blob: d7da101bccc81fb0eb7545ecac6a490da3c27e93 [file] [log] [blame]
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
Nick Desaulniers10e68b022020-05-26 10:18:29 -0700216config DEBUG_INFO_COMPRESSED
217 bool "Compressed debugging information"
218 depends on DEBUG_INFO
219 depends on $(cc-option,-gz=zlib)
220 depends on $(as-option,-Wa$(comma)--compress-debug-sections=zlib)
221 depends on $(ld-option,--compress-debug-sections=zlib)
222 help
223 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
224 5.0+, binutils 2.26+, and zlib.
225
226 Users of dpkg-deb via scripts/package/builddeb may find an increase in
227 size of their debug .deb packages with this config set, due to the
228 debug info being compressed with zlib, then the object files being
229 recompressed with a different compression scheme. But this is still
230 preferable to setting $KDEB_COMPRESS to "none" which would be even
231 larger.
232
Andi Kleen866ced92014-07-30 20:50:18 +0200233config DEBUG_INFO_SPLIT
234 bool "Produce split debuginfo in .dwo files"
Arnd Bergmanna687a532018-03-07 23:30:54 +0100235 depends on DEBUG_INFO
Masahiro Yamada9d937442019-02-22 16:56:09 +0900236 depends on $(cc-option,-gsplit-dwarf)
Andi Kleen866ced92014-07-30 20:50:18 +0200237 help
238 Generate debug info into separate .dwo files. This significantly
239 reduces the build directory size for builds with DEBUG_INFO,
240 because it stores the information only once on disk in .dwo
241 files instead of multiple times in object files and executables.
242 In addition the debug information is also compressed.
243
244 Requires recent gcc (4.7+) and recent gdb/binutils.
245 Any tool that packages or reads debug information would need
246 to know about the .dwo files and include them.
247 Incompatible with older versions of ccache.
248
Andi Kleenbfaf2dd2014-07-30 20:50:19 +0200249config DEBUG_INFO_DWARF4
250 bool "Generate dwarf4 debuginfo"
251 depends on DEBUG_INFO
Masahiro Yamada9d937442019-02-22 16:56:09 +0900252 depends on $(cc-option,-gdwarf-4)
Andi Kleenbfaf2dd2014-07-30 20:50:19 +0200253 help
254 Generate dwarf4 debug info. This requires recent versions
255 of gcc and gdb. It makes the debug information larger.
256 But it significantly improves the success of resolving
257 variables in gdb on optimized code.
258
Andrii Nakryikoe83b9f52019-04-02 09:49:50 -0700259config DEBUG_INFO_BTF
260 bool "Generate BTF typeinfo"
261 depends on DEBUG_INFO
Slava Bacherikov7d32e692020-04-02 23:41:39 +0300262 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
263 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
Andrii Nakryikoe83b9f52019-04-02 09:49:50 -0700264 help
265 Generate deduplicated BTF type information from DWARF debug info.
266 Turning this on expects presence of pahole tool, which will convert
267 DWARF type info into equivalent deduplicated BTF type info.
268
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800269config GDB_SCRIPTS
270 bool "Provide GDB scripts for kernel debugging"
271 depends on DEBUG_INFO
272 help
273 This creates the required links to GDB helper scripts in the
274 build directory. If you load vmlinux into gdb, the helper
275 scripts will be automatically imported by gdb as well, and
276 additional functions are available to analyze a Linux kernel
Andreas Platschek700199b02016-12-14 15:05:40 -0800277 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
278 for further details.
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800279
Andrew Mortoncebc04b2006-08-14 22:43:18 -0700280config ENABLE_MUST_CHECK
281 bool "Enable __must_check logic"
282 default y
283 help
284 Enable the __must_check logic in the kernel build. Disable this to
285 suppress the "warning: ignoring return value of 'foo', declared with
286 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287
Andi Kleen35bb5b12008-02-22 15:15:03 +0100288config FRAME_WARN
Masahiro Yamadaa83e4ca2020-02-17 00:19:36 +0900289 int "Warn for stack frames larger than"
Andi Kleen35bb5b12008-02-22 15:15:03 +0100290 range 0 8192
Kees Cook0e07f662016-10-27 17:46:41 -0700291 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
Helge Deller432654d2017-09-11 21:41:43 +0200292 default 1280 if (!64BIT && PARISC)
293 default 1024 if (!64BIT && !PARISC)
Andi Kleen35bb5b12008-02-22 15:15:03 +0100294 default 2048 if 64BIT
295 help
296 Tell gcc to warn at build time for stack frames larger than this.
297 Setting this too low will cause a lot of warnings.
298 Setting it to 0 disables the warning.
Andi Kleen35bb5b12008-02-22 15:15:03 +0100299
Randy Dunlap99657c72009-09-18 12:49:22 -0700300config STRIP_ASM_SYMS
301 bool "Strip assembler-generated symbols during link"
302 default n
303 help
304 Strip internal assembler-generated symbols during a link (symbols
305 that look like '.Lxxx') so they don't pollute the output of
306 get_wchan() and suchlike.
307
Andi Kleen1873e872012-03-28 11:51:18 -0700308config READABLE_ASM
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800309 bool "Generate readable assembler code"
310 depends on DEBUG_KERNEL
Don Mullisbf4735a2006-12-10 02:18:37 -0800311 help
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800312 Disable some compiler optimizations that tend to generate human unreadable
313 assembler output. This may make the kernel slightly slower, but it helps
314 to keep kernel developers who have to stare a lot at assembler listings
315 sane.
Don Mullisbf4735a2006-12-10 02:18:37 -0800316
Masahiro Yamadae949f4c2019-06-04 19:13:59 +0900317config HEADERS_INSTALL
318 bool "Install uapi headers to usr/include"
Don Mullisbf4735a2006-12-10 02:18:37 -0800319 depends on !UML
320 help
Masahiro Yamadae949f4c2019-06-04 19:13:59 +0900321 This option will install uapi headers (headers exported to user-space)
322 into the usr/include directory for use during the kernel build.
323 This is unneeded for building the kernel itself, but needed for some
324 user-space program samples. It is also needed by some features such
325 as uapi header sanity checks.
326
Sam Ravnborg91341d42008-01-21 21:31:44 +0100327config DEBUG_SECTION_MISMATCH
328 bool "Enable full Section mismatch analysis"
Sam Ravnborg91341d42008-01-21 21:31:44 +0100329 help
330 The section mismatch analysis checks if there are illegal
331 references from one section to another section.
Michael Wittene809ab02011-04-17 04:08:48 +0000332 During linktime or runtime, some sections are dropped;
333 any use of code/data previously in these sections would
Sam Ravnborg91341d42008-01-21 21:31:44 +0100334 most likely result in an oops.
Michael Wittene809ab02011-04-17 04:08:48 +0000335 In the code, functions and variables are annotated with
Paul Gortmaker0db06282013-06-19 14:53:51 -0400336 __init,, etc. (see the full list in include/linux/init.h),
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100337 which results in the code/data being placed in specific sections.
Michael Wittene809ab02011-04-17 04:08:48 +0000338 The section mismatch analysis is always performed after a full
339 kernel build, and enabling this option causes the following
Masahiro Yamadab7dca6d2019-07-17 15:17:57 +0900340 additional step to occur:
Michael Wittene809ab02011-04-17 04:08:48 +0000341 - Add the option -fno-inline-functions-called-once to gcc commands.
342 When inlining a function annotated with __init in a non-init
343 function, we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100344 the analysis would not catch the illegal reference.
Michael Wittene809ab02011-04-17 04:08:48 +0000345 This option tells gcc to inline less (but it does result in
346 a larger kernel).
Sam Ravnborg91341d42008-01-21 21:31:44 +0100347
Nicolas Boichat47490ec2015-10-06 09:44:42 +1030348config SECTION_MISMATCH_WARN_ONLY
349 bool "Make section mismatch errors non-fatal"
350 default y
351 help
352 If you say N here, the build process will fail if there are any
353 section mismatch, instead of just throwing warnings.
354
355 If unsure, say Y.
356
Dave Hansen6dfc0662013-07-01 13:04:46 -0700357#
358# Select this config option from the architecture Kconfig, if it
359# is preferred to always offer frame pointers as a config
360# option on the architecture (regardless of KERNEL_DEBUG):
361#
362config ARCH_WANT_FRAME_POINTERS
363 bool
Dave Hansen6dfc0662013-07-01 13:04:46 -0700364
365config FRAME_POINTER
366 bool "Compile the kernel with frame pointers"
Arnd Bergmanna687a532018-03-07 23:30:54 +0100367 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
Dave Hansen6dfc0662013-07-01 13:04:46 -0700368 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
369 help
370 If you say Y here the resulting kernel image will be slightly
371 larger and slower, but it gives very useful debugging information
372 in case of kernel bugs. (precise oopses/stacktraces/warnings)
373
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600374config STACK_VALIDATION
375 bool "Compile-time stack metadata validation"
376 depends on HAVE_STACK_VALIDATION
377 default n
378 help
379 Add compile-time checks to validate stack metadata, including frame
380 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
381 that runtime stack traces are more reliable.
382
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500383 This is also a prerequisite for generation of ORC unwind data, which
Josh Poimboeuf11af8472017-10-13 15:02:00 -0500384 is needed for CONFIG_UNWINDER_ORC.
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500385
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600386 For more information, see
387 tools/objtool/Documentation/stack-validation.txt.
388
Dave Hansen6dfc0662013-07-01 13:04:46 -0700389config DEBUG_FORCE_WEAK_PER_CPU
390 bool "Force weak per-cpu definitions"
391 depends on DEBUG_KERNEL
392 help
393 s390 and alpha require percpu variables in modules to be
394 defined weak to work around addressing range issue which
395 puts the following two restrictions on percpu variable
396 definitions.
397
398 1. percpu symbols must be unique whether static or not
399 2. percpu variables can't be defined inside a function
400
401 To ensure that generic code follows the above rules, this
402 option forces all percpu variables to be defined as weak.
403
404endmenu # "Compiler options"
405
Changbin Du6210b642019-12-06 17:03:42 -0800406menu "Generic Kernel Debugging Instruments"
407
Dave Hansen6dfc0662013-07-01 13:04:46 -0700408config MAGIC_SYSRQ
409 bool "Magic SysRq key"
410 depends on !UML
411 help
412 If you say Y here, you will have some control over the system even
413 if the system crashes for example during kernel debugging (e.g., you
414 will be able to flush the buffer cache to disk, reboot the system
415 immediately or dump some status information). This is accomplished
416 by pressing various keys while holding SysRq (Alt+PrintScreen). It
417 also works on a serial console (on PC hardware at least), if you
418 send a BREAK and then within 5 seconds a command keypress. The
Hans Holmbergf8998c22017-03-16 09:37:32 +0100419 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
420 Don't say Y unless you really know what this hack does.
Dave Hansen6dfc0662013-07-01 13:04:46 -0700421
Ben Hutchings8eaede42013-10-07 01:05:46 +0100422config MAGIC_SYSRQ_DEFAULT_ENABLE
423 hex "Enable magic SysRq key functions by default"
424 depends on MAGIC_SYSRQ
425 default 0x1
426 help
427 Specifies which SysRq key functions are enabled by default.
428 This may be set to 1 or 0 to enable or disable them all, or
Hans Holmbergf8998c22017-03-16 09:37:32 +0100429 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
Ben Hutchings8eaede42013-10-07 01:05:46 +0100430
Felix Fietkau732dbf32016-12-22 08:31:34 +0100431config MAGIC_SYSRQ_SERIAL
432 bool "Enable magic SysRq key over serial"
433 depends on MAGIC_SYSRQ
434 default y
435 help
436 Many embedded boards have a disconnected TTL level serial which can
437 generate some garbage that can lead to spurious false sysrq detects.
