blob: 6c164cdbef4a7dccc9cbb5422c7b1cd9bc2bd3e2 [file] [log] [blame]
Christoph Hellwig06ec64b2018-07-31 13:39:31 +02001menu "Kernel hacking"
2
Dave Hansen604ff0d2013-07-01 13:04:49 -07003menu "printk and dmesg options"
Linus Torvalds1da177e2005-04-16 15:20:36 -07004
5config PRINTK_TIME
6 bool "Show timing information on printks"
Randy Dunlapd3b8b6e2006-12-06 20:36:38 -08007 depends on PRINTK
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 help
Kay Sievers649e6ee2012-05-10 04:30:45 +02009 Selecting this option causes time stamps of the printk()
10 messages to be added to the output of the syslog() system
11 call and at the console.
12
13 The timestamp is always recorded internally, and exported
14 to /dev/kmsg. This flag just specifies if the timestamp should
15 be included, not that the timestamp is recorded.
16
17 The behavior is also controlled by the kernel command line
Mauro Carvalho Chehab8c27ceff32016-10-18 10:12:27 -020018 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
Linus Torvalds1da177e2005-04-16 15:20:36 -070019
Olof Johanssona8cfdc62016-12-12 16:45:56 -080020config CONSOLE_LOGLEVEL_DEFAULT
21 int "Default console loglevel (1-15)"
22 range 1 15
23 default "7"
24 help
25 Default loglevel to determine what will be printed on the console.
26
27 Setting a default here is equivalent to passing in loglevel=<x> in
28 the kernel bootargs. loglevel=<x> continues to override whatever
29 value is specified here as well.
30
Borislav Petkov50f4d9b2016-12-19 16:23:15 -080031 Note: This does not affect the log level of un-prefixed printk()
Olof Johanssona8cfdc62016-12-12 16:45:56 -080032 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
33 option.
34
Hans de Goede22eceb82018-06-19 13:57:26 +020035config CONSOLE_LOGLEVEL_QUIET
36 int "quiet console loglevel (1-15)"
37 range 1 15
38 default "4"
39 help
40 loglevel to use when "quiet" is passed on the kernel commandline.
41
42 When "quiet" is passed on the kernel commandline this loglevel
43 will be used as the loglevel. IOW passing "quiet" will be the
44 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
45
Alex Elder42a9dc02014-08-06 16:09:01 -070046config MESSAGE_LOGLEVEL_DEFAULT
Mandeep Singh Baines5af5bcb2011-03-22 16:34:23 -070047 int "Default message log level (1-7)"
48 range 1 7
49 default "4"
50 help
51 Default log level for printk statements with no specified priority.
52
53 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
54 that are auditing their logs closely may want to set it to a lower
55 priority.
56
Olof Johanssona8cfdc62016-12-12 16:45:56 -080057 Note: This does not affect what message level gets printed on the console
58 by default. To change that, use loglevel=<x> in the kernel bootargs,
59 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
60
Dave Hansen604ff0d2013-07-01 13:04:49 -070061config BOOT_PRINTK_DELAY
62 bool "Delay each boot printk message by N milliseconds"
63 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
64 help
65 This build option allows you to read kernel boot messages
66 by inserting a short delay after each one. The delay is
67 specified in milliseconds on the kernel command line,
68 using "boot_delay=N".
69
70 It is likely that you would also need to use "lpj=M" to preset
71 the "loops per jiffie" value.
72 See a previous boot log for the "lpj" value to use for your
73 system, and then set "lpj=M" before setting "boot_delay=N".
74 NOTE: Using this option may adversely affect SMP systems.
75 I.e., processors other than the first one may not boot up.
76 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
77 what it believes to be lockup conditions.
78
79config DYNAMIC_DEBUG
80 bool "Enable dynamic printk() support"
81 default n
82 depends on PRINTK
83 depends on DEBUG_FS
84 help
85
86 Compiles debug level messages into the kernel, which would not
87 otherwise be available at runtime. These messages can then be
88 enabled/disabled based on various levels of scope - per source file,
89 function, module, format string, and line number. This mechanism
90 implicitly compiles in all pr_debug() and dev_dbg() calls, which
91 enlarges the kernel text size by about 2%.
92
93 If a source file is compiled with DEBUG flag set, any
94 pr_debug() calls in it are enabled by default, but can be
95 disabled at runtime as below. Note that DEBUG flag is
96 turned on by many CONFIG_*DEBUG* options.
97
98 Usage:
99
100 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
101 which is contained in the 'debugfs' filesystem. Thus, the debugfs
102 filesystem must first be mounted before making use of this feature.
103 We refer the control file as: <debugfs>/dynamic_debug/control. This
104 file contains a list of the debug statements that can be enabled. The
105 format for each line of the file is:
106
107 filename:lineno [module]function flags format
108
109 filename : source file of the debug statement
110 lineno : line number of the debug statement
111 module : module that contains the debug statement
112 function : function that contains the debug statement
113 flags : '=p' means the line is turned 'on' for printing
114 format : the format used for the debug statement
115
116 From a live system:
117
118 nullarbor:~ # cat <debugfs>/dynamic_debug/control
119 # filename:lineno [module]function flags format
120 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
121 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
122 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
123
124 Example usage:
125
126 // enable the message at line 1603 of file svcsock.c
127 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
128 <debugfs>/dynamic_debug/control
129
130 // enable all the messages in file svcsock.c
131 nullarbor:~ # echo -n 'file svcsock.c +p' >
132 <debugfs>/dynamic_debug/control
133
134 // enable all the messages in the NFS server module
135 nullarbor:~ # echo -n 'module nfsd +p' >
136 <debugfs>/dynamic_debug/control
137
138 // enable all 12 messages in the function svc_process()
139 nullarbor:~ # echo -n 'func svc_process +p' >
140 <debugfs>/dynamic_debug/control
141
142 // disable all 12 messages in the function svc_process()
143 nullarbor:~ # echo -n 'func svc_process -p' >
144 <debugfs>/dynamic_debug/control
145
Hans Holmbergf8998c22017-03-16 09:37:32 +0100146 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
147 information.
Dave Hansen604ff0d2013-07-01 13:04:49 -0700148
Patrick Daly0585b782019-06-07 17:00:54 -0700149config DEBUG_CONSOLE_UNHASHED_POINTERS
150 bool "Display unhashed kernel pointers"
151 depends on DEBUG_KERNEL
152 help
153 Pointers %p and %pK are normally hashed prior to being displayed to
154 prevent leaking kernel addresses. On debug builds, always print
155 actual pointer values, ignoring the kptr_restrict setting.
156 Not to be enabled on production builds.
157
Dave Hansen604ff0d2013-07-01 13:04:49 -0700158endmenu # "printk and dmesg options"
159
Dave Hansen6dfc0662013-07-01 13:04:46 -0700160menu "Compile-time checks and compiler options"
161
162config DEBUG_INFO
163 bool "Compile the kernel with debug info"
Linus Torvalds12b13832014-02-04 12:20:01 -0800164 depends on DEBUG_KERNEL && !COMPILE_TEST
Dave Hansen6dfc0662013-07-01 13:04:46 -0700165 help
166 If you say Y here the resulting kernel image will include
167 debugging info resulting in a larger kernel image.
168 This adds debug symbols to the kernel and modules (gcc -g), and
169 is needed if you intend to use kernel crashdump or binary object
170 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
171 Say Y here only if you plan to debug the kernel.
172
173 If unsure, say N.
174
175config DEBUG_INFO_REDUCED
176 bool "Reduce debugging information"
177 depends on DEBUG_INFO
178 help
179 If you say Y here gcc is instructed to generate less debugging
180 information for structure types. This means that tools that
181 need full debugging information (like kgdb or systemtap) won't
182 be happy. But if you merely need debugging information to
183 resolve line numbers there is no loss. Advantage is that
184 build directory object sizes shrink dramatically over a full
185 DEBUG_INFO build and compile times are reduced too.
186 Only works with newer gcc versions.
187
Andi Kleen866ced92014-07-30 20:50:18 +0200188config DEBUG_INFO_SPLIT
189 bool "Produce split debuginfo in .dwo files"
Arnd Bergmanna687a532018-03-07 23:30:54 +0100190 depends on DEBUG_INFO
Andi Kleen866ced92014-07-30 20:50:18 +0200191 help
192 Generate debug info into separate .dwo files. This significantly
193 reduces the build directory size for builds with DEBUG_INFO,
194 because it stores the information only once on disk in .dwo
195 files instead of multiple times in object files and executables.
196 In addition the debug information is also compressed.
197
198 Requires recent gcc (4.7+) and recent gdb/binutils.
199 Any tool that packages or reads debug information would need
200 to know about the .dwo files and include them.
201 Incompatible with older versions of ccache.
202
Andi Kleenbfaf2dd2014-07-30 20:50:19 +0200203config DEBUG_INFO_DWARF4
204 bool "Generate dwarf4 debuginfo"
205 depends on DEBUG_INFO
206 help
207 Generate dwarf4 debug info. This requires recent versions
208 of gcc and gdb. It makes the debug information larger.
209 But it significantly improves the success of resolving
210 variables in gdb on optimized code.
211
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800212config GDB_SCRIPTS
213 bool "Provide GDB scripts for kernel debugging"
214 depends on DEBUG_INFO
215 help
216 This creates the required links to GDB helper scripts in the
217 build directory. If you load vmlinux into gdb, the helper
218 scripts will be automatically imported by gdb as well, and
219 additional functions are available to analyze a Linux kernel
Andreas Platschek700199b02016-12-14 15:05:40 -0800220 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
221 for further details.
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800222
Andrew Mortoncebc04b2006-08-14 22:43:18 -0700223config ENABLE_MUST_CHECK
224 bool "Enable __must_check logic"
225 default y
226 help
227 Enable the __must_check logic in the kernel build. Disable this to
228 suppress the "warning: ignoring return value of 'foo', declared with
229 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
Andi Kleen35bb5b12008-02-22 15:15:03 +0100231config FRAME_WARN
232 int "Warn for stack frames larger than (needs gcc 4.4)"
233 range 0 8192
Arnd Bergmanne7c52b82018-02-06 15:41:41 -0800234 default 3072 if KASAN_EXTRA
Kees Cook0e07f662016-10-27 17:46:41 -0700235 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
Helge Deller432654d2017-09-11 21:41:43 +0200236 default 1280 if (!64BIT && PARISC)
237 default 1024 if (!64BIT && !PARISC)
Andi Kleen35bb5b12008-02-22 15:15:03 +0100238 default 2048 if 64BIT
239 help
240 Tell gcc to warn at build time for stack frames larger than this.
241 Setting this too low will cause a lot of warnings.
242 Setting it to 0 disables the warning.
243 Requires gcc 4.4
244
Randy Dunlap99657c72009-09-18 12:49:22 -0700245config STRIP_ASM_SYMS
246 bool "Strip assembler-generated symbols during link"
247 default n
248 help
249 Strip internal assembler-generated symbols during a link (symbols
250 that look like '.Lxxx') so they don't pollute the output of
251 get_wchan() and suchlike.
