soft lockups.
1060                                                  820 
1061           Softlockups are bugs that cause the    821           Softlockups are bugs that cause the kernel to loop in kernel
1062           mode for more than 20 seconds, with    822           mode for more than 20 seconds, without giving other tasks a
1063           chance to run.  The current stack t    823           chance to run.  The current stack trace is displayed upon
1064           detection and the system will stay     824           detection and the system will stay locked up.
1065                                                  825 
1066 config SOFTLOCKUP_DETECTOR_INTR_STORM         << 
1067         bool "Detect Interrupt Storm in Soft  << 
1068         depends on SOFTLOCKUP_DETECTOR && IRQ << 
1069         select GENERIC_IRQ_STAT_SNAPSHOT      << 
1070         default y if NR_CPUS <= 128           << 
1071         help                                  << 
1072           Say Y here to enable the kernel to  << 
1073           during "soft lockups".              << 
1074                                               << 
1075           "soft lockups" can be caused by a v << 
1076           caused by an interrupt storm, then  << 
1077           be on the callstack. To detect this << 
1078           the CPU stats and the interrupt cou << 
1079                                               << 
1080 config BOOTPARAM_SOFTLOCKUP_PANIC                826 config BOOTPARAM_SOFTLOCKUP_PANIC
1081         bool "Panic (Reboot) On Soft Lockups"    827         bool "Panic (Reboot) On Soft Lockups"
1082         depends on SOFTLOCKUP_DETECTOR           828         depends on SOFTLOCKUP_DETECTOR
1083         help                                     829         help
1084           Say Y here to enable the kernel to     830           Say Y here to enable the kernel to panic on "soft lockups",
1085           which are bugs that cause the kerne    831           which are bugs that cause the kernel to loop in kernel
1086           mode for more than 20 seconds (conf    832           mode for more than 20 seconds (configurable using the watchdog_thresh
1087           sysctl), without giving other tasks    833           sysctl), without giving other tasks a chance to run.
1088                                                  834 
1089           The panic can be used in combinatio    835           The panic can be used in combination with panic_timeout,
1090           to cause the system to reboot autom    836           to cause the system to reboot automatically after a
1091           lockup has been detected. This feat    837           lockup has been detected. This feature is useful for
1092           high-availability systems that have    838           high-availability systems that have uptime guarantees and
1093           where a lockup must be resolved ASA    839           where a lockup must be resolved ASAP.
1094                                                  840 
1095           Say N if unsure.                       841           Say N if unsure.
1096                                                  842 
1097 config HAVE_HARDLOCKUP_DETECTOR_BUDDY         !! 843 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
                                                   >> 844         int
                                                   >> 845         depends on SOFTLOCKUP_DETECTOR
                                                   >> 846         range 0 1
                                                   >> 847         default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
                                                   >> 848         default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
                                                   >> 849 
                                                   >> 850 config HARDLOCKUP_DETECTOR_PERF
1098         bool                                     851         bool
1099         depends on SMP                        !! 852         select SOFTLOCKUP_DETECTOR
1100         default y                             << 
1101                                                  853 
1102 #                                                854 #
1103 # Global switch whether to build a hardlockup !! 855 # Enables a timestamp based low pass filter to compensate for perf based
1104 # only when the architecture supports at leas !! 856 # hard lockup detection which runs too fast due to turbo modes.
1105 # two exceptions. The hardlockup detector is  << 
1106 #                                                857 #
1107 #       s390: it reported many false positive !! 858 config HARDLOCKUP_CHECK_TIMESTAMP
                                                   >> 859         bool
                                                   >> 860 
1108 #                                                861 #
1109 #       sparc64: has a custom implementation  !! 862 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1110 #               hardlockup command line optio !! 863 # lockup detector rather than the perf based detector.
1111 #                                                864 #
1112 config HARDLOCKUP_DETECTOR                       865 config HARDLOCKUP_DETECTOR
1113         bool "Detect Hard Lockups"               866         bool "Detect Hard Lockups"
1114         depends on DEBUG_KERNEL && !S390 && ! !! 867         depends on DEBUG_KERNEL && !S390
1115         depends on HAVE_HARDLOCKUP_DETECTOR_P !! 868         depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1116         imply HARDLOCKUP_DETECTOR_PERF        << 
1117         imply HARDLOCKUP_DETECTOR_BUDDY       << 
1118         imply HARDLOCKUP_DETECTOR_ARCH        << 
1119         select LOCKUP_DETECTOR                   869         select LOCKUP_DETECTOR
1120                                               !! 870         select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
                                                   >> 871         select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
1121         help                                     872         help
1122           Say Y here to enable the kernel to     873           Say Y here to enable the kernel to act as a watchdog to detect
1123           hard lockups.                          874           hard lockups.
1124                                                  875 
1125           Hardlockups are bugs that cause the    876           Hardlockups are bugs that cause the CPU to loop in kernel mode
1126           for more than 10 seconds, without l    877           for more than 10 seconds, without letting other interrupts have a
1127           chance to run.  The current stack t    878           chance to run.  The current stack trace is displayed upon detection
1128           and the system will stay locked up.    879           and the system will stay locked up.
1129                                                  880 
1130 #                                             << 
1131 # Note that arch-specific variants are always << 
1132 #                                             << 
1133 config HARDLOCKUP_DETECTOR_PREFER_BUDDY       << 
1134         bool "Prefer the buddy CPU hardlockup << 
1135         depends on HARDLOCKUP_DETECTOR        << 
1136         depends on HAVE_HARDLOCKUP_DETECTOR_P << 
1137         depends on !HAVE_HARDLOCKUP_DETECTOR_ << 
1138         help                                  << 
1139           Say Y here to prefer the buddy hard << 
1140                                               << 
1141           With the buddy detector, each CPU u << 
1142           to check that the next CPU is proce << 
1143           verifying that a counter is increas << 
1144                                               << 
1145           This hardlockup detector is useful  << 
1146           an arch-specific hardlockup detecto << 
1147           for the hardlockup detector are bet << 
1148                                               << 
1149 config HARDLOCKUP_DETECTOR_PERF               << 
1150         bool                                  << 
1151         depends on HARDLOCKUP_DETECTOR        << 
1152         depends on HAVE_HARDLOCKUP_DETECTOR_P << 
1153         depends on !HAVE_HARDLOCKUP_DETECTOR_ << 
1154         select HARDLOCKUP_DETECTOR_COUNTS_HRT << 
1155                                               << 
1156 config HARDLOCKUP_DETECTOR_BUDDY              << 
1157         bool                                  << 
1158         depends on HARDLOCKUP_DETECTOR        << 
1159         depends on HAVE_HARDLOCKUP_DETECTOR_B << 
1160         depends on !HAVE_HARDLOCKUP_DETECTOR_ << 
1161         depends on !HAVE_HARDLOCKUP_DETECTOR_ << 
1162         select HARDLOCKUP_DETECTOR_COUNTS_HRT << 
1163                                               << 
1164 config HARDLOCKUP_DETECTOR_ARCH               << 
1165         bool                                  << 
1166         depends on HARDLOCKUP_DETECTOR        << 
1167         depends on HAVE_HARDLOCKUP_DETECTOR_A << 
1168         help                                  << 
1169           The arch-specific implementation of << 
1170           be used.                            << 
1171                                               << 
1172 #                                             << 
1173 # Both the "perf" and "buddy" hardlockup dete << 
1174 # interrupts. This config enables functions m << 
1175 #                                             << 
1176 config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER     << 
1177         bool                                  << 
1178         select SOFTLOCKUP_DETECTOR            << 
1179                                               << 
1180 #                                             << 
1181 # Enables a timestamp based low pass filter t << 
1182 # hard lockup detection which runs too fast d << 
1183 #                                             << 
1184 config HARDLOCKUP_CHECK_TIMESTAMP             << 
1185         bool                                  << 
1186                                               << 
1187 config BOOTPARAM_HARDLOCKUP_PANIC                881 config BOOTPARAM_HARDLOCKUP_PANIC
1188         bool "Panic (Reboot) On Hard Lockups"    882         bool "Panic (Reboot) On Hard Lockups"
1189         depends on HARDLOCKUP_DETECTOR           883         depends on HARDLOCKUP_DETECTOR
1190         help                                     884         help
1191           Say Y here to enable the kernel to     885           Say Y here to enable the kernel to panic on "hard lockups",
1192           which are bugs that cause the kerne    886           which are bugs that cause the kernel to loop in kernel
1193           mode with interrupts disabled for m    887           mode with interrupts disabled for more than 10 seconds (configurable
1194           using the watchdog_thresh sysctl).     888           using the watchdog_thresh sysctl).
1195                                                  889 
1196           Say N if unsure.                       890           Say N if unsure.
1197                                                  891 
                                                   >> 892 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
                                                   >> 893         int
                                                   >> 894         depends on HARDLOCKUP_DETECTOR
                                                   >> 895         range 0 1
                                                   >> 896         default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
                                                   >> 897         default 1 if BOOTPARAM_HARDLOCKUP_PANIC
                                                   >> 898 
1198 config DETECT_HUNG_TASK                          899 config DETECT_HUNG_TASK
1199         bool "Detect Hung Tasks"                 900         bool "Detect Hung Tasks"
1200         depends on DEBUG_KERNEL                  901         depends on DEBUG_KERNEL
1201         default SOFTLOCKUP_DETECTOR              902         default SOFTLOCKUP_DETECTOR
1202         help                                     903         help
1203           Say Y here to enable the kernel to     904           Say Y here to enable the kernel to detect "hung tasks",
1204           which are bugs that cause the task     905           which are bugs that cause the task to be stuck in
1205           uninterruptible "D" state indefinit    906           uninterruptible "D" state indefinitely.
1206                                                  907 
1207           When a hung task is detected, the k    908           When a hung task is detected, the kernel will print the
1208           current stack trace (which you shou    909           current stack trace (which you should report), but the
1209           task will stay in uninterruptible s    910           task will stay in uninterruptible state. If lockdep is
1210           enabled then all held locks will al    911           enabled then all held locks will also be reported. This
1211           feature has negligible overhead.       912           feature has negligible overhead.
1212                                                  913 
1213 config DEFAULT_HUNG_TASK_TIMEOUT                 914 config DEFAULT_HUNG_TASK_TIMEOUT
1214         int "Default timeout for hung task de    915         int "Default timeout for hung task detection (in seconds)"
1215         depends on DETECT_HUNG_TASK              916         depends on DETECT_HUNG_TASK
1216         default 120                              917         default 120
1217         help                                     918         help
1218           This option controls the default ti    919           This option controls the default timeout (in seconds) used
1219           to determine when a task has become    920           to determine when a task has become non-responsive and should
1220           be considered hung.                    921           be considered hung.
1221                                                  922 
1222           It can be adjusted at runtime via t    923           It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1223           sysctl or by writing a value to        924           sysctl or by writing a value to
1224           /proc/sys/kernel/hung_task_timeout_    925           /proc/sys/kernel/hung_task_timeout_secs.
1225                                                  926 
1226           A timeout of 0 disables the check.     927           A timeout of 0 disables the check.  The default is two minutes.
1227           Keeping the default should be fine     928           Keeping the default should be fine in most cases.
1228                                                  929 
1229 config BOOTPARAM_HUNG_TASK_PANIC                 930 config BOOTPARAM_HUNG_TASK_PANIC
1230         bool "Panic (Reboot) On Hung Tasks"      931         bool "Panic (Reboot) On Hung Tasks"
1231         depends on DETECT_HUNG_TASK              932         depends on DETECT_HUNG_TASK
1232         help                                     933         help
1233           Say Y here to enable the kernel to     934           Say Y here to enable the kernel to panic on "hung tasks",
1234           which are bugs that cause the kerne    935           which are bugs that cause the kernel to leave a task stuck
1235           in uninterruptible "D" state.          936           in uninterruptible "D" state.
1236                                                  937 
1237           The panic can be used in combinatio    938           The panic can be used in combination with panic_timeout,
1238           to cause the system to reboot autom    939           to cause the system to reboot automatically after a
1239           hung task has been detected. This f    940           hung task has been detected. This feature is useful for
1240           high-availability systems that have    941           high-availability systems that have uptime guarantees and
1241           where a hung tasks must be resolved    942           where a hung tasks must be resolved ASAP.
1242                                                  943 
1243           Say N if unsure.                       944           Say N if unsure.
1244                                                  945 
                                                   >> 946 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
                                                   >> 947         int
                                                   >> 948         depends on DETECT_HUNG_TASK
                                                   >> 949         range 0 1
                                                   >> 950         default 0 if !BOOTPARAM_HUNG_TASK_PANIC
                                                   >> 951         default 1 if BOOTPARAM_HUNG_TASK_PANIC
                                                   >> 952 
1245 config WQ_WATCHDOG                               953 config WQ_WATCHDOG
1246         bool "Detect Workqueue Stalls"           954         bool "Detect Workqueue Stalls"
1247         depends on DEBUG_KERNEL                  955         depends on DEBUG_KERNEL
1248         help                                     956         help
1249           Say Y here to enable stall detectio    957           Say Y here to enable stall detection on workqueues.  If a
1250           worker pool doesn't make forward pr    958           worker pool doesn't make forward progress on a pending work
1251           item for over a given amount of tim    959           item for over a given amount of time, 30s by default, a
1252           warning message is printed along wi    960           warning message is printed along with dump of workqueue
1253           state.  This can be configured thro    961           state.  This can be configured through kernel parameter
1254           "workqueue.watchdog_thresh" and its    962           "workqueue.watchdog_thresh" and its sysfs counterpart.
1255                                                  963 
1256 config WQ_CPU_INTENSIVE_REPORT                !! 964 endmenu # "Debug lockups and hangs"
1257         bool "Report per-cpu work items which << 
1258         depends on DEBUG_KERNEL               << 
1259         help                                  << 
1260           Say Y here to enable reporting of c << 
1261           items that hog CPUs for longer than << 
1262           workqueue.cpu_intensive_thresh_us.  << 
1263           detects and excludes them from conc << 
1264           them from stalling other per-cpu wo << 
1265           triggering may not necessarily indi << 
1266           triggering likely indicates that th << 
1267           to use an unbound workqueue.        << 
1268                                                  965 
1269 config TEST_LOCKUP                            !! 966 config PANIC_ON_OOPS
1270         tristate "Test module to generate loc !! 967         bool "Panic on Oops"
1271         depends on m                          << 
1272         help                                     968         help
1273           This builds the "test_lockup" modul !! 969           Say Y here to enable the kernel to panic when it oopses. This
1274           that watchdogs and lockup detectors !! 970           has the same effect as setting oops=panic on the kernel command
                                                   >> 971           line.
1275                                                  972 
1276           Depending on module parameters it c !! 973           This feature is useful to ensure that the kernel does not do
1277           lockup, "hung task", or locking arb !! 974           anything erroneous after an oops which could result in data
1278           Also it could generate series of lo !! 975           corruption or other issues.
1279                                                  976 
1280           If unsure, say N.                   !! 977           Say N if unsure.
1281                                                  978 
1282 endmenu # "Debug lockups and hangs"           !! 979 config PANIC_ON_OOPS_VALUE
                                                   >> 980         int
                                                   >> 981         range 0 1
                                                   >> 982         default 0 if !PANIC_ON_OOPS
                                                   >> 983         default 1 if PANIC_ON_OOPS
1283                                                  984 
1284 menu "Scheduler Debugging"                    !! 985 config PANIC_TIMEOUT
                                                   >> 986         int "panic timeout"
                                                   >> 987         default 0
                                                   >> 988         help
                                                   >> 989           Set the timeout value (in seconds) until a reboot occurs when the
                                                   >> 990           the kernel panics. If n = 0, then we wait forever. A timeout
                                                   >> 991           value n > 0 will wait n seconds before rebooting, while a timeout
                                                   >> 992           value n < 0 will reboot immediately.
