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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
Greg Kroah-Hartman239a5792020-02-10 13:11:42 -0800101 depends on (DEBUG_FS || PROC_FS)
Dave Hansen604ff0d2013-07-01 13:04:49 -0700102 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,
Greg Kroah-Hartman239a5792020-02-10 13:11:42 -0800119 which is contained in the 'debugfs' filesystem or procfs.
120 Thus, the debugfs or procfs filesystem must first be mounted before
121 making use of this feature.
Dave Hansen604ff0d2013-07-01 13:04:49 -0700122 We refer the control file as: <debugfs>/dynamic_debug/control. This
123 file contains a list of the debug statements that can be enabled. The
124 format for each line of the file is:
125
126 filename:lineno [module]function flags format
127
128 filename : source file of the debug statement
129 lineno : line number of the debug statement
130 module : module that contains the debug statement
131 function : function that contains the debug statement
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800132 flags : '=p' means the line is turned 'on' for printing
133 format : the format used for the debug statement
Dave Hansen604ff0d2013-07-01 13:04:49 -0700134
135 From a live system:
136
137 nullarbor:~ # cat <debugfs>/dynamic_debug/control
138 # filename:lineno [module]function flags format
139 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
140 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
141 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
142
143 Example usage:
144
145 // enable the message at line 1603 of file svcsock.c
146 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
147 <debugfs>/dynamic_debug/control
148
149 // enable all the messages in file svcsock.c
150 nullarbor:~ # echo -n 'file svcsock.c +p' >
151 <debugfs>/dynamic_debug/control
152
153 // enable all the messages in the NFS server module
154 nullarbor:~ # echo -n 'module nfsd +p' >
155 <debugfs>/dynamic_debug/control
156
157 // enable all 12 messages in the function svc_process()
158 nullarbor:~ # echo -n 'func svc_process +p' >
159 <debugfs>/dynamic_debug/control
160
161 // disable all 12 messages in the function svc_process()
162 nullarbor:~ # echo -n 'func svc_process -p' >
163 <debugfs>/dynamic_debug/control
164
Hans Holmbergf8998c22017-03-16 09:37:32 +0100165 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
166 information.
Dave Hansen604ff0d2013-07-01 13:04:49 -0700167
Rasmus Villemoes57f56772019-10-15 21:07:05 +0200168config SYMBOLIC_ERRNAME
169 bool "Support symbolic error names in printf"
170 default y if PRINTK
171 help
172 If you say Y here, the kernel's printf implementation will
173 be able to print symbolic error names such as ENOSPC instead
174 of the number 28. It makes the kernel image slightly larger
175 (about 3KB), but can make the kernel logs easier to read.
176
Changbin Du2b05bb72019-12-06 17:04:03 -0800177config DEBUG_BUGVERBOSE
178 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
179 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
180 default y
181 help
182 Say Y here to make BUG() panics output the file name and line number
183 of the BUG call as well as the EIP and oops trace. This aids
184 debugging but costs about 70-100K of memory.
185
Dave Hansen604ff0d2013-07-01 13:04:49 -0700186endmenu # "printk and dmesg options"
187
Dave Hansen6dfc0662013-07-01 13:04:46 -0700188menu "Compile-time checks and compiler options"
189
190config DEBUG_INFO
191 bool "Compile the kernel with debug info"
Linus Torvalds12b13832014-02-04 12:20:01 -0800192 depends on DEBUG_KERNEL && !COMPILE_TEST
Dave Hansen6dfc0662013-07-01 13:04:46 -0700193 help
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800194 If you say Y here the resulting kernel image will include
Dave Hansen6dfc0662013-07-01 13:04:46 -0700195 debugging info resulting in a larger kernel image.
196 This adds debug symbols to the kernel and modules (gcc -g), and
197 is needed if you intend to use kernel crashdump or binary object
198 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
199 Say Y here only if you plan to debug the kernel.
200
201 If unsure, say N.
202
203config DEBUG_INFO_REDUCED
204 bool "Reduce debugging information"
205 depends on DEBUG_INFO
206 help
207 If you say Y here gcc is instructed to generate less debugging
208 information for structure types. This means that tools that
209 need full debugging information (like kgdb or systemtap) won't
210 be happy. But if you merely need debugging information to
211 resolve line numbers there is no loss. Advantage is that
212 build directory object sizes shrink dramatically over a full
213 DEBUG_INFO build and compile times are reduced too.
214 Only works with newer gcc versions.
215
Andi Kleen866ced92014-07-30 20:50:18 +0200216config DEBUG_INFO_SPLIT
217 bool "Produce split debuginfo in .dwo files"
Arnd Bergmanna687a532018-03-07 23:30:54 +0100218 depends on DEBUG_INFO
Masahiro Yamada9d937442019-02-22 16:56:09 +0900219 depends on $(cc-option,-gsplit-dwarf)
Andi Kleen866ced92014-07-30 20:50:18 +0200220 help
221 Generate debug info into separate .dwo files. This significantly
222 reduces the build directory size for builds with DEBUG_INFO,
223 because it stores the information only once on disk in .dwo
224 files instead of multiple times in object files and executables.
225 In addition the debug information is also compressed.
226
227 Requires recent gcc (4.7+) and recent gdb/binutils.
228 Any tool that packages or reads debug information would need
229 to know about the .dwo files and include them.
230 Incompatible with older versions of ccache.
231
Andi Kleenbfaf2dd2014-07-30 20:50:19 +0200232config DEBUG_INFO_DWARF4
233 bool "Generate dwarf4 debuginfo"
234 depends on DEBUG_INFO
Masahiro Yamada9d937442019-02-22 16:56:09 +0900235 depends on $(cc-option,-gdwarf-4)
Andi Kleenbfaf2dd2014-07-30 20:50:19 +0200236 help
237 Generate dwarf4 debug info. This requires recent versions
238 of gcc and gdb. It makes the debug information larger.
239 But it significantly improves the success of resolving
240 variables in gdb on optimized code.
241
Andrii Nakryikoe83b9f52019-04-02 09:49:50 -0700242config DEBUG_INFO_BTF
243 bool "Generate BTF typeinfo"
244 depends on DEBUG_INFO
Slava Bacherikov7d32e692020-04-02 23:41:39 +0300245 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
246 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
Andrii Nakryikoe83b9f52019-04-02 09:49:50 -0700247 help
248 Generate deduplicated BTF type information from DWARF debug info.
249 Turning this on expects presence of pahole tool, which will convert
250 DWARF type info into equivalent deduplicated BTF type info.
251
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800252config GDB_SCRIPTS
253 bool "Provide GDB scripts for kernel debugging"
254 depends on DEBUG_INFO
255 help
256 This creates the required links to GDB helper scripts in the
257 build directory. If you load vmlinux into gdb, the helper
258 scripts will be automatically imported by gdb as well, and
259 additional functions are available to analyze a Linux kernel
Andreas Platschek700199b02016-12-14 15:05:40 -0800260 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
261 for further details.
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800262
Andrew Mortoncebc04b2006-08-14 22:43:18 -0700263config ENABLE_MUST_CHECK
264 bool "Enable __must_check logic"
265 default y
266 help
267 Enable the __must_check logic in the kernel build. Disable this to
268 suppress the "warning: ignoring return value of 'foo', declared with
269 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270
Andi Kleen35bb5b12008-02-22 15:15:03 +0100271config FRAME_WARN
Masahiro Yamadaa83e4ca2020-02-17 00:19:36 +0900272 int "Warn for stack frames larger than"
Andi Kleen35bb5b12008-02-22 15:15:03 +0100273 range 0 8192
Kees Cook0e07f662016-10-27 17:46:41 -0700274 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
Helge Deller432654d2017-09-11 21:41:43 +0200275 default 1280 if (!64BIT && PARISC)
276 default 1024 if (!64BIT && !PARISC)
Andi Kleen35bb5b12008-02-22 15:15:03 +0100277 default 2048 if 64BIT
278 help
279 Tell gcc to warn at build time for stack frames larger than this.
280 Setting this too low will cause a lot of warnings.
281 Setting it to 0 disables the warning.
Andi Kleen35bb5b12008-02-22 15:15:03 +0100282
Randy Dunlap99657c72009-09-18 12:49:22 -0700283config STRIP_ASM_SYMS
284 bool "Strip assembler-generated symbols during link"
285 default n
286 help
287 Strip internal assembler-generated symbols during a link (symbols
288 that look like '.Lxxx') so they don't pollute the output of
289 get_wchan() and suchlike.
290
Andi Kleen1873e872012-03-28 11:51:18 -0700291config READABLE_ASM
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800292 bool "Generate readable assembler code"
293 depends on DEBUG_KERNEL
Don Mullisbf4735a2006-12-10 02:18:37 -0800294 help
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800295 Disable some compiler optimizations that tend to generate human unreadable
296 assembler output. This may make the kernel slightly slower, but it helps
297 to keep kernel developers who have to stare a lot at assembler listings
298 sane.
