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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
244 help
245 Generate deduplicated BTF type information from DWARF debug info.
246 Turning this on expects presence of pahole tool, which will convert
247 DWARF type info into equivalent deduplicated BTF type info.
248
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800249config GDB_SCRIPTS
250 bool "Provide GDB scripts for kernel debugging"
251 depends on DEBUG_INFO
252 help
253 This creates the required links to GDB helper scripts in the
254 build directory. If you load vmlinux into gdb, the helper
255 scripts will be automatically imported by gdb as well, and
256 additional functions are available to analyze a Linux kernel
Andreas Platschek700199b02016-12-14 15:05:40 -0800257 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
258 for further details.
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800259
Andrew Mortoncebc04b2006-08-14 22:43:18 -0700260config ENABLE_MUST_CHECK
261 bool "Enable __must_check logic"
262 default y
263 help
264 Enable the __must_check logic in the kernel build. Disable this to
265 suppress the "warning: ignoring return value of 'foo', declared with
266 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267
Andi Kleen35bb5b12008-02-22 15:15:03 +0100268config FRAME_WARN
Masahiro Yamadaa83e4ca2020-02-17 00:19:36 +0900269 int "Warn for stack frames larger than"
Andi Kleen35bb5b12008-02-22 15:15:03 +0100270 range 0 8192
Kees Cook0e07f662016-10-27 17:46:41 -0700271 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
Helge Deller432654d2017-09-11 21:41:43 +0200272 default 1280 if (!64BIT && PARISC)
273 default 1024 if (!64BIT && !PARISC)
Andi Kleen35bb5b12008-02-22 15:15:03 +0100274 default 2048 if 64BIT
275 help
276 Tell gcc to warn at build time for stack frames larger than this.
277 Setting this too low will cause a lot of warnings.
278 Setting it to 0 disables the warning.
Andi Kleen35bb5b12008-02-22 15:15:03 +0100279
Randy Dunlap99657c72009-09-18 12:49:22 -0700280config STRIP_ASM_SYMS
281 bool "Strip assembler-generated symbols during link"
282 default n
283 help
284 Strip internal assembler-generated symbols during a link (symbols
285 that look like '.Lxxx') so they don't pollute the output of
286 get_wchan() and suchlike.
287
Andi Kleen1873e872012-03-28 11:51:18 -0700288config READABLE_ASM
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800289 bool "Generate readable assembler code"
290 depends on DEBUG_KERNEL
Don Mullisbf4735a2006-12-10 02:18:37 -0800291 help
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800292 Disable some compiler optimizations that tend to generate human unreadable
293 assembler output. This may make the kernel slightly slower, but it helps
294 to keep kernel developers who have to stare a lot at assembler listings
295 sane.
Don Mullisbf4735a2006-12-10 02:18:37 -0800296
Masahiro Yamadae949f4c2019-06-04 19:13:59 +0900297config HEADERS_INSTALL
298 bool "Install uapi headers to usr/include"
Don Mullisbf4735a2006-12-10 02:18:37 -0800299 depends on !UML
300 help
Masahiro Yamadae949f4c2019-06-04 19:13:59 +0900301 This option will install uapi headers (headers exported to user-space)
302 into the usr/include directory for use during the kernel build.
303 This is unneeded for building the kernel itself, but needed for some
304 user-space program samples. It is also needed by some features such
305 as uapi header sanity checks.
306
Masahiro Yamada9012d012019-05-14 15:42:25 -0700307config OPTIMIZE_INLINING
Masahiro Yamadaac7c3e42019-09-25 16:47:42 -0700308 def_bool y
Masahiro Yamada9012d012019-05-14 15:42:25 -0700309 help
310 This option determines if the kernel forces gcc to inline the functions
311 developers have marked 'inline'. Doing so takes away freedom from gcc to
312 do what it thinks is best, which is desirable for the gcc 3.x series of
313 compilers. The gcc 4.x series have a rewritten inlining algorithm and
314 enabling this option will generate a smaller kernel there. Hopefully
315 this algorithm is so good that allowing gcc 4.x and above to make the
316 decision will become the default in the future. Until then this option
317 is there to test gcc for this.
318
Sam Ravnborg91341d42008-01-21 21:31:44 +0100319config DEBUG_SECTION_MISMATCH
320 bool "Enable full Section mismatch analysis"
Sam Ravnborg91341d42008-01-21 21:31:44 +0100321 help
322 The section mismatch analysis checks if there are illegal
323 references from one section to another section.
Michael Wittene809ab02011-04-17 04:08:48 +0000324 During linktime or runtime, some sections are dropped;
325 any use of code/data previously in these sections would
Sam Ravnborg91341d42008-01-21 21:31:44 +0100326 most likely result in an oops.
Michael Wittene809ab02011-04-17 04:08:48 +0000327 In the code, functions and variables are annotated with
Paul Gortmaker0db06282013-06-19 14:53:51 -0400328 __init,, etc. (see the full list in include/linux/init.h),
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100329 which results in the code/data being placed in specific sections.
Michael Wittene809ab02011-04-17 04:08:48 +0000330 The section mismatch analysis is always performed after a full
331 kernel build, and enabling this option causes the following
Masahiro Yamadab7dca6d2019-07-17 15:17:57 +0900332 additional step to occur:
Michael Wittene809ab02011-04-17 04:08:48 +0000333 - Add the option -fno-inline-functions-called-once to gcc commands.
334 When inlining a function annotated with __init in a non-init
335 function, we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100336 the analysis would not catch the illegal reference.
Michael Wittene809ab02011-04-17 04:08:48 +0000337 This option tells gcc to inline less (but it does result in
338 a larger kernel).
Sam Ravnborg91341d42008-01-21 21:31:44 +0100339
Nicolas Boichat47490ec2015-10-06 09:44:42 +1030340config SECTION_MISMATCH_WARN_ONLY
341 bool "Make section mismatch errors non-fatal"
342 default y
343 help
344 If you say N here, the build process will fail if there are any
345 section mismatch, instead of just throwing warnings.
346
347 If unsure, say Y.
348
Dave Hansen6dfc0662013-07-01 13:04:46 -0700349#
350# Select this config option from the architecture Kconfig, if it
351# is preferred to always offer frame pointers as a config
352# option on the architecture (regardless of KERNEL_DEBUG):
353#
354config ARCH_WANT_FRAME_POINTERS
355 bool
Dave Hansen6dfc0662013-07-01 13:04:46 -0700356
357config FRAME_POINTER
358 bool "Compile the kernel with frame pointers"
Arnd Bergmanna687a532018-03-07 23:30:54 +0100359 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
Dave Hansen6dfc0662013-07-01 13:04:46 -0700360 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
361 help
362 If you say Y here the resulting kernel image will be slightly
363 larger and slower, but it gives very useful debugging information
364 in case of kernel bugs. (precise oopses/stacktraces/warnings)
365
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600366config STACK_VALIDATION
367 bool "Compile-time stack metadata validation"
368 depends on HAVE_STACK_VALIDATION
369 default n
370 help
371 Add compile-time checks to validate stack metadata, including frame
372 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
373 that runtime stack traces are more reliable.
374
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500375 This is also a prerequisite for generation of ORC unwind data, which
Josh Poimboeuf11af8472017-10-13 15:02:00 -0500376 is needed for CONFIG_UNWINDER_ORC.
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500377
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600378 For more information, see
379 tools/objtool/Documentation/stack-validation.txt.
380
Dave Hansen6dfc0662013-07-01 13:04:46 -0700381config DEBUG_FORCE_WEAK_PER_CPU
382 bool "Force weak per-cpu definitions"
383 depends on DEBUG_KERNEL
384 help
385 s390 and alpha require percpu variables in modules to be
386 defined weak to work around addressing range issue which
387 puts the following two restrictions on percpu variable
388 definitions.
389
390 1. percpu symbols must be unique whether static or not
391 2. percpu variables can't be defined inside a function
392
393 To ensure that generic code follows the above rules, this
394 option forces all percpu variables to be defined as weak.
395
396endmenu # "Compiler options"
397
Changbin Du6210b642019-12-06 17:03:42 -0800398menu "Generic Kernel Debugging Instruments"
399
Dave Hansen6dfc0662013-07-01 13:04:46 -0700400config MAGIC_SYSRQ
401 bool "Magic SysRq key"
402 depends on !UML
403 help
404 If you say Y here, you will have some control over the system even
405 if the system crashes for example during kernel debugging (e.g., you
406 will be able to flush the buffer cache to disk, reboot the system
407 immediately or dump some status information). This is accomplished
408 by pressing various keys while holding SysRq (Alt+PrintScreen). It
409 also works on a serial console (on PC hardware at least), if you
410 send a BREAK and then within 5 seconds a command keypress. The
Hans Holmbergf8998c22017-03-16 09:37:32 +0100411 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
412 Don't say Y unless you really know what this hack does.
Dave Hansen6dfc0662013-07-01 13:04:46 -0700413
Ben Hutchings8eaede42013-10-07 01:05:46 +0100414config MAGIC_SYSRQ_DEFAULT_ENABLE
415 hex "Enable magic SysRq key functions by default"
416 depends on MAGIC_SYSRQ
417 default 0x1
418 help
419 Specifies which SysRq key functions are enabled by default.
420 This may be set to 1 or 0 to enable or disable them all, or
Hans Holmbergf8998c22017-03-16 09:37:32 +0100421 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
Ben Hutchings8eaede42013-10-07 01:05:46 +0100422
Felix Fietkau732dbf32016-12-22 08:31:34 +0100423config MAGIC_SYSRQ_SERIAL
424 bool "Enable magic SysRq key over serial"
425 depends on MAGIC_SYSRQ
426 default y
427 help
428 Many embedded boards have a disconnected TTL level serial which can
429 generate some garbage that can lead to spurious false sysrq detects.
430 This option allows you to decide whether you want to enable the
431 magic SysRq key.
432
Dmitry Safonov68af4312020-03-02 17:51:35 +0000433config MAGIC_SYSRQ_SERIAL_SEQUENCE
434 string "Char sequence that enables magic SysRq over serial"
435 depends on MAGIC_SYSRQ_SERIAL
436 default ""
437 help
438 Specifies a sequence of characters that can follow BREAK to enable
439 SysRq on a serial console.
440
Dmitry Safonovd3394b32020-03-06 15:31:56 +0000441 If unsure, leave an empty string and the option will not be enabled.
442
Changbin Duec29a5c2019-12-06 17:04:06 -0800443config DEBUG_FS
444 bool "Debug Filesystem"
445 help
446 debugfs is a virtual file system that kernel developers use to put
447 debugging files into. Enable this option to be able to read and
448 write to these files.