252
Andi Kleen1873e872012-03-28 11:51:18 -0700253config READABLE_ASM
254 bool "Generate readable assembler code"
255 depends on DEBUG_KERNEL
256 help
257 Disable some compiler optimizations that tend to generate human unreadable
258 assembler output. This may make the kernel slightly slower, but it helps
259 to keep kernel developers who have to stare a lot at assembler listings
260 sane.
261
Arjan van de Venf71d20e2006-06-28 04:26:45 -0700262config UNUSED_SYMBOLS
263 bool "Enable unused/obsolete exported symbols"
264 default y if X86
265 help
266 Unused but exported symbols make the kernel needlessly bigger. For
267 that reason most of these unused exports will soon be removed. This
268 option is provided temporarily to provide a transition period in case
269 some external kernel module needs one of these symbols anyway. If you
270 encounter such a case in your module, consider if you are actually
271 using the right API. (rationale: since nobody in the kernel is using
272 this in a module, there is a pretty good chance it's actually the
273 wrong interface to use). If you really need the symbol, please send a
274 mail to the linux kernel mailing list mentioning the symbol and why
275 you really need it, and what the merge plan to the mainline kernel for
276 your module is.
277
Joonsoo Kim48c96a32014-12-12 16:56:01 -0800278config PAGE_OWNER
279 bool "Track page owner"
280 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
281 select DEBUG_FS
282 select STACKTRACE
Joonsoo Kimf2ca0b52016-07-26 15:23:55 -0700283 select STACKDEPOT
Joonsoo Kim48c96a32014-12-12 16:56:01 -0800284 select PAGE_EXTENSION
285 help
286 This keeps track of what call chain is the owner of a page, may
287 help to find bare alloc_page(s) leaks. Even if you include this
288 feature on your build, it is disabled in default. You should pass
289 "page_owner=on" to boot parameter in order to enable it. Eats
290 a fair amount of memory if enabled. See tools/vm/page_owner_sort.c
291 for user-space helper.
292
293 If unsure, say N.
294
Trilok Soni6fe73962016-04-20 18:12:51 -0700295config PAGE_OWNER_ENABLE_DEFAULT
296 bool "Enable Track page owner by default"
297 depends on PAGE_OWNER
298 help
299 This keeps track of what call chain is the owner of a page, may
300 help to find bare alloc_page(s) leaks. If you include this
301 feature on your build, it is enabled by default. You should pass
302 "page_owner=off" to boot parameter in order to disable it. Eats
303 a fair amount of memory if enabled. See tools/vm/page_owner_sort.c
304 for user-space helper.
305
Don Mullisbf4735a2006-12-10 02:18:37 -0800306config DEBUG_FS
307 bool "Debug Filesystem"
Don Mullisbf4735a2006-12-10 02:18:37 -0800308 help
309 debugfs is a virtual file system that kernel developers use to put
310 debugging files into. Enable this option to be able to read and
311 write to these files.
312
Robert P. J. Dayff543332008-05-20 00:06:00 +0200313 For detailed documentation on the debugfs API, see
Mauro Carvalho Chehabe1b4fc72017-05-14 12:04:55 -0300314 Documentation/filesystems/.
Robert P. J. Dayff543332008-05-20 00:06:00 +0200315
Don Mullisbf4735a2006-12-10 02:18:37 -0800316 If unsure, say N.
317
318config HEADERS_CHECK
319 bool "Run 'make headers_check' when building vmlinux"
320 depends on !UML
321 help
322 This option will extract the user-visible kernel headers whenever
323 building the kernel, and will run basic sanity checks on them to
324 ensure that exported files do not attempt to include files which
325 were not exported, etc.
326
327 If you're making modifications to header files which are
328 relevant for userspace, say 'Y', and check the headers
329 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
330 your build tree), to make sure they're suitable.
331
Sam Ravnborg91341d42008-01-21 21:31:44 +0100332config DEBUG_SECTION_MISMATCH
333 bool "Enable full Section mismatch analysis"
Sam Ravnborg91341d42008-01-21 21:31:44 +0100334 help
335 The section mismatch analysis checks if there are illegal
336 references from one section to another section.
Michael Wittene809ab02011-04-17 04:08:48 +0000337 During linktime or runtime, some sections are dropped;
338 any use of code/data previously in these sections would
Sam Ravnborg91341d42008-01-21 21:31:44 +0100339 most likely result in an oops.
Michael Wittene809ab02011-04-17 04:08:48 +0000340 In the code, functions and variables are annotated with
Paul Gortmaker0db06282013-06-19 14:53:51 -0400341 __init,, etc. (see the full list in include/linux/init.h),
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100342 which results in the code/data being placed in specific sections.
Michael Wittene809ab02011-04-17 04:08:48 +0000343 The section mismatch analysis is always performed after a full
344 kernel build, and enabling this option causes the following
345 additional steps to occur:
346 - Add the option -fno-inline-functions-called-once to gcc commands.
347 When inlining a function annotated with __init in a non-init
348 function, we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100349 the analysis would not catch the illegal reference.
Michael Wittene809ab02011-04-17 04:08:48 +0000350 This option tells gcc to inline less (but it does result in
351 a larger kernel).
Nicholas Pigginf49821e2018-02-11 00:25:04 +1000352 - Run the section mismatch analysis for each module/built-in.a file.
Michael Wittene809ab02011-04-17 04:08:48 +0000353 When we run the section mismatch analysis on vmlinux.o, we
Uwe Kleine-König67797b92016-09-09 10:04:58 +0200354 lose valuable information about where the mismatch was
Sam Ravnborg91341d42008-01-21 21:31:44 +0100355 introduced.
Nicholas Pigginf49821e2018-02-11 00:25:04 +1000356 Running the analysis for each module/built-in.a file
Michael Wittene809ab02011-04-17 04:08:48 +0000357 tells where the mismatch happens much closer to the
358 source. The drawback is that the same mismatch is
359 reported at least twice.
360 - Enable verbose reporting from modpost in order to help resolve
361 the section mismatches that are reported.
Sam Ravnborg91341d42008-01-21 21:31:44 +0100362
Nicolas Boichat47490ec2015-10-06 09:44:42 +1030363config SECTION_MISMATCH_WARN_ONLY
364 bool "Make section mismatch errors non-fatal"
365 default y
366 help
367 If you say N here, the build process will fail if there are any
368 section mismatch, instead of just throwing warnings.
369
370 If unsure, say Y.
371
Dave Hansen6dfc0662013-07-01 13:04:46 -0700372#
373# Select this config option from the architecture Kconfig, if it
374# is preferred to always offer frame pointers as a config
375# option on the architecture (regardless of KERNEL_DEBUG):
376#
377config ARCH_WANT_FRAME_POINTERS
378 bool
Dave Hansen6dfc0662013-07-01 13:04:46 -0700379
380config FRAME_POINTER
381 bool "Compile the kernel with frame pointers"
Arnd Bergmanna687a532018-03-07 23:30:54 +0100382 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
Dave Hansen6dfc0662013-07-01 13:04:46 -0700383 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
384 help
385 If you say Y here the resulting kernel image will be slightly
386 larger and slower, but it gives very useful debugging information
387 in case of kernel bugs. (precise oopses/stacktraces/warnings)
388
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600389config STACK_VALIDATION
390 bool "Compile-time stack metadata validation"
391 depends on HAVE_STACK_VALIDATION
392 default n
393 help
394 Add compile-time checks to validate stack metadata, including frame
395 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
396 that runtime stack traces are more reliable.
397
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500398 This is also a prerequisite for generation of ORC unwind data, which
Josh Poimboeuf11af8472017-10-13 15:02:00 -0500399 is needed for CONFIG_UNWINDER_ORC.
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500400
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600401 For more information, see
402 tools/objtool/Documentation/stack-validation.txt.
403
Dave Hansen6dfc0662013-07-01 13:04:46 -0700404config DEBUG_FORCE_WEAK_PER_CPU
405 bool "Force weak per-cpu definitions"
406 depends on DEBUG_KERNEL
407 help
408 s390 and alpha require percpu variables in modules to be
409 defined weak to work around addressing range issue which
410 puts the following two restrictions on percpu variable
411 definitions.
412
413 1. percpu symbols must be unique whether static or not
414 2. percpu variables can't be defined inside a function
415
416 To ensure that generic code follows the above rules, this
417 option forces all percpu variables to be defined as weak.
418
419endmenu # "Compiler options"
420
421config MAGIC_SYSRQ
422 bool "Magic SysRq key"
423 depends on !UML
424 help
425 If you say Y here, you will have some control over the system even
426 if the system crashes for example during kernel debugging (e.g., you
427 will be able to flush the buffer cache to disk, reboot the system
428 immediately or dump some status information). This is accomplished
429 by pressing various keys while holding SysRq (Alt+PrintScreen). It
430 also works on a serial console (on PC hardware at least), if you
431 send a BREAK and then within 5 seconds a command keypress. The
Hans Holmbergf8998c22017-03-16 09:37:32 +0100432 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
433 Don't say Y unless you really know what this hack does.
Dave Hansen6dfc0662013-07-01 13:04:46 -0700434
Ben Hutchings8eaede42013-10-07 01:05:46 +0100435config MAGIC_SYSRQ_DEFAULT_ENABLE
436 hex "Enable magic SysRq key functions by default"
437 depends on MAGIC_SYSRQ
438 default 0x1
439 help
440 Specifies which SysRq key functions are enabled by default.
441 This may be set to 1 or 0 to enable or disable them all, or
Hans Holmbergf8998c22017-03-16 09:37:32 +0100442 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
Ben Hutchings8eaede42013-10-07 01:05:46 +0100443
Felix Fietkau732dbf32016-12-22 08:31:34 +0100444config MAGIC_SYSRQ_SERIAL
445 bool "Enable magic SysRq key over serial"
446 depends on MAGIC_SYSRQ
447 default y
448 help
449 Many embedded boards have a disconnected TTL level serial which can
450 generate some garbage that can lead to spurious false sysrq detects.
451 This option allows you to decide whether you want to enable the
452 magic SysRq key.
453
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800454config DEBUG_KERNEL
455 bool "Kernel debugging"
456 help
457 Say Y here if you are developing drivers or trying to debug and
458 identify kernel problems.
459
Dave Hansen0610c8a2013-07-01 13:04:43 -0700460menu "Memory Debugging"
David Woodhousea304e1b2007-02-12 00:52:00 -0800461
Dave Hansen0610c8a2013-07-01 13:04:43 -0700462source mm/Kconfig.debug
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800463
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700464config DEBUG_OBJECTS
465 bool "Debug object operations"
466 depends on DEBUG_KERNEL
467 help
468 If you say Y here, additional code will be inserted into the
469 kernel to track the life time of various objects and validate
470 the operations on those objects.
471
472config DEBUG_OBJECTS_SELFTEST
473 bool "Debug objects selftest"
474 depends on DEBUG_OBJECTS
475 help
476 This enables the selftest of the object debug code.
477
478config DEBUG_OBJECTS_FREE
479 bool "Debug objects in freed memory"
480 depends on DEBUG_OBJECTS
481 help
482 This enables checks whether a k/v free operation frees an area
483 which contains an object which has not been deactivated
484 properly. This can make kmalloc/kfree-intensive workloads
485 much slower.
