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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
269 int "Warn for stack frames larger than (needs gcc 4.4)"
270 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.
279 Requires gcc 4.4
280
Randy Dunlap99657c72009-09-18 12:49:22 -0700281config STRIP_ASM_SYMS
282 bool "Strip assembler-generated symbols during link"
283 default n
284 help
285 Strip internal assembler-generated symbols during a link (symbols
286 that look like '.Lxxx') so they don't pollute the output of
287 get_wchan() and suchlike.
288
Andi Kleen1873e872012-03-28 11:51:18 -0700289config READABLE_ASM
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800290 bool "Generate readable assembler code"
291 depends on DEBUG_KERNEL
Don Mullisbf4735a2006-12-10 02:18:37 -0800292 help
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800293 Disable some compiler optimizations that tend to generate human unreadable
294 assembler output. This may make the kernel slightly slower, but it helps
295 to keep kernel developers who have to stare a lot at assembler listings
296 sane.
Don Mullisbf4735a2006-12-10 02:18:37 -0800297
Masahiro Yamadae949f4c2019-06-04 19:13:59 +0900298config HEADERS_INSTALL
299 bool "Install uapi headers to usr/include"
Don Mullisbf4735a2006-12-10 02:18:37 -0800300 depends on !UML
301 help
Masahiro Yamadae949f4c2019-06-04 19:13:59 +0900302 This option will install uapi headers (headers exported to user-space)
303 into the usr/include directory for use during the kernel build.
304 This is unneeded for building the kernel itself, but needed for some
305 user-space program samples. It is also needed by some features such
306 as uapi header sanity checks.
307
Masahiro Yamada9012d012019-05-14 15:42:25 -0700308config OPTIMIZE_INLINING
Masahiro Yamadaac7c3e42019-09-25 16:47:42 -0700309 def_bool y
Masahiro Yamada9012d012019-05-14 15:42:25 -0700310 help
311 This option determines if the kernel forces gcc to inline the functions
312 developers have marked 'inline'. Doing so takes away freedom from gcc to
313 do what it thinks is best, which is desirable for the gcc 3.x series of
314 compilers. The gcc 4.x series have a rewritten inlining algorithm and
315 enabling this option will generate a smaller kernel there. Hopefully
316 this algorithm is so good that allowing gcc 4.x and above to make the
317 decision will become the default in the future. Until then this option
318 is there to test gcc for this.
319
Sam Ravnborg91341d42008-01-21 21:31:44 +0100320config DEBUG_SECTION_MISMATCH
321 bool "Enable full Section mismatch analysis"
Sam Ravnborg91341d42008-01-21 21:31:44 +0100322 help
323 The section mismatch analysis checks if there are illegal
324 references from one section to another section.
Michael Wittene809ab02011-04-17 04:08:48 +0000325 During linktime or runtime, some sections are dropped;
326 any use of code/data previously in these sections would
Sam Ravnborg91341d42008-01-21 21:31:44 +0100327 most likely result in an oops.
Michael Wittene809ab02011-04-17 04:08:48 +0000328 In the code, functions and variables are annotated with
Paul Gortmaker0db06282013-06-19 14:53:51 -0400329 __init,, etc. (see the full list in include/linux/init.h),
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100330 which results in the code/data being placed in specific sections.
Michael Wittene809ab02011-04-17 04:08:48 +0000331 The section mismatch analysis is always performed after a full
332 kernel build, and enabling this option causes the following
Masahiro Yamadab7dca6d2019-07-17 15:17:57 +0900333 additional step to occur:
Michael Wittene809ab02011-04-17 04:08:48 +0000334 - Add the option -fno-inline-functions-called-once to gcc commands.
335 When inlining a function annotated with __init in a non-init
336 function, we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100337 the analysis would not catch the illegal reference.
Michael Wittene809ab02011-04-17 04:08:48 +0000338 This option tells gcc to inline less (but it does result in
339 a larger kernel).
Sam Ravnborg91341d42008-01-21 21:31:44 +0100340
Nicolas Boichat47490ec2015-10-06 09:44:42 +1030341config SECTION_MISMATCH_WARN_ONLY
342 bool "Make section mismatch errors non-fatal"
343 default y
344 help
345 If you say N here, the build process will fail if there are any
346 section mismatch, instead of just throwing warnings.
347
348 If unsure, say Y.
349
Dave Hansen6dfc0662013-07-01 13:04:46 -0700350#
351# Select this config option from the architecture Kconfig, if it
352# is preferred to always offer frame pointers as a config
353# option on the architecture (regardless of KERNEL_DEBUG):
354#
355config ARCH_WANT_FRAME_POINTERS
356 bool
Dave Hansen6dfc0662013-07-01 13:04:46 -0700357
358config FRAME_POINTER
359 bool "Compile the kernel with frame pointers"
Arnd Bergmanna687a532018-03-07 23:30:54 +0100360 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
Dave Hansen6dfc0662013-07-01 13:04:46 -0700361 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
362 help
363 If you say Y here the resulting kernel image will be slightly
364 larger and slower, but it gives very useful debugging information
365 in case of kernel bugs. (precise oopses/stacktraces/warnings)
366
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600367config STACK_VALIDATION
368 bool "Compile-time stack metadata validation"
369 depends on HAVE_STACK_VALIDATION
370 default n
371 help
372 Add compile-time checks to validate stack metadata, including frame
373 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
374 that runtime stack traces are more reliable.
375
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500376 This is also a prerequisite for generation of ORC unwind data, which
Josh Poimboeuf11af8472017-10-13 15:02:00 -0500377 is needed for CONFIG_UNWINDER_ORC.
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500378
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600379 For more information, see
380 tools/objtool/Documentation/stack-validation.txt.
381
Dave Hansen6dfc0662013-07-01 13:04:46 -0700382config DEBUG_FORCE_WEAK_PER_CPU
383 bool "Force weak per-cpu definitions"
384 depends on DEBUG_KERNEL
385 help
386 s390 and alpha require percpu variables in modules to be
387 defined weak to work around addressing range issue which
388 puts the following two restrictions on percpu variable
389 definitions.
390
391 1. percpu symbols must be unique whether static or not
392 2. percpu variables can't be defined inside a function
393
394 To ensure that generic code follows the above rules, this
395 option forces all percpu variables to be defined as weak.
396
397endmenu # "Compiler options"
398
Changbin Du6210b642019-12-06 17:03:42 -0800399menu "Generic Kernel Debugging Instruments"
400
Dave Hansen6dfc0662013-07-01 13:04:46 -0700401config MAGIC_SYSRQ
402 bool "Magic SysRq key"
403 depends on !UML
404 help
405 If you say Y here, you will have some control over the system even
406 if the system crashes for example during kernel debugging (e.g., you
407 will be able to flush the buffer cache to disk, reboot the system
408 immediately or dump some status information). This is accomplished
409 by pressing various keys while holding SysRq (Alt+PrintScreen). It
410 also works on a serial console (on PC hardware at least), if you
411 send a BREAK and then within 5 seconds a command keypress. The
Hans Holmbergf8998c22017-03-16 09:37:32 +0100412 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
413 Don't say Y unless you really know what this hack does.
Dave Hansen6dfc0662013-07-01 13:04:46 -0700414
Ben Hutchings8eaede42013-10-07 01:05:46 +0100415config MAGIC_SYSRQ_DEFAULT_ENABLE
416 hex "Enable magic SysRq key functions by default"
417 depends on MAGIC_SYSRQ
418 default 0x1
419 help
420 Specifies which SysRq key functions are enabled by default.
421 This may be set to 1 or 0 to enable or disable them all, or
Hans Holmbergf8998c22017-03-16 09:37:32 +0100422 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
Ben Hutchings8eaede42013-10-07 01:05:46 +0100423
Felix Fietkau732dbf32016-12-22 08:31:34 +0100424config MAGIC_SYSRQ_SERIAL
425 bool "Enable magic SysRq key over serial"
426 depends on MAGIC_SYSRQ
427 default y
428 help
429 Many embedded boards have a disconnected TTL level serial which can
430 generate some garbage that can lead to spurious false sysrq detects.
431 This option allows you to decide whether you want to enable the
432 magic SysRq key.
433
Changbin Duec29a5c2019-12-06 17:04:06 -0800434config DEBUG_FS
435 bool "Debug Filesystem"
436 help
437 debugfs is a virtual file system that kernel developers use to put
438 debugging files into. Enable this option to be able to read and
439 write to these files.
440
441 For detailed documentation on the debugfs API, see
442 Documentation/filesystems/.
443
444 If unsure, say N.
445
Changbin Du6210b642019-12-06 17:03:42 -0800446source "lib/Kconfig.kgdb"
447
448source "lib/Kconfig.ubsan"
449
450endmenu
451
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800452config DEBUG_KERNEL
453 bool "Kernel debugging"
454 help
455 Say Y here if you are developing drivers or trying to debug and
456 identify kernel problems.
457
Sinan Kayac66d7a22019-05-14 15:44:00 -0700458config DEBUG_MISC
459 bool "Miscellaneous debug code"
460 default DEBUG_KERNEL
461 depends on DEBUG_KERNEL
462 help
463 Say Y here if you need to enable miscellaneous debug code that should
464 be under a more specific debug option but isn't.
465
466
Dave Hansen0610c8a2013-07-01 13:04:43 -0700467menu "Memory Debugging"
David Woodhousea304e1b2007-02-12 00:52:00 -0800468
Masahiro Yamada8636a1f2018-12-11 20:01:04 +0900469source "mm/Kconfig.debug"
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800470
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700471config DEBUG_OBJECTS
472 bool "Debug object operations"
473 depends on DEBUG_KERNEL
474 help
475 If you say Y here, additional code will be inserted into the
476 kernel to track the life time of various objects and validate
477 the operations on those objects.
478
479config DEBUG_OBJECTS_SELFTEST
480 bool "Debug objects selftest"
481 depends on DEBUG_OBJECTS
482 help
483 This enables the selftest of the object debug code.
484
485config DEBUG_OBJECTS_FREE
486 bool "Debug objects in freed memory"
487 depends on DEBUG_OBJECTS
488 help
489 This enables checks whether a k/v free operation frees an area
490 which contains an object which has not been deactivated
491 properly. This can make kmalloc/kfree-intensive workloads
492 much slower.
493
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700494config DEBUG_OBJECTS_TIMERS
495 bool "Debug timer objects"
496 depends on DEBUG_OBJECTS
497 help
498 If you say Y here, additional code will be inserted into the
499 timer routines to track the life time of timer objects and
500 validate the timer operations.