438 This option allows you to decide whether you want to enable the
439 magic SysRq key.
440
Dmitry Safonov68af4312020-03-02 17:51:35 +0000441config MAGIC_SYSRQ_SERIAL_SEQUENCE
442 string "Char sequence that enables magic SysRq over serial"
443 depends on MAGIC_SYSRQ_SERIAL
444 default ""
445 help
446 Specifies a sequence of characters that can follow BREAK to enable
447 SysRq on a serial console.
448
Dmitry Safonovd3394b32020-03-06 15:31:56 +0000449 If unsure, leave an empty string and the option will not be enabled.
450
Changbin Duec29a5c2019-12-06 17:04:06 -0800451config DEBUG_FS
452 bool "Debug Filesystem"
453 help
454 debugfs is a virtual file system that kernel developers use to put
455 debugging files into. Enable this option to be able to read and
456 write to these files.
457
458 For detailed documentation on the debugfs API, see
459 Documentation/filesystems/.
460
461 If unsure, say N.
462
Changbin Du6210b642019-12-06 17:03:42 -0800463source "lib/Kconfig.kgdb"
464
465source "lib/Kconfig.ubsan"
466
467endmenu
468
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800469config DEBUG_KERNEL
470 bool "Kernel debugging"
471 help
472 Say Y here if you are developing drivers or trying to debug and
473 identify kernel problems.
474
Sinan Kayac66d7a22019-05-14 15:44:00 -0700475config DEBUG_MISC
476 bool "Miscellaneous debug code"
477 default DEBUG_KERNEL
478 depends on DEBUG_KERNEL
479 help
480 Say Y here if you need to enable miscellaneous debug code that should
481 be under a more specific debug option but isn't.
482
483
Dave Hansen0610c8a2013-07-01 13:04:43 -0700484menu "Memory Debugging"
David Woodhousea304e1b2007-02-12 00:52:00 -0800485
Masahiro Yamada8636a1f2018-12-11 20:01:04 +0900486source "mm/Kconfig.debug"
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800487
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700488config DEBUG_OBJECTS
489 bool "Debug object operations"
490 depends on DEBUG_KERNEL
491 help
492 If you say Y here, additional code will be inserted into the
493 kernel to track the life time of various objects and validate
494 the operations on those objects.
495
496config DEBUG_OBJECTS_SELFTEST
497 bool "Debug objects selftest"
498 depends on DEBUG_OBJECTS
499 help
500 This enables the selftest of the object debug code.
501
502config DEBUG_OBJECTS_FREE
503 bool "Debug objects in freed memory"
504 depends on DEBUG_OBJECTS
505 help
506 This enables checks whether a k/v free operation frees an area
507 which contains an object which has not been deactivated
508 properly. This can make kmalloc/kfree-intensive workloads
509 much slower.
510
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700511config DEBUG_OBJECTS_TIMERS
512 bool "Debug timer objects"
513 depends on DEBUG_OBJECTS
514 help
515 If you say Y here, additional code will be inserted into the
516 timer routines to track the life time of timer objects and
517 validate the timer operations.
518
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900519config DEBUG_OBJECTS_WORK
520 bool "Debug work objects"
521 depends on DEBUG_OBJECTS
522 help
523 If you say Y here, additional code will be inserted into the
524 work queue routines to track the life time of work objects and
525 validate the work operations.
526
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400527config DEBUG_OBJECTS_RCU_HEAD
528 bool "Debug RCU callbacks objects"
Mathieu Desnoyersfc2ecf72011-02-23 09:42:14 -0800529 depends on DEBUG_OBJECTS
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400530 help
531 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
532
Tejun Heoe2852ae2010-10-26 14:23:05 -0700533config DEBUG_OBJECTS_PERCPU_COUNTER
534 bool "Debug percpu counter objects"
535 depends on DEBUG_OBJECTS
536 help
537 If you say Y here, additional code will be inserted into the
538 percpu counter routines to track the life time of percpu counter
539 objects and validate the percpu counter operations.
540
Ingo Molnar3ae70202008-11-26 10:02:00 +0100541config DEBUG_OBJECTS_ENABLE_DEFAULT
542 int "debug_objects bootup default value (0-1)"
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800543 range 0 1
544 default "1"
545 depends on DEBUG_OBJECTS
546 help
547 Debug objects boot parameter default value
Ingo Molnar3ae70202008-11-26 10:02:00 +0100548
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800550 bool "Debug slab memory allocations"
Levin, Alexander (Sasha Levin)4675ff02017-11-15 17:36:02 -0800551 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 help
553 Say Y here to have the kernel do limited verification on memory
554 allocation as well as poisoning memory on free to catch use of freed
555 memory. This can make kmalloc/kfree-intensive workloads much slower.
556
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700557config SLUB_DEBUG_ON
558 bool "SLUB debugging on by default"
Levin, Alexander (Sasha Levin)4675ff02017-11-15 17:36:02 -0800559 depends on SLUB && SLUB_DEBUG
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700560 default n
561 help
562 Boot with debugging on by default. SLUB boots by default with
563 the runtime debug capabilities switched off. Enabling this is
564 equivalent to specifying the "slub_debug" parameter on boot.
565 There is no support for more fine grained debug control like
566 possible with slub_debug=xxx. SLUB debugging may be switched
567 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
568 "slub_debug=-".
569
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800570config SLUB_STATS
571 default n
572 bool "Enable SLUB performance statistics"
Christoph Lameterab4d5ed2010-10-05 13:57:26 -0500573 depends on SLUB && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800574 help
575 SLUB statistics are useful to debug SLUBs allocation behavior in
576 order find ways to optimize the allocator. This should never be
577 enabled for production use since keeping statistics slows down
578 the allocator by a few percentage points. The slabinfo command
579 supports the determination of the most active slabs to figure
580 out which slabs are relevant to a particular load.
581 Try running: slabinfo -DA
582
Catalin Marinasb69ec422012-10-08 16:28:11 -0700583config HAVE_DEBUG_KMEMLEAK
584 bool
585
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100586config DEBUG_KMEMLEAK
587 bool "Kernel memory leak detector"
Kees Cook525c1f92013-01-16 18:54:16 -0800588 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
Catalin Marinas79e0d9b2011-04-27 17:06:19 +0100589 select DEBUG_FS
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100590 select STACKTRACE if STACKTRACE_SUPPORT
591 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800592 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100593 help
594 Say Y here if you want to enable the memory leak
595 detector. The memory allocation/freeing is traced in a way
596 similar to the Boehm's conservative garbage collector, the
597 difference being that the orphan objects are not freed but
598 only shown in /sys/kernel/debug/kmemleak. Enabling this
599 feature will introduce an overhead to memory
Andreas Platschek700199b02016-12-14 15:05:40 -0800600 allocations. See Documentation/dev-tools/kmemleak.rst for more
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100601 details.
602
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100603 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
604 of finding leaks due to the slab objects poisoning.
605
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100606 In order to access the kmemleak file, debugfs needs to be
607 mounted (usually at /sys/kernel/debug).
608
Catalin Marinasc5665862019-09-23 15:34:05 -0700609config DEBUG_KMEMLEAK_MEM_POOL_SIZE
610 int "Kmemleak memory pool size"
Catalin Marinasa9d90582009-06-25 10:16:11 +0100611 depends on DEBUG_KMEMLEAK
Qian Caic59180a2019-09-23 15:34:10 -0700612 range 200 1000000
Nicolas Boichatb751c522019-09-23 15:33:55 -0700613 default 16000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100614 help
615 Kmemleak must track all the memory allocations to avoid
616 reporting false positives. Since memory may be allocated or
Catalin Marinasc5665862019-09-23 15:34:05 -0700617 freed before kmemleak is fully initialised, use a static pool
618 of metadata objects to track such callbacks. After kmemleak is
619 fully initialised, this memory pool acts as an emergency one
620 if slab allocations fail.
Catalin Marinasa9d90582009-06-25 10:16:11 +0100621
Catalin Marinas0822ee42009-06-11 13:24:14 +0100622config DEBUG_KMEMLEAK_TEST
623 tristate "Simple test for the kernel memory leak detector"
Daniel Baluta97182692011-04-04 15:06:44 -0700624 depends on DEBUG_KMEMLEAK && m
Catalin Marinas0822ee42009-06-11 13:24:14 +0100625 help
Daniel Baluta97182692011-04-04 15:06:44 -0700626 This option enables a module that explicitly leaks memory.
Catalin Marinas0822ee42009-06-11 13:24:14 +0100627
628 If unsure, say N.
629
Jason Baronab0155a2010-07-19 11:54:17 +0100630config DEBUG_KMEMLEAK_DEFAULT_OFF
631 bool "Default kmemleak to off"
632 depends on DEBUG_KMEMLEAK
633 help
634 Say Y here to disable kmemleak by default. It can then be enabled
635 on the command line via kmemleak=on.
636
Sri Krishna chowdaryd53ce042018-12-28 00:38:54 -0800637config DEBUG_KMEMLEAK_AUTO_SCAN
638 bool "Enable kmemleak auto scan thread on boot up"
639 default y
640 depends on DEBUG_KMEMLEAK
641 help
642 Depending on the cpu, kmemleak scan may be cpu intensive and can
643 stall user tasks at times. This option enables/disables automatic
644 kmemleak scan at boot up.
645
646 Say N here to disable kmemleak auto scan thread to stop automatic
647 scanning. Disabling this option disables automatic reporting of
648 memory leaks.
649
650 If unsure, say Y.
651
Dave Hansen0610c8a2013-07-01 13:04:43 -0700652config DEBUG_STACK_USAGE
653 bool "Stack utilization instrumentation"
Helge Deller6c31da32016-03-19 17:54:10 +0100654 depends on DEBUG_KERNEL && !IA64
Dave Hansen0610c8a2013-07-01 13:04:43 -0700655 help
656 Enables the display of the minimum amount of free stack which each
657 task has ever had available in the sysrq-T and sysrq-P debug output.
658
659 This option will slow down process creation somewhat.
660
Changbin Dudc9b9632019-12-06 17:03:57 -0800661config SCHED_STACK_END_CHECK
662 bool "Detect stack corruption on calls to schedule()"
663 depends on DEBUG_KERNEL
664 default n
665 help
666 This option checks for a stack overrun on calls to schedule().
667 If the stack end location is found to be over written always panic as
668 the content of the corrupted region can no longer be trusted.
669 This is to ensure no erroneous behaviour occurs which could result in
670 data corruption or a sporadic crash at a later stage once the region
671 is examined. The runtime overhead introduced is minimal.
