1 # SPDX-License-Identifier: GPL-2.0-only <<
2 menu "Kernel hacking" <<
3 <<
4 menu "printk and dmesg options" 1 menu "printk and dmesg options"
5 2
6 config PRINTK_TIME 3 config PRINTK_TIME
7 bool "Show timing information on print 4 bool "Show timing information on printks"
8 depends on PRINTK 5 depends on PRINTK
9 help 6 help
10 Selecting this option causes time st 7 Selecting this option causes time stamps of the printk()
11 messages to be added to the output o 8 messages to be added to the output of the syslog() system
12 call and at the console. 9 call and at the console.
13 10
14 The timestamp is always recorded int 11 The timestamp is always recorded internally, and exported
15 to /dev/kmsg. This flag just specifi 12 to /dev/kmsg. This flag just specifies if the timestamp should
16 be included, not that the timestamp 13 be included, not that the timestamp is recorded.
17 14
18 The behavior is also controlled by t 15 The behavior is also controlled by the kernel command line
19 parameter printk.time=1. See Documen !! 16 parameter printk.time=1. See Documentation/kernel-parameters.txt
20 <<
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 <<
50 int "Default console loglevel (1-15)" <<
51 range 1 15 <<
52 default "7" <<
53 help <<
54 Default loglevel to determine what w <<
55 <<
56 Setting a default here is equivalent <<
57 the kernel bootargs. loglevel=<x> co <<
58 value is specified here as well. <<
59 <<
60 Note: This does not affect the log l <<
61 usage in the kernel. That is control <<
62 option. <<
63 <<
64 config CONSOLE_LOGLEVEL_QUIET <<
65 int "quiet console loglevel (1-15)" <<
66 range 1 15 <<
67 default "4" <<
68 help <<
69 loglevel to use when "quiet" is pass <<
70 <<
71 When "quiet" is passed on the kernel <<
72 will be used as the loglevel. IOW pa <<
73 equivalent of passing "loglevel=<CON <<
74 17
75 config MESSAGE_LOGLEVEL_DEFAULT 18 config MESSAGE_LOGLEVEL_DEFAULT
76 int "Default message log level (1-7)" 19 int "Default message log level (1-7)"
77 range 1 7 20 range 1 7
78 default "4" 21 default "4"
79 help 22 help
80 Default log level for printk stateme 23 Default log level for printk statements with no specified priority.
81 24
82 This was hard-coded to KERN_WARNING 25 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83 that are auditing their logs closely 26 that are auditing their logs closely may want to set it to a lower
84 priority. 27 priority.
85 28
86 Note: This does not affect what mess <<
87 by default. To change that, use logl <<
88 or pick a different CONSOLE_LOGLEVEL <<
89 <<
90 config BOOT_PRINTK_DELAY 29 config BOOT_PRINTK_DELAY
91 bool "Delay each boot printk message b 30 bool "Delay each boot printk message by N milliseconds"
92 depends on DEBUG_KERNEL && PRINTK && G 31 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
93 help 32 help
94 This build option allows you to read 33 This build option allows you to read kernel boot messages
95 by inserting a short delay after eac 34 by inserting a short delay after each one. The delay is
96 specified in milliseconds on the ker 35 specified in milliseconds on the kernel command line,
97 using "boot_delay=N". 36 using "boot_delay=N".
98 37
99 It is likely that you would also nee 38 It is likely that you would also need to use "lpj=M" to preset
100 the "loops per jiffie" value. 39 the "loops per jiffie" value.
101 See a previous boot log for the "lpj 40 See a previous boot log for the "lpj" value to use for your
102 system, and then set "lpj=M" before 41 system, and then set "lpj=M" before setting "boot_delay=N".
103 NOTE: Using this option may adverse 42 NOTE: Using this option may adversely affect SMP systems.
104 I.e., processors other than the firs 43 I.e., processors other than the first one may not boot up.
105 BOOT_PRINTK_DELAY also may cause LOC 44 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106 what it believes to be lockup condit 45 what it believes to be lockup conditions.
107 46
108 config DYNAMIC_DEBUG 47 config DYNAMIC_DEBUG
109 bool "Enable dynamic printk() support" 48 bool "Enable dynamic printk() support"
110 default n 49 default n
111 depends on PRINTK 50 depends on PRINTK
112 depends on (DEBUG_FS || PROC_FS) !! 51 depends on DEBUG_FS
113 select DYNAMIC_DEBUG_CORE <<
114 help 52 help
115 53
116 Compiles debug level messages into t 54 Compiles debug level messages into the kernel, which would not
117 otherwise be available at runtime. T 55 otherwise be available at runtime. These messages can then be
118 enabled/disabled based on various le 56 enabled/disabled based on various levels of scope - per source file,
119 function, module, format string, and 57 function, module, format string, and line number. This mechanism
120 implicitly compiles in all pr_debug( 58 implicitly compiles in all pr_debug() and dev_dbg() calls, which
121 enlarges the kernel text size by abo 59 enlarges the kernel text size by about 2%.
122 60
123 If a source file is compiled with DE 61 If a source file is compiled with DEBUG flag set, any
124 pr_debug() calls in it are enabled b 62 pr_debug() calls in it are enabled by default, but can be
125 disabled at runtime as below. Note 63 disabled at runtime as below. Note that DEBUG flag is
126 turned on by many CONFIG_*DEBUG* opt 64 turned on by many CONFIG_*DEBUG* options.
127 65
128 Usage: 66 Usage:
129 67
130 Dynamic debugging is controlled via 68 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
131 which is contained in the 'debugfs' !! 69 which is contained in the 'debugfs' filesystem. Thus, the debugfs
132 Thus, the debugfs or procfs filesyst !! 70 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 71 We refer the control file as: <debugfs>/dynamic_debug/control. This
135 file contains a list of the debug st 72 file contains a list of the debug statements that can be enabled. The
136 format for each line of the file is: 73 format for each line of the file is:
137 74
138 filename:lineno [module]functi 75 filename:lineno [module]function flags format
139 76
140 filename : source file of the debug 77 filename : source file of the debug statement
141 lineno : line number of the debug st 78 lineno : line number of the debug statement
142 module : module that contains the de 79 module : module that contains the debug statement
143 function : function that contains th 80 function : function that contains the debug statement
144 flags : '=p' means the line is turne !! 81 flags : '=p' means the line is turned 'on' for printing
145 format : the format used for the deb !! 82 format : the format used for the debug statement
146 83
147 From a live system: 84 From a live system:
148 85
149 nullarbor:~ # cat <debugfs>/dy 86 nullarbor:~ # cat <debugfs>/dynamic_debug/control
150 # filename:lineno [module]func 87 # filename:lineno [module]function flags format
151 fs/aio.c:222 [aio]__put_ioctx 88 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152 fs/aio.c:248 [aio]ioctx_alloc 89 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153 fs/aio.c:1770 [aio]sys_io_canc 90 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154 91
155 Example usage: 92 Example usage:
156 93
157 // enable the message at line 94 // enable the message at line 1603 of file svcsock.c
158 nullarbor:~ # echo -n 'file sv 95 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159 96 <debugfs>/dynamic_debug/control
160 97
161 // enable all the messages in 98 // enable all the messages in file svcsock.c
162 nullarbor:~ # echo -n 'file sv 99 nullarbor:~ # echo -n 'file svcsock.c +p' >
163 100 <debugfs>/dynamic_debug/control
164 101
165 // enable all the messages in 102 // enable all the messages in the NFS server module
166 nullarbor:~ # echo -n 'module 103 nullarbor:~ # echo -n 'module nfsd +p' >
167 104 <debugfs>/dynamic_debug/control
168 105
169 // enable all 12 messages in t 106 // enable all 12 messages in the function svc_process()
170 nullarbor:~ # echo -n 'func sv 107 nullarbor:~ # echo -n 'func svc_process +p' >
171 108 <debugfs>/dynamic_debug/control
172 109
173 // disable all 12 messages in 110 // disable all 12 messages in the function svc_process()
174 nullarbor:~ # echo -n 'func sv 111 nullarbor:~ # echo -n 'func svc_process -p' >
175 112 <debugfs>/dynamic_debug/control
176 113
177 See Documentation/admin-guide/dynami !! 114 See Documentation/dynamic-debug-howto.txt for additional information.
178 information. <<
179 <<
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 <<
208 115
209 endmenu # "printk and dmesg options" 116 endmenu # "printk and dmesg options"
210 117
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 118 menu "Compile-time checks and compiler options"
226 119
227 config DEBUG_INFO 120 config DEBUG_INFO
228 bool !! 121 bool "Compile the kernel with debug info"
>> 122 depends on DEBUG_KERNEL && !COMPILE_TEST
229 help 123 help
230 A kernel debug info option other tha !! 124 If you say Y here the resulting kernel image will include
231 in the "Debug information" choice be !! 125 debugging info resulting in a larger kernel image.
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 <<
244 Selecting something other than "None <<
245 that will include debugging info res <<
246 This adds debug symbols to the kerne 126 This adds debug symbols to the kernel and modules (gcc -g), and
247 is needed if you intend to use kerne 127 is needed if you intend to use kernel crashdump or binary object
248 tools like crash, kgdb, LKCD, gdb, e 128 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
>> 129 Say Y here only if you plan to debug the kernel.
249 130
250 Choose which version of DWARF debug !! 131 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 <<
304 132
305 config DEBUG_INFO_REDUCED 133 config DEBUG_INFO_REDUCED
306 bool "Reduce debugging information" 134 bool "Reduce debugging information"
>> 135 depends on DEBUG_INFO
307 help 136 help
308 If you say Y here gcc is instructed 137 If you say Y here gcc is instructed to generate less debugging
309 information for structure types. Thi 138 information for structure types. This means that tools that
310 need full debugging information (lik 139 need full debugging information (like kgdb or systemtap) won't
311 be happy. But if you merely need deb 140 be happy. But if you merely need debugging information to
312 resolve line numbers there is no los 141 resolve line numbers there is no loss. Advantage is that
313 build directory object sizes shrink 142 build directory object sizes shrink dramatically over a full
314 DEBUG_INFO build and compile times a 143 DEBUG_INFO build and compile times are reduced too.
315 Only works with newer gcc versions. 144 Only works with newer gcc versions.
316 145
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 146 config DEBUG_INFO_SPLIT
358 bool "Produce split debuginfo in .dwo 147 bool "Produce split debuginfo in .dwo files"
359 depends on $(cc-option,-gsplit-dwarf) !! 148 depends on DEBUG_INFO && !FRV
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 149 help
366 Generate debug info into separate .d 150 Generate debug info into separate .dwo files. This significantly
367 reduces the build directory size for 151 reduces the build directory size for builds with DEBUG_INFO,
368 because it stores the information on 152 because it stores the information only once on disk in .dwo
369 files instead of multiple times in o 153 files instead of multiple times in object files and executables.
370 In addition the debug information is 154 In addition the debug information is also compressed.
371 155
372 Requires recent gcc (4.7+) and recen 156 Requires recent gcc (4.7+) and recent gdb/binutils.
373 Any tool that packages or reads debu 157 Any tool that packages or reads debug information would need
374 to know about the .dwo files and inc 158 to know about the .dwo files and include them.
375 Incompatible with older versions of 159 Incompatible with older versions of ccache.
376 160
377 config DEBUG_INFO_BTF !! 161 config DEBUG_INFO_DWARF4
378 bool "Generate BTF type information" !! 162 bool "Generate dwarf4 debuginfo"
379 depends on !DEBUG_INFO_SPLIT && !DEBUG !! 163 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 164 help
415 Generate compact split BTF type info !! 165 Generate dwarf4 debug info. This requires recent versions
416 !! 166 of gcc and gdb. It makes the debug information larger.
417 config MODULE_ALLOW_BTF_MISMATCH !! 167 But it significantly improves the success of resolving
418 bool "Allow loading modules with non-m !! 168 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. <<
426 169
427 config GDB_SCRIPTS 170 config GDB_SCRIPTS
428 bool "Provide GDB scripts for kernel d 171 bool "Provide GDB scripts for kernel debugging"
>> 172 depends on DEBUG_INFO
429 help 173 help
430 This creates the required links to G 174 This creates the required links to GDB helper scripts in the
431 build directory. If you load vmlinux 175 build directory. If you load vmlinux into gdb, the helper
432 scripts will be automatically import 176 scripts will be automatically imported by gdb as well, and
433 additional functions are available t 177 additional functions are available to analyze a Linux kernel
434 instance. See Documentation/dev-tool !! 178 instance. See Documentation/gdb-kernel-debugging.txt for further
435 for further details. !! 179 details.
>> 180
>> 181 config ENABLE_WARN_DEPRECATED
>> 182 bool "Enable __deprecated logic"
>> 183 default y
>> 184 help
>> 185 Enable the __deprecated logic in the kernel build.
>> 186 Disable this to suppress the "warning: 'foo' is deprecated
>> 187 (declared at kernel/power/somefile.c:1234)" messages.
436 188
437 endif # DEBUG_INFO !! 189 config ENABLE_MUST_CHECK
>> 190 bool "Enable __must_check logic"
>> 191 default y
>> 192 help
>> 193 Enable the __must_check logic in the kernel build. Disable this to
>> 194 suppress the "warning: ignoring return value of 'foo', declared with
>> 195 attribute warn_unused_result" messages.
438 196
439 config FRAME_WARN 197 config FRAME_WARN
440 int "Warn for stack frames larger than !! 198 int "Warn for stack frames larger than (needs gcc 4.4)"
441 range 0 8192 199 range 0 8192
442 default 0 if KMSAN <<
443 default 2048 if GCC_PLUGIN_LATENT_ENTR 200 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
444 default 2048 if PARISC <<
445 default 1536 if (!64BIT && XTENSA) <<
446 default 1280 if KASAN && !64BIT <<
447 default 1024 if !64BIT 201 default 1024 if !64BIT
448 default 2048 if 64BIT 202 default 2048 if 64BIT
449 help 203 help
450 Tell the compiler to warn at build t !! 204 Tell gcc to warn at build time for stack frames larger than this.
451 Setting this too low will cause a lo 205 Setting this too low will cause a lot of warnings.
452 Setting it to 0 disables the warning 206 Setting it to 0 disables the warning.
>> 207 Requires gcc 4.4
453 208
454 config STRIP_ASM_SYMS 209 config STRIP_ASM_SYMS
455 bool "Strip assembler-generated symbol 210 bool "Strip assembler-generated symbols during link"
456 default n 211 default n
457 help 212 help
458 Strip internal assembler-generated s 213 Strip internal assembler-generated symbols during a link (symbols
459 that look like '.Lxxx') so they don' 214 that look like '.Lxxx') so they don't pollute the output of
460 get_wchan() and suchlike. 215 get_wchan() and suchlike.
461 216
462 config READABLE_ASM 217 config READABLE_ASM
463 bool "Generate readable assembler code !! 218 bool "Generate readable assembler code"
464 depends on DEBUG_KERNEL !! 219 depends on DEBUG_KERNEL
465 depends on CC_IS_GCC !! 220 help
>> 221 Disable some compiler optimizations that tend to generate human unreadable
>> 222 assembler output. This may make the kernel slightly slower, but it helps
>> 223 to keep kernel developers who have to stare a lot at assembler listings
>> 224 sane.
>> 225
>> 226 config UNUSED_SYMBOLS
>> 227 bool "Enable unused/obsolete exported symbols"
>> 228 default y if X86
>> 229 help
>> 230 Unused but exported symbols make the kernel needlessly bigger. For
>> 231 that reason most of these unused exports will soon be removed. This
>> 232 option is provided temporarily to provide a transition period in case
>> 233 some external kernel module needs one of these symbols anyway. If you
>> 234 encounter such a case in your module, consider if you are actually
>> 235 using the right API. (rationale: since nobody in the kernel is using
>> 236 this in a module, there is a pretty good chance it's actually the
>> 237 wrong interface to use). If you really need the symbol, please send a
>> 238 mail to the linux kernel mailing list mentioning the symbol and why
>> 239 you really need it, and what the merge plan to the mainline kernel for
>> 240 your module is.
>> 241
>> 242 config PAGE_OWNER
>> 243 bool "Track page owner"
>> 244 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
>> 245 select DEBUG_FS
>> 246 select STACKTRACE
>> 247 select STACKDEPOT
>> 248 select PAGE_EXTENSION
466 help 249 help
467 Disable some compiler optimizations !! 250 This keeps track of what call chain is the owner of a page, may
468 assembler output. This may make the !! 251 help to find bare alloc_page(s) leaks. Even if you include this
469 to keep kernel developers who have t !! 252 feature on your build, it is disabled in default. You should pass
470 sane. !! 253 "page_owner=on" to boot parameter in order to enable it. Eats
>> 254 a fair amount of memory if enabled. See tools/vm/page_owner_sort.c
>> 255 for user-space helper.
471 256
472 config HEADERS_INSTALL !! 257 If unsure, say N.
473 bool "Install uapi headers to usr/incl !! 258
>> 259 config DEBUG_FS
>> 260 bool "Debug Filesystem"
>> 261 select SRCU
>> 262 help
>> 263 debugfs is a virtual file system that kernel developers use to put
>> 264 debugging files into. Enable this option to be able to read and
>> 265 write to these files.