1285                                                  993 
1286 config SCHED_DEBUG                               994 config SCHED_DEBUG
1287         bool "Collect scheduler debugging inf    995         bool "Collect scheduler debugging info"
1288         depends on DEBUG_KERNEL && DEBUG_FS   !! 996         depends on DEBUG_KERNEL && PROC_FS
1289         default y                                997         default y
1290         help                                     998         help
1291           If you say Y here, the /sys/kernel/ !! 999           If you say Y here, the /proc/sched_debug file will be provided
1292           that can help debug the scheduler.     1000           that can help debug the scheduler. The runtime overhead of this
1293           option is minimal.                     1001           option is minimal.
1294                                                  1002 
1295 config SCHED_INFO                                1003 config SCHED_INFO
1296         bool                                     1004         bool
1297         default n                                1005         default n
1298                                                  1006 
1299 config SCHEDSTATS                                1007 config SCHEDSTATS
1300         bool "Collect scheduler statistics"      1008         bool "Collect scheduler statistics"
1301         depends on PROC_FS                    !! 1009         depends on DEBUG_KERNEL && PROC_FS
1302         select SCHED_INFO                        1010         select SCHED_INFO
1303         help                                     1011         help
1304           If you say Y here, additional code     1012           If you say Y here, additional code will be inserted into the
1305           scheduler and related routines to c    1013           scheduler and related routines to collect statistics about
1306           scheduler behavior and provide them    1014           scheduler behavior and provide them in /proc/schedstat.  These
1307           stats may be useful for both tuning    1015           stats may be useful for both tuning and debugging the scheduler
1308           If you aren't debugging the schedul    1016           If you aren't debugging the scheduler or trying to tune a specific
1309           application, you can say N to avoid    1017           application, you can say N to avoid the very slight overhead
1310           this adds.                             1018           this adds.
1311                                                  1019 
1312 endmenu                                       !! 1020 config SCHED_STACK_END_CHECK
                                                   >> 1021         bool "Detect stack corruption on calls to schedule()"
                                                   >> 1022         depends on DEBUG_KERNEL
                                                   >> 1023         default n
                                                   >> 1024         help
                                                   >> 1025           This option checks for a stack overrun on calls to schedule().
                                                   >> 1026           If the stack end location is found to be over written always panic as
                                                   >> 1027           the content of the corrupted region can no longer be trusted.
                                                   >> 1028           This is to ensure no erroneous behaviour occurs which could result in
                                                   >> 1029           data corruption or a sporadic crash at a later stage once the region
                                                   >> 1030           is examined. The runtime overhead introduced is minimal.
1313                                                  1031 
1314 config DEBUG_TIMEKEEPING                         1032 config DEBUG_TIMEKEEPING
1315         bool "Enable extra timekeeping sanity    1033         bool "Enable extra timekeeping sanity checking"
1316         help                                     1034         help
1317           This option will enable additional     1035           This option will enable additional timekeeping sanity checks
1318           which may be helpful when diagnosin    1036           which may be helpful when diagnosing issues where timekeeping
1319           problems are suspected.                1037           problems are suspected.
1320                                                  1038 
1321           This may include checks in the time    1039           This may include checks in the timekeeping hotpaths, so this
1322           option may have a (very small) perf    1040           option may have a (very small) performance impact to some
1323           workloads.                             1041           workloads.
1324                                                  1042 
1325           If unsure, say N.                      1043           If unsure, say N.
1326                                                  1044 
1327 config DEBUG_PREEMPT                             1045 config DEBUG_PREEMPT
1328         bool "Debug preemptible kernel"          1046         bool "Debug preemptible kernel"
1329         depends on DEBUG_KERNEL && PREEMPTION !! 1047         depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
                                                   >> 1048         default y
1330         help                                     1049         help
1331           If you say Y here then the kernel w    1050           If you say Y here then the kernel will use a debug variant of the
1332           commonly used smp_processor_id() fu    1051           commonly used smp_processor_id() function and will print warnings
1333           if kernel code uses it in a preempt    1052           if kernel code uses it in a preemption-unsafe way. Also, the kernel
1334           will detect preemption count underf    1053           will detect preemption count underflows.
1335                                                  1054 
1336           This option has potential to introd << 
1337           depending on workload as it trigger << 
1338           this_cpu operation. It should only  << 
1339                                               << 
1340 menu "Lock Debugging (spinlocks, mutexes, etc    1055 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1341                                                  1056 
1342 config LOCK_DEBUGGING_SUPPORT                    1057 config LOCK_DEBUGGING_SUPPORT
1343         bool                                     1058         bool
1344         depends on TRACE_IRQFLAGS_SUPPORT &&     1059         depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1345         default y                                1060         default y
1346                                                  1061 
1347 config PROVE_LOCKING                             1062 config PROVE_LOCKING
1348         bool "Lock debugging: prove locking c    1063         bool "Lock debugging: prove locking correctness"
1349         depends on DEBUG_KERNEL && LOCK_DEBUG    1064         depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1350         select LOCKDEP                           1065         select LOCKDEP
1351         select DEBUG_SPINLOCK                    1066         select DEBUG_SPINLOCK
1352         select DEBUG_MUTEXES if !PREEMPT_RT   !! 1067         select DEBUG_MUTEXES
1353         select DEBUG_RT_MUTEXES if RT_MUTEXES    1068         select DEBUG_RT_MUTEXES if RT_MUTEXES
1354         select DEBUG_RWSEMS if !PREEMPT_RT    !! 1069         select DEBUG_RWSEMS if RWSEM_SPIN_ON_OWNER
1355         select DEBUG_WW_MUTEX_SLOWPATH           1070         select DEBUG_WW_MUTEX_SLOWPATH
1356         select DEBUG_LOCK_ALLOC                  1071         select DEBUG_LOCK_ALLOC
1357         select PREEMPT_COUNT if !ARCH_NO_PREE << 
1358         select TRACE_IRQFLAGS                    1072         select TRACE_IRQFLAGS
1359         default n                                1073         default n
1360         help                                     1074         help
1361          This feature enables the kernel to p    1075          This feature enables the kernel to prove that all locking
1362          that occurs in the kernel runtime is    1076          that occurs in the kernel runtime is mathematically
1363          correct: that under no circumstance     1077          correct: that under no circumstance could an arbitrary (and
1364          not yet triggered) combination of ob    1078          not yet triggered) combination of observed locking
1365          sequences (on an arbitrary number of    1079          sequences (on an arbitrary number of CPUs, running an
1366          arbitrary number of tasks and interr    1080          arbitrary number of tasks and interrupt contexts) cause a
1367          deadlock.                               1081          deadlock.
1368                                                  1082 
1369          In short, this feature enables the k    1083          In short, this feature enables the kernel to report locking
1370          related deadlocks before they actual    1084          related deadlocks before they actually occur.
1371                                                  1085 
1372          The proof does not depend on how har    1086          The proof does not depend on how hard and complex a
1373          deadlock scenario would be to trigge    1087          deadlock scenario would be to trigger: how many
1374          participant CPUs, tasks and irq-cont    1088          participant CPUs, tasks and irq-contexts would be needed
1375          for it to trigger. The proof also do    1089          for it to trigger. The proof also does not depend on
1376          timing: if a race and a resulting de    1090          timing: if a race and a resulting deadlock is possible
1377          theoretically (no matter how unlikel    1091          theoretically (no matter how unlikely the race scenario
1378          is), it will be proven so and will i    1092          is), it will be proven so and will immediately be
1379          reported by the kernel (once the eve    1093          reported by the kernel (once the event is observed that
1380          makes the deadlock theoretically pos    1094          makes the deadlock theoretically possible).
1381                                                  1095 
1382          If a deadlock is impossible (i.e. th    1096          If a deadlock is impossible (i.e. the locking rules, as
1383          observed by the kernel, are mathemat    1097          observed by the kernel, are mathematically correct), the
1384          kernel reports nothing.                 1098          kernel reports nothing.
1385                                                  1099 
1386          NOTE: this feature can also be enabl    1100          NOTE: this feature can also be enabled for rwlocks, mutexes
1387          and rwsems - in which case all depen    1101          and rwsems - in which case all dependencies between these
1388          different locking variants are obser    1102          different locking variants are observed and mapped too, and
1389          the proof of observed correctness is    1103          the proof of observed correctness is also maintained for an
1390          arbitrary combination of these separ    1104          arbitrary combination of these separate locking variants.
1391                                                  1105 
1392          For more details, see Documentation/ !! 1106          For more details, see Documentation/locking/lockdep-design.txt.
1393                                               << 
1394 config PROVE_RAW_LOCK_NESTING                 << 
1395         bool "Enable raw_spinlock - spinlock  << 
1396         depends on PROVE_LOCKING              << 
1397         default n                             << 
1398         help                                  << 
1399          Enable the raw_spinlock vs. spinlock << 
1400          that the lock nesting rules for PREE << 
1401          not violated.                        << 
1402                                               << 
1403          NOTE: There are known nesting proble << 
1404          option expect lockdep splats until t << 
1405          addressed which is work in progress. << 
1406          identify and analyze these problems. << 
1407          check permanently enabled once the m << 
1408                                               << 
1409          If unsure, select N.                 << 
1410                                                  1107 
1411 config LOCK_STAT                                 1108 config LOCK_STAT
1412         bool "Lock usage statistics"             1109         bool "Lock usage statistics"
1413         depends on DEBUG_KERNEL && LOCK_DEBUG    1110         depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1414         select LOCKDEP                           1111         select LOCKDEP
1415         select DEBUG_SPINLOCK                    1112         select DEBUG_SPINLOCK
1416         select DEBUG_MUTEXES if !PREEMPT_RT   !! 1113         select DEBUG_MUTEXES
1417         select DEBUG_RT_MUTEXES if RT_MUTEXES    1114         select DEBUG_RT_MUTEXES if RT_MUTEXES
1418         select DEBUG_LOCK_ALLOC                  1115         select DEBUG_LOCK_ALLOC
1419         default n                                1116         default n
1420         help                                     1117         help
1421          This feature enables tracking lock c    1118          This feature enables tracking lock contention points
1422                                                  1119 
1423          For more details, see Documentation/ !! 1120          For more details, see Documentation/locking/lockstat.txt
1424                                                  1121 
1425          This also enables lock events requir    1122          This also enables lock events required by "perf lock",
1426          subcommand of perf.                     1123          subcommand of perf.
1427          If you want to use "perf lock", you     1124          If you want to use "perf lock", you also need to turn on
1428          CONFIG_EVENT_TRACING.                   1125          CONFIG_EVENT_TRACING.
1429                                                  1126 
1430          CONFIG_LOCK_STAT defines "contended"    1127          CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1431          (CONFIG_LOCKDEP defines "acquire" an    1128          (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1432                                                  1129 
1433 config DEBUG_RT_MUTEXES                          1130 config DEBUG_RT_MUTEXES
1434         bool "RT Mutex debugging, deadlock de    1131         bool "RT Mutex debugging, deadlock detection"
1435         depends on DEBUG_KERNEL && RT_MUTEXES    1132         depends on DEBUG_KERNEL && RT_MUTEXES
1436         help                                     1133         help
1437          This allows rt mutex semantics viola    1134          This allows rt mutex semantics violations and rt mutex related
1438          deadlocks (lockups) to be detected a    1135          deadlocks (lockups) to be detected and reported automatically.
1439                                                  1136 
1440 config DEBUG_SPINLOCK                            1137 config DEBUG_SPINLOCK
1441         bool "Spinlock and rw-lock debugging:    1138         bool "Spinlock and rw-lock debugging: basic checks"
1442         depends on DEBUG_KERNEL                  1139         depends on DEBUG_KERNEL
1443         select UNINLINE_SPIN_UNLOCK              1140         select UNINLINE_SPIN_UNLOCK
1444         help                                     1141         help
1445           Say Y here and build SMP to catch m    1142           Say Y here and build SMP to catch missing spinlock initialization
1446           and certain other kinds of spinlock    1143           and certain other kinds of spinlock errors commonly made.  This is
1447           best used in conjunction with the N    1144           best used in conjunction with the NMI watchdog so that spinlock
1448           deadlocks are also debuggable.         1145           deadlocks are also debuggable.
1449                                                  1146 
1450 config DEBUG_MUTEXES                             1147 config DEBUG_MUTEXES
1451         bool "Mutex debugging: basic checks"     1148         bool "Mutex debugging: basic checks"
1452         depends on DEBUG_KERNEL && !PREEMPT_R !! 1149         depends on DEBUG_KERNEL
1453         help                                     1150         help
1454          This feature allows mutex semantics     1151          This feature allows mutex semantics violations to be detected and
1455          reported.                               1152          reported.
1456                                                  1153 
1457 config DEBUG_WW_MUTEX_SLOWPATH                   1154 config DEBUG_WW_MUTEX_SLOWPATH
1458         bool "Wait/wound mutex debugging: Slo    1155         bool "Wait/wound mutex debugging: Slowpath testing"
1459         depends on DEBUG_KERNEL && LOCK_DEBUG    1156         depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1460         select DEBUG_LOCK_ALLOC                  1157         select DEBUG_LOCK_ALLOC
1461         select DEBUG_SPINLOCK                    1158         select DEBUG_SPINLOCK
1462         select DEBUG_MUTEXES if !PREEMPT_RT   !! 1159         select DEBUG_MUTEXES
1463         select DEBUG_RT_MUTEXES if PREEMPT_RT << 
1464         help                                     1160         help
1465          This feature enables slowpath testin    1161          This feature enables slowpath testing for w/w mutex users by
1466          injecting additional -EDEADLK wound/    1162          injecting additional -EDEADLK wound/backoff cases. Together with
1467          the full mutex checks enabled with (    1163          the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1468          will test all possible w/w mutex int    1164          will test all possible w/w mutex interface abuse with the
1469          exception of simply not acquiring al    1165          exception of simply not acquiring all the required locks.
1470          Note that this feature can introduce    1166          Note that this feature can introduce significant overhead, so
1471          it really should not be enabled in a    1167          it really should not be enabled in a production or distro kernel,
1472          even a debug kernel.  If you are a d    1168          even a debug kernel.  If you are a driver writer, enable it.  If
1473          you are a distro, do not.               1169          you are a distro, do not.
1474                                                  1170 
1475 config DEBUG_RWSEMS                              1171 config DEBUG_RWSEMS
1476         bool "RW Semaphore debugging: basic c    1172         bool "RW Semaphore debugging: basic checks"
1477         depends on DEBUG_KERNEL && !PREEMPT_R !! 1173         depends on DEBUG_KERNEL && RWSEM_SPIN_ON_OWNER
1478         help                                     1174         help
1479           This debugging feature allows misma !! 1175           This debugging feature allows mismatched rw semaphore locks and unlocks
1480           and unlocks to be detected and repo !! 1176           to be detected and reported.