Don Mullisbf4735a2006-12-10 02:18:37 -0800299
Masahiro Yamadae949f4c2019-06-04 19:13:59 +0900300config HEADERS_INSTALL
301 bool "Install uapi headers to usr/include"
Don Mullisbf4735a2006-12-10 02:18:37 -0800302 depends on !UML
303 help
Masahiro Yamadae949f4c2019-06-04 19:13:59 +0900304 This option will install uapi headers (headers exported to user-space)
305 into the usr/include directory for use during the kernel build.
306 This is unneeded for building the kernel itself, but needed for some
307 user-space program samples. It is also needed by some features such
308 as uapi header sanity checks.
309
Sam Ravnborg91341d42008-01-21 21:31:44 +0100310config DEBUG_SECTION_MISMATCH
311 bool "Enable full Section mismatch analysis"
Sam Ravnborg91341d42008-01-21 21:31:44 +0100312 help
313 The section mismatch analysis checks if there are illegal
314 references from one section to another section.
Michael Wittene809ab02011-04-17 04:08:48 +0000315 During linktime or runtime, some sections are dropped;
316 any use of code/data previously in these sections would
Sam Ravnborg91341d42008-01-21 21:31:44 +0100317 most likely result in an oops.
Michael Wittene809ab02011-04-17 04:08:48 +0000318 In the code, functions and variables are annotated with
Paul Gortmaker0db06282013-06-19 14:53:51 -0400319 __init,, etc. (see the full list in include/linux/init.h),
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100320 which results in the code/data being placed in specific sections.
Michael Wittene809ab02011-04-17 04:08:48 +0000321 The section mismatch analysis is always performed after a full
322 kernel build, and enabling this option causes the following
Masahiro Yamadab7dca6d2019-07-17 15:17:57 +0900323 additional step to occur:
Michael Wittene809ab02011-04-17 04:08:48 +0000324 - Add the option -fno-inline-functions-called-once to gcc commands.
325 When inlining a function annotated with __init in a non-init
326 function, we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100327 the analysis would not catch the illegal reference.
Michael Wittene809ab02011-04-17 04:08:48 +0000328 This option tells gcc to inline less (but it does result in
329 a larger kernel).
Sam Ravnborg91341d42008-01-21 21:31:44 +0100330
Nicolas Boichat47490ec2015-10-06 09:44:42 +1030331config SECTION_MISMATCH_WARN_ONLY
332 bool "Make section mismatch errors non-fatal"
333 default y
334 help
335 If you say N here, the build process will fail if there are any
336 section mismatch, instead of just throwing warnings.
337
338 If unsure, say Y.
339
Dave Hansen6dfc0662013-07-01 13:04:46 -0700340#
341# Select this config option from the architecture Kconfig, if it
342# is preferred to always offer frame pointers as a config
343# option on the architecture (regardless of KERNEL_DEBUG):
344#
345config ARCH_WANT_FRAME_POINTERS
346 bool
Dave Hansen6dfc0662013-07-01 13:04:46 -0700347
348config FRAME_POINTER
349 bool "Compile the kernel with frame pointers"
Arnd Bergmanna687a532018-03-07 23:30:54 +0100350 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
Dave Hansen6dfc0662013-07-01 13:04:46 -0700351 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
352 help
353 If you say Y here the resulting kernel image will be slightly
354 larger and slower, but it gives very useful debugging information
355 in case of kernel bugs. (precise oopses/stacktraces/warnings)
356
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600357config STACK_VALIDATION
358 bool "Compile-time stack metadata validation"
359 depends on HAVE_STACK_VALIDATION
360 default n
361 help
362 Add compile-time checks to validate stack metadata, including frame
363 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
364 that runtime stack traces are more reliable.
365
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500366 This is also a prerequisite for generation of ORC unwind data, which
Josh Poimboeuf11af8472017-10-13 15:02:00 -0500367 is needed for CONFIG_UNWINDER_ORC.
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500368
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600369 For more information, see
370 tools/objtool/Documentation/stack-validation.txt.
371
Dave Hansen6dfc0662013-07-01 13:04:46 -0700372config DEBUG_FORCE_WEAK_PER_CPU
373 bool "Force weak per-cpu definitions"
374 depends on DEBUG_KERNEL
375 help
376 s390 and alpha require percpu variables in modules to be
377 defined weak to work around addressing range issue which
378 puts the following two restrictions on percpu variable
379 definitions.
380
381 1. percpu symbols must be unique whether static or not
382 2. percpu variables can't be defined inside a function
383
384 To ensure that generic code follows the above rules, this
385 option forces all percpu variables to be defined as weak.
386
387endmenu # "Compiler options"
388
Changbin Du6210b642019-12-06 17:03:42 -0800389menu "Generic Kernel Debugging Instruments"
390
Dave Hansen6dfc0662013-07-01 13:04:46 -0700391config MAGIC_SYSRQ
392 bool "Magic SysRq key"
393 depends on !UML
394 help
395 If you say Y here, you will have some control over the system even
396 if the system crashes for example during kernel debugging (e.g., you
397 will be able to flush the buffer cache to disk, reboot the system
398 immediately or dump some status information). This is accomplished
399 by pressing various keys while holding SysRq (Alt+PrintScreen). It
400 also works on a serial console (on PC hardware at least), if you
401 send a BREAK and then within 5 seconds a command keypress. The
Hans Holmbergf8998c22017-03-16 09:37:32 +0100402 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
403 Don't say Y unless you really know what this hack does.
Dave Hansen6dfc0662013-07-01 13:04:46 -0700404
Ben Hutchings8eaede42013-10-07 01:05:46 +0100405config MAGIC_SYSRQ_DEFAULT_ENABLE
406 hex "Enable magic SysRq key functions by default"
407 depends on MAGIC_SYSRQ
408 default 0x1
409 help
410 Specifies which SysRq key functions are enabled by default.
411 This may be set to 1 or 0 to enable or disable them all, or
Hans Holmbergf8998c22017-03-16 09:37:32 +0100412 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
Ben Hutchings8eaede42013-10-07 01:05:46 +0100413
Felix Fietkau732dbf32016-12-22 08:31:34 +0100414config MAGIC_SYSRQ_SERIAL
415 bool "Enable magic SysRq key over serial"
416 depends on MAGIC_SYSRQ
417 default y
418 help
419 Many embedded boards have a disconnected TTL level serial which can
420 generate some garbage that can lead to spurious false sysrq detects.
421 This option allows you to decide whether you want to enable the
422 magic SysRq key.
423
Dmitry Safonov68af4312020-03-02 17:51:35 +0000424config MAGIC_SYSRQ_SERIAL_SEQUENCE
425 string "Char sequence that enables magic SysRq over serial"
426 depends on MAGIC_SYSRQ_SERIAL
427 default ""
428 help
429 Specifies a sequence of characters that can follow BREAK to enable
430 SysRq on a serial console.
431
Dmitry Safonovd3394b32020-03-06 15:31:56 +0000432 If unsure, leave an empty string and the option will not be enabled.
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
Konstantin Khlebnikov30428ef2020-04-06 20:09:47 -0700981config TEST_LOCKUP
982 tristate "Test module to generate lockups"
983 help
984 This builds the "test_lockup" module that helps to make sure
985 that watchdogs and lockup detectors are working properly.
986
987 Depending on module parameters it could emulate soft or hard
988 lockup, "hung task", or locking arbitrary lock for a long time.
989 Also it could generate series of lockups with cooling-down periods.
990
991 If unsure, say N.
992
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700993endmenu # "Debug lockups and hangs"
994
Changbin Duebebdd02019-12-06 17:04:00 -0800995menu "Scheduler Debugging"
Jason Baron5800dc32013-11-25 23:23:04 +0000996
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997config SCHED_DEBUG
998 bool "Collect scheduler debugging info"
999 depends on DEBUG_KERNEL && PROC_FS
1000 default y
1001 help
1002 If you say Y here, the /proc/sched_debug file will be provided
1003 that can help debug the scheduler. The runtime overhead of this
1004 option is minimal.
1005
Naveen N. Raof6db8342015-06-25 23:53:37 +05301006config SCHED_INFO
1007 bool
1008 default n
1009
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010config SCHEDSTATS
1011 bool "Collect scheduler statistics"
1012 depends on DEBUG_KERNEL && PROC_FS
Naveen N. Raof6db8342015-06-25 23:53:37 +05301013 select SCHED_INFO
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 help
1015 If you say Y here, additional code will be inserted into the
1016 scheduler and related routines to collect statistics about
1017 scheduler behavior and provide them in /proc/schedstat. These
1018 stats may be useful for both tuning and debugging the scheduler
1019 If you aren't debugging the scheduler or trying to tune a specific
1020 application, you can say N to avoid the very slight overhead
1021 this adds.