>> 266
>> 267 For detailed documentation on the debugfs API, see
>> 268 Documentation/DocBook/filesystems.
>> 269
>> 270 If unsure, say N.
>> 271
>> 272 config HEADERS_CHECK
>> 273 bool "Run 'make headers_check' when building vmlinux"
474 depends on !UML 274 depends on !UML
475 help 275 help
476 This option will install uapi header !! 276 This option will extract the user-visible kernel headers whenever
477 into the usr/include directory for u !! 277 building the kernel, and will run basic sanity checks on them to
478 This is unneeded for building the ke !! 278 ensure that exported files do not attempt to include files which
479 user-space program samples. It is al !! 279 were not exported, etc.
480 as uapi header sanity checks. !! 280
>> 281 If you're making modifications to header files which are
>> 282 relevant for userspace, say 'Y', and check the headers
>> 283 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
>> 284 your build tree), to make sure they're suitable.
481 285
482 config DEBUG_SECTION_MISMATCH 286 config DEBUG_SECTION_MISMATCH
483 bool "Enable full Section mismatch ana 287 bool "Enable full Section mismatch analysis"
484 depends on CC_IS_GCC <<
485 help 288 help
486 The section mismatch analysis checks 289 The section mismatch analysis checks if there are illegal
487 references from one section to anoth 290 references from one section to another section.
488 During linktime or runtime, some sec 291 During linktime or runtime, some sections are dropped;
489 any use of code/data previously in t 292 any use of code/data previously in these sections would
490 most likely result in an oops. 293 most likely result in an oops.
491 In the code, functions and variables 294 In the code, functions and variables are annotated with
492 __init,, etc. (see the full list in 295 __init,, etc. (see the full list in include/linux/init.h),
493 which results in the code/data being 296 which results in the code/data being placed in specific sections.
494 The section mismatch analysis is alw 297 The section mismatch analysis is always performed after a full
495 kernel build, and enabling this opti 298 kernel build, and enabling this option causes the following
496 additional step to occur: !! 299 additional steps to occur:
497 - Add the option -fno-inline-functio 300 - Add the option -fno-inline-functions-called-once to gcc commands.
498 When inlining a function annotated 301 When inlining a function annotated with __init in a non-init
499 function, we would lose the sectio 302 function, we would lose the section information and thus
500 the analysis would not catch the i 303 the analysis would not catch the illegal reference.
501 This option tells gcc to inline le 304 This option tells gcc to inline less (but it does result in
502 a larger kernel). 305 a larger kernel).
>> 306 - Run the section mismatch analysis for each module/built-in.o file.
>> 307 When we run the section mismatch analysis on vmlinux.o, we
>> 308 lose valuable information about where the mismatch was
>> 309 introduced.
>> 310 Running the analysis for each module/built-in.o file
>> 311 tells where the mismatch happens much closer to the
>> 312 source. The drawback is that the same mismatch is
>> 313 reported at least twice.
>> 314 - Enable verbose reporting from modpost in order to help resolve
>> 315 the section mismatches that are reported.
503 316
504 config SECTION_MISMATCH_WARN_ONLY 317 config SECTION_MISMATCH_WARN_ONLY
505 bool "Make section mismatch errors non 318 bool "Make section mismatch errors non-fatal"
506 default y 319 default y
507 help 320 help
508 If you say N here, the build process 321 If you say N here, the build process will fail if there are any
509 section mismatch, instead of just th 322 section mismatch, instead of just throwing warnings.
510 323
511 If unsure, say Y. 324 If unsure, say Y.
512 325
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 # 326 #
527 # Select this config option from the architect 327 # Select this config option from the architecture Kconfig, if it
528 # is preferred to always offer frame pointers 328 # is preferred to always offer frame pointers as a config
529 # option on the architecture (regardless of KE 329 # option on the architecture (regardless of KERNEL_DEBUG):
530 # 330 #
531 config ARCH_WANT_FRAME_POINTERS 331 config ARCH_WANT_FRAME_POINTERS
532 bool 332 bool
>> 333 help
533 334
534 config FRAME_POINTER 335 config FRAME_POINTER
535 bool "Compile the kernel with frame po 336 bool "Compile the kernel with frame pointers"
536 depends on DEBUG_KERNEL && (M68K || UM !! 337 depends on DEBUG_KERNEL && \
>> 338 (CRIS || M68K || FRV || UML || \
>> 339 AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \
>> 340 ARCH_WANT_FRAME_POINTERS
537 default y if (DEBUG_INFO && UML) || AR 341 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
538 help 342 help
539 If you say Y here the resulting kern 343 If you say Y here the resulting kernel image will be slightly
540 larger and slower, but it gives very 344 larger and slower, but it gives very useful debugging information
541 in case of kernel bugs. (precise oop 345 in case of kernel bugs. (precise oopses/stacktraces/warnings)
542 346
543 config OBJTOOL <<
544 bool <<
545 <<
546 config STACK_VALIDATION 347 config STACK_VALIDATION
547 bool "Compile-time stack metadata vali 348 bool "Compile-time stack metadata validation"
548 depends on HAVE_STACK_VALIDATION && UN !! 349 depends on HAVE_STACK_VALIDATION
549 select OBJTOOL <<
550 default n 350 default n
551 help 351 help
552 Validate frame pointer rules at comp !! 352 Add compile-time checks to validate stack metadata, including frame
553 runtime stack traces are more reliab !! 353 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
>> 354 that runtime stack traces are more reliable.
554 355
555 For more information, see 356 For more information, see
556 tools/objtool/Documentation/objtool. !! 357 tools/objtool/Documentation/stack-validation.txt.
557 <<
558 config NOINSTR_VALIDATION <<
559 bool <<
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 <<
573 358
574 config DEBUG_FORCE_WEAK_PER_CPU 359 config DEBUG_FORCE_WEAK_PER_CPU
575 bool "Force weak per-cpu definitions" 360 bool "Force weak per-cpu definitions"
576 depends on DEBUG_KERNEL 361 depends on DEBUG_KERNEL
577 help 362 help
578 s390 and alpha require percpu variab 363 s390 and alpha require percpu variables in modules to be
579 defined weak to work around addressi 364 defined weak to work around addressing range issue which
580 puts the following two restrictions 365 puts the following two restrictions on percpu variable
581 definitions. 366 definitions.
582 367
583 1. percpu symbols must be unique whe 368 1. percpu symbols must be unique whether static or not
584 2. percpu variables can't be defined 369 2. percpu variables can't be defined inside a function
585 370
586 To ensure that generic code follows 371 To ensure that generic code follows the above rules, this
587 option forces all percpu variables t 372 option forces all percpu variables to be defined as weak.
588 373
589 endmenu # "Compiler options" 374 endmenu # "Compiler options"
590 375
591 menu "Generic Kernel Debugging Instruments" <<
592 <<
593 config MAGIC_SYSRQ 376 config MAGIC_SYSRQ
594 bool "Magic SysRq key" 377 bool "Magic SysRq key"
595 depends on !UML 378 depends on !UML
596 help 379 help
597 If you say Y here, you will have som 380 If you say Y here, you will have some control over the system even
598 if the system crashes for example du 381 if the system crashes for example during kernel debugging (e.g., you
599 will be able to flush the buffer cac 382 will be able to flush the buffer cache to disk, reboot the system
600 immediately or dump some status info 383 immediately or dump some status information). This is accomplished
601 by pressing various keys while holdi 384 by pressing various keys while holding SysRq (Alt+PrintScreen). It
602 also works on a serial console (on P 385 also works on a serial console (on PC hardware at least), if you
603 send a BREAK and then within 5 secon 386 send a BREAK and then within 5 seconds a command keypress. The
604 keys are documented in <file:Documen !! 387 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
605 Don't say Y unless you really know w !! 388 unless you really know what this hack does.
606 389
607 config MAGIC_SYSRQ_DEFAULT_ENABLE 390 config MAGIC_SYSRQ_DEFAULT_ENABLE
608 hex "Enable magic SysRq key functions 391 hex "Enable magic SysRq key functions by default"
609 depends on MAGIC_SYSRQ 392 depends on MAGIC_SYSRQ
610 default 0x1 393 default 0x1
611 help 394 help
612 Specifies which SysRq key functions 395 Specifies which SysRq key functions are enabled by default.
613 This may be set to 1 or 0 to enable 396 This may be set to 1 or 0 to enable or disable them all, or
614 to a bitmask as described in Documen !! 397 to a bitmask as described in Documentation/sysrq.txt.
615 <<
616 config MAGIC_SYSRQ_SERIAL <<
617 bool "Enable magic SysRq key over seri <<
618 depends on MAGIC_SYSRQ <<
619 default y <<
620 help <<
621 Many embedded boards have a disconne <<
622 generate some garbage that can lead <<
623 This option allows you to decide whe <<
624 magic SysRq key. <<
625 <<
626 config MAGIC_SYSRQ_SERIAL_SEQUENCE <<
627 string "Char sequence that enables mag <<
628 depends on MAGIC_SYSRQ_SERIAL <<
629 default "" <<
630 help <<
631 Specifies a sequence of characters t <<
632 SysRq on a serial console. <<
633 398
634 If unsure, leave an empty string and !! 399 config DEBUG_KERNEL
635 !! 400 bool "Kernel debugging"
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 401 help
674 Access is off. Clients get -PERM whe !! 402 Say Y here if you are developing drivers or trying to debug and
675 debugfs tree and debugfs is not regi !! 403 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" <<
691 404
692 menu "Memory Debugging" 405 menu "Memory Debugging"
693 406
694 source "mm/Kconfig.debug" !! 407 source mm/Kconfig.debug
695 408
696 config DEBUG_OBJECTS 409 config DEBUG_OBJECTS
697 bool "Debug object operations" 410 bool "Debug object operations"
698 depends on DEBUG_KERNEL 411 depends on DEBUG_KERNEL
699 help 412 help
700 If you say Y here, additional code w 413 If you say Y here, additional code will be inserted into the
701 kernel to track the life time of var 414 kernel to track the life time of various objects and validate
702 the operations on those objects. 415 the operations on those objects.
703 416
704 config DEBUG_OBJECTS_SELFTEST 417 config DEBUG_OBJECTS_SELFTEST
705 bool "Debug objects selftest" 418 bool "Debug objects selftest"
706 depends on DEBUG_OBJECTS 419 depends on DEBUG_OBJECTS
707 help 420 help
708 This enables the selftest of the obj 421 This enables the selftest of the object debug code.
709 422
710 config DEBUG_OBJECTS_FREE 423 config DEBUG_OBJECTS_FREE
711 bool "Debug objects in freed memory" 424 bool "Debug objects in freed memory"
712 depends on DEBUG_OBJECTS 425 depends on DEBUG_OBJECTS
713 help 426 help
714 This enables checks whether a k/v fr 427 This enables checks whether a k/v free operation frees an area
715 which contains an object which has n 428 which contains an object which has not been deactivated
716 properly. This can make kmalloc/kfre 429 properly. This can make kmalloc/kfree-intensive workloads
717 much slower. 430 much slower.
718 431
719 config DEBUG_OBJECTS_TIMERS 432 config DEBUG_OBJECTS_TIMERS
720 bool "Debug timer objects" 433 bool "Debug timer objects"
721 depends on DEBUG_OBJECTS 434 depends on DEBUG_OBJECTS
722 help 435 help
723 If you say Y here, additional code w 436 If you say Y here, additional code will be inserted into the
724 timer routines to track the life tim 437 timer routines to track the life time of timer objects and
725 validate the timer operations. 438 validate the timer operations.
726 439
727 config DEBUG_OBJECTS_WORK 440 config DEBUG_OBJECTS_WORK
728 bool "Debug work objects" 441 bool "Debug work objects"
729 depends on DEBUG_OBJECTS 442 depends on DEBUG_OBJECTS
730 help 443 help
731 If you say Y here, additional code w 444 If you say Y here, additional code will be inserted into the
732 work queue routines to track the lif 445 work queue routines to track the life time of work objects and
733 validate the work operations. 446 validate the work operations.
734 447
735 config DEBUG_OBJECTS_RCU_HEAD 448 config DEBUG_OBJECTS_RCU_HEAD
736 bool "Debug RCU callbacks objects" 449 bool "Debug RCU callbacks objects"
737 depends on DEBUG_OBJECTS 450 depends on DEBUG_OBJECTS
738 help 451 help
739 Enable this to turn on debugging of 452 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
740 453
741 config DEBUG_OBJECTS_PERCPU_COUNTER 454 config DEBUG_OBJECTS_PERCPU_COUNTER
742 bool "Debug percpu counter objects" 455 bool "Debug percpu counter objects"
743 depends on DEBUG_OBJECTS 456 depends on DEBUG_OBJECTS
744 help 457 help
745 If you say Y here, additional code w 458 If you say Y here, additional code will be inserted into the
746 percpu counter routines to track the 459 percpu counter routines to track the life time of percpu counter
747 objects and validate the percpu coun 460 objects and validate the percpu counter operations.
748 461
749 config DEBUG_OBJECTS_ENABLE_DEFAULT 462 config DEBUG_OBJECTS_ENABLE_DEFAULT
750 int "debug_objects bootup default valu 463 int "debug_objects bootup default value (0-1)"
751 range 0 1 !! 464 range 0 1
752 default "1" !! 465 default "1"
753 depends on DEBUG_OBJECTS !! 466 depends on DEBUG_OBJECTS
>> 467 help
>> 468 Debug objects boot parameter default value
>> 469
>> 470 config DEBUG_SLAB
>> 471 bool "Debug slab memory allocations"
>> 472 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
>> 473 help
>> 474 Say Y here to have the kernel do limited verification on memory
>> 475 allocation as well as poisoning memory on free to catch use of freed
>> 476 memory. This can make kmalloc/kfree-intensive workloads much slower.
>> 477
>> 478 config DEBUG_SLAB_LEAK
>> 479 bool "Memory leak debugging"
>> 480 depends on DEBUG_SLAB
>> 481
>> 482 config SLUB_DEBUG_ON
>> 483 bool "SLUB debugging on by default"
>> 484 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
>> 485 default n
>> 486 help
>> 487 Boot with debugging on by default. SLUB boots by default with
>> 488 the runtime debug capabilities switched off. Enabling this is
>> 489 equivalent to specifying the "slub_debug" parameter on boot.
>> 490 There is no support for more fine grained debug control like
>> 491 possible with slub_debug=xxx. SLUB debugging may be switched
>> 492 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
>> 493 "slub_debug=-".
>> 494
>> 495 config SLUB_STATS
>> 496 default n
>> 497 bool "Enable SLUB performance statistics"
>> 498 depends on SLUB && SYSFS
>> 499 help
>> 500 SLUB statistics are useful to debug SLUBs allocation behavior in
>> 501 order find ways to optimize the allocator. This should never be
>> 502 enabled for production use since keeping statistics slows down
>> 503 the allocator by a few percentage points. The slabinfo command
>> 504 supports the determination of the most active slabs to figure
>> 505 out which slabs are relevant to a particular load.
>> 506 Try running: slabinfo -DA
>> 507
>> 508 config HAVE_DEBUG_KMEMLEAK
>> 509 bool
>> 510
>> 511 config DEBUG_KMEMLEAK
>> 512 bool "Kernel memory leak detector"
>> 513 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
>> 514 select DEBUG_FS
>> 515 select STACKTRACE if STACKTRACE_SUPPORT
>> 516 select KALLSYMS
>> 517 select CRC32
754 help 518 help
755 Debug objects boot parameter default !! 519 Say Y here if you want to enable the memory leak
>> 520 detector. The memory allocation/freeing is traced in a way
>> 521 similar to the Boehm's conservative garbage collector, the
>> 522 difference being that the orphan objects are not freed but
>> 523 only shown in /sys/kernel/debug/kmemleak. Enabling this
>> 524 feature will introduce an overhead to memory
>> 525 allocations. See Documentation/kmemleak.txt for more
>> 526 details.
756 527
757 config SHRINKER_DEBUG !! 528 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
758 bool "Enable shrinker debugging suppor !! 529 of finding leaks due to the slab objects poisoning.
759 depends on DEBUG_FS !! 530
>> 531 In order to access the kmemleak file, debugfs needs to be
>> 532 mounted (usually at /sys/kernel/debug).
>> 533
>> 534 config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
>> 535 int "Maximum kmemleak early log entries"
>> 536 depends on DEBUG_KMEMLEAK
>> 537 range 200 40000
>> 538 default 16000
760 help 539 help
761 Say Y to enable the shrinker debugfs !! 540 Kmemleak must track all the memory allocations to avoid
762 visibility into the kernel memory sh !! 541 reporting false positives. Since memory may be allocated or
763 Disable it to avoid an extra memory !! 542 freed before kmemleak is initialised, an early log buffer is
>> 543 used to store these actions. If kmemleak reports "early log
>> 544 buffer exceeded", please increase this value.
