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Thomas Gleixnerec8f24b2019-05-19 13:07:45 +01001# SPDX-License-Identifier: GPL-2.0-only
Christoph Hellwig06ec64b2018-07-31 13:39:31 +02002menu "Kernel hacking"
3
Dave Hansen604ff0d2013-07-01 13:04:49 -07004menu "printk and dmesg options"
Linus Torvalds1da177e2005-04-16 15:20:36 -07005
6config PRINTK_TIME
7 bool "Show timing information on printks"
Randy Dunlapd3b8b6e2006-12-06 20:36:38 -08008 depends on PRINTK
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 help
Kay Sievers649e6ee2012-05-10 04:30:45 +020010 Selecting this option causes time stamps of the printk()
11 messages to be added to the output of the syslog() system
12 call and at the console.
13
14 The timestamp is always recorded internally, and exported
15 to /dev/kmsg. This flag just specifies if the timestamp should
16 be included, not that the timestamp is recorded.
17
18 The behavior is also controlled by the kernel command line
Mauro Carvalho Chehab8c27ceff32016-10-18 10:12:27 -020019 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
Linus Torvalds1da177e2005-04-16 15:20:36 -070020
Tetsuo Handa15ff2062018-12-18 06:05:04 +090021config PRINTK_CALLER
22 bool "Show caller information on printks"
23 depends on PRINTK
24 help
25 Selecting this option causes printk() to add a caller "thread id" (if
26 in task context) or a caller "processor id" (if not in task context)
27 to every message.
28
29 This option is intended for environments where multiple threads
30 concurrently call printk() for many times, for it is difficult to
31 interpret without knowing where these lines (or sometimes individual
32 line which was divided into multiple lines due to race) came from.
33
34 Since toggling after boot makes the code racy, currently there is
35 no option to enable/disable at the kernel command line parameter or
36 sysfs interface.
37
Olof Johanssona8cfdc62016-12-12 16:45:56 -080038config CONSOLE_LOGLEVEL_DEFAULT
39 int "Default console loglevel (1-15)"
40 range 1 15
41 default "7"
42 help
43 Default loglevel to determine what will be printed on the console.
44
45 Setting a default here is equivalent to passing in loglevel=<x> in
46 the kernel bootargs. loglevel=<x> continues to override whatever
47 value is specified here as well.
48
Borislav Petkov50f4d9b2016-12-19 16:23:15 -080049 Note: This does not affect the log level of un-prefixed printk()
Olof Johanssona8cfdc62016-12-12 16:45:56 -080050 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
51 option.
52
Hans de Goede22eceb82018-06-19 13:57:26 +020053config CONSOLE_LOGLEVEL_QUIET
54 int "quiet console loglevel (1-15)"
55 range 1 15
56 default "4"
57 help
58 loglevel to use when "quiet" is passed on the kernel commandline.
59
60 When "quiet" is passed on the kernel commandline this loglevel
61 will be used as the loglevel. IOW passing "quiet" will be the
62 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
63
Alex Elder42a9dc02014-08-06 16:09:01 -070064config MESSAGE_LOGLEVEL_DEFAULT
Mandeep Singh Baines5af5bcb2011-03-22 16:34:23 -070065 int "Default message log level (1-7)"
66 range 1 7
67 default "4"
68 help
69 Default log level for printk statements with no specified priority.
70
71 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
72 that are auditing their logs closely may want to set it to a lower
73 priority.
74
Olof Johanssona8cfdc62016-12-12 16:45:56 -080075 Note: This does not affect what message level gets printed on the console
76 by default. To change that, use loglevel=<x> in the kernel bootargs,
77 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
78
Dave Hansen604ff0d2013-07-01 13:04:49 -070079config BOOT_PRINTK_DELAY
80 bool "Delay each boot printk message by N milliseconds"
81 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
82 help
83 This build option allows you to read kernel boot messages
84 by inserting a short delay after each one. The delay is
85 specified in milliseconds on the kernel command line,
86 using "boot_delay=N".
87
88 It is likely that you would also need to use "lpj=M" to preset
89 the "loops per jiffie" value.
90 See a previous boot log for the "lpj" value to use for your
91 system, and then set "lpj=M" before setting "boot_delay=N".
92 NOTE: Using this option may adversely affect SMP systems.
93 I.e., processors other than the first one may not boot up.
94 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
95 what it believes to be lockup conditions.
96
97config DYNAMIC_DEBUG
98 bool "Enable dynamic printk() support"
99 default n
100 depends on PRINTK
101 depends on DEBUG_FS
102 help
103
104 Compiles debug level messages into the kernel, which would not
105 otherwise be available at runtime. These messages can then be
106 enabled/disabled based on various levels of scope - per source file,
107 function, module, format string, and line number. This mechanism
108 implicitly compiles in all pr_debug() and dev_dbg() calls, which
109 enlarges the kernel text size by about 2%.
110
111 If a source file is compiled with DEBUG flag set, any
112 pr_debug() calls in it are enabled by default, but can be
113 disabled at runtime as below. Note that DEBUG flag is
114 turned on by many CONFIG_*DEBUG* options.
115
116 Usage:
117
118 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
119 which is contained in the 'debugfs' filesystem. Thus, the debugfs
120 filesystem must first be mounted before making use of this feature.
121 We refer the control file as: <debugfs>/dynamic_debug/control. This
122 file contains a list of the debug statements that can be enabled. The
123 format for each line of the file is:
124
125 filename:lineno [module]function flags format
126
127 filename : source file of the debug statement
128 lineno : line number of the debug statement
129 module : module that contains the debug statement
130 function : function that contains the debug statement
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800131 flags : '=p' means the line is turned 'on' for printing
132 format : the format used for the debug statement
Dave Hansen604ff0d2013-07-01 13:04:49 -0700133
134 From a live system:
135
136 nullarbor:~ # cat <debugfs>/dynamic_debug/control
137 # filename:lineno [module]function flags format
138 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
139 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
140 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
141
142 Example usage:
143
144 // enable the message at line 1603 of file svcsock.c
145 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
146 <debugfs>/dynamic_debug/control
147
148 // enable all the messages in file svcsock.c
149 nullarbor:~ # echo -n 'file svcsock.c +p' >
150 <debugfs>/dynamic_debug/control
151
152 // enable all the messages in the NFS server module
153 nullarbor:~ # echo -n 'module nfsd +p' >
154 <debugfs>/dynamic_debug/control
155
156 // enable all 12 messages in the function svc_process()
157 nullarbor:~ # echo -n 'func svc_process +p' >
158 <debugfs>/dynamic_debug/control
159
160 // disable all 12 messages in the function svc_process()
161 nullarbor:~ # echo -n 'func svc_process -p' >
162 <debugfs>/dynamic_debug/control
163
Hans Holmbergf8998c22017-03-16 09:37:32 +0100164 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
165 information.
Dave Hansen604ff0d2013-07-01 13:04:49 -0700166
Rasmus Villemoes57f56772019-10-15 21:07:05 +0200167config SYMBOLIC_ERRNAME
168 bool "Support symbolic error names in printf"
169 default y if PRINTK
170 help
171 If you say Y here, the kernel's printf implementation will
172 be able to print symbolic error names such as ENOSPC instead
173 of the number 28. It makes the kernel image slightly larger
174 (about 3KB), but can make the kernel logs easier to read.
175
Changbin Du2b05bb72019-12-06 17:04:03 -0800176config DEBUG_BUGVERBOSE
177 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
178 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
179 default y
180 help
181 Say Y here to make BUG() panics output the file name and line number
182 of the BUG call as well as the EIP and oops trace. This aids
183 debugging but costs about 70-100K of memory.
184
Dave Hansen604ff0d2013-07-01 13:04:49 -0700185endmenu # "printk and dmesg options"
186
Dave Hansen6dfc0662013-07-01 13:04:46 -0700187menu "Compile-time checks and compiler options"
188
189config DEBUG_INFO
190 bool "Compile the kernel with debug info"
Linus Torvalds12b13832014-02-04 12:20:01 -0800191 depends on DEBUG_KERNEL && !COMPILE_TEST
Dave Hansen6dfc0662013-07-01 13:04:46 -0700192 help
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800193 If you say Y here the resulting kernel image will include
Dave Hansen6dfc0662013-07-01 13:04:46 -0700194 debugging info resulting in a larger kernel image.
195 This adds debug symbols to the kernel and modules (gcc -g), and
196 is needed if you intend to use kernel crashdump or binary object
197 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
198 Say Y here only if you plan to debug the kernel.
199
200 If unsure, say N.
201
202config DEBUG_INFO_REDUCED
203 bool "Reduce debugging information"
204 depends on DEBUG_INFO
205 help
206 If you say Y here gcc is instructed to generate less debugging
207 information for structure types. This means that tools that
208 need full debugging information (like kgdb or systemtap) won't
209 be happy. But if you merely need debugging information to
210 resolve line numbers there is no loss. Advantage is that
211 build directory object sizes shrink dramatically over a full
212 DEBUG_INFO build and compile times are reduced too.
213 Only works with newer gcc versions.
214
Andi Kleen866ced92014-07-30 20:50:18 +0200215config DEBUG_INFO_SPLIT
216 bool "Produce split debuginfo in .dwo files"
Arnd Bergmanna687a532018-03-07 23:30:54 +0100217 depends on DEBUG_INFO
Masahiro Yamada9d937442019-02-22 16:56:09 +0900218 depends on $(cc-option,-gsplit-dwarf)
Andi Kleen866ced92014-07-30 20:50:18 +0200219 help
220 Generate debug info into separate .dwo files. This significantly
221 reduces the build directory size for builds with DEBUG_INFO,
222 because it stores the information only once on disk in .dwo
223 files instead of multiple times in object files and executables.
224 In addition the debug information is also compressed.
225
226 Requires recent gcc (4.7+) and recent gdb/binutils.
227 Any tool that packages or reads debug information would need
228 to know about the .dwo files and include them.
229 Incompatible with older versions of ccache.
230
Andi Kleenbfaf2dd2014-07-30 20:50:19 +0200231config DEBUG_INFO_DWARF4
232 bool "Generate dwarf4 debuginfo"
233 depends on DEBUG_INFO
Masahiro Yamada9d937442019-02-22 16:56:09 +0900234 depends on $(cc-option,-gdwarf-4)
Andi Kleenbfaf2dd2014-07-30 20:50:19 +0200235 help
236 Generate dwarf4 debug info. This requires recent versions
237 of gcc and gdb. It makes the debug information larger.
238 But it significantly improves the success of resolving
239 variables in gdb on optimized code.
240
Andrii Nakryikoe83b9f52019-04-02 09:49:50 -0700241config DEBUG_INFO_BTF
242 bool "Generate BTF typeinfo"
243 depends on DEBUG_INFO
Slava Bacherikov7d32e692020-04-02 23:41:39 +0300244 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
245 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
Andrii Nakryikoe83b9f52019-04-02 09:49:50 -0700246 help
247 Generate deduplicated BTF type information from DWARF debug info.
248 Turning this on expects presence of pahole tool, which will convert
249 DWARF type info into equivalent deduplicated BTF type info.
250
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800251config GDB_SCRIPTS
252 bool "Provide GDB scripts for kernel debugging"
253 depends on DEBUG_INFO
254 help
255 This creates the required links to GDB helper scripts in the
256 build directory. If you load vmlinux into gdb, the helper
257 scripts will be automatically imported by gdb as well, and
258 additional functions are available to analyze a Linux kernel
Andreas Platschek700199b02016-12-14 15:05:40 -0800259 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
260 for further details.