672
Dave Hansen0610c8a2013-07-01 13:04:43 -0700673config DEBUG_VM
674 bool "Debug VM"
675 depends on DEBUG_KERNEL
676 help
677 Enable this to turn on extended checks in the virtual-memory system
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -0800678 that may impact performance.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700679
680 If unsure, say N.
681
Davidlohr Bueso4f115142014-06-04 16:06:46 -0700682config DEBUG_VM_VMACACHE
683 bool "Debug VMA caching"
684 depends on DEBUG_VM
685 help
686 Enable this to turn on VMA caching debug information. Doing so
687 can cause significant overhead, so only enable it in non-production
688 environments.
689
690 If unsure, say N.
691
Dave Hansen0610c8a2013-07-01 13:04:43 -0700692config DEBUG_VM_RB
693 bool "Debug VM red-black trees"
694 depends on DEBUG_VM
695 help
Davidlohr Buesoa663dad2014-04-18 15:07:22 -0700696 Enable VM red-black tree debugging information and extra validations.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700697
698 If unsure, say N.
699
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800700config DEBUG_VM_PGFLAGS
701 bool "Debug page-flags operations"
702 depends on DEBUG_VM
703 help
704 Enables extra validation on page flags operations.
705
706 If unsure, say N.
707
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800708config ARCH_HAS_DEBUG_VIRTUAL
709 bool
710
Dave Hansen0610c8a2013-07-01 13:04:43 -0700711config DEBUG_VIRTUAL
712 bool "Debug VM translations"
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800713 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
Dave Hansen0610c8a2013-07-01 13:04:43 -0700714 help
715 Enable some costly sanity checks in virtual to page code. This can
716 catch mistakes with virt_to_page() and friends.
717
718 If unsure, say N.
719
720config DEBUG_NOMMU_REGIONS
721 bool "Debug the global anon/private NOMMU mapping region tree"
722 depends on DEBUG_KERNEL && !MMU
723 help
724 This option causes the global tree of anonymous and private mapping
725 regions to be regularly checked for invalid topology.
726
727config DEBUG_MEMORY_INIT
728 bool "Debug memory initialisation" if EXPERT
729 default !EXPERT
730 help
731 Enable this for additional checks during memory initialisation.
732 The sanity checks verify aspects of the VM such as the memory model
733 and other information provided by the architecture. Verbose
734 information will be printed at KERN_DEBUG loglevel depending
735 on the mminit_loglevel= command-line option.
736
737 If unsure, say Y
738
739config MEMORY_NOTIFIER_ERROR_INJECT
740 tristate "Memory hotplug notifier error injection module"
741 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
742 help
743 This option provides the ability to inject artificial errors to
744 memory hotplug notifier chain callbacks. It is controlled through
745 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
746
747 If the notifier call chain should be failed with some events
748 notified, write the error code to "actions/<notifier event>/error".
749
750 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
751
752 # cd /sys/kernel/debug/notifier-error-inject/memory
753 # echo -12 > actions/MEM_GOING_OFFLINE/error
754 # echo offline > /sys/devices/system/memory/memoryXXX/state
755 bash: echo: write error: Cannot allocate memory
756
757 To compile this code as a module, choose M here: the module will
758 be called memory-notifier-error-inject.
759
760 If unsure, say N.
761
762config DEBUG_PER_CPU_MAPS
763 bool "Debug access to per_cpu maps"
764 depends on DEBUG_KERNEL
765 depends on SMP
766 help
767 Say Y to verify that the per_cpu map being accessed has
768 been set up. This adds a fair amount of code to kernel memory
769 and decreases performance.
770
771 Say N if unsure.
772
773config DEBUG_HIGHMEM
774 bool "Highmem debugging"
775 depends on DEBUG_KERNEL && HIGHMEM
776 help
Geert Uytterhoevenb1357c92014-04-14 18:55:50 +0200777 This option enables additional error checking for high memory
778 systems. Disable for production systems.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700779
780config HAVE_DEBUG_STACKOVERFLOW
781 bool
782
783config DEBUG_STACKOVERFLOW
784 bool "Check for stack overflows"
785 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
786 ---help---
787 Say Y here if you want to check for overflows of kernel, IRQ
Borislav Petkovedb0ec02015-01-25 19:50:34 +0100788 and exception stacks (if your architecture uses them). This
Dave Hansen0610c8a2013-07-01 13:04:43 -0700789 option will show detailed messages if free stack space drops
790 below a certain limit.
791
792 These kinds of bugs usually occur when call-chains in the
793 kernel get too deep, especially when interrupts are
794 involved.
795
796 Use this in cases where you see apparently random memory
797 corruption, especially if it appears in 'struct thread_info'
798
799 If in doubt, say "N".
800
Andrey Ryabinin0b24bec2015-02-13 14:39:17 -0800801source "lib/Kconfig.kasan"
802
Dave Hansen0610c8a2013-07-01 13:04:43 -0700803endmenu # "Memory Debugging"
804
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805config DEBUG_SHIRQ
806 bool "Debug shared IRQ handlers"
Martin Schwidefsky0244ad02013-08-30 09:39:53 +0200807 depends on DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 help
809 Enable this to generate a spurious interrupt as soon as a shared
810 interrupt handler is registered, and just before one is deregistered.
811 Drivers ought to be able to handle interrupts coming in at those
812 points; some don't and need to be caught.
813
Changbin Duf43a2892019-12-06 17:03:54 -0800814menu "Debug Oops, Lockups and Hangs"
815
816config PANIC_ON_OOPS
817 bool "Panic on Oops"
818 help
819 Say Y here to enable the kernel to panic when it oopses. This
820 has the same effect as setting oops=panic on the kernel command
821 line.
822
823 This feature is useful to ensure that the kernel does not do
824 anything erroneous after an oops which could result in data
825 corruption or other issues.
826
827 Say N if unsure.
828
829config PANIC_ON_OOPS_VALUE
830 int
831 range 0 1
832 default 0 if !PANIC_ON_OOPS
833 default 1 if PANIC_ON_OOPS
834
835config PANIC_TIMEOUT
836 int "panic timeout"
837 default 0
838 help
839 Set the timeout value (in seconds) until a reboot occurs when the
840 the kernel panics. If n = 0, then we wait forever. A timeout
841 value n > 0 will wait n seconds before rebooting, while a timeout
842 value n < 0 will reboot immediately.
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700843
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844config LOCKUP_DETECTOR
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700845 bool
846
847config SOFTLOCKUP_DETECTOR
848 bool "Detect Soft Lockups"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849 depends on DEBUG_KERNEL && !S390
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700850 select LOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851 help
852 Say Y here to enable the kernel to act as a watchdog to detect
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700853 soft lockups.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854
855 Softlockups are bugs that cause the kernel to loop in kernel
856 mode for more than 20 seconds, without giving other tasks a
857 chance to run. The current stack trace is displayed upon
858 detection and the system will stay locked up.
859
Randy Dunlap5f00ae02018-04-10 16:32:51 -0700860config BOOTPARAM_SOFTLOCKUP_PANIC
861 bool "Panic (Reboot) On Soft Lockups"
862 depends on SOFTLOCKUP_DETECTOR
863 help
864 Say Y here to enable the kernel to panic on "soft lockups",
865 which are bugs that cause the kernel to loop in kernel
866 mode for more than 20 seconds (configurable using the watchdog_thresh
867 sysctl), without giving other tasks a chance to run.
868
869 The panic can be used in combination with panic_timeout,
870 to cause the system to reboot automatically after a
871 lockup has been detected. This feature is useful for
872 high-availability systems that have uptime guarantees and
873 where a lockup must be resolved ASAP.
874
875 Say N if unsure.
876
877config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
878 int
879 depends on SOFTLOCKUP_DETECTOR
880 range 0 1
881 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
882 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
883
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700884config HARDLOCKUP_DETECTOR_PERF
885 bool
886 select SOFTLOCKUP_DETECTOR
887
888#
Thomas Gleixner7edaeb62017-08-15 09:50:13 +0200889# Enables a timestamp based low pass filter to compensate for perf based
890# hard lockup detection which runs too fast due to turbo modes.
891#
892config HARDLOCKUP_CHECK_TIMESTAMP
893 bool
894
895#
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700896# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
897# lockup detector rather than the perf based detector.
898#
899config HARDLOCKUP_DETECTOR
900 bool "Detect Hard Lockups"
901 depends on DEBUG_KERNEL && !S390
902 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
903 select LOCKUP_DETECTOR
904 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
905 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
906 help
907 Say Y here to enable the kernel to act as a watchdog to detect
908 hard lockups.
909
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 Hardlockups are bugs that cause the CPU to loop in kernel mode
911 for more than 10 seconds, without letting other interrupts have a
912 chance to run. The current stack trace is displayed upon detection
913 and the system will stay locked up.
914
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915config BOOTPARAM_HARDLOCKUP_PANIC
916 bool "Panic (Reboot) On Hard Lockups"
917 depends on HARDLOCKUP_DETECTOR
918 help
919 Say Y here to enable the kernel to panic on "hard lockups",
920 which are bugs that cause the kernel to loop in kernel
921 mode with interrupts disabled for more than 10 seconds (configurable
922 using the watchdog_thresh sysctl).
923
924 Say N if unsure.
925
926config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
927 int
928 depends on HARDLOCKUP_DETECTOR
929 range 0 1
930 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
931 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
932
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933config DETECT_HUNG_TASK
934 bool "Detect Hung Tasks"
935 depends on DEBUG_KERNEL
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700936 default SOFTLOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937 help
938 Say Y here to enable the kernel to detect "hung tasks",
939 which are bugs that cause the task to be stuck in
Vivien Didelot96b03ab2016-09-22 16:55:13 -0400940 uninterruptible "D" state indefinitely.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941
942 When a hung task is detected, the kernel will print the
943 current stack trace (which you should report), but the
944 task will stay in uninterruptible state. If lockdep is
945 enabled then all held locks will also be reported. This
946 feature has negligible overhead.
Al Viro871751e2006-03-25 03:06:39 -0800947
948config DEFAULT_HUNG_TASK_TIMEOUT
949 int "Default timeout for hung task detection (in seconds)"
950 depends on DETECT_HUNG_TASK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 default 120
952 help
Ingo Molnar8637c092006-07-03 00:24:38 -0700953 This option controls the default timeout (in seconds) used
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 to determine when a task has become non-responsive and should
955 be considered hung.
956
957 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
958 sysctl or by writing a value to
959 /proc/sys/kernel/hung_task_timeout_secs.
960
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700961 A timeout of 0 disables the check. The default is two minutes.
962 Keeping the default should be fine in most cases.
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700963
964config BOOTPARAM_HUNG_TASK_PANIC
965 bool "Panic (Reboot) On Hung Tasks"
966 depends on DETECT_HUNG_TASK
967 help
968 Say Y here to enable the kernel to panic on "hung tasks",
969 which are bugs that cause the kernel to leave a task stuck
970 in uninterruptible "D" state.
971
972 The panic can be used in combination with panic_timeout,
Thomas Gleixner61a87122006-06-27 02:54:56 -0700973 to cause the system to reboot automatically after a
974 hung task has been detected. This feature is useful for
Roman Zippela1583d32006-06-27 02:55:00 -0700975 high-availability systems that have uptime guarantees and
Thomas Gleixner61a87122006-06-27 02:54:56 -0700976 where a hung tasks must be resolved ASAP.