1022
Changbin Duebebdd02019-12-06 17:04:00 -08001023endmenu
Aaron Tomlin0d9e2632014-09-12 14:16:19 +01001024
John Stultz3c17ad12015-03-11 21:16:32 -07001025config DEBUG_TIMEKEEPING
1026 bool "Enable extra timekeeping sanity checking"
1027 help
1028 This option will enable additional timekeeping sanity checks
1029 which may be helpful when diagnosing issues where timekeeping
1030 problems are suspected.
1031
1032 This may include checks in the timekeeping hotpaths, so this
1033 option may have a (very small) performance impact to some
1034 workloads.
1035
1036 If unsure, say N.
1037
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038config DEBUG_PREEMPT
1039 bool "Debug preemptible kernel"
Sebastian Andrzej Siewior9f472862019-10-15 21:18:19 +02001040 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001041 default y
1042 help
1043 If you say Y here then the kernel will use a debug variant of the
1044 commonly used smp_processor_id() function and will print warnings
1045 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1046 will detect preemption count underflows.
1047
Dave Hansen9eade162013-07-01 13:04:47 -07001048menu "Lock Debugging (spinlocks, mutexes, etc...)"
1049
Waiman Longf07cbeb2018-03-30 17:27:59 -04001050config LOCK_DEBUGGING_SUPPORT
1051 bool
1052 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1053 default y
1054
Waiman Long19193bc2018-03-30 17:28:00 -04001055config PROVE_LOCKING
1056 bool "Lock debugging: prove locking correctness"
1057 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1058 select LOCKDEP
1059 select DEBUG_SPINLOCK
1060 select DEBUG_MUTEXES
1061 select DEBUG_RT_MUTEXES if RT_MUTEXES
Waiman Longc71fd892019-05-20 16:59:00 -04001062 select DEBUG_RWSEMS
Waiman Long19193bc2018-03-30 17:28:00 -04001063 select DEBUG_WW_MUTEX_SLOWPATH
1064 select DEBUG_LOCK_ALLOC
1065 select TRACE_IRQFLAGS
1066 default n
1067 help
1068 This feature enables the kernel to prove that all locking
1069 that occurs in the kernel runtime is mathematically
1070 correct: that under no circumstance could an arbitrary (and
1071 not yet triggered) combination of observed locking
1072 sequences (on an arbitrary number of CPUs, running an
1073 arbitrary number of tasks and interrupt contexts) cause a
1074 deadlock.
1075
1076 In short, this feature enables the kernel to report locking
1077 related deadlocks before they actually occur.
1078
1079 The proof does not depend on how hard and complex a
1080 deadlock scenario would be to trigger: how many
1081 participant CPUs, tasks and irq-contexts would be needed
1082 for it to trigger. The proof also does not depend on
1083 timing: if a race and a resulting deadlock is possible
1084 theoretically (no matter how unlikely the race scenario
1085 is), it will be proven so and will immediately be
1086 reported by the kernel (once the event is observed that
1087 makes the deadlock theoretically possible).
1088
1089 If a deadlock is impossible (i.e. the locking rules, as
1090 observed by the kernel, are mathematically correct), the
1091 kernel reports nothing.
1092
1093 NOTE: this feature can also be enabled for rwlocks, mutexes
1094 and rwsems - in which case all dependencies between these
1095 different locking variants are observed and mapped too, and
1096 the proof of observed correctness is also maintained for an
1097 arbitrary combination of these separate locking variants.
1098
Mauro Carvalho Chehab387b1462019-04-10 08:32:41 -03001099 For more details, see Documentation/locking/lockdep-design.rst.
Waiman Long19193bc2018-03-30 17:28:00 -04001100
Peter Zijlstrade8f5e42020-03-21 12:26:01 +01001101config PROVE_RAW_LOCK_NESTING
1102 bool "Enable raw_spinlock - spinlock nesting checks"
1103 depends on PROVE_LOCKING
1104 default n
1105 help
1106 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1107 that the lock nesting rules for PREEMPT_RT enabled kernels are
1108 not violated.
1109
1110 NOTE: There are known nesting problems. So if you enable this
1111 option expect lockdep splats until these problems have been fully
1112 addressed which is work in progress. This config switch allows to
1113 identify and analyze these problems. It will be removed and the
1114 check permanentely enabled once the main issues have been fixed.
1115
1116 If unsure, select N.
1117
Waiman Long19193bc2018-03-30 17:28:00 -04001118config LOCK_STAT
1119 bool "Lock usage statistics"
1120 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1121 select LOCKDEP
1122 select DEBUG_SPINLOCK
1123 select DEBUG_MUTEXES
1124 select DEBUG_RT_MUTEXES if RT_MUTEXES
1125 select DEBUG_LOCK_ALLOC
1126 default n
1127 help
1128 This feature enables tracking lock contention points
1129
Mauro Carvalho Chehab387b1462019-04-10 08:32:41 -03001130 For more details, see Documentation/locking/lockstat.rst
Waiman Long19193bc2018-03-30 17:28:00 -04001131
1132 This also enables lock events required by "perf lock",
1133 subcommand of perf.
1134 If you want to use "perf lock", you also need to turn on
1135 CONFIG_EVENT_TRACING.
1136
1137 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1138 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1139
Linus Torvalds1da177e2005-04-16 15:20:36 -07001140config DEBUG_RT_MUTEXES
1141 bool "RT Mutex debugging, deadlock detection"
1142 depends on DEBUG_KERNEL && RT_MUTEXES
1143 help
1144 This allows rt mutex semantics violations and rt mutex related
1145 deadlocks (lockups) to be detected and reported automatically.
1146
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001148 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +05301150 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151 help
1152 Say Y here and build SMP to catch missing spinlock initialization
1153 and certain other kinds of spinlock errors commonly made. This is
1154 best used in conjunction with the NMI watchdog so that spinlock
1155 deadlocks are also debuggable.
1156
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001157config DEBUG_MUTEXES
1158 bool "Mutex debugging: basic checks"
1159 depends on DEBUG_KERNEL
1160 help
1161 This feature allows mutex semantics violations to be detected and
1162 reported.
1163
Daniel Vetter23010022013-06-20 13:31:17 +02001164config DEBUG_WW_MUTEX_SLOWPATH
1165 bool "Wait/wound mutex debugging: Slowpath testing"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001166 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Daniel Vetter23010022013-06-20 13:31:17 +02001167 select DEBUG_LOCK_ALLOC
1168 select DEBUG_SPINLOCK
1169 select DEBUG_MUTEXES
1170 help
1171 This feature enables slowpath testing for w/w mutex users by
1172 injecting additional -EDEADLK wound/backoff cases. Together with
1173 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1174 will test all possible w/w mutex interface abuse with the
1175 exception of simply not acquiring all the required locks.
Rob Clark4d692372014-08-27 11:19:26 -04001176 Note that this feature can introduce significant overhead, so
1177 it really should not be enabled in a production or distro kernel,
1178 even a debug kernel. If you are a driver writer, enable it. If
1179 you are a distro, do not.
Daniel Vetter23010022013-06-20 13:31:17 +02001180
Waiman Long5149cba2018-03-30 17:27:58 -04001181config DEBUG_RWSEMS
1182 bool "RW Semaphore debugging: basic checks"
Waiman Longc71fd892019-05-20 16:59:00 -04001183 depends on DEBUG_KERNEL
Waiman Long5149cba2018-03-30 17:27:58 -04001184 help
Waiman Longc71fd892019-05-20 16:59:00 -04001185 This debugging feature allows mismatched rw semaphore locks
1186 and unlocks to be detected and reported.
Waiman Long5149cba2018-03-30 17:27:58 -04001187
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001188config DEBUG_LOCK_ALLOC
1189 bool "Lock debugging: detect incorrect freeing of live locks"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001190 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001191 select DEBUG_SPINLOCK
1192 select DEBUG_MUTEXES
Peter Zijlstraf5694782016-09-19 12:15:37 +02001193 select DEBUG_RT_MUTEXES if RT_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001194 select LOCKDEP
1195 help
1196 This feature will check whether any held lock (spinlock, rwlock,
1197 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1198 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1199 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1200 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1201 held during task exit.
1202
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001203config LOCKDEP
1204 bool
Waiman Longf07cbeb2018-03-30 17:27:59 -04001205 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001206 select STACKTRACE
Stefan Agnerf9b58e82018-09-30 23:02:33 +01001207 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001208 select KALLSYMS
1209 select KALLSYMS_ALL
1210
Daniel Jordan395102d2017-04-10 11:50:52 -04001211config LOCKDEP_SMALL
1212 bool
1213
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001214config DEBUG_LOCKDEP
1215 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -07001216 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001217 help
1218 If you say Y here, the lock dependency engine will do
1219 additional runtime checks to debug itself, at the price
1220 of more runtime overhead.