1481                                                  1177 
1482 config DEBUG_LOCK_ALLOC                          1178 config DEBUG_LOCK_ALLOC
1483         bool "Lock debugging: detect incorrec    1179         bool "Lock debugging: detect incorrect freeing of live locks"
1484         depends on DEBUG_KERNEL && LOCK_DEBUG    1180         depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1485         select DEBUG_SPINLOCK                    1181         select DEBUG_SPINLOCK
1486         select DEBUG_MUTEXES if !PREEMPT_RT   !! 1182         select DEBUG_MUTEXES
1487         select DEBUG_RT_MUTEXES if RT_MUTEXES    1183         select DEBUG_RT_MUTEXES if RT_MUTEXES
1488         select LOCKDEP                           1184         select LOCKDEP
1489         help                                     1185         help
1490          This feature will check whether any     1186          This feature will check whether any held lock (spinlock, rwlock,
1491          mutex or rwsem) is incorrectly freed    1187          mutex or rwsem) is incorrectly freed by the kernel, via any of the
1492          memory-freeing routines (kfree(), km    1188          memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1493          vfree(), etc.), whether a live lock     1189          vfree(), etc.), whether a live lock is incorrectly reinitialized via
1494          spin_lock_init()/mutex_init()/etc.,     1190          spin_lock_init()/mutex_init()/etc., or whether there is any lock
1495          held during task exit.                  1191          held during task exit.
1496                                                  1192 
1497 config LOCKDEP                                   1193 config LOCKDEP
1498         bool                                     1194         bool
1499         depends on DEBUG_KERNEL && LOCK_DEBUG    1195         depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1500         select STACKTRACE                        1196         select STACKTRACE
                                                   >> 1197         select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
1501         select KALLSYMS                          1198         select KALLSYMS
1502         select KALLSYMS_ALL                      1199         select KALLSYMS_ALL
1503                                                  1200 
1504 config LOCKDEP_SMALL                             1201 config LOCKDEP_SMALL
1505         bool                                     1202         bool
1506                                                  1203 
1507 config LOCKDEP_BITS                           << 
1508         int "Bitsize for MAX_LOCKDEP_ENTRIES" << 
1509         depends on LOCKDEP && !LOCKDEP_SMALL  << 
1510         range 10 30                           << 
1511         default 15                            << 
1512         help                                  << 
1513           Try increasing this value if you hi << 
1514                                               << 
1515 config LOCKDEP_CHAINS_BITS                    << 
1516         int "Bitsize for MAX_LOCKDEP_CHAINS"  << 
1517         depends on LOCKDEP && !LOCKDEP_SMALL  << 
1518         range 10 30                           << 
1519         default 16                            << 
1520         help                                  << 
1521           Try increasing this value if you hi << 
1522                                               << 
1523 config LOCKDEP_STACK_TRACE_BITS               << 
1524         int "Bitsize for MAX_STACK_TRACE_ENTR << 
1525         depends on LOCKDEP && !LOCKDEP_SMALL  << 
1526         range 10 30                           << 
1527         default 19                            << 
1528         help                                  << 
1529           Try increasing this value if you hi << 
1530                                               << 
1531 config LOCKDEP_STACK_TRACE_HASH_BITS          << 
1532         int "Bitsize for STACK_TRACE_HASH_SIZ << 
1533         depends on LOCKDEP && !LOCKDEP_SMALL  << 
1534         range 10 30                           << 
1535         default 14                            << 
1536         help                                  << 
1537           Try increasing this value if you ne << 
1538                                               << 
1539 config LOCKDEP_CIRCULAR_QUEUE_BITS            << 
1540         int "Bitsize for elements in circular << 
1541         depends on LOCKDEP                    << 
1542         range 10 30                           << 
1543         default 12                            << 
1544         help                                  << 
1545           Try increasing this value if you hi << 
1546                                               << 
1547 config DEBUG_LOCKDEP                             1204 config DEBUG_LOCKDEP
1548         bool "Lock dependency engine debuggin    1205         bool "Lock dependency engine debugging"
1549         depends on DEBUG_KERNEL && LOCKDEP       1206         depends on DEBUG_KERNEL && LOCKDEP
1550         select DEBUG_IRQFLAGS                 << 
1551         help                                     1207         help
1552           If you say Y here, the lock depende    1208           If you say Y here, the lock dependency engine will do
1553           additional runtime checks to debug     1209           additional runtime checks to debug itself, at the price
1554           of more runtime overhead.              1210           of more runtime overhead.
1555                                                  1211 
1556 config DEBUG_ATOMIC_SLEEP                        1212 config DEBUG_ATOMIC_SLEEP
1557         bool "Sleep inside atomic section che    1213         bool "Sleep inside atomic section checking"
1558         select PREEMPT_COUNT                     1214         select PREEMPT_COUNT
1559         depends on DEBUG_KERNEL                  1215         depends on DEBUG_KERNEL
1560         depends on !ARCH_NO_PREEMPT              1216         depends on !ARCH_NO_PREEMPT
1561         help                                     1217         help
1562           If you say Y here, various routines    1218           If you say Y here, various routines which may sleep will become very
1563           noisy if they are called inside ato    1219           noisy if they are called inside atomic sections: when a spinlock is
1564           held, inside an rcu read side criti    1220           held, inside an rcu read side critical section, inside preempt disabled
1565           sections, inside an interrupt, etc.    1221           sections, inside an interrupt, etc...
1566                                                  1222 
1567 config DEBUG_LOCKING_API_SELFTESTS               1223 config DEBUG_LOCKING_API_SELFTESTS
1568         bool "Locking API boot-time self-test    1224         bool "Locking API boot-time self-tests"
1569         depends on DEBUG_KERNEL                  1225         depends on DEBUG_KERNEL
1570         help                                     1226         help
1571           Say Y here if you want the kernel t    1227           Say Y here if you want the kernel to run a short self-test during
1572           bootup. The self-test checks whethe    1228           bootup. The self-test checks whether common types of locking bugs
1573           are detected by debugging mechanism    1229           are detected by debugging mechanisms or not. (if you disable
1574           lock debugging then those bugs won' !! 1230           lock debugging then those bugs wont be detected of course.)
1575           The following locking APIs are cove    1231           The following locking APIs are covered: spinlocks, rwlocks,
1576           mutexes and rwsems.                    1232           mutexes and rwsems.
1577                                                  1233 
1578 config LOCK_TORTURE_TEST                         1234 config LOCK_TORTURE_TEST
1579         tristate "torture tests for locking"     1235         tristate "torture tests for locking"
1580         depends on DEBUG_KERNEL                  1236         depends on DEBUG_KERNEL
1581         select TORTURE_TEST                      1237         select TORTURE_TEST
1582         help                                     1238         help
1583           This option provides a kernel modul    1239           This option provides a kernel module that runs torture tests
1584           on kernel locking primitives.  The     1240           on kernel locking primitives.  The kernel module may be built
1585           after the fact on the running kerne    1241           after the fact on the running kernel to be tested, if desired.
1586                                                  1242 
1587           Say Y here if you want kernel locki    1243           Say Y here if you want kernel locking-primitive torture tests
1588           to be built into the kernel.           1244           to be built into the kernel.
1589           Say M if you want these torture tes    1245           Say M if you want these torture tests to build as a module.
1590           Say N if you are unsure.               1246           Say N if you are unsure.
1591                                                  1247 
1592 config WW_MUTEX_SELFTEST                         1248 config WW_MUTEX_SELFTEST
1593         tristate "Wait/wound mutex selftests"    1249         tristate "Wait/wound mutex selftests"
1594         help                                     1250         help
1595           This option provides a kernel modul    1251           This option provides a kernel module that runs tests on the
1596           on the struct ww_mutex locking API.    1252           on the struct ww_mutex locking API.
1597                                                  1253 
1598           It is recommended to enable DEBUG_W    1254           It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1599           with this test harness.                1255           with this test harness.
1600                                                  1256 
1601           Say M if you want these self tests     1257           Say M if you want these self tests to build as a module.
1602           Say N if you are unsure.               1258           Say N if you are unsure.
1603                                                  1259 
1604 config SCF_TORTURE_TEST                       << 
1605         tristate "torture tests for smp_call_ << 
1606         depends on DEBUG_KERNEL               << 
1607         select TORTURE_TEST                   << 
1608         help                                  << 
1609           This option provides a kernel modul << 
1610           on the smp_call_function() family o << 
1611           module may be built after the fact  << 
1612           be tested, if desired.              << 
1613                                               << 
1614 config CSD_LOCK_WAIT_DEBUG                    << 
1615         bool "Debugging for csd_lock_wait(),  << 
1616         depends on DEBUG_KERNEL               << 
1617         depends on 64BIT                      << 
1618         default n                             << 
1619         help                                  << 
1620           This option enables debug prints wh << 
1621           to the smp_call_function*() IPI wra << 
1622           include the IPI handler function cu << 
1623           and relevant stack traces.          << 
1624                                               << 
1625 config CSD_LOCK_WAIT_DEBUG_DEFAULT            << 
1626         bool "Default csd_lock_wait() debuggi << 
1627         depends on CSD_LOCK_WAIT_DEBUG        << 
1628         depends on 64BIT                      << 
1629         default n                             << 
1630         help                                  << 
1631           This option causes the csdlock_debu << 
1632           default to 1 (basic debugging) inst << 
1633                                               << 
1634 endmenu # lock debugging                         1260 endmenu # lock debugging
1635                                                  1261 
1636 config TRACE_IRQFLAGS                            1262 config TRACE_IRQFLAGS
1637         depends on TRACE_IRQFLAGS_SUPPORT     << 
1638         bool                                     1263         bool
1639         help                                     1264         help
1640           Enables hooks to interrupt enabling    1265           Enables hooks to interrupt enabling and disabling for
1641           either tracing or lock debugging.      1266           either tracing or lock debugging.
1642                                                  1267 
1643 config TRACE_IRQFLAGS_NMI                     << 
1644         def_bool y                            << 
1645         depends on TRACE_IRQFLAGS             << 
1646         depends on TRACE_IRQFLAGS_NMI_SUPPORT << 
1647                                               << 
1648 config NMI_CHECK_CPU                          << 
1649         bool "Debugging for CPUs failing to r << 
1650         depends on DEBUG_KERNEL               << 
1651         depends on X86                        << 
1652         default n                             << 
1653         help                                  << 
1654           Enables debug prints when a CPU fai << 
1655           backtrace NMI.  These prints provid << 
1656           might legitimately be failing to re << 
1657           is offline of if ignore_nmis is set << 
1658                                               << 
1659 config DEBUG_IRQFLAGS                         << 
1660         bool "Debug IRQ flag manipulation"    << 
1661         help                                  << 
1662           Enables checks for potentially unsa << 
1663           interrupts, such as calling raw_loc << 
1664           are enabled.                        << 
1665                                               << 
1666 config STACKTRACE                                1268 config STACKTRACE
1667         bool "Stack backtrace support"           1269         bool "Stack backtrace support"
1668         depends on STACKTRACE_SUPPORT            1270         depends on STACKTRACE_SUPPORT
1669         help                                     1271         help
1670           This option causes the kernel to cr    1272           This option causes the kernel to create a /proc/pid/stack for
1671           every process, showing its current     1273           every process, showing its current stack trace.
1672           It is also used by various kernel d    1274           It is also used by various kernel debugging features that require
1673           stack trace generation.                1275           stack trace generation.
1674                                                  1276 
1675 config WARN_ALL_UNSEEDED_RANDOM                  1277 config WARN_ALL_UNSEEDED_RANDOM
1676         bool "Warn for all uses of unseeded r    1278         bool "Warn for all uses of unseeded randomness"
1677         default n                                1279         default n
1678         help                                     1280         help
1679           Some parts of the kernel contain bu    1281           Some parts of the kernel contain bugs relating to their use of
1680           cryptographically secure random num    1282           cryptographically secure random numbers before it's actually possible
1681           to generate those numbers securely.    1283           to generate those numbers securely. This setting ensures that these
1682           flaws don't go unnoticed, by enabli    1284           flaws don't go unnoticed, by enabling a message, should this ever
1683           occur. This will allow people with     1285           occur. This will allow people with obscure setups to know when things
1684           are going wrong, so that they might    1286           are going wrong, so that they might contact developers about fixing
1685           it.                                    1287           it.
1686                                                  1288 
1687           Unfortunately, on some models of so    1289           Unfortunately, on some models of some architectures getting
1688           a fully seeded CRNG is extremely di    1290           a fully seeded CRNG is extremely difficult, and so this can
1689           result in dmesg getting spammed for    1291           result in dmesg getting spammed for a surprisingly long
1690           time.  This is really bad from a se    1292           time.  This is really bad from a security perspective, and
1691           so architecture maintainers really     1293           so architecture maintainers really need to do what they can
1692           to get the CRNG seeded sooner after    1294           to get the CRNG seeded sooner after the system is booted.
1693           However, since users cannot do anyt    1295           However, since users cannot do anything actionable to
1694           address this, by default this optio !! 1296           address this, by default the kernel will issue only a single
                                                   >> 1297           warning for the first use of unseeded randomness.
1695                                                  1298 
1696           Say Y here if you want to receive w    1299           Say Y here if you want to receive warnings for all uses of
1697           unseeded randomness.  This will be     1300           unseeded randomness.  This will be of use primarily for
1698           those developers interested in impr    1301           those developers interested in improving the security of
1699           Linux kernels running on their arch    1302           Linux kernels running on their architecture (or
1700           subarchitecture).                      1303           subarchitecture).
1701                                                  1304 
1702 config DEBUG_KOBJECT                             1305 config DEBUG_KOBJECT
1703         bool "kobject debugging"                 1306         bool "kobject debugging"
1704         depends on DEBUG_KERNEL                  1307         depends on DEBUG_KERNEL
1705         help                                     1308         help
1706           If you say Y here, some extra kobje    1309           If you say Y here, some extra kobject debugging messages will be sent
1707           to the syslog.                         1310           to the syslog.
1708                                                  1311 
1709 config DEBUG_KOBJECT_RELEASE                     1312 config DEBUG_KOBJECT_RELEASE
1710         bool "kobject release debugging"         1313         bool "kobject release debugging"
1711         depends on DEBUG_OBJECTS_TIMERS          1314         depends on DEBUG_OBJECTS_TIMERS
1712         help                                     1315         help
1713           kobjects are reference counted obje    1316           kobjects are reference counted objects.  This means that their
1714           last reference count put is not pre    1317           last reference count put is not predictable, and the kobject can
1715           live on past the point at which a d !! 1318           live on past the point at which a driver decides to drop it's
1716           initial reference to the kobject ga    1319           initial reference to the kobject gained on allocation.  An
1717           example of this would be a struct d    1320           example of this would be a struct device which has just been
1718           unregistered.                          1321           unregistered.
1719                                                  1322 
1720           However, some buggy drivers assume     1323           However, some buggy drivers assume that after such an operation,
1721           the memory backing the kobject can     1324           the memory backing the kobject can be immediately freed.  This
1722           goes completely against the princip    1325           goes completely against the principles of a refcounted object.
1723                                                  1326 
1724           If you say Y here, the kernel will     1327           If you say Y here, the kernel will delay the release of kobjects
1725           on the last reference count to impr    1328           on the last reference count to improve the visibility of this
1726           kind of kobject release bug.           1329           kind of kobject release bug.