977
978 Say N if unsure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100980config BOOTPARAM_HUNG_TASK_PANIC_VALUE
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981 int
982 depends on DETECT_HUNG_TASK
983 range 0 1
984 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
985 default 1 if BOOTPARAM_HUNG_TASK_PANIC
986
Tejun Heo82607adc2015-12-08 11:28:04 -0500987config WQ_WATCHDOG
988 bool "Detect Workqueue Stalls"
989 depends on DEBUG_KERNEL
990 help
991 Say Y here to enable stall detection on workqueues. If a
992 worker pool doesn't make forward progress on a pending work
993 item for over a given amount of time, 30s by default, a
994 warning message is printed along with dump of workqueue
995 state. This can be configured through kernel parameter
996 "workqueue.watchdog_thresh" and its sysfs counterpart.
997
Konstantin Khlebnikov30428ef2020-04-06 20:09:47 -0700998config TEST_LOCKUP
999 tristate "Test module to generate lockups"
1000 help
1001 This builds the "test_lockup" module that helps to make sure
1002 that watchdogs and lockup detectors are working properly.
1003
1004 Depending on module parameters it could emulate soft or hard
1005 lockup, "hung task", or locking arbitrary lock for a long time.
1006 Also it could generate series of lockups with cooling-down periods.
1007
1008 If unsure, say N.
1009
Dave Hansen92aef8fb2013-07-01 13:04:50 -07001010endmenu # "Debug lockups and hangs"
1011
Changbin Duebebdd02019-12-06 17:04:00 -08001012menu "Scheduler Debugging"
Jason Baron5800dc32013-11-25 23:23:04 +00001013
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014config SCHED_DEBUG
1015 bool "Collect scheduler debugging info"
1016 depends on DEBUG_KERNEL && PROC_FS
1017 default y
1018 help
1019 If you say Y here, the /proc/sched_debug file will be provided
1020 that can help debug the scheduler. The runtime overhead of this
1021 option is minimal.
1022
Naveen N. Raof6db8342015-06-25 23:53:37 +05301023config SCHED_INFO
1024 bool
1025 default n
1026
Linus Torvalds1da177e2005-04-16 15:20:36 -07001027config SCHEDSTATS
1028 bool "Collect scheduler statistics"
1029 depends on DEBUG_KERNEL && PROC_FS
Naveen N. Raof6db8342015-06-25 23:53:37 +05301030 select SCHED_INFO
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031 help
1032 If you say Y here, additional code will be inserted into the
1033 scheduler and related routines to collect statistics about
1034 scheduler behavior and provide them in /proc/schedstat. These
1035 stats may be useful for both tuning and debugging the scheduler
1036 If you aren't debugging the scheduler or trying to tune a specific
1037 application, you can say N to avoid the very slight overhead
1038 this adds.
1039
Changbin Duebebdd02019-12-06 17:04:00 -08001040endmenu
Aaron Tomlin0d9e2632014-09-12 14:16:19 +01001041
John Stultz3c17ad12015-03-11 21:16:32 -07001042config DEBUG_TIMEKEEPING
1043 bool "Enable extra timekeeping sanity checking"
1044 help
1045 This option will enable additional timekeeping sanity checks
1046 which may be helpful when diagnosing issues where timekeeping
1047 problems are suspected.
1048
1049 This may include checks in the timekeeping hotpaths, so this
1050 option may have a (very small) performance impact to some
1051 workloads.
1052
1053 If unsure, say N.
1054
Linus Torvalds1da177e2005-04-16 15:20:36 -07001055config DEBUG_PREEMPT
1056 bool "Debug preemptible kernel"
Sebastian Andrzej Siewior9f472862019-10-15 21:18:19 +02001057 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001058 default y
1059 help
1060 If you say Y here then the kernel will use a debug variant of the
1061 commonly used smp_processor_id() function and will print warnings
1062 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1063 will detect preemption count underflows.
1064
Dave Hansen9eade162013-07-01 13:04:47 -07001065menu "Lock Debugging (spinlocks, mutexes, etc...)"
1066
Waiman Longf07cbeb2018-03-30 17:27:59 -04001067config LOCK_DEBUGGING_SUPPORT
1068 bool
1069 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1070 default y
1071
Waiman Long19193bc2018-03-30 17:28:00 -04001072config PROVE_LOCKING
1073 bool "Lock debugging: prove locking correctness"
1074 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1075 select LOCKDEP
1076 select DEBUG_SPINLOCK
1077 select DEBUG_MUTEXES
1078 select DEBUG_RT_MUTEXES if RT_MUTEXES
Waiman Longc71fd892019-05-20 16:59:00 -04001079 select DEBUG_RWSEMS
Waiman Long19193bc2018-03-30 17:28:00 -04001080 select DEBUG_WW_MUTEX_SLOWPATH
1081 select DEBUG_LOCK_ALLOC
1082 select TRACE_IRQFLAGS
1083 default n
1084 help
1085 This feature enables the kernel to prove that all locking
1086 that occurs in the kernel runtime is mathematically
1087 correct: that under no circumstance could an arbitrary (and
1088 not yet triggered) combination of observed locking
1089 sequences (on an arbitrary number of CPUs, running an
1090 arbitrary number of tasks and interrupt contexts) cause a
1091 deadlock.
1092
1093 In short, this feature enables the kernel to report locking
1094 related deadlocks before they actually occur.
1095
1096 The proof does not depend on how hard and complex a
1097 deadlock scenario would be to trigger: how many
1098 participant CPUs, tasks and irq-contexts would be needed
1099 for it to trigger. The proof also does not depend on
1100 timing: if a race and a resulting deadlock is possible
1101 theoretically (no matter how unlikely the race scenario
1102 is), it will be proven so and will immediately be
1103 reported by the kernel (once the event is observed that
1104 makes the deadlock theoretically possible).
1105
1106 If a deadlock is impossible (i.e. the locking rules, as
1107 observed by the kernel, are mathematically correct), the
1108 kernel reports nothing.
1109
1110 NOTE: this feature can also be enabled for rwlocks, mutexes
1111 and rwsems - in which case all dependencies between these
1112 different locking variants are observed and mapped too, and
1113 the proof of observed correctness is also maintained for an
1114 arbitrary combination of these separate locking variants.
1115
Mauro Carvalho Chehab387b1462019-04-10 08:32:41 -03001116 For more details, see Documentation/locking/lockdep-design.rst.
Waiman Long19193bc2018-03-30 17:28:00 -04001117
Peter Zijlstrade8f5e42020-03-21 12:26:01 +01001118config PROVE_RAW_LOCK_NESTING
1119 bool "Enable raw_spinlock - spinlock nesting checks"
1120 depends on PROVE_LOCKING
1121 default n
1122 help
1123 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1124 that the lock nesting rules for PREEMPT_RT enabled kernels are
1125 not violated.
1126
1127 NOTE: There are known nesting problems. So if you enable this
1128 option expect lockdep splats until these problems have been fully
1129 addressed which is work in progress. This config switch allows to
1130 identify and analyze these problems. It will be removed and the
1131 check permanentely enabled once the main issues have been fixed.
1132
1133 If unsure, select N.
1134
Waiman Long19193bc2018-03-30 17:28:00 -04001135config LOCK_STAT
1136 bool "Lock usage statistics"
1137 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1138 select LOCKDEP
1139 select DEBUG_SPINLOCK
1140 select DEBUG_MUTEXES
1141 select DEBUG_RT_MUTEXES if RT_MUTEXES
1142 select DEBUG_LOCK_ALLOC
1143 default n
1144 help
1145 This feature enables tracking lock contention points
1146
Mauro Carvalho Chehab387b1462019-04-10 08:32:41 -03001147 For more details, see Documentation/locking/lockstat.rst
Waiman Long19193bc2018-03-30 17:28:00 -04001148
1149 This also enables lock events required by "perf lock",
1150 subcommand of perf.
1151 If you want to use "perf lock", you also need to turn on
1152 CONFIG_EVENT_TRACING.
1153
1154 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1155 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1156
Linus Torvalds1da177e2005-04-16 15:20:36 -07001157config DEBUG_RT_MUTEXES
1158 bool "RT Mutex debugging, deadlock detection"
1159 depends on DEBUG_KERNEL && RT_MUTEXES
1160 help
1161 This allows rt mutex semantics violations and rt mutex related
1162 deadlocks (lockups) to be detected and reported automatically.
1163
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001165 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +05301167 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168 help
1169 Say Y here and build SMP to catch missing spinlock initialization
1170 and certain other kinds of spinlock errors commonly made. This is
1171 best used in conjunction with the NMI watchdog so that spinlock
1172 deadlocks are also debuggable.
1173
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001174config DEBUG_MUTEXES
1175 bool "Mutex debugging: basic checks"
1176 depends on DEBUG_KERNEL
1177 help
1178 This feature allows mutex semantics violations to be detected and
1179 reported.
1180
Daniel Vetter23010022013-06-20 13:31:17 +02001181config DEBUG_WW_MUTEX_SLOWPATH
1182 bool "Wait/wound mutex debugging: Slowpath testing"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001183 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Daniel Vetter23010022013-06-20 13:31:17 +02001184 select DEBUG_LOCK_ALLOC
1185 select DEBUG_SPINLOCK
1186 select DEBUG_MUTEXES
1187 help
1188 This feature enables slowpath testing for w/w mutex users by
1189 injecting additional -EDEADLK wound/backoff cases. Together with
1190 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1191 will test all possible w/w mutex interface abuse with the
1192 exception of simply not acquiring all the required locks.
Rob Clark4d692372014-08-27 11:19:26 -04001193 Note that this feature can introduce significant overhead, so
1194 it really should not be enabled in a production or distro kernel,
1195 even a debug kernel. If you are a driver writer, enable it. If
1196 you are a distro, do not.
Daniel Vetter23010022013-06-20 13:31:17 +02001197
Waiman Long5149cba2018-03-30 17:27:58 -04001198config DEBUG_RWSEMS
1199 bool "RW Semaphore debugging: basic checks"
Waiman Longc71fd892019-05-20 16:59:00 -04001200 depends on DEBUG_KERNEL
Waiman Long5149cba2018-03-30 17:27:58 -04001201 help
Waiman Longc71fd892019-05-20 16:59:00 -04001202 This debugging feature allows mismatched rw semaphore locks
1203 and unlocks to be detected and reported.
Waiman Long5149cba2018-03-30 17:27:58 -04001204
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001205config DEBUG_LOCK_ALLOC
1206 bool "Lock debugging: detect incorrect freeing of live locks"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001207 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001208 select DEBUG_SPINLOCK
1209 select DEBUG_MUTEXES
Peter Zijlstraf5694782016-09-19 12:15:37 +02001210 select DEBUG_RT_MUTEXES if RT_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001211 select LOCKDEP
1212 help
1213 This feature will check whether any held lock (spinlock, rwlock,
1214 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1215 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1216 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1217 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1218 held during task exit.