486
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700487config DEBUG_OBJECTS_TIMERS
488 bool "Debug timer objects"
489 depends on DEBUG_OBJECTS
490 help
491 If you say Y here, additional code will be inserted into the
492 timer routines to track the life time of timer objects and
493 validate the timer operations.
494
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900495config DEBUG_OBJECTS_WORK
496 bool "Debug work objects"
497 depends on DEBUG_OBJECTS
498 help
499 If you say Y here, additional code will be inserted into the
500 work queue routines to track the life time of work objects and
501 validate the work operations.
502
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400503config DEBUG_OBJECTS_RCU_HEAD
504 bool "Debug RCU callbacks objects"
Mathieu Desnoyersfc2ecf72011-02-23 09:42:14 -0800505 depends on DEBUG_OBJECTS
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400506 help
507 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
508
Tejun Heoe2852ae2010-10-26 14:23:05 -0700509config DEBUG_OBJECTS_PERCPU_COUNTER
510 bool "Debug percpu counter objects"
511 depends on DEBUG_OBJECTS
512 help
513 If you say Y here, additional code will be inserted into the
514 percpu counter routines to track the life time of percpu counter
515 objects and validate the percpu counter operations.
516
Ingo Molnar3ae70202008-11-26 10:02:00 +0100517config DEBUG_OBJECTS_ENABLE_DEFAULT
518 int "debug_objects bootup default value (0-1)"
519 range 0 1
520 default "1"
521 depends on DEBUG_OBJECTS
522 help
523 Debug objects boot parameter default value
524
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800526 bool "Debug slab memory allocations"
Levin, Alexander (Sasha Levin)4675ff02017-11-15 17:36:02 -0800527 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 help
529 Say Y here to have the kernel do limited verification on memory
530 allocation as well as poisoning memory on free to catch use of freed
531 memory. This can make kmalloc/kfree-intensive workloads much slower.
532
Al Viro871751e2006-03-25 03:06:39 -0800533config DEBUG_SLAB_LEAK
534 bool "Memory leak debugging"
535 depends on DEBUG_SLAB
536
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700537config SLUB_DEBUG_ON
538 bool "SLUB debugging on by default"
Levin, Alexander (Sasha Levin)4675ff02017-11-15 17:36:02 -0800539 depends on SLUB && SLUB_DEBUG
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700540 default n
541 help
542 Boot with debugging on by default. SLUB boots by default with
543 the runtime debug capabilities switched off. Enabling this is
544 equivalent to specifying the "slub_debug" parameter on boot.
545 There is no support for more fine grained debug control like
546 possible with slub_debug=xxx. SLUB debugging may be switched
547 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
548 "slub_debug=-".
549
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800550config SLUB_STATS
551 default n
552 bool "Enable SLUB performance statistics"
Christoph Lameterab4d5ed2010-10-05 13:57:26 -0500553 depends on SLUB && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800554 help
555 SLUB statistics are useful to debug SLUBs allocation behavior in
556 order find ways to optimize the allocator. This should never be
557 enabled for production use since keeping statistics slows down
558 the allocator by a few percentage points. The slabinfo command
559 supports the determination of the most active slabs to figure
560 out which slabs are relevant to a particular load.
561 Try running: slabinfo -DA
562
Catalin Marinasb69ec422012-10-08 16:28:11 -0700563config HAVE_DEBUG_KMEMLEAK
564 bool
565
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100566config DEBUG_KMEMLEAK
567 bool "Kernel memory leak detector"
Kees Cook525c1f92013-01-16 18:54:16 -0800568 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
Catalin Marinas79e0d9b2011-04-27 17:06:19 +0100569 select DEBUG_FS
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100570 select STACKTRACE if STACKTRACE_SUPPORT
571 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800572 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100573 help
574 Say Y here if you want to enable the memory leak
575 detector. The memory allocation/freeing is traced in a way
576 similar to the Boehm's conservative garbage collector, the
577 difference being that the orphan objects are not freed but
578 only shown in /sys/kernel/debug/kmemleak. Enabling this
579 feature will introduce an overhead to memory
Andreas Platschek700199b02016-12-14 15:05:40 -0800580 allocations. See Documentation/dev-tools/kmemleak.rst for more
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100581 details.
582
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100583 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
584 of finding leaks due to the slab objects poisoning.
585
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100586 In order to access the kmemleak file, debugfs needs to be
587 mounted (usually at /sys/kernel/debug).
588
Catalin Marinasa9d90582009-06-25 10:16:11 +0100589config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
590 int "Maximum kmemleak early log entries"
591 depends on DEBUG_KMEMLEAK
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200592 range 200 40000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100593 default 400
594 help
595 Kmemleak must track all the memory allocations to avoid
596 reporting false positives. Since memory may be allocated or
597 freed before kmemleak is initialised, an early log buffer is
598 used to store these actions. If kmemleak reports "early log
599 buffer exceeded", please increase this value.
600
Catalin Marinas0822ee42009-06-11 13:24:14 +0100601config DEBUG_KMEMLEAK_TEST
602 tristate "Simple test for the kernel memory leak detector"
Daniel Baluta97182692011-04-04 15:06:44 -0700603 depends on DEBUG_KMEMLEAK && m
Catalin Marinas0822ee42009-06-11 13:24:14 +0100604 help
Daniel Baluta97182692011-04-04 15:06:44 -0700605 This option enables a module that explicitly leaks memory.
Catalin Marinas0822ee42009-06-11 13:24:14 +0100606
607 If unsure, say N.
608
Jason Baronab0155a2010-07-19 11:54:17 +0100609config DEBUG_KMEMLEAK_DEFAULT_OFF
610 bool "Default kmemleak to off"
611 depends on DEBUG_KMEMLEAK
612 help
613 Say Y here to disable kmemleak by default. It can then be enabled
614 on the command line via kmemleak=on.
615
Dave Hansen0610c8a2013-07-01 13:04:43 -0700616config DEBUG_STACK_USAGE
617 bool "Stack utilization instrumentation"
Helge Deller6c31da32016-03-19 17:54:10 +0100618 depends on DEBUG_KERNEL && !IA64
Dave Hansen0610c8a2013-07-01 13:04:43 -0700619 help
620 Enables the display of the minimum amount of free stack which each
621 task has ever had available in the sysrq-T and sysrq-P debug output.
622
623 This option will slow down process creation somewhat.
624
625config DEBUG_VM
626 bool "Debug VM"
627 depends on DEBUG_KERNEL
628 help
629 Enable this to turn on extended checks in the virtual-memory system
630 that may impact performance.
631
632 If unsure, say N.
633
Davidlohr Bueso4f115142014-06-04 16:06:46 -0700634config DEBUG_VM_VMACACHE
635 bool "Debug VMA caching"
636 depends on DEBUG_VM
637 help
638 Enable this to turn on VMA caching debug information. Doing so
639 can cause significant overhead, so only enable it in non-production
640 environments.
641
642 If unsure, say N.
643
Dave Hansen0610c8a2013-07-01 13:04:43 -0700644config DEBUG_VM_RB
645 bool "Debug VM red-black trees"
646 depends on DEBUG_VM
647 help
Davidlohr Buesoa663dad2014-04-18 15:07:22 -0700648 Enable VM red-black tree debugging information and extra validations.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700649
650 If unsure, say N.
651
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800652config DEBUG_VM_PGFLAGS
653 bool "Debug page-flags operations"
654 depends on DEBUG_VM
655 help
656 Enables extra validation on page flags operations.
657
658 If unsure, say N.
659
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800660config ARCH_HAS_DEBUG_VIRTUAL
661 bool
662
Dave Hansen0610c8a2013-07-01 13:04:43 -0700663config DEBUG_VIRTUAL
664 bool "Debug VM translations"
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800665 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
Dave Hansen0610c8a2013-07-01 13:04:43 -0700666 help
667 Enable some costly sanity checks in virtual to page code. This can
668 catch mistakes with virt_to_page() and friends.
669
670 If unsure, say N.
671
672config DEBUG_NOMMU_REGIONS
673 bool "Debug the global anon/private NOMMU mapping region tree"
674 depends on DEBUG_KERNEL && !MMU
675 help
676 This option causes the global tree of anonymous and private mapping
677 regions to be regularly checked for invalid topology.
678
679config DEBUG_MEMORY_INIT
680 bool "Debug memory initialisation" if EXPERT
681 default !EXPERT
682 help
683 Enable this for additional checks during memory initialisation.
684 The sanity checks verify aspects of the VM such as the memory model
685 and other information provided by the architecture. Verbose
686 information will be printed at KERN_DEBUG loglevel depending
687 on the mminit_loglevel= command-line option.
688
689 If unsure, say Y
690
691config MEMORY_NOTIFIER_ERROR_INJECT
692 tristate "Memory hotplug notifier error injection module"
693 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
694 help
695 This option provides the ability to inject artificial errors to
696 memory hotplug notifier chain callbacks. It is controlled through
697 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
698
699 If the notifier call chain should be failed with some events
700 notified, write the error code to "actions/<notifier event>/error".
701
702 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
703
704 # cd /sys/kernel/debug/notifier-error-inject/memory
705 # echo -12 > actions/MEM_GOING_OFFLINE/error
706 # echo offline > /sys/devices/system/memory/memoryXXX/state
707 bash: echo: write error: Cannot allocate memory
708
709 To compile this code as a module, choose M here: the module will
710 be called memory-notifier-error-inject.
711
712 If unsure, say N.
713
714config DEBUG_PER_CPU_MAPS
715 bool "Debug access to per_cpu maps"
716 depends on DEBUG_KERNEL
717 depends on SMP
718 help
719 Say Y to verify that the per_cpu map being accessed has
720 been set up. This adds a fair amount of code to kernel memory
721 and decreases performance.
722
723 Say N if unsure.
724
725config DEBUG_HIGHMEM
726 bool "Highmem debugging"
727 depends on DEBUG_KERNEL && HIGHMEM
728 help
Geert Uytterhoevenb1357c92014-04-14 18:55:50 +0200729 This option enables additional error checking for high memory
730 systems. Disable for production systems.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700731
732config HAVE_DEBUG_STACKOVERFLOW
733 bool
734
735config DEBUG_STACKOVERFLOW
736 bool "Check for stack overflows"
737 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
738 ---help---
739 Say Y here if you want to check for overflows of kernel, IRQ
Borislav Petkovedb0ec02015-01-25 19:50:34 +0100740 and exception stacks (if your architecture uses them). This
Dave Hansen0610c8a2013-07-01 13:04:43 -0700741 option will show detailed messages if free stack space drops
742 below a certain limit.
743
744 These kinds of bugs usually occur when call-chains in the
745 kernel get too deep, especially when interrupts are
746 involved.