501
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900502config DEBUG_OBJECTS_WORK
503 bool "Debug work objects"
504 depends on DEBUG_OBJECTS
505 help
506 If you say Y here, additional code will be inserted into the
507 work queue routines to track the life time of work objects and
508 validate the work operations.
509
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400510config DEBUG_OBJECTS_RCU_HEAD
511 bool "Debug RCU callbacks objects"
Mathieu Desnoyersfc2ecf72011-02-23 09:42:14 -0800512 depends on DEBUG_OBJECTS
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400513 help
514 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
515
Tejun Heoe2852ae2010-10-26 14:23:05 -0700516config DEBUG_OBJECTS_PERCPU_COUNTER
517 bool "Debug percpu counter objects"
518 depends on DEBUG_OBJECTS
519 help
520 If you say Y here, additional code will be inserted into the
521 percpu counter routines to track the life time of percpu counter
522 objects and validate the percpu counter operations.
523
Ingo Molnar3ae70202008-11-26 10:02:00 +0100524config DEBUG_OBJECTS_ENABLE_DEFAULT
525 int "debug_objects bootup default value (0-1)"
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800526 range 0 1
527 default "1"
528 depends on DEBUG_OBJECTS
529 help
530 Debug objects boot parameter default value
Ingo Molnar3ae70202008-11-26 10:02:00 +0100531
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800533 bool "Debug slab memory allocations"
Levin, Alexander (Sasha Levin)4675ff02017-11-15 17:36:02 -0800534 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 help
536 Say Y here to have the kernel do limited verification on memory
537 allocation as well as poisoning memory on free to catch use of freed
538 memory. This can make kmalloc/kfree-intensive workloads much slower.
539
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700540config SLUB_DEBUG_ON
541 bool "SLUB debugging on by default"
Levin, Alexander (Sasha Levin)4675ff02017-11-15 17:36:02 -0800542 depends on SLUB && SLUB_DEBUG
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700543 default n
544 help
545 Boot with debugging on by default. SLUB boots by default with
546 the runtime debug capabilities switched off. Enabling this is
547 equivalent to specifying the "slub_debug" parameter on boot.
548 There is no support for more fine grained debug control like
549 possible with slub_debug=xxx. SLUB debugging may be switched
550 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
551 "slub_debug=-".
552
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800553config SLUB_STATS
554 default n
555 bool "Enable SLUB performance statistics"
Christoph Lameterab4d5ed2010-10-05 13:57:26 -0500556 depends on SLUB && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800557 help
558 SLUB statistics are useful to debug SLUBs allocation behavior in
559 order find ways to optimize the allocator. This should never be
560 enabled for production use since keeping statistics slows down
561 the allocator by a few percentage points. The slabinfo command
562 supports the determination of the most active slabs to figure
563 out which slabs are relevant to a particular load.
564 Try running: slabinfo -DA
565
Catalin Marinasb69ec422012-10-08 16:28:11 -0700566config HAVE_DEBUG_KMEMLEAK
567 bool
568
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100569config DEBUG_KMEMLEAK
570 bool "Kernel memory leak detector"
Kees Cook525c1f92013-01-16 18:54:16 -0800571 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
Catalin Marinas79e0d9b2011-04-27 17:06:19 +0100572 select DEBUG_FS
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100573 select STACKTRACE if STACKTRACE_SUPPORT
574 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800575 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100576 help
577 Say Y here if you want to enable the memory leak
578 detector. The memory allocation/freeing is traced in a way
579 similar to the Boehm's conservative garbage collector, the
580 difference being that the orphan objects are not freed but
581 only shown in /sys/kernel/debug/kmemleak. Enabling this
582 feature will introduce an overhead to memory
Andreas Platschek700199b02016-12-14 15:05:40 -0800583 allocations. See Documentation/dev-tools/kmemleak.rst for more
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100584 details.
585
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100586 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
587 of finding leaks due to the slab objects poisoning.
588
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100589 In order to access the kmemleak file, debugfs needs to be
590 mounted (usually at /sys/kernel/debug).
591
Catalin Marinasc5665862019-09-23 15:34:05 -0700592config DEBUG_KMEMLEAK_MEM_POOL_SIZE
593 int "Kmemleak memory pool size"
Catalin Marinasa9d90582009-06-25 10:16:11 +0100594 depends on DEBUG_KMEMLEAK
Qian Caic59180a2019-09-23 15:34:10 -0700595 range 200 1000000
Nicolas Boichatb751c522019-09-23 15:33:55 -0700596 default 16000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100597 help
598 Kmemleak must track all the memory allocations to avoid
599 reporting false positives. Since memory may be allocated or
Catalin Marinasc5665862019-09-23 15:34:05 -0700600 freed before kmemleak is fully initialised, use a static pool
601 of metadata objects to track such callbacks. After kmemleak is
602 fully initialised, this memory pool acts as an emergency one
603 if slab allocations fail.
Catalin Marinasa9d90582009-06-25 10:16:11 +0100604
Catalin Marinas0822ee42009-06-11 13:24:14 +0100605config DEBUG_KMEMLEAK_TEST
606 tristate "Simple test for the kernel memory leak detector"
Daniel Baluta97182692011-04-04 15:06:44 -0700607 depends on DEBUG_KMEMLEAK && m
Catalin Marinas0822ee42009-06-11 13:24:14 +0100608 help
Daniel Baluta97182692011-04-04 15:06:44 -0700609 This option enables a module that explicitly leaks memory.
Catalin Marinas0822ee42009-06-11 13:24:14 +0100610
611 If unsure, say N.
612
Jason Baronab0155a2010-07-19 11:54:17 +0100613config DEBUG_KMEMLEAK_DEFAULT_OFF
614 bool "Default kmemleak to off"
615 depends on DEBUG_KMEMLEAK
616 help
617 Say Y here to disable kmemleak by default. It can then be enabled
618 on the command line via kmemleak=on.
619
Sri Krishna chowdaryd53ce042018-12-28 00:38:54 -0800620config DEBUG_KMEMLEAK_AUTO_SCAN
621 bool "Enable kmemleak auto scan thread on boot up"
622 default y
623 depends on DEBUG_KMEMLEAK
624 help
625 Depending on the cpu, kmemleak scan may be cpu intensive and can
626 stall user tasks at times. This option enables/disables automatic
627 kmemleak scan at boot up.
628
629 Say N here to disable kmemleak auto scan thread to stop automatic
630 scanning. Disabling this option disables automatic reporting of
631 memory leaks.
632
633 If unsure, say Y.
634
Dave Hansen0610c8a2013-07-01 13:04:43 -0700635config DEBUG_STACK_USAGE
636 bool "Stack utilization instrumentation"
Helge Deller6c31da32016-03-19 17:54:10 +0100637 depends on DEBUG_KERNEL && !IA64
Dave Hansen0610c8a2013-07-01 13:04:43 -0700638 help
639 Enables the display of the minimum amount of free stack which each
640 task has ever had available in the sysrq-T and sysrq-P debug output.
641
642 This option will slow down process creation somewhat.
643
Changbin Dudc9b9632019-12-06 17:03:57 -0800644config SCHED_STACK_END_CHECK
645 bool "Detect stack corruption on calls to schedule()"
646 depends on DEBUG_KERNEL
647 default n
648 help
649 This option checks for a stack overrun on calls to schedule().
650 If the stack end location is found to be over written always panic as
651 the content of the corrupted region can no longer be trusted.
652 This is to ensure no erroneous behaviour occurs which could result in
653 data corruption or a sporadic crash at a later stage once the region
654 is examined. The runtime overhead introduced is minimal.
655
Dave Hansen0610c8a2013-07-01 13:04:43 -0700656config DEBUG_VM
657 bool "Debug VM"
658 depends on DEBUG_KERNEL
659 help
660 Enable this to turn on extended checks in the virtual-memory system
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800661 that may impact performance.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700662
663 If unsure, say N.
664
Davidlohr Bueso4f115142014-06-04 16:06:46 -0700665config DEBUG_VM_VMACACHE
666 bool "Debug VMA caching"
667 depends on DEBUG_VM
668 help
669 Enable this to turn on VMA caching debug information. Doing so
670 can cause significant overhead, so only enable it in non-production
671 environments.
672
673 If unsure, say N.
674
Dave Hansen0610c8a2013-07-01 13:04:43 -0700675config DEBUG_VM_RB
676 bool "Debug VM red-black trees"
677 depends on DEBUG_VM
678 help
Davidlohr Buesoa663dad2014-04-18 15:07:22 -0700679 Enable VM red-black tree debugging information and extra validations.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700680
681 If unsure, say N.
682
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800683config DEBUG_VM_PGFLAGS
684 bool "Debug page-flags operations"
685 depends on DEBUG_VM
686 help
687 Enables extra validation on page flags operations.
688
689 If unsure, say N.
690
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800691config ARCH_HAS_DEBUG_VIRTUAL
692 bool
693
Dave Hansen0610c8a2013-07-01 13:04:43 -0700694config DEBUG_VIRTUAL
695 bool "Debug VM translations"
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800696 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
Dave Hansen0610c8a2013-07-01 13:04:43 -0700697 help
698 Enable some costly sanity checks in virtual to page code. This can
699 catch mistakes with virt_to_page() and friends.
700
701 If unsure, say N.
702
703config DEBUG_NOMMU_REGIONS
704 bool "Debug the global anon/private NOMMU mapping region tree"
705 depends on DEBUG_KERNEL && !MMU
706 help
707 This option causes the global tree of anonymous and private mapping
708 regions to be regularly checked for invalid topology.
709
710config DEBUG_MEMORY_INIT
711 bool "Debug memory initialisation" if EXPERT
712 default !EXPERT
713 help
714 Enable this for additional checks during memory initialisation.
715 The sanity checks verify aspects of the VM such as the memory model
716 and other information provided by the architecture. Verbose
717 information will be printed at KERN_DEBUG loglevel depending
718 on the mminit_loglevel= command-line option.
719
720 If unsure, say Y
721
722config MEMORY_NOTIFIER_ERROR_INJECT
723 tristate "Memory hotplug notifier error injection module"
724 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
725 help
726 This option provides the ability to inject artificial errors to
727 memory hotplug notifier chain callbacks. It is controlled through
728 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
729
730 If the notifier call chain should be failed with some events
731 notified, write the error code to "actions/<notifier event>/error".