1219
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001220config LOCKDEP
1221 bool
Waiman Longf07cbeb2018-03-30 17:27:59 -04001222 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001223 select STACKTRACE
Stefan Agnerf9b58e82018-09-30 23:02:33 +01001224 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001225 select KALLSYMS
1226 select KALLSYMS_ALL
1227
Daniel Jordan395102d2017-04-10 11:50:52 -04001228config LOCKDEP_SMALL
1229 bool
1230
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001231config DEBUG_LOCKDEP
1232 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -07001233 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001234 help
1235 If you say Y here, the lock dependency engine will do
1236 additional runtime checks to debug itself, at the price
1237 of more runtime overhead.
1238
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001239config DEBUG_ATOMIC_SLEEP
1240 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +02001241 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001242 depends on DEBUG_KERNEL
Christoph Hellwig87a4c372018-07-31 13:39:32 +02001243 depends on !ARCH_NO_PREEMPT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001244 help
1245 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001246 noisy if they are called inside atomic sections: when a spinlock is
1247 held, inside an rcu read side critical section, inside preempt disabled
1248 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249
Ingo Molnarcae2ed92006-07-03 00:24:48 -07001250config DEBUG_LOCKING_API_SELFTESTS
1251 bool "Locking API boot-time self-tests"
1252 depends on DEBUG_KERNEL
1253 help
1254 Say Y here if you want the kernel to run a short self-test during
1255 bootup. The self-test checks whether common types of locking bugs
1256 are detected by debugging mechanisms or not. (if you disable
1257 lock debugging then those bugs wont be detected of course.)
1258 The following locking APIs are covered: spinlocks, rwlocks,
1259 mutexes and rwsems.
1260
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001261config LOCK_TORTURE_TEST
1262 tristate "torture tests for locking"
1263 depends on DEBUG_KERNEL
1264 select TORTURE_TEST
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001265 help
1266 This option provides a kernel module that runs torture tests
1267 on kernel locking primitives. The kernel module may be built
1268 after the fact on the running kernel to be tested, if desired.
1269
1270 Say Y here if you want kernel locking-primitive torture tests
1271 to be built into the kernel.
1272 Say M if you want these torture tests to build as a module.
1273 Say N if you are unsure.
1274
Chris Wilsonf2a5fec2016-12-01 11:47:06 +00001275config WW_MUTEX_SELFTEST
1276 tristate "Wait/wound mutex selftests"
1277 help
1278 This option provides a kernel module that runs tests on the
1279 on the struct ww_mutex locking API.
1280
1281 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1282 with this test harness.
1283
1284 Say M if you want these self tests to build as a module.
1285 Say N if you are unsure.
1286
Dave Hansen9eade162013-07-01 13:04:47 -07001287endmenu # lock debugging
1288
1289config TRACE_IRQFLAGS
1290 bool
1291 help
1292 Enables hooks to interrupt enabling and disabling for
1293 either tracing or lock debugging.
1294
Ingo Molnar8637c092006-07-03 00:24:38 -07001295config STACKTRACE
Dave Jones0c38e1f2014-08-29 15:18:35 -07001296 bool "Stack backtrace support"
Ingo Molnar8637c092006-07-03 00:24:38 -07001297 depends on STACKTRACE_SUPPORT
Dave Jones0c38e1f2014-08-29 15:18:35 -07001298 help
1299 This option causes the kernel to create a /proc/pid/stack for
1300 every process, showing its current stack trace.
1301 It is also used by various kernel debugging features that require
1302 stack trace generation.
Ingo Molnar8637c092006-07-03 00:24:38 -07001303
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001304config WARN_ALL_UNSEEDED_RANDOM
1305 bool "Warn for all uses of unseeded randomness"
1306 default n
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001307 help
1308 Some parts of the kernel contain bugs relating to their use of
1309 cryptographically secure random numbers before it's actually possible
1310 to generate those numbers securely. This setting ensures that these
1311 flaws don't go unnoticed, by enabling a message, should this ever
1312 occur. This will allow people with obscure setups to know when things
1313 are going wrong, so that they might contact developers about fixing
1314 it.
1315
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001316 Unfortunately, on some models of some architectures getting
1317 a fully seeded CRNG is extremely difficult, and so this can
1318 result in dmesg getting spammed for a surprisingly long
1319 time. This is really bad from a security perspective, and
1320 so architecture maintainers really need to do what they can
1321 to get the CRNG seeded sooner after the system is booted.
Thibaut Sautereau4c5d1142018-09-04 15:46:23 -07001322 However, since users cannot do anything actionable to
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001323 address this, by default the kernel will issue only a single
1324 warning for the first use of unseeded randomness.
1325
1326 Say Y here if you want to receive warnings for all uses of
1327 unseeded randomness. This will be of use primarily for
Thibaut Sautereau4c5d1142018-09-04 15:46:23 -07001328 those developers interested in improving the security of
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001329 Linux kernels running on their architecture (or
1330 subarchitecture).
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001331
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332config DEBUG_KOBJECT
1333 bool "kobject debugging"
1334 depends on DEBUG_KERNEL
1335 help
1336 If you say Y here, some extra kobject debugging messages will be sent
Mike Rapoportaca52c32018-10-30 15:07:44 -07001337 to the syslog.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001338
Russell Kingc817a672013-06-27 15:06:14 +01001339config DEBUG_KOBJECT_RELEASE
1340 bool "kobject release debugging"
Linus Torvalds2a999aa2013-10-29 08:33:36 -07001341 depends on DEBUG_OBJECTS_TIMERS
Russell Kingc817a672013-06-27 15:06:14 +01001342 help
1343 kobjects are reference counted objects. This means that their
1344 last reference count put is not predictable, and the kobject can
1345 live on past the point at which a driver decides to drop it's
1346 initial reference to the kobject gained on allocation. An
1347 example of this would be a struct device which has just been
1348 unregistered.
1349
1350 However, some buggy drivers assume that after such an operation,
1351 the memory backing the kobject can be immediately freed. This
1352 goes completely against the principles of a refcounted object.
1353
1354 If you say Y here, the kernel will delay the release of kobjects
1355 on the last reference count to improve the visibility of this
1356 kind of kobject release bug.
1357
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001358config HAVE_DEBUG_BUGVERBOSE
1359 bool
1360
Changbin Du3be5cbc2019-12-06 17:03:48 -08001361menu "Debug kernel data structures"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001362
Dave Jones199a9af2006-09-29 01:59:00 -07001363config DEBUG_LIST
1364 bool "Debug linked list manipulation"
Arnd Bergmann4520bcb2016-08-26 17:42:00 +02001365 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
Dave Jones199a9af2006-09-29 01:59:00 -07001366 help
1367 Enable this to turn on extended checks in the linked-list
1368 walking routines.
1369
1370 If unsure, say N.
1371
Davidlohr Bueso8e18fae2019-05-14 15:42:46 -07001372config DEBUG_PLIST
Dan Streetmanb8cfff62014-06-04 16:11:54 -07001373 bool "Debug priority linked list manipulation"
1374 depends on DEBUG_KERNEL
1375 help
1376 Enable this to turn on extended checks in the priority-ordered
1377 linked-list (plist) walking routines. This checks the entire
1378 list multiple times during each manipulation.
1379
1380 If unsure, say N.
1381
Jens Axboed6ec0842007-10-22 20:01:06 +02001382config DEBUG_SG
1383 bool "Debug SG table operations"
1384 depends on DEBUG_KERNEL
1385 help
1386 Enable this to turn on checks on scatter-gather tables. This can
1387 help find problems with drivers that do not properly initialize
1388 their sg tables.
1389
1390 If unsure, say N.
1391
Arjan van de Ven1b2439d2008-08-15 15:29:38 -07001392config DEBUG_NOTIFIERS
1393 bool "Debug notifier call chains"
1394 depends on DEBUG_KERNEL
1395 help
1396 Enable this to turn on sanity checking for notifier call chains.
1397 This is most useful for kernel developers to make sure that
1398 modules properly unregister themselves from notifier chains.
1399 This is a relatively cheap check but if you care about maximum
1400 performance, say N.
1401
Changbin Du3be5cbc2019-12-06 17:03:48 -08001402config BUG_ON_DATA_CORRUPTION
1403 bool "Trigger a BUG when data corruption is detected"
1404 select DEBUG_LIST
1405 help
1406 Select this option if the kernel should BUG when it encounters
1407 data corruption in kernel memory structures when they get checked
1408 for validity.
1409
1410 If unsure, say N.
1411
1412endmenu
1413
David Howellse0e81732009-09-02 09:13:40 +01001414config DEBUG_CREDENTIALS
1415 bool "Debug credential management"
1416 depends on DEBUG_KERNEL
1417 help
1418 Enable this to turn on some debug checking for credential
1419 management. The additional code keeps track of the number of
1420 pointers from task_structs to any given cred struct, and checks to
1421 see that this number never exceeds the usage count of the cred
1422 struct.
1423
1424 Furthermore, if SELinux is enabled, this also checks that the
1425 security pointer in the cred struct is never seen to be invalid.
1426
1427 If unsure, say N.
1428
Paul E. McKenney43a0a2a2017-05-17 09:19:44 -07001429source "kernel/rcu/Kconfig.debug"
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001430
Tejun Heof303fccb2016-02-09 17:59:38 -05001431config DEBUG_WQ_FORCE_RR_CPU
1432 bool "Force round-robin CPU selection for unbound work items"
1433 depends on DEBUG_KERNEL
1434 default n
1435 help
1436 Workqueue used to implicitly guarantee that work items queued
1437 without explicit CPU specified are put on the local CPU. This
1438 guarantee is no longer true and while local CPU is still
1439 preferred work items may be put on foreign CPUs. Kernel
1440 parameter "workqueue.debug_force_rr_cpu" is added to force
1441 round-robin CPU selection to flush out usages which depend on the
1442 now broken guarantee. This config option enables the debug
1443 feature by default. When enabled, memory and cache locality will
1444 be impacted.
1445
Tejun Heo870d6652008-08-25 19:47:25 +09001446config DEBUG_BLOCK_EXT_DEVT
Krzysztof Kozlowski68d4b3d2019-12-06 17:04:08 -08001447 bool "Force extended block device numbers and spread them"
Tejun Heo870d6652008-08-25 19:47:25 +09001448 depends on DEBUG_KERNEL
1449 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +02001450 default n
Tejun Heo870d6652008-08-25 19:47:25 +09001451 help
Tejun Heo0e11e342008-10-13 10:46:01 +02001452 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1453 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1454 YOU ARE DOING. Distros, please enable this and fix whatever
1455 is broken.
1456
Tejun Heo870d6652008-08-25 19:47:25 +09001457 Conventionally, block device numbers are allocated from
1458 predetermined contiguous area. However, extended block area
1459 may introduce non-contiguous block device numbers. This
1460 option forces most block device numbers to be allocated from
1461 the extended space and spreads them to discover kernel or
1462 userland code paths which assume predetermined contiguous
1463 device number allocation.
1464
Tejun Heo55dc7db2008-09-01 13:44:35 +02001465 Note that turning on this debug option shuffles all the
1466 device numbers for all IDE and SCSI devices including libata
1467 ones, so root partition specified using device number
1468 directly (via rdev or root=MAJ:MIN) won't work anymore.
1469 Textual device names (root=/dev/sdXn) will continue to work.
1470
Tejun Heo870d6652008-08-25 19:47:25 +09001471 Say N if you are unsure.