1727                                                  1330 
1728 config HAVE_DEBUG_BUGVERBOSE                     1331 config HAVE_DEBUG_BUGVERBOSE
1729         bool                                     1332         bool
1730                                                  1333 
1731 menu "Debug kernel data structures"           !! 1334 config DEBUG_BUGVERBOSE
                                                   >> 1335         bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
                                                   >> 1336         depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
                                                   >> 1337         default y
                                                   >> 1338         help
                                                   >> 1339           Say Y here to make BUG() panics output the file name and line number
                                                   >> 1340           of the BUG call as well as the EIP and oops trace.  This aids
                                                   >> 1341           debugging but costs about 70-100K of memory.
1732                                                  1342 
1733 config DEBUG_LIST                                1343 config DEBUG_LIST
1734         bool "Debug linked list manipulation"    1344         bool "Debug linked list manipulation"
1735         depends on DEBUG_KERNEL               !! 1345         depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1736         select LIST_HARDENED                  << 
1737         help                                     1346         help
1738           Enable this to turn on extended che !! 1347           Enable this to turn on extended checks in the linked-list
1739           routines.                           !! 1348           walking routines.
1740                                               << 
1741           This option trades better quality e << 
1742           is more suitable for kernel debuggi << 
1743           you should only enable CONFIG_LIST_ << 
1744                                                  1349 
1745           If unsure, say N.                      1350           If unsure, say N.
1746                                                  1351 
1747 config DEBUG_PLIST                            !! 1352 config DEBUG_PI_LIST
1748         bool "Debug priority linked list mani    1353         bool "Debug priority linked list manipulation"
1749         depends on DEBUG_KERNEL                  1354         depends on DEBUG_KERNEL
1750         help                                     1355         help
1751           Enable this to turn on extended che    1356           Enable this to turn on extended checks in the priority-ordered
1752           linked-list (plist) walking routine    1357           linked-list (plist) walking routines.  This checks the entire
1753           list multiple times during each man    1358           list multiple times during each manipulation.
1754                                                  1359 
1755           If unsure, say N.                      1360           If unsure, say N.
1756                                                  1361 
1757 config DEBUG_SG                                  1362 config DEBUG_SG
1758         bool "Debug SG table operations"         1363         bool "Debug SG table operations"
1759         depends on DEBUG_KERNEL                  1364         depends on DEBUG_KERNEL
1760         help                                     1365         help
1761           Enable this to turn on checks on sc    1366           Enable this to turn on checks on scatter-gather tables. This can
1762           help find problems with drivers tha    1367           help find problems with drivers that do not properly initialize
1763           their sg tables.                       1368           their sg tables.
1764                                                  1369 
1765           If unsure, say N.                      1370           If unsure, say N.
1766                                                  1371 
1767 config DEBUG_NOTIFIERS                           1372 config DEBUG_NOTIFIERS
1768         bool "Debug notifier call chains"        1373         bool "Debug notifier call chains"
1769         depends on DEBUG_KERNEL                  1374         depends on DEBUG_KERNEL
1770         help                                     1375         help
1771           Enable this to turn on sanity check    1376           Enable this to turn on sanity checking for notifier call chains.
1772           This is most useful for kernel deve    1377           This is most useful for kernel developers to make sure that
1773           modules properly unregister themsel    1378           modules properly unregister themselves from notifier chains.
1774           This is a relatively cheap check bu    1379           This is a relatively cheap check but if you care about maximum
1775           performance, say N.                    1380           performance, say N.
1776                                                  1381 
1777 config DEBUG_CLOSURES                         !! 1382 config DEBUG_CREDENTIALS
1778         bool "Debug closures (bcache async wi !! 1383         bool "Debug credential management"
1779         depends on CLOSURES                   << 
1780         select DEBUG_FS                       << 
1781         help                                  << 
1782           Keeps all active closures in a link << 
1783           interface to list them, which makes << 
1784           operations that get stuck.          << 
1785                                               << 
1786 config DEBUG_MAPLE_TREE                       << 
1787         bool "Debug maple trees"              << 
1788         depends on DEBUG_KERNEL                  1384         depends on DEBUG_KERNEL
1789         help                                     1385         help
1790           Enable maple tree debugging informa !! 1386           Enable this to turn on some debug checking for credential
                                                   >> 1387           management.  The additional code keeps track of the number of
                                                   >> 1388           pointers from task_structs to any given cred struct, and checks to
                                                   >> 1389           see that this number never exceeds the usage count of the cred
                                                   >> 1390           struct.
1791                                                  1391 
1792           If unsure, say N.                   !! 1392           Furthermore, if SELinux is enabled, this also checks that the
                                                   >> 1393           security pointer in the cred struct is never seen to be invalid.
1793                                                  1394 
1794 endmenu                                       !! 1395           If unsure, say N.
1795                                                  1396 
1796 source "kernel/rcu/Kconfig.debug"                1397 source "kernel/rcu/Kconfig.debug"
1797                                                  1398 
1798 config DEBUG_WQ_FORCE_RR_CPU                     1399 config DEBUG_WQ_FORCE_RR_CPU
1799         bool "Force round-robin CPU selection    1400         bool "Force round-robin CPU selection for unbound work items"
1800         depends on DEBUG_KERNEL                  1401         depends on DEBUG_KERNEL
1801         default n                                1402         default n
1802         help                                     1403         help
1803           Workqueue used to implicitly guaran    1404           Workqueue used to implicitly guarantee that work items queued
1804           without explicit CPU specified are     1405           without explicit CPU specified are put on the local CPU.  This
1805           guarantee is no longer true and whi    1406           guarantee is no longer true and while local CPU is still
1806           preferred work items may be put on     1407           preferred work items may be put on foreign CPUs.  Kernel
1807           parameter "workqueue.debug_force_rr    1408           parameter "workqueue.debug_force_rr_cpu" is added to force
1808           round-robin CPU selection to flush     1409           round-robin CPU selection to flush out usages which depend on the
1809           now broken guarantee.  This config     1410           now broken guarantee.  This config option enables the debug
1810           feature by default.  When enabled,     1411           feature by default.  When enabled, memory and cache locality will
1811           be impacted.                           1412           be impacted.
1812                                                  1413 
                                                   >> 1414 config DEBUG_BLOCK_EXT_DEVT
                                                   >> 1415         bool "Force extended block device numbers and spread them"
                                                   >> 1416         depends on DEBUG_KERNEL
                                                   >> 1417         depends on BLOCK
                                                   >> 1418         default n
                                                   >> 1419         help
                                                   >> 1420           BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
                                                   >> 1421           SOME DISTRIBUTIONS.  DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
                                                   >> 1422           YOU ARE DOING.  Distros, please enable this and fix whatever
                                                   >> 1423           is broken.
                                                   >> 1424 
                                                   >> 1425           Conventionally, block device numbers are allocated from
                                                   >> 1426           predetermined contiguous area.  However, extended block area
                                                   >> 1427           may introduce non-contiguous block device numbers.  This
                                                   >> 1428           option forces most block device numbers to be allocated from
                                                   >> 1429           the extended space and spreads them to discover kernel or
                                                   >> 1430           userland code paths which assume predetermined contiguous
                                                   >> 1431           device number allocation.
                                                   >> 1432 
                                                   >> 1433           Note that turning on this debug option shuffles all the
                                                   >> 1434           device numbers for all IDE and SCSI devices including libata
                                                   >> 1435           ones, so root partition specified using device number
                                                   >> 1436           directly (via rdev or root=MAJ:MIN) won't work anymore.
                                                   >> 1437           Textual device names (root=/dev/sdXn) will continue to work.
                                                   >> 1438 
                                                   >> 1439           Say N if you are unsure.
                                                   >> 1440 
1813 config CPU_HOTPLUG_STATE_CONTROL                 1441 config CPU_HOTPLUG_STATE_CONTROL
1814         bool "Enable CPU hotplug state contro    1442         bool "Enable CPU hotplug state control"
1815         depends on DEBUG_KERNEL                  1443         depends on DEBUG_KERNEL
1816         depends on HOTPLUG_CPU                   1444         depends on HOTPLUG_CPU
1817         default n                                1445         default n
1818         help                                     1446         help
1819           Allows to write steps between "offl    1447           Allows to write steps between "offline" and "online" to the CPUs
1820           sysfs target file so states can be     1448           sysfs target file so states can be stepped granular. This is a debug
1821           option for now as the hotplug machi    1449           option for now as the hotplug machinery cannot be stopped and
1822           restarted at arbitrary points yet.     1450           restarted at arbitrary points yet.
1823                                                  1451 
1824           Say N if your are unsure.              1452           Say N if your are unsure.
1825                                                  1453 
1826 config LATENCYTOP                             << 
1827         bool "Latency measuring infrastructur << 
1828         depends on DEBUG_KERNEL               << 
1829         depends on STACKTRACE_SUPPORT         << 
1830         depends on PROC_FS                    << 
1831         depends on FRAME_POINTER || MIPS || P << 
1832         select KALLSYMS                       << 
1833         select KALLSYMS_ALL                   << 
1834         select STACKTRACE                     << 
1835         select SCHEDSTATS                     << 
1836         help                                  << 
1837           Enable this option if you want to u << 
1838           to find out which userspace is bloc << 
1839                                               << 
1840 config DEBUG_CGROUP_REF                       << 
1841         bool "Disable inlining of cgroup css  << 
1842         depends on DEBUG_KERNEL               << 
1843         depends on CGROUPS                    << 
1844         depends on KPROBES                    << 
1845         default n                             << 
1846         help                                  << 
1847           Force cgroup css reference count fu << 
1848           that they can be kprobed for debugg << 
1849                                               << 
1850 source "kernel/trace/Kconfig"                 << 
1851                                               << 
1852 config PROVIDE_OHCI1394_DMA_INIT              << 
1853         bool "Remote debugging over FireWire  << 
1854         depends on PCI && X86                 << 
1855         help                                  << 
1856           If you want to debug problems which << 
1857           on boot and the crashing machine ha << 
1858           this feature to remotely access the << 
1859           over FireWire. This employs remote  << 
1860           specification which is now the stan << 
1861                                               << 
1862           With remote DMA, you can monitor th << 
1863           firescope and access all memory bel << 
1864           Even controlling a kernel debugger  << 
1865                                               << 
1866           Usage:                              << 
1867                                               << 
1868           If ohci1394_dma=early is used as bo << 
1869           all OHCI1394 controllers which are  << 
1870                                               << 
1871           As all changes to the FireWire bus  << 
1872           devices cause a bus reset and there << 
1873           devices, be sure to have the cable  << 
1874           the debugging host before booting t << 
1875                                               << 
1876           This code (~1k) is freed after boot << 
1877           in charge of the OHCI-1394 controll << 
1878                                               << 
1879           See Documentation/core-api/debuggin << 
1880                                               << 
1881 source "samples/Kconfig"                      << 
1882                                               << 
1883 config ARCH_HAS_DEVMEM_IS_ALLOWED             << 
1884         bool                                  << 
1885                                               << 
1886 config STRICT_DEVMEM                          << 
1887         bool "Filter access to /dev/mem"      << 
1888         depends on MMU && DEVMEM              << 
1889         depends on ARCH_HAS_DEVMEM_IS_ALLOWED << 
1890         default y if PPC || X86 || ARM64      << 
1891         help                                  << 
1892           If this option is disabled, you all << 
1893           of memory, including kernel and use << 
1894           access to this is obviously disastr << 
1895           be used by people debugging the ker << 
1896           enabled, even in this case there ar << 
1897           use due to the cache aliasing requi << 
1898                                               << 
1899           If this option is switched on, and  << 
1900           file only allows userspace access t << 
1901           data regions.  This is sufficient f << 
1902           users of /dev/mem.                  << 
1903                                               << 
1904           If in doubt, say Y.                 << 
1905                                               << 
1906 config IO_STRICT_DEVMEM                       << 
1907         bool "Filter I/O access to /dev/mem"  << 
1908         depends on STRICT_DEVMEM              << 
1909         help                                  << 
1910           If this option is disabled, you all << 
1911           io-memory regardless of whether a d << 
1912           range.  Accidental access to this i << 
1913           specific access can be used by peop << 
1914                                               << 
1915           If this option is switched on, the  << 
1916           userspace access to *idle* io-memor << 
1917           may break traditional users of /dev << 
1918           if the driver using a given range c << 
1919                                               << 
1920           If in doubt, say Y.                 << 
1921                                               << 
1922 menu "$(SRCARCH) Debugging"                   << 
1923                                               << 
1924 source "arch/$(SRCARCH)/Kconfig.debug"        << 
1925                                               << 
1926 endmenu                                       << 
1927                                               << 
1928 menu "Kernel Testing and Coverage"            << 
1929                                               << 
1930 source "lib/kunit/Kconfig"                    << 
1931                                               << 
1932 config NOTIFIER_ERROR_INJECTION                  1454 config NOTIFIER_ERROR_INJECTION
1933         tristate "Notifier error injection"      1455         tristate "Notifier error injection"
1934         depends on DEBUG_KERNEL                  1456         depends on DEBUG_KERNEL
1935         select DEBUG_FS                          1457         select DEBUG_FS
1936         help                                     1458         help
1937           This option provides the ability to    1459           This option provides the ability to inject artificial errors to
1938           specified notifier chain callbacks.    1460           specified notifier chain callbacks. It is useful to test the error
1939           handling of notifier call chain fai    1461           handling of notifier call chain failures.
1940                                                  1462 
1941           Say N if unsure.                       1463           Say N if unsure.
1942                                                  1464 
1943 config PM_NOTIFIER_ERROR_INJECT                  1465 config PM_NOTIFIER_ERROR_INJECT
1944         tristate "PM notifier error injection    1466         tristate "PM notifier error injection module"
1945         depends on PM && NOTIFIER_ERROR_INJEC    1467         depends on PM && NOTIFIER_ERROR_INJECTION
1946         default m if PM_DEBUG                    1468         default m if PM_DEBUG
1947         help                                     1469         help
1948           This option provides the ability to    1470           This option provides the ability to inject artificial errors to
1949           PM notifier chain callbacks.  It is    1471           PM notifier chain callbacks.  It is controlled through debugfs
1950           interface /sys/kernel/debug/notifie    1472           interface /sys/kernel/debug/notifier-error-inject/pm
1951                                                  1473 
1952           If the notifier call chain should b    1474           If the notifier call chain should be failed with some events
1953           notified, write the error code to "    1475           notified, write the error code to "actions/<notifier event>/error".
1954                                                  1476 
1955           Example: Inject PM suspend error (-    1477           Example: Inject PM suspend error (-12 = -ENOMEM)
1956                                                  1478 
1957           # cd /sys/kernel/debug/notifier-err    1479           # cd /sys/kernel/debug/notifier-error-inject/pm/
1958           # echo -12 > actions/PM_SUSPEND_PRE    1480           # echo -12 > actions/PM_SUSPEND_PREPARE/error
1959           # echo mem > /sys/power/state          1481           # echo mem > /sys/power/state
1960           bash: echo: write error: Cannot all    1482           bash: echo: write error: Cannot allocate memory
1961                                                  1483 
1962           To compile this code as a module, c    1484           To compile this code as a module, choose M here: the module will
1963           be called pm-notifier-error-inject.    1485           be called pm-notifier-error-inject.