747
748 Use this in cases where you see apparently random memory
749 corruption, especially if it appears in 'struct thread_info'
750
751 If in doubt, say "N".
752
Andrey Ryabinin0b24bec2015-02-13 14:39:17 -0800753source "lib/Kconfig.kasan"
754
Dave Hansen0610c8a2013-07-01 13:04:43 -0700755endmenu # "Memory Debugging"
756
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700757config ARCH_HAS_KCOV
758 bool
759 help
760 KCOV does not have any arch-specific code, but currently it is enabled
761 only for x86_64. KCOV requires testing on other archs, and most likely
762 disabling of instrumentation for some early boot code.
763
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900764config CC_HAS_SANCOV_TRACE_PC
765 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
766
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700767config KCOV
768 bool "Code coverage for fuzzing"
769 depends on ARCH_HAS_KCOV
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900770 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700771 select DEBUG_FS
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900772 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700773 help
774 KCOV exposes kernel code coverage information in a form suitable
775 for coverage-guided fuzzing (randomized testing).
776
777 If RANDOMIZE_BASE is enabled, PC values will not be stable across
778 different machines and across reboots. If you need stable PC values,
779 disable RANDOMIZE_BASE.
780
Andreas Platschek700199b02016-12-14 15:05:40 -0800781 For more details, see Documentation/dev-tools/kcov.rst.
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700782
Victor Chibotarud677a4d2017-11-17 15:30:50 -0800783config KCOV_ENABLE_COMPARISONS
784 bool "Enable comparison operands collection by KCOV"
785 depends on KCOV
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900786 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
Victor Chibotarud677a4d2017-11-17 15:30:50 -0800787 help
788 KCOV also exposes operands of every comparison in the instrumented
789 code along with operand sizes and PCs of the comparison instructions.
790 These operands can be used by fuzzing engines to improve the quality
791 of fuzzing coverage.
792
Vegard Nossuma4691de2016-08-02 14:07:30 -0700793config KCOV_INSTRUMENT_ALL
794 bool "Instrument all code by default"
795 depends on KCOV
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900796 default y
Vegard Nossuma4691de2016-08-02 14:07:30 -0700797 help
798 If you are doing generic system call fuzzing (like e.g. syzkaller),
799 then you will want to instrument the whole kernel and you should
800 say y here. If you are doing more targeted fuzzing (like e.g.
801 filesystem fuzzing with AFL) then you will want to enable coverage
802 for more specific subsets of files, and should say n here.
803
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804config DEBUG_SHIRQ
805 bool "Debug shared IRQ handlers"
Martin Schwidefsky0244ad02013-08-30 09:39:53 +0200806 depends on DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807 help
808 Enable this to generate a spurious interrupt as soon as a shared
809 interrupt handler is registered, and just before one is deregistered.
810 Drivers ought to be able to handle interrupts coming in at those
811 points; some don't and need to be caught.
812
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700813menu "Debug Lockups and Hangs"
814
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815config LOCKUP_DETECTOR
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700816 bool
817
818config SOFTLOCKUP_DETECTOR
819 bool "Detect Soft Lockups"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 depends on DEBUG_KERNEL && !S390
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700821 select LOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 help
823 Say Y here to enable the kernel to act as a watchdog to detect
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700824 soft lockups.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825
826 Softlockups are bugs that cause the kernel to loop in kernel
827 mode for more than 20 seconds, without giving other tasks a
828 chance to run. The current stack trace is displayed upon
829 detection and the system will stay locked up.
830
Randy Dunlap5f00ae02018-04-10 16:32:51 -0700831config BOOTPARAM_SOFTLOCKUP_PANIC
832 bool "Panic (Reboot) On Soft Lockups"
833 depends on SOFTLOCKUP_DETECTOR
834 help
835 Say Y here to enable the kernel to panic on "soft lockups",
836 which are bugs that cause the kernel to loop in kernel
837 mode for more than 20 seconds (configurable using the watchdog_thresh
838 sysctl), without giving other tasks a chance to run.
839
840 The panic can be used in combination with panic_timeout,
841 to cause the system to reboot automatically after a
842 lockup has been detected. This feature is useful for
843 high-availability systems that have uptime guarantees and
844 where a lockup must be resolved ASAP.
845
846 Say N if unsure.
847
848config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
849 int
850 depends on SOFTLOCKUP_DETECTOR
851 range 0 1
852 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
853 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
854
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700855config HARDLOCKUP_DETECTOR_PERF
856 bool
857 select SOFTLOCKUP_DETECTOR
858
859#
Thomas Gleixner7edaeb62017-08-15 09:50:13 +0200860# Enables a timestamp based low pass filter to compensate for perf based
861# hard lockup detection which runs too fast due to turbo modes.
862#
863config HARDLOCKUP_CHECK_TIMESTAMP
864 bool
865
866#
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700867# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
868# lockup detector rather than the perf based detector.
869#
870config HARDLOCKUP_DETECTOR
871 bool "Detect Hard Lockups"
872 depends on DEBUG_KERNEL && !S390
873 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
874 select LOCKUP_DETECTOR
875 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
876 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
877 help
878 Say Y here to enable the kernel to act as a watchdog to detect
879 hard lockups.
880
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 Hardlockups are bugs that cause the CPU to loop in kernel mode
882 for more than 10 seconds, without letting other interrupts have a
883 chance to run. The current stack trace is displayed upon detection
884 and the system will stay locked up.
885
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886config BOOTPARAM_HARDLOCKUP_PANIC
887 bool "Panic (Reboot) On Hard Lockups"
888 depends on HARDLOCKUP_DETECTOR
889 help
890 Say Y here to enable the kernel to panic on "hard lockups",
891 which are bugs that cause the kernel to loop in kernel
892 mode with interrupts disabled for more than 10 seconds (configurable
893 using the watchdog_thresh sysctl).
894
895 Say N if unsure.
896
897config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
898 int
899 depends on HARDLOCKUP_DETECTOR
900 range 0 1
901 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
902 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
903
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904config DETECT_HUNG_TASK
905 bool "Detect Hung Tasks"
906 depends on DEBUG_KERNEL
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700907 default SOFTLOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908 help
909 Say Y here to enable the kernel to detect "hung tasks",
910 which are bugs that cause the task to be stuck in
Vivien Didelot96b03ab2016-09-22 16:55:13 -0400911 uninterruptible "D" state indefinitely.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912
913 When a hung task is detected, the kernel will print the
914 current stack trace (which you should report), but the
915 task will stay in uninterruptible state. If lockdep is
916 enabled then all held locks will also be reported. This
917 feature has negligible overhead.
918
919config DEFAULT_HUNG_TASK_TIMEOUT
920 int "Default timeout for hung task detection (in seconds)"
921 depends on DETECT_HUNG_TASK
922 default 120
923 help
Ingo Molnar8637c092006-07-03 00:24:38 -0700924 This option controls the default timeout (in seconds) used
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925 to determine when a task has become non-responsive and should
926 be considered hung.
927
928 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
929 sysctl or by writing a value to
930 /proc/sys/kernel/hung_task_timeout_secs.
931
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700932 A timeout of 0 disables the check. The default is two minutes.
933 Keeping the default should be fine in most cases.
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700934
935config BOOTPARAM_HUNG_TASK_PANIC
936 bool "Panic (Reboot) On Hung Tasks"
937 depends on DETECT_HUNG_TASK
938 help
939 Say Y here to enable the kernel to panic on "hung tasks",
940 which are bugs that cause the kernel to leave a task stuck
941 in uninterruptible "D" state.
942
943 The panic can be used in combination with panic_timeout,
Thomas Gleixner61a87122006-06-27 02:54:56 -0700944 to cause the system to reboot automatically after a
945 hung task has been detected. This feature is useful for
Roman Zippela1583d32006-06-27 02:55:00 -0700946 high-availability systems that have uptime guarantees and
Thomas Gleixner61a87122006-06-27 02:54:56 -0700947 where a hung tasks must be resolved ASAP.
948
949 Say N if unsure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100951config BOOTPARAM_HUNG_TASK_PANIC_VALUE
Linus Torvalds1da177e2005-04-16 15:20:36 -0700952 int
953 depends on DETECT_HUNG_TASK
954 range 0 1
955 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
956 default 1 if BOOTPARAM_HUNG_TASK_PANIC
957
Tejun Heo82607adc2015-12-08 11:28:04 -0500958config WQ_WATCHDOG
959 bool "Detect Workqueue Stalls"
960 depends on DEBUG_KERNEL
961 help
962 Say Y here to enable stall detection on workqueues. If a
963 worker pool doesn't make forward progress on a pending work
964 item for over a given amount of time, 30s by default, a
965 warning message is printed along with dump of workqueue
966 state. This can be configured through kernel parameter
967 "workqueue.watchdog_thresh" and its sysfs counterpart.
968
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700969endmenu # "Debug lockups and hangs"
970
971config PANIC_ON_OOPS
972 bool "Panic on Oops"
973 help
974 Say Y here to enable the kernel to panic when it oopses. This
975 has the same effect as setting oops=panic on the kernel command
976 line.
977
978 This feature is useful to ensure that the kernel does not do
979 anything erroneous after an oops which could result in data
980 corruption or other issues.
981
982 Say N if unsure.
983
984config PANIC_ON_OOPS_VALUE
985 int
986 range 0 1
987 default 0 if !PANIC_ON_OOPS
988 default 1 if PANIC_ON_OOPS
989
Jason Baron5800dc32013-11-25 23:23:04 +0000990config PANIC_TIMEOUT
991 int "panic timeout"
992 default 0
993 help
994 Set the timeout value (in seconds) until a reboot occurs when the
995 the kernel panics. If n = 0, then we wait forever. A timeout
996 value n > 0 will wait n seconds before rebooting, while a timeout
997 value n < 0 will reboot immediately.
998
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999config SCHED_DEBUG
1000 bool "Collect scheduler debugging info"
1001 depends on DEBUG_KERNEL && PROC_FS
1002 default y
1003 help
1004 If you say Y here, the /proc/sched_debug file will be provided
1005 that can help debug the scheduler. The runtime overhead of this
1006 option is minimal.
1007
Naveen N. Raof6db8342015-06-25 23:53:37 +05301008config SCHED_INFO
1009 bool
1010 default n
1011
Satya Durga Srinivasu Prabhala1ff44892018-01-31 14:38:24 -08001012config PANIC_ON_SCHED_BUG
1013 bool "Panic on all bugs encountered by the scheduler"
1014 help
1015 Say Y here to panic on all 'BUG:' conditions encountered by the
1016 scheduler, even potentially-recoverable ones such as scheduling
1017 while atomic, sleeping from invalid context, and detection of
1018 broken arch topologies.
1019
1020 Say N if unsure.
1021
Satya Durga Srinivasu Prabhala727342a2018-11-16 16:05:52 -08001022config PANIC_ON_RT_THROTTLING
1023 bool "Panic on RT throttling"
1024 help
1025 Say Y here to enable the kernel to panic when a realtime
1026 runqueue is throttled. This may be useful for detecting
1027 and debugging RT throttling issues.