732
733 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
734
735 # cd /sys/kernel/debug/notifier-error-inject/memory
736 # echo -12 > actions/MEM_GOING_OFFLINE/error
737 # echo offline > /sys/devices/system/memory/memoryXXX/state
738 bash: echo: write error: Cannot allocate memory
739
740 To compile this code as a module, choose M here: the module will
741 be called memory-notifier-error-inject.
742
743 If unsure, say N.
744
745config DEBUG_PER_CPU_MAPS
746 bool "Debug access to per_cpu maps"
747 depends on DEBUG_KERNEL
748 depends on SMP
749 help
750 Say Y to verify that the per_cpu map being accessed has
751 been set up. This adds a fair amount of code to kernel memory
752 and decreases performance.
753
754 Say N if unsure.
755
756config DEBUG_HIGHMEM
757 bool "Highmem debugging"
758 depends on DEBUG_KERNEL && HIGHMEM
759 help
Geert Uytterhoevenb1357c92014-04-14 18:55:50 +0200760 This option enables additional error checking for high memory
761 systems. Disable for production systems.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700762
763config HAVE_DEBUG_STACKOVERFLOW
764 bool
765
766config DEBUG_STACKOVERFLOW
767 bool "Check for stack overflows"
768 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
769 ---help---
770 Say Y here if you want to check for overflows of kernel, IRQ
Borislav Petkovedb0ec02015-01-25 19:50:34 +0100771 and exception stacks (if your architecture uses them). This
Dave Hansen0610c8a2013-07-01 13:04:43 -0700772 option will show detailed messages if free stack space drops
773 below a certain limit.
774
775 These kinds of bugs usually occur when call-chains in the
776 kernel get too deep, especially when interrupts are
777 involved.
778
779 Use this in cases where you see apparently random memory
780 corruption, especially if it appears in 'struct thread_info'
781
782 If in doubt, say "N".
783
Andrey Ryabinin0b24bec2015-02-13 14:39:17 -0800784source "lib/Kconfig.kasan"
785
Dave Hansen0610c8a2013-07-01 13:04:43 -0700786endmenu # "Memory Debugging"
787
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788config DEBUG_SHIRQ
789 bool "Debug shared IRQ handlers"
Martin Schwidefsky0244ad02013-08-30 09:39:53 +0200790 depends on DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791 help
792 Enable this to generate a spurious interrupt as soon as a shared
793 interrupt handler is registered, and just before one is deregistered.
794 Drivers ought to be able to handle interrupts coming in at those
795 points; some don't and need to be caught.
796
Changbin Duf43a2892019-12-06 17:03:54 -0800797menu "Debug Oops, Lockups and Hangs"
798
799config PANIC_ON_OOPS
800 bool "Panic on Oops"
801 help
802 Say Y here to enable the kernel to panic when it oopses. This
803 has the same effect as setting oops=panic on the kernel command
804 line.
805
806 This feature is useful to ensure that the kernel does not do
807 anything erroneous after an oops which could result in data
808 corruption or other issues.
809
810 Say N if unsure.
811
812config PANIC_ON_OOPS_VALUE
813 int
814 range 0 1
815 default 0 if !PANIC_ON_OOPS
816 default 1 if PANIC_ON_OOPS
817
818config PANIC_TIMEOUT
819 int "panic timeout"
820 default 0
821 help
822 Set the timeout value (in seconds) until a reboot occurs when the
823 the kernel panics. If n = 0, then we wait forever. A timeout
824 value n > 0 will wait n seconds before rebooting, while a timeout
825 value n < 0 will reboot immediately.
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700826
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827config LOCKUP_DETECTOR
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700828 bool
829
830config SOFTLOCKUP_DETECTOR
831 bool "Detect Soft Lockups"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 depends on DEBUG_KERNEL && !S390
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700833 select LOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 help
835 Say Y here to enable the kernel to act as a watchdog to detect
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700836 soft lockups.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837
838 Softlockups are bugs that cause the kernel to loop in kernel
839 mode for more than 20 seconds, without giving other tasks a
840 chance to run. The current stack trace is displayed upon
841 detection and the system will stay locked up.
842
Randy Dunlap5f00ae02018-04-10 16:32:51 -0700843config BOOTPARAM_SOFTLOCKUP_PANIC
844 bool "Panic (Reboot) On Soft Lockups"
845 depends on SOFTLOCKUP_DETECTOR
846 help
847 Say Y here to enable the kernel to panic on "soft lockups",
848 which are bugs that cause the kernel to loop in kernel
849 mode for more than 20 seconds (configurable using the watchdog_thresh
850 sysctl), without giving other tasks a chance to run.
851
852 The panic can be used in combination with panic_timeout,
853 to cause the system to reboot automatically after a
854 lockup has been detected. This feature is useful for
855 high-availability systems that have uptime guarantees and
856 where a lockup must be resolved ASAP.
857
858 Say N if unsure.
859
860config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
861 int
862 depends on SOFTLOCKUP_DETECTOR
863 range 0 1
864 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
865 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
866
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700867config HARDLOCKUP_DETECTOR_PERF
868 bool
869 select SOFTLOCKUP_DETECTOR
870
871#
Thomas Gleixner7edaeb62017-08-15 09:50:13 +0200872# Enables a timestamp based low pass filter to compensate for perf based
873# hard lockup detection which runs too fast due to turbo modes.
874#
875config HARDLOCKUP_CHECK_TIMESTAMP
876 bool
877
878#
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700879# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
880# lockup detector rather than the perf based detector.
881#
882config HARDLOCKUP_DETECTOR
883 bool "Detect Hard Lockups"
884 depends on DEBUG_KERNEL && !S390
885 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
886 select LOCKUP_DETECTOR
887 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
888 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
889 help
890 Say Y here to enable the kernel to act as a watchdog to detect
891 hard lockups.
892
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893 Hardlockups are bugs that cause the CPU to loop in kernel mode
894 for more than 10 seconds, without letting other interrupts have a
895 chance to run. The current stack trace is displayed upon detection
896 and the system will stay locked up.
897
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898config BOOTPARAM_HARDLOCKUP_PANIC
899 bool "Panic (Reboot) On Hard Lockups"
900 depends on HARDLOCKUP_DETECTOR
901 help
902 Say Y here to enable the kernel to panic on "hard lockups",
903 which are bugs that cause the kernel to loop in kernel
904 mode with interrupts disabled for more than 10 seconds (configurable
905 using the watchdog_thresh sysctl).
906
907 Say N if unsure.
908
909config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
910 int
911 depends on HARDLOCKUP_DETECTOR
912 range 0 1
913 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
914 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
915
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916config DETECT_HUNG_TASK
917 bool "Detect Hung Tasks"
918 depends on DEBUG_KERNEL
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700919 default SOFTLOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920 help
921 Say Y here to enable the kernel to detect "hung tasks",
922 which are bugs that cause the task to be stuck in
Vivien Didelot96b03ab2016-09-22 16:55:13 -0400923 uninterruptible "D" state indefinitely.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924
925 When a hung task is detected, the kernel will print the
926 current stack trace (which you should report), but the
927 task will stay in uninterruptible state. If lockdep is
928 enabled then all held locks will also be reported. This
929 feature has negligible overhead.
Al Viro871751e2006-03-25 03:06:39 -0800930
931config DEFAULT_HUNG_TASK_TIMEOUT
932 int "Default timeout for hung task detection (in seconds)"
933 depends on DETECT_HUNG_TASK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934 default 120
935 help
Ingo Molnar8637c092006-07-03 00:24:38 -0700936 This option controls the default timeout (in seconds) used
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937 to determine when a task has become non-responsive and should
938 be considered hung.
939
940 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
941 sysctl or by writing a value to
942 /proc/sys/kernel/hung_task_timeout_secs.
943
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700944 A timeout of 0 disables the check. The default is two minutes.
945 Keeping the default should be fine in most cases.
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700946
947config BOOTPARAM_HUNG_TASK_PANIC
948 bool "Panic (Reboot) On Hung Tasks"
949 depends on DETECT_HUNG_TASK
950 help
951 Say Y here to enable the kernel to panic on "hung tasks",
952 which are bugs that cause the kernel to leave a task stuck
953 in uninterruptible "D" state.
954
955 The panic can be used in combination with panic_timeout,
Thomas Gleixner61a87122006-06-27 02:54:56 -0700956 to cause the system to reboot automatically after a
957 hung task has been detected. This feature is useful for
Roman Zippela1583d32006-06-27 02:55:00 -0700958 high-availability systems that have uptime guarantees and
Thomas Gleixner61a87122006-06-27 02:54:56 -0700959 where a hung tasks must be resolved ASAP.
960
961 Say N if unsure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100963config BOOTPARAM_HUNG_TASK_PANIC_VALUE
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 int
965 depends on DETECT_HUNG_TASK
966 range 0 1
967 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
968 default 1 if BOOTPARAM_HUNG_TASK_PANIC
969
Tejun Heo82607adc2015-12-08 11:28:04 -0500970config WQ_WATCHDOG
971 bool "Detect Workqueue Stalls"
972 depends on DEBUG_KERNEL
973 help
974 Say Y here to enable stall detection on workqueues. If a
975 worker pool doesn't make forward progress on a pending work
976 item for over a given amount of time, 30s by default, a
977 warning message is printed along with dump of workqueue
978 state. This can be configured through kernel parameter
979 "workqueue.watchdog_thresh" and its sysfs counterpart.
980
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700981endmenu # "Debug lockups and hangs"
982
Changbin Duebebdd02019-12-06 17:04:00 -0800983menu "Scheduler Debugging"
Jason Baron5800dc32013-11-25 23:23:04 +0000984
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985config SCHED_DEBUG
986 bool "Collect scheduler debugging info"
987 depends on DEBUG_KERNEL && PROC_FS
988 default y
989 help
990 If you say Y here, the /proc/sched_debug file will be provided
991 that can help debug the scheduler. The runtime overhead of this
992 option is minimal.
993
Naveen N. Raof6db8342015-06-25 23:53:37 +0530994config SCHED_INFO
995 bool
996 default n
997
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998config SCHEDSTATS
999 bool "Collect scheduler statistics"
1000 depends on DEBUG_KERNEL && PROC_FS
Naveen N. Raof6db8342015-06-25 23:53:37 +05301001 select SCHED_INFO
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002 help
1003 If you say Y here, additional code will be inserted into the
1004 scheduler and related routines to collect statistics about
1005 scheduler behavior and provide them in /proc/schedstat. These
1006 stats may be useful for both tuning and debugging the scheduler
1007 If you aren't debugging the scheduler or trying to tune a specific
1008 application, you can say N to avoid the very slight overhead
1009 this adds.