1221
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001222config DEBUG_ATOMIC_SLEEP
1223 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +02001224 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225 depends on DEBUG_KERNEL
Christoph Hellwig87a4c372018-07-31 13:39:32 +02001226 depends on !ARCH_NO_PREEMPT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001227 help
1228 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001229 noisy if they are called inside atomic sections: when a spinlock is
1230 held, inside an rcu read side critical section, inside preempt disabled
1231 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -07001232
Ingo Molnarcae2ed92006-07-03 00:24:48 -07001233config DEBUG_LOCKING_API_SELFTESTS
1234 bool "Locking API boot-time self-tests"
1235 depends on DEBUG_KERNEL
1236 help
1237 Say Y here if you want the kernel to run a short self-test during
1238 bootup. The self-test checks whether common types of locking bugs
1239 are detected by debugging mechanisms or not. (if you disable
1240 lock debugging then those bugs wont be detected of course.)
1241 The following locking APIs are covered: spinlocks, rwlocks,
1242 mutexes and rwsems.
1243
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001244config LOCK_TORTURE_TEST
1245 tristate "torture tests for locking"
1246 depends on DEBUG_KERNEL
1247 select TORTURE_TEST
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001248 help
1249 This option provides a kernel module that runs torture tests
1250 on kernel locking primitives. The kernel module may be built
1251 after the fact on the running kernel to be tested, if desired.
1252
1253 Say Y here if you want kernel locking-primitive torture tests
1254 to be built into the kernel.
1255 Say M if you want these torture tests to build as a module.
1256 Say N if you are unsure.
1257
Chris Wilsonf2a5fec2016-12-01 11:47:06 +00001258config WW_MUTEX_SELFTEST
1259 tristate "Wait/wound mutex selftests"
1260 help
1261 This option provides a kernel module that runs tests on the
1262 on the struct ww_mutex locking API.
1263
1264 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1265 with this test harness.
1266
1267 Say M if you want these self tests to build as a module.
1268 Say N if you are unsure.
1269
Dave Hansen9eade162013-07-01 13:04:47 -07001270endmenu # lock debugging
1271
1272config TRACE_IRQFLAGS
1273 bool
1274 help
1275 Enables hooks to interrupt enabling and disabling for
1276 either tracing or lock debugging.
1277
Ingo Molnar8637c092006-07-03 00:24:38 -07001278config STACKTRACE
Dave Jones0c38e1f2014-08-29 15:18:35 -07001279 bool "Stack backtrace support"
Ingo Molnar8637c092006-07-03 00:24:38 -07001280 depends on STACKTRACE_SUPPORT
Dave Jones0c38e1f2014-08-29 15:18:35 -07001281 help
1282 This option causes the kernel to create a /proc/pid/stack for
1283 every process, showing its current stack trace.
1284 It is also used by various kernel debugging features that require
1285 stack trace generation.
Ingo Molnar8637c092006-07-03 00:24:38 -07001286
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001287config WARN_ALL_UNSEEDED_RANDOM
1288 bool "Warn for all uses of unseeded randomness"
1289 default n
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001290 help
1291 Some parts of the kernel contain bugs relating to their use of
1292 cryptographically secure random numbers before it's actually possible
1293 to generate those numbers securely. This setting ensures that these
1294 flaws don't go unnoticed, by enabling a message, should this ever
1295 occur. This will allow people with obscure setups to know when things
1296 are going wrong, so that they might contact developers about fixing
1297 it.
1298
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001299 Unfortunately, on some models of some architectures getting
1300 a fully seeded CRNG is extremely difficult, and so this can
1301 result in dmesg getting spammed for a surprisingly long
1302 time. This is really bad from a security perspective, and
1303 so architecture maintainers really need to do what they can
1304 to get the CRNG seeded sooner after the system is booted.
Thibaut Sautereau4c5d1142018-09-04 15:46:23 -07001305 However, since users cannot do anything actionable to
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001306 address this, by default the kernel will issue only a single
1307 warning for the first use of unseeded randomness.
1308
1309 Say Y here if you want to receive warnings for all uses of
1310 unseeded randomness. This will be of use primarily for
Thibaut Sautereau4c5d1142018-09-04 15:46:23 -07001311 those developers interested in improving the security of
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001312 Linux kernels running on their architecture (or
1313 subarchitecture).
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001314
Linus Torvalds1da177e2005-04-16 15:20:36 -07001315config DEBUG_KOBJECT
1316 bool "kobject debugging"
1317 depends on DEBUG_KERNEL
1318 help
1319 If you say Y here, some extra kobject debugging messages will be sent
Mike Rapoportaca52c32018-10-30 15:07:44 -07001320 to the syslog.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321
Russell Kingc817a672013-06-27 15:06:14 +01001322config DEBUG_KOBJECT_RELEASE
1323 bool "kobject release debugging"
Linus Torvalds2a999aa2013-10-29 08:33:36 -07001324 depends on DEBUG_OBJECTS_TIMERS
Russell Kingc817a672013-06-27 15:06:14 +01001325 help
1326 kobjects are reference counted objects. This means that their
1327 last reference count put is not predictable, and the kobject can
1328 live on past the point at which a driver decides to drop it's
1329 initial reference to the kobject gained on allocation. An
1330 example of this would be a struct device which has just been
1331 unregistered.
1332
1333 However, some buggy drivers assume that after such an operation,
1334 the memory backing the kobject can be immediately freed. This
1335 goes completely against the principles of a refcounted object.
1336
1337 If you say Y here, the kernel will delay the release of kobjects
1338 on the last reference count to improve the visibility of this
1339 kind of kobject release bug.
1340
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001341config HAVE_DEBUG_BUGVERBOSE
1342 bool
1343
Changbin Du3be5cbc2019-12-06 17:03:48 -08001344menu "Debug kernel data structures"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001345
Dave Jones199a9af2006-09-29 01:59:00 -07001346config DEBUG_LIST
1347 bool "Debug linked list manipulation"
Arnd Bergmann4520bcb2016-08-26 17:42:00 +02001348 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
Dave Jones199a9af2006-09-29 01:59:00 -07001349 help
1350 Enable this to turn on extended checks in the linked-list
1351 walking routines.
1352
1353 If unsure, say N.
1354
Davidlohr Bueso8e18fae2019-05-14 15:42:46 -07001355config DEBUG_PLIST
Dan Streetmanb8cfff62014-06-04 16:11:54 -07001356 bool "Debug priority linked list manipulation"
1357 depends on DEBUG_KERNEL
1358 help
1359 Enable this to turn on extended checks in the priority-ordered
1360 linked-list (plist) walking routines. This checks the entire
1361 list multiple times during each manipulation.
1362
1363 If unsure, say N.
1364
Jens Axboed6ec0842007-10-22 20:01:06 +02001365config DEBUG_SG
1366 bool "Debug SG table operations"
1367 depends on DEBUG_KERNEL
1368 help
1369 Enable this to turn on checks on scatter-gather tables. This can
1370 help find problems with drivers that do not properly initialize
1371 their sg tables.
1372
1373 If unsure, say N.
1374
Arjan van de Ven1b2439d2008-08-15 15:29:38 -07001375config DEBUG_NOTIFIERS
1376 bool "Debug notifier call chains"
1377 depends on DEBUG_KERNEL
1378 help
1379 Enable this to turn on sanity checking for notifier call chains.
1380 This is most useful for kernel developers to make sure that
1381 modules properly unregister themselves from notifier chains.
1382 This is a relatively cheap check but if you care about maximum
1383 performance, say N.
1384
Changbin Du3be5cbc2019-12-06 17:03:48 -08001385config BUG_ON_DATA_CORRUPTION
1386 bool "Trigger a BUG when data corruption is detected"
1387 select DEBUG_LIST
1388 help
1389 Select this option if the kernel should BUG when it encounters
1390 data corruption in kernel memory structures when they get checked
1391 for validity.
1392
1393 If unsure, say N.
1394
1395endmenu
1396
David Howellse0e81732009-09-02 09:13:40 +01001397config DEBUG_CREDENTIALS
1398 bool "Debug credential management"
1399 depends on DEBUG_KERNEL
1400 help
1401 Enable this to turn on some debug checking for credential
1402 management. The additional code keeps track of the number of
1403 pointers from task_structs to any given cred struct, and checks to
1404 see that this number never exceeds the usage count of the cred
1405 struct.
1406
1407 Furthermore, if SELinux is enabled, this also checks that the
1408 security pointer in the cred struct is never seen to be invalid.
1409
1410 If unsure, say N.
1411
Paul E. McKenney43a0a2a2017-05-17 09:19:44 -07001412source "kernel/rcu/Kconfig.debug"
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001413
Tejun Heof303fccb2016-02-09 17:59:38 -05001414config DEBUG_WQ_FORCE_RR_CPU
1415 bool "Force round-robin CPU selection for unbound work items"
1416 depends on DEBUG_KERNEL
1417 default n
1418 help
1419 Workqueue used to implicitly guarantee that work items queued
1420 without explicit CPU specified are put on the local CPU. This
1421 guarantee is no longer true and while local CPU is still
1422 preferred work items may be put on foreign CPUs. Kernel
1423 parameter "workqueue.debug_force_rr_cpu" is added to force
1424 round-robin CPU selection to flush out usages which depend on the
1425 now broken guarantee. This config option enables the debug
1426 feature by default. When enabled, memory and cache locality will
1427 be impacted.