449
450 For detailed documentation on the debugfs API, see
451 Documentation/filesystems/.
452
453 If unsure, say N.
454
Changbin Du6210b642019-12-06 17:03:42 -0800455source "lib/Kconfig.kgdb"
456
457source "lib/Kconfig.ubsan"
458
459endmenu
460
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800461config DEBUG_KERNEL
462 bool "Kernel debugging"
463 help
464 Say Y here if you are developing drivers or trying to debug and
465 identify kernel problems.
466
Sinan Kayac66d7a22019-05-14 15:44:00 -0700467config DEBUG_MISC
468 bool "Miscellaneous debug code"
469 default DEBUG_KERNEL
470 depends on DEBUG_KERNEL
471 help
472 Say Y here if you need to enable miscellaneous debug code that should
473 be under a more specific debug option but isn't.
474
475
Dave Hansen0610c8a2013-07-01 13:04:43 -0700476menu "Memory Debugging"
David Woodhousea304e1b2007-02-12 00:52:00 -0800477
Masahiro Yamada8636a1f2018-12-11 20:01:04 +0900478source "mm/Kconfig.debug"
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800479
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700480config DEBUG_OBJECTS
481 bool "Debug object operations"
482 depends on DEBUG_KERNEL
483 help
484 If you say Y here, additional code will be inserted into the
485 kernel to track the life time of various objects and validate
486 the operations on those objects.
487
488config DEBUG_OBJECTS_SELFTEST
489 bool "Debug objects selftest"
490 depends on DEBUG_OBJECTS
491 help
492 This enables the selftest of the object debug code.
493
494config DEBUG_OBJECTS_FREE
495 bool "Debug objects in freed memory"
496 depends on DEBUG_OBJECTS
497 help
498 This enables checks whether a k/v free operation frees an area
499 which contains an object which has not been deactivated
500 properly. This can make kmalloc/kfree-intensive workloads
501 much slower.
502
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700503config DEBUG_OBJECTS_TIMERS
504 bool "Debug timer objects"
505 depends on DEBUG_OBJECTS
506 help
507 If you say Y here, additional code will be inserted into the
508 timer routines to track the life time of timer objects and
509 validate the timer operations.
510
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900511config DEBUG_OBJECTS_WORK
512 bool "Debug work objects"
513 depends on DEBUG_OBJECTS
514 help
515 If you say Y here, additional code will be inserted into the
516 work queue routines to track the life time of work objects and
517 validate the work operations.
518
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400519config DEBUG_OBJECTS_RCU_HEAD
520 bool "Debug RCU callbacks objects"
Mathieu Desnoyersfc2ecf72011-02-23 09:42:14 -0800521 depends on DEBUG_OBJECTS
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400522 help
523 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
524
Tejun Heoe2852ae2010-10-26 14:23:05 -0700525config DEBUG_OBJECTS_PERCPU_COUNTER
526 bool "Debug percpu counter objects"
527 depends on DEBUG_OBJECTS
528 help
529 If you say Y here, additional code will be inserted into the
530 percpu counter routines to track the life time of percpu counter
531 objects and validate the percpu counter operations.
532
Ingo Molnar3ae70202008-11-26 10:02:00 +0100533config DEBUG_OBJECTS_ENABLE_DEFAULT
534 int "debug_objects bootup default value (0-1)"
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800535 range 0 1
536 default "1"
537 depends on DEBUG_OBJECTS
538 help
539 Debug objects boot parameter default value
Ingo Molnar3ae70202008-11-26 10:02:00 +0100540
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800542 bool "Debug slab memory allocations"
Levin, Alexander (Sasha Levin)4675ff02017-11-15 17:36:02 -0800543 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 help
545 Say Y here to have the kernel do limited verification on memory
546 allocation as well as poisoning memory on free to catch use of freed
547 memory. This can make kmalloc/kfree-intensive workloads much slower.
548
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700549config SLUB_DEBUG_ON
550 bool "SLUB debugging on by default"
Levin, Alexander (Sasha Levin)4675ff02017-11-15 17:36:02 -0800551 depends on SLUB && SLUB_DEBUG
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700552 default n
553 help
554 Boot with debugging on by default. SLUB boots by default with
555 the runtime debug capabilities switched off. Enabling this is
556 equivalent to specifying the "slub_debug" parameter on boot.
557 There is no support for more fine grained debug control like
558 possible with slub_debug=xxx. SLUB debugging may be switched
559 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
560 "slub_debug=-".
561
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800562config SLUB_STATS
563 default n
564 bool "Enable SLUB performance statistics"
Christoph Lameterab4d5ed2010-10-05 13:57:26 -0500565 depends on SLUB && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800566 help
567 SLUB statistics are useful to debug SLUBs allocation behavior in
568 order find ways to optimize the allocator. This should never be
569 enabled for production use since keeping statistics slows down
570 the allocator by a few percentage points. The slabinfo command
571 supports the determination of the most active slabs to figure
572 out which slabs are relevant to a particular load.
573 Try running: slabinfo -DA
574
Catalin Marinasb69ec422012-10-08 16:28:11 -0700575config HAVE_DEBUG_KMEMLEAK
576 bool
577
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100578config DEBUG_KMEMLEAK
579 bool "Kernel memory leak detector"
Kees Cook525c1f92013-01-16 18:54:16 -0800580 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
Catalin Marinas79e0d9b2011-04-27 17:06:19 +0100581 select DEBUG_FS
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100582 select STACKTRACE if STACKTRACE_SUPPORT
583 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800584 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100585 help
586 Say Y here if you want to enable the memory leak
587 detector. The memory allocation/freeing is traced in a way
588 similar to the Boehm's conservative garbage collector, the
589 difference being that the orphan objects are not freed but
590 only shown in /sys/kernel/debug/kmemleak. Enabling this
591 feature will introduce an overhead to memory
Andreas Platschek700199b02016-12-14 15:05:40 -0800592 allocations. See Documentation/dev-tools/kmemleak.rst for more
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100593 details.
594
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100595 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
596 of finding leaks due to the slab objects poisoning.
597
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100598 In order to access the kmemleak file, debugfs needs to be
599 mounted (usually at /sys/kernel/debug).
600
Catalin Marinasc5665862019-09-23 15:34:05 -0700601config DEBUG_KMEMLEAK_MEM_POOL_SIZE
602 int "Kmemleak memory pool size"
Catalin Marinasa9d90582009-06-25 10:16:11 +0100603 depends on DEBUG_KMEMLEAK
Qian Caic59180a2019-09-23 15:34:10 -0700604 range 200 1000000
Nicolas Boichatb751c522019-09-23 15:33:55 -0700605 default 16000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100606 help
607 Kmemleak must track all the memory allocations to avoid
608 reporting false positives. Since memory may be allocated or
Catalin Marinasc5665862019-09-23 15:34:05 -0700609 freed before kmemleak is fully initialised, use a static pool
610 of metadata objects to track such callbacks. After kmemleak is
611 fully initialised, this memory pool acts as an emergency one
612 if slab allocations fail.
Catalin Marinasa9d90582009-06-25 10:16:11 +0100613
Catalin Marinas0822ee42009-06-11 13:24:14 +0100614config DEBUG_KMEMLEAK_TEST
615 tristate "Simple test for the kernel memory leak detector"
Daniel Baluta97182692011-04-04 15:06:44 -0700616 depends on DEBUG_KMEMLEAK && m
Catalin Marinas0822ee42009-06-11 13:24:14 +0100617 help
Daniel Baluta97182692011-04-04 15:06:44 -0700618 This option enables a module that explicitly leaks memory.
Catalin Marinas0822ee42009-06-11 13:24:14 +0100619
620 If unsure, say N.
621
Jason Baronab0155a2010-07-19 11:54:17 +0100622config DEBUG_KMEMLEAK_DEFAULT_OFF
623 bool "Default kmemleak to off"
624 depends on DEBUG_KMEMLEAK
625 help
626 Say Y here to disable kmemleak by default. It can then be enabled
627 on the command line via kmemleak=on.
628
Sri Krishna chowdaryd53ce042018-12-28 00:38:54 -0800629config DEBUG_KMEMLEAK_AUTO_SCAN
630 bool "Enable kmemleak auto scan thread on boot up"
631 default y
632 depends on DEBUG_KMEMLEAK
633 help
634 Depending on the cpu, kmemleak scan may be cpu intensive and can
635 stall user tasks at times. This option enables/disables automatic
636 kmemleak scan at boot up.
637
638 Say N here to disable kmemleak auto scan thread to stop automatic
639 scanning. Disabling this option disables automatic reporting of
640 memory leaks.
641
642 If unsure, say Y.
643
Dave Hansen0610c8a2013-07-01 13:04:43 -0700644config DEBUG_STACK_USAGE
645 bool "Stack utilization instrumentation"
Helge Deller6c31da32016-03-19 17:54:10 +0100646 depends on DEBUG_KERNEL && !IA64
Dave Hansen0610c8a2013-07-01 13:04:43 -0700647 help
648 Enables the display of the minimum amount of free stack which each
649 task has ever had available in the sysrq-T and sysrq-P debug output.
650
651 This option will slow down process creation somewhat.
652
Changbin Dudc9b9632019-12-06 17:03:57 -0800653config SCHED_STACK_END_CHECK
654 bool "Detect stack corruption on calls to schedule()"
655 depends on DEBUG_KERNEL
656 default n
657 help
658 This option checks for a stack overrun on calls to schedule().
659 If the stack end location is found to be over written always panic as
660 the content of the corrupted region can no longer be trusted.
661 This is to ensure no erroneous behaviour occurs which could result in
662 data corruption or a sporadic crash at a later stage once the region
663 is examined. The runtime overhead introduced is minimal.
664
Dave Hansen0610c8a2013-07-01 13:04:43 -0700665config DEBUG_VM
666 bool "Debug VM"
667 depends on DEBUG_KERNEL
668 help
669 Enable this to turn on extended checks in the virtual-memory system
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800670 that may impact performance.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700671
672 If unsure, say N.
673
Davidlohr Bueso4f115142014-06-04 16:06:46 -0700674config DEBUG_VM_VMACACHE
675 bool "Debug VMA caching"
676 depends on DEBUG_VM
677 help
678 Enable this to turn on VMA caching debug information. Doing so
679 can cause significant overhead, so only enable it in non-production
680 environments.
681
682 If unsure, say N.
683
Dave Hansen0610c8a2013-07-01 13:04:43 -0700684config DEBUG_VM_RB
685 bool "Debug VM red-black trees"
686 depends on DEBUG_VM
687 help
Davidlohr Buesoa663dad2014-04-18 15:07:22 -0700688 Enable VM red-black tree debugging information and extra validations.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700689
690 If unsure, say N.
691
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800692config DEBUG_VM_PGFLAGS
693 bool "Debug page-flags operations"
694 depends on DEBUG_VM
695 help
696 Enables extra validation on page flags operations.
697
698 If unsure, say N.
699
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800700config ARCH_HAS_DEBUG_VIRTUAL
701 bool
702
Dave Hansen0610c8a2013-07-01 13:04:43 -0700703config DEBUG_VIRTUAL
704 bool "Debug VM translations"
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800705 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
Dave Hansen0610c8a2013-07-01 13:04:43 -0700706 help
707 Enable some costly sanity checks in virtual to page code. This can
708 catch mistakes with virt_to_page() and friends.