1010
Changbin Duebebdd02019-12-06 17:04:00 -08001011endmenu
Aaron Tomlin0d9e2632014-09-12 14:16:19 +01001012
John Stultz3c17ad12015-03-11 21:16:32 -07001013config DEBUG_TIMEKEEPING
1014 bool "Enable extra timekeeping sanity checking"
1015 help
1016 This option will enable additional timekeeping sanity checks
1017 which may be helpful when diagnosing issues where timekeeping
1018 problems are suspected.
1019
1020 This may include checks in the timekeeping hotpaths, so this
1021 option may have a (very small) performance impact to some
1022 workloads.
1023
1024 If unsure, say N.
1025
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026config DEBUG_PREEMPT
1027 bool "Debug preemptible kernel"
Sebastian Andrzej Siewior9f472862019-10-15 21:18:19 +02001028 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001029 default y
1030 help
1031 If you say Y here then the kernel will use a debug variant of the
1032 commonly used smp_processor_id() function and will print warnings
1033 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1034 will detect preemption count underflows.
1035
Dave Hansen9eade162013-07-01 13:04:47 -07001036menu "Lock Debugging (spinlocks, mutexes, etc...)"
1037
Waiman Longf07cbeb2018-03-30 17:27:59 -04001038config LOCK_DEBUGGING_SUPPORT
1039 bool
1040 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1041 default y
1042
Waiman Long19193bc2018-03-30 17:28:00 -04001043config PROVE_LOCKING
1044 bool "Lock debugging: prove locking correctness"
1045 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1046 select LOCKDEP
1047 select DEBUG_SPINLOCK
1048 select DEBUG_MUTEXES
1049 select DEBUG_RT_MUTEXES if RT_MUTEXES
Waiman Longc71fd892019-05-20 16:59:00 -04001050 select DEBUG_RWSEMS
Waiman Long19193bc2018-03-30 17:28:00 -04001051 select DEBUG_WW_MUTEX_SLOWPATH
1052 select DEBUG_LOCK_ALLOC
1053 select TRACE_IRQFLAGS
1054 default n
1055 help
1056 This feature enables the kernel to prove that all locking
1057 that occurs in the kernel runtime is mathematically
1058 correct: that under no circumstance could an arbitrary (and
1059 not yet triggered) combination of observed locking
1060 sequences (on an arbitrary number of CPUs, running an
1061 arbitrary number of tasks and interrupt contexts) cause a
1062 deadlock.
1063
1064 In short, this feature enables the kernel to report locking
1065 related deadlocks before they actually occur.
1066
1067 The proof does not depend on how hard and complex a
1068 deadlock scenario would be to trigger: how many
1069 participant CPUs, tasks and irq-contexts would be needed
1070 for it to trigger. The proof also does not depend on
1071 timing: if a race and a resulting deadlock is possible
1072 theoretically (no matter how unlikely the race scenario
1073 is), it will be proven so and will immediately be
1074 reported by the kernel (once the event is observed that
1075 makes the deadlock theoretically possible).
1076
1077 If a deadlock is impossible (i.e. the locking rules, as
1078 observed by the kernel, are mathematically correct), the
1079 kernel reports nothing.
1080
1081 NOTE: this feature can also be enabled for rwlocks, mutexes
1082 and rwsems - in which case all dependencies between these
1083 different locking variants are observed and mapped too, and
1084 the proof of observed correctness is also maintained for an
1085 arbitrary combination of these separate locking variants.
1086
Mauro Carvalho Chehab387b1462019-04-10 08:32:41 -03001087 For more details, see Documentation/locking/lockdep-design.rst.
Waiman Long19193bc2018-03-30 17:28:00 -04001088
1089config LOCK_STAT
1090 bool "Lock usage statistics"
1091 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1092 select LOCKDEP
1093 select DEBUG_SPINLOCK
1094 select DEBUG_MUTEXES
1095 select DEBUG_RT_MUTEXES if RT_MUTEXES
1096 select DEBUG_LOCK_ALLOC
1097 default n
1098 help
1099 This feature enables tracking lock contention points
1100
Mauro Carvalho Chehab387b1462019-04-10 08:32:41 -03001101 For more details, see Documentation/locking/lockstat.rst
Waiman Long19193bc2018-03-30 17:28:00 -04001102
1103 This also enables lock events required by "perf lock",
1104 subcommand of perf.
1105 If you want to use "perf lock", you also need to turn on
1106 CONFIG_EVENT_TRACING.
1107
1108 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1109 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1110
Linus Torvalds1da177e2005-04-16 15:20:36 -07001111config DEBUG_RT_MUTEXES
1112 bool "RT Mutex debugging, deadlock detection"
1113 depends on DEBUG_KERNEL && RT_MUTEXES
1114 help
1115 This allows rt mutex semantics violations and rt mutex related
1116 deadlocks (lockups) to be detected and reported automatically.
1117
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001119 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001120 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +05301121 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -07001122 help
1123 Say Y here and build SMP to catch missing spinlock initialization
1124 and certain other kinds of spinlock errors commonly made. This is
1125 best used in conjunction with the NMI watchdog so that spinlock
1126 deadlocks are also debuggable.
1127
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001128config DEBUG_MUTEXES
1129 bool "Mutex debugging: basic checks"
1130 depends on DEBUG_KERNEL
1131 help
1132 This feature allows mutex semantics violations to be detected and
1133 reported.
1134
Daniel Vetter23010022013-06-20 13:31:17 +02001135config DEBUG_WW_MUTEX_SLOWPATH
1136 bool "Wait/wound mutex debugging: Slowpath testing"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001137 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Daniel Vetter23010022013-06-20 13:31:17 +02001138 select DEBUG_LOCK_ALLOC
1139 select DEBUG_SPINLOCK
1140 select DEBUG_MUTEXES
1141 help
1142 This feature enables slowpath testing for w/w mutex users by
1143 injecting additional -EDEADLK wound/backoff cases. Together with
1144 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1145 will test all possible w/w mutex interface abuse with the
1146 exception of simply not acquiring all the required locks.
Rob Clark4d692372014-08-27 11:19:26 -04001147 Note that this feature can introduce significant overhead, so
1148 it really should not be enabled in a production or distro kernel,
1149 even a debug kernel. If you are a driver writer, enable it. If
1150 you are a distro, do not.
Daniel Vetter23010022013-06-20 13:31:17 +02001151
Waiman Long5149cba2018-03-30 17:27:58 -04001152config DEBUG_RWSEMS
1153 bool "RW Semaphore debugging: basic checks"
Waiman Longc71fd892019-05-20 16:59:00 -04001154 depends on DEBUG_KERNEL
Waiman Long5149cba2018-03-30 17:27:58 -04001155 help
Waiman Longc71fd892019-05-20 16:59:00 -04001156 This debugging feature allows mismatched rw semaphore locks
1157 and unlocks to be detected and reported.
Waiman Long5149cba2018-03-30 17:27:58 -04001158
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001159config DEBUG_LOCK_ALLOC
1160 bool "Lock debugging: detect incorrect freeing of live locks"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001161 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001162 select DEBUG_SPINLOCK
1163 select DEBUG_MUTEXES
Peter Zijlstraf5694782016-09-19 12:15:37 +02001164 select DEBUG_RT_MUTEXES if RT_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001165 select LOCKDEP
1166 help
1167 This feature will check whether any held lock (spinlock, rwlock,
1168 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1169 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1170 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1171 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1172 held during task exit.
1173
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001174config LOCKDEP
1175 bool
Waiman Longf07cbeb2018-03-30 17:27:59 -04001176 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001177 select STACKTRACE
Stefan Agnerf9b58e82018-09-30 23:02:33 +01001178 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001179 select KALLSYMS
1180 select KALLSYMS_ALL
1181
Daniel Jordan395102d2017-04-10 11:50:52 -04001182config LOCKDEP_SMALL
1183 bool
1184
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001185config DEBUG_LOCKDEP
1186 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -07001187 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001188 help
1189 If you say Y here, the lock dependency engine will do
1190 additional runtime checks to debug itself, at the price
1191 of more runtime overhead.
1192
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001193config DEBUG_ATOMIC_SLEEP
1194 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +02001195 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001196 depends on DEBUG_KERNEL
Christoph Hellwig87a4c372018-07-31 13:39:32 +02001197 depends on !ARCH_NO_PREEMPT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198 help
1199 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001200 noisy if they are called inside atomic sections: when a spinlock is
1201 held, inside an rcu read side critical section, inside preempt disabled
1202 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203
Ingo Molnarcae2ed92006-07-03 00:24:48 -07001204config DEBUG_LOCKING_API_SELFTESTS
1205 bool "Locking API boot-time self-tests"
1206 depends on DEBUG_KERNEL
1207 help
1208 Say Y here if you want the kernel to run a short self-test during
1209 bootup. The self-test checks whether common types of locking bugs
1210 are detected by debugging mechanisms or not. (if you disable
1211 lock debugging then those bugs wont be detected of course.)
1212 The following locking APIs are covered: spinlocks, rwlocks,
1213 mutexes and rwsems.
1214
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001215config LOCK_TORTURE_TEST
1216 tristate "torture tests for locking"
1217 depends on DEBUG_KERNEL
1218 select TORTURE_TEST
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001219 help
1220 This option provides a kernel module that runs torture tests
1221 on kernel locking primitives. The kernel module may be built
1222 after the fact on the running kernel to be tested, if desired.
1223
1224 Say Y here if you want kernel locking-primitive torture tests
1225 to be built into the kernel.
1226 Say M if you want these torture tests to build as a module.
1227 Say N if you are unsure.
1228
Chris Wilsonf2a5fec2016-12-01 11:47:06 +00001229config WW_MUTEX_SELFTEST
1230 tristate "Wait/wound mutex selftests"
1231 help
1232 This option provides a kernel module that runs tests on the
1233 on the struct ww_mutex locking API.
1234
1235 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1236 with this test harness.
1237
1238 Say M if you want these self tests to build as a module.
1239 Say N if you are unsure.
1240
Dave Hansen9eade162013-07-01 13:04:47 -07001241endmenu # lock debugging
1242
1243config TRACE_IRQFLAGS
1244 bool
1245 help
1246 Enables hooks to interrupt enabling and disabling for
1247 either tracing or lock debugging.