1028
1029 Say N if unsure.
1030
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031config SCHEDSTATS
1032 bool "Collect scheduler statistics"
1033 depends on DEBUG_KERNEL && PROC_FS
Naveen N. Raof6db8342015-06-25 23:53:37 +05301034 select SCHED_INFO
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035 help
1036 If you say Y here, additional code will be inserted into the
1037 scheduler and related routines to collect statistics about
1038 scheduler behavior and provide them in /proc/schedstat. These
1039 stats may be useful for both tuning and debugging the scheduler
1040 If you aren't debugging the scheduler or trying to tune a specific
1041 application, you can say N to avoid the very slight overhead
1042 this adds.
1043
Aaron Tomlin0d9e2632014-09-12 14:16:19 +01001044config SCHED_STACK_END_CHECK
1045 bool "Detect stack corruption on calls to schedule()"
1046 depends on DEBUG_KERNEL
1047 default n
1048 help
1049 This option checks for a stack overrun on calls to schedule().
1050 If the stack end location is found to be over written always panic as
1051 the content of the corrupted region can no longer be trusted.
1052 This is to ensure no erroneous behaviour occurs which could result in
1053 data corruption or a sporadic crash at a later stage once the region
1054 is examined. The runtime overhead introduced is minimal.
1055
John Stultz3c17ad12015-03-11 21:16:32 -07001056config DEBUG_TIMEKEEPING
1057 bool "Enable extra timekeeping sanity checking"
1058 help
1059 This option will enable additional timekeeping sanity checks
1060 which may be helpful when diagnosing issues where timekeeping
1061 problems are suspected.
1062
1063 This may include checks in the timekeeping hotpaths, so this
1064 option may have a (very small) performance impact to some
1065 workloads.
1066
1067 If unsure, say N.
1068
Vignesh Radhakrishnan2ac0a4e2015-01-22 11:43:45 +05301069config DEBUG_TASK_STACK_SCAN_OFF
1070 bool "Disable kmemleak task stack scan by default"
1071 depends on DEBUG_KMEMLEAK
1072 help
1073 Say Y here to disable kmemleak task stack scan by default
1074 at compile time. It can be enabled later if required by
1075 writing to the debugfs entry :
1076 echo "stack=on" > /sys/kernel/debug/kmemleak.
1077
Linus Torvalds1da177e2005-04-16 15:20:36 -07001078config DEBUG_PREEMPT
1079 bool "Debug preemptible kernel"
Kumar Gala01deab92009-10-16 07:21:39 +00001080 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081 default y
1082 help
1083 If you say Y here then the kernel will use a debug variant of the
1084 commonly used smp_processor_id() function and will print warnings
1085 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1086 will detect preemption count underflows.
1087
Dave Hansen9eade162013-07-01 13:04:47 -07001088menu "Lock Debugging (spinlocks, mutexes, etc...)"
1089
Waiman Longf07cbeb2018-03-30 17:27:59 -04001090config LOCK_DEBUGGING_SUPPORT
1091 bool
1092 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1093 default y
1094
Rohit Vaswanie0965e62014-10-02 21:02:56 -07001095choice
1096 prompt "Perform Action on spinlock bug"
1097 depends on DEBUG_SPINLOCK
1098
1099 default DEBUG_SPINLOCK_BITE_ON_BUG
1100
1101 config DEBUG_SPINLOCK_BITE_ON_BUG
1102 bool "Cause a Watchdog Bite on Spinlock bug"
1103 depends on QCOM_WATCHDOG_V2
1104 help
1105 On a spinlock bug, cause a watchdog bite so that we can get
1106 the precise state of the system captured at the time of spin
1107 dump. This is mutually exclusive with the below
1108 DEBUG_SPINLOCK_PANIC_ON_BUG config.
1109
1110 config DEBUG_SPINLOCK_PANIC_ON_BUG
1111 bool "Cause a Kernel Panic on Spinlock bug"
1112 help
1113 On a spinlock bug, cause a kernel panic so that we can get the complete
1114 information about the system at the time of spin dump in the dmesg.
1115 This is mutually exclusive with the above DEBUG_SPINLOCK_BITE_ON_BUG.
1116endchoice
1117
Waiman Long19193bc2018-03-30 17:28:00 -04001118config PROVE_LOCKING
1119 bool "Lock debugging: prove locking correctness"
1120 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1121 select LOCKDEP
1122 select DEBUG_SPINLOCK
1123 select DEBUG_MUTEXES
1124 select DEBUG_RT_MUTEXES if RT_MUTEXES
1125 select DEBUG_RWSEMS if RWSEM_SPIN_ON_OWNER
Lakshmi Narayana Kalavala4137ad72019-04-11 14:28:40 -07001126 select DEBUG_WW_MUTEX_SLOWPATH
Waiman Long19193bc2018-03-30 17:28:00 -04001127 select DEBUG_LOCK_ALLOC
1128 select TRACE_IRQFLAGS
1129 default n
1130 help
1131 This feature enables the kernel to prove that all locking
1132 that occurs in the kernel runtime is mathematically
1133 correct: that under no circumstance could an arbitrary (and
1134 not yet triggered) combination of observed locking
1135 sequences (on an arbitrary number of CPUs, running an
1136 arbitrary number of tasks and interrupt contexts) cause a
1137 deadlock.
1138
1139 In short, this feature enables the kernel to report locking
1140 related deadlocks before they actually occur.
1141
1142 The proof does not depend on how hard and complex a
1143 deadlock scenario would be to trigger: how many
1144 participant CPUs, tasks and irq-contexts would be needed
1145 for it to trigger. The proof also does not depend on
1146 timing: if a race and a resulting deadlock is possible
1147 theoretically (no matter how unlikely the race scenario
1148 is), it will be proven so and will immediately be
1149 reported by the kernel (once the event is observed that
1150 makes the deadlock theoretically possible).
1151
1152 If a deadlock is impossible (i.e. the locking rules, as
1153 observed by the kernel, are mathematically correct), the
1154 kernel reports nothing.
1155
1156 NOTE: this feature can also be enabled for rwlocks, mutexes
1157 and rwsems - in which case all dependencies between these
1158 different locking variants are observed and mapped too, and
1159 the proof of observed correctness is also maintained for an
1160 arbitrary combination of these separate locking variants.
1161
1162 For more details, see Documentation/locking/lockdep-design.txt.
1163
1164config LOCK_STAT
1165 bool "Lock usage statistics"
1166 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1167 select LOCKDEP
1168 select DEBUG_SPINLOCK
1169 select DEBUG_MUTEXES
1170 select DEBUG_RT_MUTEXES if RT_MUTEXES
1171 select DEBUG_LOCK_ALLOC
1172 default n
1173 help
1174 This feature enables tracking lock contention points
1175
1176 For more details, see Documentation/locking/lockstat.txt
1177
1178 This also enables lock events required by "perf lock",
1179 subcommand of perf.
1180 If you want to use "perf lock", you also need to turn on
1181 CONFIG_EVENT_TRACING.
1182
1183 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1184 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1185
Linus Torvalds1da177e2005-04-16 15:20:36 -07001186config DEBUG_RT_MUTEXES
1187 bool "RT Mutex debugging, deadlock detection"
1188 depends on DEBUG_KERNEL && RT_MUTEXES
1189 help
1190 This allows rt mutex semantics violations and rt mutex related
1191 deadlocks (lockups) to be detected and reported automatically.
1192
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001194 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +05301196 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197 help
1198 Say Y here and build SMP to catch missing spinlock initialization
1199 and certain other kinds of spinlock errors commonly made. This is
1200 best used in conjunction with the NMI watchdog so that spinlock
1201 deadlocks are also debuggable.
1202
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001203config DEBUG_MUTEXES
1204 bool "Mutex debugging: basic checks"
1205 depends on DEBUG_KERNEL
1206 help
1207 This feature allows mutex semantics violations to be detected and
1208 reported.
1209
Daniel Vetter23010022013-06-20 13:31:17 +02001210config DEBUG_WW_MUTEX_SLOWPATH
1211 bool "Wait/wound mutex debugging: Slowpath testing"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001212 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Daniel Vetter23010022013-06-20 13:31:17 +02001213 select DEBUG_LOCK_ALLOC
1214 select DEBUG_SPINLOCK
1215 select DEBUG_MUTEXES
1216 help
1217 This feature enables slowpath testing for w/w mutex users by
1218 injecting additional -EDEADLK wound/backoff cases. Together with
1219 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1220 will test all possible w/w mutex interface abuse with the
1221 exception of simply not acquiring all the required locks.
Rob Clark4d692372014-08-27 11:19:26 -04001222 Note that this feature can introduce significant overhead, so
1223 it really should not be enabled in a production or distro kernel,
1224 even a debug kernel. If you are a driver writer, enable it. If
1225 you are a distro, do not.
Daniel Vetter23010022013-06-20 13:31:17 +02001226
Waiman Long5149cba2018-03-30 17:27:58 -04001227config DEBUG_RWSEMS
1228 bool "RW Semaphore debugging: basic checks"
1229 depends on DEBUG_KERNEL && RWSEM_SPIN_ON_OWNER
1230 help
1231 This debugging feature allows mismatched rw semaphore locks and unlocks
1232 to be detected and reported.
1233
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001234config DEBUG_LOCK_ALLOC
1235 bool "Lock debugging: detect incorrect freeing of live locks"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001236 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001237 select DEBUG_SPINLOCK
1238 select DEBUG_MUTEXES
Peter Zijlstraf5694782016-09-19 12:15:37 +02001239 select DEBUG_RT_MUTEXES if RT_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001240 select LOCKDEP
1241 help
1242 This feature will check whether any held lock (spinlock, rwlock,
1243 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1244 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1245 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1246 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1247 held during task exit.
1248
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001249config LOCKDEP
1250 bool
Waiman Longf07cbeb2018-03-30 17:27:59 -04001251 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001252 select STACKTRACE
Linus Torvaldsf5a8eb62018-04-02 20:20:12 -07001253 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC && !X86
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001254 select KALLSYMS
1255 select KALLSYMS_ALL
1256
Daniel Jordan395102d2017-04-10 11:50:52 -04001257config LOCKDEP_SMALL
1258 bool
1259
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001260config DEBUG_LOCKDEP
1261 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -07001262 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001263 help
1264 If you say Y here, the lock dependency engine will do
1265 additional runtime checks to debug itself, at the price
1266 of more runtime overhead.
1267
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001268config DEBUG_ATOMIC_SLEEP
1269 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +02001270 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 depends on DEBUG_KERNEL
Christoph Hellwig87a4c372018-07-31 13:39:32 +02001272 depends on !ARCH_NO_PREEMPT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273 help
1274 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001275 noisy if they are called inside atomic sections: when a spinlock is
1276 held, inside an rcu read side critical section, inside preempt disabled
1277 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278
Ingo Molnarcae2ed92006-07-03 00:24:48 -07001279config DEBUG_LOCKING_API_SELFTESTS
1280 bool "Locking API boot-time self-tests"
1281 depends on DEBUG_KERNEL
1282 help
1283 Say Y here if you want the kernel to run a short self-test during
1284 bootup. The self-test checks whether common types of locking bugs
1285 are detected by debugging mechanisms or not. (if you disable
1286 lock debugging then those bugs wont be detected of course.)
1287 The following locking APIs are covered: spinlocks, rwlocks,
1288 mutexes and rwsems.