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800261
Andrew Mortoncebc04b2006-08-14 22:43:18 -0700262config ENABLE_MUST_CHECK
263 bool "Enable __must_check logic"
264 default y
265 help
266 Enable the __must_check logic in the kernel build. Disable this to
267 suppress the "warning: ignoring return value of 'foo', declared with
268 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269
Andi Kleen35bb5b12008-02-22 15:15:03 +0100270config FRAME_WARN
Masahiro Yamadaa83e4ca2020-02-17 00:19:36 +0900271 int "Warn for stack frames larger than"
Andi Kleen35bb5b12008-02-22 15:15:03 +0100272 range 0 8192
Kees Cook0e07f662016-10-27 17:46:41 -0700273 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
Helge Deller432654d2017-09-11 21:41:43 +0200274 default 1280 if (!64BIT && PARISC)
275 default 1024 if (!64BIT && !PARISC)
Andi Kleen35bb5b12008-02-22 15:15:03 +0100276 default 2048 if 64BIT
277 help
278 Tell gcc to warn at build time for stack frames larger than this.
279 Setting this too low will cause a lot of warnings.
280 Setting it to 0 disables the warning.
Andi Kleen35bb5b12008-02-22 15:15:03 +0100281
Randy Dunlap99657c72009-09-18 12:49:22 -0700282config STRIP_ASM_SYMS
283 bool "Strip assembler-generated symbols during link"
284 default n
285 help
286 Strip internal assembler-generated symbols during a link (symbols
287 that look like '.Lxxx') so they don't pollute the output of
288 get_wchan() and suchlike.
289
Andi Kleen1873e872012-03-28 11:51:18 -0700290config READABLE_ASM
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800291 bool "Generate readable assembler code"
292 depends on DEBUG_KERNEL
Don Mullisbf4735a2006-12-10 02:18:37 -0800293 help
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800294 Disable some compiler optimizations that tend to generate human unreadable
295 assembler output. This may make the kernel slightly slower, but it helps
296 to keep kernel developers who have to stare a lot at assembler listings
297 sane.
Don Mullisbf4735a2006-12-10 02:18:37 -0800298
Masahiro Yamadae949f4c2019-06-04 19:13:59 +0900299config HEADERS_INSTALL
300 bool "Install uapi headers to usr/include"
Don Mullisbf4735a2006-12-10 02:18:37 -0800301 depends on !UML
302 help
Masahiro Yamadae949f4c2019-06-04 19:13:59 +0900303 This option will install uapi headers (headers exported to user-space)
304 into the usr/include directory for use during the kernel build.
305 This is unneeded for building the kernel itself, but needed for some
306 user-space program samples. It is also needed by some features such
307 as uapi header sanity checks.
308
Masahiro Yamada9012d012019-05-14 15:42:25 -0700309config OPTIMIZE_INLINING
Masahiro Yamadaac7c3e42019-09-25 16:47:42 -0700310 def_bool y
Masahiro Yamada9012d012019-05-14 15:42:25 -0700311 help
312 This option determines if the kernel forces gcc to inline the functions
313 developers have marked 'inline'. Doing so takes away freedom from gcc to
314 do what it thinks is best, which is desirable for the gcc 3.x series of
315 compilers. The gcc 4.x series have a rewritten inlining algorithm and
316 enabling this option will generate a smaller kernel there. Hopefully
317 this algorithm is so good that allowing gcc 4.x and above to make the
318 decision will become the default in the future. Until then this option
319 is there to test gcc for this.
320
Sam Ravnborg91341d42008-01-21 21:31:44 +0100321config DEBUG_SECTION_MISMATCH
322 bool "Enable full Section mismatch analysis"
Sam Ravnborg91341d42008-01-21 21:31:44 +0100323 help
324 The section mismatch analysis checks if there are illegal
325 references from one section to another section.
Michael Wittene809ab02011-04-17 04:08:48 +0000326 During linktime or runtime, some sections are dropped;
327 any use of code/data previously in these sections would
Sam Ravnborg91341d42008-01-21 21:31:44 +0100328 most likely result in an oops.
Michael Wittene809ab02011-04-17 04:08:48 +0000329 In the code, functions and variables are annotated with
Paul Gortmaker0db06282013-06-19 14:53:51 -0400330 __init,, etc. (see the full list in include/linux/init.h),
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100331 which results in the code/data being placed in specific sections.
Michael Wittene809ab02011-04-17 04:08:48 +0000332 The section mismatch analysis is always performed after a full
333 kernel build, and enabling this option causes the following
Masahiro Yamadab7dca6d2019-07-17 15:17:57 +0900334 additional step to occur:
Michael Wittene809ab02011-04-17 04:08:48 +0000335 - Add the option -fno-inline-functions-called-once to gcc commands.
336 When inlining a function annotated with __init in a non-init
337 function, we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100338 the analysis would not catch the illegal reference.
Michael Wittene809ab02011-04-17 04:08:48 +0000339 This option tells gcc to inline less (but it does result in
340 a larger kernel).
Sam Ravnborg91341d42008-01-21 21:31:44 +0100341
Nicolas Boichat47490ec2015-10-06 09:44:42 +1030342config SECTION_MISMATCH_WARN_ONLY
343 bool "Make section mismatch errors non-fatal"
344 default y
345 help
346 If you say N here, the build process will fail if there are any
347 section mismatch, instead of just throwing warnings.
348
349 If unsure, say Y.
350
Dave Hansen6dfc0662013-07-01 13:04:46 -0700351#
352# Select this config option from the architecture Kconfig, if it
353# is preferred to always offer frame pointers as a config
354# option on the architecture (regardless of KERNEL_DEBUG):
355#
356config ARCH_WANT_FRAME_POINTERS
357 bool
Dave Hansen6dfc0662013-07-01 13:04:46 -0700358
359config FRAME_POINTER
360 bool "Compile the kernel with frame pointers"
Arnd Bergmanna687a532018-03-07 23:30:54 +0100361 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
Dave Hansen6dfc0662013-07-01 13:04:46 -0700362 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
363 help
364 If you say Y here the resulting kernel image will be slightly
365 larger and slower, but it gives very useful debugging information
366 in case of kernel bugs. (precise oopses/stacktraces/warnings)
367
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600368config STACK_VALIDATION
369 bool "Compile-time stack metadata validation"
370 depends on HAVE_STACK_VALIDATION
371 default n
372 help
373 Add compile-time checks to validate stack metadata, including frame
374 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
375 that runtime stack traces are more reliable.
376
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500377 This is also a prerequisite for generation of ORC unwind data, which
Josh Poimboeuf11af8472017-10-13 15:02:00 -0500378 is needed for CONFIG_UNWINDER_ORC.
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500379
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600380 For more information, see
381 tools/objtool/Documentation/stack-validation.txt.
382
Dave Hansen6dfc0662013-07-01 13:04:46 -0700383config DEBUG_FORCE_WEAK_PER_CPU
384 bool "Force weak per-cpu definitions"
385 depends on DEBUG_KERNEL
386 help
387 s390 and alpha require percpu variables in modules to be
388 defined weak to work around addressing range issue which
389 puts the following two restrictions on percpu variable
390 definitions.
391
392 1. percpu symbols must be unique whether static or not
393 2. percpu variables can't be defined inside a function
394
395 To ensure that generic code follows the above rules, this
396 option forces all percpu variables to be defined as weak.
397
398endmenu # "Compiler options"
399
Changbin Du6210b642019-12-06 17:03:42 -0800400menu "Generic Kernel Debugging Instruments"
401
Dave Hansen6dfc0662013-07-01 13:04:46 -0700402config MAGIC_SYSRQ
403 bool "Magic SysRq key"
404 depends on !UML
405 help
406 If you say Y here, you will have some control over the system even
407 if the system crashes for example during kernel debugging (e.g., you
408 will be able to flush the buffer cache to disk, reboot the system
409 immediately or dump some status information). This is accomplished
410 by pressing various keys while holding SysRq (Alt+PrintScreen). It
411 also works on a serial console (on PC hardware at least), if you
412 send a BREAK and then within 5 seconds a command keypress. The
Hans Holmbergf8998c22017-03-16 09:37:32 +0100413 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
414 Don't say Y unless you really know what this hack does.
Dave Hansen6dfc0662013-07-01 13:04:46 -0700415
Ben Hutchings8eaede42013-10-07 01:05:46 +0100416config MAGIC_SYSRQ_DEFAULT_ENABLE
417 hex "Enable magic SysRq key functions by default"
418 depends on MAGIC_SYSRQ
419 default 0x1
420 help
421 Specifies which SysRq key functions are enabled by default.
422 This may be set to 1 or 0 to enable or disable them all, or
Hans Holmbergf8998c22017-03-16 09:37:32 +0100423 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
Ben Hutchings8eaede42013-10-07 01:05:46 +0100424
Felix Fietkau732dbf32016-12-22 08:31:34 +0100425config MAGIC_SYSRQ_SERIAL
426 bool "Enable magic SysRq key over serial"
427 depends on MAGIC_SYSRQ
428 default y
429 help
430 Many embedded boards have a disconnected TTL level serial which can
431 generate some garbage that can lead to spurious false sysrq detects.
432 This option allows you to decide whether you want to enable the
433 magic SysRq key.
434
Dmitry Safonov68af4312020-03-02 17:51:35 +0000435config MAGIC_SYSRQ_SERIAL_SEQUENCE
436 string "Char sequence that enables magic SysRq over serial"
437 depends on MAGIC_SYSRQ_SERIAL
438 default ""
439 help
440 Specifies a sequence of characters that can follow BREAK to enable
441 SysRq on a serial console.
442
Dmitry Safonovd3394b32020-03-06 15:31:56 +0000443 If unsure, leave an empty string and the option will not be enabled.
444
Changbin Duec29a5c2019-12-06 17:04:06 -0800445config DEBUG_FS
446 bool "Debug Filesystem"
447 help
448 debugfs is a virtual file system that kernel developers use to put
449 debugging files into. Enable this option to be able to read and
450 write to these files.
451
452 For detailed documentation on the debugfs API, see
453 Documentation/filesystems/.
454
455 If unsure, say N.
456
Changbin Du6210b642019-12-06 17:03:42 -0800457source "lib/Kconfig.kgdb"
458
459source "lib/Kconfig.ubsan"
460
461endmenu
462
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800463config DEBUG_KERNEL
464 bool "Kernel debugging"
465 help
466 Say Y here if you are developing drivers or trying to debug and
467 identify kernel problems.
468
Sinan Kayac66d7a22019-05-14 15:44:00 -0700469config DEBUG_MISC
470 bool "Miscellaneous debug code"
471 default DEBUG_KERNEL
472 depends on DEBUG_KERNEL
473 help
474 Say Y here if you need to enable miscellaneous debug code that should
475 be under a more specific debug option but isn't.
476
477
Dave Hansen0610c8a2013-07-01 13:04:43 -0700478menu "Memory Debugging"
David Woodhousea304e1b2007-02-12 00:52:00 -0800479
Masahiro Yamada8636a1f2018-12-11 20:01:04 +0900480source "mm/Kconfig.debug"
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800481
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700482config DEBUG_OBJECTS
483 bool "Debug object operations"
484 depends on DEBUG_KERNEL
485 help
486 If you say Y here, additional code will be inserted into the
487 kernel to track the life time of various objects and validate
488 the operations on those objects.
489
490config DEBUG_OBJECTS_SELFTEST
491 bool "Debug objects selftest"
492 depends on DEBUG_OBJECTS
493 help
494 This enables the selftest of the object debug code.
495
496config DEBUG_OBJECTS_FREE
497 bool "Debug objects in freed memory"
498 depends on DEBUG_OBJECTS
499 help
500 This enables checks whether a k/v free operation frees an area
501 which contains an object which has not been deactivated
502 properly. This can make kmalloc/kfree-intensive workloads
503 much slower.
504
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700505config DEBUG_OBJECTS_TIMERS
506 bool "Debug timer objects"
507 depends on DEBUG_OBJECTS
508 help
509 If you say Y here, additional code will be inserted into the
510 timer routines to track the life time of timer objects and
511 validate the timer operations.
512
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900513config DEBUG_OBJECTS_WORK
514 bool "Debug work objects"
515 depends on DEBUG_OBJECTS
516 help
517 If you say Y here, additional code will be inserted into the
518 work queue routines to track the life time of work objects and
519 validate the work operations.
520
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400521config DEBUG_OBJECTS_RCU_HEAD
522 bool "Debug RCU callbacks objects"
Mathieu Desnoyersfc2ecf72011-02-23 09:42:14 -0800523 depends on DEBUG_OBJECTS
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400524 help
525 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
526
Tejun Heoe2852ae2010-10-26 14:23:05 -0700527config DEBUG_OBJECTS_PERCPU_COUNTER
528 bool "Debug percpu counter objects"
529 depends on DEBUG_OBJECTS
530 help
531 If you say Y here, additional code will be inserted into the
532 percpu counter routines to track the life time of percpu counter
533 objects and validate the percpu counter operations.