764 545
765 config DEBUG_STACK_USAGE !! 546 config DEBUG_KMEMLEAK_TEST
766 bool "Stack utilization instrumentatio !! 547 tristate "Simple test for the kernel memory leak detector"
767 depends on DEBUG_KERNEL !! 548 depends on DEBUG_KMEMLEAK && m
768 help 549 help
769 Enables the display of the minimum a !! 550 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 <<
773 551
774 This option will slow down process c !! 552 If unsure, say N.
775 553
776 config SCHED_STACK_END_CHECK !! 554 config DEBUG_KMEMLEAK_DEFAULT_OFF
777 bool "Detect stack corruption on calls !! 555 bool "Default kmemleak to off"
778 depends on DEBUG_KERNEL !! 556 depends on DEBUG_KMEMLEAK
779 default n <<
780 help 557 help
781 This option checks for a stack overr !! 558 Say Y here to disable kmemleak by default. It can then be enabled
782 If the stack end location is found t !! 559 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 <<
787 560
788 config ARCH_HAS_DEBUG_VM_PGTABLE !! 561 config DEBUG_STACK_USAGE
789 bool !! 562 bool "Stack utilization instrumentation"
>> 563 depends on DEBUG_KERNEL && !IA64
790 help 564 help
791 An architecture should select this w !! 565 Enables the display of the minimum amount of free stack which each
792 build and run DEBUG_VM_PGTABLE. !! 566 task has ever had available in the sysrq-T and sysrq-P debug output.
793 567
794 config DEBUG_VM_IRQSOFF !! 568 This option will slow down process creation somewhat.
795 def_bool DEBUG_VM && !PREEMPT_RT <<
796 569
797 config DEBUG_VM 570 config DEBUG_VM
798 bool "Debug VM" 571 bool "Debug VM"
799 depends on DEBUG_KERNEL 572 depends on DEBUG_KERNEL
800 help 573 help
801 Enable this to turn on extended chec 574 Enable this to turn on extended checks in the virtual-memory system
802 that may impact performance. !! 575 that may impact performance.
803 <<
804 If unsure, say N. <<
805 <<
806 config DEBUG_VM_SHOOT_LAZIES <<
807 bool "Debug MMU_LAZY_TLB_SHOOTDOWN imp <<
808 depends on DEBUG_VM <<
809 depends on MMU_LAZY_TLB_SHOOTDOWN <<
810 help <<
811 Enable additional IPIs that ensure l <<
812 before the mm is freed. <<
813 576
814 If unsure, say N. 577 If unsure, say N.
815 578
816 config DEBUG_VM_MAPLE_TREE !! 579 config DEBUG_VM_VMACACHE
817 bool "Debug VM maple trees" !! 580 bool "Debug VMA caching"
818 depends on DEBUG_VM 581 depends on DEBUG_VM
819 select DEBUG_MAPLE_TREE <<
820 help 582 help
821 Enable VM maple tree debugging infor !! 583 Enable this to turn on VMA caching debug information. Doing so
>> 584 can cause significant overhead, so only enable it in non-production
>> 585 environments.
822 586
823 If unsure, say N. 587 If unsure, say N.
824 588
825 config DEBUG_VM_RB 589 config DEBUG_VM_RB
826 bool "Debug VM red-black trees" 590 bool "Debug VM red-black trees"
827 depends on DEBUG_VM 591 depends on DEBUG_VM
828 help 592 help
829 Enable VM red-black tree debugging i 593 Enable VM red-black tree debugging information and extra validations.
830 594
831 If unsure, say N. 595 If unsure, say N.
832 596
833 config DEBUG_VM_PGFLAGS 597 config DEBUG_VM_PGFLAGS
834 bool "Debug page-flags operations" 598 bool "Debug page-flags operations"
835 depends on DEBUG_VM 599 depends on DEBUG_VM
836 help 600 help
837 Enables extra validation on page fla 601 Enables extra validation on page flags operations.
838 602
839 If unsure, say N. 603 If unsure, say N.
840 604
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 <<
858 bool <<
859 <<
860 config DEBUG_VIRTUAL 605 config DEBUG_VIRTUAL
861 bool "Debug VM translations" 606 bool "Debug VM translations"
862 depends on DEBUG_KERNEL && ARCH_HAS_DE !! 607 depends on DEBUG_KERNEL && X86
863 help 608 help
864 Enable some costly sanity checks in 609 Enable some costly sanity checks in virtual to page code. This can
865 catch mistakes with virt_to_page() a 610 catch mistakes with virt_to_page() and friends.
866 611
867 If unsure, say N. 612 If unsure, say N.
868 613
869 config DEBUG_NOMMU_REGIONS 614 config DEBUG_NOMMU_REGIONS
870 bool "Debug the global anon/private NO 615 bool "Debug the global anon/private NOMMU mapping region tree"
871 depends on DEBUG_KERNEL && !MMU 616 depends on DEBUG_KERNEL && !MMU
872 help 617 help
873 This option causes the global tree o 618 This option causes the global tree of anonymous and private mapping
874 regions to be regularly checked for 619 regions to be regularly checked for invalid topology.
875 620
876 config DEBUG_MEMORY_INIT 621 config DEBUG_MEMORY_INIT
877 bool "Debug memory initialisation" if 622 bool "Debug memory initialisation" if EXPERT
878 default !EXPERT 623 default !EXPERT
879 help 624 help
880 Enable this for additional checks du 625 Enable this for additional checks during memory initialisation.
881 The sanity checks verify aspects of 626 The sanity checks verify aspects of the VM such as the memory model
882 and other information provided by th 627 and other information provided by the architecture. Verbose
883 information will be printed at KERN_ 628 information will be printed at KERN_DEBUG loglevel depending
884 on the mminit_loglevel= command-line 629 on the mminit_loglevel= command-line option.
885 630
886 If unsure, say Y 631 If unsure, say Y
887 632
888 config MEMORY_NOTIFIER_ERROR_INJECT 633 config MEMORY_NOTIFIER_ERROR_INJECT
889 tristate "Memory hotplug notifier erro 634 tristate "Memory hotplug notifier error injection module"
890 depends on MEMORY_HOTPLUG && NOTIFIER_ !! 635 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
891 help 636 help
892 This option provides the ability to 637 This option provides the ability to inject artificial errors to
893 memory hotplug notifier chain callba 638 memory hotplug notifier chain callbacks. It is controlled through
894 debugfs interface under /sys/kernel/ 639 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
895 640
896 If the notifier call chain should be 641 If the notifier call chain should be failed with some events
897 notified, write the error code to "a 642 notified, write the error code to "actions/<notifier event>/error".
898 643
899 Example: Inject memory hotplug offli 644 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
900 645
901 # cd /sys/kernel/debug/notifier-erro 646 # cd /sys/kernel/debug/notifier-error-inject/memory
902 # echo -12 > actions/MEM_GOING_OFFLI 647 # echo -12 > actions/MEM_GOING_OFFLINE/error
903 # echo offline > /sys/devices/system 648 # echo offline > /sys/devices/system/memory/memoryXXX/state
904 bash: echo: write error: Cannot allo 649 bash: echo: write error: Cannot allocate memory
905 650
906 To compile this code as a module, ch 651 To compile this code as a module, choose M here: the module will
907 be called memory-notifier-error-inje 652 be called memory-notifier-error-inject.
908 653
909 If unsure, say N. 654 If unsure, say N.
910 655
911 config DEBUG_PER_CPU_MAPS 656 config DEBUG_PER_CPU_MAPS
912 bool "Debug access to per_cpu maps" 657 bool "Debug access to per_cpu maps"
913 depends on DEBUG_KERNEL 658 depends on DEBUG_KERNEL
914 depends on SMP 659 depends on SMP
915 help 660 help
916 Say Y to verify that the per_cpu map 661 Say Y to verify that the per_cpu map being accessed has
917 been set up. This adds a fair amount 662 been set up. This adds a fair amount of code to kernel memory
918 and decreases performance. 663 and decreases performance.
919 664
920 Say N if unsure. 665 Say N if unsure.
921 666
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 667 config DEBUG_HIGHMEM
943 bool "Highmem debugging" 668 bool "Highmem debugging"
944 depends on DEBUG_KERNEL && HIGHMEM 669 depends on DEBUG_KERNEL && HIGHMEM
945 select DEBUG_KMAP_LOCAL_FORCE_MAP if A <<
946 select DEBUG_KMAP_LOCAL <<
947 help 670 help
948 This option enables additional error 671 This option enables additional error checking for high memory
949 systems. Disable for production sys 672 systems. Disable for production systems.
950 673
951 config HAVE_DEBUG_STACKOVERFLOW 674 config HAVE_DEBUG_STACKOVERFLOW
952 bool 675 bool
953 676
954 config DEBUG_STACKOVERFLOW 677 config DEBUG_STACKOVERFLOW
955 bool "Check for stack overflows" 678 bool "Check for stack overflows"
956 depends on DEBUG_KERNEL && HAVE_DEBUG_ 679 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
957 help !! 680 ---help---
958 Say Y here if you want to check for 681 Say Y here if you want to check for overflows of kernel, IRQ
959 and exception stacks (if your archit 682 and exception stacks (if your architecture uses them). This
960 option will show detailed messages i 683 option will show detailed messages if free stack space drops
961 below a certain limit. 684 below a certain limit.
962 685
963 These kinds of bugs usually occur wh 686 These kinds of bugs usually occur when call-chains in the
964 kernel get too deep, especially when 687 kernel get too deep, especially when interrupts are
965 involved. 688 involved.
966 689
967 Use this in cases where you see appa 690 Use this in cases where you see apparently random memory
968 corruption, especially if it appears 691 corruption, especially if it appears in 'struct thread_info'
969 692
970 If in doubt, say "N". 693 If in doubt, say "N".
971 694
972 config CODE_TAGGING !! 695 source "lib/Kconfig.kmemcheck"
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 696
1003 source "lib/Kconfig.kasan" 697 source "lib/Kconfig.kasan"
1004 source "lib/Kconfig.kfence" <<
1005 source "lib/Kconfig.kmsan" <<
1006 698
1007 endmenu # "Memory Debugging" 699 endmenu # "Memory Debugging"
1008 700
1009 config DEBUG_SHIRQ !! 701 config ARCH_HAS_KCOV
1010 bool "Debug shared IRQ handlers" !! 702 bool
1011 depends on DEBUG_KERNEL <<
1012 help 703 help
1013 Enable this to generate a spurious !! 704 KCOV does not have any arch-specific code, but currently it is enabled
1014 interrupt handler is deregistered ( !! 705 only for x86_64. KCOV requires testing on other archs, and most likely
1015 is currently disabled). Drivers nee !! 706 disabling of instrumentation for some early boot code.
1016 don't and need to be caught. <<
1017 707
1018 menu "Debug Oops, Lockups and Hangs" !! 708 config KCOV
1019 !! 709 bool "Code coverage for fuzzing"
1020 config PANIC_ON_OOPS !! 710 depends on ARCH_HAS_KCOV
1021 bool "Panic on Oops" !! 711 select DEBUG_FS
>> 712 select GCC_PLUGINS if !COMPILE_TEST
>> 713 select GCC_PLUGIN_SANCOV if !COMPILE_TEST
1022 help 714 help
1023 Say Y here to enable the kernel to !! 715 KCOV exposes kernel code coverage information in a form suitable
1024 has the same effect as setting oops !! 716 for coverage-guided fuzzing (randomized testing).
1025 line. <<
1026 717
1027 This feature is useful to ensure th !! 718 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1028 anything erroneous after an oops wh !! 719 different machines and across reboots. If you need stable PC values,
1029 corruption or other issues. !! 720 disable RANDOMIZE_BASE.
1030 721
1031 Say N if unsure. !! 722 For more details, see Documentation/kcov.txt.
1032 723
1033 config PANIC_ON_OOPS_VALUE !! 724 config KCOV_INSTRUMENT_ALL
1034 int !! 725 bool "Instrument all code by default"
1035 range 0 1 !! 726 depends on KCOV
1036 default 0 if !PANIC_ON_OOPS !! 727 default y if KCOV
1037 default 1 if PANIC_ON_OOPS !! 728 help
>> 729 If you are doing generic system call fuzzing (like e.g. syzkaller),
>> 730 then you will want to instrument the whole kernel and you should
>> 731 say y here. If you are doing more targeted fuzzing (like e.g.
>> 732 filesystem fuzzing with AFL) then you will want to enable coverage
>> 733 for more specific subsets of files, and should say n here.
1038 734
1039 config PANIC_TIMEOUT !! 735 config DEBUG_SHIRQ
1040 int "panic timeout" !! 736 bool "Debug shared IRQ handlers"
1041 default 0 !! 737 depends on DEBUG_KERNEL
1042 help 738 help
1043 Set the timeout value (in seconds) !! 739 Enable this to generate a spurious interrupt as soon as a shared
1044 the kernel panics. If n = 0, then w !! 740 interrupt handler is registered, and just before one is deregistered.
1045 value n > 0 will wait n seconds bef !! 741 Drivers ought to be able to handle interrupts coming in at those
1046 value n < 0 will reboot immediately !! 742 points; some don't and need to be caught.
1047 with the kernel command line option <<
1048 /proc/sys/kernel/panic. <<
1049 743
1050 config LOCKUP_DETECTOR !! 744 menu "Debug Lockups and Hangs"
1051 bool <<
1052 745
1053 config SOFTLOCKUP_DETECTOR !! 746 config LOCKUP_DETECTOR
1054 bool "Detect Soft Lockups" !! 747 bool "Detect Hard and Soft Lockups"
1055 depends on DEBUG_KERNEL && !S390 748 depends on DEBUG_KERNEL && !S390
1056 select LOCKUP_DETECTOR <<
1057 help 749 help
1058 Say Y here to enable the kernel to 750 Say Y here to enable the kernel to act as a watchdog to detect
1059 soft lockups. !! 751 hard and soft lockups.
1060 752
1061 Softlockups are bugs that cause the 753 Softlockups are bugs that cause the kernel to loop in kernel
1062 mode for more than 20 seconds, with 754 mode for more than 20 seconds, without giving other tasks a
1063 chance to run. The current stack t 755 chance to run. The current stack trace is displayed upon
1064 detection and the system will stay 756 detection and the system will stay locked up.
1065 757
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 <<
1081 bool "Panic (Reboot) On Soft Lockups" <<
1082 depends on SOFTLOCKUP_DETECTOR <<
1083 help <<
1084 Say Y here to enable the kernel to <<
1085 which are bugs that cause the kerne <<
1086 mode for more than 20 seconds (conf <<
1087 sysctl), without giving other tasks <<
1088 <<
1089 The panic can be used in combinatio <<
1090 to cause the system to reboot autom <<
1091 lockup has been detected. This feat <<
1092 high-availability systems that have <<
1093 where a lockup must be resolved ASA <<
1094 <<
1095 Say N if unsure. <<
1096 <<
1097 config HAVE_HARDLOCKUP_DETECTOR_BUDDY <<
1098 bool <<
1099 depends on SMP <<
1100 default y <<
1101 <<
1102 # <<
1103 # Global switch whether to build a hardlockup <<
1104 # only when the architecture supports at leas <<
1105 # two exceptions. The hardlockup detector is <<
1106 # <<
1107 # s390: it reported many false positive <<
1108 # <<
1109 # sparc64: has a custom implementation <<
1110 # hardlockup command line optio <<
1111 # <<
1112 config HARDLOCKUP_DETECTOR <<
1113 bool "Detect Hard Lockups" <<
1114 depends on DEBUG_KERNEL && !S390 && ! <<
1115 depends on HAVE_HARDLOCKUP_DETECTOR_P <<
1116 imply HARDLOCKUP_DETECTOR_PERF <<
1117 imply HARDLOCKUP_DETECTOR_BUDDY <<
1118 imply HARDLOCKUP_DETECTOR_ARCH <<
1119 select LOCKUP_DETECTOR <<
1120 <<
1121 help <<
1122 Say Y here to enable the kernel to <<
1123 hard lockups. <<
1124 <<
1125 Hardlockups are bugs that cause the 758 Hardlockups are bugs that cause the CPU to loop in kernel mode
1126 for more than 10 seconds, without l 759 for more than 10 seconds, without letting other interrupts have a
1127 chance to run. The current stack t 760 chance to run. The current stack trace is displayed upon detection
1128 and the system will stay locked up. 761 and the system will stay locked up.
1129 762
1130 # !! 763 The overhead should be minimal. A periodic hrtimer runs to
1131 # Note that arch-specific variants are always !! 764 generate interrupts and kick the watchdog task every 4 seconds.
1132 # !! 765 An NMI is generated every 10 seconds or so to check for hardlockups.
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 766
1172 # !! 767 The frequency of hrtimer and NMI events and the soft and hard lockup
1173 # Both the "perf" and "buddy" hardlockup dete !! 768 thresholds can be controlled through the sysctl watchdog_thresh.