1289
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001290config LOCK_TORTURE_TEST
1291 tristate "torture tests for locking"
1292 depends on DEBUG_KERNEL
1293 select TORTURE_TEST
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001294 help
1295 This option provides a kernel module that runs torture tests
1296 on kernel locking primitives. The kernel module may be built
1297 after the fact on the running kernel to be tested, if desired.
1298
1299 Say Y here if you want kernel locking-primitive torture tests
1300 to be built into the kernel.
1301 Say M if you want these torture tests to build as a module.
1302 Say N if you are unsure.
1303
Chris Wilsonf2a5fec2016-12-01 11:47:06 +00001304config WW_MUTEX_SELFTEST
1305 tristate "Wait/wound mutex selftests"
1306 help
1307 This option provides a kernel module that runs tests on the
1308 on the struct ww_mutex locking API.
1309
1310 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1311 with this test harness.
1312
1313 Say M if you want these self tests to build as a module.
1314 Say N if you are unsure.
1315
Dave Hansen9eade162013-07-01 13:04:47 -07001316endmenu # lock debugging
1317
1318config TRACE_IRQFLAGS
1319 bool
1320 help
1321 Enables hooks to interrupt enabling and disabling for
1322 either tracing or lock debugging.
1323
Ingo Molnar8637c092006-07-03 00:24:38 -07001324config STACKTRACE
Dave Jones0c38e1f2014-08-29 15:18:35 -07001325 bool "Stack backtrace support"
Ingo Molnar8637c092006-07-03 00:24:38 -07001326 depends on STACKTRACE_SUPPORT
Dave Jones0c38e1f2014-08-29 15:18:35 -07001327 help
1328 This option causes the kernel to create a /proc/pid/stack for
1329 every process, showing its current stack trace.
1330 It is also used by various kernel debugging features that require
1331 stack trace generation.
Ingo Molnar8637c092006-07-03 00:24:38 -07001332
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001333config WARN_ALL_UNSEEDED_RANDOM
1334 bool "Warn for all uses of unseeded randomness"
1335 default n
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001336 help
1337 Some parts of the kernel contain bugs relating to their use of
1338 cryptographically secure random numbers before it's actually possible
1339 to generate those numbers securely. This setting ensures that these
1340 flaws don't go unnoticed, by enabling a message, should this ever
1341 occur. This will allow people with obscure setups to know when things
1342 are going wrong, so that they might contact developers about fixing
1343 it.
1344
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001345 Unfortunately, on some models of some architectures getting
1346 a fully seeded CRNG is extremely difficult, and so this can
1347 result in dmesg getting spammed for a surprisingly long
1348 time. This is really bad from a security perspective, and
1349 so architecture maintainers really need to do what they can
1350 to get the CRNG seeded sooner after the system is booted.
Thibaut Sautereau4c5d1142018-09-04 15:46:23 -07001351 However, since users cannot do anything actionable to
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001352 address this, by default the kernel will issue only a single
1353 warning for the first use of unseeded randomness.
1354
1355 Say Y here if you want to receive warnings for all uses of
1356 unseeded randomness. This will be of use primarily for
Thibaut Sautereau4c5d1142018-09-04 15:46:23 -07001357 those developers interested in improving the security of
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001358 Linux kernels running on their architecture (or
1359 subarchitecture).
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001360
Linus Torvalds1da177e2005-04-16 15:20:36 -07001361config DEBUG_KOBJECT
1362 bool "kobject debugging"
1363 depends on DEBUG_KERNEL
1364 help
1365 If you say Y here, some extra kobject debugging messages will be sent
1366 to the syslog.
1367
Russell Kingc817a672013-06-27 15:06:14 +01001368config DEBUG_KOBJECT_RELEASE
1369 bool "kobject release debugging"
Linus Torvalds2a999aa2013-10-29 08:33:36 -07001370 depends on DEBUG_OBJECTS_TIMERS
Russell Kingc817a672013-06-27 15:06:14 +01001371 help
1372 kobjects are reference counted objects. This means that their
1373 last reference count put is not predictable, and the kobject can
1374 live on past the point at which a driver decides to drop it's
1375 initial reference to the kobject gained on allocation. An
1376 example of this would be a struct device which has just been
1377 unregistered.
1378
1379 However, some buggy drivers assume that after such an operation,
1380 the memory backing the kobject can be immediately freed. This
1381 goes completely against the principles of a refcounted object.
1382
1383 If you say Y here, the kernel will delay the release of kobjects
1384 on the last reference count to improve the visibility of this
1385 kind of kobject release bug.
1386
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001387config HAVE_DEBUG_BUGVERBOSE
1388 bool
1389
Linus Torvalds1da177e2005-04-16 15:20:36 -07001390config DEBUG_BUGVERBOSE
David Rientjes6a108a12011-01-20 14:44:16 -08001391 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001392 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
Alexey Dobriyan8420e7e2009-12-14 18:00:25 -08001393 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394 help
1395 Say Y here to make BUG() panics output the file name and line number
1396 of the BUG call as well as the EIP and oops trace. This aids
1397 debugging but costs about 70-100K of memory.
1398
Dave Jones199a9af2006-09-29 01:59:00 -07001399config DEBUG_LIST
1400 bool "Debug linked list manipulation"
Arnd Bergmann4520bcb2016-08-26 17:42:00 +02001401 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
Dave Jones199a9af2006-09-29 01:59:00 -07001402 help
1403 Enable this to turn on extended checks in the linked-list
1404 walking routines.
1405
1406 If unsure, say N.
1407
Dan Streetmanb8cfff62014-06-04 16:11:54 -07001408config DEBUG_PI_LIST
1409 bool "Debug priority linked list manipulation"
1410 depends on DEBUG_KERNEL
1411 help
1412 Enable this to turn on extended checks in the priority-ordered
1413 linked-list (plist) walking routines. This checks the entire
1414 list multiple times during each manipulation.
1415
1416 If unsure, say N.
1417
Jens Axboed6ec0842007-10-22 20:01:06 +02001418config DEBUG_SG
1419 bool "Debug SG table operations"
1420 depends on DEBUG_KERNEL
1421 help
1422 Enable this to turn on checks on scatter-gather tables. This can
1423 help find problems with drivers that do not properly initialize
1424 their sg tables.
1425
1426 If unsure, say N.
1427
Arjan van de Ven1b2439d2008-08-15 15:29:38 -07001428config DEBUG_NOTIFIERS
1429 bool "Debug notifier call chains"
1430 depends on DEBUG_KERNEL
1431 help
1432 Enable this to turn on sanity checking for notifier call chains.
1433 This is most useful for kernel developers to make sure that
1434 modules properly unregister themselves from notifier chains.
1435 This is a relatively cheap check but if you care about maximum
1436 performance, say N.
1437
David Howellse0e81732009-09-02 09:13:40 +01001438config DEBUG_CREDENTIALS
1439 bool "Debug credential management"
1440 depends on DEBUG_KERNEL
1441 help
1442 Enable this to turn on some debug checking for credential
1443 management. The additional code keeps track of the number of
1444 pointers from task_structs to any given cred struct, and checks to
1445 see that this number never exceeds the usage count of the cred
1446 struct.
1447
1448 Furthermore, if SELinux is enabled, this also checks that the
1449 security pointer in the cred struct is never seen to be invalid.
1450
1451 If unsure, say N.
1452
Paul E. McKenney43a0a2a2017-05-17 09:19:44 -07001453source "kernel/rcu/Kconfig.debug"
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001454
Tejun Heof303fcc2016-02-09 17:59:38 -05001455config DEBUG_WQ_FORCE_RR_CPU
1456 bool "Force round-robin CPU selection for unbound work items"
1457 depends on DEBUG_KERNEL
1458 default n
1459 help
1460 Workqueue used to implicitly guarantee that work items queued
1461 without explicit CPU specified are put on the local CPU. This
1462 guarantee is no longer true and while local CPU is still
1463 preferred work items may be put on foreign CPUs. Kernel
1464 parameter "workqueue.debug_force_rr_cpu" is added to force
1465 round-robin CPU selection to flush out usages which depend on the
1466 now broken guarantee. This config option enables the debug
1467 feature by default. When enabled, memory and cache locality will
1468 be impacted.
1469
Tejun Heo870d6652008-08-25 19:47:25 +09001470config DEBUG_BLOCK_EXT_DEVT
1471 bool "Force extended block device numbers and spread them"
1472 depends on DEBUG_KERNEL
1473 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +02001474 default n
Tejun Heo870d6652008-08-25 19:47:25 +09001475 help
Tejun Heo0e11e342008-10-13 10:46:01 +02001476 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1477 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1478 YOU ARE DOING. Distros, please enable this and fix whatever
1479 is broken.
1480
Tejun Heo870d6652008-08-25 19:47:25 +09001481 Conventionally, block device numbers are allocated from
1482 predetermined contiguous area. However, extended block area
1483 may introduce non-contiguous block device numbers. This
1484 option forces most block device numbers to be allocated from
1485 the extended space and spreads them to discover kernel or
1486 userland code paths which assume predetermined contiguous
1487 device number allocation.
1488
Tejun Heo55dc7db2008-09-01 13:44:35 +02001489 Note that turning on this debug option shuffles all the
1490 device numbers for all IDE and SCSI devices including libata
1491 ones, so root partition specified using device number
1492 directly (via rdev or root=MAJ:MIN) won't work anymore.
1493 Textual device names (root=/dev/sdXn) will continue to work.
1494
Tejun Heo870d6652008-08-25 19:47:25 +09001495 Say N if you are unsure.
1496
Thomas Gleixner757c9892016-02-26 18:43:32 +00001497config CPU_HOTPLUG_STATE_CONTROL
1498 bool "Enable CPU hotplug state control"
1499 depends on DEBUG_KERNEL
1500 depends on HOTPLUG_CPU
1501 default n
1502 help
1503 Allows to write steps between "offline" and "online" to the CPUs
1504 sysfs target file so states can be stepped granular. This is a debug
1505 option for now as the hotplug machinery cannot be stopped and
1506 restarted at arbitrary points yet.
1507
1508 Say N if your are unsure.
1509
Akinobu Mita8d438282012-07-30 14:43:02 -07001510config NOTIFIER_ERROR_INJECTION
1511 tristate "Notifier error injection"
1512 depends on DEBUG_KERNEL
1513 select DEBUG_FS
1514 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001515 This option provides the ability to inject artificial errors to
Akinobu Mita8d438282012-07-30 14:43:02 -07001516 specified notifier chain callbacks. It is useful to test the error
1517 handling of notifier call chain failures.
1518
1519 Say N if unsure.
1520
Akinobu Mita048b9c32012-07-30 14:43:07 -07001521config PM_NOTIFIER_ERROR_INJECT
1522 tristate "PM notifier error injection module"
1523 depends on PM && NOTIFIER_ERROR_INJECTION
1524 default m if PM_DEBUG
1525 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001526 This option provides the ability to inject artificial errors to
Akinobu Mita048b9c32012-07-30 14:43:07 -07001527 PM notifier chain callbacks. It is controlled through debugfs
1528 interface /sys/kernel/debug/notifier-error-inject/pm
1529
1530 If the notifier call chain should be failed with some events
1531 notified, write the error code to "actions/<notifier event>/error".