1248
Ingo Molnar8637c092006-07-03 00:24:38 -07001249config STACKTRACE
Dave Jones0c38e1f2014-08-29 15:18:35 -07001250 bool "Stack backtrace support"
Ingo Molnar8637c092006-07-03 00:24:38 -07001251 depends on STACKTRACE_SUPPORT
Dave Jones0c38e1f2014-08-29 15:18:35 -07001252 help
1253 This option causes the kernel to create a /proc/pid/stack for
1254 every process, showing its current stack trace.
1255 It is also used by various kernel debugging features that require
1256 stack trace generation.
Ingo Molnar8637c092006-07-03 00:24:38 -07001257
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001258config WARN_ALL_UNSEEDED_RANDOM
1259 bool "Warn for all uses of unseeded randomness"
1260 default n
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001261 help
1262 Some parts of the kernel contain bugs relating to their use of
1263 cryptographically secure random numbers before it's actually possible
1264 to generate those numbers securely. This setting ensures that these
1265 flaws don't go unnoticed, by enabling a message, should this ever
1266 occur. This will allow people with obscure setups to know when things
1267 are going wrong, so that they might contact developers about fixing
1268 it.
1269
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001270 Unfortunately, on some models of some architectures getting
1271 a fully seeded CRNG is extremely difficult, and so this can
1272 result in dmesg getting spammed for a surprisingly long
1273 time. This is really bad from a security perspective, and
1274 so architecture maintainers really need to do what they can
1275 to get the CRNG seeded sooner after the system is booted.
Thibaut Sautereau4c5d1142018-09-04 15:46:23 -07001276 However, since users cannot do anything actionable to
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001277 address this, by default the kernel will issue only a single
1278 warning for the first use of unseeded randomness.
1279
1280 Say Y here if you want to receive warnings for all uses of
1281 unseeded randomness. This will be of use primarily for
Thibaut Sautereau4c5d1142018-09-04 15:46:23 -07001282 those developers interested in improving the security of
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001283 Linux kernels running on their architecture (or
1284 subarchitecture).
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001285
Linus Torvalds1da177e2005-04-16 15:20:36 -07001286config DEBUG_KOBJECT
1287 bool "kobject debugging"
1288 depends on DEBUG_KERNEL
1289 help
1290 If you say Y here, some extra kobject debugging messages will be sent
Mike Rapoportaca52c32018-10-30 15:07:44 -07001291 to the syslog.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292
Russell Kingc817a672013-06-27 15:06:14 +01001293config DEBUG_KOBJECT_RELEASE
1294 bool "kobject release debugging"
Linus Torvalds2a999aa2013-10-29 08:33:36 -07001295 depends on DEBUG_OBJECTS_TIMERS
Russell Kingc817a672013-06-27 15:06:14 +01001296 help
1297 kobjects are reference counted objects. This means that their
1298 last reference count put is not predictable, and the kobject can
1299 live on past the point at which a driver decides to drop it's
1300 initial reference to the kobject gained on allocation. An
1301 example of this would be a struct device which has just been
1302 unregistered.
1303
1304 However, some buggy drivers assume that after such an operation,
1305 the memory backing the kobject can be immediately freed. This
1306 goes completely against the principles of a refcounted object.
1307
1308 If you say Y here, the kernel will delay the release of kobjects
1309 on the last reference count to improve the visibility of this
1310 kind of kobject release bug.
1311
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001312config HAVE_DEBUG_BUGVERBOSE
1313 bool
1314
Changbin Du3be5cbc2019-12-06 17:03:48 -08001315menu "Debug kernel data structures"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001316
Dave Jones199a9af2006-09-29 01:59:00 -07001317config DEBUG_LIST
1318 bool "Debug linked list manipulation"
Arnd Bergmann4520bcb2016-08-26 17:42:00 +02001319 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
Dave Jones199a9af2006-09-29 01:59:00 -07001320 help
1321 Enable this to turn on extended checks in the linked-list
1322 walking routines.
1323
1324 If unsure, say N.
1325
Davidlohr Bueso8e18fae2019-05-14 15:42:46 -07001326config DEBUG_PLIST
Dan Streetmanb8cfff62014-06-04 16:11:54 -07001327 bool "Debug priority linked list manipulation"
1328 depends on DEBUG_KERNEL
1329 help
1330 Enable this to turn on extended checks in the priority-ordered
1331 linked-list (plist) walking routines. This checks the entire
1332 list multiple times during each manipulation.
1333
1334 If unsure, say N.
1335
Jens Axboed6ec0842007-10-22 20:01:06 +02001336config DEBUG_SG
1337 bool "Debug SG table operations"
1338 depends on DEBUG_KERNEL
1339 help
1340 Enable this to turn on checks on scatter-gather tables. This can
1341 help find problems with drivers that do not properly initialize
1342 their sg tables.
1343
1344 If unsure, say N.
1345
Arjan van de Ven1b2439d2008-08-15 15:29:38 -07001346config DEBUG_NOTIFIERS
1347 bool "Debug notifier call chains"
1348 depends on DEBUG_KERNEL
1349 help
1350 Enable this to turn on sanity checking for notifier call chains.
1351 This is most useful for kernel developers to make sure that
1352 modules properly unregister themselves from notifier chains.
1353 This is a relatively cheap check but if you care about maximum
1354 performance, say N.
1355
Changbin Du3be5cbc2019-12-06 17:03:48 -08001356config BUG_ON_DATA_CORRUPTION
1357 bool "Trigger a BUG when data corruption is detected"
1358 select DEBUG_LIST
1359 help
1360 Select this option if the kernel should BUG when it encounters
1361 data corruption in kernel memory structures when they get checked
1362 for validity.
1363
1364 If unsure, say N.
1365
1366endmenu
1367
David Howellse0e81732009-09-02 09:13:40 +01001368config DEBUG_CREDENTIALS
1369 bool "Debug credential management"
1370 depends on DEBUG_KERNEL
1371 help
1372 Enable this to turn on some debug checking for credential
1373 management. The additional code keeps track of the number of
1374 pointers from task_structs to any given cred struct, and checks to
1375 see that this number never exceeds the usage count of the cred
1376 struct.
1377
1378 Furthermore, if SELinux is enabled, this also checks that the
1379 security pointer in the cred struct is never seen to be invalid.
1380
1381 If unsure, say N.
1382
Paul E. McKenney43a0a2a2017-05-17 09:19:44 -07001383source "kernel/rcu/Kconfig.debug"
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001384
Tejun Heof303fccb2016-02-09 17:59:38 -05001385config DEBUG_WQ_FORCE_RR_CPU
1386 bool "Force round-robin CPU selection for unbound work items"
1387 depends on DEBUG_KERNEL
1388 default n
1389 help
1390 Workqueue used to implicitly guarantee that work items queued
1391 without explicit CPU specified are put on the local CPU. This
1392 guarantee is no longer true and while local CPU is still
1393 preferred work items may be put on foreign CPUs. Kernel
1394 parameter "workqueue.debug_force_rr_cpu" is added to force
1395 round-robin CPU selection to flush out usages which depend on the
1396 now broken guarantee. This config option enables the debug
1397 feature by default. When enabled, memory and cache locality will
1398 be impacted.
1399
Tejun Heo870d6652008-08-25 19:47:25 +09001400config DEBUG_BLOCK_EXT_DEVT
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -08001401 bool "Force extended block device numbers and spread them"
Tejun Heo870d6652008-08-25 19:47:25 +09001402 depends on DEBUG_KERNEL
1403 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +02001404 default n
Tejun Heo870d6652008-08-25 19:47:25 +09001405 help
Tejun Heo0e11e342008-10-13 10:46:01 +02001406 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1407 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1408 YOU ARE DOING. Distros, please enable this and fix whatever
1409 is broken.
1410
Tejun Heo870d6652008-08-25 19:47:25 +09001411 Conventionally, block device numbers are allocated from
1412 predetermined contiguous area. However, extended block area
1413 may introduce non-contiguous block device numbers. This
1414 option forces most block device numbers to be allocated from
1415 the extended space and spreads them to discover kernel or
1416 userland code paths which assume predetermined contiguous
1417 device number allocation.
1418
Tejun Heo55dc7db2008-09-01 13:44:35 +02001419 Note that turning on this debug option shuffles all the
1420 device numbers for all IDE and SCSI devices including libata
1421 ones, so root partition specified using device number
1422 directly (via rdev or root=MAJ:MIN) won't work anymore.
1423 Textual device names (root=/dev/sdXn) will continue to work.
1424
Tejun Heo870d6652008-08-25 19:47:25 +09001425 Say N if you are unsure.
1426
Thomas Gleixner757c9892016-02-26 18:43:32 +00001427config CPU_HOTPLUG_STATE_CONTROL
1428 bool "Enable CPU hotplug state control"
1429 depends on DEBUG_KERNEL
1430 depends on HOTPLUG_CPU
1431 default n
1432 help
1433 Allows to write steps between "offline" and "online" to the CPUs
1434 sysfs target file so states can be stepped granular. This is a debug
1435 option for now as the hotplug machinery cannot be stopped and
1436 restarted at arbitrary points yet.
1437
1438 Say N if your are unsure.
1439
Changbin Du09a74952019-12-06 17:03:51 -08001440config LATENCYTOP
1441 bool "Latency measuring infrastructure"
1442 depends on DEBUG_KERNEL
1443 depends on STACKTRACE_SUPPORT
1444 depends on PROC_FS
1445 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1446 select KALLSYMS
1447 select KALLSYMS_ALL
1448 select STACKTRACE
1449 select SCHEDSTATS
1450 select SCHED_DEBUG
1451 help
1452 Enable this option if you want to use the LatencyTOP tool
1453 to find out which userspace is blocking on what kernel operations.
1454
1455source "kernel/trace/Kconfig"
1456
1457config PROVIDE_OHCI1394_DMA_INIT
1458 bool "Remote debugging over FireWire early on boot"
1459 depends on PCI && X86
1460 help
1461 If you want to debug problems which hang or crash the kernel early
1462 on boot and the crashing machine has a FireWire port, you can use
1463 this feature to remotely access the memory of the crashed machine
1464 over FireWire. This employs remote DMA as part of the OHCI1394
1465 specification which is now the standard for FireWire controllers.
1466
1467 With remote DMA, you can monitor the printk buffer remotely using
1468 firescope and access all memory below 4GB using fireproxy from gdb.