1174 # interrupts. This config enables functions m <<
1175 # <<
1176 config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER <<
1177 bool <<
1178 select SOFTLOCKUP_DETECTOR <<
1179 769
1180 # !! 770 config HARDLOCKUP_DETECTOR
1181 # Enables a timestamp based low pass filter t !! 771 def_bool y
1182 # hard lockup detection which runs too fast d !! 772 depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG
1183 # !! 773 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
1184 config HARDLOCKUP_CHECK_TIMESTAMP <<
1185 bool <<
1186 774
1187 config BOOTPARAM_HARDLOCKUP_PANIC 775 config BOOTPARAM_HARDLOCKUP_PANIC
1188 bool "Panic (Reboot) On Hard Lockups" 776 bool "Panic (Reboot) On Hard Lockups"
1189 depends on HARDLOCKUP_DETECTOR 777 depends on HARDLOCKUP_DETECTOR
1190 help 778 help
1191 Say Y here to enable the kernel to 779 Say Y here to enable the kernel to panic on "hard lockups",
1192 which are bugs that cause the kerne 780 which are bugs that cause the kernel to loop in kernel
1193 mode with interrupts disabled for m 781 mode with interrupts disabled for more than 10 seconds (configurable
1194 using the watchdog_thresh sysctl). 782 using the watchdog_thresh sysctl).
1195 783
1196 Say N if unsure. 784 Say N if unsure.
1197 785
>> 786 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
>> 787 int
>> 788 depends on HARDLOCKUP_DETECTOR
>> 789 range 0 1
>> 790 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
>> 791 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
>> 792
>> 793 config BOOTPARAM_SOFTLOCKUP_PANIC
>> 794 bool "Panic (Reboot) On Soft Lockups"
>> 795 depends on LOCKUP_DETECTOR
>> 796 help
>> 797 Say Y here to enable the kernel to panic on "soft lockups",
>> 798 which are bugs that cause the kernel to loop in kernel
>> 799 mode for more than 20 seconds (configurable using the watchdog_thresh
>> 800 sysctl), without giving other tasks a chance to run.
>> 801
>> 802 The panic can be used in combination with panic_timeout,
>> 803 to cause the system to reboot automatically after a
>> 804 lockup has been detected. This feature is useful for
>> 805 high-availability systems that have uptime guarantees and
>> 806 where a lockup must be resolved ASAP.
>> 807
>> 808 Say N if unsure.
>> 809
>> 810 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
>> 811 int
>> 812 depends on LOCKUP_DETECTOR
>> 813 range 0 1
>> 814 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
>> 815 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
>> 816
1198 config DETECT_HUNG_TASK 817 config DETECT_HUNG_TASK
1199 bool "Detect Hung Tasks" 818 bool "Detect Hung Tasks"
1200 depends on DEBUG_KERNEL 819 depends on DEBUG_KERNEL
1201 default SOFTLOCKUP_DETECTOR !! 820 default LOCKUP_DETECTOR
1202 help 821 help
1203 Say Y here to enable the kernel to 822 Say Y here to enable the kernel to detect "hung tasks",
1204 which are bugs that cause the task 823 which are bugs that cause the task to be stuck in
1205 uninterruptible "D" state indefinit 824 uninterruptible "D" state indefinitely.
1206 825
1207 When a hung task is detected, the k 826 When a hung task is detected, the kernel will print the
1208 current stack trace (which you shou 827 current stack trace (which you should report), but the
1209 task will stay in uninterruptible s 828 task will stay in uninterruptible state. If lockdep is
1210 enabled then all held locks will al 829 enabled then all held locks will also be reported. This
1211 feature has negligible overhead. 830 feature has negligible overhead.
1212 831
1213 config DEFAULT_HUNG_TASK_TIMEOUT 832 config DEFAULT_HUNG_TASK_TIMEOUT
1214 int "Default timeout for hung task de 833 int "Default timeout for hung task detection (in seconds)"
1215 depends on DETECT_HUNG_TASK 834 depends on DETECT_HUNG_TASK
1216 default 120 835 default 120
1217 help 836 help
1218 This option controls the default ti 837 This option controls the default timeout (in seconds) used
1219 to determine when a task has become 838 to determine when a task has become non-responsive and should
1220 be considered hung. 839 be considered hung.
1221 840
1222 It can be adjusted at runtime via t 841 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1223 sysctl or by writing a value to 842 sysctl or by writing a value to
1224 /proc/sys/kernel/hung_task_timeout_ 843 /proc/sys/kernel/hung_task_timeout_secs.
1225 844
1226 A timeout of 0 disables the check. 845 A timeout of 0 disables the check. The default is two minutes.
1227 Keeping the default should be fine 846 Keeping the default should be fine in most cases.
1228 847
1229 config BOOTPARAM_HUNG_TASK_PANIC 848 config BOOTPARAM_HUNG_TASK_PANIC
1230 bool "Panic (Reboot) On Hung Tasks" 849 bool "Panic (Reboot) On Hung Tasks"
1231 depends on DETECT_HUNG_TASK 850 depends on DETECT_HUNG_TASK
1232 help 851 help
1233 Say Y here to enable the kernel to 852 Say Y here to enable the kernel to panic on "hung tasks",
1234 which are bugs that cause the kerne 853 which are bugs that cause the kernel to leave a task stuck
1235 in uninterruptible "D" state. 854 in uninterruptible "D" state.
1236 855
1237 The panic can be used in combinatio 856 The panic can be used in combination with panic_timeout,
1238 to cause the system to reboot autom 857 to cause the system to reboot automatically after a
1239 hung task has been detected. This f 858 hung task has been detected. This feature is useful for
1240 high-availability systems that have 859 high-availability systems that have uptime guarantees and
1241 where a hung tasks must be resolved 860 where a hung tasks must be resolved ASAP.
1242 861
1243 Say N if unsure. 862 Say N if unsure.
1244 863
>> 864 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
>> 865 int
>> 866 depends on DETECT_HUNG_TASK
>> 867 range 0 1
>> 868 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
>> 869 default 1 if BOOTPARAM_HUNG_TASK_PANIC
>> 870
1245 config WQ_WATCHDOG 871 config WQ_WATCHDOG
1246 bool "Detect Workqueue Stalls" 872 bool "Detect Workqueue Stalls"
1247 depends on DEBUG_KERNEL 873 depends on DEBUG_KERNEL
1248 help 874 help
1249 Say Y here to enable stall detectio 875 Say Y here to enable stall detection on workqueues. If a
1250 worker pool doesn't make forward pr 876 worker pool doesn't make forward progress on a pending work
1251 item for over a given amount of tim 877 item for over a given amount of time, 30s by default, a
1252 warning message is printed along wi 878 warning message is printed along with dump of workqueue
1253 state. This can be configured thro 879 state. This can be configured through kernel parameter
1254 "workqueue.watchdog_thresh" and its 880 "workqueue.watchdog_thresh" and its sysfs counterpart.
1255 881
1256 config WQ_CPU_INTENSIVE_REPORT !! 882 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 883
1269 config TEST_LOCKUP !! 884 config PANIC_ON_OOPS
1270 tristate "Test module to generate loc !! 885 bool "Panic on Oops"
1271 depends on m <<
1272 help 886 help
1273 This builds the "test_lockup" modul !! 887 Say Y here to enable the kernel to panic when it oopses. This
1274 that watchdogs and lockup detectors !! 888 has the same effect as setting oops=panic on the kernel command
>> 889 line.
1275 890
1276 Depending on module parameters it c !! 891 This feature is useful to ensure that the kernel does not do
1277 lockup, "hung task", or locking arb !! 892 anything erroneous after an oops which could result in data
1278 Also it could generate series of lo !! 893 corruption or other issues.
1279 894
1280 If unsure, say N. !! 895 Say N if unsure.
1281 896
1282 endmenu # "Debug lockups and hangs" !! 897 config PANIC_ON_OOPS_VALUE
>> 898 int
>> 899 range 0 1
>> 900 default 0 if !PANIC_ON_OOPS
>> 901 default 1 if PANIC_ON_OOPS
1283 902
1284 menu "Scheduler Debugging" !! 903 config PANIC_TIMEOUT
>> 904 int "panic timeout"
>> 905 default 0
>> 906 help
>> 907 Set the timeout value (in seconds) until a reboot occurs when the
>> 908 the kernel panics. If n = 0, then we wait forever. A timeout
>> 909 value n > 0 will wait n seconds before rebooting, while a timeout
>> 910 value n < 0 will reboot immediately.
1285 911
1286 config SCHED_DEBUG 912 config SCHED_DEBUG
1287 bool "Collect scheduler debugging inf 913 bool "Collect scheduler debugging info"
1288 depends on DEBUG_KERNEL && DEBUG_FS !! 914 depends on DEBUG_KERNEL && PROC_FS
1289 default y 915 default y
1290 help 916 help
1291 If you say Y here, the /sys/kernel/ !! 917 If you say Y here, the /proc/sched_debug file will be provided
1292 that can help debug the scheduler. 918 that can help debug the scheduler. The runtime overhead of this
1293 option is minimal. 919 option is minimal.
1294 920
1295 config SCHED_INFO 921 config SCHED_INFO
1296 bool 922 bool
1297 default n 923 default n
1298 924
1299 config SCHEDSTATS 925 config SCHEDSTATS
1300 bool "Collect scheduler statistics" 926 bool "Collect scheduler statistics"
1301 depends on PROC_FS !! 927 depends on DEBUG_KERNEL && PROC_FS
1302 select SCHED_INFO 928 select SCHED_INFO
1303 help 929 help
1304 If you say Y here, additional code 930 If you say Y here, additional code will be inserted into the
1305 scheduler and related routines to c 931 scheduler and related routines to collect statistics about
1306 scheduler behavior and provide them 932 scheduler behavior and provide them in /proc/schedstat. These
1307 stats may be useful for both tuning 933 stats may be useful for both tuning and debugging the scheduler
1308 If you aren't debugging the schedul 934 If you aren't debugging the scheduler or trying to tune a specific
1309 application, you can say N to avoid 935 application, you can say N to avoid the very slight overhead
1310 this adds. 936 this adds.
1311 937
1312 endmenu !! 938 config SCHED_STACK_END_CHECK
>> 939 bool "Detect stack corruption on calls to schedule()"
>> 940 depends on DEBUG_KERNEL
>> 941 default n
>> 942 help
>> 943 This option checks for a stack overrun on calls to schedule().
>> 944 If the stack end location is found to be over written always panic as
>> 945 the content of the corrupted region can no longer be trusted.
>> 946 This is to ensure no erroneous behaviour occurs which could result in
>> 947 data corruption or a sporadic crash at a later stage once the region
>> 948 is examined. The runtime overhead introduced is minimal.
1313 949
1314 config DEBUG_TIMEKEEPING 950 config DEBUG_TIMEKEEPING
1315 bool "Enable extra timekeeping sanity 951 bool "Enable extra timekeeping sanity checking"
1316 help 952 help
1317 This option will enable additional 953 This option will enable additional timekeeping sanity checks
1318 which may be helpful when diagnosin 954 which may be helpful when diagnosing issues where timekeeping
1319 problems are suspected. 955 problems are suspected.
1320 956
1321 This may include checks in the time 957 This may include checks in the timekeeping hotpaths, so this
1322 option may have a (very small) perf 958 option may have a (very small) performance impact to some
1323 workloads. 959 workloads.
1324 960
1325 If unsure, say N. 961 If unsure, say N.
1326 962
>> 963 config TIMER_STATS
>> 964 bool "Collect kernel timers statistics"
>> 965 depends on DEBUG_KERNEL && PROC_FS
>> 966 help
>> 967 If you say Y here, additional code will be inserted into the
>> 968 timer routines to collect statistics about kernel timers being
>> 969 reprogrammed. The statistics can be read from /proc/timer_stats.
>> 970 The statistics collection is started by writing 1 to /proc/timer_stats,
>> 971 writing 0 stops it. This feature is useful to collect information
>> 972 about timer usage patterns in kernel and userspace. This feature
>> 973 is lightweight if enabled in the kernel config but not activated
>> 974 (it defaults to deactivated on bootup and will only be activated
>> 975 if some application like powertop activates it explicitly).
>> 976
1327 config DEBUG_PREEMPT 977 config DEBUG_PREEMPT
1328 bool "Debug preemptible kernel" 978 bool "Debug preemptible kernel"
1329 depends on DEBUG_KERNEL && PREEMPTION !! 979 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
>> 980 default y
1330 help 981 help
1331 If you say Y here then the kernel w 982 If you say Y here then the kernel will use a debug variant of the
1332 commonly used smp_processor_id() fu 983 commonly used smp_processor_id() function and will print warnings
1333 if kernel code uses it in a preempt 984 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1334 will detect preemption count underf 985 will detect preemption count underflows.
1335 986
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 987 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1341 988
1342 config LOCK_DEBUGGING_SUPPORT !! 989 config DEBUG_RT_MUTEXES
1343 bool !! 990 bool "RT Mutex debugging, deadlock detection"
1344 depends on TRACE_IRQFLAGS_SUPPORT && !! 991 depends on DEBUG_KERNEL && RT_MUTEXES
1345 default y !! 992 help
>> 993 This allows rt mutex semantics violations and rt mutex related
>> 994 deadlocks (lockups) to be detected and reported automatically.
>> 995
>> 996 config DEBUG_SPINLOCK
>> 997 bool "Spinlock and rw-lock debugging: basic checks"
>> 998 depends on DEBUG_KERNEL
>> 999 select UNINLINE_SPIN_UNLOCK
>> 1000 help
>> 1001 Say Y here and build SMP to catch missing spinlock initialization
>> 1002 and certain other kinds of spinlock errors commonly made. This is
>> 1003 best used in conjunction with the NMI watchdog so that spinlock
>> 1004 deadlocks are also debuggable.
>> 1005
>> 1006 config DEBUG_MUTEXES
>> 1007 bool "Mutex debugging: basic checks"
>> 1008 depends on DEBUG_KERNEL
>> 1009 help
>> 1010 This feature allows mutex semantics violations to be detected and
>> 1011 reported.
>> 1012
>> 1013 config DEBUG_WW_MUTEX_SLOWPATH
>> 1014 bool "Wait/wound mutex debugging: Slowpath testing"
>> 1015 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
>> 1016 select DEBUG_LOCK_ALLOC
>> 1017 select DEBUG_SPINLOCK
>> 1018 select DEBUG_MUTEXES
>> 1019 help
>> 1020 This feature enables slowpath testing for w/w mutex users by
>> 1021 injecting additional -EDEADLK wound/backoff cases. Together with
>> 1022 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
>> 1023 will test all possible w/w mutex interface abuse with the
>> 1024 exception of simply not acquiring all the required locks.
>> 1025 Note that this feature can introduce significant overhead, so
>> 1026 it really should not be enabled in a production or distro kernel,
>> 1027 even a debug kernel. If you are a driver writer, enable it. If
>> 1028 you are a distro, do not.
>> 1029
>> 1030 config DEBUG_LOCK_ALLOC
>> 1031 bool "Lock debugging: detect incorrect freeing of live locks"
>> 1032 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
>> 1033 select DEBUG_SPINLOCK
>> 1034 select DEBUG_MUTEXES
>> 1035 select LOCKDEP
>> 1036 help
>> 1037 This feature will check whether any held lock (spinlock, rwlock,
>> 1038 mutex or rwsem) is incorrectly freed by the kernel, via any of the
>> 1039 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
>> 1040 vfree(), etc.), whether a live lock is incorrectly reinitialized via
>> 1041 spin_lock_init()/mutex_init()/etc., or whether there is any lock
>> 1042 held during task exit.
1346 1043
1347 config PROVE_LOCKING 1044 config PROVE_LOCKING
1348 bool "Lock debugging: prove locking c 1045 bool "Lock debugging: prove locking correctness"
1349 depends on DEBUG_KERNEL && LOCK_DEBUG !! 1046 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1350 select LOCKDEP 1047 select LOCKDEP
1351 select DEBUG_SPINLOCK 1048 select DEBUG_SPINLOCK
1352 select DEBUG_MUTEXES if !PREEMPT_RT !! 1049 select DEBUG_MUTEXES
1353 select DEBUG_RT_MUTEXES if RT_MUTEXES <<
1354 select DEBUG_RWSEMS if !PREEMPT_RT <<
1355 select DEBUG_WW_MUTEX_SLOWPATH <<
1356 select DEBUG_LOCK_ALLOC 1050 select DEBUG_LOCK_ALLOC
1357 select PREEMPT_COUNT if !ARCH_NO_PREE <<
1358 select TRACE_IRQFLAGS 1051 select TRACE_IRQFLAGS
1359 default n 1052 default n
1360 help 1053 help
1361 This feature enables the kernel to p 1054 This feature enables the kernel to prove that all locking
1362 that occurs in the kernel runtime is 1055 that occurs in the kernel runtime is mathematically
1363 correct: that under no circumstance 1056 correct: that under no circumstance could an arbitrary (and
1364 not yet triggered) combination of ob 1057 not yet triggered) combination of observed locking
1365 sequences (on an arbitrary number of 1058 sequences (on an arbitrary number of CPUs, running an
1366 arbitrary number of tasks and interr 1059 arbitrary number of tasks and interrupt contexts) cause a
1367 deadlock. 1060 deadlock.
1368 1061
1369 In short, this feature enables the k 1062 In short, this feature enables the kernel to report locking
1370 related deadlocks before they actual 1063 related deadlocks before they actually occur.