709
710 If unsure, say N.
711
712config DEBUG_NOMMU_REGIONS
713 bool "Debug the global anon/private NOMMU mapping region tree"
714 depends on DEBUG_KERNEL && !MMU
715 help
716 This option causes the global tree of anonymous and private mapping
717 regions to be regularly checked for invalid topology.
718
719config DEBUG_MEMORY_INIT
720 bool "Debug memory initialisation" if EXPERT
721 default !EXPERT
722 help
723 Enable this for additional checks during memory initialisation.
724 The sanity checks verify aspects of the VM such as the memory model
725 and other information provided by the architecture. Verbose
726 information will be printed at KERN_DEBUG loglevel depending
727 on the mminit_loglevel= command-line option.
728
729 If unsure, say Y
730
731config MEMORY_NOTIFIER_ERROR_INJECT
732 tristate "Memory hotplug notifier error injection module"
733 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
734 help
735 This option provides the ability to inject artificial errors to
736 memory hotplug notifier chain callbacks. It is controlled through
737 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
738
739 If the notifier call chain should be failed with some events
740 notified, write the error code to "actions/<notifier event>/error".
741
742 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
743
744 # cd /sys/kernel/debug/notifier-error-inject/memory
745 # echo -12 > actions/MEM_GOING_OFFLINE/error
746 # echo offline > /sys/devices/system/memory/memoryXXX/state
747 bash: echo: write error: Cannot allocate memory
748
749 To compile this code as a module, choose M here: the module will
750 be called memory-notifier-error-inject.
751
752 If unsure, say N.
753
754config DEBUG_PER_CPU_MAPS
755 bool "Debug access to per_cpu maps"
756 depends on DEBUG_KERNEL
757 depends on SMP
758 help
759 Say Y to verify that the per_cpu map being accessed has
760 been set up. This adds a fair amount of code to kernel memory
761 and decreases performance.
762
763 Say N if unsure.
764
765config DEBUG_HIGHMEM
766 bool "Highmem debugging"
767 depends on DEBUG_KERNEL && HIGHMEM
768 help
Geert Uytterhoevenb1357c92014-04-14 18:55:50 +0200769 This option enables additional error checking for high memory
770 systems. Disable for production systems.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700771
772config HAVE_DEBUG_STACKOVERFLOW
773 bool
774
775config DEBUG_STACKOVERFLOW
776 bool "Check for stack overflows"
777 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
778 ---help---
779 Say Y here if you want to check for overflows of kernel, IRQ
Borislav Petkovedb0ec02015-01-25 19:50:34 +0100780 and exception stacks (if your architecture uses them). This
Dave Hansen0610c8a2013-07-01 13:04:43 -0700781 option will show detailed messages if free stack space drops
782 below a certain limit.
783
784 These kinds of bugs usually occur when call-chains in the
785 kernel get too deep, especially when interrupts are
786 involved.
787
788 Use this in cases where you see apparently random memory
789 corruption, especially if it appears in 'struct thread_info'
790
791 If in doubt, say "N".
792
Andrey Ryabinin0b24bec2015-02-13 14:39:17 -0800793source "lib/Kconfig.kasan"
794
Dave Hansen0610c8a2013-07-01 13:04:43 -0700795endmenu # "Memory Debugging"
796
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797config DEBUG_SHIRQ
798 bool "Debug shared IRQ handlers"
Martin Schwidefsky0244ad02013-08-30 09:39:53 +0200799 depends on DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 help
801 Enable this to generate a spurious interrupt as soon as a shared
802 interrupt handler is registered, and just before one is deregistered.
803 Drivers ought to be able to handle interrupts coming in at those
804 points; some don't and need to be caught.
805
Changbin Duf43a2892019-12-06 17:03:54 -0800806menu "Debug Oops, Lockups and Hangs"
807
808config PANIC_ON_OOPS
809 bool "Panic on Oops"
810 help
811 Say Y here to enable the kernel to panic when it oopses. This
812 has the same effect as setting oops=panic on the kernel command
813 line.
814
815 This feature is useful to ensure that the kernel does not do
816 anything erroneous after an oops which could result in data
817 corruption or other issues.
818
819 Say N if unsure.
820
821config PANIC_ON_OOPS_VALUE
822 int
823 range 0 1
824 default 0 if !PANIC_ON_OOPS
825 default 1 if PANIC_ON_OOPS
826
827config PANIC_TIMEOUT
828 int "panic timeout"
829 default 0
830 help
831 Set the timeout value (in seconds) until a reboot occurs when the
832 the kernel panics. If n = 0, then we wait forever. A timeout
833 value n > 0 will wait n seconds before rebooting, while a timeout
834 value n < 0 will reboot immediately.
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700835
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836config LOCKUP_DETECTOR
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700837 bool
838
839config SOFTLOCKUP_DETECTOR
840 bool "Detect Soft Lockups"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 depends on DEBUG_KERNEL && !S390
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700842 select LOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843 help
844 Say Y here to enable the kernel to act as a watchdog to detect
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700845 soft lockups.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846
847 Softlockups are bugs that cause the kernel to loop in kernel
848 mode for more than 20 seconds, without giving other tasks a
849 chance to run. The current stack trace is displayed upon
850 detection and the system will stay locked up.
851
Randy Dunlap5f00ae02018-04-10 16:32:51 -0700852config BOOTPARAM_SOFTLOCKUP_PANIC
853 bool "Panic (Reboot) On Soft Lockups"
854 depends on SOFTLOCKUP_DETECTOR
855 help
856 Say Y here to enable the kernel to panic on "soft lockups",
857 which are bugs that cause the kernel to loop in kernel
858 mode for more than 20 seconds (configurable using the watchdog_thresh
859 sysctl), without giving other tasks a chance to run.
860
861 The panic can be used in combination with panic_timeout,
862 to cause the system to reboot automatically after a
863 lockup has been detected. This feature is useful for
864 high-availability systems that have uptime guarantees and
865 where a lockup must be resolved ASAP.
866
867 Say N if unsure.
868
869config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
870 int
871 depends on SOFTLOCKUP_DETECTOR
872 range 0 1
873 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
874 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
875
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700876config HARDLOCKUP_DETECTOR_PERF
877 bool
878 select SOFTLOCKUP_DETECTOR
879
880#
Thomas Gleixner7edaeb62017-08-15 09:50:13 +0200881# Enables a timestamp based low pass filter to compensate for perf based
882# hard lockup detection which runs too fast due to turbo modes.
883#
884config HARDLOCKUP_CHECK_TIMESTAMP
885 bool
886
887#
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700888# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
889# lockup detector rather than the perf based detector.
890#
891config HARDLOCKUP_DETECTOR
892 bool "Detect Hard Lockups"
893 depends on DEBUG_KERNEL && !S390
894 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
895 select LOCKUP_DETECTOR
896 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
897 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
898 help
899 Say Y here to enable the kernel to act as a watchdog to detect
900 hard lockups.
901
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902 Hardlockups are bugs that cause the CPU to loop in kernel mode
903 for more than 10 seconds, without letting other interrupts have a
904 chance to run. The current stack trace is displayed upon detection
905 and the system will stay locked up.
906
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907config BOOTPARAM_HARDLOCKUP_PANIC
908 bool "Panic (Reboot) On Hard Lockups"
909 depends on HARDLOCKUP_DETECTOR
910 help
911 Say Y here to enable the kernel to panic on "hard lockups",
912 which are bugs that cause the kernel to loop in kernel
913 mode with interrupts disabled for more than 10 seconds (configurable
914 using the watchdog_thresh sysctl).
915
916 Say N if unsure.
917
918config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
919 int
920 depends on HARDLOCKUP_DETECTOR
921 range 0 1
922 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
923 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
924
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925config DETECT_HUNG_TASK
926 bool "Detect Hung Tasks"
927 depends on DEBUG_KERNEL
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700928 default SOFTLOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929 help
930 Say Y here to enable the kernel to detect "hung tasks",
931 which are bugs that cause the task to be stuck in
Vivien Didelot96b03ab2016-09-22 16:55:13 -0400932 uninterruptible "D" state indefinitely.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933
934 When a hung task is detected, the kernel will print the
935 current stack trace (which you should report), but the
936 task will stay in uninterruptible state. If lockdep is
937 enabled then all held locks will also be reported. This
938 feature has negligible overhead.
Al Viro871751e2006-03-25 03:06:39 -0800939
940config DEFAULT_HUNG_TASK_TIMEOUT
941 int "Default timeout for hung task detection (in seconds)"
942 depends on DETECT_HUNG_TASK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943 default 120
944 help
Ingo Molnar8637c092006-07-03 00:24:38 -0700945 This option controls the default timeout (in seconds) used
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946 to determine when a task has become non-responsive and should
947 be considered hung.
948
949 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
950 sysctl or by writing a value to
951 /proc/sys/kernel/hung_task_timeout_secs.
952
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700953 A timeout of 0 disables the check. The default is two minutes.
954 Keeping the default should be fine in most cases.
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700955
956config BOOTPARAM_HUNG_TASK_PANIC
957 bool "Panic (Reboot) On Hung Tasks"
958 depends on DETECT_HUNG_TASK
959 help
960 Say Y here to enable the kernel to panic on "hung tasks",
961 which are bugs that cause the kernel to leave a task stuck
962 in uninterruptible "D" state.
963
964 The panic can be used in combination with panic_timeout,
Thomas Gleixner61a87122006-06-27 02:54:56 -0700965 to cause the system to reboot automatically after a
966 hung task has been detected. This feature is useful for
Roman Zippela1583d32006-06-27 02:55:00 -0700967 high-availability systems that have uptime guarantees and
Thomas Gleixner61a87122006-06-27 02:54:56 -0700968 where a hung tasks must be resolved ASAP.
969
970 Say N if unsure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100972config BOOTPARAM_HUNG_TASK_PANIC_VALUE
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973 int
974 depends on DETECT_HUNG_TASK
975 range 0 1
976 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
977 default 1 if BOOTPARAM_HUNG_TASK_PANIC
978
Tejun Heo82607adc2015-12-08 11:28:04 -0500979config WQ_WATCHDOG
980 bool "Detect Workqueue Stalls"
981 depends on DEBUG_KERNEL
982 help
983 Say Y here to enable stall detection on workqueues. If a
984 worker pool doesn't make forward progress on a pending work
985 item for over a given amount of time, 30s by default, a
986 warning message is printed along with dump of workqueue
987 state. This can be configured through kernel parameter
988 "workqueue.watchdog_thresh" and its sysfs counterpart.