1428
Tejun Heo870d6652008-08-25 19:47:25 +09001429config DEBUG_BLOCK_EXT_DEVT
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -08001430 bool "Force extended block device numbers and spread them"
Tejun Heo870d6652008-08-25 19:47:25 +09001431 depends on DEBUG_KERNEL
1432 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +02001433 default n
Tejun Heo870d6652008-08-25 19:47:25 +09001434 help
Tejun Heo0e11e342008-10-13 10:46:01 +02001435 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1436 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1437 YOU ARE DOING. Distros, please enable this and fix whatever
1438 is broken.
1439
Tejun Heo870d6652008-08-25 19:47:25 +09001440 Conventionally, block device numbers are allocated from
1441 predetermined contiguous area. However, extended block area
1442 may introduce non-contiguous block device numbers. This
1443 option forces most block device numbers to be allocated from
1444 the extended space and spreads them to discover kernel or
1445 userland code paths which assume predetermined contiguous
1446 device number allocation.
1447
Tejun Heo55dc7db2008-09-01 13:44:35 +02001448 Note that turning on this debug option shuffles all the
1449 device numbers for all IDE and SCSI devices including libata
1450 ones, so root partition specified using device number
1451 directly (via rdev or root=MAJ:MIN) won't work anymore.
1452 Textual device names (root=/dev/sdXn) will continue to work.
1453
Tejun Heo870d6652008-08-25 19:47:25 +09001454 Say N if you are unsure.
1455
Thomas Gleixner757c9892016-02-26 18:43:32 +00001456config CPU_HOTPLUG_STATE_CONTROL
1457 bool "Enable CPU hotplug state control"
1458 depends on DEBUG_KERNEL
1459 depends on HOTPLUG_CPU
1460 default n
1461 help
1462 Allows to write steps between "offline" and "online" to the CPUs
1463 sysfs target file so states can be stepped granular. This is a debug
1464 option for now as the hotplug machinery cannot be stopped and
1465 restarted at arbitrary points yet.
1466
1467 Say N if your are unsure.
1468
Changbin Du09a74952019-12-06 17:03:51 -08001469config LATENCYTOP
1470 bool "Latency measuring infrastructure"
1471 depends on DEBUG_KERNEL
1472 depends on STACKTRACE_SUPPORT
1473 depends on PROC_FS
1474 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1475 select KALLSYMS
1476 select KALLSYMS_ALL
1477 select STACKTRACE
1478 select SCHEDSTATS
1479 select SCHED_DEBUG
1480 help
1481 Enable this option if you want to use the LatencyTOP tool
1482 to find out which userspace is blocking on what kernel operations.
1483
1484source "kernel/trace/Kconfig"
1485
1486config PROVIDE_OHCI1394_DMA_INIT
1487 bool "Remote debugging over FireWire early on boot"
1488 depends on PCI && X86
1489 help
1490 If you want to debug problems which hang or crash the kernel early
1491 on boot and the crashing machine has a FireWire port, you can use
1492 this feature to remotely access the memory of the crashed machine
1493 over FireWire. This employs remote DMA as part of the OHCI1394
1494 specification which is now the standard for FireWire controllers.
1495
1496 With remote DMA, you can monitor the printk buffer remotely using
1497 firescope and access all memory below 4GB using fireproxy from gdb.
1498 Even controlling a kernel debugger is possible using remote DMA.
1499
1500 Usage:
1501
1502 If ohci1394_dma=early is used as boot parameter, it will initialize
1503 all OHCI1394 controllers which are found in the PCI config space.
1504
1505 As all changes to the FireWire bus such as enabling and disabling
1506 devices cause a bus reset and thereby disable remote DMA for all
1507 devices, be sure to have the cable plugged and FireWire enabled on
1508 the debugging host before booting the debug target for debugging.
1509
1510 This code (~1k) is freed after boot. By then, the firewire stack
1511 in charge of the OHCI-1394 controllers should be used instead.
1512
1513 See Documentation/debugging-via-ohci1394.txt for more information.
1514
Changbin Du045f6d72019-12-17 20:51:56 -08001515source "samples/Kconfig"
1516
1517config ARCH_HAS_DEVMEM_IS_ALLOWED
1518 bool
1519
1520config STRICT_DEVMEM
1521 bool "Filter access to /dev/mem"
1522 depends on MMU && DEVMEM
1523 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
1524 default y if PPC || X86 || ARM64
1525 help
1526 If this option is disabled, you allow userspace (root) access to all
1527 of memory, including kernel and userspace memory. Accidental
1528 access to this is obviously disastrous, but specific access can
1529 be used by people debugging the kernel. Note that with PAT support
1530 enabled, even in this case there are restrictions on /dev/mem
1531 use due to the cache aliasing requirements.
1532
1533 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1534 file only allows userspace access to PCI space and the BIOS code and
1535 data regions. This is sufficient for dosemu and X and all common
1536 users of /dev/mem.
1537
1538 If in doubt, say Y.
1539
1540config IO_STRICT_DEVMEM
1541 bool "Filter I/O access to /dev/mem"
1542 depends on STRICT_DEVMEM
1543 help
1544 If this option is disabled, you allow userspace (root) access to all
1545 io-memory regardless of whether a driver is actively using that
1546 range. Accidental access to this is obviously disastrous, but
1547 specific access can be used by people debugging kernel drivers.
1548
1549 If this option is switched on, the /dev/mem file only allows
1550 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1551 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1552 if the driver using a given range cannot be disabled.
1553
1554 If in doubt, say Y.
1555
1556menu "$(SRCARCH) Debugging"
1557
1558source "arch/$(SRCARCH)/Kconfig.debug"
1559
1560endmenu
1561
1562menu "Kernel Testing and Coverage"
1563
Changbin Du09a74952019-12-06 17:03:51 -08001564source "lib/kunit/Kconfig"
1565
Akinobu Mita8d438282012-07-30 14:43:02 -07001566config NOTIFIER_ERROR_INJECTION
1567 tristate "Notifier error injection"
1568 depends on DEBUG_KERNEL
1569 select DEBUG_FS
1570 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001571 This option provides the ability to inject artificial errors to
Akinobu Mita8d438282012-07-30 14:43:02 -07001572 specified notifier chain callbacks. It is useful to test the error
1573 handling of notifier call chain failures.
1574
1575 Say N if unsure.
1576
Akinobu Mita048b9c32012-07-30 14:43:07 -07001577config PM_NOTIFIER_ERROR_INJECT
1578 tristate "PM notifier error injection module"
1579 depends on PM && NOTIFIER_ERROR_INJECTION
1580 default m if PM_DEBUG
1581 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001582 This option provides the ability to inject artificial errors to
Akinobu Mita048b9c32012-07-30 14:43:07 -07001583 PM notifier chain callbacks. It is controlled through debugfs
1584 interface /sys/kernel/debug/notifier-error-inject/pm
1585
1586 If the notifier call chain should be failed with some events
1587 notified, write the error code to "actions/<notifier event>/error".
1588
1589 Example: Inject PM suspend error (-12 = -ENOMEM)
1590
1591 # cd /sys/kernel/debug/notifier-error-inject/pm/
1592 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1593 # echo mem > /sys/power/state
1594 bash: echo: write error: Cannot allocate memory
1595
1596 To compile this code as a module, choose M here: the module will
1597 be called pm-notifier-error-inject.
1598
1599 If unsure, say N.
1600
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001601config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1602 tristate "OF reconfig notifier error injection module"
1603 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001604 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001605 This option provides the ability to inject artificial errors to
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001606 OF reconfig notifier chain callbacks. It is controlled
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001607 through debugfs interface under
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001608 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001609
1610 If the notifier call chain should be failed with some events
1611 notified, write the error code to "actions/<notifier event>/error".
1612
1613 To compile this code as a module, choose M here: the module will
Akinobu Mitae12a95f2013-04-30 15:28:49 -07001614 be called of-reconfig-notifier-error-inject.
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001615
1616 If unsure, say N.
1617
Nikolay Aleksandrov02fff962015-11-28 13:45:28 +01001618config NETDEV_NOTIFIER_ERROR_INJECT
1619 tristate "Netdev notifier error injection module"
1620 depends on NET && NOTIFIER_ERROR_INJECTION
1621 help
1622 This option provides the ability to inject artificial errors to
1623 netdevice notifier chain callbacks. It is controlled through debugfs
1624 interface /sys/kernel/debug/notifier-error-inject/netdev
1625
1626 If the notifier call chain should be failed with some events
1627 notified, write the error code to "actions/<notifier event>/error".