1964                                                  1486 
1965           If unsure, say N.                      1487           If unsure, say N.
1966                                                  1488 
1967 config OF_RECONFIG_NOTIFIER_ERROR_INJECT         1489 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1968         tristate "OF reconfig notifier error     1490         tristate "OF reconfig notifier error injection module"
1969         depends on OF_DYNAMIC && NOTIFIER_ERR    1491         depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1970         help                                     1492         help
1971           This option provides the ability to    1493           This option provides the ability to inject artificial errors to
1972           OF reconfig notifier chain callback    1494           OF reconfig notifier chain callbacks.  It is controlled
1973           through debugfs interface under        1495           through debugfs interface under
1974           /sys/kernel/debug/notifier-error-in    1496           /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1975                                                  1497 
1976           If the notifier call chain should b    1498           If the notifier call chain should be failed with some events
1977           notified, write the error code to "    1499           notified, write the error code to "actions/<notifier event>/error".
1978                                                  1500 
1979           To compile this code as a module, c    1501           To compile this code as a module, choose M here: the module will
1980           be called of-reconfig-notifier-erro    1502           be called of-reconfig-notifier-error-inject.
1981                                                  1503 
1982           If unsure, say N.                      1504           If unsure, say N.
1983                                                  1505 
1984 config NETDEV_NOTIFIER_ERROR_INJECT              1506 config NETDEV_NOTIFIER_ERROR_INJECT
1985         tristate "Netdev notifier error injec    1507         tristate "Netdev notifier error injection module"
1986         depends on NET && NOTIFIER_ERROR_INJE    1508         depends on NET && NOTIFIER_ERROR_INJECTION
1987         help                                     1509         help
1988           This option provides the ability to    1510           This option provides the ability to inject artificial errors to
1989           netdevice notifier chain callbacks.    1511           netdevice notifier chain callbacks.  It is controlled through debugfs
1990           interface /sys/kernel/debug/notifie    1512           interface /sys/kernel/debug/notifier-error-inject/netdev
1991                                                  1513 
1992           If the notifier call chain should b    1514           If the notifier call chain should be failed with some events
1993           notified, write the error code to "    1515           notified, write the error code to "actions/<notifier event>/error".
1994                                                  1516 
1995           Example: Inject netdevice mtu chang    1517           Example: Inject netdevice mtu change error (-22 = -EINVAL)
1996                                                  1518 
1997           # cd /sys/kernel/debug/notifier-err    1519           # cd /sys/kernel/debug/notifier-error-inject/netdev
1998           # echo -22 > actions/NETDEV_CHANGEM    1520           # echo -22 > actions/NETDEV_CHANGEMTU/error
1999           # ip link set eth0 mtu 1024            1521           # ip link set eth0 mtu 1024
2000           RTNETLINK answers: Invalid argument    1522           RTNETLINK answers: Invalid argument
2001                                                  1523 
2002           To compile this code as a module, c    1524           To compile this code as a module, choose M here: the module will
2003           be called netdev-notifier-error-inj    1525           be called netdev-notifier-error-inject.
2004                                                  1526 
2005           If unsure, say N.                      1527           If unsure, say N.
2006                                                  1528 
2007 config FUNCTION_ERROR_INJECTION                  1529 config FUNCTION_ERROR_INJECTION
2008         bool "Fault-injections of functions"  !! 1530         def_bool y
2009         depends on HAVE_FUNCTION_ERROR_INJECT    1531         depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
2010         help                                  << 
2011           Add fault injections into various f << 
2012           ALLOW_ERROR_INJECTION() in the kern << 
2013           value of these functions. This is u << 
2014                                               << 
2015           If unsure, say N                    << 
2016                                                  1532 
2017 config FAULT_INJECTION                           1533 config FAULT_INJECTION
2018         bool "Fault-injection framework"         1534         bool "Fault-injection framework"
2019         depends on DEBUG_KERNEL                  1535         depends on DEBUG_KERNEL
2020         help                                     1536         help
2021           Provide fault-injection framework.     1537           Provide fault-injection framework.
2022           For more details, see Documentation    1538           For more details, see Documentation/fault-injection/.
2023                                                  1539 
2024 config FAILSLAB                                  1540 config FAILSLAB
2025         bool "Fault-injection capability for     1541         bool "Fault-injection capability for kmalloc"
2026         depends on FAULT_INJECTION               1542         depends on FAULT_INJECTION
                                                   >> 1543         depends on SLAB || SLUB
2027         help                                     1544         help
2028           Provide fault-injection capability     1545           Provide fault-injection capability for kmalloc.
2029                                                  1546 
2030 config FAIL_PAGE_ALLOC                           1547 config FAIL_PAGE_ALLOC
2031         bool "Fault-injection capability for  !! 1548         bool "Fault-injection capabilitiy for alloc_pages()"
2032         depends on FAULT_INJECTION               1549         depends on FAULT_INJECTION
2033         help                                     1550         help
2034           Provide fault-injection capability     1551           Provide fault-injection capability for alloc_pages().
2035                                                  1552 
2036 config FAULT_INJECTION_USERCOPY               << 
2037         bool "Fault injection capability for  << 
2038         depends on FAULT_INJECTION            << 
2039         help                                  << 
2040           Provides fault-injection capability << 
2041           in usercopy functions (copy_from_us << 
2042                                               << 
2043 config FAIL_MAKE_REQUEST                         1553 config FAIL_MAKE_REQUEST
2044         bool "Fault-injection capability for     1554         bool "Fault-injection capability for disk IO"
2045         depends on FAULT_INJECTION && BLOCK      1555         depends on FAULT_INJECTION && BLOCK
2046         help                                     1556         help
2047           Provide fault-injection capability     1557           Provide fault-injection capability for disk IO.
2048                                                  1558 
2049 config FAIL_IO_TIMEOUT                           1559 config FAIL_IO_TIMEOUT
2050         bool "Fault-injection capability for     1560         bool "Fault-injection capability for faking disk interrupts"
2051         depends on FAULT_INJECTION && BLOCK      1561         depends on FAULT_INJECTION && BLOCK
2052         help                                     1562         help
2053           Provide fault-injection capability     1563           Provide fault-injection capability on end IO handling. This
2054           will make the block layer "forget"     1564           will make the block layer "forget" an interrupt as configured,
2055           thus exercising the error handling.    1565           thus exercising the error handling.
2056                                                  1566 
2057           Only works with drivers that use th    1567           Only works with drivers that use the generic timeout handling,
2058           for others it won't do anything.    !! 1568           for others it wont do anything.
2059                                                  1569 
2060 config FAIL_FUTEX                                1570 config FAIL_FUTEX
2061         bool "Fault-injection capability for     1571         bool "Fault-injection capability for futexes"
2062         select DEBUG_FS                          1572         select DEBUG_FS
2063         depends on FAULT_INJECTION && FUTEX      1573         depends on FAULT_INJECTION && FUTEX
2064         help                                     1574         help
2065           Provide fault-injection capability     1575           Provide fault-injection capability for futexes.
2066                                                  1576 
2067 config FAULT_INJECTION_DEBUG_FS                  1577 config FAULT_INJECTION_DEBUG_FS
2068         bool "Debugfs entries for fault-injec    1578         bool "Debugfs entries for fault-injection capabilities"
2069         depends on FAULT_INJECTION && SYSFS &    1579         depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2070         help                                     1580         help
2071           Enable configuration of fault-injec    1581           Enable configuration of fault-injection capabilities via debugfs.
2072                                                  1582 
2073 config FAIL_FUNCTION                             1583 config FAIL_FUNCTION
2074         bool "Fault-injection capability for     1584         bool "Fault-injection capability for functions"
2075         depends on FAULT_INJECTION_DEBUG_FS &    1585         depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2076         help                                     1586         help
2077           Provide function-based fault-inject    1587           Provide function-based fault-injection capability.
2078           This will allow you to override a s    1588           This will allow you to override a specific function with a return
2079           with given return value. As a resul    1589           with given return value. As a result, function caller will see
2080           an error value and have to handle i    1590           an error value and have to handle it. This is useful to test the
2081           error handling in various subsystem    1591           error handling in various subsystems.
2082                                                  1592 
2083 config FAIL_MMC_REQUEST                          1593 config FAIL_MMC_REQUEST
2084         bool "Fault-injection capability for     1594         bool "Fault-injection capability for MMC IO"
2085         depends on FAULT_INJECTION_DEBUG_FS &    1595         depends on FAULT_INJECTION_DEBUG_FS && MMC
2086         help                                     1596         help
2087           Provide fault-injection capability     1597           Provide fault-injection capability for MMC IO.
2088           This will make the mmc core return     1598           This will make the mmc core return data errors. This is
2089           useful to test the error handling i    1599           useful to test the error handling in the mmc block device
2090           and to test how the mmc host driver    1600           and to test how the mmc host driver handles retries from
2091           the block device.                      1601           the block device.
2092                                                  1602 
2093 config FAIL_SUNRPC                            << 
2094         bool "Fault-injection capability for  << 
2095         depends on FAULT_INJECTION_DEBUG_FS & << 
2096         help                                  << 
2097           Provide fault-injection capability  << 
2098           its consumers.                      << 
2099                                               << 
2100 config FAULT_INJECTION_CONFIGFS               << 
2101         bool "Configfs interface for fault-in << 
2102         depends on FAULT_INJECTION            << 
2103         select CONFIGFS_FS                    << 
2104         help                                  << 
2105           This option allows configfs-based d << 
2106           fault-injection via configfs.  Each << 
2107           fault-injection can be made visible << 
2108           configfs group.                     << 
2109                                               << 
2110                                               << 
2111 config FAULT_INJECTION_STACKTRACE_FILTER         1603 config FAULT_INJECTION_STACKTRACE_FILTER
2112         bool "stacktrace filter for fault-inj    1604         bool "stacktrace filter for fault-injection capabilities"
2113         depends on FAULT_INJECTION            !! 1605         depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2114         depends on (FAULT_INJECTION_DEBUG_FS  !! 1606         depends on !X86_64
2115         select STACKTRACE                        1607         select STACKTRACE
2116         depends on FRAME_POINTER || MIPS || P !! 1608         select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
2117         help                                     1609         help
2118           Provide stacktrace filter for fault    1610           Provide stacktrace filter for fault-injection capabilities
2119                                                  1611 
2120 config ARCH_HAS_KCOV                          !! 1612 config LATENCYTOP
2121         bool                                  !! 1613         bool "Latency measuring infrastructure"
                                                   >> 1614         depends on DEBUG_KERNEL
                                                   >> 1615         depends on STACKTRACE_SUPPORT
                                                   >> 1616         depends on PROC_FS
                                                   >> 1617         select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
                                                   >> 1618         select KALLSYMS
                                                   >> 1619         select KALLSYMS_ALL
                                                   >> 1620         select STACKTRACE
                                                   >> 1621         select SCHEDSTATS
                                                   >> 1622         select SCHED_DEBUG
2122         help                                     1623         help
2123           An architecture should select this  !! 1624           Enable this option if you want to use the LatencyTOP tool
2124           build and run with CONFIG_KCOV. Thi !! 1625           to find out which userspace is blocking on what kernel operations.
2125           disabling instrumentation for some  << 
2126                                               << 
2127 config CC_HAS_SANCOV_TRACE_PC                 << 
2128         def_bool $(cc-option,-fsanitize-cover << 
2129                                                  1626 
                                                   >> 1627 source "kernel/trace/Kconfig"
2130                                                  1628 
2131 config KCOV                                   !! 1629 config PROVIDE_OHCI1394_DMA_INIT
2132         bool "Code coverage for fuzzing"      !! 1630         bool "Remote debugging over FireWire early on boot"
2133         depends on ARCH_HAS_KCOV              !! 1631         depends on PCI && X86
2134         depends on CC_HAS_SANCOV_TRACE_PC ||  << 
2135         depends on !ARCH_WANTS_NO_INSTR || HA << 
2136                    GCC_VERSION >= 120000 || C << 
2137         select DEBUG_FS                       << 
2138         select GCC_PLUGIN_SANCOV if !CC_HAS_S << 
2139         select OBJTOOL if HAVE_NOINSTR_HACK   << 
2140         help                                     1632         help
2141           KCOV exposes kernel code coverage i !! 1633           If you want to debug problems which hang or crash the kernel early
2142           for coverage-guided fuzzing (random !! 1634           on boot and the crashing machine has a FireWire port, you can use
                                                   >> 1635           this feature to remotely access the memory of the crashed machine
                                                   >> 1636           over FireWire. This employs remote DMA as part of the OHCI1394
                                                   >> 1637           specification which is now the standard for FireWire controllers.
2143                                                  1638 
2144           For more details, see Documentation !! 1639           With remote DMA, you can monitor the printk buffer remotely using
                                                   >> 1640           firescope and access all memory below 4GB using fireproxy from gdb.
                                                   >> 1641           Even controlling a kernel debugger is possible using remote DMA.
2145                                                  1642 
2146 config KCOV_ENABLE_COMPARISONS                !! 1643           Usage:
2147         bool "Enable comparison operands coll << 
2148         depends on KCOV                       << 
2149         depends on $(cc-option,-fsanitize-cov << 
2150         help                                  << 
2151           KCOV also exposes operands of every << 
2152           code along with operand sizes and P << 
2153           These operands can be used by fuzzi << 
2154           of fuzzing coverage.                << 
2155                                                  1644 
2156 config KCOV_INSTRUMENT_ALL                    !! 1645           If ohci1394_dma=early is used as boot parameter, it will initialize
2157         bool "Instrument all code by default" !! 1646           all OHCI1394 controllers which are found in the PCI config space.
2158         depends on KCOV                       << 
2159         default y                             << 
2160         help                                  << 
2161           If you are doing generic system cal << 
2162           then you will want to instrument th << 
2163           say y here. If you are doing more t << 
2164           filesystem fuzzing with AFL) then y << 
2165           for more specific subsets of files, << 
2166                                                  1647 
2167 config KCOV_IRQ_AREA_SIZE                     !! 1648           As all changes to the FireWire bus such as enabling and disabling
2168         hex "Size of interrupt coverage colle !! 1649           devices cause a bus reset and thereby disable remote DMA for all
2169         depends on KCOV                       !! 1650           devices, be sure to have the cable plugged and FireWire enabled on
2170         default 0x40000                       !! 1651           the debugging host before booting the debug target for debugging.
2171         help                                  << 
2172           KCOV uses preallocated per-cpu area << 
2173           soft interrupts. This specifies the << 
2174           number of unsigned long words.      << 
2175                                                  1652 
2176 menuconfig RUNTIME_TESTING_MENU               !! 1653           This code (~1k) is freed after boot. By then, the firewire stack
2177         bool "Runtime Testing"                !! 1654           in charge of the OHCI-1394 controllers should be used instead.
2178         default y                             << 
2179                                                  1655 
2180 if RUNTIME_TESTING_MENU                       !! 1656           See Documentation/debugging-via-ohci1394.txt for more information.
2181                                                  1657 
2182 config TEST_DHRY                              !! 1658 config DMA_API_DEBUG
2183         tristate "Dhrystone benchmark test"   !! 1659         bool "Enable debugging of DMA-API usage"
                                                   >> 1660         select NEED_DMA_MAP_STATE
2184         help                                     1661         help
2185           Enable this to include the Dhryston !! 1662           Enable this option to debug the use of the DMA API by device drivers.
2186           calculates the number of Dhrystones !! 1663           With this option you will be able to detect common bugs in device
2187           DMIPS (Dhrystone MIPS) obtained whe !! 1664           drivers like double-freeing of DMA mappings or freeing mappings that
2188           by 1757 (the number of Dhrystones p !! 1665           were never allocated.