989
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700990endmenu # "Debug lockups and hangs"
991
Changbin Duebebdd02019-12-06 17:04:00 -0800992menu "Scheduler Debugging"
Jason Baron5800dc32013-11-25 23:23:04 +0000993
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994config SCHED_DEBUG
995 bool "Collect scheduler debugging info"
996 depends on DEBUG_KERNEL && PROC_FS
997 default y
998 help
999 If you say Y here, the /proc/sched_debug file will be provided
1000 that can help debug the scheduler. The runtime overhead of this
1001 option is minimal.
1002
Naveen N. Raof6db8342015-06-25 23:53:37 +05301003config SCHED_INFO
1004 bool
1005 default n
1006
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007config SCHEDSTATS
1008 bool "Collect scheduler statistics"
1009 depends on DEBUG_KERNEL && PROC_FS
Naveen N. Raof6db8342015-06-25 23:53:37 +05301010 select SCHED_INFO
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 help
1012 If you say Y here, additional code will be inserted into the
1013 scheduler and related routines to collect statistics about
1014 scheduler behavior and provide them in /proc/schedstat. These
1015 stats may be useful for both tuning and debugging the scheduler
1016 If you aren't debugging the scheduler or trying to tune a specific
1017 application, you can say N to avoid the very slight overhead
1018 this adds.
1019
Changbin Duebebdd02019-12-06 17:04:00 -08001020endmenu
Aaron Tomlin0d9e2632014-09-12 14:16:19 +01001021
John Stultz3c17ad12015-03-11 21:16:32 -07001022config DEBUG_TIMEKEEPING
1023 bool "Enable extra timekeeping sanity checking"
1024 help
1025 This option will enable additional timekeeping sanity checks
1026 which may be helpful when diagnosing issues where timekeeping
1027 problems are suspected.
1028
1029 This may include checks in the timekeeping hotpaths, so this
1030 option may have a (very small) performance impact to some
1031 workloads.
1032
1033 If unsure, say N.
1034
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035config DEBUG_PREEMPT
1036 bool "Debug preemptible kernel"
Sebastian Andrzej Siewior9f472862019-10-15 21:18:19 +02001037 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038 default y
1039 help
1040 If you say Y here then the kernel will use a debug variant of the
1041 commonly used smp_processor_id() function and will print warnings
1042 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1043 will detect preemption count underflows.
1044
Dave Hansen9eade162013-07-01 13:04:47 -07001045menu "Lock Debugging (spinlocks, mutexes, etc...)"
1046
Waiman Longf07cbeb2018-03-30 17:27:59 -04001047config LOCK_DEBUGGING_SUPPORT
1048 bool
1049 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1050 default y
1051
Waiman Long19193bc2018-03-30 17:28:00 -04001052config PROVE_LOCKING
1053 bool "Lock debugging: prove locking correctness"
1054 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1055 select LOCKDEP
1056 select DEBUG_SPINLOCK
1057 select DEBUG_MUTEXES
1058 select DEBUG_RT_MUTEXES if RT_MUTEXES
Waiman Longc71fd892019-05-20 16:59:00 -04001059 select DEBUG_RWSEMS
Waiman Long19193bc2018-03-30 17:28:00 -04001060 select DEBUG_WW_MUTEX_SLOWPATH
1061 select DEBUG_LOCK_ALLOC
1062 select TRACE_IRQFLAGS
1063 default n
1064 help
1065 This feature enables the kernel to prove that all locking
1066 that occurs in the kernel runtime is mathematically
1067 correct: that under no circumstance could an arbitrary (and
1068 not yet triggered) combination of observed locking
1069 sequences (on an arbitrary number of CPUs, running an
1070 arbitrary number of tasks and interrupt contexts) cause a
1071 deadlock.
1072
1073 In short, this feature enables the kernel to report locking
1074 related deadlocks before they actually occur.
1075
1076 The proof does not depend on how hard and complex a
1077 deadlock scenario would be to trigger: how many
1078 participant CPUs, tasks and irq-contexts would be needed
1079 for it to trigger. The proof also does not depend on
1080 timing: if a race and a resulting deadlock is possible
1081 theoretically (no matter how unlikely the race scenario
1082 is), it will be proven so and will immediately be
1083 reported by the kernel (once the event is observed that
1084 makes the deadlock theoretically possible).
1085
1086 If a deadlock is impossible (i.e. the locking rules, as
1087 observed by the kernel, are mathematically correct), the
1088 kernel reports nothing.
1089
1090 NOTE: this feature can also be enabled for rwlocks, mutexes
1091 and rwsems - in which case all dependencies between these
1092 different locking variants are observed and mapped too, and
1093 the proof of observed correctness is also maintained for an
1094 arbitrary combination of these separate locking variants.
1095
Mauro Carvalho Chehab387b1462019-04-10 08:32:41 -03001096 For more details, see Documentation/locking/lockdep-design.rst.
Waiman Long19193bc2018-03-30 17:28:00 -04001097
Peter Zijlstrade8f5e42020-03-21 12:26:01 +01001098config PROVE_RAW_LOCK_NESTING
1099 bool "Enable raw_spinlock - spinlock nesting checks"
1100 depends on PROVE_LOCKING
1101 default n
1102 help
1103 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1104 that the lock nesting rules for PREEMPT_RT enabled kernels are
1105 not violated.
1106
1107 NOTE: There are known nesting problems. So if you enable this
1108 option expect lockdep splats until these problems have been fully
1109 addressed which is work in progress. This config switch allows to
1110 identify and analyze these problems. It will be removed and the
1111 check permanentely enabled once the main issues have been fixed.
1112
1113 If unsure, select N.
1114
Waiman Long19193bc2018-03-30 17:28:00 -04001115config LOCK_STAT
1116 bool "Lock usage statistics"
1117 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1118 select LOCKDEP
1119 select DEBUG_SPINLOCK
1120 select DEBUG_MUTEXES
1121 select DEBUG_RT_MUTEXES if RT_MUTEXES
1122 select DEBUG_LOCK_ALLOC
1123 default n
1124 help
1125 This feature enables tracking lock contention points
1126
Mauro Carvalho Chehab387b1462019-04-10 08:32:41 -03001127 For more details, see Documentation/locking/lockstat.rst
Waiman Long19193bc2018-03-30 17:28:00 -04001128
1129 This also enables lock events required by "perf lock",
1130 subcommand of perf.
1131 If you want to use "perf lock", you also need to turn on
1132 CONFIG_EVENT_TRACING.
1133
1134 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1135 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1136
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137config DEBUG_RT_MUTEXES
1138 bool "RT Mutex debugging, deadlock detection"
1139 depends on DEBUG_KERNEL && RT_MUTEXES
1140 help
1141 This allows rt mutex semantics violations and rt mutex related
1142 deadlocks (lockups) to be detected and reported automatically.
1143
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001145 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +05301147 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -07001148 help
1149 Say Y here and build SMP to catch missing spinlock initialization
1150 and certain other kinds of spinlock errors commonly made. This is
1151 best used in conjunction with the NMI watchdog so that spinlock
1152 deadlocks are also debuggable.
1153
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001154config DEBUG_MUTEXES
1155 bool "Mutex debugging: basic checks"
1156 depends on DEBUG_KERNEL
1157 help
1158 This feature allows mutex semantics violations to be detected and
1159 reported.
1160
Daniel Vetter23010022013-06-20 13:31:17 +02001161config DEBUG_WW_MUTEX_SLOWPATH
1162 bool "Wait/wound mutex debugging: Slowpath testing"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001163 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Daniel Vetter23010022013-06-20 13:31:17 +02001164 select DEBUG_LOCK_ALLOC
1165 select DEBUG_SPINLOCK
1166 select DEBUG_MUTEXES
1167 help
1168 This feature enables slowpath testing for w/w mutex users by
1169 injecting additional -EDEADLK wound/backoff cases. Together with
1170 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1171 will test all possible w/w mutex interface abuse with the
1172 exception of simply not acquiring all the required locks.
Rob Clark4d692372014-08-27 11:19:26 -04001173 Note that this feature can introduce significant overhead, so
1174 it really should not be enabled in a production or distro kernel,
1175 even a debug kernel. If you are a driver writer, enable it. If
1176 you are a distro, do not.
Daniel Vetter23010022013-06-20 13:31:17 +02001177
Waiman Long5149cba2018-03-30 17:27:58 -04001178config DEBUG_RWSEMS
1179 bool "RW Semaphore debugging: basic checks"
Waiman Longc71fd892019-05-20 16:59:00 -04001180 depends on DEBUG_KERNEL
Waiman Long5149cba2018-03-30 17:27:58 -04001181 help
Waiman Longc71fd892019-05-20 16:59:00 -04001182 This debugging feature allows mismatched rw semaphore locks
1183 and unlocks to be detected and reported.
Waiman Long5149cba2018-03-30 17:27:58 -04001184
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001185config DEBUG_LOCK_ALLOC
1186 bool "Lock debugging: detect incorrect freeing of live locks"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001187 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001188 select DEBUG_SPINLOCK
1189 select DEBUG_MUTEXES
Peter Zijlstraf5694782016-09-19 12:15:37 +02001190 select DEBUG_RT_MUTEXES if RT_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001191 select LOCKDEP
1192 help
1193 This feature will check whether any held lock (spinlock, rwlock,
1194 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1195 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1196 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1197 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1198 held during task exit.
1199
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001200config LOCKDEP
1201 bool
Waiman Longf07cbeb2018-03-30 17:27:59 -04001202 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001203 select STACKTRACE
Stefan Agnerf9b58e82018-09-30 23:02:33 +01001204 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001205 select KALLSYMS
1206 select KALLSYMS_ALL
1207
Daniel Jordan395102d2017-04-10 11:50:52 -04001208config LOCKDEP_SMALL
1209 bool
1210
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001211config DEBUG_LOCKDEP
1212 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -07001213 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001214 help
1215 If you say Y here, the lock dependency engine will do
1216 additional runtime checks to debug itself, at the price
1217 of more runtime overhead.
1218
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001219config DEBUG_ATOMIC_SLEEP
1220 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +02001221 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 depends on DEBUG_KERNEL
Christoph Hellwig87a4c372018-07-31 13:39:32 +02001223 depends on !ARCH_NO_PREEMPT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224 help
1225 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001226 noisy if they are called inside atomic sections: when a spinlock is
1227 held, inside an rcu read side critical section, inside preempt disabled
1228 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229
Ingo Molnarcae2ed92006-07-03 00:24:48 -07001230config DEBUG_LOCKING_API_SELFTESTS
1231 bool "Locking API boot-time self-tests"
1232 depends on DEBUG_KERNEL
1233 help
1234 Say Y here if you want the kernel to run a short self-test during
1235 bootup. The self-test checks whether common types of locking bugs
1236 are detected by debugging mechanisms or not. (if you disable
1237 lock debugging then those bugs wont be detected of course.)