534
Ingo Molnar3ae70202008-11-26 10:02:00 +0100535config DEBUG_OBJECTS_ENABLE_DEFAULT
536 int "debug_objects bootup default value (0-1)"
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800537 range 0 1
538 default "1"
539 depends on DEBUG_OBJECTS
540 help
541 Debug objects boot parameter default value
Ingo Molnar3ae70202008-11-26 10:02:00 +0100542
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800544 bool "Debug slab memory allocations"
Levin, Alexander (Sasha Levin)4675ff02017-11-15 17:36:02 -0800545 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 help
547 Say Y here to have the kernel do limited verification on memory
548 allocation as well as poisoning memory on free to catch use of freed
549 memory. This can make kmalloc/kfree-intensive workloads much slower.
550
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700551config SLUB_DEBUG_ON
552 bool "SLUB debugging on by default"
Levin, Alexander (Sasha Levin)4675ff02017-11-15 17:36:02 -0800553 depends on SLUB && SLUB_DEBUG
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700554 default n
555 help
556 Boot with debugging on by default. SLUB boots by default with
557 the runtime debug capabilities switched off. Enabling this is
558 equivalent to specifying the "slub_debug" parameter on boot.
559 There is no support for more fine grained debug control like
560 possible with slub_debug=xxx. SLUB debugging may be switched
561 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
562 "slub_debug=-".
563
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800564config SLUB_STATS
565 default n
566 bool "Enable SLUB performance statistics"
Christoph Lameterab4d5ed2010-10-05 13:57:26 -0500567 depends on SLUB && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800568 help
569 SLUB statistics are useful to debug SLUBs allocation behavior in
570 order find ways to optimize the allocator. This should never be
571 enabled for production use since keeping statistics slows down
572 the allocator by a few percentage points. The slabinfo command
573 supports the determination of the most active slabs to figure
574 out which slabs are relevant to a particular load.
575 Try running: slabinfo -DA
576
Catalin Marinasb69ec422012-10-08 16:28:11 -0700577config HAVE_DEBUG_KMEMLEAK
578 bool
579
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100580config DEBUG_KMEMLEAK
581 bool "Kernel memory leak detector"
Kees Cook525c1f92013-01-16 18:54:16 -0800582 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
Catalin Marinas79e0d9b2011-04-27 17:06:19 +0100583 select DEBUG_FS
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100584 select STACKTRACE if STACKTRACE_SUPPORT
585 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800586 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100587 help
588 Say Y here if you want to enable the memory leak
589 detector. The memory allocation/freeing is traced in a way
590 similar to the Boehm's conservative garbage collector, the
591 difference being that the orphan objects are not freed but
592 only shown in /sys/kernel/debug/kmemleak. Enabling this
593 feature will introduce an overhead to memory
Andreas Platschek700199b02016-12-14 15:05:40 -0800594 allocations. See Documentation/dev-tools/kmemleak.rst for more
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100595 details.
596
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100597 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
598 of finding leaks due to the slab objects poisoning.
599
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100600 In order to access the kmemleak file, debugfs needs to be
601 mounted (usually at /sys/kernel/debug).
602
Catalin Marinasc5665862019-09-23 15:34:05 -0700603config DEBUG_KMEMLEAK_MEM_POOL_SIZE
604 int "Kmemleak memory pool size"
Catalin Marinasa9d90582009-06-25 10:16:11 +0100605 depends on DEBUG_KMEMLEAK
Qian Caic59180a2019-09-23 15:34:10 -0700606 range 200 1000000
Nicolas Boichatb751c522019-09-23 15:33:55 -0700607 default 16000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100608 help
609 Kmemleak must track all the memory allocations to avoid
610 reporting false positives. Since memory may be allocated or
Catalin Marinasc5665862019-09-23 15:34:05 -0700611 freed before kmemleak is fully initialised, use a static pool
612 of metadata objects to track such callbacks. After kmemleak is
613 fully initialised, this memory pool acts as an emergency one
614 if slab allocations fail.
Catalin Marinasa9d90582009-06-25 10:16:11 +0100615
Catalin Marinas0822ee42009-06-11 13:24:14 +0100616config DEBUG_KMEMLEAK_TEST
617 tristate "Simple test for the kernel memory leak detector"
Daniel Baluta97182692011-04-04 15:06:44 -0700618 depends on DEBUG_KMEMLEAK && m
Catalin Marinas0822ee42009-06-11 13:24:14 +0100619 help
Daniel Baluta97182692011-04-04 15:06:44 -0700620 This option enables a module that explicitly leaks memory.
Catalin Marinas0822ee42009-06-11 13:24:14 +0100621
622 If unsure, say N.
623
Jason Baronab0155a2010-07-19 11:54:17 +0100624config DEBUG_KMEMLEAK_DEFAULT_OFF
625 bool "Default kmemleak to off"
626 depends on DEBUG_KMEMLEAK
627 help
628 Say Y here to disable kmemleak by default. It can then be enabled
629 on the command line via kmemleak=on.
630
Sri Krishna chowdaryd53ce042018-12-28 00:38:54 -0800631config DEBUG_KMEMLEAK_AUTO_SCAN
632 bool "Enable kmemleak auto scan thread on boot up"
633 default y
634 depends on DEBUG_KMEMLEAK
635 help
636 Depending on the cpu, kmemleak scan may be cpu intensive and can
637 stall user tasks at times. This option enables/disables automatic
638 kmemleak scan at boot up.
639
640 Say N here to disable kmemleak auto scan thread to stop automatic
641 scanning. Disabling this option disables automatic reporting of
642 memory leaks.
643
644 If unsure, say Y.
645
Dave Hansen0610c8a2013-07-01 13:04:43 -0700646config DEBUG_STACK_USAGE
647 bool "Stack utilization instrumentation"
Helge Deller6c31da32016-03-19 17:54:10 +0100648 depends on DEBUG_KERNEL && !IA64
Dave Hansen0610c8a2013-07-01 13:04:43 -0700649 help
650 Enables the display of the minimum amount of free stack which each
651 task has ever had available in the sysrq-T and sysrq-P debug output.
652
653 This option will slow down process creation somewhat.
654
Changbin Dudc9b9632019-12-06 17:03:57 -0800655config SCHED_STACK_END_CHECK
656 bool "Detect stack corruption on calls to schedule()"
657 depends on DEBUG_KERNEL
658 default n
659 help
660 This option checks for a stack overrun on calls to schedule().
661 If the stack end location is found to be over written always panic as
662 the content of the corrupted region can no longer be trusted.
663 This is to ensure no erroneous behaviour occurs which could result in
664 data corruption or a sporadic crash at a later stage once the region
665 is examined. The runtime overhead introduced is minimal.
666
Dave Hansen0610c8a2013-07-01 13:04:43 -0700667config DEBUG_VM
668 bool "Debug VM"
669 depends on DEBUG_KERNEL
670 help
671 Enable this to turn on extended checks in the virtual-memory system
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800672 that may impact performance.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700673
674 If unsure, say N.
675
Davidlohr Bueso4f115142014-06-04 16:06:46 -0700676config DEBUG_VM_VMACACHE
677 bool "Debug VMA caching"
678 depends on DEBUG_VM
679 help
680 Enable this to turn on VMA caching debug information. Doing so
681 can cause significant overhead, so only enable it in non-production
682 environments.
683
684 If unsure, say N.
685
Dave Hansen0610c8a2013-07-01 13:04:43 -0700686config DEBUG_VM_RB
687 bool "Debug VM red-black trees"
688 depends on DEBUG_VM
689 help
Davidlohr Buesoa663dad2014-04-18 15:07:22 -0700690 Enable VM red-black tree debugging information and extra validations.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700691
692 If unsure, say N.
693
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800694config DEBUG_VM_PGFLAGS
695 bool "Debug page-flags operations"
696 depends on DEBUG_VM
697 help
698 Enables extra validation on page flags operations.
699
700 If unsure, say N.
701
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800702config ARCH_HAS_DEBUG_VIRTUAL
703 bool
704
Dave Hansen0610c8a2013-07-01 13:04:43 -0700705config DEBUG_VIRTUAL
706 bool "Debug VM translations"
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800707 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
Dave Hansen0610c8a2013-07-01 13:04:43 -0700708 help
709 Enable some costly sanity checks in virtual to page code. This can
710 catch mistakes with virt_to_page() and friends.
711
712 If unsure, say N.
713
714config DEBUG_NOMMU_REGIONS
715 bool "Debug the global anon/private NOMMU mapping region tree"
716 depends on DEBUG_KERNEL && !MMU
717 help
718 This option causes the global tree of anonymous and private mapping
719 regions to be regularly checked for invalid topology.
720
721config DEBUG_MEMORY_INIT
722 bool "Debug memory initialisation" if EXPERT
723 default !EXPERT
724 help
725 Enable this for additional checks during memory initialisation.
726 The sanity checks verify aspects of the VM such as the memory model
727 and other information provided by the architecture. Verbose
728 information will be printed at KERN_DEBUG loglevel depending
729 on the mminit_loglevel= command-line option.
730
731 If unsure, say Y
732
733config MEMORY_NOTIFIER_ERROR_INJECT
734 tristate "Memory hotplug notifier error injection module"
735 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
736 help
737 This option provides the ability to inject artificial errors to
738 memory hotplug notifier chain callbacks. It is controlled through
739 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
740
741 If the notifier call chain should be failed with some events
742 notified, write the error code to "actions/<notifier event>/error".
743
744 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
745
746 # cd /sys/kernel/debug/notifier-error-inject/memory
747 # echo -12 > actions/MEM_GOING_OFFLINE/error
748 # echo offline > /sys/devices/system/memory/memoryXXX/state
749 bash: echo: write error: Cannot allocate memory
750
751 To compile this code as a module, choose M here: the module will
752 be called memory-notifier-error-inject.
753
754 If unsure, say N.
755
756config DEBUG_PER_CPU_MAPS
757 bool "Debug access to per_cpu maps"
758 depends on DEBUG_KERNEL
759 depends on SMP
760 help
761 Say Y to verify that the per_cpu map being accessed has
762 been set up. This adds a fair amount of code to kernel memory
763 and decreases performance.
764
765 Say N if unsure.
766
767config DEBUG_HIGHMEM
768 bool "Highmem debugging"
769 depends on DEBUG_KERNEL && HIGHMEM
770 help
Geert Uytterhoevenb1357c92014-04-14 18:55:50 +0200771 This option enables additional error checking for high memory
772 systems. Disable for production systems.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700773
774config HAVE_DEBUG_STACKOVERFLOW
775 bool
776
777config DEBUG_STACKOVERFLOW
778 bool "Check for stack overflows"
779 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
780 ---help---
781 Say Y here if you want to check for overflows of kernel, IRQ
Borislav Petkovedb0ec02015-01-25 19:50:34 +0100782 and exception stacks (if your architecture uses them). This
Dave Hansen0610c8a2013-07-01 13:04:43 -0700783 option will show detailed messages if free stack space drops
784 below a certain limit.
785
786 These kinds of bugs usually occur when call-chains in the
787 kernel get too deep, especially when interrupts are
788 involved.
789
790 Use this in cases where you see apparently random memory
791 corruption, especially if it appears in 'struct thread_info'
792
793 If in doubt, say "N".
794
Andrey Ryabinin0b24bec2015-02-13 14:39:17 -0800795source "lib/Kconfig.kasan"
796
Dave Hansen0610c8a2013-07-01 13:04:43 -0700797endmenu # "Memory Debugging"
798
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799config DEBUG_SHIRQ
800 bool "Debug shared IRQ handlers"
Martin Schwidefsky0244ad02013-08-30 09:39:53 +0200801 depends on DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 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
Changbin Duf43a2892019-12-06 17:03:54 -0800808menu "Debug Oops, Lockups and Hangs"
809
810config PANIC_ON_OOPS
811 bool "Panic on Oops"
812 help
813 Say Y here to enable the kernel to panic when it oopses. This
814 has the same effect as setting oops=panic on the kernel command
815 line.