1371 1064
1372 The proof does not depend on how har 1065 The proof does not depend on how hard and complex a
1373 deadlock scenario would be to trigge 1066 deadlock scenario would be to trigger: how many
1374 participant CPUs, tasks and irq-cont 1067 participant CPUs, tasks and irq-contexts would be needed
1375 for it to trigger. The proof also do 1068 for it to trigger. The proof also does not depend on
1376 timing: if a race and a resulting de 1069 timing: if a race and a resulting deadlock is possible
1377 theoretically (no matter how unlikel 1070 theoretically (no matter how unlikely the race scenario
1378 is), it will be proven so and will i 1071 is), it will be proven so and will immediately be
1379 reported by the kernel (once the eve 1072 reported by the kernel (once the event is observed that
1380 makes the deadlock theoretically pos 1073 makes the deadlock theoretically possible).
1381 1074
1382 If a deadlock is impossible (i.e. th 1075 If a deadlock is impossible (i.e. the locking rules, as
1383 observed by the kernel, are mathemat 1076 observed by the kernel, are mathematically correct), the
1384 kernel reports nothing. 1077 kernel reports nothing.
1385 1078
1386 NOTE: this feature can also be enabl 1079 NOTE: this feature can also be enabled for rwlocks, mutexes
1387 and rwsems - in which case all depen 1080 and rwsems - in which case all dependencies between these
1388 different locking variants are obser 1081 different locking variants are observed and mapped too, and
1389 the proof of observed correctness is 1082 the proof of observed correctness is also maintained for an
1390 arbitrary combination of these separ 1083 arbitrary combination of these separate locking variants.
1391 1084
1392 For more details, see Documentation/ !! 1085 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 1086
1403 NOTE: There are known nesting proble !! 1087 config PROVE_LOCKING_SMALL
1404 option expect lockdep splats until t !! 1088 bool
1405 addressed which is work in progress. <<
1406 identify and analyze these problems. <<
1407 check permanently enabled once the m <<
1408 1089
1409 If unsure, select N. !! 1090 config LOCKDEP
>> 1091 bool
>> 1092 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
>> 1093 select STACKTRACE
>> 1094 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !SCORE
>> 1095 select KALLSYMS
>> 1096 select KALLSYMS_ALL
1410 1097
1411 config LOCK_STAT 1098 config LOCK_STAT
1412 bool "Lock usage statistics" 1099 bool "Lock usage statistics"
1413 depends on DEBUG_KERNEL && LOCK_DEBUG !! 1100 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1414 select LOCKDEP 1101 select LOCKDEP
1415 select DEBUG_SPINLOCK 1102 select DEBUG_SPINLOCK
1416 select DEBUG_MUTEXES if !PREEMPT_RT !! 1103 select DEBUG_MUTEXES
1417 select DEBUG_RT_MUTEXES if RT_MUTEXES <<
1418 select DEBUG_LOCK_ALLOC 1104 select DEBUG_LOCK_ALLOC
1419 default n 1105 default n
1420 help 1106 help
1421 This feature enables tracking lock c 1107 This feature enables tracking lock contention points
1422 1108
1423 For more details, see Documentation/ !! 1109 For more details, see Documentation/locking/lockstat.txt
1424 1110
1425 This also enables lock events requir 1111 This also enables lock events required by "perf lock",
1426 subcommand of perf. 1112 subcommand of perf.
1427 If you want to use "perf lock", you 1113 If you want to use "perf lock", you also need to turn on
1428 CONFIG_EVENT_TRACING. 1114 CONFIG_EVENT_TRACING.
1429 1115
1430 CONFIG_LOCK_STAT defines "contended" 1116 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1431 (CONFIG_LOCKDEP defines "acquire" an 1117 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1432 1118
1433 config DEBUG_RT_MUTEXES <<
1434 bool "RT Mutex debugging, deadlock de <<
1435 depends on DEBUG_KERNEL && RT_MUTEXES <<
1436 help <<
1437 This allows rt mutex semantics viola <<
1438 deadlocks (lockups) to be detected a <<
1439 <<
1440 config DEBUG_SPINLOCK <<
1441 bool "Spinlock and rw-lock debugging: <<
1442 depends on DEBUG_KERNEL <<
1443 select UNINLINE_SPIN_UNLOCK <<
1444 help <<
1445 Say Y here and build SMP to catch m <<
1446 and certain other kinds of spinlock <<
1447 best used in conjunction with the N <<
1448 deadlocks are also debuggable. <<
1449 <<
1450 config DEBUG_MUTEXES <<
1451 bool "Mutex debugging: basic checks" <<
1452 depends on DEBUG_KERNEL && !PREEMPT_R <<
1453 help <<
1454 This feature allows mutex semantics <<
1455 reported. <<
1456 <<
1457 config DEBUG_WW_MUTEX_SLOWPATH <<
1458 bool "Wait/wound mutex debugging: Slo <<
1459 depends on DEBUG_KERNEL && LOCK_DEBUG <<
1460 select DEBUG_LOCK_ALLOC <<
1461 select DEBUG_SPINLOCK <<
1462 select DEBUG_MUTEXES if !PREEMPT_RT <<
1463 select DEBUG_RT_MUTEXES if PREEMPT_RT <<
1464 help <<
1465 This feature enables slowpath testin <<
1466 injecting additional -EDEADLK wound/ <<
1467 the full mutex checks enabled with ( <<
1468 will test all possible w/w mutex int <<
1469 exception of simply not acquiring al <<
1470 Note that this feature can introduce <<
1471 it really should not be enabled in a <<
1472 even a debug kernel. If you are a d <<
1473 you are a distro, do not. <<
1474 <<
1475 config DEBUG_RWSEMS <<
1476 bool "RW Semaphore debugging: basic c <<
1477 depends on DEBUG_KERNEL && !PREEMPT_R <<
1478 help <<
1479 This debugging feature allows misma <<
1480 and unlocks to be detected and repo <<
1481 <<
1482 config DEBUG_LOCK_ALLOC <<
1483 bool "Lock debugging: detect incorrec <<
1484 depends on DEBUG_KERNEL && LOCK_DEBUG <<
1485 select DEBUG_SPINLOCK <<
1486 select DEBUG_MUTEXES if !PREEMPT_RT <<
1487 select DEBUG_RT_MUTEXES if RT_MUTEXES <<
1488 select LOCKDEP <<
1489 help <<
1490 This feature will check whether any <<
1491 mutex or rwsem) is incorrectly freed <<
1492 memory-freeing routines (kfree(), km <<
1493 vfree(), etc.), whether a live lock <<
1494 spin_lock_init()/mutex_init()/etc., <<
1495 held during task exit. <<
1496 <<
1497 config LOCKDEP <<
1498 bool <<
1499 depends on DEBUG_KERNEL && LOCK_DEBUG <<
1500 select STACKTRACE <<
1501 select KALLSYMS <<
1502 select KALLSYMS_ALL <<
1503 <<
1504 config LOCKDEP_SMALL <<
1505 bool <<
1506 <<
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 1119 config DEBUG_LOCKDEP
1548 bool "Lock dependency engine debuggin 1120 bool "Lock dependency engine debugging"
1549 depends on DEBUG_KERNEL && LOCKDEP 1121 depends on DEBUG_KERNEL && LOCKDEP
1550 select DEBUG_IRQFLAGS <<
1551 help 1122 help
1552 If you say Y here, the lock depende 1123 If you say Y here, the lock dependency engine will do
1553 additional runtime checks to debug 1124 additional runtime checks to debug itself, at the price
1554 of more runtime overhead. 1125 of more runtime overhead.
1555 1126
1556 config DEBUG_ATOMIC_SLEEP 1127 config DEBUG_ATOMIC_SLEEP
1557 bool "Sleep inside atomic section che 1128 bool "Sleep inside atomic section checking"
1558 select PREEMPT_COUNT 1129 select PREEMPT_COUNT
1559 depends on DEBUG_KERNEL 1130 depends on DEBUG_KERNEL
1560 depends on !ARCH_NO_PREEMPT <<
1561 help 1131 help
1562 If you say Y here, various routines 1132 If you say Y here, various routines which may sleep will become very
1563 noisy if they are called inside ato 1133 noisy if they are called inside atomic sections: when a spinlock is
1564 held, inside an rcu read side criti 1134 held, inside an rcu read side critical section, inside preempt disabled
1565 sections, inside an interrupt, etc. 1135 sections, inside an interrupt, etc...
1566 1136
1567 config DEBUG_LOCKING_API_SELFTESTS 1137 config DEBUG_LOCKING_API_SELFTESTS
1568 bool "Locking API boot-time self-test 1138 bool "Locking API boot-time self-tests"
1569 depends on DEBUG_KERNEL 1139 depends on DEBUG_KERNEL
1570 help 1140 help
1571 Say Y here if you want the kernel t 1141 Say Y here if you want the kernel to run a short self-test during
1572 bootup. The self-test checks whethe 1142 bootup. The self-test checks whether common types of locking bugs
1573 are detected by debugging mechanism 1143 are detected by debugging mechanisms or not. (if you disable
1574 lock debugging then those bugs won' !! 1144 lock debugging then those bugs wont be detected of course.)
1575 The following locking APIs are cove 1145 The following locking APIs are covered: spinlocks, rwlocks,
1576 mutexes and rwsems. 1146 mutexes and rwsems.
1577 1147
1578 config LOCK_TORTURE_TEST 1148 config LOCK_TORTURE_TEST
1579 tristate "torture tests for locking" 1149 tristate "torture tests for locking"
1580 depends on DEBUG_KERNEL 1150 depends on DEBUG_KERNEL
1581 select TORTURE_TEST 1151 select TORTURE_TEST
>> 1152 default n
1582 help 1153 help
1583 This option provides a kernel modul 1154 This option provides a kernel module that runs torture tests
1584 on kernel locking primitives. The 1155 on kernel locking primitives. The kernel module may be built
1585 after the fact on the running kerne 1156 after the fact on the running kernel to be tested, if desired.
1586 1157
1587 Say Y here if you want kernel locki 1158 Say Y here if you want kernel locking-primitive torture tests
1588 to be built into the kernel. 1159 to be built into the kernel.
1589 Say M if you want these torture tes 1160 Say M if you want these torture tests to build as a module.
1590 Say N if you are unsure. 1161 Say N if you are unsure.
1591 1162
1592 config WW_MUTEX_SELFTEST <<
1593 tristate "Wait/wound mutex selftests" <<
1594 help <<
1595 This option provides a kernel modul <<
1596 on the struct ww_mutex locking API. <<
1597 <<
1598 It is recommended to enable DEBUG_W <<
1599 with this test harness. <<
1600 <<
1601 Say M if you want these self tests <<
1602 Say N if you are unsure. <<
1603 <<
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 1163 endmenu # lock debugging
1635 1164
1636 config TRACE_IRQFLAGS 1165 config TRACE_IRQFLAGS
1637 depends on TRACE_IRQFLAGS_SUPPORT <<
1638 bool 1166 bool
1639 help 1167 help
1640 Enables hooks to interrupt enabling 1168 Enables hooks to interrupt enabling and disabling for
1641 either tracing or lock debugging. 1169 either tracing or lock debugging.
1642 1170
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 1171 config STACKTRACE
1667 bool "Stack backtrace support" 1172 bool "Stack backtrace support"
1668 depends on STACKTRACE_SUPPORT 1173 depends on STACKTRACE_SUPPORT
1669 help 1174 help
1670 This option causes the kernel to cr 1175 This option causes the kernel to create a /proc/pid/stack for
1671 every process, showing its current 1176 every process, showing its current stack trace.
1672 It is also used by various kernel d 1177 It is also used by various kernel debugging features that require
1673 stack trace generation. 1178 stack trace generation.
1674 1179
1675 config WARN_ALL_UNSEEDED_RANDOM 1180 config WARN_ALL_UNSEEDED_RANDOM
1676 bool "Warn for all uses of unseeded r 1181 bool "Warn for all uses of unseeded randomness"
1677 default n 1182 default n
1678 help 1183 help
1679 Some parts of the kernel contain bu 1184 Some parts of the kernel contain bugs relating to their use of
1680 cryptographically secure random num 1185 cryptographically secure random numbers before it's actually possible
1681 to generate those numbers securely. 1186 to generate those numbers securely. This setting ensures that these
1682 flaws don't go unnoticed, by enabli 1187 flaws don't go unnoticed, by enabling a message, should this ever
1683 occur. This will allow people with 1188 occur. This will allow people with obscure setups to know when things
1684 are going wrong, so that they might 1189 are going wrong, so that they might contact developers about fixing
1685 it. 1190 it.
1686 1191
1687 Unfortunately, on some models of so 1192 Unfortunately, on some models of some architectures getting
1688 a fully seeded CRNG is extremely di 1193 a fully seeded CRNG is extremely difficult, and so this can
1689 result in dmesg getting spammed for 1194 result in dmesg getting spammed for a surprisingly long
1690 time. This is really bad from a se 1195 time. This is really bad from a security perspective, and
1691 so architecture maintainers really 1196 so architecture maintainers really need to do what they can
1692 to get the CRNG seeded sooner after 1197 to get the CRNG seeded sooner after the system is booted.
1693 However, since users cannot do anyt 1198 However, since users cannot do anything actionable to
1694 address this, by default this optio 1199 address this, by default this option is disabled.
1695 1200
1696 Say Y here if you want to receive w 1201 Say Y here if you want to receive warnings for all uses of
1697 unseeded randomness. This will be 1202 unseeded randomness. This will be of use primarily for
1698 those developers interested in impr !! 1203 those developers interersted in improving the security of
1699 Linux kernels running on their arch 1204 Linux kernels running on their architecture (or
1700 subarchitecture). 1205 subarchitecture).
1701 1206
1702 config DEBUG_KOBJECT 1207 config DEBUG_KOBJECT
1703 bool "kobject debugging" 1208 bool "kobject debugging"
1704 depends on DEBUG_KERNEL 1209 depends on DEBUG_KERNEL
1705 help 1210 help
1706 If you say Y here, some extra kobje 1211 If you say Y here, some extra kobject debugging messages will be sent
1707 to the syslog. !! 1212 to the syslog.
1708 1213
1709 config DEBUG_KOBJECT_RELEASE 1214 config DEBUG_KOBJECT_RELEASE
1710 bool "kobject release debugging" 1215 bool "kobject release debugging"
1711 depends on DEBUG_OBJECTS_TIMERS 1216 depends on DEBUG_OBJECTS_TIMERS
1712 help 1217 help
1713 kobjects are reference counted obje 1218 kobjects are reference counted objects. This means that their
1714 last reference count put is not pre 1219 last reference count put is not predictable, and the kobject can
1715 live on past the point at which a d !! 1220 live on past the point at which a driver decides to drop it's
1716 initial reference to the kobject ga 1221 initial reference to the kobject gained on allocation. An
1717 example of this would be a struct d 1222 example of this would be a struct device which has just been
1718 unregistered. 1223 unregistered.
1719 1224
1720 However, some buggy drivers assume 1225 However, some buggy drivers assume that after such an operation,
1721 the memory backing the kobject can 1226 the memory backing the kobject can be immediately freed. This
1722 goes completely against the princip 1227 goes completely against the principles of a refcounted object.
1723 1228
1724 If you say Y here, the kernel will 1229 If you say Y here, the kernel will delay the release of kobjects
1725 on the last reference count to impr 1230 on the last reference count to improve the visibility of this
1726 kind of kobject release bug. 1231 kind of kobject release bug.
1727 1232
1728 config HAVE_DEBUG_BUGVERBOSE 1233 config HAVE_DEBUG_BUGVERBOSE
1729 bool 1234 bool
1730 1235
1731 menu "Debug kernel data structures" !! 1236 config DEBUG_BUGVERBOSE
>> 1237 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
>> 1238 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
>> 1239 default y
>> 1240 help
>> 1241 Say Y here to make BUG() panics output the file name and line number
>> 1242 of the BUG call as well as the EIP and oops trace. This aids
>> 1243 debugging but costs about 70-100K of memory.
1732 1244
1733 config DEBUG_LIST 1245 config DEBUG_LIST
1734 bool "Debug linked list manipulation" 1246 bool "Debug linked list manipulation"
1735 depends on DEBUG_KERNEL 1247 depends on DEBUG_KERNEL
1736 select LIST_HARDENED <<
1737 help 1248 help
1738 Enable this to turn on extended che !! 1249 Enable this to turn on extended checks in the linked-list
1739 routines. !! 1250 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 1251
1745 If unsure, say N. 1252 If unsure, say N.
1746 1253
1747 config DEBUG_PLIST !! 1254 config DEBUG_PI_LIST
1748 bool "Debug priority linked list mani 1255 bool "Debug priority linked list manipulation"
1749 depends on DEBUG_KERNEL 1256 depends on DEBUG_KERNEL
1750 help 1257 help
1751 Enable this to turn on extended che 1258 Enable this to turn on extended checks in the priority-ordered
1752 linked-list (plist) walking routine 1259 linked-list (plist) walking routines. This checks the entire
1753 list multiple times during each man 1260 list multiple times during each manipulation.
1754 1261
1755 If unsure, say N. 1262 If unsure, say N.
1756 1263
1757 config DEBUG_SG 1264 config DEBUG_SG
1758 bool "Debug SG table operations" 1265 bool "Debug SG table operations"
1759 depends on DEBUG_KERNEL 1266 depends on DEBUG_KERNEL
1760 help 1267 help
1761 Enable this to turn on checks on sc 1268 Enable this to turn on checks on scatter-gather tables. This can
1762 help find problems with drivers tha 1269 help find problems with drivers that do not properly initialize
1763 their sg tables. 1270 their sg tables.