1628
1629 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1630
1631 # cd /sys/kernel/debug/notifier-error-inject/netdev
1632 # echo -22 > actions/NETDEV_CHANGEMTU/error
1633 # ip link set eth0 mtu 1024
1634 RTNETLINK answers: Invalid argument
1635
1636 To compile this code as a module, choose M here: the module will
1637 be called netdev-notifier-error-inject.
1638
1639 If unsure, say N.
1640
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001641config FUNCTION_ERROR_INJECTION
1642 def_bool y
1643 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1644
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001645config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001646 bool "Fault-injection framework"
1647 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001648 help
1649 Provide fault-injection framework.
1650 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001651
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001652config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001653 bool "Fault-injection capability for kmalloc"
1654 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001655 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001656 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001657 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001658
Akinobu Mita933e3122006-12-08 02:39:45 -08001659config FAIL_PAGE_ALLOC
Qiujun Huang29b46fa2020-04-06 20:12:49 -07001660 bool "Fault-injection capability for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001661 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001662 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001663 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001664
Akinobu Mitac17bb492006-12-08 02:39:46 -08001665config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001666 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001667 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001668 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001669 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001670
Jens Axboe581d4e22008-09-14 05:56:33 -07001671config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d01432010-07-21 16:05:53 +09001672 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001673 depends on FAULT_INJECTION && BLOCK
1674 help
1675 Provide fault-injection capability on end IO handling. This
1676 will make the block layer "forget" an interrupt as configured,
1677 thus exercising the error handling.
1678
1679 Only works with drivers that use the generic timeout handling,
1680 for others it wont do anything.
1681
Davidlohr Buesoab51fba2015-06-29 23:26:02 -07001682config FAIL_FUTEX
1683 bool "Fault-injection capability for futexes"
1684 select DEBUG_FS
1685 depends on FAULT_INJECTION && FUTEX
1686 help
1687 Provide fault-injection capability for futexes.
1688
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001689config FAULT_INJECTION_DEBUG_FS
1690 bool "Debugfs entries for fault-injection capabilities"
1691 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1692 help
1693 Enable configuration of fault-injection capabilities via debugfs.
1694
Masami Hiramatsu4b1a29a2018-01-13 02:56:03 +09001695config FAIL_FUNCTION
1696 bool "Fault-injection capability for functions"
1697 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1698 help
1699 Provide function-based fault-injection capability.
1700 This will allow you to override a specific function with a return
1701 with given return value. As a result, function caller will see
1702 an error value and have to handle it. This is useful to test the
1703 error handling in various subsystems.
1704
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001705config FAIL_MMC_REQUEST
1706 bool "Fault-injection capability for MMC IO"
1707 depends on FAULT_INJECTION_DEBUG_FS && MMC
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001708 help
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001709 Provide fault-injection capability for MMC IO.
1710 This will make the mmc core return data errors. This is
1711 useful to test the error handling in the mmc block device
1712 and to test how the mmc host driver handles retries from
1713 the block device.
Akinobu Mita1df49002007-02-20 13:57:56 -08001714
1715config FAULT_INJECTION_STACKTRACE_FILTER
1716 bool "stacktrace filter for fault-injection capabilities"
1717 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001718 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001719 select STACKTRACE
Stefan Agnerf9b58e82018-09-30 23:02:33 +01001720 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
Akinobu Mita1df49002007-02-20 13:57:56 -08001721 help
1722 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001723
Changbin Du09a74952019-12-06 17:03:51 -08001724config ARCH_HAS_KCOV
1725 bool
Arjan van de Ven97455122008-01-25 21:08:34 +01001726 help
Changbin Du09a74952019-12-06 17:03:51 -08001727 An architecture should select this when it can successfully
1728 build and run with CONFIG_KCOV. This typically requires
1729 disabling instrumentation for some early boot code.
Arjan van de Ven97455122008-01-25 21:08:34 +01001730
Changbin Du09a74952019-12-06 17:03:51 -08001731config CC_HAS_SANCOV_TRACE_PC
1732 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001733
Changbin Du09a74952019-12-06 17:03:51 -08001734
1735config KCOV
1736 bool "Code coverage for fuzzing"
1737 depends on ARCH_HAS_KCOV
1738 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1739 select DEBUG_FS
1740 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001741 help
Changbin Du09a74952019-12-06 17:03:51 -08001742 KCOV exposes kernel code coverage information in a form suitable
1743 for coverage-guided fuzzing (randomized testing).
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001744
Changbin Du09a74952019-12-06 17:03:51 -08001745 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1746 different machines and across reboots. If you need stable PC values,
1747 disable RANDOMIZE_BASE.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001748
Changbin Du09a74952019-12-06 17:03:51 -08001749 For more details, see Documentation/dev-tools/kcov.rst.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001750
Changbin Du09a74952019-12-06 17:03:51 -08001751config KCOV_ENABLE_COMPARISONS
1752 bool "Enable comparison operands collection by KCOV"
1753 depends on KCOV
1754 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1755 help
1756 KCOV also exposes operands of every comparison in the instrumented
1757 code along with operand sizes and PCs of the comparison instructions.
1758 These operands can be used by fuzzing engines to improve the quality
1759 of fuzzing coverage.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001760
Changbin Du09a74952019-12-06 17:03:51 -08001761config KCOV_INSTRUMENT_ALL
1762 bool "Instrument all code by default"
1763 depends on KCOV
1764 default y
1765 help
1766 If you are doing generic system call fuzzing (like e.g. syzkaller),
1767 then you will want to instrument the whole kernel and you should
1768 say y here. If you are doing more targeted fuzzing (like e.g.
1769 filesystem fuzzing with AFL) then you will want to enable coverage
1770 for more specific subsets of files, and should say n here.
Brendan Higgins84bc8092019-09-23 02:02:36 -07001771
Vincent Legolld3deafa2018-02-06 15:38:38 -08001772menuconfig RUNTIME_TESTING_MENU
1773 bool "Runtime Testing"
Anders Roxell908009e82018-02-21 14:46:05 -08001774 def_bool y
Vincent Legolld3deafa2018-02-06 15:38:38 -08001775
1776if RUNTIME_TESTING_MENU
Dave Hansen881c5142013-07-01 13:04:44 -07001777
1778config LKDTM
1779 tristate "Linux Kernel Dump Test Tool Module"
1780 depends on DEBUG_FS
Dave Hansen881c5142013-07-01 13:04:44 -07001781 help
1782 This module enables testing of the different dumping mechanisms by
1783 inducing system failures at predefined crash points.
1784 If you don't need it: say N
1785 Choose M here to compile this code as a module. The module will be
1786 called lkdtm.
1787
1788 Documentation on how to use the module can be found in
Mauro Carvalho Chehab10ffebb2019-06-12 14:52:44 -03001789 Documentation/fault-injection/provoke-crashes.rst
Dave Hansen881c5142013-07-01 13:04:44 -07001790
1791config TEST_LIST_SORT
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001792 tristate "Linked list sorting test"
1793 depends on DEBUG_KERNEL || m
Dave Hansen881c5142013-07-01 13:04:44 -07001794 help
1795 Enable this to turn on 'list_sort()' function test. This test is
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001796 executed only once during system boot (so affects only boot time),
1797 or at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001798
1799 If unsure, say N.
1800
Ian Rogers6e246282020-02-13 23:51:29 -08001801config TEST_MIN_HEAP
1802 tristate "Min heap test"
1803 depends on DEBUG_KERNEL || m
1804 help
1805 Enable this to turn on min heap function tests. This test is
1806 executed only once during system boot (so affects only boot time),
1807 or at module load time.
1808
1809 If unsure, say N.
1810
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001811config TEST_SORT
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001812 tristate "Array-based sort test"
1813 depends on DEBUG_KERNEL || m
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001814 help
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001815 This option enables the self-test function of 'sort()' at boot,
1816 or at module load time.
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001817
1818 If unsure, say N.
1819
Dave Hansen881c5142013-07-01 13:04:44 -07001820config KPROBES_SANITY_TEST
1821 bool "Kprobes sanity tests"
1822 depends on DEBUG_KERNEL
1823 depends on KPROBES
Dave Hansen881c5142013-07-01 13:04:44 -07001824 help
1825 This option provides for testing basic kprobes functionality on
Masami Hiramatsu5a6cf772018-06-20 01:05:07 +09001826 boot. Samples of kprobe and kretprobe are inserted and
Dave Hansen881c5142013-07-01 13:04:44 -07001827 verified for functionality.
1828
1829 Say N if you are unsure.
1830
1831config BACKTRACE_SELF_TEST
1832 tristate "Self test for the backtrace code"
1833 depends on DEBUG_KERNEL
Dave Hansen881c5142013-07-01 13:04:44 -07001834 help
1835 This option provides a kernel module that can be used to test
1836 the kernel stack backtrace code. This option is not useful
1837 for distributions or general kernels, but only for kernel
1838 developers working on architecture code.