816
817 This feature is useful to ensure that the kernel does not do
818 anything erroneous after an oops which could result in data
819 corruption or other issues.
820
821 Say N if unsure.
822
823config PANIC_ON_OOPS_VALUE
824 int
825 range 0 1
826 default 0 if !PANIC_ON_OOPS
827 default 1 if PANIC_ON_OOPS
828
829config PANIC_TIMEOUT
830 int "panic timeout"
831 default 0
832 help
833 Set the timeout value (in seconds) until a reboot occurs when the
834 the kernel panics. If n = 0, then we wait forever. A timeout
835 value n > 0 will wait n seconds before rebooting, while a timeout
836 value n < 0 will reboot immediately.
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700837
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838config LOCKUP_DETECTOR
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700839 bool
840
841config SOFTLOCKUP_DETECTOR
842 bool "Detect Soft Lockups"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843 depends on DEBUG_KERNEL && !S390
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700844 select LOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845 help
846 Say Y here to enable the kernel to act as a watchdog to detect
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700847 soft lockups.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848
849 Softlockups are bugs that cause the kernel to loop in kernel
850 mode for more than 20 seconds, without giving other tasks a
851 chance to run. The current stack trace is displayed upon
852 detection and the system will stay locked up.
853
Randy Dunlap5f00ae02018-04-10 16:32:51 -0700854config BOOTPARAM_SOFTLOCKUP_PANIC
855 bool "Panic (Reboot) On Soft Lockups"
856 depends on SOFTLOCKUP_DETECTOR
857 help
858 Say Y here to enable the kernel to panic on "soft lockups",
859 which are bugs that cause the kernel to loop in kernel
860 mode for more than 20 seconds (configurable using the watchdog_thresh
861 sysctl), without giving other tasks a chance to run.
862
863 The panic can be used in combination with panic_timeout,
864 to cause the system to reboot automatically after a
865 lockup has been detected. This feature is useful for
866 high-availability systems that have uptime guarantees and
867 where a lockup must be resolved ASAP.
868
869 Say N if unsure.
870
871config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
872 int
873 depends on SOFTLOCKUP_DETECTOR
874 range 0 1
875 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
876 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
877
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700878config HARDLOCKUP_DETECTOR_PERF
879 bool
880 select SOFTLOCKUP_DETECTOR
881
882#
Thomas Gleixner7edaeb62017-08-15 09:50:13 +0200883# Enables a timestamp based low pass filter to compensate for perf based
884# hard lockup detection which runs too fast due to turbo modes.
885#
886config HARDLOCKUP_CHECK_TIMESTAMP
887 bool
888
889#
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700890# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
891# lockup detector rather than the perf based detector.
892#
893config HARDLOCKUP_DETECTOR
894 bool "Detect Hard Lockups"
895 depends on DEBUG_KERNEL && !S390
896 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
897 select LOCKUP_DETECTOR
898 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
899 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
900 help
901 Say Y here to enable the kernel to act as a watchdog to detect
902 hard lockups.
903
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904 Hardlockups are bugs that cause the CPU to loop in kernel mode
905 for more than 10 seconds, without letting other interrupts have a
906 chance to run. The current stack trace is displayed upon detection
907 and the system will stay locked up.
908
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909config BOOTPARAM_HARDLOCKUP_PANIC
910 bool "Panic (Reboot) On Hard Lockups"
911 depends on HARDLOCKUP_DETECTOR
912 help
913 Say Y here to enable the kernel to panic on "hard lockups",
914 which are bugs that cause the kernel to loop in kernel
915 mode with interrupts disabled for more than 10 seconds (configurable
916 using the watchdog_thresh sysctl).
917
918 Say N if unsure.
919
920config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
921 int
922 depends on HARDLOCKUP_DETECTOR
923 range 0 1
924 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
925 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
926
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927config DETECT_HUNG_TASK
928 bool "Detect Hung Tasks"
929 depends on DEBUG_KERNEL
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700930 default SOFTLOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 help
932 Say Y here to enable the kernel to detect "hung tasks",
933 which are bugs that cause the task to be stuck in
Vivien Didelot96b03ab2016-09-22 16:55:13 -0400934 uninterruptible "D" state indefinitely.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935
936 When a hung task is detected, the kernel will print the
937 current stack trace (which you should report), but the
938 task will stay in uninterruptible state. If lockdep is
939 enabled then all held locks will also be reported. This
940 feature has negligible overhead.
Al Viro871751e2006-03-25 03:06:39 -0800941
942config DEFAULT_HUNG_TASK_TIMEOUT
943 int "Default timeout for hung task detection (in seconds)"
944 depends on DETECT_HUNG_TASK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945 default 120
946 help
Ingo Molnar8637c092006-07-03 00:24:38 -0700947 This option controls the default timeout (in seconds) used
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948 to determine when a task has become non-responsive and should
949 be considered hung.
950
951 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
952 sysctl or by writing a value to
953 /proc/sys/kernel/hung_task_timeout_secs.
954
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700955 A timeout of 0 disables the check. The default is two minutes.
956 Keeping the default should be fine in most cases.
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700957
958config BOOTPARAM_HUNG_TASK_PANIC
959 bool "Panic (Reboot) On Hung Tasks"
960 depends on DETECT_HUNG_TASK
961 help
962 Say Y here to enable the kernel to panic on "hung tasks",
963 which are bugs that cause the kernel to leave a task stuck
964 in uninterruptible "D" state.
965
966 The panic can be used in combination with panic_timeout,
Thomas Gleixner61a87122006-06-27 02:54:56 -0700967 to cause the system to reboot automatically after a
968 hung task has been detected. This feature is useful for
Roman Zippela1583d32006-06-27 02:55:00 -0700969 high-availability systems that have uptime guarantees and
Thomas Gleixner61a87122006-06-27 02:54:56 -0700970 where a hung tasks must be resolved ASAP.
971
972 Say N if unsure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100974config BOOTPARAM_HUNG_TASK_PANIC_VALUE
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975 int
976 depends on DETECT_HUNG_TASK
977 range 0 1
978 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
979 default 1 if BOOTPARAM_HUNG_TASK_PANIC
980
Tejun Heo82607adc2015-12-08 11:28:04 -0500981config WQ_WATCHDOG
982 bool "Detect Workqueue Stalls"
983 depends on DEBUG_KERNEL
984 help
985 Say Y here to enable stall detection on workqueues. If a
986 worker pool doesn't make forward progress on a pending work
987 item for over a given amount of time, 30s by default, a
988 warning message is printed along with dump of workqueue
989 state. This can be configured through kernel parameter
990 "workqueue.watchdog_thresh" and its sysfs counterpart.
991
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700992endmenu # "Debug lockups and hangs"
993
Changbin Duebebdd02019-12-06 17:04:00 -0800994menu "Scheduler Debugging"
Jason Baron5800dc32013-11-25 23:23:04 +0000995
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996config SCHED_DEBUG
997 bool "Collect scheduler debugging info"
998 depends on DEBUG_KERNEL && PROC_FS
999 default y
1000 help
1001 If you say Y here, the /proc/sched_debug file will be provided
1002 that can help debug the scheduler. The runtime overhead of this
1003 option is minimal.
1004
Naveen N. Raof6db8342015-06-25 23:53:37 +05301005config SCHED_INFO
1006 bool
1007 default n
1008
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009config SCHEDSTATS
1010 bool "Collect scheduler statistics"
1011 depends on DEBUG_KERNEL && PROC_FS
Naveen N. Raof6db8342015-06-25 23:53:37 +05301012 select SCHED_INFO
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013 help
1014 If you say Y here, additional code will be inserted into the
1015 scheduler and related routines to collect statistics about
1016 scheduler behavior and provide them in /proc/schedstat. These
1017 stats may be useful for both tuning and debugging the scheduler
1018 If you aren't debugging the scheduler or trying to tune a specific
1019 application, you can say N to avoid the very slight overhead
1020 this adds.
1021
Changbin Duebebdd02019-12-06 17:04:00 -08001022endmenu
Aaron Tomlin0d9e2632014-09-12 14:16:19 +01001023
John Stultz3c17ad12015-03-11 21:16:32 -07001024config DEBUG_TIMEKEEPING
1025 bool "Enable extra timekeeping sanity checking"
1026 help
1027 This option will enable additional timekeeping sanity checks
1028 which may be helpful when diagnosing issues where timekeeping
1029 problems are suspected.
1030
1031 This may include checks in the timekeeping hotpaths, so this
1032 option may have a (very small) performance impact to some
1033 workloads.
1034
1035 If unsure, say N.
1036
Linus Torvalds1da177e2005-04-16 15:20:36 -07001037config DEBUG_PREEMPT
1038 bool "Debug preemptible kernel"
Sebastian Andrzej Siewior9f472862019-10-15 21:18:19 +02001039 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001040 default y
1041 help
1042 If you say Y here then the kernel will use a debug variant of the
1043 commonly used smp_processor_id() function and will print warnings
1044 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1045 will detect preemption count underflows.
1046
Dave Hansen9eade162013-07-01 13:04:47 -07001047menu "Lock Debugging (spinlocks, mutexes, etc...)"
1048
Waiman Longf07cbeb2018-03-30 17:27:59 -04001049config LOCK_DEBUGGING_SUPPORT
1050 bool
1051 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1052 default y
1053
Waiman Long19193bc2018-03-30 17:28:00 -04001054config PROVE_LOCKING
1055 bool "Lock debugging: prove locking correctness"
1056 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1057 select LOCKDEP
1058 select DEBUG_SPINLOCK
1059 select DEBUG_MUTEXES
1060 select DEBUG_RT_MUTEXES if RT_MUTEXES
Waiman Longc71fd892019-05-20 16:59:00 -04001061 select DEBUG_RWSEMS
Waiman Long19193bc2018-03-30 17:28:00 -04001062 select DEBUG_WW_MUTEX_SLOWPATH
1063 select DEBUG_LOCK_ALLOC
1064 select TRACE_IRQFLAGS
1065 default n
1066 help
1067 This feature enables the kernel to prove that all locking
1068 that occurs in the kernel runtime is mathematically
1069 correct: that under no circumstance could an arbitrary (and
1070 not yet triggered) combination of observed locking
1071 sequences (on an arbitrary number of CPUs, running an
1072 arbitrary number of tasks and interrupt contexts) cause a
1073 deadlock.
1074
1075 In short, this feature enables the kernel to report locking
1076 related deadlocks before they actually occur.
1077
1078 The proof does not depend on how hard and complex a
1079 deadlock scenario would be to trigger: how many
1080 participant CPUs, tasks and irq-contexts would be needed
1081 for it to trigger. The proof also does not depend on
1082 timing: if a race and a resulting deadlock is possible
1083 theoretically (no matter how unlikely the race scenario
1084 is), it will be proven so and will immediately be
1085 reported by the kernel (once the event is observed that
1086 makes the deadlock theoretically possible).
1087
1088 If a deadlock is impossible (i.e. the locking rules, as
1089 observed by the kernel, are mathematically correct), the
1090 kernel reports nothing.
1091
1092 NOTE: this feature can also be enabled for rwlocks, mutexes
1093 and rwsems - in which case all dependencies between these
1094 different locking variants are observed and mapped too, and
1095 the proof of observed correctness is also maintained for an
1096 arbitrary combination of these separate locking variants.
1097
Mauro Carvalho Chehab387b1462019-04-10 08:32:41 -03001098 For more details, see Documentation/locking/lockdep-design.rst.
Waiman Long19193bc2018-03-30 17:28:00 -04001099
Peter Zijlstrade8f5e42020-03-21 12:26:01 +01001100config PROVE_RAW_LOCK_NESTING
1101 bool "Enable raw_spinlock - spinlock nesting checks"
1102 depends on PROVE_LOCKING
1103 default n
1104 help
1105 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1106 that the lock nesting rules for PREEMPT_RT enabled kernels are
1107 not violated.
1108
1109 NOTE: There are known nesting problems. So if you enable this
1110 option expect lockdep splats until these problems have been fully
1111 addressed which is work in progress. This config switch allows to
1112 identify and analyze these problems. It will be removed and the
1113 check permanentely enabled once the main issues have been fixed.