1472
Thomas Gleixner757c9892016-02-26 18:43:32 +00001473config CPU_HOTPLUG_STATE_CONTROL
1474 bool "Enable CPU hotplug state control"
1475 depends on DEBUG_KERNEL
1476 depends on HOTPLUG_CPU
1477 default n
1478 help
1479 Allows to write steps between "offline" and "online" to the CPUs
1480 sysfs target file so states can be stepped granular. This is a debug
1481 option for now as the hotplug machinery cannot be stopped and
1482 restarted at arbitrary points yet.
1483
1484 Say N if your are unsure.
1485
Changbin Du09a74952019-12-06 17:03:51 -08001486config LATENCYTOP
1487 bool "Latency measuring infrastructure"
1488 depends on DEBUG_KERNEL
1489 depends on STACKTRACE_SUPPORT
1490 depends on PROC_FS
1491 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1492 select KALLSYMS
1493 select KALLSYMS_ALL
1494 select STACKTRACE
1495 select SCHEDSTATS
1496 select SCHED_DEBUG
1497 help
1498 Enable this option if you want to use the LatencyTOP tool
1499 to find out which userspace is blocking on what kernel operations.
1500
1501source "kernel/trace/Kconfig"
1502
1503config PROVIDE_OHCI1394_DMA_INIT
1504 bool "Remote debugging over FireWire early on boot"
1505 depends on PCI && X86
1506 help
1507 If you want to debug problems which hang or crash the kernel early
1508 on boot and the crashing machine has a FireWire port, you can use
1509 this feature to remotely access the memory of the crashed machine
1510 over FireWire. This employs remote DMA as part of the OHCI1394
1511 specification which is now the standard for FireWire controllers.
1512
1513 With remote DMA, you can monitor the printk buffer remotely using
1514 firescope and access all memory below 4GB using fireproxy from gdb.
1515 Even controlling a kernel debugger is possible using remote DMA.
1516
1517 Usage:
1518
1519 If ohci1394_dma=early is used as boot parameter, it will initialize
1520 all OHCI1394 controllers which are found in the PCI config space.
1521
1522 As all changes to the FireWire bus such as enabling and disabling
1523 devices cause a bus reset and thereby disable remote DMA for all
1524 devices, be sure to have the cable plugged and FireWire enabled on
1525 the debugging host before booting the debug target for debugging.
1526
1527 This code (~1k) is freed after boot. By then, the firewire stack
1528 in charge of the OHCI-1394 controllers should be used instead.
1529
1530 See Documentation/debugging-via-ohci1394.txt for more information.
1531
Changbin Du045f6d72019-12-17 20:51:56 -08001532source "samples/Kconfig"
1533
1534config ARCH_HAS_DEVMEM_IS_ALLOWED
1535 bool
1536
1537config STRICT_DEVMEM
1538 bool "Filter access to /dev/mem"
1539 depends on MMU && DEVMEM
1540 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
1541 default y if PPC || X86 || ARM64
1542 help
1543 If this option is disabled, you allow userspace (root) access to all
1544 of memory, including kernel and userspace memory. Accidental
1545 access to this is obviously disastrous, but specific access can
1546 be used by people debugging the kernel. Note that with PAT support
1547 enabled, even in this case there are restrictions on /dev/mem
1548 use due to the cache aliasing requirements.
1549
1550 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1551 file only allows userspace access to PCI space and the BIOS code and
1552 data regions. This is sufficient for dosemu and X and all common
1553 users of /dev/mem.
1554
1555 If in doubt, say Y.
1556
1557config IO_STRICT_DEVMEM
1558 bool "Filter I/O access to /dev/mem"
1559 depends on STRICT_DEVMEM
1560 help
1561 If this option is disabled, you allow userspace (root) access to all
1562 io-memory regardless of whether a driver is actively using that
1563 range. Accidental access to this is obviously disastrous, but
1564 specific access can be used by people debugging kernel drivers.
1565
1566 If this option is switched on, the /dev/mem file only allows
1567 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1568 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1569 if the driver using a given range cannot be disabled.
1570
1571 If in doubt, say Y.
1572
1573menu "$(SRCARCH) Debugging"
1574
1575source "arch/$(SRCARCH)/Kconfig.debug"
1576
1577endmenu
1578
1579menu "Kernel Testing and Coverage"
1580
Changbin Du09a74952019-12-06 17:03:51 -08001581source "lib/kunit/Kconfig"
1582
Akinobu Mita8d438282012-07-30 14:43:02 -07001583config NOTIFIER_ERROR_INJECTION
1584 tristate "Notifier error injection"
1585 depends on DEBUG_KERNEL
1586 select DEBUG_FS
1587 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001588 This option provides the ability to inject artificial errors to
Akinobu Mita8d438282012-07-30 14:43:02 -07001589 specified notifier chain callbacks. It is useful to test the error
1590 handling of notifier call chain failures.
1591
1592 Say N if unsure.
1593
Akinobu Mita048b9c32012-07-30 14:43:07 -07001594config PM_NOTIFIER_ERROR_INJECT
1595 tristate "PM notifier error injection module"
1596 depends on PM && NOTIFIER_ERROR_INJECTION
1597 default m if PM_DEBUG
1598 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001599 This option provides the ability to inject artificial errors to
Akinobu Mita048b9c32012-07-30 14:43:07 -07001600 PM notifier chain callbacks. It is controlled through debugfs
1601 interface /sys/kernel/debug/notifier-error-inject/pm
1602
1603 If the notifier call chain should be failed with some events
1604 notified, write the error code to "actions/<notifier event>/error".
1605
1606 Example: Inject PM suspend error (-12 = -ENOMEM)
1607
1608 # cd /sys/kernel/debug/notifier-error-inject/pm/
1609 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1610 # echo mem > /sys/power/state
1611 bash: echo: write error: Cannot allocate memory
1612
1613 To compile this code as a module, choose M here: the module will
1614 be called pm-notifier-error-inject.
1615
1616 If unsure, say N.
1617
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001618config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1619 tristate "OF reconfig notifier error injection module"
1620 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001621 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001622 This option provides the ability to inject artificial errors to
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001623 OF reconfig notifier chain callbacks. It is controlled
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001624 through debugfs interface under
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001625 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001626
1627 If the notifier call chain should be failed with some events
1628 notified, write the error code to "actions/<notifier event>/error".
1629
1630 To compile this code as a module, choose M here: the module will
Akinobu Mitae12a95f2013-04-30 15:28:49 -07001631 be called of-reconfig-notifier-error-inject.
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001632
1633 If unsure, say N.
1634
Nikolay Aleksandrov02fff962015-11-28 13:45:28 +01001635config NETDEV_NOTIFIER_ERROR_INJECT
1636 tristate "Netdev notifier error injection module"
1637 depends on NET && NOTIFIER_ERROR_INJECTION
1638 help
1639 This option provides the ability to inject artificial errors to
1640 netdevice notifier chain callbacks. It is controlled through debugfs
1641 interface /sys/kernel/debug/notifier-error-inject/netdev
1642
1643 If the notifier call chain should be failed with some events
1644 notified, write the error code to "actions/<notifier event>/error".
1645
1646 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1647
1648 # cd /sys/kernel/debug/notifier-error-inject/netdev
1649 # echo -22 > actions/NETDEV_CHANGEMTU/error
1650 # ip link set eth0 mtu 1024
1651 RTNETLINK answers: Invalid argument
1652
1653 To compile this code as a module, choose M here: the module will
1654 be called netdev-notifier-error-inject.
1655
1656 If unsure, say N.
1657
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001658config FUNCTION_ERROR_INJECTION
1659 def_bool y
1660 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1661
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001662config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001663 bool "Fault-injection framework"
1664 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001665 help
1666 Provide fault-injection framework.
1667 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001668
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001669config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001670 bool "Fault-injection capability for kmalloc"
1671 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001672 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001673 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001674 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001675
Akinobu Mita933e3122006-12-08 02:39:45 -08001676config FAIL_PAGE_ALLOC
Qiujun Huang29b46fa2020-04-06 20:12:49 -07001677 bool "Fault-injection capability for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001678 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001679 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001680 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001681
Akinobu Mitac17bb492006-12-08 02:39:46 -08001682config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001683 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001684 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001685 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001686 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001687
Jens Axboe581d4e22008-09-14 05:56:33 -07001688config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d01432010-07-21 16:05:53 +09001689 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001690 depends on FAULT_INJECTION && BLOCK
1691 help
1692 Provide fault-injection capability on end IO handling. This
1693 will make the block layer "forget" an interrupt as configured,
1694 thus exercising the error handling.
1695
1696 Only works with drivers that use the generic timeout handling,
1697 for others it wont do anything.
1698
Davidlohr Buesoab51fba2015-06-29 23:26:02 -07001699config FAIL_FUTEX
1700 bool "Fault-injection capability for futexes"
1701 select DEBUG_FS
1702 depends on FAULT_INJECTION && FUTEX
1703 help
1704 Provide fault-injection capability for futexes.
1705
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001706config FAULT_INJECTION_DEBUG_FS
1707 bool "Debugfs entries for fault-injection capabilities"
1708 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1709 help
1710 Enable configuration of fault-injection capabilities via debugfs.
1711
Masami Hiramatsu4b1a29a2018-01-13 02:56:03 +09001712config FAIL_FUNCTION
1713 bool "Fault-injection capability for functions"
1714 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1715 help
1716 Provide function-based fault-injection capability.
1717 This will allow you to override a specific function with a return
1718 with given return value. As a result, function caller will see
1719 an error value and have to handle it. This is useful to test the
1720 error handling in various subsystems.
1721
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001722config FAIL_MMC_REQUEST
1723 bool "Fault-injection capability for MMC IO"
1724 depends on FAULT_INJECTION_DEBUG_FS && MMC
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001725 help
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001726 Provide fault-injection capability for MMC IO.
1727 This will make the mmc core return data errors. This is
1728 useful to test the error handling in the mmc block device
1729 and to test how the mmc host driver handles retries from
1730 the block device.
Akinobu Mita1df49002007-02-20 13:57:56 -08001731
1732config FAULT_INJECTION_STACKTRACE_FILTER
1733 bool "stacktrace filter for fault-injection capabilities"
1734 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001735 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001736 select STACKTRACE
Stefan Agnerf9b58e82018-09-30 23:02:33 +01001737 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
Akinobu Mita1df49002007-02-20 13:57:56 -08001738 help
1739 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001740
Changbin Du09a74952019-12-06 17:03:51 -08001741config ARCH_HAS_KCOV
1742 bool
Arjan van de Ven97455122008-01-25 21:08:34 +01001743 help
Changbin Du09a74952019-12-06 17:03:51 -08001744 An architecture should select this when it can successfully
1745 build and run with CONFIG_KCOV. This typically requires
1746 disabling instrumentation for some early boot code.