1839
1840 Note that if you want to also test saved backtraces, you will
1841 have to enable STACKTRACE as well.
1842
1843 Say N if you are unsure.
1844
Michel Lespinasse910a7422012-10-08 16:30:39 -07001845config RBTREE_TEST
1846 tristate "Red-Black tree test"
Cody P Schafer7c993e12013-09-11 14:25:19 -07001847 depends on DEBUG_KERNEL
Michel Lespinasse910a7422012-10-08 16:30:39 -07001848 help
1849 A benchmark measuring the performance of the rbtree library.
1850 Also includes rbtree invariant checks.
1851
Ferdinand Blomqvist4b4f3ac2019-06-20 17:10:33 +03001852config REED_SOLOMON_TEST
1853 tristate "Reed-Solomon library test"
1854 depends on DEBUG_KERNEL || m
1855 select REED_SOLOMON
1856 select REED_SOLOMON_ENC16
1857 select REED_SOLOMON_DEC16
1858 help
1859 This option enables the self-test function of rslib at boot,
1860 or at module load time.
1861
1862 If unsure, say N.
1863
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001864config INTERVAL_TREE_TEST
1865 tristate "Interval tree test"
Davidlohr Bueso0f789b62017-07-10 15:51:43 -07001866 depends on DEBUG_KERNEL
Chris Wilsona88cc102014-03-17 12:21:54 +00001867 select INTERVAL_TREE
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001868 help
1869 A benchmark measuring the performance of the interval tree library
1870
Greg Thelen623fd802013-11-12 15:08:34 -08001871config PERCPU_TEST
1872 tristate "Per cpu operations test"
1873 depends on m && DEBUG_KERNEL
1874 help
1875 Enable this option to build test module which validates per-cpu
1876 operations.
1877
1878 If unsure, say N.
1879
Dave Hansen881c5142013-07-01 13:04:44 -07001880config ATOMIC64_SELFTEST
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001881 tristate "Perform an atomic64_t self-test"
Dave Hansen881c5142013-07-01 13:04:44 -07001882 help
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001883 Enable this option to test the atomic64_t functions at boot or
1884 at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001885
1886 If unsure, say N.
1887
1888config ASYNC_RAID6_TEST
1889 tristate "Self test for hardware accelerated raid6 recovery"
1890 depends on ASYNC_RAID6_RECOV
1891 select ASYNC_MEMCPY
1892 ---help---
1893 This is a one-shot self test that permutes through the
1894 recovery of all the possible two disk failure scenarios for a
1895 N-disk array. Recovery is performed with the asynchronous
1896 raid6 recovery routines, and will optionally use an offload
1897 engine if one is available.
1898
1899 If unsure, say N.
1900
Andy Shevchenko64d1d772015-02-12 15:02:21 -08001901config TEST_HEXDUMP
1902 tristate "Test functions located in the hexdump module at runtime"
1903
Dave Hansen881c5142013-07-01 13:04:44 -07001904config TEST_STRING_HELPERS
1905 tristate "Test functions located in the string_helpers module at runtime"
1906
Tobin C. Harding0b0600c2019-04-05 12:58:59 +11001907config TEST_STRSCPY
1908 tristate "Test strscpy*() family of functions at runtime"
1909
Dave Hansen881c5142013-07-01 13:04:44 -07001910config TEST_KSTRTOX
1911 tristate "Test kstrto*() family of functions at runtime"
1912
Rasmus Villemoes707cc722015-11-06 16:30:29 -08001913config TEST_PRINTF
1914 tristate "Test printf() family of functions at runtime"
1915
David Decotigny5fd003f2016-02-19 09:24:00 -05001916config TEST_BITMAP
1917 tristate "Test bitmap_*() family of functions at runtime"
David Decotigny5fd003f2016-02-19 09:24:00 -05001918 help
1919 Enable this option to test the bitmap functions at boot.
1920
1921 If unsure, say N.
1922
Johannes Berg0e2dc702018-06-20 08:58:30 +02001923config TEST_BITFIELD
1924 tristate "Test bitfield functions at runtime"
1925 help
1926 Enable this option to test the bitfield functions at boot.
1927
1928 If unsure, say N.
1929
Andy Shevchenkocfaff0e2016-05-30 17:40:41 +03001930config TEST_UUID
1931 tristate "Test functions located in the uuid module at runtime"
1932
Matthew Wilcoxad3d6c72017-11-07 14:57:46 -05001933config TEST_XARRAY
1934 tristate "Test the XArray code at runtime"
1935
Rasmus Villemoes455a35a2018-05-08 00:36:28 +02001936config TEST_OVERFLOW
1937 tristate "Test check_*_overflow() functions at runtime"
1938
Thomas Graf7e1e7762014-08-02 11:47:44 +02001939config TEST_RHASHTABLE
Geert Uytterhoeven9d6dbe12015-01-29 15:40:25 +01001940 tristate "Perform selftest on resizable hash table"
Thomas Graf7e1e7762014-08-02 11:47:44 +02001941 help
1942 Enable this option to test the rhashtable functions at boot.
1943
1944 If unsure, say N.
1945
George Spelvin468a9422016-05-26 22:11:51 -04001946config TEST_HASH
1947 tristate "Perform selftest on hash functions"
George Spelvin468a9422016-05-26 22:11:51 -04001948 help
Jason A. Donenfeld2c956a62017-01-08 13:54:00 +01001949 Enable this option to test the kernel's integer (<linux/hash.h>),
1950 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
1951 hash functions on boot (or module load).
George Spelvin468a9422016-05-26 22:11:51 -04001952
1953 This is intended to help people writing architecture-specific
1954 optimized versions. If unsure, say N.
1955
Matthew Wilcox8ab8ba32018-06-18 16:59:29 -04001956config TEST_IDA
1957 tristate "Perform selftest on IDA functions"
1958
Jiri Pirko44091d22017-02-03 10:29:06 +01001959config TEST_PARMAN
1960 tristate "Perform selftest on priority array manager"
Jiri Pirko44091d22017-02-03 10:29:06 +01001961 depends on PARMAN
1962 help
1963 Enable this option to test priority array manager on boot
1964 (or module load).
1965
1966 If unsure, say N.
1967
Daniel Lezcano6aed82d2019-05-27 22:55:19 +02001968config TEST_IRQ_TIMINGS
1969 bool "IRQ timings selftest"
1970 depends on IRQ_TIMINGS
1971 help
1972 Enable this option to test the irq timings code on boot.
1973
1974 If unsure, say N.
1975
Valentin Rothberg8a6f0b42014-10-13 15:51:38 -07001976config TEST_LKM
Kees Cook93e9ef82014-01-23 15:54:37 -08001977 tristate "Test module loading with 'hello world' module"
Kees Cook93e9ef82014-01-23 15:54:37 -08001978 depends on m
1979 help
1980 This builds the "test_module" module that emits "Hello, world"
1981 on printk when loaded. It is designed to be used for basic
1982 evaluation of the module loading subsystem (for example when
1983 validating module verification). It lacks any extra dependencies,
1984 and will not normally be loaded by the system unless explicitly
1985 requested by name.
1986
1987 If unsure, say N.
1988
Uladzislau Rezki (Sony)3f21a6b2019-03-05 15:43:34 -08001989config TEST_VMALLOC
1990 tristate "Test module for stress/performance analysis of vmalloc allocator"
1991 default n
1992 depends on MMU
1993 depends on m
1994 help
1995 This builds the "test_vmalloc" module that should be used for
1996 stress and performance analysis. So, any new change for vmalloc
1997 subsystem can be evaluated from performance and stability point
1998 of view.
1999
2000 If unsure, say N.
2001
Kees Cook3e2a4c12014-01-23 15:54:38 -08002002config TEST_USER_COPY
2003 tristate "Test user/kernel boundary protections"
Kees Cook3e2a4c12014-01-23 15:54:38 -08002004 depends on m
2005 help
2006 This builds the "test_user_copy" module that runs sanity checks
2007 on the copy_to/from_user infrastructure, making sure basic
2008 user/kernel boundary testing is working. If it fails to load,
2009 a regression has been detected in the user/kernel memory boundary
2010 protections.
2011
2012 If unsure, say N.
2013
Alexei Starovoitov64a89462014-05-08 14:10:52 -07002014config TEST_BPF
2015 tristate "Test BPF filter functionality"
Randy Dunlap98920ba2014-05-13 09:58:44 -07002016 depends on m && NET
Alexei Starovoitov64a89462014-05-08 14:10:52 -07002017 help
2018 This builds the "test_bpf" module that runs various test vectors
2019 against the BPF interpreter or BPF JIT compiler depending on the
2020 current setting. This is in particular useful for BPF JIT compiler
2021 development, but also to run regression tests against changes in
Alexei Starovoitov3c731eb2014-09-26 00:17:07 -07002022 the interpreter code. It also enables test stubs for eBPF maps and
2023 verifier used by user space verifier testsuite.