1238 The following locking APIs are covered: spinlocks, rwlocks,
1239 mutexes and rwsems.
1240
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001241config LOCK_TORTURE_TEST
1242 tristate "torture tests for locking"
1243 depends on DEBUG_KERNEL
1244 select TORTURE_TEST
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001245 help
1246 This option provides a kernel module that runs torture tests
1247 on kernel locking primitives. The kernel module may be built
1248 after the fact on the running kernel to be tested, if desired.
1249
1250 Say Y here if you want kernel locking-primitive torture tests
1251 to be built into the kernel.
1252 Say M if you want these torture tests to build as a module.
1253 Say N if you are unsure.
1254
Chris Wilsonf2a5fec2016-12-01 11:47:06 +00001255config WW_MUTEX_SELFTEST
1256 tristate "Wait/wound mutex selftests"
1257 help
1258 This option provides a kernel module that runs tests on the
1259 on the struct ww_mutex locking API.
1260
1261 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1262 with this test harness.
1263
1264 Say M if you want these self tests to build as a module.
1265 Say N if you are unsure.
1266
Dave Hansen9eade162013-07-01 13:04:47 -07001267endmenu # lock debugging
1268
1269config TRACE_IRQFLAGS
1270 bool
1271 help
1272 Enables hooks to interrupt enabling and disabling for
1273 either tracing or lock debugging.
1274
Ingo Molnar8637c092006-07-03 00:24:38 -07001275config STACKTRACE
Dave Jones0c38e1f2014-08-29 15:18:35 -07001276 bool "Stack backtrace support"
Ingo Molnar8637c092006-07-03 00:24:38 -07001277 depends on STACKTRACE_SUPPORT
Dave Jones0c38e1f2014-08-29 15:18:35 -07001278 help
1279 This option causes the kernel to create a /proc/pid/stack for
1280 every process, showing its current stack trace.
1281 It is also used by various kernel debugging features that require
1282 stack trace generation.
Ingo Molnar8637c092006-07-03 00:24:38 -07001283
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001284config WARN_ALL_UNSEEDED_RANDOM
1285 bool "Warn for all uses of unseeded randomness"
1286 default n
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001287 help
1288 Some parts of the kernel contain bugs relating to their use of
1289 cryptographically secure random numbers before it's actually possible
1290 to generate those numbers securely. This setting ensures that these
1291 flaws don't go unnoticed, by enabling a message, should this ever
1292 occur. This will allow people with obscure setups to know when things
1293 are going wrong, so that they might contact developers about fixing
1294 it.
1295
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001296 Unfortunately, on some models of some architectures getting
1297 a fully seeded CRNG is extremely difficult, and so this can
1298 result in dmesg getting spammed for a surprisingly long
1299 time. This is really bad from a security perspective, and
1300 so architecture maintainers really need to do what they can
1301 to get the CRNG seeded sooner after the system is booted.
Thibaut Sautereau4c5d1142018-09-04 15:46:23 -07001302 However, since users cannot do anything actionable to
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001303 address this, by default the kernel will issue only a single
1304 warning for the first use of unseeded randomness.
1305
1306 Say Y here if you want to receive warnings for all uses of
1307 unseeded randomness. This will be of use primarily for
Thibaut Sautereau4c5d1142018-09-04 15:46:23 -07001308 those developers interested in improving the security of
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001309 Linux kernels running on their architecture (or
1310 subarchitecture).
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001311
Linus Torvalds1da177e2005-04-16 15:20:36 -07001312config DEBUG_KOBJECT
1313 bool "kobject debugging"
1314 depends on DEBUG_KERNEL
1315 help
1316 If you say Y here, some extra kobject debugging messages will be sent
Mike Rapoportaca52c32018-10-30 15:07:44 -07001317 to the syslog.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318
Russell Kingc817a672013-06-27 15:06:14 +01001319config DEBUG_KOBJECT_RELEASE
1320 bool "kobject release debugging"
Linus Torvalds2a999aa2013-10-29 08:33:36 -07001321 depends on DEBUG_OBJECTS_TIMERS
Russell Kingc817a672013-06-27 15:06:14 +01001322 help
1323 kobjects are reference counted objects. This means that their
1324 last reference count put is not predictable, and the kobject can
1325 live on past the point at which a driver decides to drop it's
1326 initial reference to the kobject gained on allocation. An
1327 example of this would be a struct device which has just been
1328 unregistered.
1329
1330 However, some buggy drivers assume that after such an operation,
1331 the memory backing the kobject can be immediately freed. This
1332 goes completely against the principles of a refcounted object.
1333
1334 If you say Y here, the kernel will delay the release of kobjects
1335 on the last reference count to improve the visibility of this
1336 kind of kobject release bug.
1337
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001338config HAVE_DEBUG_BUGVERBOSE
1339 bool
1340
Changbin Du3be5cbc2019-12-06 17:03:48 -08001341menu "Debug kernel data structures"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001342
Dave Jones199a9af2006-09-29 01:59:00 -07001343config DEBUG_LIST
1344 bool "Debug linked list manipulation"
Arnd Bergmann4520bcb2016-08-26 17:42:00 +02001345 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
Dave Jones199a9af2006-09-29 01:59:00 -07001346 help
1347 Enable this to turn on extended checks in the linked-list
1348 walking routines.
1349
1350 If unsure, say N.
1351
Davidlohr Bueso8e18fae2019-05-14 15:42:46 -07001352config DEBUG_PLIST
Dan Streetmanb8cfff62014-06-04 16:11:54 -07001353 bool "Debug priority linked list manipulation"
1354 depends on DEBUG_KERNEL
1355 help
1356 Enable this to turn on extended checks in the priority-ordered
1357 linked-list (plist) walking routines. This checks the entire
1358 list multiple times during each manipulation.
1359
1360 If unsure, say N.
1361
Jens Axboed6ec0842007-10-22 20:01:06 +02001362config DEBUG_SG
1363 bool "Debug SG table operations"
1364 depends on DEBUG_KERNEL
1365 help
1366 Enable this to turn on checks on scatter-gather tables. This can
1367 help find problems with drivers that do not properly initialize
1368 their sg tables.
1369
1370 If unsure, say N.
1371
Arjan van de Ven1b2439d2008-08-15 15:29:38 -07001372config DEBUG_NOTIFIERS
1373 bool "Debug notifier call chains"
1374 depends on DEBUG_KERNEL
1375 help
1376 Enable this to turn on sanity checking for notifier call chains.
1377 This is most useful for kernel developers to make sure that
1378 modules properly unregister themselves from notifier chains.
1379 This is a relatively cheap check but if you care about maximum
1380 performance, say N.
1381
Changbin Du3be5cbc2019-12-06 17:03:48 -08001382config BUG_ON_DATA_CORRUPTION
1383 bool "Trigger a BUG when data corruption is detected"
1384 select DEBUG_LIST
1385 help
1386 Select this option if the kernel should BUG when it encounters
1387 data corruption in kernel memory structures when they get checked
1388 for validity.
1389
1390 If unsure, say N.
1391
1392endmenu
1393
David Howellse0e81732009-09-02 09:13:40 +01001394config DEBUG_CREDENTIALS
1395 bool "Debug credential management"
1396 depends on DEBUG_KERNEL
1397 help
1398 Enable this to turn on some debug checking for credential
1399 management. The additional code keeps track of the number of
1400 pointers from task_structs to any given cred struct, and checks to
1401 see that this number never exceeds the usage count of the cred
1402 struct.
1403
1404 Furthermore, if SELinux is enabled, this also checks that the
1405 security pointer in the cred struct is never seen to be invalid.
1406
1407 If unsure, say N.
1408
Paul E. McKenney43a0a2a2017-05-17 09:19:44 -07001409source "kernel/rcu/Kconfig.debug"
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001410
Tejun Heof303fccb2016-02-09 17:59:38 -05001411config DEBUG_WQ_FORCE_RR_CPU
1412 bool "Force round-robin CPU selection for unbound work items"
1413 depends on DEBUG_KERNEL
1414 default n
1415 help
1416 Workqueue used to implicitly guarantee that work items queued
1417 without explicit CPU specified are put on the local CPU. This
1418 guarantee is no longer true and while local CPU is still
1419 preferred work items may be put on foreign CPUs. Kernel
1420 parameter "workqueue.debug_force_rr_cpu" is added to force
1421 round-robin CPU selection to flush out usages which depend on the
1422 now broken guarantee. This config option enables the debug
1423 feature by default. When enabled, memory and cache locality will
1424 be impacted.
1425
Tejun Heo870d6652008-08-25 19:47:25 +09001426config DEBUG_BLOCK_EXT_DEVT
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -08001427 bool "Force extended block device numbers and spread them"
Tejun Heo870d6652008-08-25 19:47:25 +09001428 depends on DEBUG_KERNEL
1429 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +02001430 default n
Tejun Heo870d6652008-08-25 19:47:25 +09001431 help
Tejun Heo0e11e342008-10-13 10:46:01 +02001432 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1433 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1434 YOU ARE DOING. Distros, please enable this and fix whatever
1435 is broken.
1436
Tejun Heo870d6652008-08-25 19:47:25 +09001437 Conventionally, block device numbers are allocated from
1438 predetermined contiguous area. However, extended block area
1439 may introduce non-contiguous block device numbers. This
1440 option forces most block device numbers to be allocated from
1441 the extended space and spreads them to discover kernel or
1442 userland code paths which assume predetermined contiguous
1443 device number allocation.
1444
Tejun Heo55dc7db2008-09-01 13:44:35 +02001445 Note that turning on this debug option shuffles all the
1446 device numbers for all IDE and SCSI devices including libata
1447 ones, so root partition specified using device number
1448 directly (via rdev or root=MAJ:MIN) won't work anymore.
1449 Textual device names (root=/dev/sdXn) will continue to work.
1450
Tejun Heo870d6652008-08-25 19:47:25 +09001451 Say N if you are unsure.
1452
Thomas Gleixner757c9892016-02-26 18:43:32 +00001453config CPU_HOTPLUG_STATE_CONTROL
1454 bool "Enable CPU hotplug state control"
1455 depends on DEBUG_KERNEL
1456 depends on HOTPLUG_CPU
1457 default n
1458 help
1459 Allows to write steps between "offline" and "online" to the CPUs
1460 sysfs target file so states can be stepped granular. This is a debug
1461 option for now as the hotplug machinery cannot be stopped and
1462 restarted at arbitrary points yet.
1463
1464 Say N if your are unsure.
1465
Changbin Du09a74952019-12-06 17:03:51 -08001466config LATENCYTOP
1467 bool "Latency measuring infrastructure"
1468 depends on DEBUG_KERNEL
1469 depends on STACKTRACE_SUPPORT
1470 depends on PROC_FS
1471 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1472 select KALLSYMS
1473 select KALLSYMS_ALL
1474 select STACKTRACE
1475 select SCHEDSTATS
1476 select SCHED_DEBUG
1477 help
1478 Enable this option if you want to use the LatencyTOP tool
1479 to find out which userspace is blocking on what kernel operations.