1764 1271
1765 If unsure, say N. 1272 If unsure, say N.
1766 1273
1767 config DEBUG_NOTIFIERS 1274 config DEBUG_NOTIFIERS
1768 bool "Debug notifier call chains" 1275 bool "Debug notifier call chains"
1769 depends on DEBUG_KERNEL 1276 depends on DEBUG_KERNEL
1770 help 1277 help
1771 Enable this to turn on sanity check 1278 Enable this to turn on sanity checking for notifier call chains.
1772 This is most useful for kernel deve 1279 This is most useful for kernel developers to make sure that
1773 modules properly unregister themsel 1280 modules properly unregister themselves from notifier chains.
1774 This is a relatively cheap check bu 1281 This is a relatively cheap check but if you care about maximum
1775 performance, say N. 1282 performance, say N.
1776 1283
1777 config DEBUG_CLOSURES !! 1284 config DEBUG_CREDENTIALS
1778 bool "Debug closures (bcache async wi !! 1285 bool "Debug credential management"
1779 depends on CLOSURES !! 1286 depends on DEBUG_KERNEL
1780 select DEBUG_FS !! 1287 help
>> 1288 Enable this to turn on some debug checking for credential
>> 1289 management. The additional code keeps track of the number of
>> 1290 pointers from task_structs to any given cred struct, and checks to
>> 1291 see that this number never exceeds the usage count of the cred
>> 1292 struct.
>> 1293
>> 1294 Furthermore, if SELinux is enabled, this also checks that the
>> 1295 security pointer in the cred struct is never seen to be invalid.
>> 1296
>> 1297 If unsure, say N.
>> 1298
>> 1299 menu "RCU Debugging"
>> 1300
>> 1301 config PROVE_RCU
>> 1302 def_bool PROVE_LOCKING
>> 1303
>> 1304 config PROVE_RCU_REPEATEDLY
>> 1305 bool "RCU debugging: don't disable PROVE_RCU on first splat"
>> 1306 depends on PROVE_RCU
>> 1307 default n
>> 1308 help
>> 1309 By itself, PROVE_RCU will disable checking upon issuing the
>> 1310 first warning (or "splat"). This feature prevents such
>> 1311 disabling, allowing multiple RCU-lockdep warnings to be printed
>> 1312 on a single reboot.
>> 1313
>> 1314 Say Y to allow multiple RCU-lockdep warnings per boot.
>> 1315
>> 1316 Say N if you are unsure.
>> 1317
>> 1318 config SPARSE_RCU_POINTER
>> 1319 bool "RCU debugging: sparse-based checks for pointer usage"
>> 1320 default n
1781 help 1321 help
1782 Keeps all active closures in a link !! 1322 This feature enables the __rcu sparse annotation for
1783 interface to list them, which makes !! 1323 RCU-protected pointers. This annotation will cause sparse
1784 operations that get stuck. !! 1324 to flag any non-RCU used of annotated pointers. This can be
>> 1325 helpful when debugging RCU usage. Please note that this feature
>> 1326 is not intended to enforce code cleanliness; it is instead merely
>> 1327 a debugging aid.
>> 1328
>> 1329 Say Y to make sparse flag questionable use of RCU-protected pointers
1785 1330
1786 config DEBUG_MAPLE_TREE !! 1331 Say N if you are unsure.
1787 bool "Debug maple trees" !! 1332
>> 1333 config TORTURE_TEST
>> 1334 tristate
>> 1335 default n
>> 1336
>> 1337 config RCU_PERF_TEST
>> 1338 tristate "performance tests for RCU"
1788 depends on DEBUG_KERNEL 1339 depends on DEBUG_KERNEL
>> 1340 select TORTURE_TEST
>> 1341 select SRCU
>> 1342 select TASKS_RCU
>> 1343 default n
1789 help 1344 help
1790 Enable maple tree debugging informa !! 1345 This option provides a kernel module that runs performance
>> 1346 tests on the RCU infrastructure. The kernel module may be built
>> 1347 after the fact on the running kernel to be tested, if desired.
1791 1348
1792 If unsure, say N. !! 1349 Say Y here if you want RCU performance tests to be built into
>> 1350 the kernel.
>> 1351 Say M if you want the RCU performance tests to build as a module.
>> 1352 Say N if you are unsure.
>> 1353
>> 1354 config RCU_TORTURE_TEST
>> 1355 tristate "torture tests for RCU"
>> 1356 depends on DEBUG_KERNEL
>> 1357 select TORTURE_TEST
>> 1358 select SRCU
>> 1359 select TASKS_RCU
>> 1360 default n
>> 1361 help
>> 1362 This option provides a kernel module that runs torture tests
>> 1363 on the RCU infrastructure. The kernel module may be built
>> 1364 after the fact on the running kernel to be tested, if desired.
>> 1365
>> 1366 Say Y here if you want RCU torture tests to be built into
>> 1367 the kernel.
>> 1368 Say M if you want the RCU torture tests to build as a module.
>> 1369 Say N if you are unsure.
1793 1370
1794 endmenu !! 1371 config RCU_TORTURE_TEST_SLOW_PREINIT
>> 1372 bool "Slow down RCU grace-period pre-initialization to expose races"
>> 1373 depends on RCU_TORTURE_TEST
>> 1374 help
>> 1375 This option delays grace-period pre-initialization (the
>> 1376 propagation of CPU-hotplug changes up the rcu_node combining
>> 1377 tree) for a few jiffies between initializing each pair of
>> 1378 consecutive rcu_node structures. This helps to expose races
>> 1379 involving grace-period pre-initialization, in other words, it
>> 1380 makes your kernel less stable. It can also greatly increase
>> 1381 grace-period latency, especially on systems with large numbers
>> 1382 of CPUs. This is useful when torture-testing RCU, but in
>> 1383 almost no other circumstance.
>> 1384
>> 1385 Say Y here if you want your system to crash and hang more often.
>> 1386 Say N if you want a sane system.
>> 1387
>> 1388 config RCU_TORTURE_TEST_SLOW_PREINIT_DELAY
>> 1389 int "How much to slow down RCU grace-period pre-initialization"
>> 1390 range 0 5
>> 1391 default 3
>> 1392 depends on RCU_TORTURE_TEST_SLOW_PREINIT
>> 1393 help
>> 1394 This option specifies the number of jiffies to wait between
>> 1395 each rcu_node structure pre-initialization step.
>> 1396
>> 1397 config RCU_TORTURE_TEST_SLOW_INIT
>> 1398 bool "Slow down RCU grace-period initialization to expose races"
>> 1399 depends on RCU_TORTURE_TEST
>> 1400 help
>> 1401 This option delays grace-period initialization for a few
>> 1402 jiffies between initializing each pair of consecutive
>> 1403 rcu_node structures. This helps to expose races involving
>> 1404 grace-period initialization, in other words, it makes your
>> 1405 kernel less stable. It can also greatly increase grace-period
>> 1406 latency, especially on systems with large numbers of CPUs.
>> 1407 This is useful when torture-testing RCU, but in almost no
>> 1408 other circumstance.
>> 1409
>> 1410 Say Y here if you want your system to crash and hang more often.
>> 1411 Say N if you want a sane system.
>> 1412
>> 1413 config RCU_TORTURE_TEST_SLOW_INIT_DELAY
>> 1414 int "How much to slow down RCU grace-period initialization"
>> 1415 range 0 5
>> 1416 default 3
>> 1417 depends on RCU_TORTURE_TEST_SLOW_INIT
>> 1418 help
>> 1419 This option specifies the number of jiffies to wait between
>> 1420 each rcu_node structure initialization.
>> 1421
>> 1422 config RCU_TORTURE_TEST_SLOW_CLEANUP
>> 1423 bool "Slow down RCU grace-period cleanup to expose races"
>> 1424 depends on RCU_TORTURE_TEST
>> 1425 help
>> 1426 This option delays grace-period cleanup for a few jiffies
>> 1427 between cleaning up each pair of consecutive rcu_node
>> 1428 structures. This helps to expose races involving grace-period
>> 1429 cleanup, in other words, it makes your kernel less stable.
>> 1430 It can also greatly increase grace-period latency, especially
>> 1431 on systems with large numbers of CPUs. This is useful when
>> 1432 torture-testing RCU, but in almost no other circumstance.
>> 1433
>> 1434 Say Y here if you want your system to crash and hang more often.
>> 1435 Say N if you want a sane system.
>> 1436
>> 1437 config RCU_TORTURE_TEST_SLOW_CLEANUP_DELAY
>> 1438 int "How much to slow down RCU grace-period cleanup"
>> 1439 range 0 5
>> 1440 default 3
>> 1441 depends on RCU_TORTURE_TEST_SLOW_CLEANUP
>> 1442 help
>> 1443 This option specifies the number of jiffies to wait between
>> 1444 each rcu_node structure cleanup operation.
>> 1445
>> 1446 config RCU_CPU_STALL_TIMEOUT
>> 1447 int "RCU CPU stall timeout in seconds"
>> 1448 depends on RCU_STALL_COMMON
>> 1449 range 3 300
>> 1450 default 21
>> 1451 help
>> 1452 If a given RCU grace period extends more than the specified
>> 1453 number of seconds, a CPU stall warning is printed. If the
>> 1454 RCU grace period persists, additional CPU stall warnings are
>> 1455 printed at more widely spaced intervals.
>> 1456
>> 1457 config RCU_TRACE
>> 1458 bool "Enable tracing for RCU"
>> 1459 depends on DEBUG_KERNEL
>> 1460 select TRACE_CLOCK
>> 1461 help
>> 1462 This option provides tracing in RCU which presents stats
>> 1463 in debugfs for debugging RCU implementation.
1795 1464
1796 source "kernel/rcu/Kconfig.debug" !! 1465 Say Y here if you want to enable RCU tracing
>> 1466 Say N if you are unsure.
>> 1467
>> 1468 config RCU_EQS_DEBUG
>> 1469 bool "Provide debugging asserts for adding NO_HZ support to an arch"
>> 1470 depends on DEBUG_KERNEL
>> 1471 help
>> 1472 This option provides consistency checks in RCU's handling of
>> 1473 NO_HZ. These checks have proven quite helpful in detecting
>> 1474 bugs in arch-specific NO_HZ code.
>> 1475
>> 1476 Say N here if you need ultimate kernel/user switch latencies
>> 1477 Say Y if you are unsure
>> 1478
>> 1479 endmenu # "RCU Debugging"
1797 1480
1798 config DEBUG_WQ_FORCE_RR_CPU 1481 config DEBUG_WQ_FORCE_RR_CPU
1799 bool "Force round-robin CPU selection 1482 bool "Force round-robin CPU selection for unbound work items"
1800 depends on DEBUG_KERNEL 1483 depends on DEBUG_KERNEL
1801 default n 1484 default n
1802 help 1485 help
1803 Workqueue used to implicitly guaran 1486 Workqueue used to implicitly guarantee that work items queued
1804 without explicit CPU specified are 1487 without explicit CPU specified are put on the local CPU. This
1805 guarantee is no longer true and whi 1488 guarantee is no longer true and while local CPU is still
1806 preferred work items may be put on 1489 preferred work items may be put on foreign CPUs. Kernel
1807 parameter "workqueue.debug_force_rr 1490 parameter "workqueue.debug_force_rr_cpu" is added to force
1808 round-robin CPU selection to flush 1491 round-robin CPU selection to flush out usages which depend on the
1809 now broken guarantee. This config 1492 now broken guarantee. This config option enables the debug
1810 feature by default. When enabled, 1493 feature by default. When enabled, memory and cache locality will
1811 be impacted. 1494 be impacted.
1812 1495
>> 1496 config DEBUG_BLOCK_EXT_DEVT
>> 1497 bool "Force extended block device numbers and spread them"
>> 1498 depends on DEBUG_KERNEL
>> 1499 depends on BLOCK
>> 1500 default n
>> 1501 help
>> 1502 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
>> 1503 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
>> 1504 YOU ARE DOING. Distros, please enable this and fix whatever
>> 1505 is broken.
>> 1506
>> 1507 Conventionally, block device numbers are allocated from
>> 1508 predetermined contiguous area. However, extended block area
>> 1509 may introduce non-contiguous block device numbers. This
>> 1510 option forces most block device numbers to be allocated from
>> 1511 the extended space and spreads them to discover kernel or
>> 1512 userland code paths which assume predetermined contiguous
>> 1513 device number allocation.
>> 1514
>> 1515 Note that turning on this debug option shuffles all the
>> 1516 device numbers for all IDE and SCSI devices including libata
>> 1517 ones, so root partition specified using device number
>> 1518 directly (via rdev or root=MAJ:MIN) won't work anymore.
>> 1519 Textual device names (root=/dev/sdXn) will continue to work.
>> 1520
>> 1521 Say N if you are unsure.
>> 1522
1813 config CPU_HOTPLUG_STATE_CONTROL 1523 config CPU_HOTPLUG_STATE_CONTROL
1814 bool "Enable CPU hotplug state contro 1524 bool "Enable CPU hotplug state control"
1815 depends on DEBUG_KERNEL 1525 depends on DEBUG_KERNEL
1816 depends on HOTPLUG_CPU 1526 depends on HOTPLUG_CPU
1817 default n 1527 default n
1818 help 1528 help
1819 Allows to write steps between "offl 1529 Allows to write steps between "offline" and "online" to the CPUs
1820 sysfs target file so states can be 1530 sysfs target file so states can be stepped granular. This is a debug
1821 option for now as the hotplug machi 1531 option for now as the hotplug machinery cannot be stopped and
1822 restarted at arbitrary points yet. 1532 restarted at arbitrary points yet.
1823 1533
1824 Say N if your are unsure. 1534 Say N if your are unsure.
1825 1535
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 1536 config NOTIFIER_ERROR_INJECTION
1933 tristate "Notifier error injection" 1537 tristate "Notifier error injection"
1934 depends on DEBUG_KERNEL 1538 depends on DEBUG_KERNEL
1935 select DEBUG_FS 1539 select DEBUG_FS
1936 help 1540 help
1937 This option provides the ability to 1541 This option provides the ability to inject artificial errors to
1938 specified notifier chain callbacks. 1542 specified notifier chain callbacks. It is useful to test the error
1939 handling of notifier call chain fai 1543 handling of notifier call chain failures.
1940 1544
1941 Say N if unsure. 1545 Say N if unsure.
1942 1546
>> 1547 config CPU_NOTIFIER_ERROR_INJECT
>> 1548 tristate "CPU notifier error injection module"
>> 1549 depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
>> 1550 help
>> 1551 This option provides a kernel module that can be used to test
>> 1552 the error handling of the cpu notifiers by injecting artificial
>> 1553 errors to CPU notifier chain callbacks. It is controlled through
>> 1554 debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu
>> 1555
>> 1556 If the notifier call chain should be failed with some events
>> 1557 notified, write the error code to "actions/<notifier event>/error".
>> 1558
>> 1559 Example: Inject CPU offline error (-1 == -EPERM)
>> 1560
>> 1561 # cd /sys/kernel/debug/notifier-error-inject/cpu
>> 1562 # echo -1 > actions/CPU_DOWN_PREPARE/error
>> 1563 # echo 0 > /sys/devices/system/cpu/cpu1/online
>> 1564 bash: echo: write error: Operation not permitted
>> 1565
>> 1566 To compile this code as a module, choose M here: the module will
>> 1567 be called cpu-notifier-error-inject.
>> 1568
>> 1569 If unsure, say N.
>> 1570
1943 config PM_NOTIFIER_ERROR_INJECT 1571 config PM_NOTIFIER_ERROR_INJECT
1944 tristate "PM notifier error injection 1572 tristate "PM notifier error injection module"
1945 depends on PM && NOTIFIER_ERROR_INJEC 1573 depends on PM && NOTIFIER_ERROR_INJECTION
1946 default m if PM_DEBUG 1574 default m if PM_DEBUG
1947 help 1575 help
1948 This option provides the ability to 1576 This option provides the ability to inject artificial errors to
1949 PM notifier chain callbacks. It is 1577 PM notifier chain callbacks. It is controlled through debugfs
1950 interface /sys/kernel/debug/notifie 1578 interface /sys/kernel/debug/notifier-error-inject/pm
1951 1579
1952 If the notifier call chain should b 1580 If the notifier call chain should be failed with some events
1953 notified, write the error code to " 1581 notified, write the error code to "actions/<notifier event>/error".
1954 1582
1955 Example: Inject PM suspend error (- 1583 Example: Inject PM suspend error (-12 = -ENOMEM)
1956 1584
1957 # cd /sys/kernel/debug/notifier-err 1585 # cd /sys/kernel/debug/notifier-error-inject/pm/
1958 # echo -12 > actions/PM_SUSPEND_PRE 1586 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1959 # echo mem > /sys/power/state 1587 # echo mem > /sys/power/state
1960 bash: echo: write error: Cannot all 1588 bash: echo: write error: Cannot allocate memory
1961 1589
1962 To compile this code as a module, c 1590 To compile this code as a module, choose M here: the module will
1963 be called pm-notifier-error-inject. 1591 be called pm-notifier-error-inject.