1469 Even controlling a kernel debugger is possible using remote DMA.
1470
1471 Usage:
1472
1473 If ohci1394_dma=early is used as boot parameter, it will initialize
1474 all OHCI1394 controllers which are found in the PCI config space.
1475
1476 As all changes to the FireWire bus such as enabling and disabling
1477 devices cause a bus reset and thereby disable remote DMA for all
1478 devices, be sure to have the cable plugged and FireWire enabled on
1479 the debugging host before booting the debug target for debugging.
1480
1481 This code (~1k) is freed after boot. By then, the firewire stack
1482 in charge of the OHCI-1394 controllers should be used instead.
1483
1484 See Documentation/debugging-via-ohci1394.txt for more information.
1485
Changbin Du045f6d72019-12-17 20:51:56 -08001486source "samples/Kconfig"
1487
1488config ARCH_HAS_DEVMEM_IS_ALLOWED
1489 bool
1490
1491config STRICT_DEVMEM
1492 bool "Filter access to /dev/mem"
1493 depends on MMU && DEVMEM
1494 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
1495 default y if PPC || X86 || ARM64
1496 help
1497 If this option is disabled, you allow userspace (root) access to all
1498 of memory, including kernel and userspace memory. Accidental
1499 access to this is obviously disastrous, but specific access can
1500 be used by people debugging the kernel. Note that with PAT support
1501 enabled, even in this case there are restrictions on /dev/mem
1502 use due to the cache aliasing requirements.
1503
1504 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1505 file only allows userspace access to PCI space and the BIOS code and
1506 data regions. This is sufficient for dosemu and X and all common
1507 users of /dev/mem.
1508
1509 If in doubt, say Y.
1510
1511config IO_STRICT_DEVMEM
1512 bool "Filter I/O access to /dev/mem"
1513 depends on STRICT_DEVMEM
1514 help
1515 If this option is disabled, you allow userspace (root) access to all
1516 io-memory regardless of whether a driver is actively using that
1517 range. Accidental access to this is obviously disastrous, but
1518 specific access can be used by people debugging kernel drivers.
1519
1520 If this option is switched on, the /dev/mem file only allows
1521 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1522 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1523 if the driver using a given range cannot be disabled.
1524
1525 If in doubt, say Y.
1526
1527menu "$(SRCARCH) Debugging"
1528
1529source "arch/$(SRCARCH)/Kconfig.debug"
1530
1531endmenu
1532
1533menu "Kernel Testing and Coverage"
1534
Changbin Du09a74952019-12-06 17:03:51 -08001535source "lib/kunit/Kconfig"
1536
Akinobu Mita8d438282012-07-30 14:43:02 -07001537config NOTIFIER_ERROR_INJECTION
1538 tristate "Notifier error injection"
1539 depends on DEBUG_KERNEL
1540 select DEBUG_FS
1541 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001542 This option provides the ability to inject artificial errors to
Akinobu Mita8d438282012-07-30 14:43:02 -07001543 specified notifier chain callbacks. It is useful to test the error
1544 handling of notifier call chain failures.
1545
1546 Say N if unsure.
1547
Akinobu Mita048b9c32012-07-30 14:43:07 -07001548config PM_NOTIFIER_ERROR_INJECT
1549 tristate "PM notifier error injection module"
1550 depends on PM && NOTIFIER_ERROR_INJECTION
1551 default m if PM_DEBUG
1552 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001553 This option provides the ability to inject artificial errors to
Akinobu Mita048b9c32012-07-30 14:43:07 -07001554 PM notifier chain callbacks. It is controlled through debugfs
1555 interface /sys/kernel/debug/notifier-error-inject/pm
1556
1557 If the notifier call chain should be failed with some events
1558 notified, write the error code to "actions/<notifier event>/error".
1559
1560 Example: Inject PM suspend error (-12 = -ENOMEM)
1561
1562 # cd /sys/kernel/debug/notifier-error-inject/pm/
1563 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1564 # echo mem > /sys/power/state
1565 bash: echo: write error: Cannot allocate memory
1566
1567 To compile this code as a module, choose M here: the module will
1568 be called pm-notifier-error-inject.
1569
1570 If unsure, say N.
1571
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001572config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1573 tristate "OF reconfig notifier error injection module"
1574 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001575 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001576 This option provides the ability to inject artificial errors to
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001577 OF reconfig notifier chain callbacks. It is controlled
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001578 through debugfs interface under
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001579 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001580
1581 If the notifier call chain should be failed with some events
1582 notified, write the error code to "actions/<notifier event>/error".
1583
1584 To compile this code as a module, choose M here: the module will
Akinobu Mitae12a95f2013-04-30 15:28:49 -07001585 be called of-reconfig-notifier-error-inject.
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001586
1587 If unsure, say N.
1588
Nikolay Aleksandrov02fff962015-11-28 13:45:28 +01001589config NETDEV_NOTIFIER_ERROR_INJECT
1590 tristate "Netdev notifier error injection module"
1591 depends on NET && NOTIFIER_ERROR_INJECTION
1592 help
1593 This option provides the ability to inject artificial errors to
1594 netdevice notifier chain callbacks. It is controlled through debugfs
1595 interface /sys/kernel/debug/notifier-error-inject/netdev
1596
1597 If the notifier call chain should be failed with some events
1598 notified, write the error code to "actions/<notifier event>/error".
1599
1600 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1601
1602 # cd /sys/kernel/debug/notifier-error-inject/netdev
1603 # echo -22 > actions/NETDEV_CHANGEMTU/error
1604 # ip link set eth0 mtu 1024
1605 RTNETLINK answers: Invalid argument
1606
1607 To compile this code as a module, choose M here: the module will
1608 be called netdev-notifier-error-inject.
1609
1610 If unsure, say N.
1611
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001612config FUNCTION_ERROR_INJECTION
1613 def_bool y
1614 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1615
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001616config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001617 bool "Fault-injection framework"
1618 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001619 help
1620 Provide fault-injection framework.
1621 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001622
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001623config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001624 bool "Fault-injection capability for kmalloc"
1625 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001626 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001627 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001628 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001629
Akinobu Mita933e3122006-12-08 02:39:45 -08001630config FAIL_PAGE_ALLOC
1631 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001632 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001633 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001634 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001635
Akinobu Mitac17bb492006-12-08 02:39:46 -08001636config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001637 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001638 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001639 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001640 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001641
Jens Axboe581d4e22008-09-14 05:56:33 -07001642config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d01432010-07-21 16:05:53 +09001643 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001644 depends on FAULT_INJECTION && BLOCK
1645 help
1646 Provide fault-injection capability on end IO handling. This
1647 will make the block layer "forget" an interrupt as configured,
1648 thus exercising the error handling.
1649
1650 Only works with drivers that use the generic timeout handling,
1651 for others it wont do anything.
1652
Davidlohr Buesoab51fba2015-06-29 23:26:02 -07001653config FAIL_FUTEX
1654 bool "Fault-injection capability for futexes"
1655 select DEBUG_FS
1656 depends on FAULT_INJECTION && FUTEX
1657 help
1658 Provide fault-injection capability for futexes.
1659
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001660config FAULT_INJECTION_DEBUG_FS
1661 bool "Debugfs entries for fault-injection capabilities"
1662 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1663 help
1664 Enable configuration of fault-injection capabilities via debugfs.
1665
Masami Hiramatsu4b1a29a2018-01-13 02:56:03 +09001666config FAIL_FUNCTION
1667 bool "Fault-injection capability for functions"
1668 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1669 help
1670 Provide function-based fault-injection capability.
1671 This will allow you to override a specific function with a return
1672 with given return value. As a result, function caller will see
1673 an error value and have to handle it. This is useful to test the
1674 error handling in various subsystems.
1675
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001676config FAIL_MMC_REQUEST
1677 bool "Fault-injection capability for MMC IO"
1678 depends on FAULT_INJECTION_DEBUG_FS && MMC
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001679 help
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001680 Provide fault-injection capability for MMC IO.
1681 This will make the mmc core return data errors. This is
1682 useful to test the error handling in the mmc block device
1683 and to test how the mmc host driver handles retries from
1684 the block device.
Akinobu Mita1df49002007-02-20 13:57:56 -08001685
1686config FAULT_INJECTION_STACKTRACE_FILTER
1687 bool "stacktrace filter for fault-injection capabilities"
1688 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001689 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001690 select STACKTRACE
Stefan Agnerf9b58e82018-09-30 23:02:33 +01001691 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
Akinobu Mita1df49002007-02-20 13:57:56 -08001692 help
1693 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001694
Changbin Du09a74952019-12-06 17:03:51 -08001695config ARCH_HAS_KCOV
1696 bool
Arjan van de Ven97455122008-01-25 21:08:34 +01001697 help
Changbin Du09a74952019-12-06 17:03:51 -08001698 An architecture should select this when it can successfully
1699 build and run with CONFIG_KCOV. This typically requires
1700 disabling instrumentation for some early boot code.
Arjan van de Ven97455122008-01-25 21:08:34 +01001701
Changbin Du09a74952019-12-06 17:03:51 -08001702config CC_HAS_SANCOV_TRACE_PC
1703 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001704
Changbin Du09a74952019-12-06 17:03:51 -08001705
1706config KCOV
1707 bool "Code coverage for fuzzing"
1708 depends on ARCH_HAS_KCOV
1709 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1710 select DEBUG_FS
1711 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001712 help
Changbin Du09a74952019-12-06 17:03:51 -08001713 KCOV exposes kernel code coverage information in a form suitable
1714 for coverage-guided fuzzing (randomized testing).
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001715
Changbin Du09a74952019-12-06 17:03:51 -08001716 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1717 different machines and across reboots. If you need stable PC values,
1718 disable RANDOMIZE_BASE.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001719
Changbin Du09a74952019-12-06 17:03:51 -08001720 For more details, see Documentation/dev-tools/kcov.rst.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001721
Changbin Du09a74952019-12-06 17:03:51 -08001722config KCOV_ENABLE_COMPARISONS
1723 bool "Enable comparison operands collection by KCOV"
1724 depends on KCOV
1725 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1726 help
1727 KCOV also exposes operands of every comparison in the instrumented
1728 code along with operand sizes and PCs of the comparison instructions.
1729 These operands can be used by fuzzing engines to improve the quality
1730 of fuzzing coverage.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001731
Changbin Du09a74952019-12-06 17:03:51 -08001732config KCOV_INSTRUMENT_ALL
1733 bool "Instrument all code by default"
1734 depends on KCOV
1735 default y
1736 help
1737 If you are doing generic system call fuzzing (like e.g. syzkaller),
1738 then you will want to instrument the whole kernel and you should
1739 say y here. If you are doing more targeted fuzzing (like e.g.