1480
1481source "kernel/trace/Kconfig"
1482
1483config PROVIDE_OHCI1394_DMA_INIT
1484 bool "Remote debugging over FireWire early on boot"
1485 depends on PCI && X86
1486 help
1487 If you want to debug problems which hang or crash the kernel early
1488 on boot and the crashing machine has a FireWire port, you can use
1489 this feature to remotely access the memory of the crashed machine
1490 over FireWire. This employs remote DMA as part of the OHCI1394
1491 specification which is now the standard for FireWire controllers.
1492
1493 With remote DMA, you can monitor the printk buffer remotely using
1494 firescope and access all memory below 4GB using fireproxy from gdb.
1495 Even controlling a kernel debugger is possible using remote DMA.
1496
1497 Usage:
1498
1499 If ohci1394_dma=early is used as boot parameter, it will initialize
1500 all OHCI1394 controllers which are found in the PCI config space.
1501
1502 As all changes to the FireWire bus such as enabling and disabling
1503 devices cause a bus reset and thereby disable remote DMA for all
1504 devices, be sure to have the cable plugged and FireWire enabled on
1505 the debugging host before booting the debug target for debugging.
1506
1507 This code (~1k) is freed after boot. By then, the firewire stack
1508 in charge of the OHCI-1394 controllers should be used instead.
1509
1510 See Documentation/debugging-via-ohci1394.txt for more information.
1511
Changbin Du045f6d72019-12-17 20:51:56 -08001512source "samples/Kconfig"
1513
1514config ARCH_HAS_DEVMEM_IS_ALLOWED
1515 bool
1516
1517config STRICT_DEVMEM
1518 bool "Filter access to /dev/mem"
1519 depends on MMU && DEVMEM
1520 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
1521 default y if PPC || X86 || ARM64
1522 help
1523 If this option is disabled, you allow userspace (root) access to all
1524 of memory, including kernel and userspace memory. Accidental
1525 access to this is obviously disastrous, but specific access can
1526 be used by people debugging the kernel. Note that with PAT support
1527 enabled, even in this case there are restrictions on /dev/mem
1528 use due to the cache aliasing requirements.
1529
1530 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1531 file only allows userspace access to PCI space and the BIOS code and
1532 data regions. This is sufficient for dosemu and X and all common
1533 users of /dev/mem.
1534
1535 If in doubt, say Y.
1536
1537config IO_STRICT_DEVMEM
1538 bool "Filter I/O access to /dev/mem"
1539 depends on STRICT_DEVMEM
1540 help
1541 If this option is disabled, you allow userspace (root) access to all
1542 io-memory regardless of whether a driver is actively using that
1543 range. Accidental access to this is obviously disastrous, but
1544 specific access can be used by people debugging kernel drivers.
1545
1546 If this option is switched on, the /dev/mem file only allows
1547 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1548 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1549 if the driver using a given range cannot be disabled.
1550
1551 If in doubt, say Y.
1552
1553menu "$(SRCARCH) Debugging"
1554
1555source "arch/$(SRCARCH)/Kconfig.debug"
1556
1557endmenu
1558
1559menu "Kernel Testing and Coverage"
1560
Changbin Du09a74952019-12-06 17:03:51 -08001561source "lib/kunit/Kconfig"
1562
Akinobu Mita8d438282012-07-30 14:43:02 -07001563config NOTIFIER_ERROR_INJECTION
1564 tristate "Notifier error injection"
1565 depends on DEBUG_KERNEL
1566 select DEBUG_FS
1567 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001568 This option provides the ability to inject artificial errors to
Akinobu Mita8d438282012-07-30 14:43:02 -07001569 specified notifier chain callbacks. It is useful to test the error
1570 handling of notifier call chain failures.
1571
1572 Say N if unsure.
1573
Akinobu Mita048b9c32012-07-30 14:43:07 -07001574config PM_NOTIFIER_ERROR_INJECT
1575 tristate "PM notifier error injection module"
1576 depends on PM && NOTIFIER_ERROR_INJECTION
1577 default m if PM_DEBUG
1578 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001579 This option provides the ability to inject artificial errors to
Akinobu Mita048b9c32012-07-30 14:43:07 -07001580 PM notifier chain callbacks. It is controlled through debugfs
1581 interface /sys/kernel/debug/notifier-error-inject/pm
1582
1583 If the notifier call chain should be failed with some events
1584 notified, write the error code to "actions/<notifier event>/error".
1585
1586 Example: Inject PM suspend error (-12 = -ENOMEM)
1587
1588 # cd /sys/kernel/debug/notifier-error-inject/pm/
1589 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1590 # echo mem > /sys/power/state
1591 bash: echo: write error: Cannot allocate memory
1592
1593 To compile this code as a module, choose M here: the module will
1594 be called pm-notifier-error-inject.
1595
1596 If unsure, say N.
1597
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001598config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1599 tristate "OF reconfig notifier error injection module"
1600 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001601 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001602 This option provides the ability to inject artificial errors to
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001603 OF reconfig notifier chain callbacks. It is controlled
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001604 through debugfs interface under
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001605 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001606
1607 If the notifier call chain should be failed with some events
1608 notified, write the error code to "actions/<notifier event>/error".
1609
1610 To compile this code as a module, choose M here: the module will
Akinobu Mitae12a95f2013-04-30 15:28:49 -07001611 be called of-reconfig-notifier-error-inject.
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001612
1613 If unsure, say N.
1614
Nikolay Aleksandrov02fff962015-11-28 13:45:28 +01001615config NETDEV_NOTIFIER_ERROR_INJECT
1616 tristate "Netdev notifier error injection module"
1617 depends on NET && NOTIFIER_ERROR_INJECTION
1618 help
1619 This option provides the ability to inject artificial errors to
1620 netdevice notifier chain callbacks. It is controlled through debugfs
1621 interface /sys/kernel/debug/notifier-error-inject/netdev
1622
1623 If the notifier call chain should be failed with some events
1624 notified, write the error code to "actions/<notifier event>/error".
1625
1626 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1627
1628 # cd /sys/kernel/debug/notifier-error-inject/netdev
1629 # echo -22 > actions/NETDEV_CHANGEMTU/error
1630 # ip link set eth0 mtu 1024
1631 RTNETLINK answers: Invalid argument
1632
1633 To compile this code as a module, choose M here: the module will
1634 be called netdev-notifier-error-inject.
1635
1636 If unsure, say N.
1637
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001638config FUNCTION_ERROR_INJECTION
1639 def_bool y
1640 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1641
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001642config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001643 bool "Fault-injection framework"
1644 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001645 help
1646 Provide fault-injection framework.
1647 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001648
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001649config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001650 bool "Fault-injection capability for kmalloc"
1651 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001652 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001653 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001654 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001655
Akinobu Mita933e3122006-12-08 02:39:45 -08001656config FAIL_PAGE_ALLOC
1657 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001658 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001659 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001660 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001661
Akinobu Mitac17bb492006-12-08 02:39:46 -08001662config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001663 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001664 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001665 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001666 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001667
Jens Axboe581d4e22008-09-14 05:56:33 -07001668config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d01432010-07-21 16:05:53 +09001669 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001670 depends on FAULT_INJECTION && BLOCK
1671 help
1672 Provide fault-injection capability on end IO handling. This
1673 will make the block layer "forget" an interrupt as configured,
1674 thus exercising the error handling.
1675
1676 Only works with drivers that use the generic timeout handling,
1677 for others it wont do anything.
1678
Davidlohr Buesoab51fba2015-06-29 23:26:02 -07001679config FAIL_FUTEX
1680 bool "Fault-injection capability for futexes"
1681 select DEBUG_FS
1682 depends on FAULT_INJECTION && FUTEX
1683 help
1684 Provide fault-injection capability for futexes.
1685
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001686config FAULT_INJECTION_DEBUG_FS
1687 bool "Debugfs entries for fault-injection capabilities"
1688 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1689 help
1690 Enable configuration of fault-injection capabilities via debugfs.
1691
Masami Hiramatsu4b1a29a2018-01-13 02:56:03 +09001692config FAIL_FUNCTION
1693 bool "Fault-injection capability for functions"
1694 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1695 help
1696 Provide function-based fault-injection capability.
1697 This will allow you to override a specific function with a return
1698 with given return value. As a result, function caller will see
1699 an error value and have to handle it. This is useful to test the
1700 error handling in various subsystems.
1701
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001702config FAIL_MMC_REQUEST
1703 bool "Fault-injection capability for MMC IO"
1704 depends on FAULT_INJECTION_DEBUG_FS && MMC
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001705 help
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001706 Provide fault-injection capability for MMC IO.
1707 This will make the mmc core return data errors. This is
1708 useful to test the error handling in the mmc block device
1709 and to test how the mmc host driver handles retries from
1710 the block device.
Akinobu Mita1df49002007-02-20 13:57:56 -08001711
1712config FAULT_INJECTION_STACKTRACE_FILTER
1713 bool "stacktrace filter for fault-injection capabilities"
1714 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001715 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001716 select STACKTRACE
Stefan Agnerf9b58e82018-09-30 23:02:33 +01001717 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
Akinobu Mita1df49002007-02-20 13:57:56 -08001718 help
1719 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001720
Changbin Du09a74952019-12-06 17:03:51 -08001721config ARCH_HAS_KCOV
1722 bool
Arjan van de Ven97455122008-01-25 21:08:34 +01001723 help
Changbin Du09a74952019-12-06 17:03:51 -08001724 An architecture should select this when it can successfully
1725 build and run with CONFIG_KCOV. This typically requires
1726 disabling instrumentation for some early boot code.
Arjan van de Ven97455122008-01-25 21:08:34 +01001727
Changbin Du09a74952019-12-06 17:03:51 -08001728config CC_HAS_SANCOV_TRACE_PC
1729 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001730
Changbin Du09a74952019-12-06 17:03:51 -08001731
1732config KCOV
1733 bool "Code coverage for fuzzing"
1734 depends on ARCH_HAS_KCOV
1735 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1736 select DEBUG_FS
1737 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001738 help
Changbin Du09a74952019-12-06 17:03:51 -08001739 KCOV exposes kernel code coverage information in a form suitable
1740 for coverage-guided fuzzing (randomized testing).
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001741
Changbin Du09a74952019-12-06 17:03:51 -08001742 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1743 different machines and across reboots. If you need stable PC values,
1744 disable RANDOMIZE_BASE.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001745
Changbin Du09a74952019-12-06 17:03:51 -08001746 For more details, see Documentation/dev-tools/kcov.rst.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001747
Changbin Du09a74952019-12-06 17:03:51 -08001748config KCOV_ENABLE_COMPARISONS
1749 bool "Enable comparison operands collection by KCOV"
1750 depends on KCOV
1751 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1752 help
1753 KCOV also exposes operands of every comparison in the instrumented
1754 code along with operand sizes and PCs of the comparison instructions.