1964 1592
1965 If unsure, say N. 1593 If unsure, say N.
1966 1594
1967 config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1595 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1968 tristate "OF reconfig notifier error 1596 tristate "OF reconfig notifier error injection module"
1969 depends on OF_DYNAMIC && NOTIFIER_ERR 1597 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1970 help 1598 help
1971 This option provides the ability to 1599 This option provides the ability to inject artificial errors to
1972 OF reconfig notifier chain callback 1600 OF reconfig notifier chain callbacks. It is controlled
1973 through debugfs interface under 1601 through debugfs interface under
1974 /sys/kernel/debug/notifier-error-in 1602 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1975 1603
1976 If the notifier call chain should b 1604 If the notifier call chain should be failed with some events
1977 notified, write the error code to " 1605 notified, write the error code to "actions/<notifier event>/error".
1978 1606
1979 To compile this code as a module, c 1607 To compile this code as a module, choose M here: the module will
1980 be called of-reconfig-notifier-erro 1608 be called of-reconfig-notifier-error-inject.
1981 1609
1982 If unsure, say N. 1610 If unsure, say N.
1983 1611
1984 config NETDEV_NOTIFIER_ERROR_INJECT 1612 config NETDEV_NOTIFIER_ERROR_INJECT
1985 tristate "Netdev notifier error injec 1613 tristate "Netdev notifier error injection module"
1986 depends on NET && NOTIFIER_ERROR_INJE 1614 depends on NET && NOTIFIER_ERROR_INJECTION
1987 help 1615 help
1988 This option provides the ability to 1616 This option provides the ability to inject artificial errors to
1989 netdevice notifier chain callbacks. 1617 netdevice notifier chain callbacks. It is controlled through debugfs
1990 interface /sys/kernel/debug/notifie 1618 interface /sys/kernel/debug/notifier-error-inject/netdev
1991 1619
1992 If the notifier call chain should b 1620 If the notifier call chain should be failed with some events
1993 notified, write the error code to " 1621 notified, write the error code to "actions/<notifier event>/error".
1994 1622
1995 Example: Inject netdevice mtu chang 1623 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1996 1624
1997 # cd /sys/kernel/debug/notifier-err 1625 # cd /sys/kernel/debug/notifier-error-inject/netdev
1998 # echo -22 > actions/NETDEV_CHANGEM 1626 # echo -22 > actions/NETDEV_CHANGEMTU/error
1999 # ip link set eth0 mtu 1024 1627 # ip link set eth0 mtu 1024
2000 RTNETLINK answers: Invalid argument 1628 RTNETLINK answers: Invalid argument
2001 1629
2002 To compile this code as a module, c 1630 To compile this code as a module, choose M here: the module will
2003 be called netdev-notifier-error-inj 1631 be called netdev-notifier-error-inject.
2004 1632
2005 If unsure, say N. 1633 If unsure, say N.
2006 1634
2007 config FUNCTION_ERROR_INJECTION <<
2008 bool "Fault-injections of functions" <<
2009 depends on HAVE_FUNCTION_ERROR_INJECT <<
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 <<
2017 config FAULT_INJECTION 1635 config FAULT_INJECTION
2018 bool "Fault-injection framework" 1636 bool "Fault-injection framework"
2019 depends on DEBUG_KERNEL 1637 depends on DEBUG_KERNEL
2020 help 1638 help
2021 Provide fault-injection framework. 1639 Provide fault-injection framework.
2022 For more details, see Documentation 1640 For more details, see Documentation/fault-injection/.
2023 1641
2024 config FAILSLAB 1642 config FAILSLAB
2025 bool "Fault-injection capability for 1643 bool "Fault-injection capability for kmalloc"
2026 depends on FAULT_INJECTION 1644 depends on FAULT_INJECTION
>> 1645 depends on SLAB || SLUB
2027 help 1646 help
2028 Provide fault-injection capability 1647 Provide fault-injection capability for kmalloc.
2029 1648
2030 config FAIL_PAGE_ALLOC 1649 config FAIL_PAGE_ALLOC
2031 bool "Fault-injection capability for !! 1650 bool "Fault-injection capabilitiy for alloc_pages()"
2032 depends on FAULT_INJECTION 1651 depends on FAULT_INJECTION
2033 help 1652 help
2034 Provide fault-injection capability 1653 Provide fault-injection capability for alloc_pages().
2035 1654
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 1655 config FAIL_MAKE_REQUEST
2044 bool "Fault-injection capability for 1656 bool "Fault-injection capability for disk IO"
2045 depends on FAULT_INJECTION && BLOCK 1657 depends on FAULT_INJECTION && BLOCK
2046 help 1658 help
2047 Provide fault-injection capability 1659 Provide fault-injection capability for disk IO.
2048 1660
2049 config FAIL_IO_TIMEOUT 1661 config FAIL_IO_TIMEOUT
2050 bool "Fault-injection capability for 1662 bool "Fault-injection capability for faking disk interrupts"
2051 depends on FAULT_INJECTION && BLOCK 1663 depends on FAULT_INJECTION && BLOCK
2052 help 1664 help
2053 Provide fault-injection capability 1665 Provide fault-injection capability on end IO handling. This
2054 will make the block layer "forget" 1666 will make the block layer "forget" an interrupt as configured,
2055 thus exercising the error handling. 1667 thus exercising the error handling.
2056 1668
2057 Only works with drivers that use th 1669 Only works with drivers that use the generic timeout handling,
2058 for others it won't do anything. !! 1670 for others it wont do anything.
2059 <<
2060 config FAIL_FUTEX <<
2061 bool "Fault-injection capability for <<
2062 select DEBUG_FS <<
2063 depends on FAULT_INJECTION && FUTEX <<
2064 help <<
2065 Provide fault-injection capability <<
2066 <<
2067 config FAULT_INJECTION_DEBUG_FS <<
2068 bool "Debugfs entries for fault-injec <<
2069 depends on FAULT_INJECTION && SYSFS & <<
2070 help <<
2071 Enable configuration of fault-injec <<
2072 <<
2073 config FAIL_FUNCTION <<
2074 bool "Fault-injection capability for <<
2075 depends on FAULT_INJECTION_DEBUG_FS & <<
2076 help <<
2077 Provide function-based fault-inject <<
2078 This will allow you to override a s <<
2079 with given return value. As a resul <<
2080 an error value and have to handle i <<
2081 error handling in various subsystem <<
2082 1671
2083 config FAIL_MMC_REQUEST 1672 config FAIL_MMC_REQUEST
2084 bool "Fault-injection capability for 1673 bool "Fault-injection capability for MMC IO"
2085 depends on FAULT_INJECTION_DEBUG_FS & 1674 depends on FAULT_INJECTION_DEBUG_FS && MMC
2086 help 1675 help
2087 Provide fault-injection capability 1676 Provide fault-injection capability for MMC IO.
2088 This will make the mmc core return 1677 This will make the mmc core return data errors. This is
2089 useful to test the error handling i 1678 useful to test the error handling in the mmc block device
2090 and to test how the mmc host driver 1679 and to test how the mmc host driver handles retries from
2091 the block device. 1680 the block device.
2092 1681
2093 config FAIL_SUNRPC !! 1682 config FAIL_FUTEX
2094 bool "Fault-injection capability for !! 1683 bool "Fault-injection capability for futexes"
2095 depends on FAULT_INJECTION_DEBUG_FS & !! 1684 select DEBUG_FS
>> 1685 depends on FAULT_INJECTION && FUTEX
2096 help 1686 help
2097 Provide fault-injection capability !! 1687 Provide fault-injection capability for futexes.
2098 its consumers. <<
2099 1688
2100 config FAULT_INJECTION_CONFIGFS !! 1689 config FAULT_INJECTION_DEBUG_FS
2101 bool "Configfs interface for fault-in !! 1690 bool "Debugfs entries for fault-injection capabilities"
2102 depends on FAULT_INJECTION !! 1691 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2103 select CONFIGFS_FS <<
2104 help 1692 help
2105 This option allows configfs-based d !! 1693 Enable configuration of fault-injection capabilities via debugfs.
2106 fault-injection via configfs. Each <<
2107 fault-injection can be made visible <<
2108 configfs group. <<
2109 <<
2110 1694
2111 config FAULT_INJECTION_STACKTRACE_FILTER 1695 config FAULT_INJECTION_STACKTRACE_FILTER
2112 bool "stacktrace filter for fault-inj 1696 bool "stacktrace filter for fault-injection capabilities"
2113 depends on FAULT_INJECTION !! 1697 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2114 depends on (FAULT_INJECTION_DEBUG_FS !! 1698 depends on !X86_64
2115 select STACKTRACE 1699 select STACKTRACE
2116 depends on FRAME_POINTER || MIPS || P !! 1700 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !SCORE
2117 help 1701 help
2118 Provide stacktrace filter for fault 1702 Provide stacktrace filter for fault-injection capabilities
2119 1703
2120 config ARCH_HAS_KCOV !! 1704 config LATENCYTOP
2121 bool !! 1705 bool "Latency measuring infrastructure"
2122 help !! 1706 depends on DEBUG_KERNEL
2123 An architecture should select this !! 1707 depends on STACKTRACE_SUPPORT
2124 build and run with CONFIG_KCOV. Thi !! 1708 depends on PROC_FS
2125 disabling instrumentation for some !! 1709 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC
2126 !! 1710 select KALLSYMS
2127 config CC_HAS_SANCOV_TRACE_PC !! 1711 select KALLSYMS_ALL
2128 def_bool $(cc-option,-fsanitize-cover !! 1712 select STACKTRACE
2129 !! 1713 select SCHEDSTATS
2130 !! 1714 select SCHED_DEBUG
2131 config KCOV <<
2132 bool "Code coverage for fuzzing" <<
2133 depends on ARCH_HAS_KCOV <<
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 <<
2141 KCOV exposes kernel code coverage i <<
2142 for coverage-guided fuzzing (random <<
2143 <<
2144 For more details, see Documentation <<
2145 <<
2146 config KCOV_ENABLE_COMPARISONS <<
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 <<
2156 config KCOV_INSTRUMENT_ALL <<
2157 bool "Instrument all code by default" <<
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 <<
2167 config KCOV_IRQ_AREA_SIZE <<
2168 hex "Size of interrupt coverage colle <<
2169 depends on KCOV <<
2170 default 0x40000 <<
2171 help <<
2172 KCOV uses preallocated per-cpu area <<
2173 soft interrupts. This specifies the <<
2174 number of unsigned long words. <<
2175 <<
2176 menuconfig RUNTIME_TESTING_MENU <<
2177 bool "Runtime Testing" <<
2178 default y <<
2179 <<
2180 if RUNTIME_TESTING_MENU <<
2181 <<
2182 config TEST_DHRY <<
2183 tristate "Dhrystone benchmark test" <<
2184 help 1715 help
2185 Enable this to include the Dhryston !! 1716 Enable this option if you want to use the LatencyTOP tool
2186 calculates the number of Dhrystones !! 1717 to find out which userspace is blocking on what kernel operations.
2187 DMIPS (Dhrystone MIPS) obtained whe <<
2188 by 1757 (the number of Dhrystones p <<
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 <<
2199 Set number of iterations from kerne <<
2200 <<
2201 test_dhry.iterations=<n> <<
2202 <<
2203 Set number of iterations from users <<
2204 <<
2205 echo <n> > /sys/module/test_dhr <<
2206 <<
2207 Trigger manual run from userspace: <<
2208 <<
2209 echo y > /sys/module/test_dhry/ <<
2210 1718
2211 If the number of iterations is <= 0 !! 1719 source kernel/trace/Kconfig
2212 number of iterations (test runs for <<
2213 This process takes ca. 4s. <<
2214 1720
2215 If unsure, say N. !! 1721 menu "Runtime Testing"
2216 1722
2217 config LKDTM 1723 config LKDTM
2218 tristate "Linux Kernel Dump Test Tool 1724 tristate "Linux Kernel Dump Test Tool Module"
2219 depends on DEBUG_FS 1725 depends on DEBUG_FS
>> 1726 depends on BLOCK
>> 1727 default n
2220 help 1728 help
2221 This module enables testing of the di 1729 This module enables testing of the different dumping mechanisms by
2222 inducing system failures at predefine 1730 inducing system failures at predefined crash points.
2223 If you don't need it: say N 1731 If you don't need it: say N
2224 Choose M here to compile this code as 1732 Choose M here to compile this code as a module. The module will be
2225 called lkdtm. 1733 called lkdtm.
2226 1734
2227 Documentation on how to use the modul 1735 Documentation on how to use the module can be found in
2228 Documentation/fault-injection/provoke !! 1736 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 1737
2242 config TEST_LIST_SORT 1738 config TEST_LIST_SORT
2243 tristate "Linked list sorting test" i !! 1739 bool "Linked list sorting test"
2244 depends on KUNIT !! 1740 depends on DEBUG_KERNEL
2245 default KUNIT_ALL_TESTS <<
2246 help 1741 help
2247 Enable this to turn on 'list_sort() 1742 Enable this to turn on 'list_sort()' function test. This test is
2248 executed only once during system bo !! 1743 executed only once during system boot, so affects only boot time.
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 <<
2256 help <<
2257 Enable this to turn on min heap fun <<
2258 executed only once during system bo <<
2259 or at module load time. <<
2260 <<
2261 If unsure, say N. <<
2262 <<
2263 config TEST_SORT <<
2264 tristate "Array-based sort test" if ! <<
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 <<
2276 help <<
2277 Enable this to turn on 'do_div()' f <<
2278 executed only once during system bo <<
2279 or at module load time. <<
2280 <<
2281 If unsure, say N. <<
2282 <<
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 1744
2293 If unsure, say N. 1745 If unsure, say N.
2294 1746
2295 config KPROBES_SANITY_TEST 1747 config KPROBES_SANITY_TEST
2296 tristate "Kprobes sanity tests" if !K !! 1748 bool "Kprobes sanity tests"
2297 depends on DEBUG_KERNEL 1749 depends on DEBUG_KERNEL
2298 depends on KPROBES 1750 depends on KPROBES
2299 depends on KUNIT !! 1751 default n
2300 select STACKTRACE if ARCH_CORRECT_STA <<
2301 default KUNIT_ALL_TESTS <<
2302 help 1752 help
2303 This option provides for testing ba 1753 This option provides for testing basic kprobes functionality on
2304 boot. Samples of kprobe and kretpro !! 1754 boot. A sample kprobe, jprobe and kretprobe are inserted and
2305 verified for functionality. 1755 verified for functionality.
2306 1756
2307 Say N if you are unsure. 1757 Say N if you are unsure.
2308 1758
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 1759 config BACKTRACE_SELF_TEST
2322 tristate "Self test for the backtrace 1760 tristate "Self test for the backtrace code"
2323 depends on DEBUG_KERNEL 1761 depends on DEBUG_KERNEL
>> 1762 default n
2324 help 1763 help
2325 This option provides a kernel modul 1764 This option provides a kernel module that can be used to test
2326 the kernel stack backtrace code. Th 1765 the kernel stack backtrace code. This option is not useful
2327 for distributions or general kernel 1766 for distributions or general kernels, but only for kernel
2328 developers working on architecture 1767 developers working on architecture code.
2329 1768
2330 Note that if you want to also test 1769 Note that if you want to also test saved backtraces, you will
2331 have to enable STACKTRACE as well. 1770 have to enable STACKTRACE as well.
2332 1771
2333 Say N if you are unsure. 1772 Say N if you are unsure.
2334 1773
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 1774 config RBTREE_TEST
2346 tristate "Red-Black tree test" 1775 tristate "Red-Black tree test"
2347 depends on DEBUG_KERNEL 1776 depends on DEBUG_KERNEL
2348 help 1777 help
2349 A benchmark measuring the performan 1778 A benchmark measuring the performance of the rbtree library.
2350 Also includes rbtree invariant chec 1779 Also includes rbtree invariant checks.
2351 1780
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 1781 config INTERVAL_TREE_TEST
2365 tristate "Interval tree test" 1782 tristate "Interval tree test"
2366 depends on DEBUG_KERNEL !! 1783 depends on m && DEBUG_KERNEL
2367 select INTERVAL_TREE 1784 select INTERVAL_TREE
2368 help 1785 help
2369 A benchmark measuring the performan 1786 A benchmark measuring the performance of the interval tree library
2370 1787
2371 config PERCPU_TEST 1788 config PERCPU_TEST
2372 tristate "Per cpu operations test" 1789 tristate "Per cpu operations test"
2373 depends on m && DEBUG_KERNEL 1790 depends on m && DEBUG_KERNEL
2374 help 1791 help
2375 Enable this option to build test mo 1792 Enable this option to build test module which validates per-cpu
2376 operations. 1793 operations.