Alexei Starovoitov64a89462014-05-08 14:10:52 -07002024
2025 If unsure, say N.
2026
Mahesh Bandewar509e56b2019-07-01 14:39:01 -07002027config TEST_BLACKHOLE_DEV
2028 tristate "Test blackhole netdev functionality"
2029 depends on m && NET
2030 help
2031 This builds the "test_blackhole_dev" module that validates the
2032 data path through this blackhole netdev.
2033
2034 If unsure, say N.
2035
Yury Norovdceeb3e2018-02-06 15:38:27 -08002036config FIND_BIT_BENCHMARK
Yury Norov4441fca2017-11-17 15:28:31 -08002037 tristate "Test find_bit functions"
Yury Norov4441fca2017-11-17 15:28:31 -08002038 help
2039 This builds the "test_find_bit" module that measure find_*_bit()
2040 functions performance.
2041
2042 If unsure, say N.
2043
Kees Cook0a8adf52014-07-14 14:38:12 -07002044config TEST_FIRMWARE
2045 tristate "Test firmware loading via userspace interface"
Kees Cook0a8adf52014-07-14 14:38:12 -07002046 depends on FW_LOADER
2047 help
2048 This builds the "test_firmware" module that creates a userspace
2049 interface for testing firmware loading. This can be used to
2050 control the triggering of firmware loading without needing an
2051 actual firmware-using device. The contents can be rechecked by
2052 userspace.
2053
2054 If unsure, say N.
2055
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07002056config TEST_SYSCTL
2057 tristate "sysctl test driver"
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07002058 depends on PROC_SYSCTL
2059 help
2060 This builds the "test_sysctl" module. This driver enables to test the
2061 proc sysctl interfaces available to drivers safely without affecting
2062 production knobs which might alter system functionality.
2063
2064 If unsure, say N.
2065
Iurii Zaikin2cb80db2019-09-23 02:02:47 -07002066config SYSCTL_KUNIT_TEST
Alan Maguirec475c772020-01-06 22:28:20 +00002067 tristate "KUnit test for sysctl"
Iurii Zaikin2cb80db2019-09-23 02:02:47 -07002068 depends on KUNIT
2069 help
2070 This builds the proc sysctl unit test, which runs on boot.
2071 Tests the API contract and implementation correctness of sysctl.
2072 For more information on KUnit and unit tests in general please refer
2073 to the KUnit documentation in Documentation/dev-tools/kunit/.
2074
2075 If unsure, say N.
2076
David Gowea2dd7c2019-10-24 15:46:31 -07002077config LIST_KUNIT_TEST
Alan Maguirec475c772020-01-06 22:28:20 +00002078 tristate "KUnit Test for Kernel Linked-list structures"
David Gowea2dd7c2019-10-24 15:46:31 -07002079 depends on KUNIT
2080 help
2081 This builds the linked list KUnit test suite.
2082 It tests that the API and basic functionality of the list_head type
2083 and associated macros.
2084
2085 KUnit tests run during boot and output the results to the debug log
2086 in TAP format (http://testanything.org/). Only useful for kernel devs
2087 running the KUnit test harness, and not intended for inclusion into a
2088 production build.
2089
2090 For more information on KUnit and unit tests in general please refer
2091 to the KUnit documentation in Documentation/dev-tools/kunit/.
2092
2093 If unsure, say N.
2094
David Rileye704f932014-06-16 14:58:32 -07002095config TEST_UDELAY
2096 tristate "udelay test driver"
David Rileye704f932014-06-16 14:58:32 -07002097 help
2098 This builds the "udelay_test" module that helps to make sure
2099 that udelay() is working properly.
2100
2101 If unsure, say N.
2102
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02002103config TEST_STATIC_KEYS
2104 tristate "Test static keys"
Jason Baron579e1ac2015-07-30 03:59:44 +00002105 depends on m
2106 help
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02002107 Test the static key interfaces.
Jason Baron579e1ac2015-07-30 03:59:44 +00002108
2109 If unsure, say N.
2110
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002111config TEST_KMOD
2112 tristate "kmod stress tester"
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002113 depends on m
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002114 depends on NETDEVICES && NET_CORE && INET # for TUN
YueHaibingae3d6a32019-04-25 22:23:44 -07002115 depends on BLOCK
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002116 select TEST_LKM
2117 select XFS_FS
2118 select TUN
2119 select BTRFS_FS
2120 help
2121 Test the kernel's module loading mechanism: kmod. kmod implements
2122 support to load modules using the Linux kernel's usermode helper.
2123 This test provides a series of tests against kmod.
2124
2125 Although technically you can either build test_kmod as a module or
2126 into the kernel we disallow building it into the kernel since
2127 it stress tests request_module() and this will very likely cause
2128 some issues by taking over precious threads available from other
2129 module load requests, ultimately this could be fatal.
2130
2131 To run tests run:
2132
2133 tools/testing/selftests/kmod/kmod.sh --help
2134
2135 If unsure, say N.
2136
Florian Fainellie4dace32017-09-08 16:15:31 -07002137config TEST_DEBUG_VIRTUAL
2138 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2139 depends on DEBUG_VIRTUAL
2140 help
2141 Test the kernel's ability to detect incorrect calls to
2142 virt_to_phys() done against the non-linear part of the
2143 kernel's virtual address map.
2144
2145 If unsure, say N.
2146
Alexander Shishkince76d932018-10-05 15:43:05 +03002147config TEST_MEMCAT_P
2148 tristate "Test memcat_p() helper function"
2149 help
2150 Test the memcat_p() helper for correctly merging two
2151 pointer arrays together.
2152
2153 If unsure, say N.
2154
Joe Lawrencea2818ee2019-01-09 13:43:29 +01002155config TEST_LIVEPATCH
2156 tristate "Test livepatching"
2157 default n
Joe Lawrencebae05432019-01-31 11:41:24 -05002158 depends on DYNAMIC_DEBUG
Joe Lawrencea2818ee2019-01-09 13:43:29 +01002159 depends on LIVEPATCH
2160 depends on m
2161 help
2162 Test kernel livepatching features for correctness. The tests will
2163 load test modules that will be livepatched in various scenarios.
2164
2165 To run all the livepatching tests:
2166
2167 make -C tools/testing/selftests TARGETS=livepatch run_tests
2168
2169 Alternatively, individual tests may be invoked:
2170
2171 tools/testing/selftests/livepatch/test-callbacks.sh
2172 tools/testing/selftests/livepatch/test-livepatch.sh
2173 tools/testing/selftests/livepatch/test-shadow-vars.sh
2174
2175 If unsure, say N.
2176
Jiri Pirko0a020d42018-11-14 08:22:28 +00002177config TEST_OBJAGG
2178 tristate "Perform selftest on object aggreration manager"
2179 default n
2180 depends on OBJAGG
2181 help
2182 Enable this option to test object aggregation manager on boot
2183 (or module load).
2184
Jiri Pirko0a020d42018-11-14 08:22:28 +00002185
Kees Cook50ceaa95e2019-01-23 12:24:32 -07002186config TEST_STACKINIT
2187 tristate "Test level of stack variable initialization"
2188 help
2189 Test if the kernel is zero-initializing stack variables and
2190 padding. Coverage is controlled by compiler flags,
2191 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2192 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2193
2194 If unsure, say N.
2195
Alexander Potapenko5015a302019-07-16 16:27:27 -07002196config TEST_MEMINIT
2197 tristate "Test heap/page initialization"
2198 help
2199 Test if the kernel is zero-initializing heap and page allocations.
2200 This can be useful to test init_on_alloc and init_on_free features.
2201
2202 If unsure, say N.
2203
Vincent Legolld3deafa2018-02-06 15:38:38 -08002204endif # RUNTIME_TESTING_MENU
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002205
2206config MEMTEST
2207 bool "Memtest"
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002208 ---help---
2209 This option adds a kernel parameter 'memtest', which allows memtest
2210 to be set.
2211 memtest=0, mean disabled; -- default
2212 memtest=1, mean do 1 test pattern;
2213 ...
2214 memtest=17, mean do 17 test patterns.
2215 If you are unsure how to answer this question, answer N.
2216
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002217
Christoph Hellwig06ec64b2018-07-31 13:39:31 +02002218
Branden Bonabyaf9ca6f2019-10-03 17:01:49 -04002219config HYPERV_TESTING
2220 bool "Microsoft Hyper-V driver testing"
2221 default n
2222 depends on HYPERV && DEBUG_FS
2223 help
2224 Select this option to enable Hyper-V vmbus testing.
2225
Changbin Du045f6d72019-12-17 20:51:56 -08002226endmenu # "Kernel Testing and Coverage"
2227
Christoph Hellwig06ec64b2018-07-31 13:39:31 +02002228endmenu # Kernel hacking