1114
1115 If unsure, select N.
1116
Waiman Long19193bc2018-03-30 17:28:00 -04001117config LOCK_STAT
1118 bool "Lock usage statistics"
1119 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1120 select LOCKDEP
1121 select DEBUG_SPINLOCK
1122 select DEBUG_MUTEXES
1123 select DEBUG_RT_MUTEXES if RT_MUTEXES
1124 select DEBUG_LOCK_ALLOC
1125 default n
1126 help
1127 This feature enables tracking lock contention points
1128
Mauro Carvalho Chehab387b1462019-04-10 08:32:41 -03001129 For more details, see Documentation/locking/lockstat.rst
Waiman Long19193bc2018-03-30 17:28:00 -04001130
1131 This also enables lock events required by "perf lock",
1132 subcommand of perf.
1133 If you want to use "perf lock", you also need to turn on
1134 CONFIG_EVENT_TRACING.
1135
1136 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1137 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1138
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139config DEBUG_RT_MUTEXES
1140 bool "RT Mutex debugging, deadlock detection"
1141 depends on DEBUG_KERNEL && RT_MUTEXES
1142 help
1143 This allows rt mutex semantics violations and rt mutex related
1144 deadlocks (lockups) to be detected and reported automatically.
1145
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001147 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001148 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +05301149 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150 help
1151 Say Y here and build SMP to catch missing spinlock initialization
1152 and certain other kinds of spinlock errors commonly made. This is
1153 best used in conjunction with the NMI watchdog so that spinlock
1154 deadlocks are also debuggable.
1155
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001156config DEBUG_MUTEXES
1157 bool "Mutex debugging: basic checks"
1158 depends on DEBUG_KERNEL
1159 help
1160 This feature allows mutex semantics violations to be detected and
1161 reported.
1162
Daniel Vetter23010022013-06-20 13:31:17 +02001163config DEBUG_WW_MUTEX_SLOWPATH
1164 bool "Wait/wound mutex debugging: Slowpath testing"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001165 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Daniel Vetter23010022013-06-20 13:31:17 +02001166 select DEBUG_LOCK_ALLOC
1167 select DEBUG_SPINLOCK
1168 select DEBUG_MUTEXES
1169 help
1170 This feature enables slowpath testing for w/w mutex users by
1171 injecting additional -EDEADLK wound/backoff cases. Together with
1172 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1173 will test all possible w/w mutex interface abuse with the
1174 exception of simply not acquiring all the required locks.
Rob Clark4d692372014-08-27 11:19:26 -04001175 Note that this feature can introduce significant overhead, so
1176 it really should not be enabled in a production or distro kernel,
1177 even a debug kernel. If you are a driver writer, enable it. If
1178 you are a distro, do not.
Daniel Vetter23010022013-06-20 13:31:17 +02001179
Waiman Long5149cba2018-03-30 17:27:58 -04001180config DEBUG_RWSEMS
1181 bool "RW Semaphore debugging: basic checks"
Waiman Longc71fd892019-05-20 16:59:00 -04001182 depends on DEBUG_KERNEL
Waiman Long5149cba2018-03-30 17:27:58 -04001183 help
Waiman Longc71fd892019-05-20 16:59:00 -04001184 This debugging feature allows mismatched rw semaphore locks
1185 and unlocks to be detected and reported.
Waiman Long5149cba2018-03-30 17:27:58 -04001186
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001187config DEBUG_LOCK_ALLOC
1188 bool "Lock debugging: detect incorrect freeing of live locks"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001189 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001190 select DEBUG_SPINLOCK
1191 select DEBUG_MUTEXES
Peter Zijlstraf5694782016-09-19 12:15:37 +02001192 select DEBUG_RT_MUTEXES if RT_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001193 select LOCKDEP
1194 help
1195 This feature will check whether any held lock (spinlock, rwlock,
1196 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1197 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1198 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1199 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1200 held during task exit.
1201
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001202config LOCKDEP
1203 bool
Waiman Longf07cbeb2018-03-30 17:27:59 -04001204 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001205 select STACKTRACE
Stefan Agnerf9b58e82018-09-30 23:02:33 +01001206 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001207 select KALLSYMS
1208 select KALLSYMS_ALL
1209
Daniel Jordan395102d2017-04-10 11:50:52 -04001210config LOCKDEP_SMALL
1211 bool
1212
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001213config DEBUG_LOCKDEP
1214 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -07001215 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001216 help
1217 If you say Y here, the lock dependency engine will do
1218 additional runtime checks to debug itself, at the price
1219 of more runtime overhead.
1220
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001221config DEBUG_ATOMIC_SLEEP
1222 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +02001223 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224 depends on DEBUG_KERNEL
Christoph Hellwig87a4c372018-07-31 13:39:32 +02001225 depends on !ARCH_NO_PREEMPT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226 help
1227 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001228 noisy if they are called inside atomic sections: when a spinlock is
1229 held, inside an rcu read side critical section, inside preempt disabled
1230 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231
Ingo Molnarcae2ed92006-07-03 00:24:48 -07001232config DEBUG_LOCKING_API_SELFTESTS
1233 bool "Locking API boot-time self-tests"
1234 depends on DEBUG_KERNEL
1235 help
1236 Say Y here if you want the kernel to run a short self-test during
1237 bootup. The self-test checks whether common types of locking bugs
1238 are detected by debugging mechanisms or not. (if you disable
1239 lock debugging then those bugs wont be detected of course.)
1240 The following locking APIs are covered: spinlocks, rwlocks,
1241 mutexes and rwsems.
1242
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001243config LOCK_TORTURE_TEST
1244 tristate "torture tests for locking"
1245 depends on DEBUG_KERNEL
1246 select TORTURE_TEST
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001247 help
1248 This option provides a kernel module that runs torture tests
1249 on kernel locking primitives. The kernel module may be built
1250 after the fact on the running kernel to be tested, if desired.
1251
1252 Say Y here if you want kernel locking-primitive torture tests
1253 to be built into the kernel.
1254 Say M if you want these torture tests to build as a module.
1255 Say N if you are unsure.
1256
Chris Wilsonf2a5fec2016-12-01 11:47:06 +00001257config WW_MUTEX_SELFTEST
1258 tristate "Wait/wound mutex selftests"
1259 help
1260 This option provides a kernel module that runs tests on the
1261 on the struct ww_mutex locking API.
1262
1263 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1264 with this test harness.
1265
1266 Say M if you want these self tests to build as a module.
1267 Say N if you are unsure.
1268
Dave Hansen9eade162013-07-01 13:04:47 -07001269endmenu # lock debugging
1270
1271config TRACE_IRQFLAGS
1272 bool
1273 help
1274 Enables hooks to interrupt enabling and disabling for
1275 either tracing or lock debugging.
1276
Ingo Molnar8637c092006-07-03 00:24:38 -07001277config STACKTRACE
Dave Jones0c38e1f2014-08-29 15:18:35 -07001278 bool "Stack backtrace support"
Ingo Molnar8637c092006-07-03 00:24:38 -07001279 depends on STACKTRACE_SUPPORT
Dave Jones0c38e1f2014-08-29 15:18:35 -07001280 help
1281 This option causes the kernel to create a /proc/pid/stack for
1282 every process, showing its current stack trace.
1283 It is also used by various kernel debugging features that require
1284 stack trace generation.
Ingo Molnar8637c092006-07-03 00:24:38 -07001285
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001286config WARN_ALL_UNSEEDED_RANDOM
1287 bool "Warn for all uses of unseeded randomness"
1288 default n
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001289 help
1290 Some parts of the kernel contain bugs relating to their use of
1291 cryptographically secure random numbers before it's actually possible
1292 to generate those numbers securely. This setting ensures that these
1293 flaws don't go unnoticed, by enabling a message, should this ever
1294 occur. This will allow people with obscure setups to know when things
1295 are going wrong, so that they might contact developers about fixing
1296 it.
1297
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001298 Unfortunately, on some models of some architectures getting
1299 a fully seeded CRNG is extremely difficult, and so this can
1300 result in dmesg getting spammed for a surprisingly long
1301 time. This is really bad from a security perspective, and
1302 so architecture maintainers really need to do what they can
1303 to get the CRNG seeded sooner after the system is booted.
Thibaut Sautereau4c5d1142018-09-04 15:46:23 -07001304 However, since users cannot do anything actionable to
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001305 address this, by default the kernel will issue only a single
1306 warning for the first use of unseeded randomness.
1307
1308 Say Y here if you want to receive warnings for all uses of
1309 unseeded randomness. This will be of use primarily for
Thibaut Sautereau4c5d1142018-09-04 15:46:23 -07001310 those developers interested in improving the security of
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001311 Linux kernels running on their architecture (or
1312 subarchitecture).
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001313
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314config DEBUG_KOBJECT
1315 bool "kobject debugging"
1316 depends on DEBUG_KERNEL
1317 help
1318 If you say Y here, some extra kobject debugging messages will be sent
Mike Rapoportaca52c32018-10-30 15:07:44 -07001319 to the syslog.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001320
Russell Kingc817a672013-06-27 15:06:14 +01001321config DEBUG_KOBJECT_RELEASE
1322 bool "kobject release debugging"
Linus Torvalds2a999aa2013-10-29 08:33:36 -07001323 depends on DEBUG_OBJECTS_TIMERS
Russell Kingc817a672013-06-27 15:06:14 +01001324 help
1325 kobjects are reference counted objects. This means that their
1326 last reference count put is not predictable, and the kobject can
1327 live on past the point at which a driver decides to drop it's
1328 initial reference to the kobject gained on allocation. An
1329 example of this would be a struct device which has just been
1330 unregistered.
1331
1332 However, some buggy drivers assume that after such an operation,
1333 the memory backing the kobject can be immediately freed. This
1334 goes completely against the principles of a refcounted object.
1335
1336 If you say Y here, the kernel will delay the release of kobjects
1337 on the last reference count to improve the visibility of this
1338 kind of kobject release bug.
1339
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001340config HAVE_DEBUG_BUGVERBOSE
1341 bool
1342
Changbin Du3be5cbc2019-12-06 17:03:48 -08001343menu "Debug kernel data structures"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001344
Dave Jones199a9af2006-09-29 01:59:00 -07001345config DEBUG_LIST
1346 bool "Debug linked list manipulation"
Arnd Bergmann4520bcb2016-08-26 17:42:00 +02001347 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
Dave Jones199a9af2006-09-29 01:59:00 -07001348 help
1349 Enable this to turn on extended checks in the linked-list
1350 walking routines.
1351
1352 If unsure, say N.
1353
Davidlohr Bueso8e18fae2019-05-14 15:42:46 -07001354config DEBUG_PLIST
Dan Streetmanb8cfff62014-06-04 16:11:54 -07001355 bool "Debug priority linked list manipulation"
1356 depends on DEBUG_KERNEL
1357 help
1358 Enable this to turn on extended checks in the priority-ordered
1359 linked-list (plist) walking routines. This checks the entire
1360 list multiple times during each manipulation.
1361
1362 If unsure, say N.
1363
Jens Axboed6ec0842007-10-22 20:01:06 +02001364config DEBUG_SG
1365 bool "Debug SG table operations"
1366 depends on DEBUG_KERNEL
1367 help
1368 Enable this to turn on checks on scatter-gather tables. This can
1369 help find problems with drivers that do not properly initialize
1370 their sg tables.
1371
1372 If unsure, say N.
1373
Arjan van de Ven1b2439d2008-08-15 15:29:38 -07001374config DEBUG_NOTIFIERS
1375 bool "Debug notifier call chains"
1376 depends on DEBUG_KERNEL
1377 help
1378 Enable this to turn on sanity checking for notifier call chains.
1379 This is most useful for kernel developers to make sure that
1380 modules properly unregister themselves from notifier chains.
1381 This is a relatively cheap check but if you care about maximum
1382 performance, say N.
1383
Changbin Du3be5cbc2019-12-06 17:03:48 -08001384config BUG_ON_DATA_CORRUPTION
1385 bool "Trigger a BUG when data corruption is detected"
1386 select DEBUG_LIST
1387 help
1388 Select this option if the kernel should BUG when it encounters
1389 data corruption in kernel memory structures when they get checked
1390 for validity.