2189           11/780, nominally a 1 MIPS machine) << 
2190                                               << 
2191           To run the benchmark, it needs to b << 
2192           the kernel command line (when built << 
2193           built-in or modular).               << 
2194                                               << 
2195           Run once during kernel boot:        << 
2196                                               << 
2197               test_dhry.run                   << 
2198                                                  1666 
2199           Set number of iterations from kerne !! 1667           This also attempts to catch cases where a page owned by DMA is
                                                   >> 1668           accessed by the cpu in a way that could cause data corruption.  For
                                                   >> 1669           example, this enables cow_user_page() to check that the source page is
                                                   >> 1670           not undergoing DMA.
2200                                                  1671 
2201               test_dhry.iterations=<n>        !! 1672           This option causes a performance degradation.  Use only if you want to
                                                   >> 1673           debug device drivers and dma interactions.
2202                                                  1674 
2203           Set number of iterations from users !! 1675           If unsure, say N.
2204                                               << 
2205               echo <n> > /sys/module/test_dhr << 
2206                                                  1676 
2207           Trigger manual run from userspace:  !! 1677 config DMA_API_DEBUG_SG
                                                   >> 1678         bool "Debug DMA scatter-gather usage"
                                                   >> 1679         default y
                                                   >> 1680         depends on DMA_API_DEBUG
                                                   >> 1681         help
                                                   >> 1682           Perform extra checking that callers of dma_map_sg() have respected the
                                                   >> 1683           appropriate segment length/boundary limits for the given device when
                                                   >> 1684           preparing DMA scatterlists.
                                                   >> 1685 
                                                   >> 1686           This is particularly likely to have been overlooked in cases where the
                                                   >> 1687           dma_map_sg() API is used for general bulk mapping of pages rather than
                                                   >> 1688           preparing literal scatter-gather descriptors, where there is a risk of
                                                   >> 1689           unexpected behaviour from DMA API implementations if the scatterlist
                                                   >> 1690           is technically out-of-spec.
2208                                                  1691 
2209               echo y > /sys/module/test_dhry/ !! 1692           If unsure, say N.
2210                                                  1693 
2211           If the number of iterations is <= 0 !! 1694 menuconfig RUNTIME_TESTING_MENU
2212           number of iterations (test runs for !! 1695         bool "Runtime Testing"
2213           This process takes ca. 4s.          !! 1696         def_bool y
2214                                                  1697 
2215           If unsure, say N.                   !! 1698 if RUNTIME_TESTING_MENU
2216                                                  1699 
2217 config LKDTM                                     1700 config LKDTM
2218         tristate "Linux Kernel Dump Test Tool    1701         tristate "Linux Kernel Dump Test Tool Module"
2219         depends on DEBUG_FS                      1702         depends on DEBUG_FS
                                                   >> 1703         depends on BLOCK
2220         help                                     1704         help
2221         This module enables testing of the di    1705         This module enables testing of the different dumping mechanisms by
2222         inducing system failures at predefine    1706         inducing system failures at predefined crash points.
2223         If you don't need it: say N              1707         If you don't need it: say N
2224         Choose M here to compile this code as    1708         Choose M here to compile this code as a module. The module will be
2225         called lkdtm.                            1709         called lkdtm.
2226                                                  1710 
2227         Documentation on how to use the modul    1711         Documentation on how to use the module can be found in
2228         Documentation/fault-injection/provoke !! 1712         Documentation/fault-injection/provoke-crashes.txt
2229                                               << 
2230 config CPUMASK_KUNIT_TEST                     << 
2231         tristate "KUnit test for cpumask" if  << 
2232         depends on KUNIT                      << 
2233         default KUNIT_ALL_TESTS               << 
2234         help                                  << 
2235           Enable to turn on cpumask tests, ru << 
2236                                               << 
2237           For more information on KUnit and u << 
2238           to the KUnit documentation in Docum << 
2239                                               << 
2240           If unsure, say N.                   << 
2241                                                  1713 
2242 config TEST_LIST_SORT                            1714 config TEST_LIST_SORT
2243         tristate "Linked list sorting test" i !! 1715         tristate "Linked list sorting test"
2244         depends on KUNIT                      << 
2245         default KUNIT_ALL_TESTS               << 
2246         help                                  << 
2247           Enable this to turn on 'list_sort() << 
2248           executed only once during system bo << 
2249           or at module load time.             << 
2250                                               << 
2251           If unsure, say N.                   << 
2252                                               << 
2253 config TEST_MIN_HEAP                          << 
2254         tristate "Min heap test"              << 
2255         depends on DEBUG_KERNEL || m             1716         depends on DEBUG_KERNEL || m
2256         help                                     1717         help
2257           Enable this to turn on min heap fun !! 1718           Enable this to turn on 'list_sort()' function test. This test is
2258           executed only once during system bo    1719           executed only once during system boot (so affects only boot time),
2259           or at module load time.                1720           or at module load time.
2260                                                  1721 
2261           If unsure, say N.                      1722           If unsure, say N.
2262                                                  1723 
2263 config TEST_SORT                                 1724 config TEST_SORT
2264         tristate "Array-based sort test" if ! !! 1725         tristate "Array-based sort test"
2265         depends on KUNIT                      << 
2266         default KUNIT_ALL_TESTS               << 
2267         help                                  << 
2268           This option enables the self-test f << 
2269           or at module load time.             << 
2270                                               << 
2271           If unsure, say N.                   << 
2272                                               << 
2273 config TEST_DIV64                             << 
2274         tristate "64bit/32bit division and mo << 
2275         depends on DEBUG_KERNEL || m             1726         depends on DEBUG_KERNEL || m
2276         help                                     1727         help
2277           Enable this to turn on 'do_div()' f !! 1728           This option enables the self-test function of 'sort()' at boot,
2278           executed only once during system bo << 
2279           or at module load time.                1729           or at module load time.
2280                                                  1730 
2281           If unsure, say N.                      1731           If unsure, say N.
2282                                                  1732 
2283 config TEST_IOV_ITER                          << 
2284         tristate "Test iov_iter operation" if << 
2285         depends on KUNIT                      << 
2286         depends on MMU                        << 
2287         default KUNIT_ALL_TESTS               << 
2288         help                                  << 
2289           Enable this to turn on testing of t << 
2290           (iov_iter). This test is executed o << 
2291           affects only boot time), or at modu << 
2292                                               << 
2293           If unsure, say N.                   << 
2294                                               << 
2295 config KPROBES_SANITY_TEST                       1733 config KPROBES_SANITY_TEST
2296         tristate "Kprobes sanity tests" if !K !! 1734         bool "Kprobes sanity tests"
2297         depends on DEBUG_KERNEL                  1735         depends on DEBUG_KERNEL
2298         depends on KPROBES                       1736         depends on KPROBES
2299         depends on KUNIT                      << 
2300         select STACKTRACE if ARCH_CORRECT_STA << 
2301         default KUNIT_ALL_TESTS               << 
2302         help                                     1737         help
2303           This option provides for testing ba    1738           This option provides for testing basic kprobes functionality on
2304           boot. Samples of kprobe and kretpro    1739           boot. Samples of kprobe and kretprobe are inserted and
2305           verified for functionality.            1740           verified for functionality.
2306                                                  1741 
2307           Say N if you are unsure.               1742           Say N if you are unsure.
2308                                                  1743 
2309 config FPROBE_SANITY_TEST                     << 
2310         bool "Self test for fprobe"           << 
2311         depends on DEBUG_KERNEL               << 
2312         depends on FPROBE                     << 
2313         depends on KUNIT=y                    << 
2314         help                                  << 
2315           This option will enable testing the << 
2316           A series of tests are made to verif << 
2317           properly.                           << 
2318                                               << 
2319           Say N if you are unsure.            << 
2320                                               << 
2321 config BACKTRACE_SELF_TEST                       1744 config BACKTRACE_SELF_TEST
2322         tristate "Self test for the backtrace    1745         tristate "Self test for the backtrace code"
2323         depends on DEBUG_KERNEL                  1746         depends on DEBUG_KERNEL
2324         help                                     1747         help
2325           This option provides a kernel modul    1748           This option provides a kernel module that can be used to test
2326           the kernel stack backtrace code. Th    1749           the kernel stack backtrace code. This option is not useful
2327           for distributions or general kernel    1750           for distributions or general kernels, but only for kernel
2328           developers working on architecture     1751           developers working on architecture code.
2329                                                  1752 
2330           Note that if you want to also test     1753           Note that if you want to also test saved backtraces, you will
2331           have to enable STACKTRACE as well.     1754           have to enable STACKTRACE as well.
2332                                                  1755 
2333           Say N if you are unsure.               1756           Say N if you are unsure.
2334                                                  1757 
2335 config TEST_REF_TRACKER                       << 
2336         tristate "Self test for reference tra << 
2337         depends on DEBUG_KERNEL && STACKTRACE << 
2338         select REF_TRACKER                    << 
2339         help                                  << 
2340           This option provides a kernel modul << 
2341           using reference tracker infrastruct << 
2342                                               << 
2343           Say N if you are unsure.            << 
2344                                               << 
2345 config RBTREE_TEST                               1758 config RBTREE_TEST
2346         tristate "Red-Black tree test"           1759         tristate "Red-Black tree test"
2347         depends on DEBUG_KERNEL                  1760         depends on DEBUG_KERNEL
2348         help                                     1761         help
2349           A benchmark measuring the performan    1762           A benchmark measuring the performance of the rbtree library.
2350           Also includes rbtree invariant chec    1763           Also includes rbtree invariant checks.
2351                                                  1764 
2352 config REED_SOLOMON_TEST                      << 
2353         tristate "Reed-Solomon library test"  << 
2354         depends on DEBUG_KERNEL || m          << 
2355         select REED_SOLOMON                   << 
2356         select REED_SOLOMON_ENC16             << 
2357         select REED_SOLOMON_DEC16             << 
2358         help                                  << 
2359           This option enables the self-test f << 
2360           or at module load time.             << 
2361                                               << 
2362           If unsure, say N.                   << 
2363                                               << 
2364 config INTERVAL_TREE_TEST                        1765 config INTERVAL_TREE_TEST
2365         tristate "Interval tree test"            1766         tristate "Interval tree test"
2366         depends on DEBUG_KERNEL                  1767         depends on DEBUG_KERNEL
2367         select INTERVAL_TREE                     1768         select INTERVAL_TREE
2368         help                                     1769         help
2369           A benchmark measuring the performan    1770           A benchmark measuring the performance of the interval tree library
2370                                                  1771 
2371 config PERCPU_TEST                               1772 config PERCPU_TEST
2372         tristate "Per cpu operations test"       1773         tristate "Per cpu operations test"
2373         depends on m && DEBUG_KERNEL             1774         depends on m && DEBUG_KERNEL
2374         help                                     1775         help
2375           Enable this option to build test mo    1776           Enable this option to build test module which validates per-cpu
2376           operations.                            1777           operations.
2377                                                  1778 
2378           If unsure, say N.                      1779           If unsure, say N.
2379                                                  1780 
2380 config ATOMIC64_SELFTEST                         1781 config ATOMIC64_SELFTEST
2381         tristate "Perform an atomic64_t self-    1782         tristate "Perform an atomic64_t self-test"
2382         help                                     1783         help
2383           Enable this option to test the atom    1784           Enable this option to test the atomic64_t functions at boot or
2384           at module load time.                   1785           at module load time.
2385                                                  1786 
2386           If unsure, say N.                      1787           If unsure, say N.
2387                                                  1788 
2388 config ASYNC_RAID6_TEST                          1789 config ASYNC_RAID6_TEST
2389         tristate "Self test for hardware acce    1790         tristate "Self test for hardware accelerated raid6 recovery"
2390         depends on ASYNC_RAID6_RECOV             1791         depends on ASYNC_RAID6_RECOV
2391         select ASYNC_MEMCPY                      1792         select ASYNC_MEMCPY
2392         help                                  !! 1793         ---help---
2393           This is a one-shot self test that p    1794           This is a one-shot self test that permutes through the
2394           recovery of all the possible two di    1795           recovery of all the possible two disk failure scenarios for a
2395           N-disk array.  Recovery is performe    1796           N-disk array.  Recovery is performed with the asynchronous
2396           raid6 recovery routines, and will o    1797           raid6 recovery routines, and will optionally use an offload
2397           engine if one is available.            1798           engine if one is available.
2398                                                  1799 
2399           If unsure, say N.                      1800           If unsure, say N.
2400                                                  1801 
2401 config TEST_HEXDUMP                              1802 config TEST_HEXDUMP
2402         tristate "Test functions located in t    1803         tristate "Test functions located in the hexdump module at runtime"
2403                                                  1804 
2404 config STRING_KUNIT_TEST                      !! 1805 config TEST_STRING_HELPERS
2405         tristate "KUnit test string functions !! 1806         tristate "Test functions located in the string_helpers module at runtime"
2406         depends on KUNIT                      << 
2407         default KUNIT_ALL_TESTS               << 
2408                                               << 
2409 config STRING_HELPERS_KUNIT_TEST              << 
2410         tristate "KUnit test string helpers a << 
2411         depends on KUNIT                      << 
2412         default KUNIT_ALL_TESTS               << 
2413                                                  1807 
2414 config TEST_KSTRTOX                              1808 config TEST_KSTRTOX
2415         tristate "Test kstrto*() family of fu    1809         tristate "Test kstrto*() family of functions at runtime"
2416                                                  1810 
2417 config TEST_PRINTF                               1811 config TEST_PRINTF
2418         tristate "Test printf() family of fun    1812         tristate "Test printf() family of functions at runtime"
2419                                                  1813 
2420 config TEST_SCANF                             << 
2421         tristate "Test scanf() family of func << 
2422                                               << 
2423 config TEST_BITMAP                               1814 config TEST_BITMAP
2424         tristate "Test bitmap_*() family of f    1815         tristate "Test bitmap_*() family of functions at runtime"
2425         help                                     1816         help
2426           Enable this option to test the bitm    1817           Enable this option to test the bitmap functions at boot.
2427                                                  1818 
2428           If unsure, say N.                      1819           If unsure, say N.
2429                                                  1820 
                                                   >> 1821 config TEST_BITFIELD
                                                   >> 1822         tristate "Test bitfield functions at runtime"
                                                   >> 1823         help
                                                   >> 1824           Enable this option to test the bitfield functions at boot.
                                                   >> 1825 
                                                   >> 1826           If unsure, say N.
                                                   >> 1827 
2430 config TEST_UUID                                 1828 config TEST_UUID
2431         tristate "Test functions located in t    1829         tristate "Test functions located in the uuid module at runtime"
2432                                                  1830 
2433 config TEST_XARRAY                               1831 config TEST_XARRAY
2434         tristate "Test the XArray code at run    1832         tristate "Test the XArray code at runtime"
2435                                                  1833 
2436 config TEST_MAPLE_TREE                        !! 1834 config TEST_OVERFLOW
2437         tristate "Test the Maple Tree code at !! 1835         tristate "Test check_*_overflow() functions at runtime"
2438         help                                  << 
2439           Enable this option to test the mapl << 
2440           when the module is loaded. Enable " << 
2441           more verbose output on failures.    << 
2442                                               << 
2443           If unsure, say N.                   << 
2444                                                  1836 
2445 config TEST_RHASHTABLE                           1837 config TEST_RHASHTABLE
2446         tristate "Perform selftest on resizab    1838         tristate "Perform selftest on resizable hash table"
2447         help                                     1839         help
2448           Enable this option to test the rhas    1840           Enable this option to test the rhashtable functions at boot.