2377 1794
2378 If unsure, say N. 1795 If unsure, say N.
2379 1796
2380 config ATOMIC64_SELFTEST 1797 config ATOMIC64_SELFTEST
2381 tristate "Perform an atomic64_t self- !! 1798 bool "Perform an atomic64_t self-test at boot"
2382 help 1799 help
2383 Enable this option to test the atom !! 1800 Enable this option to test the atomic64_t functions at boot.
2384 at module load time. <<
2385 1801
2386 If unsure, say N. 1802 If unsure, say N.
2387 1803
2388 config ASYNC_RAID6_TEST 1804 config ASYNC_RAID6_TEST
2389 tristate "Self test for hardware acce 1805 tristate "Self test for hardware accelerated raid6 recovery"
2390 depends on ASYNC_RAID6_RECOV 1806 depends on ASYNC_RAID6_RECOV
2391 select ASYNC_MEMCPY 1807 select ASYNC_MEMCPY
2392 help !! 1808 ---help---
2393 This is a one-shot self test that p 1809 This is a one-shot self test that permutes through the
2394 recovery of all the possible two di 1810 recovery of all the possible two disk failure scenarios for a
2395 N-disk array. Recovery is performe 1811 N-disk array. Recovery is performed with the asynchronous
2396 raid6 recovery routines, and will o 1812 raid6 recovery routines, and will optionally use an offload
2397 engine if one is available. 1813 engine if one is available.
2398 1814
2399 If unsure, say N. 1815 If unsure, say N.
2400 1816
2401 config TEST_HEXDUMP 1817 config TEST_HEXDUMP
2402 tristate "Test functions located in t 1818 tristate "Test functions located in the hexdump module at runtime"
2403 1819
2404 config STRING_KUNIT_TEST !! 1820 config TEST_STRING_HELPERS
2405 tristate "KUnit test string functions !! 1821 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 1822
2414 config TEST_KSTRTOX 1823 config TEST_KSTRTOX
2415 tristate "Test kstrto*() family of fu 1824 tristate "Test kstrto*() family of functions at runtime"
2416 1825
2417 config TEST_PRINTF 1826 config TEST_PRINTF
2418 tristate "Test printf() family of fun 1827 tristate "Test printf() family of functions at runtime"
2419 1828
2420 config TEST_SCANF <<
2421 tristate "Test scanf() family of func <<
2422 <<
2423 config TEST_BITMAP 1829 config TEST_BITMAP
2424 tristate "Test bitmap_*() family of f 1830 tristate "Test bitmap_*() family of functions at runtime"
>> 1831 default n
2425 help 1832 help
2426 Enable this option to test the bitm 1833 Enable this option to test the bitmap functions at boot.
2427 1834
2428 If unsure, say N. 1835 If unsure, say N.
2429 1836
2430 config TEST_UUID 1837 config TEST_UUID
2431 tristate "Test functions located in t 1838 tristate "Test functions located in the uuid module at runtime"
2432 1839
2433 config TEST_XARRAY <<
2434 tristate "Test the XArray code at run <<
2435 <<
2436 config TEST_MAPLE_TREE <<
2437 tristate "Test the Maple Tree code at <<
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 <<
2445 config TEST_RHASHTABLE 1840 config TEST_RHASHTABLE
2446 tristate "Perform selftest on resizab 1841 tristate "Perform selftest on resizable hash table"
>> 1842 default n
2447 help 1843 help
2448 Enable this option to test the rhas 1844 Enable this option to test the rhashtable functions at boot.
2449 1845
2450 If unsure, say N. 1846 If unsure, say N.
2451 1847
2452 config TEST_IDA !! 1848 config TEST_HASH
2453 tristate "Perform selftest on IDA fun !! 1849 tristate "Perform selftest on hash functions"
2454 !! 1850 default n
2455 config TEST_PARMAN <<
2456 tristate "Perform selftest on priorit <<
2457 depends on PARMAN <<
2458 help 1851 help
2459 Enable this option to test priority !! 1852 Enable this option to test the kernel's integer (<linux/hash.h>),
2460 (or module load). !! 1853 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
>> 1854 hash functions on boot (or module load).
2461 1855
2462 If unsure, say N. !! 1856 This is intended to help people writing architecture-specific
>> 1857 optimized versions. If unsure, say N.
2463 1858
2464 config TEST_IRQ_TIMINGS !! 1859 endmenu # runtime tests
2465 bool "IRQ timings selftest" !! 1860
2466 depends on IRQ_TIMINGS !! 1861 config PROVIDE_OHCI1394_DMA_INIT
>> 1862 bool "Remote debugging over FireWire early on boot"
>> 1863 depends on PCI && X86
2467 help 1864 help
2468 Enable this option to test the irq !! 1865 If you want to debug problems which hang or crash the kernel early
>> 1866 on boot and the crashing machine has a FireWire port, you can use
>> 1867 this feature to remotely access the memory of the crashed machine
>> 1868 over FireWire. This employs remote DMA as part of the OHCI1394
>> 1869 specification which is now the standard for FireWire controllers.
>> 1870
>> 1871 With remote DMA, you can monitor the printk buffer remotely using
>> 1872 firescope and access all memory below 4GB using fireproxy from gdb.
>> 1873 Even controlling a kernel debugger is possible using remote DMA.
>> 1874
>> 1875 Usage:
>> 1876
>> 1877 If ohci1394_dma=early is used as boot parameter, it will initialize
>> 1878 all OHCI1394 controllers which are found in the PCI config space.
>> 1879
>> 1880 As all changes to the FireWire bus such as enabling and disabling
>> 1881 devices cause a bus reset and thereby disable remote DMA for all
>> 1882 devices, be sure to have the cable plugged and FireWire enabled on
>> 1883 the debugging host before booting the debug target for debugging.
>> 1884
>> 1885 This code (~1k) is freed after boot. By then, the firewire stack
>> 1886 in charge of the OHCI-1394 controllers should be used instead.
>> 1887
>> 1888 See Documentation/debugging-via-ohci1394.txt for more information.
>> 1889
>> 1890 config DMA_API_DEBUG
>> 1891 bool "Enable debugging of DMA-API usage"
>> 1892 depends on HAVE_DMA_API_DEBUG
>> 1893 help
>> 1894 Enable this option to debug the use of the DMA API by device drivers.
>> 1895 With this option you will be able to detect common bugs in device
>> 1896 drivers like double-freeing of DMA mappings or freeing mappings that
>> 1897 were never allocated.
>> 1898
>> 1899 This also attempts to catch cases where a page owned by DMA is
>> 1900 accessed by the cpu in a way that could cause data corruption. For
>> 1901 example, this enables cow_user_page() to check that the source page is
>> 1902 not undergoing DMA.
>> 1903
>> 1904 This option causes a performance degradation. Use only if you want to
>> 1905 debug device drivers and dma interactions.
2469 1906
2470 If unsure, say N. 1907 If unsure, say N.
2471 1908
2472 config TEST_LKM 1909 config TEST_LKM
2473 tristate "Test module loading with 'h 1910 tristate "Test module loading with 'hello world' module"
>> 1911 default n
2474 depends on m 1912 depends on m
2475 help 1913 help
2476 This builds the "test_module" modul 1914 This builds the "test_module" module that emits "Hello, world"
2477 on printk when loaded. It is design 1915 on printk when loaded. It is designed to be used for basic
2478 evaluation of the module loading su 1916 evaluation of the module loading subsystem (for example when
2479 validating module verification). It 1917 validating module verification). It lacks any extra dependencies,
2480 and will not normally be loaded by 1918 and will not normally be loaded by the system unless explicitly
2481 requested by name. 1919 requested by name.
2482 1920
2483 If unsure, say N. 1921 If unsure, say N.
2484 1922
2485 config TEST_BITOPS !! 1923 config TEST_USER_COPY
2486 tristate "Test module for compilation !! 1924 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 1925 default n
2500 depends on MMU <<
2501 depends on m 1926 depends on m
2502 help 1927 help
2503 This builds the "test_vmalloc" modu !! 1928 This builds the "test_user_copy" module that runs sanity checks
2504 stress and performance analysis. So !! 1929 on the copy_to/from_user infrastructure, making sure basic
2505 subsystem can be evaluated from per !! 1930 user/kernel boundary testing is working. If it fails to load,
2506 of view. !! 1931 a regression has been detected in the user/kernel memory boundary
>> 1932 protections.
2507 1933
2508 If unsure, say N. 1934 If unsure, say N.
2509 1935
2510 config TEST_BPF 1936 config TEST_BPF
2511 tristate "Test BPF filter functionali 1937 tristate "Test BPF filter functionality"
>> 1938 default n
2512 depends on m && NET 1939 depends on m && NET
2513 help 1940 help
2514 This builds the "test_bpf" module t 1941 This builds the "test_bpf" module that runs various test vectors
2515 against the BPF interpreter or BPF 1942 against the BPF interpreter or BPF JIT compiler depending on the
2516 current setting. This is in particu 1943 current setting. This is in particular useful for BPF JIT compiler
2517 development, but also to run regres 1944 development, but also to run regression tests against changes in
2518 the interpreter code. It also enabl 1945 the interpreter code. It also enables test stubs for eBPF maps and
2519 verifier used by user space verifie 1946 verifier used by user space verifier testsuite.
2520 1947
2521 If unsure, say N. 1948 If unsure, say N.
2522 1949
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 <<
2533 tristate "Test find_bit functions" <<
2534 help <<
2535 This builds the "test_find_bit" mod <<
2536 functions performance. <<
2537 <<
2538 If unsure, say N. <<
2539 <<
2540 config TEST_FIRMWARE 1950 config TEST_FIRMWARE
2541 tristate "Test firmware loading via u 1951 tristate "Test firmware loading via userspace interface"
>> 1952 default n
2542 depends on FW_LOADER 1953 depends on FW_LOADER
2543 help 1954 help
2544 This builds the "test_firmware" mod 1955 This builds the "test_firmware" module that creates a userspace
2545 interface for testing firmware load 1956 interface for testing firmware loading. This can be used to
2546 control the triggering of firmware 1957 control the triggering of firmware loading without needing an
2547 actual firmware-using device. The c 1958 actual firmware-using device. The contents can be rechecked by
2548 userspace. 1959 userspace.
2549 1960
2550 If unsure, say N. 1961 If unsure, say N.
2551 1962
2552 config TEST_SYSCTL <<
2553 tristate "sysctl test driver" <<
2554 depends on PROC_SYSCTL <<
2555 help <<
2556 This builds the "test_sysctl" modul <<
2557 proc sysctl interfaces available to <<
2558 production knobs which might alter <<
2559 <<
2560 If unsure, say N. <<
2561 <<
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 1963 config TEST_UDELAY
2817 tristate "udelay test driver" 1964 tristate "udelay test driver"
>> 1965 default n
2818 help 1966 help
2819 This builds the "udelay_test" modul 1967 This builds the "udelay_test" module that helps to make sure
2820 that udelay() is working properly. 1968 that udelay() is working properly.
2821 1969
2822 If unsure, say N. 1970 If unsure, say N.
2823 1971
2824 config TEST_STATIC_KEYS <<
2825 tristate "Test static keys" <<
2826 depends on m <<
2827 help <<
2828 Test the static key interfaces. <<
2829 <<
2830 If unsure, say N. <<
2831 <<
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 <<
2843 tristate "kmod stress tester" <<
2844 depends on m <<
2845 depends on NETDEVICES && NET_CORE && <<
2846 depends on BLOCK <<
2847 depends on PAGE_SIZE_LESS_THAN_256KB <<
2848 select TEST_LKM <<
2849 select XFS_FS <<
2850 select TUN <<
2851 select BTRFS_FS <<
2852 help <<
2853 Test the kernel's module loading me <<
2854 support to load modules using the L <<
2855 This test provides a series of test <<
2856 <<
2857 Although technically you can either <<
2858 into the kernel we disallow buildin <<
2859 it stress tests request_module() an <<
2860 some issues by taking over precious <<
2861 module load requests, ultimately th <<
2862 <<
2863 To run tests run: <<
2864 <<
2865 tools/testing/selftests/kmod/kmod.s <<
2866 <<
2867 If unsure, say N. <<
2868 <<
2869 config TEST_DEBUG_VIRTUAL <<
2870 tristate "Test CONFIG_DEBUG_VIRTUAL f <<
2871 depends on DEBUG_VIRTUAL <<
2872 help <<
2873 Test the kernel's ability to detect <<
2874 virt_to_phys() done against the non <<
2875 kernel's virtual address map. <<
2876 <<
2877 If unsure, say N. <<
2878 <<
2879 config TEST_MEMCAT_P <<
2880 tristate "Test memcat_p() helper func <<
2881 help <<
2882 Test the memcat_p() helper for corr <<
2883 pointer arrays together. <<
2884 <<
2885 If unsure, say N. <<
2886 <<
2887 config TEST_OBJAGG <<
2888 tristate "Perform selftest on object <<
2889 default n <<
2890 depends on OBJAGG <<
2891 help <<
2892 Enable this option to test object a <<
2893 (or module load). <<
2894 <<
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. <<
2958 <<
2959 endif # RUNTIME_TESTING_MENU <<
2960 <<
2961 config ARCH_USE_MEMTEST <<
2962 bool <<
2963 help <<
2964 An architecture should select this <<
2965 during boot process. <<
2966 <<
2967 config MEMTEST 1972 config MEMTEST
2968 bool "Memtest" 1973 bool "Memtest"
2969 depends on ARCH_USE_MEMTEST !! 1974 depends on HAVE_MEMBLOCK
2970 help !! 1975 ---help---
2971 This option adds a kernel parameter 1976 This option adds a kernel parameter 'memtest', which allows memtest
2972 to be set and executed. !! 1977 to be set.
2973 memtest=0, mean disabled; -- 1978 memtest=0, mean disabled; -- default
2974 memtest=1, mean do 1 test pat 1979 memtest=1, mean do 1 test pattern;
2975 ... 1980 ...
2976 memtest=17, mean do 17 test p 1981 memtest=17, mean do 17 test patterns.
2977 If you are unsure how to answer thi 1982 If you are unsure how to answer this question, answer N.
2978 1983
2979 !! 1984 config TEST_STATIC_KEYS
2980 !! 1985 tristate "Test static keys"
2981 config HYPERV_TESTING <<
2982 bool "Microsoft Hyper-V driver testin <<
2983 default n 1986 default n
2984 depends on HYPERV && DEBUG_FS !! 1987 depends on m
2985 help <<
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 1988 help
2996 Enables rustc's `-Cdebug-assertions !! 1989 Test the static key interfaces.
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 1990
3005 If unsure, say N. 1991 If unsure, say N.
3006 1992
3007 config RUST_OVERFLOW_CHECKS !! 1993 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 <<
3018 Note that this will apply to all Ru <<
3019 <<
3020 If unsure, say Y. <<
3021 1994
3022 config RUST_BUILD_ASSERT_ALLOW !! 1995 source "lib/Kconfig.kgdb"
3023 bool "Allow unoptimized build-time as <<
3024 depends on RUST <<
3025 help <<
3026 Controls how are `build_error!` and <<
3027 1996
3028 If calls to them exist in the binar !! 1997 source "lib/Kconfig.ubsan"
3029 or that the optimizer failed to ver <<
3030 1998
3031 This should not happen, thus by def !! 1999 config ARCH_HAS_DEVMEM_IS_ALLOWED
3032 as an escape hatch, you can choose !! 2000 bool
3033 and let the check be carried at run <<
3034 the check fails). <<
3035 2001
3036 If unsure, say N. !! 2002 config STRICT_DEVMEM
>> 2003 bool "Filter access to /dev/mem"
>> 2004 depends on MMU
>> 2005 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
>> 2006 default y if TILE || PPC
>> 2007 ---help---
>> 2008 If this option is disabled, you allow userspace (root) access to all
>> 2009 of memory, including kernel and userspace memory. Accidental
>> 2010 access to this is obviously disastrous, but specific access can
>> 2011 be used by people debugging the kernel. Note that with PAT support
>> 2012 enabled, even in this case there are restrictions on /dev/mem
>> 2013 use due to the cache aliasing requirements.
3037 2014
3038 config RUST_KERNEL_DOCTESTS !! 2015 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
3039 bool "Doctests for the `kernel` crate !! 2016 file only allows userspace access to PCI space and the BIOS code and
3040 depends on RUST && KUNIT=y !! 2017 data regions. This is sufficient for dosemu and X and all common
3041 default KUNIT_ALL_TESTS !! 2018 users of /dev/mem.
3042 help <<
3043 This builds the documentation tests <<
3044 as KUnit tests. <<
3045 2019
3046 For more information on KUnit and u !! 2020 If in doubt, say Y.
3047 please refer to the KUnit documenta <<
3048 2021
3049 If unsure, say N. !! 2022 config IO_STRICT_DEVMEM
>> 2023 bool "Filter I/O access to /dev/mem"
>> 2024 depends on STRICT_DEVMEM
>> 2025 ---help---
>> 2026 If this option is disabled, you allow userspace (root) access to all
>> 2027 io-memory regardless of whether a driver is actively using that
>> 2028 range. Accidental access to this is obviously disastrous, but
>> 2029 specific access can be used by people debugging kernel drivers.
3050 2030
3051 endmenu # "Rust" !! 2031 If this option is switched on, the /dev/mem file only allows
>> 2032 userspace access to *idle* io-memory ranges (see /proc/iomem) This
>> 2033 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
>> 2034 if the driver using a given range cannot be disabled.
3052 2035
3053 endmenu # Kernel hacking !! 2036 If in doubt, say Y.
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