1532
1533 Example: Inject PM suspend error (-12 = -ENOMEM)
1534
1535 # cd /sys/kernel/debug/notifier-error-inject/pm/
1536 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1537 # echo mem > /sys/power/state
1538 bash: echo: write error: Cannot allocate memory
1539
1540 To compile this code as a module, choose M here: the module will
1541 be called pm-notifier-error-inject.
1542
1543 If unsure, say N.
1544
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001545config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1546 tristate "OF reconfig notifier error injection module"
1547 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001548 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001549 This option provides the ability to inject artificial errors to
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001550 OF reconfig notifier chain callbacks. It is controlled
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001551 through debugfs interface under
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001552 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001553
1554 If the notifier call chain should be failed with some events
1555 notified, write the error code to "actions/<notifier event>/error".
1556
1557 To compile this code as a module, choose M here: the module will
Akinobu Mitae12a95f2013-04-30 15:28:49 -07001558 be called of-reconfig-notifier-error-inject.
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001559
1560 If unsure, say N.
1561
Nikolay Aleksandrov02fff962015-11-28 13:45:28 +01001562config NETDEV_NOTIFIER_ERROR_INJECT
1563 tristate "Netdev notifier error injection module"
1564 depends on NET && NOTIFIER_ERROR_INJECTION
1565 help
1566 This option provides the ability to inject artificial errors to
1567 netdevice notifier chain callbacks. It is controlled through debugfs
1568 interface /sys/kernel/debug/notifier-error-inject/netdev
1569
1570 If the notifier call chain should be failed with some events
1571 notified, write the error code to "actions/<notifier event>/error".
1572
1573 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1574
1575 # cd /sys/kernel/debug/notifier-error-inject/netdev
1576 # echo -22 > actions/NETDEV_CHANGEMTU/error
1577 # ip link set eth0 mtu 1024
1578 RTNETLINK answers: Invalid argument
1579
1580 To compile this code as a module, choose M here: the module will
1581 be called netdev-notifier-error-inject.
1582
1583 If unsure, say N.
1584
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001585config FUNCTION_ERROR_INJECTION
1586 def_bool y
1587 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1588
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001589config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001590 bool "Fault-injection framework"
1591 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001592 help
1593 Provide fault-injection framework.
1594 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001595
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001596config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001597 bool "Fault-injection capability for kmalloc"
1598 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001599 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001600 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001601 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001602
Akinobu Mita933e3122006-12-08 02:39:45 -08001603config FAIL_PAGE_ALLOC
1604 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001605 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001606 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001607 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001608
Akinobu Mitac17bb492006-12-08 02:39:46 -08001609config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001610 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001611 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001612 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001613 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001614
Jens Axboe581d4e22008-09-14 05:56:33 -07001615config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d01432010-07-21 16:05:53 +09001616 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001617 depends on FAULT_INJECTION && BLOCK
1618 help
1619 Provide fault-injection capability on end IO handling. This
1620 will make the block layer "forget" an interrupt as configured,
1621 thus exercising the error handling.
1622
1623 Only works with drivers that use the generic timeout handling,
1624 for others it wont do anything.
1625
Davidlohr Buesoab51fba2015-06-29 23:26:02 -07001626config FAIL_FUTEX
1627 bool "Fault-injection capability for futexes"
1628 select DEBUG_FS
1629 depends on FAULT_INJECTION && FUTEX
1630 help
1631 Provide fault-injection capability for futexes.
1632
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001633config FAULT_INJECTION_DEBUG_FS
1634 bool "Debugfs entries for fault-injection capabilities"
1635 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1636 help
1637 Enable configuration of fault-injection capabilities via debugfs.
1638
Masami Hiramatsu4b1a29a2018-01-13 02:56:03 +09001639config FAIL_FUNCTION
1640 bool "Fault-injection capability for functions"
1641 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1642 help
1643 Provide function-based fault-injection capability.
1644 This will allow you to override a specific function with a return
1645 with given return value. As a result, function caller will see
1646 an error value and have to handle it. This is useful to test the
1647 error handling in various subsystems.
1648
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001649config FAIL_MMC_REQUEST
1650 bool "Fault-injection capability for MMC IO"
1651 depends on FAULT_INJECTION_DEBUG_FS && MMC
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001652 help
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001653 Provide fault-injection capability for MMC IO.
1654 This will make the mmc core return data errors. This is
1655 useful to test the error handling in the mmc block device
1656 and to test how the mmc host driver handles retries from
1657 the block device.
Akinobu Mita1df49002007-02-20 13:57:56 -08001658
Can Guo2d8e79c2018-06-25 01:05:49 -07001659config UFS_FAULT_INJECTION
1660 bool "Fault-injection capability for UFS IO"
1661 select DEBUG_FS
1662 depends on FAULT_INJECTION && SCSI_UFSHCD
1663 help
1664 Provide fault-injection capability for UFS IO.
1665 This will make the UFS host controller driver to randomly
1666 abort ongoing commands in the host controller, update OCS
1667 field according to the injected fatal error and can also
1668 forcefully hang the command indefinitely till upper layer
1669 timeout occurs. This is useful to test error handling in
1670 the UFS controller driver and test how the driver handles
1671 the retries from block/SCSI mid layer.
1672
Akinobu Mita1df49002007-02-20 13:57:56 -08001673config FAULT_INJECTION_STACKTRACE_FILTER
1674 bool "stacktrace filter for fault-injection capabilities"
1675 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001676 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001677 select STACKTRACE
Arnd Bergmanna687a532018-03-07 23:30:54 +01001678 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !X86
Akinobu Mita1df49002007-02-20 13:57:56 -08001679 help
1680 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001681
Arjan van de Ven97455122008-01-25 21:08:34 +01001682config LATENCYTOP
1683 bool "Latency measuring infrastructure"
Randy Dunlap625fdca2010-08-12 12:31:21 -07001684 depends on DEBUG_KERNEL
1685 depends on STACKTRACE_SUPPORT
1686 depends on PROC_FS
Josh Poimboeufa34a7662017-07-24 18:36:58 -05001687 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !X86
Arjan van de Ven97455122008-01-25 21:08:34 +01001688 select KALLSYMS
1689 select KALLSYMS_ALL
1690 select STACKTRACE
1691 select SCHEDSTATS
1692 select SCHED_DEBUG
Arjan van de Ven97455122008-01-25 21:08:34 +01001693 help
1694 Enable this option if you want to use the LatencyTOP tool
1695 to find out which userspace is blocking on what kernel operations.
1696
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001697source kernel/trace/Kconfig
1698
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001699config PROVIDE_OHCI1394_DMA_INIT
1700 bool "Remote debugging over FireWire early on boot"
1701 depends on PCI && X86
1702 help
1703 If you want to debug problems which hang or crash the kernel early
1704 on boot and the crashing machine has a FireWire port, you can use
1705 this feature to remotely access the memory of the crashed machine
1706 over FireWire. This employs remote DMA as part of the OHCI1394
1707 specification which is now the standard for FireWire controllers.
1708
1709 With remote DMA, you can monitor the printk buffer remotely using
1710 firescope and access all memory below 4GB using fireproxy from gdb.
1711 Even controlling a kernel debugger is possible using remote DMA.
1712
1713 Usage:
1714
1715 If ohci1394_dma=early is used as boot parameter, it will initialize
1716 all OHCI1394 controllers which are found in the PCI config space.
1717
1718 As all changes to the FireWire bus such as enabling and disabling
1719 devices cause a bus reset and thereby disable remote DMA for all
1720 devices, be sure to have the cable plugged and FireWire enabled on
1721 the debugging host before booting the debug target for debugging.
1722
1723 This code (~1k) is freed after boot. By then, the firewire stack
1724 in charge of the OHCI-1394 controllers should be used instead.
1725
1726 See Documentation/debugging-via-ohci1394.txt for more information.
1727
1728config DMA_API_DEBUG
1729 bool "Enable debugging of DMA-API usage"
Christoph Hellwigf616ab52018-05-09 06:53:49 +02001730 select NEED_DMA_MAP_STATE
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001731 help
1732 Enable this option to debug the use of the DMA API by device drivers.
1733 With this option you will be able to detect common bugs in device
1734 drivers like double-freeing of DMA mappings or freeing mappings that
1735 were never allocated.
1736
1737 This also attempts to catch cases where a page owned by DMA is
1738 accessed by the cpu in a way that could cause data corruption. For
1739 example, this enables cow_user_page() to check that the source page is
1740 not undergoing DMA.
1741
1742 This option causes a performance degradation. Use only if you want to
1743 debug device drivers and dma interactions.
1744
1745 If unsure, say N.
1746
Robin Murphy78c47832018-05-21 12:35:13 +01001747config DMA_API_DEBUG_SG
1748 bool "Debug DMA scatter-gather usage"
1749 default y
1750 depends on DMA_API_DEBUG
1751 help
1752 Perform extra checking that callers of dma_map_sg() have respected the
1753 appropriate segment length/boundary limits for the given device when
1754 preparing DMA scatterlists.
1755
1756 This is particularly likely to have been overlooked in cases where the
1757 dma_map_sg() API is used for general bulk mapping of pages rather than
1758 preparing literal scatter-gather descriptors, where there is a risk of
1759 unexpected behaviour from DMA API implementations if the scatterlist
1760 is technically out-of-spec.
1761
1762 If unsure, say N.
1763
Vincent Legolld3deafa2018-02-06 15:38:38 -08001764menuconfig RUNTIME_TESTING_MENU
1765 bool "Runtime Testing"
Anders Roxell908009e82018-02-21 14:46:05 -08001766 def_bool y
Vincent Legolld3deafa2018-02-06 15:38:38 -08001767
1768if RUNTIME_TESTING_MENU
Dave Hansen881c5142013-07-01 13:04:44 -07001769
1770config LKDTM
1771 tristate "Linux Kernel Dump Test Tool Module"
1772 depends on DEBUG_FS
1773 depends on BLOCK
Dave Hansen881c5142013-07-01 13:04:44 -07001774 help
1775 This module enables testing of the different dumping mechanisms by
1776 inducing system failures at predefined crash points.
1777 If you don't need it: say N
1778 Choose M here to compile this code as a module. The module will be
1779 called lkdtm.
1780
1781 Documentation on how to use the module can be found in
1782 Documentation/fault-injection/provoke-crashes.txt
1783
1784config TEST_LIST_SORT
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001785 tristate "Linked list sorting test"
1786 depends on DEBUG_KERNEL || m
Dave Hansen881c5142013-07-01 13:04:44 -07001787 help
1788 Enable this to turn on 'list_sort()' function test. This test is
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001789 executed only once during system boot (so affects only boot time),
1790 or at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001791
1792 If unsure, say N.
1793
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001794config TEST_SORT
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001795 tristate "Array-based sort test"
1796 depends on DEBUG_KERNEL || m
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001797 help
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001798 This option enables the self-test function of 'sort()' at boot,
1799 or at module load time.