1740 filesystem fuzzing with AFL) then you will want to enable coverage
1741 for more specific subsets of files, and should say n here.
Brendan Higgins84bc8092019-09-23 02:02:36 -07001742
Vincent Legolld3deafa2018-02-06 15:38:38 -08001743menuconfig RUNTIME_TESTING_MENU
1744 bool "Runtime Testing"
Anders Roxell908009e82018-02-21 14:46:05 -08001745 def_bool y
Vincent Legolld3deafa2018-02-06 15:38:38 -08001746
1747if RUNTIME_TESTING_MENU
Dave Hansen881c5142013-07-01 13:04:44 -07001748
1749config LKDTM
1750 tristate "Linux Kernel Dump Test Tool Module"
1751 depends on DEBUG_FS
Dave Hansen881c5142013-07-01 13:04:44 -07001752 help
1753 This module enables testing of the different dumping mechanisms by
1754 inducing system failures at predefined crash points.
1755 If you don't need it: say N
1756 Choose M here to compile this code as a module. The module will be
1757 called lkdtm.
1758
1759 Documentation on how to use the module can be found in
Mauro Carvalho Chehab10ffebb2019-06-12 14:52:44 -03001760 Documentation/fault-injection/provoke-crashes.rst
Dave Hansen881c5142013-07-01 13:04:44 -07001761
1762config TEST_LIST_SORT
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001763 tristate "Linked list sorting test"
1764 depends on DEBUG_KERNEL || m
Dave Hansen881c5142013-07-01 13:04:44 -07001765 help
1766 Enable this to turn on 'list_sort()' function test. This test is
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001767 executed only once during system boot (so affects only boot time),
1768 or at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001769
1770 If unsure, say N.
1771
Ian Rogers6e246282020-02-13 23:51:29 -08001772config TEST_MIN_HEAP
1773 tristate "Min heap test"
1774 depends on DEBUG_KERNEL || m
1775 help
1776 Enable this to turn on min heap function tests. This test is
1777 executed only once during system boot (so affects only boot time),
1778 or at module load time.
1779
1780 If unsure, say N.
1781
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001782config TEST_SORT
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001783 tristate "Array-based sort test"
1784 depends on DEBUG_KERNEL || m
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001785 help
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001786 This option enables the self-test function of 'sort()' at boot,
1787 or at module load time.
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001788
1789 If unsure, say N.
1790
Dave Hansen881c5142013-07-01 13:04:44 -07001791config KPROBES_SANITY_TEST
1792 bool "Kprobes sanity tests"
1793 depends on DEBUG_KERNEL
1794 depends on KPROBES
Dave Hansen881c5142013-07-01 13:04:44 -07001795 help
1796 This option provides for testing basic kprobes functionality on
Masami Hiramatsu5a6cf772018-06-20 01:05:07 +09001797 boot. Samples of kprobe and kretprobe are inserted and
Dave Hansen881c5142013-07-01 13:04:44 -07001798 verified for functionality.
1799
1800 Say N if you are unsure.
1801
1802config BACKTRACE_SELF_TEST
1803 tristate "Self test for the backtrace code"
1804 depends on DEBUG_KERNEL
Dave Hansen881c5142013-07-01 13:04:44 -07001805 help
1806 This option provides a kernel module that can be used to test
1807 the kernel stack backtrace code. This option is not useful
1808 for distributions or general kernels, but only for kernel
1809 developers working on architecture code.
1810
1811 Note that if you want to also test saved backtraces, you will
1812 have to enable STACKTRACE as well.
1813
1814 Say N if you are unsure.
1815
Michel Lespinasse910a7422012-10-08 16:30:39 -07001816config RBTREE_TEST
1817 tristate "Red-Black tree test"
Cody P Schafer7c993e12013-09-11 14:25:19 -07001818 depends on DEBUG_KERNEL
Michel Lespinasse910a7422012-10-08 16:30:39 -07001819 help
1820 A benchmark measuring the performance of the rbtree library.
1821 Also includes rbtree invariant checks.
1822
Ferdinand Blomqvist4b4f3ac2019-06-20 17:10:33 +03001823config REED_SOLOMON_TEST
1824 tristate "Reed-Solomon library test"
1825 depends on DEBUG_KERNEL || m
1826 select REED_SOLOMON
1827 select REED_SOLOMON_ENC16
1828 select REED_SOLOMON_DEC16
1829 help
1830 This option enables the self-test function of rslib at boot,
1831 or at module load time.
1832
1833 If unsure, say N.
1834
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001835config INTERVAL_TREE_TEST
1836 tristate "Interval tree test"
Davidlohr Bueso0f789b62017-07-10 15:51:43 -07001837 depends on DEBUG_KERNEL
Chris Wilsona88cc102014-03-17 12:21:54 +00001838 select INTERVAL_TREE
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001839 help
1840 A benchmark measuring the performance of the interval tree library
1841
Greg Thelen623fd802013-11-12 15:08:34 -08001842config PERCPU_TEST
1843 tristate "Per cpu operations test"
1844 depends on m && DEBUG_KERNEL
1845 help
1846 Enable this option to build test module which validates per-cpu
1847 operations.
1848
1849 If unsure, say N.
1850
Dave Hansen881c5142013-07-01 13:04:44 -07001851config ATOMIC64_SELFTEST
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001852 tristate "Perform an atomic64_t self-test"
Dave Hansen881c5142013-07-01 13:04:44 -07001853 help
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001854 Enable this option to test the atomic64_t functions at boot or
1855 at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001856
1857 If unsure, say N.
1858
1859config ASYNC_RAID6_TEST
1860 tristate "Self test for hardware accelerated raid6 recovery"
1861 depends on ASYNC_RAID6_RECOV
1862 select ASYNC_MEMCPY
1863 ---help---
1864 This is a one-shot self test that permutes through the
1865 recovery of all the possible two disk failure scenarios for a
1866 N-disk array. Recovery is performed with the asynchronous
1867 raid6 recovery routines, and will optionally use an offload
1868 engine if one is available.
1869
1870 If unsure, say N.
1871
Andy Shevchenko64d1d772015-02-12 15:02:21 -08001872config TEST_HEXDUMP
1873 tristate "Test functions located in the hexdump module at runtime"
1874
Dave Hansen881c5142013-07-01 13:04:44 -07001875config TEST_STRING_HELPERS
1876 tristate "Test functions located in the string_helpers module at runtime"
1877
Tobin C. Harding0b0600c82019-04-05 12:58:59 +11001878config TEST_STRSCPY
1879 tristate "Test strscpy*() family of functions at runtime"
1880
Dave Hansen881c5142013-07-01 13:04:44 -07001881config TEST_KSTRTOX
1882 tristate "Test kstrto*() family of functions at runtime"
1883
Rasmus Villemoes707cc722015-11-06 16:30:29 -08001884config TEST_PRINTF
1885 tristate "Test printf() family of functions at runtime"
1886
David Decotigny5fd003f2016-02-19 09:24:00 -05001887config TEST_BITMAP
1888 tristate "Test bitmap_*() family of functions at runtime"
David Decotigny5fd003f2016-02-19 09:24:00 -05001889 help
1890 Enable this option to test the bitmap functions at boot.
1891
1892 If unsure, say N.
1893
Johannes Berg0e2dc702018-06-20 08:58:30 +02001894config TEST_BITFIELD
1895 tristate "Test bitfield functions at runtime"
1896 help
1897 Enable this option to test the bitfield functions at boot.
1898
1899 If unsure, say N.
1900
Andy Shevchenkocfaff0e2016-05-30 17:40:41 +03001901config TEST_UUID
1902 tristate "Test functions located in the uuid module at runtime"
1903
Matthew Wilcoxad3d6c72017-11-07 14:57:46 -05001904config TEST_XARRAY
1905 tristate "Test the XArray code at runtime"
1906
Rasmus Villemoes455a35a2018-05-08 00:36:28 +02001907config TEST_OVERFLOW
1908 tristate "Test check_*_overflow() functions at runtime"
1909
Thomas Graf7e1e7762014-08-02 11:47:44 +02001910config TEST_RHASHTABLE
Geert Uytterhoeven9d6dbe12015-01-29 15:40:25 +01001911 tristate "Perform selftest on resizable hash table"
Thomas Graf7e1e7762014-08-02 11:47:44 +02001912 help
1913 Enable this option to test the rhashtable functions at boot.
1914
1915 If unsure, say N.
1916
George Spelvin468a9422016-05-26 22:11:51 -04001917config TEST_HASH
1918 tristate "Perform selftest on hash functions"
George Spelvin468a9422016-05-26 22:11:51 -04001919 help
Jason A. Donenfeld2c956a62017-01-08 13:54:00 +01001920 Enable this option to test the kernel's integer (<linux/hash.h>),
1921 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
1922 hash functions on boot (or module load).
George Spelvin468a9422016-05-26 22:11:51 -04001923
1924 This is intended to help people writing architecture-specific
1925 optimized versions. If unsure, say N.
1926
Matthew Wilcox8ab8ba32018-06-18 16:59:29 -04001927config TEST_IDA
1928 tristate "Perform selftest on IDA functions"
1929
Jiri Pirko44091d22017-02-03 10:29:06 +01001930config TEST_PARMAN
1931 tristate "Perform selftest on priority array manager"
Jiri Pirko44091d22017-02-03 10:29:06 +01001932 depends on PARMAN
1933 help
1934 Enable this option to test priority array manager on boot
1935 (or module load).
1936
1937 If unsure, say N.
1938
Daniel Lezcano6aed82d2019-05-27 22:55:19 +02001939config TEST_IRQ_TIMINGS
1940 bool "IRQ timings selftest"
1941 depends on IRQ_TIMINGS
1942 help
1943 Enable this option to test the irq timings code on boot.
1944
1945 If unsure, say N.
1946
Valentin Rothberg8a6f0b42014-10-13 15:51:38 -07001947config TEST_LKM
Kees Cook93e9ef82014-01-23 15:54:37 -08001948 tristate "Test module loading with 'hello world' module"
Kees Cook93e9ef82014-01-23 15:54:37 -08001949 depends on m
1950 help
1951 This builds the "test_module" module that emits "Hello, world"
1952 on printk when loaded. It is designed to be used for basic
1953 evaluation of the module loading subsystem (for example when
1954 validating module verification). It lacks any extra dependencies,
1955 and will not normally be loaded by the system unless explicitly
1956 requested by name.