1391
1392 If unsure, say N.
1393
1394endmenu
1395
David Howellse0e81732009-09-02 09:13:40 +01001396config DEBUG_CREDENTIALS
1397 bool "Debug credential management"
1398 depends on DEBUG_KERNEL
1399 help
1400 Enable this to turn on some debug checking for credential
1401 management. The additional code keeps track of the number of
1402 pointers from task_structs to any given cred struct, and checks to
1403 see that this number never exceeds the usage count of the cred
1404 struct.
1405
1406 Furthermore, if SELinux is enabled, this also checks that the
1407 security pointer in the cred struct is never seen to be invalid.
1408
1409 If unsure, say N.
1410
Paul E. McKenney43a0a2a2017-05-17 09:19:44 -07001411source "kernel/rcu/Kconfig.debug"
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001412
Tejun Heof303fccb2016-02-09 17:59:38 -05001413config DEBUG_WQ_FORCE_RR_CPU
1414 bool "Force round-robin CPU selection for unbound work items"
1415 depends on DEBUG_KERNEL
1416 default n
1417 help
1418 Workqueue used to implicitly guarantee that work items queued
1419 without explicit CPU specified are put on the local CPU. This
1420 guarantee is no longer true and while local CPU is still
1421 preferred work items may be put on foreign CPUs. Kernel
1422 parameter "workqueue.debug_force_rr_cpu" is added to force
1423 round-robin CPU selection to flush out usages which depend on the
1424 now broken guarantee. This config option enables the debug
1425 feature by default. When enabled, memory and cache locality will
1426 be impacted.
1427
Tejun Heo870d6652008-08-25 19:47:25 +09001428config DEBUG_BLOCK_EXT_DEVT
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -08001429 bool "Force extended block device numbers and spread them"
Tejun Heo870d6652008-08-25 19:47:25 +09001430 depends on DEBUG_KERNEL
1431 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +02001432 default n
Tejun Heo870d6652008-08-25 19:47:25 +09001433 help
Tejun Heo0e11e342008-10-13 10:46:01 +02001434 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1435 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1436 YOU ARE DOING. Distros, please enable this and fix whatever
1437 is broken.
1438
Tejun Heo870d6652008-08-25 19:47:25 +09001439 Conventionally, block device numbers are allocated from
1440 predetermined contiguous area. However, extended block area
1441 may introduce non-contiguous block device numbers. This
1442 option forces most block device numbers to be allocated from
1443 the extended space and spreads them to discover kernel or
1444 userland code paths which assume predetermined contiguous
1445 device number allocation.
1446
Tejun Heo55dc7db2008-09-01 13:44:35 +02001447 Note that turning on this debug option shuffles all the
1448 device numbers for all IDE and SCSI devices including libata
1449 ones, so root partition specified using device number
1450 directly (via rdev or root=MAJ:MIN) won't work anymore.
1451 Textual device names (root=/dev/sdXn) will continue to work.
1452
Tejun Heo870d6652008-08-25 19:47:25 +09001453 Say N if you are unsure.
1454
Thomas Gleixner757c9892016-02-26 18:43:32 +00001455config CPU_HOTPLUG_STATE_CONTROL
1456 bool "Enable CPU hotplug state control"
1457 depends on DEBUG_KERNEL
1458 depends on HOTPLUG_CPU
1459 default n
1460 help
1461 Allows to write steps between "offline" and "online" to the CPUs
1462 sysfs target file so states can be stepped granular. This is a debug
1463 option for now as the hotplug machinery cannot be stopped and
1464 restarted at arbitrary points yet.
1465
1466 Say N if your are unsure.
1467
Changbin Du09a74952019-12-06 17:03:51 -08001468config LATENCYTOP
1469 bool "Latency measuring infrastructure"
1470 depends on DEBUG_KERNEL
1471 depends on STACKTRACE_SUPPORT
1472 depends on PROC_FS
1473 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1474 select KALLSYMS
1475 select KALLSYMS_ALL
1476 select STACKTRACE
1477 select SCHEDSTATS
1478 select SCHED_DEBUG
1479 help
1480 Enable this option if you want to use the LatencyTOP tool
1481 to find out which userspace is blocking on what kernel operations.
1482
1483source "kernel/trace/Kconfig"
1484
1485config PROVIDE_OHCI1394_DMA_INIT
1486 bool "Remote debugging over FireWire early on boot"
1487 depends on PCI && X86
1488 help
1489 If you want to debug problems which hang or crash the kernel early
1490 on boot and the crashing machine has a FireWire port, you can use
1491 this feature to remotely access the memory of the crashed machine
1492 over FireWire. This employs remote DMA as part of the OHCI1394
1493 specification which is now the standard for FireWire controllers.
1494
1495 With remote DMA, you can monitor the printk buffer remotely using
1496 firescope and access all memory below 4GB using fireproxy from gdb.
1497 Even controlling a kernel debugger is possible using remote DMA.
1498
1499 Usage:
1500
1501 If ohci1394_dma=early is used as boot parameter, it will initialize
1502 all OHCI1394 controllers which are found in the PCI config space.
1503
1504 As all changes to the FireWire bus such as enabling and disabling
1505 devices cause a bus reset and thereby disable remote DMA for all
1506 devices, be sure to have the cable plugged and FireWire enabled on
1507 the debugging host before booting the debug target for debugging.
1508
1509 This code (~1k) is freed after boot. By then, the firewire stack
1510 in charge of the OHCI-1394 controllers should be used instead.
1511
1512 See Documentation/debugging-via-ohci1394.txt for more information.
1513
Changbin Du045f6d72019-12-17 20:51:56 -08001514source "samples/Kconfig"
1515
1516config ARCH_HAS_DEVMEM_IS_ALLOWED
1517 bool
1518
1519config STRICT_DEVMEM
1520 bool "Filter access to /dev/mem"
1521 depends on MMU && DEVMEM
1522 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
1523 default y if PPC || X86 || ARM64
1524 help
1525 If this option is disabled, you allow userspace (root) access to all
1526 of memory, including kernel and userspace memory. Accidental
1527 access to this is obviously disastrous, but specific access can
1528 be used by people debugging the kernel. Note that with PAT support
1529 enabled, even in this case there are restrictions on /dev/mem
1530 use due to the cache aliasing requirements.
1531
1532 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1533 file only allows userspace access to PCI space and the BIOS code and
1534 data regions. This is sufficient for dosemu and X and all common
1535 users of /dev/mem.
1536
1537 If in doubt, say Y.
1538
1539config IO_STRICT_DEVMEM
1540 bool "Filter I/O access to /dev/mem"
1541 depends on STRICT_DEVMEM
1542 help
1543 If this option is disabled, you allow userspace (root) access to all
1544 io-memory regardless of whether a driver is actively using that
1545 range. Accidental access to this is obviously disastrous, but
1546 specific access can be used by people debugging kernel drivers.
1547
1548 If this option is switched on, the /dev/mem file only allows
1549 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1550 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1551 if the driver using a given range cannot be disabled.
1552
1553 If in doubt, say Y.
1554
1555menu "$(SRCARCH) Debugging"
1556
1557source "arch/$(SRCARCH)/Kconfig.debug"
1558
1559endmenu
1560
1561menu "Kernel Testing and Coverage"
1562
Changbin Du09a74952019-12-06 17:03:51 -08001563source "lib/kunit/Kconfig"
1564
Akinobu Mita8d438282012-07-30 14:43:02 -07001565config NOTIFIER_ERROR_INJECTION
1566 tristate "Notifier error injection"
1567 depends on DEBUG_KERNEL
1568 select DEBUG_FS
1569 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001570 This option provides the ability to inject artificial errors to
Akinobu Mita8d438282012-07-30 14:43:02 -07001571 specified notifier chain callbacks. It is useful to test the error
1572 handling of notifier call chain failures.
1573
1574 Say N if unsure.
1575
Akinobu Mita048b9c32012-07-30 14:43:07 -07001576config PM_NOTIFIER_ERROR_INJECT
1577 tristate "PM notifier error injection module"
1578 depends on PM && NOTIFIER_ERROR_INJECTION
1579 default m if PM_DEBUG
1580 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001581 This option provides the ability to inject artificial errors to
Akinobu Mita048b9c32012-07-30 14:43:07 -07001582 PM notifier chain callbacks. It is controlled through debugfs
1583 interface /sys/kernel/debug/notifier-error-inject/pm
1584
1585 If the notifier call chain should be failed with some events
1586 notified, write the error code to "actions/<notifier event>/error".
1587
1588 Example: Inject PM suspend error (-12 = -ENOMEM)
1589
1590 # cd /sys/kernel/debug/notifier-error-inject/pm/
1591 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1592 # echo mem > /sys/power/state
1593 bash: echo: write error: Cannot allocate memory
1594
1595 To compile this code as a module, choose M here: the module will
1596 be called pm-notifier-error-inject.
1597
1598 If unsure, say N.
1599
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001600config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1601 tristate "OF reconfig notifier error injection module"
1602 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001603 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001604 This option provides the ability to inject artificial errors to
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001605 OF reconfig notifier chain callbacks. It is controlled
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001606 through debugfs interface under
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001607 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001608
1609 If the notifier call chain should be failed with some events
1610 notified, write the error code to "actions/<notifier event>/error".
1611
1612 To compile this code as a module, choose M here: the module will
Akinobu Mitae12a95f2013-04-30 15:28:49 -07001613 be called of-reconfig-notifier-error-inject.
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001614
1615 If unsure, say N.
1616
Nikolay Aleksandrov02fff962015-11-28 13:45:28 +01001617config NETDEV_NOTIFIER_ERROR_INJECT
1618 tristate "Netdev notifier error injection module"
1619 depends on NET && NOTIFIER_ERROR_INJECTION
1620 help
1621 This option provides the ability to inject artificial errors to
1622 netdevice notifier chain callbacks. It is controlled through debugfs
1623 interface /sys/kernel/debug/notifier-error-inject/netdev
1624
1625 If the notifier call chain should be failed with some events
1626 notified, write the error code to "actions/<notifier event>/error".
1627
1628 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1629
1630 # cd /sys/kernel/debug/notifier-error-inject/netdev
1631 # echo -22 > actions/NETDEV_CHANGEMTU/error
1632 # ip link set eth0 mtu 1024
1633 RTNETLINK answers: Invalid argument
1634
1635 To compile this code as a module, choose M here: the module will
1636 be called netdev-notifier-error-inject.
1637
1638 If unsure, say N.
1639
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001640config FUNCTION_ERROR_INJECTION
1641 def_bool y
1642 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1643
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001644config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001645 bool "Fault-injection framework"
1646 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001647 help
1648 Provide fault-injection framework.
1649 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001650
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001651config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001652 bool "Fault-injection capability for kmalloc"
1653 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001654 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001655 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001656 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001657
Akinobu Mita933e3122006-12-08 02:39:45 -08001658config FAIL_PAGE_ALLOC
1659 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001660 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001661 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001662 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001663
Akinobu Mitac17bb492006-12-08 02:39:46 -08001664config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001665 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001666 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001667 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001668 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001669
Jens Axboe581d4e22008-09-14 05:56:33 -07001670config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d01432010-07-21 16:05:53 +09001671 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001672 depends on FAULT_INJECTION && BLOCK
1673 help
1674 Provide fault-injection capability on end IO handling. This
1675 will make the block layer "forget" an interrupt as configured,
1676 thus exercising the error handling.
1677
1678 Only works with drivers that use the generic timeout handling,
1679 for others it wont do anything.
1680
Davidlohr Buesoab51fba2015-06-29 23:26:02 -07001681config FAIL_FUTEX
1682 bool "Fault-injection capability for futexes"
1683 select DEBUG_FS
1684 depends on FAULT_INJECTION && FUTEX
1685 help
1686 Provide fault-injection capability for futexes.
1687
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001688config FAULT_INJECTION_DEBUG_FS
1689 bool "Debugfs entries for fault-injection capabilities"
1690 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1691 help
1692 Enable configuration of fault-injection capabilities via debugfs.
1693
Masami Hiramatsu4b1a29a2018-01-13 02:56:03 +09001694config FAIL_FUNCTION
1695 bool "Fault-injection capability for functions"
1696 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1697 help
1698 Provide function-based fault-injection capability.
1699 This will allow you to override a specific function with a return
1700 with given return value. As a result, function caller will see
1701 an error value and have to handle it. This is useful to test the
1702 error handling in various subsystems.