Arjan van de Ven97455122008-01-25 21:08:34 +01001747
Changbin Du09a74952019-12-06 17:03:51 -08001748config CC_HAS_SANCOV_TRACE_PC
1749 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001750
Changbin Du09a74952019-12-06 17:03:51 -08001751
1752config KCOV
1753 bool "Code coverage for fuzzing"
1754 depends on ARCH_HAS_KCOV
1755 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1756 select DEBUG_FS
1757 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001758 help
Changbin Du09a74952019-12-06 17:03:51 -08001759 KCOV exposes kernel code coverage information in a form suitable
1760 for coverage-guided fuzzing (randomized testing).
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001761
Changbin Du09a74952019-12-06 17:03:51 -08001762 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1763 different machines and across reboots. If you need stable PC values,
1764 disable RANDOMIZE_BASE.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001765
Changbin Du09a74952019-12-06 17:03:51 -08001766 For more details, see Documentation/dev-tools/kcov.rst.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001767
Changbin Du09a74952019-12-06 17:03:51 -08001768config KCOV_ENABLE_COMPARISONS
1769 bool "Enable comparison operands collection by KCOV"
1770 depends on KCOV
1771 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1772 help
1773 KCOV also exposes operands of every comparison in the instrumented
1774 code along with operand sizes and PCs of the comparison instructions.
1775 These operands can be used by fuzzing engines to improve the quality
1776 of fuzzing coverage.
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001777
Changbin Du09a74952019-12-06 17:03:51 -08001778config KCOV_INSTRUMENT_ALL
1779 bool "Instrument all code by default"
1780 depends on KCOV
1781 default y
1782 help
1783 If you are doing generic system call fuzzing (like e.g. syzkaller),
1784 then you will want to instrument the whole kernel and you should
1785 say y here. If you are doing more targeted fuzzing (like e.g.
1786 filesystem fuzzing with AFL) then you will want to enable coverage
1787 for more specific subsets of files, and should say n here.
Brendan Higgins84bc8092019-09-23 02:02:36 -07001788
Vincent Legolld3deafa2018-02-06 15:38:38 -08001789menuconfig RUNTIME_TESTING_MENU
1790 bool "Runtime Testing"
Anders Roxell908009e82018-02-21 14:46:05 -08001791 def_bool y
Vincent Legolld3deafa2018-02-06 15:38:38 -08001792
1793if RUNTIME_TESTING_MENU
Dave Hansen881c5142013-07-01 13:04:44 -07001794
1795config LKDTM
1796 tristate "Linux Kernel Dump Test Tool Module"
1797 depends on DEBUG_FS
Dave Hansen881c5142013-07-01 13:04:44 -07001798 help
1799 This module enables testing of the different dumping mechanisms by
1800 inducing system failures at predefined crash points.
1801 If you don't need it: say N
1802 Choose M here to compile this code as a module. The module will be
1803 called lkdtm.
1804
1805 Documentation on how to use the module can be found in
Mauro Carvalho Chehab10ffebb2019-06-12 14:52:44 -03001806 Documentation/fault-injection/provoke-crashes.rst
Dave Hansen881c5142013-07-01 13:04:44 -07001807
1808config TEST_LIST_SORT
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001809 tristate "Linked list sorting test"
1810 depends on DEBUG_KERNEL || m
Dave Hansen881c5142013-07-01 13:04:44 -07001811 help
1812 Enable this to turn on 'list_sort()' function test. This test is
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001813 executed only once during system boot (so affects only boot time),
1814 or at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001815
1816 If unsure, say N.
1817
Ian Rogers6e246282020-02-13 23:51:29 -08001818config TEST_MIN_HEAP
1819 tristate "Min heap test"
1820 depends on DEBUG_KERNEL || m
1821 help
1822 Enable this to turn on min heap function tests. This test is
1823 executed only once during system boot (so affects only boot time),
1824 or at module load time.
1825
1826 If unsure, say N.
1827
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001828config TEST_SORT
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001829 tristate "Array-based sort test"
1830 depends on DEBUG_KERNEL || m
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001831 help
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001832 This option enables the self-test function of 'sort()' at boot,
1833 or at module load time.
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001834
1835 If unsure, say N.
1836
Dave Hansen881c5142013-07-01 13:04:44 -07001837config KPROBES_SANITY_TEST
1838 bool "Kprobes sanity tests"
1839 depends on DEBUG_KERNEL
1840 depends on KPROBES
Dave Hansen881c5142013-07-01 13:04:44 -07001841 help
1842 This option provides for testing basic kprobes functionality on
Masami Hiramatsu5a6cf772018-06-20 01:05:07 +09001843 boot. Samples of kprobe and kretprobe are inserted and
Dave Hansen881c5142013-07-01 13:04:44 -07001844 verified for functionality.
1845
1846 Say N if you are unsure.
1847
1848config BACKTRACE_SELF_TEST
1849 tristate "Self test for the backtrace code"
1850 depends on DEBUG_KERNEL
Dave Hansen881c5142013-07-01 13:04:44 -07001851 help
1852 This option provides a kernel module that can be used to test
1853 the kernel stack backtrace code. This option is not useful
1854 for distributions or general kernels, but only for kernel
1855 developers working on architecture code.
1856
1857 Note that if you want to also test saved backtraces, you will
1858 have to enable STACKTRACE as well.
1859
1860 Say N if you are unsure.
1861
Michel Lespinasse910a7422012-10-08 16:30:39 -07001862config RBTREE_TEST
1863 tristate "Red-Black tree test"
Cody P Schafer7c993e12013-09-11 14:25:19 -07001864 depends on DEBUG_KERNEL
Michel Lespinasse910a7422012-10-08 16:30:39 -07001865 help
1866 A benchmark measuring the performance of the rbtree library.
1867 Also includes rbtree invariant checks.
1868
Ferdinand Blomqvist4b4f3ac2019-06-20 17:10:33 +03001869config REED_SOLOMON_TEST
1870 tristate "Reed-Solomon library test"
1871 depends on DEBUG_KERNEL || m
1872 select REED_SOLOMON
1873 select REED_SOLOMON_ENC16
1874 select REED_SOLOMON_DEC16
1875 help
1876 This option enables the self-test function of rslib at boot,
1877 or at module load time.
1878
1879 If unsure, say N.
1880
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001881config INTERVAL_TREE_TEST
1882 tristate "Interval tree test"
Davidlohr Bueso0f789b62017-07-10 15:51:43 -07001883 depends on DEBUG_KERNEL
Chris Wilsona88cc102014-03-17 12:21:54 +00001884 select INTERVAL_TREE
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001885 help
1886 A benchmark measuring the performance of the interval tree library
1887
Greg Thelen623fd802013-11-12 15:08:34 -08001888config PERCPU_TEST
1889 tristate "Per cpu operations test"
1890 depends on m && DEBUG_KERNEL
1891 help
1892 Enable this option to build test module which validates per-cpu
1893 operations.
1894
1895 If unsure, say N.
1896
Dave Hansen881c5142013-07-01 13:04:44 -07001897config ATOMIC64_SELFTEST
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001898 tristate "Perform an atomic64_t self-test"
Dave Hansen881c5142013-07-01 13:04:44 -07001899 help
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001900 Enable this option to test the atomic64_t functions at boot or
1901 at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001902
1903 If unsure, say N.
1904
1905config ASYNC_RAID6_TEST
1906 tristate "Self test for hardware accelerated raid6 recovery"
1907 depends on ASYNC_RAID6_RECOV
1908 select ASYNC_MEMCPY
1909 ---help---
1910 This is a one-shot self test that permutes through the
1911 recovery of all the possible two disk failure scenarios for a
1912 N-disk array. Recovery is performed with the asynchronous
1913 raid6 recovery routines, and will optionally use an offload
1914 engine if one is available.
1915
1916 If unsure, say N.
1917
Andy Shevchenko64d1d772015-02-12 15:02:21 -08001918config TEST_HEXDUMP
1919 tristate "Test functions located in the hexdump module at runtime"
1920
Dave Hansen881c5142013-07-01 13:04:44 -07001921config TEST_STRING_HELPERS
1922 tristate "Test functions located in the string_helpers module at runtime"
1923
Tobin C. Harding0b0600c2019-04-05 12:58:59 +11001924config TEST_STRSCPY
1925 tristate "Test strscpy*() family of functions at runtime"
1926
Dave Hansen881c5142013-07-01 13:04:44 -07001927config TEST_KSTRTOX
1928 tristate "Test kstrto*() family of functions at runtime"
1929
Rasmus Villemoes707cc722015-11-06 16:30:29 -08001930config TEST_PRINTF
1931 tristate "Test printf() family of functions at runtime"
1932
David Decotigny5fd003f2016-02-19 09:24:00 -05001933config TEST_BITMAP
1934 tristate "Test bitmap_*() family of functions at runtime"
David Decotigny5fd003f2016-02-19 09:24:00 -05001935 help
1936 Enable this option to test the bitmap functions at boot.
1937
1938 If unsure, say N.
1939
Johannes Berg0e2dc702018-06-20 08:58:30 +02001940config TEST_BITFIELD
1941 tristate "Test bitfield functions at runtime"
1942 help
1943 Enable this option to test the bitfield functions at boot.
1944
1945 If unsure, say N.
1946
Andy Shevchenkocfaff0e2016-05-30 17:40:41 +03001947config TEST_UUID
1948 tristate "Test functions located in the uuid module at runtime"
1949
Matthew Wilcoxad3d6c72017-11-07 14:57:46 -05001950config TEST_XARRAY
1951 tristate "Test the XArray code at runtime"
1952
Rasmus Villemoes455a35a2018-05-08 00:36:28 +02001953config TEST_OVERFLOW
1954 tristate "Test check_*_overflow() functions at runtime"
1955
Thomas Graf7e1e7762014-08-02 11:47:44 +02001956config TEST_RHASHTABLE
Geert Uytterhoeven9d6dbe12015-01-29 15:40:25 +01001957 tristate "Perform selftest on resizable hash table"
Thomas Graf7e1e7762014-08-02 11:47:44 +02001958 help
1959 Enable this option to test the rhashtable functions at boot.
1960
1961 If unsure, say N.
1962
George Spelvin468a9422016-05-26 22:11:51 -04001963config TEST_HASH
1964 tristate "Perform selftest on hash functions"
George Spelvin468a9422016-05-26 22:11:51 -04001965 help
Jason A. Donenfeld2c956a62017-01-08 13:54:00 +01001966 Enable this option to test the kernel's integer (<linux/hash.h>),
1967 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
1968 hash functions on boot (or module load).
George Spelvin468a9422016-05-26 22:11:51 -04001969
1970 This is intended to help people writing architecture-specific
1971 optimized versions. If unsure, say N.
1972
Matthew Wilcox8ab8ba32018-06-18 16:59:29 -04001973config TEST_IDA
1974 tristate "Perform selftest on IDA functions"
1975
Jiri Pirko44091d22017-02-03 10:29:06 +01001976config TEST_PARMAN
1977 tristate "Perform selftest on priority array manager"
Jiri Pirko44091d22017-02-03 10:29:06 +01001978 depends on PARMAN
1979 help
1980 Enable this option to test priority array manager on boot
1981 (or module load).