1755 These operands can be used by fuzzing engines to improve the quality
1756 of fuzzing coverage.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001757
Changbin Du09a74952019-12-06 17:03:51 -08001758config KCOV_INSTRUMENT_ALL
1759 bool "Instrument all code by default"
1760 depends on KCOV
1761 default y
1762 help
1763 If you are doing generic system call fuzzing (like e.g. syzkaller),
1764 then you will want to instrument the whole kernel and you should
1765 say y here. If you are doing more targeted fuzzing (like e.g.
1766 filesystem fuzzing with AFL) then you will want to enable coverage
1767 for more specific subsets of files, and should say n here.
Brendan Higgins84bc8092019-09-23 02:02:36 -07001768
Vincent Legolld3deafa2018-02-06 15:38:38 -08001769menuconfig RUNTIME_TESTING_MENU
1770 bool "Runtime Testing"
Anders Roxell908009e82018-02-21 14:46:05 -08001771 def_bool y
Vincent Legolld3deafa2018-02-06 15:38:38 -08001772
1773if RUNTIME_TESTING_MENU
Dave Hansen881c5142013-07-01 13:04:44 -07001774
1775config LKDTM
1776 tristate "Linux Kernel Dump Test Tool Module"
1777 depends on DEBUG_FS
Dave Hansen881c5142013-07-01 13:04:44 -07001778 help
1779 This module enables testing of the different dumping mechanisms by
1780 inducing system failures at predefined crash points.
1781 If you don't need it: say N
1782 Choose M here to compile this code as a module. The module will be
1783 called lkdtm.
1784
1785 Documentation on how to use the module can be found in
Mauro Carvalho Chehab10ffebb2019-06-12 14:52:44 -03001786 Documentation/fault-injection/provoke-crashes.rst
Dave Hansen881c5142013-07-01 13:04:44 -07001787
1788config TEST_LIST_SORT
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001789 tristate "Linked list sorting test"
1790 depends on DEBUG_KERNEL || m
Dave Hansen881c5142013-07-01 13:04:44 -07001791 help
1792 Enable this to turn on 'list_sort()' function test. This test is
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001793 executed only once during system boot (so affects only boot time),
1794 or at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001795
1796 If unsure, say N.
1797
Ian Rogers6e246282020-02-13 23:51:29 -08001798config TEST_MIN_HEAP
1799 tristate "Min heap test"
1800 depends on DEBUG_KERNEL || m
1801 help
1802 Enable this to turn on min heap function tests. This test is
1803 executed only once during system boot (so affects only boot time),
1804 or at module load time.
1805
1806 If unsure, say N.
1807
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001808config TEST_SORT
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001809 tristate "Array-based sort test"
1810 depends on DEBUG_KERNEL || m
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001811 help
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001812 This option enables the self-test function of 'sort()' at boot,
1813 or at module load time.
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001814
1815 If unsure, say N.
1816
Dave Hansen881c5142013-07-01 13:04:44 -07001817config KPROBES_SANITY_TEST
1818 bool "Kprobes sanity tests"
1819 depends on DEBUG_KERNEL
1820 depends on KPROBES
Dave Hansen881c5142013-07-01 13:04:44 -07001821 help
1822 This option provides for testing basic kprobes functionality on
Masami Hiramatsu5a6cf772018-06-20 01:05:07 +09001823 boot. Samples of kprobe and kretprobe are inserted and
Dave Hansen881c5142013-07-01 13:04:44 -07001824 verified for functionality.
1825
1826 Say N if you are unsure.
1827
1828config BACKTRACE_SELF_TEST
1829 tristate "Self test for the backtrace code"
1830 depends on DEBUG_KERNEL
Dave Hansen881c5142013-07-01 13:04:44 -07001831 help
1832 This option provides a kernel module that can be used to test
1833 the kernel stack backtrace code. This option is not useful
1834 for distributions or general kernels, but only for kernel
1835 developers working on architecture code.
1836
1837 Note that if you want to also test saved backtraces, you will
1838 have to enable STACKTRACE as well.
1839
1840 Say N if you are unsure.
1841
Michel Lespinasse910a7422012-10-08 16:30:39 -07001842config RBTREE_TEST
1843 tristate "Red-Black tree test"
Cody P Schafer7c993e12013-09-11 14:25:19 -07001844 depends on DEBUG_KERNEL
Michel Lespinasse910a7422012-10-08 16:30:39 -07001845 help
1846 A benchmark measuring the performance of the rbtree library.
1847 Also includes rbtree invariant checks.
1848
Ferdinand Blomqvist4b4f3ac2019-06-20 17:10:33 +03001849config REED_SOLOMON_TEST
1850 tristate "Reed-Solomon library test"
1851 depends on DEBUG_KERNEL || m
1852 select REED_SOLOMON
1853 select REED_SOLOMON_ENC16
1854 select REED_SOLOMON_DEC16
1855 help
1856 This option enables the self-test function of rslib at boot,
1857 or at module load time.
1858
1859 If unsure, say N.
1860
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001861config INTERVAL_TREE_TEST
1862 tristate "Interval tree test"
Davidlohr Bueso0f789b62017-07-10 15:51:43 -07001863 depends on DEBUG_KERNEL
Chris Wilsona88cc102014-03-17 12:21:54 +00001864 select INTERVAL_TREE
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001865 help
1866 A benchmark measuring the performance of the interval tree library
1867
Greg Thelen623fd802013-11-12 15:08:34 -08001868config PERCPU_TEST
1869 tristate "Per cpu operations test"
1870 depends on m && DEBUG_KERNEL
1871 help
1872 Enable this option to build test module which validates per-cpu
1873 operations.
1874
1875 If unsure, say N.
1876
Dave Hansen881c5142013-07-01 13:04:44 -07001877config ATOMIC64_SELFTEST
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001878 tristate "Perform an atomic64_t self-test"
Dave Hansen881c5142013-07-01 13:04:44 -07001879 help
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001880 Enable this option to test the atomic64_t functions at boot or
1881 at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001882
1883 If unsure, say N.
1884
1885config ASYNC_RAID6_TEST
1886 tristate "Self test for hardware accelerated raid6 recovery"
1887 depends on ASYNC_RAID6_RECOV
1888 select ASYNC_MEMCPY
1889 ---help---
1890 This is a one-shot self test that permutes through the
1891 recovery of all the possible two disk failure scenarios for a
1892 N-disk array. Recovery is performed with the asynchronous
1893 raid6 recovery routines, and will optionally use an offload
1894 engine if one is available.
1895
1896 If unsure, say N.
1897
Andy Shevchenko64d1d772015-02-12 15:02:21 -08001898config TEST_HEXDUMP
1899 tristate "Test functions located in the hexdump module at runtime"
1900
Dave Hansen881c5142013-07-01 13:04:44 -07001901config TEST_STRING_HELPERS
1902 tristate "Test functions located in the string_helpers module at runtime"
1903
Tobin C. Harding0b0600c2019-04-05 12:58:59 +11001904config TEST_STRSCPY
1905 tristate "Test strscpy*() family of functions at runtime"
1906
Dave Hansen881c5142013-07-01 13:04:44 -07001907config TEST_KSTRTOX
1908 tristate "Test kstrto*() family of functions at runtime"
1909
Rasmus Villemoes707cc722015-11-06 16:30:29 -08001910config TEST_PRINTF
1911 tristate "Test printf() family of functions at runtime"
1912
David Decotigny5fd003f2016-02-19 09:24:00 -05001913config TEST_BITMAP
1914 tristate "Test bitmap_*() family of functions at runtime"
David Decotigny5fd003f2016-02-19 09:24:00 -05001915 help
1916 Enable this option to test the bitmap functions at boot.
1917
1918 If unsure, say N.
1919
Johannes Berg0e2dc702018-06-20 08:58:30 +02001920config TEST_BITFIELD
1921 tristate "Test bitfield functions at runtime"
1922 help
1923 Enable this option to test the bitfield functions at boot.
1924
1925 If unsure, say N.
1926
Andy Shevchenkocfaff0e2016-05-30 17:40:41 +03001927config TEST_UUID
1928 tristate "Test functions located in the uuid module at runtime"
1929
Matthew Wilcoxad3d6c72017-11-07 14:57:46 -05001930config TEST_XARRAY
1931 tristate "Test the XArray code at runtime"
1932
Rasmus Villemoes455a35a2018-05-08 00:36:28 +02001933config TEST_OVERFLOW
1934 tristate "Test check_*_overflow() functions at runtime"
1935
Thomas Graf7e1e7762014-08-02 11:47:44 +02001936config TEST_RHASHTABLE
Geert Uytterhoeven9d6dbe12015-01-29 15:40:25 +01001937 tristate "Perform selftest on resizable hash table"
Thomas Graf7e1e7762014-08-02 11:47:44 +02001938 help
1939 Enable this option to test the rhashtable functions at boot.
1940
1941 If unsure, say N.
1942
George Spelvin468a9422016-05-26 22:11:51 -04001943config TEST_HASH
1944 tristate "Perform selftest on hash functions"
George Spelvin468a9422016-05-26 22:11:51 -04001945 help
Jason A. Donenfeld2c956a62017-01-08 13:54:00 +01001946 Enable this option to test the kernel's integer (<linux/hash.h>),
1947 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
1948 hash functions on boot (or module load).
George Spelvin468a9422016-05-26 22:11:51 -04001949
1950 This is intended to help people writing architecture-specific
1951 optimized versions. If unsure, say N.
1952
Matthew Wilcox8ab8ba32018-06-18 16:59:29 -04001953config TEST_IDA
1954 tristate "Perform selftest on IDA functions"
1955
Jiri Pirko44091d22017-02-03 10:29:06 +01001956config TEST_PARMAN
1957 tristate "Perform selftest on priority array manager"
Jiri Pirko44091d22017-02-03 10:29:06 +01001958 depends on PARMAN
1959 help
1960 Enable this option to test priority array manager on boot
1961 (or module load).
1962
1963 If unsure, say N.
1964
Daniel Lezcano6aed82d2019-05-27 22:55:19 +02001965config TEST_IRQ_TIMINGS
1966 bool "IRQ timings selftest"
1967 depends on IRQ_TIMINGS
1968 help
1969 Enable this option to test the irq timings code on boot.
1970
1971 If unsure, say N.
1972
Valentin Rothberg8a6f0b42014-10-13 15:51:38 -07001973config TEST_LKM
Kees Cook93e9ef82014-01-23 15:54:37 -08001974 tristate "Test module loading with 'hello world' module"
Kees Cook93e9ef82014-01-23 15:54:37 -08001975 depends on m
1976 help
1977 This builds the "test_module" module that emits "Hello, world"
1978 on printk when loaded. It is designed to be used for basic
1979 evaluation of the module loading subsystem (for example when
1980 validating module verification). It lacks any extra dependencies,
1981 and will not normally be loaded by the system unless explicitly
1982 requested by name.