2449                                                  1841 
2450           If unsure, say N.                      1842           If unsure, say N.
2451                                                  1843 
                                                   >> 1844 config TEST_HASH
                                                   >> 1845         tristate "Perform selftest on hash functions"
                                                   >> 1846         help
                                                   >> 1847           Enable this option to test the kernel's integer (<linux/hash.h>),
                                                   >> 1848           string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
                                                   >> 1849           hash functions on boot (or module load).
                                                   >> 1850 
                                                   >> 1851           This is intended to help people writing architecture-specific
                                                   >> 1852           optimized versions.  If unsure, say N.
                                                   >> 1853 
2452 config TEST_IDA                                  1854 config TEST_IDA
2453         tristate "Perform selftest on IDA fun    1855         tristate "Perform selftest on IDA functions"
2454                                                  1856 
2455 config TEST_PARMAN                               1857 config TEST_PARMAN
2456         tristate "Perform selftest on priorit    1858         tristate "Perform selftest on priority array manager"
2457         depends on PARMAN                        1859         depends on PARMAN
2458         help                                     1860         help
2459           Enable this option to test priority    1861           Enable this option to test priority array manager on boot
2460           (or module load).                      1862           (or module load).
2461                                                  1863 
2462           If unsure, say N.                      1864           If unsure, say N.
2463                                                  1865 
2464 config TEST_IRQ_TIMINGS                       << 
2465         bool "IRQ timings selftest"           << 
2466         depends on IRQ_TIMINGS                << 
2467         help                                  << 
2468           Enable this option to test the irq  << 
2469                                               << 
2470           If unsure, say N.                   << 
2471                                               << 
2472 config TEST_LKM                                  1866 config TEST_LKM
2473         tristate "Test module loading with 'h    1867         tristate "Test module loading with 'hello world' module"
2474         depends on m                             1868         depends on m
2475         help                                     1869         help
2476           This builds the "test_module" modul    1870           This builds the "test_module" module that emits "Hello, world"
2477           on printk when loaded. It is design    1871           on printk when loaded. It is designed to be used for basic
2478           evaluation of the module loading su    1872           evaluation of the module loading subsystem (for example when
2479           validating module verification). It    1873           validating module verification). It lacks any extra dependencies,
2480           and will not normally be loaded by     1874           and will not normally be loaded by the system unless explicitly
2481           requested by name.                     1875           requested by name.
2482                                                  1876 
2483           If unsure, say N.                      1877           If unsure, say N.
2484                                                  1878 
2485 config TEST_BITOPS                            !! 1879 config TEST_USER_COPY
2486         tristate "Test module for compilation !! 1880         tristate "Test user/kernel boundary protections"
2487         help                                  << 
2488           This builds the "test_bitops" modul << 
2489           TEST_LKM module except that it does << 
2490           set/clear_bit macros and get_count_ << 
2491           no compiler warnings from C=1 spars << 
2492           compilations. It has no dependencie << 
2493           explicitly requested by name.  for  << 
2494                                               << 
2495           If unsure, say N.                   << 
2496                                               << 
2497 config TEST_VMALLOC                           << 
2498         tristate "Test module for stress/perf << 
2499         default n                             << 
2500        depends on MMU                         << 
2501         depends on m                             1881         depends on m
2502         help                                     1882         help
2503           This builds the "test_vmalloc" modu !! 1883           This builds the "test_user_copy" module that runs sanity checks
2504           stress and performance analysis. So !! 1884           on the copy_to/from_user infrastructure, making sure basic
2505           subsystem can be evaluated from per !! 1885           user/kernel boundary testing is working. If it fails to load,
2506           of view.                            !! 1886           a regression has been detected in the user/kernel memory boundary
                                                   >> 1887           protections.
2507                                                  1888 
2508           If unsure, say N.                      1889           If unsure, say N.
2509                                                  1890 
2510 config TEST_BPF                                  1891 config TEST_BPF
2511         tristate "Test BPF filter functionali    1892         tristate "Test BPF filter functionality"
2512         depends on m && NET                      1893         depends on m && NET
2513         help                                     1894         help
2514           This builds the "test_bpf" module t    1895           This builds the "test_bpf" module that runs various test vectors
2515           against the BPF interpreter or BPF     1896           against the BPF interpreter or BPF JIT compiler depending on the
2516           current setting. This is in particu    1897           current setting. This is in particular useful for BPF JIT compiler
2517           development, but also to run regres    1898           development, but also to run regression tests against changes in
2518           the interpreter code. It also enabl    1899           the interpreter code. It also enables test stubs for eBPF maps and
2519           verifier used by user space verifie    1900           verifier used by user space verifier testsuite.
2520                                                  1901 
2521           If unsure, say N.                      1902           If unsure, say N.
2522                                                  1903 
2523 config TEST_BLACKHOLE_DEV                     << 
2524         tristate "Test blackhole netdev funct << 
2525         depends on m && NET                   << 
2526         help                                  << 
2527           This builds the "test_blackhole_dev << 
2528           data path through this blackhole ne << 
2529                                               << 
2530           If unsure, say N.                   << 
2531                                               << 
2532 config FIND_BIT_BENCHMARK                        1904 config FIND_BIT_BENCHMARK
2533         tristate "Test find_bit functions"       1905         tristate "Test find_bit functions"
2534         help                                     1906         help
2535           This builds the "test_find_bit" mod    1907           This builds the "test_find_bit" module that measure find_*_bit()
2536           functions performance.                 1908           functions performance.
2537                                                  1909 
2538           If unsure, say N.                      1910           If unsure, say N.
2539                                                  1911 
2540 config TEST_FIRMWARE                             1912 config TEST_FIRMWARE
2541         tristate "Test firmware loading via u    1913         tristate "Test firmware loading via userspace interface"
2542         depends on FW_LOADER                     1914         depends on FW_LOADER
2543         help                                     1915         help
2544           This builds the "test_firmware" mod    1916           This builds the "test_firmware" module that creates a userspace
2545           interface for testing firmware load    1917           interface for testing firmware loading. This can be used to
2546           control the triggering of firmware     1918           control the triggering of firmware loading without needing an
2547           actual firmware-using device. The c    1919           actual firmware-using device. The contents can be rechecked by
2548           userspace.                             1920           userspace.
2549                                                  1921 
2550           If unsure, say N.                      1922           If unsure, say N.
2551                                                  1923 
2552 config TEST_SYSCTL                               1924 config TEST_SYSCTL
2553         tristate "sysctl test driver"            1925         tristate "sysctl test driver"
2554         depends on PROC_SYSCTL                   1926         depends on PROC_SYSCTL
2555         help                                     1927         help
2556           This builds the "test_sysctl" modul    1928           This builds the "test_sysctl" module. This driver enables to test the
2557           proc sysctl interfaces available to    1929           proc sysctl interfaces available to drivers safely without affecting
2558           production knobs which might alter     1930           production knobs which might alter system functionality.
2559                                                  1931 
2560           If unsure, say N.                      1932           If unsure, say N.
2561                                                  1933 
2562 config BITFIELD_KUNIT                         << 
2563         tristate "KUnit test bitfield functio << 
2564         depends on KUNIT                      << 
2565         default KUNIT_ALL_TESTS               << 
2566         help                                  << 
2567           Enable this option to test the bitf << 
2568                                               << 
2569           KUnit tests run during boot and out << 
2570           in TAP format (http://testanything. << 
2571           running the KUnit test harness, and << 
2572           production build.                   << 
2573                                               << 
2574           For more information on KUnit and u << 
2575           to the KUnit documentation in Docum << 
2576                                               << 
2577           If unsure, say N.                   << 
2578                                               << 
2579 config CHECKSUM_KUNIT                         << 
2580         tristate "KUnit test checksum functio << 
2581         depends on KUNIT                      << 
2582         default KUNIT_ALL_TESTS               << 
2583         help                                  << 
2584           Enable this option to test the chec << 
2585                                               << 
2586           KUnit tests run during boot and out << 
2587           in TAP format (http://testanything. << 
2588           running the KUnit test harness, and << 
2589           production build.                   << 
2590                                               << 
2591           For more information on KUnit and u << 
2592           to the KUnit documentation in Docum << 
2593                                               << 
2594           If unsure, say N.                   << 
2595                                               << 
2596 config HASH_KUNIT_TEST                        << 
2597         tristate "KUnit Test for integer hash << 
2598         depends on KUNIT                      << 
2599         default KUNIT_ALL_TESTS               << 
2600         help                                  << 
2601           Enable this option to test the kern << 
2602           integer (<linux/hash.h>) hash funct << 
2603                                               << 
2604           KUnit tests run during boot and out << 
2605           in TAP format (https://testanything << 
2606           running the KUnit test harness, and << 
2607           production build.                   << 
2608                                               << 
2609           For more information on KUnit and u << 
2610           to the KUnit documentation in Docum << 
2611                                               << 
2612           This is intended to help people wri << 
2613           optimized versions. If unsure, say  << 
2614                                               << 
2615 config RESOURCE_KUNIT_TEST                    << 
2616         tristate "KUnit test for resource API << 
2617         depends on KUNIT                      << 
2618         default KUNIT_ALL_TESTS               << 
2619         help                                  << 
2620           This builds the resource API unit t << 
2621           Tests the logic of API provided by  << 
2622           For more information on KUnit and u << 
2623           to the KUnit documentation in Docum << 
2624                                               << 
2625           If unsure, say N.                   << 
2626                                               << 
2627 config SYSCTL_KUNIT_TEST                      << 
2628         tristate "KUnit test for sysctl" if ! << 
2629         depends on KUNIT                      << 
2630         default KUNIT_ALL_TESTS               << 
2631         help                                  << 
2632           This builds the proc sysctl unit te << 
2633           Tests the API contract and implemen << 
2634           For more information on KUnit and u << 
2635           to the KUnit documentation in Docum << 
2636                                               << 
2637           If unsure, say N.                   << 
2638                                               << 
2639 config LIST_KUNIT_TEST                        << 
2640         tristate "KUnit Test for Kernel Linke << 
2641         depends on KUNIT                      << 
2642         default KUNIT_ALL_TESTS               << 
2643         help                                  << 
2644           This builds the linked list KUnit t << 
2645           It tests that the API and basic fun << 
2646           and associated macros.              << 
2647                                               << 
2648           KUnit tests run during boot and out << 
2649           in TAP format (https://testanything << 
2650           running the KUnit test harness, and << 
2651           production build.                   << 
2652                                               << 
2653           For more information on KUnit and u << 
2654           to the KUnit documentation in Docum << 
2655                                               << 
2656           If unsure, say N.                   << 
2657                                               << 
2658 config HASHTABLE_KUNIT_TEST                   << 
2659         tristate "KUnit Test for Kernel Hasht << 
2660         depends on KUNIT                      << 
2661         default KUNIT_ALL_TESTS               << 
2662         help                                  << 
2663           This builds the hashtable KUnit tes << 
2664           It tests the basic functionality of << 
2665           include/linux/hashtable.h. For more << 
2666           unit tests in general please refer  << 
2667           in Documentation/dev-tools/kunit/.  << 
2668                                               << 
2669           If unsure, say N.                   << 
2670                                               << 
2671 config LINEAR_RANGES_TEST                     << 
2672         tristate "KUnit test for linear_range << 
2673         depends on KUNIT                      << 
2674         select LINEAR_RANGES                  << 
2675         help                                  << 
2676           This builds the linear_ranges unit  << 
2677           Tests the linear_ranges logic corre << 
2678           For more information on KUnit and u << 
2679           to the KUnit documentation in Docum << 
2680                                               << 
2681           If unsure, say N.                   << 
2682                                               << 
2683 config CMDLINE_KUNIT_TEST                     << 
2684         tristate "KUnit test for cmdline API" << 
2685         depends on KUNIT                      << 
2686         default KUNIT_ALL_TESTS               << 
2687         help                                  << 
2688           This builds the cmdline API unit te << 
2689           Tests the logic of API provided by  << 
2690           For more information on KUnit and u << 
2691           to the KUnit documentation in Docum << 
2692                                               << 
2693           If unsure, say N.                   << 
2694                                               << 
2695 config BITS_TEST                              << 
2696         tristate "KUnit test for bits.h" if ! << 
2697         depends on KUNIT                      << 
2698         default KUNIT_ALL_TESTS               << 
2699         help                                  << 
2700           This builds the bits unit test.     << 
2701           Tests the logic of macros defined i << 
2702           For more information on KUnit and u << 
2703           to the KUnit documentation in Docum << 
2704                                               << 
2705           If unsure, say N.                   << 
2706                                               << 
2707 config SLUB_KUNIT_TEST                        << 
2708         tristate "KUnit test for SLUB cache e << 
2709         depends on SLUB_DEBUG && KUNIT        << 
2710         default KUNIT_ALL_TESTS               << 
2711         help                                  << 
2712           This builds SLUB allocator unit tes << 
2713           Tests SLUB cache debugging function << 
2714           For more information on KUnit and u << 
2715           to the KUnit documentation in Docum << 
2716                                               << 
2717           If unsure, say N.                   << 
2718                                               << 
2719 config RATIONAL_KUNIT_TEST                    << 
2720         tristate "KUnit test for rational.c"  << 
2721         depends on KUNIT && RATIONAL          << 
2722         default KUNIT_ALL_TESTS               << 
2723         help                                  << 
2724           This builds the rational math unit  << 
2725           For more information on KUnit and u << 
2726           to the KUnit documentation in Docum << 
2727                                               << 
2728           If unsure, say N.                   << 
2729                                               << 
2730 config MEMCPY_KUNIT_TEST                      << 
2731         tristate "Test memcpy(), memmove(), a << 
2732         depends on KUNIT                      << 
2733         default KUNIT_ALL_TESTS               << 
2734         help                                  << 
2735           Builds unit tests for memcpy(), mem << 
2736           For more information on KUnit and u << 
2737           to the KUnit documentation in Docum << 
2738                                               << 
2739           If unsure, say N.                   << 
2740                                               << 
2741 config IS_SIGNED_TYPE_KUNIT_TEST              << 
2742         tristate "Test is_signed_type() macro << 
2743         depends on KUNIT                      << 
2744         default KUNIT_ALL_TESTS               << 
2745         help                                  << 
2746           Builds unit tests for the is_signed << 
2747                                               << 
2748           For more information on KUnit and u << 
2749           to the KUnit documentation in Docum << 
2750                                               << 
2751           If unsure, say N.                   << 
2752                                               << 
2753 config OVERFLOW_KUNIT_TEST                    << 
2754         tristate "Test check_*_overflow() fun << 
2755         depends on KUNIT                      << 
2756         default KUNIT_ALL_TESTS               << 
2757         help                                  << 
2758           Builds unit tests for the check_*_o << 
2759           related functions.                  << 
2760                                               << 
2761           For more information on KUnit and u << 
2762           to the KUnit documentation in Docum << 
2763                                               << 
2764           If unsure, say N.                   << 
2765                                               << 
2766 config STACKINIT_KUNIT_TEST                   << 
2767         tristate "Test level of stack variabl << 
2768         depends on KUNIT                      << 
2769         default KUNIT_ALL_TESTS               << 
2770         help                                  << 
2771           Test if the kernel is zero-initiali << 
2772           padding. Coverage is controlled by  << 
2773           CONFIG_INIT_STACK_ALL_PATTERN, CONF << 
2774           CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFI << 
2775           or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYR << 
2776                                               << 
2777 config FORTIFY_KUNIT_TEST                     << 
2778         tristate "Test fortified str*() and m << 
2779         depends on KUNIT                      << 
2780         default KUNIT_ALL_TESTS               << 
2781         help                                  << 
2782           Builds unit tests for checking inte << 
2783           by the str*() and mem*() family of  << 
2784           traps of FORTIFY_SOURCE, see LKDTM' << 
2785                                               << 
2786 config HW_BREAKPOINT_KUNIT_TEST               << 
2787         bool "Test hw_breakpoint constraints  << 
2788         depends on HAVE_HW_BREAKPOINT         << 
2789         depends on KUNIT=y                    << 
2790         default KUNIT_ALL_TESTS               << 
2791         help                                  << 
2792           Tests for hw_breakpoint constraints << 
2793                                               << 
2794           If unsure, say N.                   << 
2795                                               << 
2796 config SIPHASH_KUNIT_TEST                     << 
2797         tristate "Perform selftest on siphash << 
2798         depends on KUNIT                      << 
2799         default KUNIT_ALL_TESTS               << 
2800         help                                  << 
2801           Enable this option to test the kern << 
2802           functions on boot (or module load). << 
2803                                               << 
2804           This is intended to help people wri << 
2805           optimized versions.  If unsure, say << 
2806                                               << 
2807 config USERCOPY_KUNIT_TEST                    << 
2808         tristate "KUnit Test for user/kernel  << 
2809         depends on KUNIT                      << 
2810         default KUNIT_ALL_TESTS               << 
2811         help                                  << 
2812           This builds the "usercopy_kunit" mo << 
2813           on the copy_to/from_user infrastruc << 
2814           user/kernel boundary testing is wor << 
2815                                               << 
2816 config TEST_UDELAY                               1934 config TEST_UDELAY
2817         tristate "udelay test driver"            1935         tristate "udelay test driver"
2818         help                                     1936         help
2819           This builds the "udelay_test" modul    1937           This builds the "udelay_test" module that helps to make sure
2820           that udelay() is working properly.     1938           that udelay() is working properly.