1982
1983 If unsure, say N.
1984
Daniel Lezcano6aed82d2019-05-27 22:55:19 +02001985config TEST_IRQ_TIMINGS
1986 bool "IRQ timings selftest"
1987 depends on IRQ_TIMINGS
1988 help
1989 Enable this option to test the irq timings code on boot.
1990
1991 If unsure, say N.
1992
Valentin Rothberg8a6f0b42014-10-13 15:51:38 -07001993config TEST_LKM
Kees Cook93e9ef82014-01-23 15:54:37 -08001994 tristate "Test module loading with 'hello world' module"
Kees Cook93e9ef82014-01-23 15:54:37 -08001995 depends on m
1996 help
1997 This builds the "test_module" module that emits "Hello, world"
1998 on printk when loaded. It is designed to be used for basic
1999 evaluation of the module loading subsystem (for example when
2000 validating module verification). It lacks any extra dependencies,
2001 and will not normally be loaded by the system unless explicitly
2002 requested by name.
2003
2004 If unsure, say N.
2005
Uladzislau Rezki (Sony)3f21a6b2019-03-05 15:43:34 -08002006config TEST_VMALLOC
2007 tristate "Test module for stress/performance analysis of vmalloc allocator"
2008 default n
2009 depends on MMU
2010 depends on m
2011 help
2012 This builds the "test_vmalloc" module that should be used for
2013 stress and performance analysis. So, any new change for vmalloc
2014 subsystem can be evaluated from performance and stability point
2015 of view.
2016
2017 If unsure, say N.
2018
Kees Cook3e2a4c12014-01-23 15:54:38 -08002019config TEST_USER_COPY
2020 tristate "Test user/kernel boundary protections"
Kees Cook3e2a4c12014-01-23 15:54:38 -08002021 depends on m
2022 help
2023 This builds the "test_user_copy" module that runs sanity checks
2024 on the copy_to/from_user infrastructure, making sure basic
2025 user/kernel boundary testing is working. If it fails to load,
2026 a regression has been detected in the user/kernel memory boundary
2027 protections.
2028
2029 If unsure, say N.
2030
Alexei Starovoitov64a89462014-05-08 14:10:52 -07002031config TEST_BPF
2032 tristate "Test BPF filter functionality"
Randy Dunlap98920ba2014-05-13 09:58:44 -07002033 depends on m && NET
Alexei Starovoitov64a89462014-05-08 14:10:52 -07002034 help
2035 This builds the "test_bpf" module that runs various test vectors
2036 against the BPF interpreter or BPF JIT compiler depending on the
2037 current setting. This is in particular useful for BPF JIT compiler
2038 development, but also to run regression tests against changes in
Alexei Starovoitov3c731eb2014-09-26 00:17:07 -07002039 the interpreter code. It also enables test stubs for eBPF maps and
2040 verifier used by user space verifier testsuite.
Alexei Starovoitov64a89462014-05-08 14:10:52 -07002041
2042 If unsure, say N.
2043
Mahesh Bandewar509e56b2019-07-01 14:39:01 -07002044config TEST_BLACKHOLE_DEV
2045 tristate "Test blackhole netdev functionality"
2046 depends on m && NET
2047 help
2048 This builds the "test_blackhole_dev" module that validates the
2049 data path through this blackhole netdev.
2050
2051 If unsure, say N.
2052
Yury Norovdceeb3e2018-02-06 15:38:27 -08002053config FIND_BIT_BENCHMARK
Yury Norov4441fca2017-11-17 15:28:31 -08002054 tristate "Test find_bit functions"
Yury Norov4441fca2017-11-17 15:28:31 -08002055 help
2056 This builds the "test_find_bit" module that measure find_*_bit()
2057 functions performance.
2058
2059 If unsure, say N.
2060
Kees Cook0a8adf52014-07-14 14:38:12 -07002061config TEST_FIRMWARE
2062 tristate "Test firmware loading via userspace interface"
Kees Cook0a8adf52014-07-14 14:38:12 -07002063 depends on FW_LOADER
2064 help
2065 This builds the "test_firmware" module that creates a userspace
2066 interface for testing firmware loading. This can be used to
2067 control the triggering of firmware loading without needing an
2068 actual firmware-using device. The contents can be rechecked by
2069 userspace.
2070
2071 If unsure, say N.
2072
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07002073config TEST_SYSCTL
2074 tristate "sysctl test driver"
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07002075 depends on PROC_SYSCTL
2076 help
2077 This builds the "test_sysctl" module. This driver enables to test the
2078 proc sysctl interfaces available to drivers safely without affecting
2079 production knobs which might alter system functionality.
2080
2081 If unsure, say N.
2082
Iurii Zaikin2cb80db2019-09-23 02:02:47 -07002083config SYSCTL_KUNIT_TEST
Alan Maguirec475c772020-01-06 22:28:20 +00002084 tristate "KUnit test for sysctl"
Iurii Zaikin2cb80db2019-09-23 02:02:47 -07002085 depends on KUNIT
2086 help
2087 This builds the proc sysctl unit test, which runs on boot.
2088 Tests the API contract and implementation correctness of sysctl.
2089 For more information on KUnit and unit tests in general please refer
2090 to the KUnit documentation in Documentation/dev-tools/kunit/.
2091
2092 If unsure, say N.
2093
David Gowea2dd7c2019-10-24 15:46:31 -07002094config LIST_KUNIT_TEST
Alan Maguirec475c772020-01-06 22:28:20 +00002095 tristate "KUnit Test for Kernel Linked-list structures"
David Gowea2dd7c2019-10-24 15:46:31 -07002096 depends on KUNIT
2097 help
2098 This builds the linked list KUnit test suite.
2099 It tests that the API and basic functionality of the list_head type
2100 and associated macros.
2101
2102 KUnit tests run during boot and output the results to the debug log
2103 in TAP format (http://testanything.org/). Only useful for kernel devs
2104 running the KUnit test harness, and not intended for inclusion into a
2105 production build.
2106
2107 For more information on KUnit and unit tests in general please refer
2108 to the KUnit documentation in Documentation/dev-tools/kunit/.
2109
2110 If unsure, say N.
2111
David Rileye704f932014-06-16 14:58:32 -07002112config TEST_UDELAY
2113 tristate "udelay test driver"
David Rileye704f932014-06-16 14:58:32 -07002114 help
2115 This builds the "udelay_test" module that helps to make sure
2116 that udelay() is working properly.
2117
2118 If unsure, say N.
2119
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02002120config TEST_STATIC_KEYS
2121 tristate "Test static keys"
Jason Baron579e1ac2015-07-30 03:59:44 +00002122 depends on m
2123 help
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02002124 Test the static key interfaces.
Jason Baron579e1ac2015-07-30 03:59:44 +00002125
2126 If unsure, say N.
2127
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002128config TEST_KMOD
2129 tristate "kmod stress tester"
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002130 depends on m
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002131 depends on NETDEVICES && NET_CORE && INET # for TUN
YueHaibingae3d6a32019-04-25 22:23:44 -07002132 depends on BLOCK
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002133 select TEST_LKM
2134 select XFS_FS
2135 select TUN
2136 select BTRFS_FS
2137 help
2138 Test the kernel's module loading mechanism: kmod. kmod implements
2139 support to load modules using the Linux kernel's usermode helper.
2140 This test provides a series of tests against kmod.
2141
2142 Although technically you can either build test_kmod as a module or
2143 into the kernel we disallow building it into the kernel since
2144 it stress tests request_module() and this will very likely cause
2145 some issues by taking over precious threads available from other
2146 module load requests, ultimately this could be fatal.
2147
2148 To run tests run:
2149
2150 tools/testing/selftests/kmod/kmod.sh --help
2151
2152 If unsure, say N.
2153
Florian Fainellie4dace32017-09-08 16:15:31 -07002154config TEST_DEBUG_VIRTUAL
2155 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2156 depends on DEBUG_VIRTUAL
2157 help
2158 Test the kernel's ability to detect incorrect calls to
2159 virt_to_phys() done against the non-linear part of the
2160 kernel's virtual address map.
2161
2162 If unsure, say N.
2163
Alexander Shishkince76d932018-10-05 15:43:05 +03002164config TEST_MEMCAT_P
2165 tristate "Test memcat_p() helper function"
2166 help
2167 Test the memcat_p() helper for correctly merging two
2168 pointer arrays together.
2169
2170 If unsure, say N.
2171
Joe Lawrencea2818ee2019-01-09 13:43:29 +01002172config TEST_LIVEPATCH
2173 tristate "Test livepatching"
2174 default n
Joe Lawrencebae05432019-01-31 11:41:24 -05002175 depends on DYNAMIC_DEBUG
Joe Lawrencea2818ee2019-01-09 13:43:29 +01002176 depends on LIVEPATCH
2177 depends on m
2178 help
2179 Test kernel livepatching features for correctness. The tests will
2180 load test modules that will be livepatched in various scenarios.
2181
2182 To run all the livepatching tests:
2183
2184 make -C tools/testing/selftests TARGETS=livepatch run_tests
2185
2186 Alternatively, individual tests may be invoked:
2187
2188 tools/testing/selftests/livepatch/test-callbacks.sh
2189 tools/testing/selftests/livepatch/test-livepatch.sh
2190 tools/testing/selftests/livepatch/test-shadow-vars.sh
2191
2192 If unsure, say N.
2193
Jiri Pirko0a020d42018-11-14 08:22:28 +00002194config TEST_OBJAGG
2195 tristate "Perform selftest on object aggreration manager"
2196 default n
2197 depends on OBJAGG
2198 help
2199 Enable this option to test object aggregation manager on boot
2200 (or module load).
2201
Jiri Pirko0a020d42018-11-14 08:22:28 +00002202
Kees Cook50ceaa95e2019-01-23 12:24:32 -07002203config TEST_STACKINIT
2204 tristate "Test level of stack variable initialization"
2205 help
2206 Test if the kernel is zero-initializing stack variables and
2207 padding. Coverage is controlled by compiler flags,
2208 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2209 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2210
2211 If unsure, say N.
2212
Alexander Potapenko5015a302019-07-16 16:27:27 -07002213config TEST_MEMINIT
2214 tristate "Test heap/page initialization"
2215 help
2216 Test if the kernel is zero-initializing heap and page allocations.
2217 This can be useful to test init_on_alloc and init_on_free features.
2218
2219 If unsure, say N.
2220
Vincent Legolld3deafa2018-02-06 15:38:38 -08002221endif # RUNTIME_TESTING_MENU
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002222
2223config MEMTEST
2224 bool "Memtest"
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002225 ---help---
2226 This option adds a kernel parameter 'memtest', which allows memtest
2227 to be set.
2228 memtest=0, mean disabled; -- default
2229 memtest=1, mean do 1 test pattern;
2230 ...
2231 memtest=17, mean do 17 test patterns.
2232 If you are unsure how to answer this question, answer N.
2233
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002234
Christoph Hellwig06ec64b2018-07-31 13:39:31 +02002235
Branden Bonabyaf9ca6f2019-10-03 17:01:49 -04002236config HYPERV_TESTING
2237 bool "Microsoft Hyper-V driver testing"
2238 default n
2239 depends on HYPERV && DEBUG_FS
2240 help
2241 Select this option to enable Hyper-V vmbus testing.
2242
Changbin Du045f6d72019-12-17 20:51:56 -08002243endmenu # "Kernel Testing and Coverage"
2244
Christoph Hellwig06ec64b2018-07-31 13:39:31 +02002245endmenu # Kernel hacking