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