1957
1958 If unsure, say N.
1959
Uladzislau Rezki (Sony)3f21a6b2019-03-05 15:43:34 -08001960config TEST_VMALLOC
1961 tristate "Test module for stress/performance analysis of vmalloc allocator"
1962 default n
1963 depends on MMU
1964 depends on m
1965 help
1966 This builds the "test_vmalloc" module that should be used for
1967 stress and performance analysis. So, any new change for vmalloc
1968 subsystem can be evaluated from performance and stability point
1969 of view.
1970
1971 If unsure, say N.
1972
Kees Cook3e2a4c12014-01-23 15:54:38 -08001973config TEST_USER_COPY
1974 tristate "Test user/kernel boundary protections"
Kees Cook3e2a4c12014-01-23 15:54:38 -08001975 depends on m
1976 help
1977 This builds the "test_user_copy" module that runs sanity checks
1978 on the copy_to/from_user infrastructure, making sure basic
1979 user/kernel boundary testing is working. If it fails to load,
1980 a regression has been detected in the user/kernel memory boundary
1981 protections.
1982
1983 If unsure, say N.
1984
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001985config TEST_BPF
1986 tristate "Test BPF filter functionality"
Randy Dunlap98920ba2014-05-13 09:58:44 -07001987 depends on m && NET
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001988 help
1989 This builds the "test_bpf" module that runs various test vectors
1990 against the BPF interpreter or BPF JIT compiler depending on the
1991 current setting. This is in particular useful for BPF JIT compiler
1992 development, but also to run regression tests against changes in
Alexei Starovoitov3c731eb2014-09-26 00:17:07 -07001993 the interpreter code. It also enables test stubs for eBPF maps and
1994 verifier used by user space verifier testsuite.
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001995
1996 If unsure, say N.
1997
Mahesh Bandewar509e56b2019-07-01 14:39:01 -07001998config TEST_BLACKHOLE_DEV
1999 tristate "Test blackhole netdev functionality"
2000 depends on m && NET
2001 help
2002 This builds the "test_blackhole_dev" module that validates the
2003 data path through this blackhole netdev.
2004
2005 If unsure, say N.
2006
Yury Norovdceeb3e2018-02-06 15:38:27 -08002007config FIND_BIT_BENCHMARK
Yury Norov4441fca2017-11-17 15:28:31 -08002008 tristate "Test find_bit functions"
Yury Norov4441fca2017-11-17 15:28:31 -08002009 help
2010 This builds the "test_find_bit" module that measure find_*_bit()
2011 functions performance.
2012
2013 If unsure, say N.
2014
Kees Cook0a8adf52014-07-14 14:38:12 -07002015config TEST_FIRMWARE
2016 tristate "Test firmware loading via userspace interface"
Kees Cook0a8adf52014-07-14 14:38:12 -07002017 depends on FW_LOADER
2018 help
2019 This builds the "test_firmware" module that creates a userspace
2020 interface for testing firmware loading. This can be used to
2021 control the triggering of firmware loading without needing an
2022 actual firmware-using device. The contents can be rechecked by
2023 userspace.
2024
2025 If unsure, say N.
2026
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07002027config TEST_SYSCTL
2028 tristate "sysctl test driver"
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07002029 depends on PROC_SYSCTL
2030 help
2031 This builds the "test_sysctl" module. This driver enables to test the
2032 proc sysctl interfaces available to drivers safely without affecting
2033 production knobs which might alter system functionality.
2034
2035 If unsure, say N.
2036
Iurii Zaikin2cb80db2019-09-23 02:02:47 -07002037config SYSCTL_KUNIT_TEST
Alan Maguirec475c772020-01-06 22:28:20 +00002038 tristate "KUnit test for sysctl"
Iurii Zaikin2cb80db2019-09-23 02:02:47 -07002039 depends on KUNIT
2040 help
2041 This builds the proc sysctl unit test, which runs on boot.
2042 Tests the API contract and implementation correctness of sysctl.
2043 For more information on KUnit and unit tests in general please refer
2044 to the KUnit documentation in Documentation/dev-tools/kunit/.
2045
2046 If unsure, say N.
2047
David Gowea2dd7c2019-10-24 15:46:31 -07002048config LIST_KUNIT_TEST
Alan Maguirec475c772020-01-06 22:28:20 +00002049 tristate "KUnit Test for Kernel Linked-list structures"
David Gowea2dd7c2019-10-24 15:46:31 -07002050 depends on KUNIT
2051 help
2052 This builds the linked list KUnit test suite.
2053 It tests that the API and basic functionality of the list_head type
2054 and associated macros.
2055
2056 KUnit tests run during boot and output the results to the debug log
2057 in TAP format (http://testanything.org/). Only useful for kernel devs
2058 running the KUnit test harness, and not intended for inclusion into a
2059 production build.
2060
2061 For more information on KUnit and unit tests in general please refer
2062 to the KUnit documentation in Documentation/dev-tools/kunit/.
2063
2064 If unsure, say N.
2065
David Rileye704f932014-06-16 14:58:32 -07002066config TEST_UDELAY
2067 tristate "udelay test driver"
David Rileye704f932014-06-16 14:58:32 -07002068 help
2069 This builds the "udelay_test" module that helps to make sure
2070 that udelay() is working properly.
2071
2072 If unsure, say N.
2073
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02002074config TEST_STATIC_KEYS
2075 tristate "Test static keys"
Jason Baron579e1ac2015-07-30 03:59:44 +00002076 depends on m
2077 help
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02002078 Test the static key interfaces.
Jason Baron579e1ac2015-07-30 03:59:44 +00002079
2080 If unsure, say N.
2081
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002082config TEST_KMOD
2083 tristate "kmod stress tester"
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002084 depends on m
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002085 depends on NETDEVICES && NET_CORE && INET # for TUN
YueHaibingae3d6a32019-04-25 22:23:44 -07002086 depends on BLOCK
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002087 select TEST_LKM
2088 select XFS_FS
2089 select TUN
2090 select BTRFS_FS
2091 help
2092 Test the kernel's module loading mechanism: kmod. kmod implements
2093 support to load modules using the Linux kernel's usermode helper.
2094 This test provides a series of tests against kmod.
2095
2096 Although technically you can either build test_kmod as a module or
2097 into the kernel we disallow building it into the kernel since
2098 it stress tests request_module() and this will very likely cause
2099 some issues by taking over precious threads available from other
2100 module load requests, ultimately this could be fatal.
2101
2102 To run tests run:
2103
2104 tools/testing/selftests/kmod/kmod.sh --help
2105
2106 If unsure, say N.
2107
Florian Fainellie4dace32017-09-08 16:15:31 -07002108config TEST_DEBUG_VIRTUAL
2109 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2110 depends on DEBUG_VIRTUAL
2111 help
2112 Test the kernel's ability to detect incorrect calls to
2113 virt_to_phys() done against the non-linear part of the
2114 kernel's virtual address map.
2115
2116 If unsure, say N.
2117
Alexander Shishkince76d932018-10-05 15:43:05 +03002118config TEST_MEMCAT_P
2119 tristate "Test memcat_p() helper function"
2120 help
2121 Test the memcat_p() helper for correctly merging two
2122 pointer arrays together.
2123
2124 If unsure, say N.
2125
Joe Lawrencea2818ee2019-01-09 13:43:29 +01002126config TEST_LIVEPATCH
2127 tristate "Test livepatching"
2128 default n
Joe Lawrencebae05432019-01-31 11:41:24 -05002129 depends on DYNAMIC_DEBUG
Joe Lawrencea2818ee2019-01-09 13:43:29 +01002130 depends on LIVEPATCH
2131 depends on m
2132 help
2133 Test kernel livepatching features for correctness. The tests will
2134 load test modules that will be livepatched in various scenarios.
2135
2136 To run all the livepatching tests:
2137
2138 make -C tools/testing/selftests TARGETS=livepatch run_tests
2139
2140 Alternatively, individual tests may be invoked:
2141
2142 tools/testing/selftests/livepatch/test-callbacks.sh
2143 tools/testing/selftests/livepatch/test-livepatch.sh
2144 tools/testing/selftests/livepatch/test-shadow-vars.sh
2145
2146 If unsure, say N.
2147
Jiri Pirko0a020d42018-11-14 08:22:28 +00002148config TEST_OBJAGG
2149 tristate "Perform selftest on object aggreration manager"
2150 default n
2151 depends on OBJAGG
2152 help
2153 Enable this option to test object aggregation manager on boot
2154 (or module load).
2155
Jiri Pirko0a020d42018-11-14 08:22:28 +00002156
Kees Cook50ceaa95e2019-01-23 12:24:32 -07002157config TEST_STACKINIT
2158 tristate "Test level of stack variable initialization"
2159 help
2160 Test if the kernel is zero-initializing stack variables and
2161 padding. Coverage is controlled by compiler flags,
2162 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2163 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2164
2165 If unsure, say N.
2166
Alexander Potapenko5015a302019-07-16 16:27:27 -07002167config TEST_MEMINIT
2168 tristate "Test heap/page initialization"
2169 help
2170 Test if the kernel is zero-initializing heap and page allocations.
2171 This can be useful to test init_on_alloc and init_on_free features.
2172
2173 If unsure, say N.
2174
Vincent Legolld3deafa2018-02-06 15:38:38 -08002175endif # RUNTIME_TESTING_MENU
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002176
2177config MEMTEST
2178 bool "Memtest"
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002179 ---help---
2180 This option adds a kernel parameter 'memtest', which allows memtest
2181 to be set.
2182 memtest=0, mean disabled; -- default
2183 memtest=1, mean do 1 test pattern;
2184 ...
2185 memtest=17, mean do 17 test patterns.
2186 If you are unsure how to answer this question, answer N.
2187
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002188
Christoph Hellwig06ec64b2018-07-31 13:39:31 +02002189
Branden Bonabyaf9ca6f2019-10-03 17:01:49 -04002190config HYPERV_TESTING
2191 bool "Microsoft Hyper-V driver testing"
2192 default n
2193 depends on HYPERV && DEBUG_FS
2194 help
2195 Select this option to enable Hyper-V vmbus testing.
2196
Changbin Du045f6d72019-12-17 20:51:56 -08002197endmenu # "Kernel Testing and Coverage"
2198
Christoph Hellwig06ec64b2018-07-31 13:39:31 +02002199endmenu # Kernel hacking