2821                                                  1939 
2822           If unsure, say N.                      1940           If unsure, say N.
2823                                                  1941 
2824 config TEST_STATIC_KEYS                          1942 config TEST_STATIC_KEYS
2825         tristate "Test static keys"              1943         tristate "Test static keys"
2826         depends on m                             1944         depends on m
2827         help                                     1945         help
2828           Test the static key interfaces.        1946           Test the static key interfaces.
2829                                                  1947 
2830           If unsure, say N.                      1948           If unsure, say N.
2831                                                  1949 
2832 config TEST_DYNAMIC_DEBUG                     << 
2833         tristate "Test DYNAMIC_DEBUG"         << 
2834         depends on DYNAMIC_DEBUG              << 
2835         help                                  << 
2836           This module registers a tracer call << 
2837           pr_debugs in a 'do_debugging' funct << 
2838           enablements, calls the function, an << 
2839                                               << 
2840           If unsure, say N.                   << 
2841                                               << 
2842 config TEST_KMOD                                 1950 config TEST_KMOD
2843         tristate "kmod stress tester"            1951         tristate "kmod stress tester"
2844         depends on m                             1952         depends on m
                                                   >> 1953         depends on BLOCK && (64BIT || LBDAF)      # for XFS, BTRFS
2845         depends on NETDEVICES && NET_CORE &&     1954         depends on NETDEVICES && NET_CORE && INET # for TUN
2846         depends on BLOCK                         1955         depends on BLOCK
2847         depends on PAGE_SIZE_LESS_THAN_256KB  << 
2848         select TEST_LKM                          1956         select TEST_LKM
2849         select XFS_FS                            1957         select XFS_FS
2850         select TUN                               1958         select TUN
2851         select BTRFS_FS                          1959         select BTRFS_FS
2852         help                                     1960         help
2853           Test the kernel's module loading me    1961           Test the kernel's module loading mechanism: kmod. kmod implements
2854           support to load modules using the L    1962           support to load modules using the Linux kernel's usermode helper.
2855           This test provides a series of test    1963           This test provides a series of tests against kmod.
2856                                                  1964 
2857           Although technically you can either    1965           Although technically you can either build test_kmod as a module or
2858           into the kernel we disallow buildin    1966           into the kernel we disallow building it into the kernel since
2859           it stress tests request_module() an    1967           it stress tests request_module() and this will very likely cause
2860           some issues by taking over precious    1968           some issues by taking over precious threads available from other
2861           module load requests, ultimately th    1969           module load requests, ultimately this could be fatal.
2862                                                  1970 
2863           To run tests run:                      1971           To run tests run:
2864                                                  1972 
2865           tools/testing/selftests/kmod/kmod.s    1973           tools/testing/selftests/kmod/kmod.sh --help
2866                                                  1974 
2867           If unsure, say N.                      1975           If unsure, say N.
2868                                                  1976 
2869 config TEST_DEBUG_VIRTUAL                        1977 config TEST_DEBUG_VIRTUAL
2870         tristate "Test CONFIG_DEBUG_VIRTUAL f    1978         tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2871         depends on DEBUG_VIRTUAL                 1979         depends on DEBUG_VIRTUAL
2872         help                                     1980         help
2873           Test the kernel's ability to detect    1981           Test the kernel's ability to detect incorrect calls to
2874           virt_to_phys() done against the non    1982           virt_to_phys() done against the non-linear part of the
2875           kernel's virtual address map.          1983           kernel's virtual address map.
2876                                                  1984 
2877           If unsure, say N.                      1985           If unsure, say N.
2878                                                  1986 
2879 config TEST_MEMCAT_P                             1987 config TEST_MEMCAT_P
2880         tristate "Test memcat_p() helper func    1988         tristate "Test memcat_p() helper function"
2881         help                                     1989         help
2882           Test the memcat_p() helper for corr    1990           Test the memcat_p() helper for correctly merging two
2883           pointer arrays together.               1991           pointer arrays together.
2884                                                  1992 
2885           If unsure, say N.                      1993           If unsure, say N.
2886                                                  1994 
2887 config TEST_OBJAGG                               1995 config TEST_OBJAGG
2888         tristate "Perform selftest on object     1996         tristate "Perform selftest on object aggreration manager"
2889         default n                                1997         default n
2890         depends on OBJAGG                        1998         depends on OBJAGG
2891         help                                     1999         help
2892           Enable this option to test object a    2000           Enable this option to test object aggregation manager on boot
2893           (or module load).                      2001           (or module load).
2894                                                  2002 
2895 config TEST_MEMINIT                           << 
2896         tristate "Test heap/page initializati << 
2897         help                                  << 
2898           Test if the kernel is zero-initiali << 
2899           This can be useful to test init_on_ << 
2900                                               << 
2901           If unsure, say N.                   << 
2902                                               << 
2903 config TEST_HMM                               << 
2904         tristate "Test HMM (Heterogeneous Mem << 
2905         depends on TRANSPARENT_HUGEPAGE       << 
2906         depends on DEVICE_PRIVATE             << 
2907         select HMM_MIRROR                     << 
2908         select MMU_NOTIFIER                   << 
2909         help                                  << 
2910           This is a pseudo device driver sole << 
2911           Say M here if you want to build the << 
2912           Doing so will allow you to run tool << 
2913                                               << 
2914           If unsure, say N.                   << 
2915                                               << 
2916 config TEST_FREE_PAGES                        << 
2917         tristate "Test freeing pages"         << 
2918         help                                  << 
2919           Test that a memory leak does not oc << 
2920           freeing a block of pages and a spec << 
2921           Loading this module is safe if your << 
2922           If the bug is not fixed, it will le << 
2923           probably OOM your system.           << 
2924                                               << 
2925 config TEST_FPU                               << 
2926         tristate "Test floating point operati << 
2927         depends on ARCH_HAS_KERNEL_FPU_SUPPOR << 
2928         help                                  << 
2929           Enable this option to add /sys/kern << 
2930           which will trigger a sequence of fl << 
2931           for self-testing floating point con << 
2932           kernel_fpu_begin().                 << 
2933                                               << 
2934           If unsure, say N.                   << 
2935                                               << 
2936 config TEST_CLOCKSOURCE_WATCHDOG              << 
2937         tristate "Test clocksource watchdog i << 
2938         depends on CLOCKSOURCE_WATCHDOG       << 
2939         help                                  << 
2940           Enable this option to create a kern << 
2941           a test of the clocksource watchdog. << 
2942           via modprobe or insmod in which cas << 
2943           loaded, or it may be built in, in w << 
2944           shortly after boot.                 << 
2945                                               << 
2946           If unsure, say N.                   << 
2947                                               << 
2948 config TEST_OBJPOOL                           << 
2949         tristate "Test module for correctness << 
2950         default n                             << 
2951         depends on m && DEBUG_KERNEL          << 
2952         help                                  << 
2953           This builds the "test_objpool" modu << 
2954           correctness verification and concur << 
2955           allocation and reclamation.         << 
2956                                               << 
2957           If unsure, say N.                      2003           If unsure, say N.
2958                                                  2004 
2959 endif # RUNTIME_TESTING_MENU                     2005 endif # RUNTIME_TESTING_MENU
2960                                                  2006 
2961 config ARCH_USE_MEMTEST                       << 
2962         bool                                  << 
2963         help                                  << 
2964           An architecture should select this  << 
2965           during boot process.                << 
2966                                               << 
2967 config MEMTEST                                   2007 config MEMTEST
2968         bool "Memtest"                           2008         bool "Memtest"
2969         depends on ARCH_USE_MEMTEST           !! 2009         ---help---
2970         help                                  << 
2971           This option adds a kernel parameter    2010           This option adds a kernel parameter 'memtest', which allows memtest
2972           to be set and executed.             !! 2011           to be set.
2973                 memtest=0, mean disabled; --     2012                 memtest=0, mean disabled; -- default
2974                 memtest=1, mean do 1 test pat    2013                 memtest=1, mean do 1 test pattern;
2975                 ...                              2014                 ...
2976                 memtest=17, mean do 17 test p    2015                 memtest=17, mean do 17 test patterns.
2977           If you are unsure how to answer thi    2016           If you are unsure how to answer this question, answer N.
2978                                                  2017 
2979                                               !! 2018 config BUG_ON_DATA_CORRUPTION
2980                                               !! 2019         bool "Trigger a BUG when data corruption is detected"
2981 config HYPERV_TESTING                         !! 2020         select DEBUG_LIST
2982         bool "Microsoft Hyper-V driver testin !! 2021         help
2983         default n                             !! 2022           Select this option if the kernel should BUG when it encounters
2984         depends on HYPERV && DEBUG_FS         !! 2023           data corruption in kernel memory structures when they get checked
2985         help                                  !! 2024           for validity.
2986           Select this option to enable Hyper- << 
2987                                               << 
2988 endmenu # "Kernel Testing and Coverage"       << 
2989                                               << 
2990 menu "Rust hacking"                           << 
2991                                               << 
2992 config RUST_DEBUG_ASSERTIONS                  << 
2993         bool "Debug assertions"               << 
2994         depends on RUST                       << 
2995         help                                  << 
2996           Enables rustc's `-Cdebug-assertions << 
2997                                               << 
2998           This flag lets you turn `cfg(debug_ << 
2999           compilation on or off. This can be  << 
3000           code in development but not in prod << 
3001           the behavior of the standard librar << 
3002                                               << 
3003           Note that this will apply to all Ru << 
3004                                                  2025 
3005           If unsure, say N.                      2026           If unsure, say N.
3006                                                  2027 
3007 config RUST_OVERFLOW_CHECKS                   !! 2028 source "samples/Kconfig"
3008         bool "Overflow checks"                << 
3009         default y                             << 
3010         depends on RUST                       << 
3011         help                                  << 
3012           Enables rustc's `-Coverflow-checks` << 
3013                                               << 
3014           This flag allows you to control the << 
3015           overflow. When overflow-checks are  << 
3016           on overflow.                        << 
3017                                                  2029 
3018           Note that this will apply to all Ru !! 2030 source "lib/Kconfig.kgdb"
3019                                                  2031 
3020           If unsure, say Y.                   !! 2032 source "lib/Kconfig.ubsan"
3021                                                  2033 
3022 config RUST_BUILD_ASSERT_ALLOW                !! 2034 config ARCH_HAS_DEVMEM_IS_ALLOWED
3023         bool "Allow unoptimized build-time as !! 2035         bool
3024         depends on RUST                       << 
3025         help                                  << 
3026           Controls how are `build_error!` and << 
3027                                                  2036 
3028           If calls to them exist in the binar !! 2037 config STRICT_DEVMEM
3029           or that the optimizer failed to ver !! 2038         bool "Filter access to /dev/mem"
                                                   >> 2039         depends on MMU && DEVMEM
                                                   >> 2040         depends on ARCH_HAS_DEVMEM_IS_ALLOWED
                                                   >> 2041         default y if PPC || X86 || ARM64
                                                   >> 2042         ---help---
                                                   >> 2043           If this option is disabled, you allow userspace (root) access to all
                                                   >> 2044           of memory, including kernel and userspace memory. Accidental
                                                   >> 2045           access to this is obviously disastrous, but specific access can
                                                   >> 2046           be used by people debugging the kernel. Note that with PAT support
                                                   >> 2047           enabled, even in this case there are restrictions on /dev/mem
                                                   >> 2048           use due to the cache aliasing requirements.
3030                                                  2049 
3031           This should not happen, thus by def !! 2050           If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
3032           as an escape hatch, you can choose  !! 2051           file only allows userspace access to PCI space and the BIOS code and
3033           and let the check be carried at run !! 2052           data regions.  This is sufficient for dosemu and X and all common
3034           the check fails).                   !! 2053           users of /dev/mem.
3035                                                  2054 
3036           If unsure, say N.                   !! 2055           If in doubt, say Y.
3037                                                  2056 
3038 config RUST_KERNEL_DOCTESTS                   !! 2057 config IO_STRICT_DEVMEM
3039         bool "Doctests for the `kernel` crate !! 2058         bool "Filter I/O access to /dev/mem"
3040         depends on RUST && KUNIT=y            !! 2059         depends on STRICT_DEVMEM
3041         default KUNIT_ALL_TESTS               !! 2060         ---help---
3042         help                                  !! 2061           If this option is disabled, you allow userspace (root) access to all
3043           This builds the documentation tests !! 2062           io-memory regardless of whether a driver is actively using that
3044           as KUnit tests.                     !! 2063           range.  Accidental access to this is obviously disastrous, but
                                                   >> 2064           specific access can be used by people debugging kernel drivers.
3045                                                  2065 
3046           For more information on KUnit and u !! 2066           If this option is switched on, the /dev/mem file only allows
3047           please refer to the KUnit documenta !! 2067           userspace access to *idle* io-memory ranges (see /proc/iomem) This
                                                   >> 2068           may break traditional users of /dev/mem (dosemu, legacy X, etc...)
                                                   >> 2069           if the driver using a given range cannot be disabled.
3048                                                  2070 
3049           If unsure, say N.                   !! 2071           If in doubt, say Y.
3050                                                  2072 
3051 endmenu # "Rust"                              !! 2073 source "arch/$(SRCARCH)/Kconfig.debug"
3052                                                  2074 
3053 endmenu # Kernel hacking                         2075 endmenu # Kernel hacking
                                                      

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