1983
1984 If unsure, say N.
1985
Uladzislau Rezki (Sony)3f21a6b2019-03-05 15:43:34 -08001986config TEST_VMALLOC
1987 tristate "Test module for stress/performance analysis of vmalloc allocator"
1988 default n
1989 depends on MMU
1990 depends on m
1991 help
1992 This builds the "test_vmalloc" module that should be used for
1993 stress and performance analysis. So, any new change for vmalloc
1994 subsystem can be evaluated from performance and stability point
1995 of view.
1996
1997 If unsure, say N.
1998
Kees Cook3e2a4c12014-01-23 15:54:38 -08001999config TEST_USER_COPY
2000 tristate "Test user/kernel boundary protections"
Kees Cook3e2a4c12014-01-23 15:54:38 -08002001 depends on m
2002 help
2003 This builds the "test_user_copy" module that runs sanity checks
2004 on the copy_to/from_user infrastructure, making sure basic
2005 user/kernel boundary testing is working. If it fails to load,
2006 a regression has been detected in the user/kernel memory boundary
2007 protections.
2008
2009 If unsure, say N.
2010
Alexei Starovoitov64a89462014-05-08 14:10:52 -07002011config TEST_BPF
2012 tristate "Test BPF filter functionality"
Randy Dunlap98920ba2014-05-13 09:58:44 -07002013 depends on m && NET
Alexei Starovoitov64a89462014-05-08 14:10:52 -07002014 help
2015 This builds the "test_bpf" module that runs various test vectors
2016 against the BPF interpreter or BPF JIT compiler depending on the
2017 current setting. This is in particular useful for BPF JIT compiler
2018 development, but also to run regression tests against changes in
Alexei Starovoitov3c731eb2014-09-26 00:17:07 -07002019 the interpreter code. It also enables test stubs for eBPF maps and
2020 verifier used by user space verifier testsuite.
Alexei Starovoitov64a89462014-05-08 14:10:52 -07002021
2022 If unsure, say N.
2023
Mahesh Bandewar509e56b2019-07-01 14:39:01 -07002024config TEST_BLACKHOLE_DEV
2025 tristate "Test blackhole netdev functionality"
2026 depends on m && NET
2027 help
2028 This builds the "test_blackhole_dev" module that validates the
2029 data path through this blackhole netdev.
2030
2031 If unsure, say N.
2032
Yury Norovdceeb3e2018-02-06 15:38:27 -08002033config FIND_BIT_BENCHMARK
Yury Norov4441fca2017-11-17 15:28:31 -08002034 tristate "Test find_bit functions"
Yury Norov4441fca2017-11-17 15:28:31 -08002035 help
2036 This builds the "test_find_bit" module that measure find_*_bit()
2037 functions performance.
2038
2039 If unsure, say N.
2040
Kees Cook0a8adf52014-07-14 14:38:12 -07002041config TEST_FIRMWARE
2042 tristate "Test firmware loading via userspace interface"
Kees Cook0a8adf52014-07-14 14:38:12 -07002043 depends on FW_LOADER
2044 help
2045 This builds the "test_firmware" module that creates a userspace
2046 interface for testing firmware loading. This can be used to
2047 control the triggering of firmware loading without needing an
2048 actual firmware-using device. The contents can be rechecked by
2049 userspace.
2050
2051 If unsure, say N.
2052
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07002053config TEST_SYSCTL
2054 tristate "sysctl test driver"
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07002055 depends on PROC_SYSCTL
2056 help
2057 This builds the "test_sysctl" module. This driver enables to test the
2058 proc sysctl interfaces available to drivers safely without affecting
2059 production knobs which might alter system functionality.
2060
2061 If unsure, say N.
2062
Iurii Zaikin2cb80db2019-09-23 02:02:47 -07002063config SYSCTL_KUNIT_TEST
Alan Maguirec475c772020-01-06 22:28:20 +00002064 tristate "KUnit test for sysctl"
Iurii Zaikin2cb80db2019-09-23 02:02:47 -07002065 depends on KUNIT
2066 help
2067 This builds the proc sysctl unit test, which runs on boot.
2068 Tests the API contract and implementation correctness of sysctl.
2069 For more information on KUnit and unit tests in general please refer
2070 to the KUnit documentation in Documentation/dev-tools/kunit/.
2071
2072 If unsure, say N.
2073
David Gowea2dd7c2019-10-24 15:46:31 -07002074config LIST_KUNIT_TEST
Alan Maguirec475c772020-01-06 22:28:20 +00002075 tristate "KUnit Test for Kernel Linked-list structures"
David Gowea2dd7c2019-10-24 15:46:31 -07002076 depends on KUNIT
2077 help
2078 This builds the linked list KUnit test suite.
2079 It tests that the API and basic functionality of the list_head type
2080 and associated macros.
2081
2082 KUnit tests run during boot and output the results to the debug log
2083 in TAP format (http://testanything.org/). Only useful for kernel devs
2084 running the KUnit test harness, and not intended for inclusion into a
2085 production build.
2086
2087 For more information on KUnit and unit tests in general please refer
2088 to the KUnit documentation in Documentation/dev-tools/kunit/.
2089
2090 If unsure, say N.
2091
David Rileye704f932014-06-16 14:58:32 -07002092config TEST_UDELAY
2093 tristate "udelay test driver"
David Rileye704f932014-06-16 14:58:32 -07002094 help
2095 This builds the "udelay_test" module that helps to make sure
2096 that udelay() is working properly.
2097
2098 If unsure, say N.
2099
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02002100config TEST_STATIC_KEYS
2101 tristate "Test static keys"
Jason Baron579e1ac2015-07-30 03:59:44 +00002102 depends on m
2103 help
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02002104 Test the static key interfaces.
Jason Baron579e1ac2015-07-30 03:59:44 +00002105
2106 If unsure, say N.
2107
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002108config TEST_KMOD
2109 tristate "kmod stress tester"
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002110 depends on m
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002111 depends on NETDEVICES && NET_CORE && INET # for TUN
YueHaibingae3d6a32019-04-25 22:23:44 -07002112 depends on BLOCK
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002113 select TEST_LKM
2114 select XFS_FS
2115 select TUN
2116 select BTRFS_FS
2117 help
2118 Test the kernel's module loading mechanism: kmod. kmod implements
2119 support to load modules using the Linux kernel's usermode helper.
2120 This test provides a series of tests against kmod.
2121
2122 Although technically you can either build test_kmod as a module or
2123 into the kernel we disallow building it into the kernel since
2124 it stress tests request_module() and this will very likely cause
2125 some issues by taking over precious threads available from other
2126 module load requests, ultimately this could be fatal.
2127
2128 To run tests run:
2129
2130 tools/testing/selftests/kmod/kmod.sh --help
2131
2132 If unsure, say N.
2133
Florian Fainellie4dace32017-09-08 16:15:31 -07002134config TEST_DEBUG_VIRTUAL
2135 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2136 depends on DEBUG_VIRTUAL
2137 help
2138 Test the kernel's ability to detect incorrect calls to
2139 virt_to_phys() done against the non-linear part of the
2140 kernel's virtual address map.
2141
2142 If unsure, say N.
2143
Alexander Shishkince76d932018-10-05 15:43:05 +03002144config TEST_MEMCAT_P
2145 tristate "Test memcat_p() helper function"
2146 help
2147 Test the memcat_p() helper for correctly merging two
2148 pointer arrays together.
2149
2150 If unsure, say N.
2151
Joe Lawrencea2818ee2019-01-09 13:43:29 +01002152config TEST_LIVEPATCH
2153 tristate "Test livepatching"
2154 default n
Joe Lawrencebae05432019-01-31 11:41:24 -05002155 depends on DYNAMIC_DEBUG
Joe Lawrencea2818ee2019-01-09 13:43:29 +01002156 depends on LIVEPATCH
2157 depends on m
2158 help
2159 Test kernel livepatching features for correctness. The tests will
2160 load test modules that will be livepatched in various scenarios.
2161
2162 To run all the livepatching tests:
2163
2164 make -C tools/testing/selftests TARGETS=livepatch run_tests
2165
2166 Alternatively, individual tests may be invoked:
2167
2168 tools/testing/selftests/livepatch/test-callbacks.sh
2169 tools/testing/selftests/livepatch/test-livepatch.sh
2170 tools/testing/selftests/livepatch/test-shadow-vars.sh
2171
2172 If unsure, say N.
2173
Jiri Pirko0a020d42018-11-14 08:22:28 +00002174config TEST_OBJAGG
2175 tristate "Perform selftest on object aggreration manager"
2176 default n
2177 depends on OBJAGG
2178 help
2179 Enable this option to test object aggregation manager on boot
2180 (or module load).
2181
Jiri Pirko0a020d42018-11-14 08:22:28 +00002182
Kees Cook50ceaa95e2019-01-23 12:24:32 -07002183config TEST_STACKINIT
2184 tristate "Test level of stack variable initialization"
2185 help
2186 Test if the kernel is zero-initializing stack variables and
2187 padding. Coverage is controlled by compiler flags,
2188 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2189 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2190
2191 If unsure, say N.
2192
Alexander Potapenko5015a302019-07-16 16:27:27 -07002193config TEST_MEMINIT
2194 tristate "Test heap/page initialization"
2195 help
2196 Test if the kernel is zero-initializing heap and page allocations.
2197 This can be useful to test init_on_alloc and init_on_free features.
2198
2199 If unsure, say N.
2200
Vincent Legolld3deafa2018-02-06 15:38:38 -08002201endif # RUNTIME_TESTING_MENU
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002202
2203config MEMTEST
2204 bool "Memtest"
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002205 ---help---
2206 This option adds a kernel parameter 'memtest', which allows memtest
2207 to be set.
2208 memtest=0, mean disabled; -- default
2209 memtest=1, mean do 1 test pattern;
2210 ...
2211 memtest=17, mean do 17 test patterns.
2212 If you are unsure how to answer this question, answer N.
2213
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002214
Christoph Hellwig06ec64b2018-07-31 13:39:31 +02002215
Branden Bonabyaf9ca6f2019-10-03 17:01:49 -04002216config HYPERV_TESTING
2217 bool "Microsoft Hyper-V driver testing"
2218 default n
2219 depends on HYPERV && DEBUG_FS
2220 help
2221 Select this option to enable Hyper-V vmbus testing.
2222
Changbin Du045f6d72019-12-17 20:51:56 -08002223endmenu # "Kernel Testing and Coverage"
2224
Christoph Hellwig06ec64b2018-07-31 13:39:31 +02002225endmenu # Kernel hacking