1703
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001704config FAIL_MMC_REQUEST
1705 bool "Fault-injection capability for MMC IO"
1706 depends on FAULT_INJECTION_DEBUG_FS && MMC
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001707 help
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001708 Provide fault-injection capability for MMC IO.
1709 This will make the mmc core return data errors. This is
1710 useful to test the error handling in the mmc block device
1711 and to test how the mmc host driver handles retries from
1712 the block device.
Akinobu Mita1df49002007-02-20 13:57:56 -08001713
1714config FAULT_INJECTION_STACKTRACE_FILTER
1715 bool "stacktrace filter for fault-injection capabilities"
1716 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001717 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001718 select STACKTRACE
Stefan Agnerf9b58e82018-09-30 23:02:33 +01001719 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
Akinobu Mita1df49002007-02-20 13:57:56 -08001720 help
1721 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001722
Changbin Du09a74952019-12-06 17:03:51 -08001723config ARCH_HAS_KCOV
1724 bool
Arjan van de Ven97455122008-01-25 21:08:34 +01001725 help
Changbin Du09a74952019-12-06 17:03:51 -08001726 An architecture should select this when it can successfully
1727 build and run with CONFIG_KCOV. This typically requires
1728 disabling instrumentation for some early boot code.
Arjan van de Ven97455122008-01-25 21:08:34 +01001729
Changbin Du09a74952019-12-06 17:03:51 -08001730config CC_HAS_SANCOV_TRACE_PC
1731 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001732
Changbin Du09a74952019-12-06 17:03:51 -08001733
1734config KCOV
1735 bool "Code coverage for fuzzing"
1736 depends on ARCH_HAS_KCOV
1737 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1738 select DEBUG_FS
1739 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001740 help
Changbin Du09a74952019-12-06 17:03:51 -08001741 KCOV exposes kernel code coverage information in a form suitable
1742 for coverage-guided fuzzing (randomized testing).
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001743
Changbin Du09a74952019-12-06 17:03:51 -08001744 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1745 different machines and across reboots. If you need stable PC values,
1746 disable RANDOMIZE_BASE.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001747
Changbin Du09a74952019-12-06 17:03:51 -08001748 For more details, see Documentation/dev-tools/kcov.rst.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001749
Changbin Du09a74952019-12-06 17:03:51 -08001750config KCOV_ENABLE_COMPARISONS
1751 bool "Enable comparison operands collection by KCOV"
1752 depends on KCOV
1753 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1754 help
1755 KCOV also exposes operands of every comparison in the instrumented
1756 code along with operand sizes and PCs of the comparison instructions.
1757 These operands can be used by fuzzing engines to improve the quality
1758 of fuzzing coverage.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001759
Changbin Du09a74952019-12-06 17:03:51 -08001760config KCOV_INSTRUMENT_ALL
1761 bool "Instrument all code by default"
1762 depends on KCOV
1763 default y
1764 help
1765 If you are doing generic system call fuzzing (like e.g. syzkaller),
1766 then you will want to instrument the whole kernel and you should
1767 say y here. If you are doing more targeted fuzzing (like e.g.
1768 filesystem fuzzing with AFL) then you will want to enable coverage
1769 for more specific subsets of files, and should say n here.
Brendan Higgins84bc8092019-09-23 02:02:36 -07001770
Vincent Legolld3deafa2018-02-06 15:38:38 -08001771menuconfig RUNTIME_TESTING_MENU
1772 bool "Runtime Testing"
Anders Roxell908009e82018-02-21 14:46:05 -08001773 def_bool y
Vincent Legolld3deafa2018-02-06 15:38:38 -08001774
1775if RUNTIME_TESTING_MENU
Dave Hansen881c5142013-07-01 13:04:44 -07001776
1777config LKDTM
1778 tristate "Linux Kernel Dump Test Tool Module"
1779 depends on DEBUG_FS
Dave Hansen881c5142013-07-01 13:04:44 -07001780 help
1781 This module enables testing of the different dumping mechanisms by
1782 inducing system failures at predefined crash points.
1783 If you don't need it: say N
1784 Choose M here to compile this code as a module. The module will be
1785 called lkdtm.
1786
1787 Documentation on how to use the module can be found in
Mauro Carvalho Chehab10ffebb2019-06-12 14:52:44 -03001788 Documentation/fault-injection/provoke-crashes.rst
Dave Hansen881c5142013-07-01 13:04:44 -07001789
1790config TEST_LIST_SORT
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001791 tristate "Linked list sorting test"
1792 depends on DEBUG_KERNEL || m
Dave Hansen881c5142013-07-01 13:04:44 -07001793 help
1794 Enable this to turn on 'list_sort()' function test. This test is
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001795 executed only once during system boot (so affects only boot time),
1796 or at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001797
1798 If unsure, say N.
1799
Ian Rogers6e246282020-02-13 23:51:29 -08001800config TEST_MIN_HEAP
1801 tristate "Min heap test"
1802 depends on DEBUG_KERNEL || m
1803 help
1804 Enable this to turn on min heap function tests. This test is
1805 executed only once during system boot (so affects only boot time),
1806 or at module load time.
1807
1808 If unsure, say N.
1809
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001810config TEST_SORT
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001811 tristate "Array-based sort test"
1812 depends on DEBUG_KERNEL || m
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001813 help
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001814 This option enables the self-test function of 'sort()' at boot,
1815 or at module load time.
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001816
1817 If unsure, say N.
1818
Dave Hansen881c5142013-07-01 13:04:44 -07001819config KPROBES_SANITY_TEST
1820 bool "Kprobes sanity tests"
1821 depends on DEBUG_KERNEL
1822 depends on KPROBES
Dave Hansen881c5142013-07-01 13:04:44 -07001823 help
1824 This option provides for testing basic kprobes functionality on
Masami Hiramatsu5a6cf772018-06-20 01:05:07 +09001825 boot. Samples of kprobe and kretprobe are inserted and
Dave Hansen881c5142013-07-01 13:04:44 -07001826 verified for functionality.
1827
1828 Say N if you are unsure.
1829
1830config BACKTRACE_SELF_TEST
1831 tristate "Self test for the backtrace code"
1832 depends on DEBUG_KERNEL
Dave Hansen881c5142013-07-01 13:04:44 -07001833 help
1834 This option provides a kernel module that can be used to test
1835 the kernel stack backtrace code. This option is not useful
1836 for distributions or general kernels, but only for kernel
1837 developers working on architecture code.
1838
1839 Note that if you want to also test saved backtraces, you will
1840 have to enable STACKTRACE as well.
1841
1842 Say N if you are unsure.
1843
Michel Lespinasse910a7422012-10-08 16:30:39 -07001844config RBTREE_TEST
1845 tristate "Red-Black tree test"
Cody P Schafer7c993e12013-09-11 14:25:19 -07001846 depends on DEBUG_KERNEL
Michel Lespinasse910a7422012-10-08 16:30:39 -07001847 help
1848 A benchmark measuring the performance of the rbtree library.
1849 Also includes rbtree invariant checks.
1850
Ferdinand Blomqvist4b4f3ac2019-06-20 17:10:33 +03001851config REED_SOLOMON_TEST
1852 tristate "Reed-Solomon library test"
1853 depends on DEBUG_KERNEL || m
1854 select REED_SOLOMON
1855 select REED_SOLOMON_ENC16
1856 select REED_SOLOMON_DEC16
1857 help
1858 This option enables the self-test function of rslib at boot,
1859 or at module load time.
1860
1861 If unsure, say N.
1862
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001863config INTERVAL_TREE_TEST
1864 tristate "Interval tree test"
Davidlohr Bueso0f789b62017-07-10 15:51:43 -07001865 depends on DEBUG_KERNEL
Chris Wilsona88cc102014-03-17 12:21:54 +00001866 select INTERVAL_TREE
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001867 help
1868 A benchmark measuring the performance of the interval tree library
1869
Greg Thelen623fd802013-11-12 15:08:34 -08001870config PERCPU_TEST
1871 tristate "Per cpu operations test"
1872 depends on m && DEBUG_KERNEL
1873 help
1874 Enable this option to build test module which validates per-cpu
1875 operations.
1876
1877 If unsure, say N.
1878
Dave Hansen881c5142013-07-01 13:04:44 -07001879config ATOMIC64_SELFTEST
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001880 tristate "Perform an atomic64_t self-test"
Dave Hansen881c5142013-07-01 13:04:44 -07001881 help
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001882 Enable this option to test the atomic64_t functions at boot or
1883 at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001884
1885 If unsure, say N.
1886
1887config ASYNC_RAID6_TEST
1888 tristate "Self test for hardware accelerated raid6 recovery"
1889 depends on ASYNC_RAID6_RECOV
1890 select ASYNC_MEMCPY
1891 ---help---
1892 This is a one-shot self test that permutes through the
1893 recovery of all the possible two disk failure scenarios for a
1894 N-disk array. Recovery is performed with the asynchronous
1895 raid6 recovery routines, and will optionally use an offload
1896 engine if one is available.
1897
1898 If unsure, say N.
1899
Andy Shevchenko64d1d772015-02-12 15:02:21 -08001900config TEST_HEXDUMP
1901 tristate "Test functions located in the hexdump module at runtime"
1902
Dave Hansen881c5142013-07-01 13:04:44 -07001903config TEST_STRING_HELPERS
1904 tristate "Test functions located in the string_helpers module at runtime"
1905
Tobin C. Harding0b0600c2019-04-05 12:58:59 +11001906config TEST_STRSCPY
1907 tristate "Test strscpy*() family of functions at runtime"
1908
Dave Hansen881c5142013-07-01 13:04:44 -07001909config TEST_KSTRTOX
1910 tristate "Test kstrto*() family of functions at runtime"
1911
Rasmus Villemoes707cc722015-11-06 16:30:29 -08001912config TEST_PRINTF
1913 tristate "Test printf() family of functions at runtime"
1914
David Decotigny5fd003f2016-02-19 09:24:00 -05001915config TEST_BITMAP
1916 tristate "Test bitmap_*() family of functions at runtime"
David Decotigny5fd003f2016-02-19 09:24:00 -05001917 help
1918 Enable this option to test the bitmap functions at boot.
1919
1920 If unsure, say N.
1921
Johannes Berg0e2dc702018-06-20 08:58:30 +02001922config TEST_BITFIELD
1923 tristate "Test bitfield functions at runtime"
1924 help
1925 Enable this option to test the bitfield functions at boot.
1926
1927 If unsure, say N.
1928
Andy Shevchenkocfaff0e2016-05-30 17:40:41 +03001929config TEST_UUID
1930 tristate "Test functions located in the uuid module at runtime"
1931
Matthew Wilcoxad3d6c72017-11-07 14:57:46 -05001932config TEST_XARRAY
1933 tristate "Test the XArray code at runtime"
1934
Rasmus Villemoes455a35a2018-05-08 00:36:28 +02001935config TEST_OVERFLOW
1936 tristate "Test check_*_overflow() functions at runtime"
1937
Thomas Graf7e1e7762014-08-02 11:47:44 +02001938config TEST_RHASHTABLE
Geert Uytterhoeven9d6dbe12015-01-29 15:40:25 +01001939 tristate "Perform selftest on resizable hash table"
Thomas Graf7e1e7762014-08-02 11:47:44 +02001940 help
1941 Enable this option to test the rhashtable functions at boot.
1942
1943 If unsure, say N.
1944
George Spelvin468a9422016-05-26 22:11:51 -04001945config TEST_HASH
1946 tristate "Perform selftest on hash functions"
George Spelvin468a9422016-05-26 22:11:51 -04001947 help
Jason A. Donenfeld2c956a62017-01-08 13:54:00 +01001948 Enable this option to test the kernel's integer (<linux/hash.h>),
1949 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
1950 hash functions on boot (or module load).
George Spelvin468a9422016-05-26 22:11:51 -04001951
1952 This is intended to help people writing architecture-specific
1953 optimized versions. If unsure, say N.
1954
Matthew Wilcox8ab8ba32018-06-18 16:59:29 -04001955config TEST_IDA
1956 tristate "Perform selftest on IDA functions"
1957
Jiri Pirko44091d22017-02-03 10:29:06 +01001958config TEST_PARMAN
1959 tristate "Perform selftest on priority array manager"
Jiri Pirko44091d22017-02-03 10:29:06 +01001960 depends on PARMAN
1961 help
1962 Enable this option to test priority array manager on boot
1963 (or module load).
1964
1965 If unsure, say N.
1966
Daniel Lezcano6aed82d2019-05-27 22:55:19 +02001967config TEST_IRQ_TIMINGS
1968 bool "IRQ timings selftest"
1969 depends on IRQ_TIMINGS
1970 help
1971 Enable this option to test the irq timings code on boot.
1972
1973 If unsure, say N.
1974
Valentin Rothberg8a6f0b42014-10-13 15:51:38 -07001975config TEST_LKM
Kees Cook93e9ef82014-01-23 15:54:37 -08001976 tristate "Test module loading with 'hello world' module"
Kees Cook93e9ef82014-01-23 15:54:37 -08001977 depends on m
1978 help
1979 This builds the "test_module" module that emits "Hello, world"
1980 on printk when loaded. It is designed to be used for basic
1981 evaluation of the module loading subsystem (for example when
1982 validating module verification). It lacks any extra dependencies,
1983 and will not normally be loaded by the system unless explicitly
1984 requested by name.
1985
1986 If unsure, say N.
1987
Uladzislau Rezki (Sony)3f21a6b2019-03-05 15:43:34 -08001988config TEST_VMALLOC
1989 tristate "Test module for stress/performance analysis of vmalloc allocator"
1990 default n
1991 depends on MMU
1992 depends on m
1993 help
1994 This builds the "test_vmalloc" module that should be used for
1995 stress and performance analysis. So, any new change for vmalloc
1996 subsystem can be evaluated from performance and stability point
1997 of view.
1998
1999 If unsure, say N.
2000
Kees Cook3e2a4c12014-01-23 15:54:38 -08002001config TEST_USER_COPY
2002 tristate "Test user/kernel boundary protections"
Kees Cook3e2a4c12014-01-23 15:54:38 -08002003 depends on m
2004 help
2005 This builds the "test_user_copy" module that runs sanity checks
2006 on the copy_to/from_user infrastructure, making sure basic
2007 user/kernel boundary testing is working. If it fails to load,
2008 a regression has been detected in the user/kernel memory boundary
2009 protections.
2010
2011 If unsure, say N.
2012
Alexei Starovoitov64a89462014-05-08 14:10:52 -07002013config TEST_BPF
2014 tristate "Test BPF filter functionality"
Randy Dunlap98920ba2014-05-13 09:58:44 -07002015 depends on m && NET
Alexei Starovoitov64a89462014-05-08 14:10:52 -07002016 help
2017 This builds the "test_bpf" module that runs various test vectors
2018 against the BPF interpreter or BPF JIT compiler depending on the
2019 current setting. This is in particular useful for BPF JIT compiler
2020 development, but also to run regression tests against changes in
Alexei Starovoitov3c731eb2014-09-26 00:17:07 -07002021 the interpreter code. It also enables test stubs for eBPF maps and
2022 verifier used by user space verifier testsuite.
Alexei Starovoitov64a89462014-05-08 14:10:52 -07002023
2024 If unsure, say N.
2025
Mahesh Bandewar509e56b2019-07-01 14:39:01 -07002026config TEST_BLACKHOLE_DEV
2027 tristate "Test blackhole netdev functionality"
2028 depends on m && NET
2029 help
2030 This builds the "test_blackhole_dev" module that validates the
2031 data path through this blackhole netdev.
2032
2033 If unsure, say N.
2034
Yury Norovdceeb3e2018-02-06 15:38:27 -08002035config FIND_BIT_BENCHMARK
Yury Norov4441fca2017-11-17 15:28:31 -08002036 tristate "Test find_bit functions"
Yury Norov4441fca2017-11-17 15:28:31 -08002037 help
2038 This builds the "test_find_bit" module that measure find_*_bit()
2039 functions performance.
2040
2041 If unsure, say N.
2042
Kees Cook0a8adf52014-07-14 14:38:12 -07002043config TEST_FIRMWARE
2044 tristate "Test firmware loading via userspace interface"
Kees Cook0a8adf52014-07-14 14:38:12 -07002045 depends on FW_LOADER
2046 help
2047 This builds the "test_firmware" module that creates a userspace
2048 interface for testing firmware loading. This can be used to
2049 control the triggering of firmware loading without needing an
2050 actual firmware-using device. The contents can be rechecked by
2051 userspace.
2052
2053 If unsure, say N.
2054
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07002055config TEST_SYSCTL
2056 tristate "sysctl test driver"
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07002057 depends on PROC_SYSCTL
2058 help
2059 This builds the "test_sysctl" module. This driver enables to test the
2060 proc sysctl interfaces available to drivers safely without affecting
2061 production knobs which might alter system functionality.
2062
2063 If unsure, say N.
2064
Iurii Zaikin2cb80db2019-09-23 02:02:47 -07002065config SYSCTL_KUNIT_TEST
Alan Maguirec475c772020-01-06 22:28:20 +00002066 tristate "KUnit test for sysctl"
Iurii Zaikin2cb80db2019-09-23 02:02:47 -07002067 depends on KUNIT
2068 help
2069 This builds the proc sysctl unit test, which runs on boot.
2070 Tests the API contract and implementation correctness of sysctl.
2071 For more information on KUnit and unit tests in general please refer
2072 to the KUnit documentation in Documentation/dev-tools/kunit/.
2073
2074 If unsure, say N.
2075
David Gowea2dd7c2019-10-24 15:46:31 -07002076config LIST_KUNIT_TEST
Alan Maguirec475c772020-01-06 22:28:20 +00002077 tristate "KUnit Test for Kernel Linked-list structures"
David Gowea2dd7c2019-10-24 15:46:31 -07002078 depends on KUNIT
2079 help
2080 This builds the linked list KUnit test suite.
2081 It tests that the API and basic functionality of the list_head type
2082 and associated macros.
2083
2084 KUnit tests run during boot and output the results to the debug log
2085 in TAP format (http://testanything.org/). Only useful for kernel devs
2086 running the KUnit test harness, and not intended for inclusion into a
2087 production build.
2088
2089 For more information on KUnit and unit tests in general please refer
2090 to the KUnit documentation in Documentation/dev-tools/kunit/.
2091
2092 If unsure, say N.
2093
David Rileye704f932014-06-16 14:58:32 -07002094config TEST_UDELAY
2095 tristate "udelay test driver"
David Rileye704f932014-06-16 14:58:32 -07002096 help
2097 This builds the "udelay_test" module that helps to make sure
2098 that udelay() is working properly.
2099
2100 If unsure, say N.
2101
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02002102config TEST_STATIC_KEYS
2103 tristate "Test static keys"
Jason Baron579e1ac2015-07-30 03:59:44 +00002104 depends on m
2105 help
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02002106 Test the static key interfaces.
Jason Baron579e1ac2015-07-30 03:59:44 +00002107
2108 If unsure, say N.
2109
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002110config TEST_KMOD
2111 tristate "kmod stress tester"
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002112 depends on m
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002113 depends on NETDEVICES && NET_CORE && INET # for TUN
YueHaibingae3d6a32019-04-25 22:23:44 -07002114 depends on BLOCK
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002115 select TEST_LKM
2116 select XFS_FS
2117 select TUN
2118 select BTRFS_FS
2119 help
2120 Test the kernel's module loading mechanism: kmod. kmod implements
2121 support to load modules using the Linux kernel's usermode helper.
2122 This test provides a series of tests against kmod.
2123
2124 Although technically you can either build test_kmod as a module or
2125 into the kernel we disallow building it into the kernel since
2126 it stress tests request_module() and this will very likely cause
2127 some issues by taking over precious threads available from other
2128 module load requests, ultimately this could be fatal.
2129
2130 To run tests run:
2131
2132 tools/testing/selftests/kmod/kmod.sh --help
2133
2134 If unsure, say N.
2135
Florian Fainellie4dace32017-09-08 16:15:31 -07002136config TEST_DEBUG_VIRTUAL
2137 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2138 depends on DEBUG_VIRTUAL
2139 help
2140 Test the kernel's ability to detect incorrect calls to
2141 virt_to_phys() done against the non-linear part of the
2142 kernel's virtual address map.
2143
2144 If unsure, say N.
2145
Alexander Shishkince76d932018-10-05 15:43:05 +03002146config TEST_MEMCAT_P
2147 tristate "Test memcat_p() helper function"
2148 help
2149 Test the memcat_p() helper for correctly merging two
2150 pointer arrays together.
2151
2152 If unsure, say N.
2153
Joe Lawrencea2818ee2019-01-09 13:43:29 +01002154config TEST_LIVEPATCH
2155 tristate "Test livepatching"
2156 default n
Joe Lawrencebae05432019-01-31 11:41:24 -05002157 depends on DYNAMIC_DEBUG
Joe Lawrencea2818ee2019-01-09 13:43:29 +01002158 depends on LIVEPATCH
2159 depends on m
2160 help
2161 Test kernel livepatching features for correctness. The tests will
2162 load test modules that will be livepatched in various scenarios.
2163
2164 To run all the livepatching tests:
2165
2166 make -C tools/testing/selftests TARGETS=livepatch run_tests
2167
2168 Alternatively, individual tests may be invoked:
2169
2170 tools/testing/selftests/livepatch/test-callbacks.sh
2171 tools/testing/selftests/livepatch/test-livepatch.sh
2172 tools/testing/selftests/livepatch/test-shadow-vars.sh
2173
2174 If unsure, say N.
2175
Jiri Pirko0a020d42018-11-14 08:22:28 +00002176config TEST_OBJAGG
2177 tristate "Perform selftest on object aggreration manager"
2178 default n
2179 depends on OBJAGG
2180 help
2181 Enable this option to test object aggregation manager on boot
2182 (or module load).
2183
Jiri Pirko0a020d42018-11-14 08:22:28 +00002184
Kees Cook50ceaa95e2019-01-23 12:24:32 -07002185config TEST_STACKINIT
2186 tristate "Test level of stack variable initialization"
2187 help
2188 Test if the kernel is zero-initializing stack variables and
2189 padding. Coverage is controlled by compiler flags,
2190 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2191 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2192
2193 If unsure, say N.
2194
Alexander Potapenko5015a302019-07-16 16:27:27 -07002195config TEST_MEMINIT
2196 tristate "Test heap/page initialization"
2197 help
2198 Test if the kernel is zero-initializing heap and page allocations.
2199 This can be useful to test init_on_alloc and init_on_free features.
2200
2201 If unsure, say N.
2202
Vincent Legolld3deafa2018-02-06 15:38:38 -08002203endif # RUNTIME_TESTING_MENU
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002204
2205config MEMTEST
2206 bool "Memtest"
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002207 ---help---
2208 This option adds a kernel parameter 'memtest', which allows memtest
2209 to be set.
2210 memtest=0, mean disabled; -- default
2211 memtest=1, mean do 1 test pattern;
2212 ...
2213 memtest=17, mean do 17 test patterns.
2214 If you are unsure how to answer this question, answer N.
2215
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002216
Christoph Hellwig06ec64b2018-07-31 13:39:31 +02002217
Branden Bonabyaf9ca6f2019-10-03 17:01:49 -04002218config HYPERV_TESTING
2219 bool "Microsoft Hyper-V driver testing"
2220 default n
2221 depends on HYPERV && DEBUG_FS
2222 help
2223 Select this option to enable Hyper-V vmbus testing.
2224
Changbin Du045f6d72019-12-17 20:51:56 -08002225endmenu # "Kernel Testing and Coverage"
2226
Christoph Hellwig06ec64b2018-07-31 13:39:31 +02002227endmenu # Kernel hacking