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001800
1801 If unsure, say N.
1802
Dave Hansen881c5142013-07-01 13:04:44 -07001803config KPROBES_SANITY_TEST
1804 bool "Kprobes sanity tests"
1805 depends on DEBUG_KERNEL
1806 depends on KPROBES
Dave Hansen881c5142013-07-01 13:04:44 -07001807 help
1808 This option provides for testing basic kprobes functionality on
Masami Hiramatsu5a6cf772018-06-20 01:05:07 +09001809 boot. Samples of kprobe and kretprobe are inserted and
Dave Hansen881c5142013-07-01 13:04:44 -07001810 verified for functionality.
1811
1812 Say N if you are unsure.
1813
1814config BACKTRACE_SELF_TEST
1815 tristate "Self test for the backtrace code"
1816 depends on DEBUG_KERNEL
Dave Hansen881c5142013-07-01 13:04:44 -07001817 help
1818 This option provides a kernel module that can be used to test
1819 the kernel stack backtrace code. This option is not useful
1820 for distributions or general kernels, but only for kernel
1821 developers working on architecture code.
1822
1823 Note that if you want to also test saved backtraces, you will
1824 have to enable STACKTRACE as well.
1825
1826 Say N if you are unsure.
1827
Michel Lespinasse910a7422012-10-08 16:30:39 -07001828config RBTREE_TEST
1829 tristate "Red-Black tree test"
Cody P Schafer7c993e12013-09-11 14:25:19 -07001830 depends on DEBUG_KERNEL
Michel Lespinasse910a7422012-10-08 16:30:39 -07001831 help
1832 A benchmark measuring the performance of the rbtree library.
1833 Also includes rbtree invariant checks.
1834
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001835config INTERVAL_TREE_TEST
1836 tristate "Interval tree test"
Davidlohr Bueso0f789b62017-07-10 15:51:43 -07001837 depends on DEBUG_KERNEL
Chris Wilsona88cc102014-03-17 12:21:54 +00001838 select INTERVAL_TREE
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001839 help
1840 A benchmark measuring the performance of the interval tree library
1841
Greg Thelen623fd802013-11-12 15:08:34 -08001842config PERCPU_TEST
1843 tristate "Per cpu operations test"
1844 depends on m && DEBUG_KERNEL
1845 help
1846 Enable this option to build test module which validates per-cpu
1847 operations.
1848
1849 If unsure, say N.
1850
Dave Hansen881c5142013-07-01 13:04:44 -07001851config ATOMIC64_SELFTEST
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001852 tristate "Perform an atomic64_t self-test"
Dave Hansen881c5142013-07-01 13:04:44 -07001853 help
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001854 Enable this option to test the atomic64_t functions at boot or
1855 at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001856
1857 If unsure, say N.
1858
1859config ASYNC_RAID6_TEST
1860 tristate "Self test for hardware accelerated raid6 recovery"
1861 depends on ASYNC_RAID6_RECOV
1862 select ASYNC_MEMCPY
1863 ---help---
1864 This is a one-shot self test that permutes through the
1865 recovery of all the possible two disk failure scenarios for a
1866 N-disk array. Recovery is performed with the asynchronous
1867 raid6 recovery routines, and will optionally use an offload
1868 engine if one is available.
1869
1870 If unsure, say N.
1871
Andy Shevchenko64d1d772015-02-12 15:02:21 -08001872config TEST_HEXDUMP
1873 tristate "Test functions located in the hexdump module at runtime"
1874
Dave Hansen881c5142013-07-01 13:04:44 -07001875config TEST_STRING_HELPERS
1876 tristate "Test functions located in the string_helpers module at runtime"
1877
1878config TEST_KSTRTOX
1879 tristate "Test kstrto*() family of functions at runtime"
1880
Rasmus Villemoes707cc722015-11-06 16:30:29 -08001881config TEST_PRINTF
1882 tristate "Test printf() family of functions at runtime"
1883
David Decotigny5fd003f2016-02-19 09:24:00 -05001884config TEST_BITMAP
1885 tristate "Test bitmap_*() family of functions at runtime"
David Decotigny5fd003f2016-02-19 09:24:00 -05001886 help
1887 Enable this option to test the bitmap functions at boot.
1888
1889 If unsure, say N.
1890
Johannes Berg0e2dc702018-06-20 08:58:30 +02001891config TEST_BITFIELD
1892 tristate "Test bitfield functions at runtime"
1893 help
1894 Enable this option to test the bitfield functions at boot.
1895
1896 If unsure, say N.
1897
Andy Shevchenkocfaff0e2016-05-30 17:40:41 +03001898config TEST_UUID
1899 tristate "Test functions located in the uuid module at runtime"
1900
Rasmus Villemoes455a35a2018-05-08 00:36:28 +02001901config TEST_OVERFLOW
1902 tristate "Test check_*_overflow() functions at runtime"
1903
Thomas Graf7e1e7762014-08-02 11:47:44 +02001904config TEST_RHASHTABLE
Geert Uytterhoeven9d6dbe12015-01-29 15:40:25 +01001905 tristate "Perform selftest on resizable hash table"
Thomas Graf7e1e7762014-08-02 11:47:44 +02001906 help
1907 Enable this option to test the rhashtable functions at boot.
1908
1909 If unsure, say N.
1910
George Spelvin468a9422016-05-26 22:11:51 -04001911config TEST_HASH
1912 tristate "Perform selftest on hash functions"
George Spelvin468a9422016-05-26 22:11:51 -04001913 help
Jason A. Donenfeld2c956a62017-01-08 13:54:00 +01001914 Enable this option to test the kernel's integer (<linux/hash.h>),
1915 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
1916 hash functions on boot (or module load).
George Spelvin468a9422016-05-26 22:11:51 -04001917
1918 This is intended to help people writing architecture-specific
1919 optimized versions. If unsure, say N.
1920
Matthew Wilcox8ab8ba32018-06-18 16:59:29 -04001921config TEST_IDA
1922 tristate "Perform selftest on IDA functions"
1923
Jiri Pirko44091d22017-02-03 10:29:06 +01001924config TEST_PARMAN
1925 tristate "Perform selftest on priority array manager"
Jiri Pirko44091d22017-02-03 10:29:06 +01001926 depends on PARMAN
1927 help
1928 Enable this option to test priority array manager on boot
1929 (or module load).
1930
1931 If unsure, say N.
1932
Valentin Rothberg8a6f0b42014-10-13 15:51:38 -07001933config TEST_LKM
Kees Cook93e9ef82014-01-23 15:54:37 -08001934 tristate "Test module loading with 'hello world' module"
Kees Cook93e9ef82014-01-23 15:54:37 -08001935 depends on m
1936 help
1937 This builds the "test_module" module that emits "Hello, world"
1938 on printk when loaded. It is designed to be used for basic
1939 evaluation of the module loading subsystem (for example when
1940 validating module verification). It lacks any extra dependencies,
1941 and will not normally be loaded by the system unless explicitly
1942 requested by name.
1943
1944 If unsure, say N.
1945
Kees Cook3e2a4c12014-01-23 15:54:38 -08001946config TEST_USER_COPY
1947 tristate "Test user/kernel boundary protections"
Kees Cook3e2a4c12014-01-23 15:54:38 -08001948 depends on m
1949 help
1950 This builds the "test_user_copy" module that runs sanity checks
1951 on the copy_to/from_user infrastructure, making sure basic
1952 user/kernel boundary testing is working. If it fails to load,
1953 a regression has been detected in the user/kernel memory boundary
1954 protections.
1955
1956 If unsure, say N.
1957
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001958config TEST_BPF
1959 tristate "Test BPF filter functionality"
Randy Dunlap98920ba2014-05-13 09:58:44 -07001960 depends on m && NET
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001961 help
1962 This builds the "test_bpf" module that runs various test vectors
1963 against the BPF interpreter or BPF JIT compiler depending on the
1964 current setting. This is in particular useful for BPF JIT compiler
1965 development, but also to run regression tests against changes in
Alexei Starovoitov3c731eb2014-09-26 00:17:07 -07001966 the interpreter code. It also enables test stubs for eBPF maps and
1967 verifier used by user space verifier testsuite.
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001968
1969 If unsure, say N.
1970
Yury Norovdceeb3e2018-02-06 15:38:27 -08001971config FIND_BIT_BENCHMARK
Yury Norov4441fca2017-11-17 15:28:31 -08001972 tristate "Test find_bit functions"
Yury Norov4441fca2017-11-17 15:28:31 -08001973 help
1974 This builds the "test_find_bit" module that measure find_*_bit()
1975 functions performance.
1976
1977 If unsure, say N.
1978
Kees Cook0a8adf52014-07-14 14:38:12 -07001979config TEST_FIRMWARE
1980 tristate "Test firmware loading via userspace interface"
Kees Cook0a8adf52014-07-14 14:38:12 -07001981 depends on FW_LOADER
1982 help
1983 This builds the "test_firmware" module that creates a userspace
1984 interface for testing firmware loading. This can be used to
1985 control the triggering of firmware loading without needing an
1986 actual firmware-using device. The contents can be rechecked by
1987 userspace.
1988
1989 If unsure, say N.
1990
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07001991config TEST_SYSCTL
1992 tristate "sysctl test driver"
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07001993 depends on PROC_SYSCTL
1994 help
1995 This builds the "test_sysctl" module. This driver enables to test the
1996 proc sysctl interfaces available to drivers safely without affecting
1997 production knobs which might alter system functionality.
1998
1999 If unsure, say N.
2000
David Rileye704f932014-06-16 14:58:32 -07002001config TEST_UDELAY
2002 tristate "udelay test driver"
David Rileye704f932014-06-16 14:58:32 -07002003 help
2004 This builds the "udelay_test" module that helps to make sure
2005 that udelay() is working properly.
2006
2007 If unsure, say N.
2008
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02002009config TEST_STATIC_KEYS
2010 tristate "Test static keys"
Jason Baron579e1ac2015-07-30 03:59:44 +00002011 depends on m
2012 help
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02002013 Test the static key interfaces.
Jason Baron579e1ac2015-07-30 03:59:44 +00002014
2015 If unsure, say N.
2016
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002017config TEST_KMOD
2018 tristate "kmod stress tester"
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002019 depends on m
2020 depends on BLOCK && (64BIT || LBDAF) # for XFS, BTRFS
2021 depends on NETDEVICES && NET_CORE && INET # for TUN
YueHaibingce900dd2019-04-25 22:23:44 -07002022 depends on BLOCK
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07002023 select TEST_LKM
2024 select XFS_FS
2025 select TUN
2026 select BTRFS_FS
2027 help
2028 Test the kernel's module loading mechanism: kmod. kmod implements
2029 support to load modules using the Linux kernel's usermode helper.
2030 This test provides a series of tests against kmod.
2031
2032 Although technically you can either build test_kmod as a module or
2033 into the kernel we disallow building it into the kernel since
2034 it stress tests request_module() and this will very likely cause
2035 some issues by taking over precious threads available from other
2036 module load requests, ultimately this could be fatal.
2037
2038 To run tests run:
2039
2040 tools/testing/selftests/kmod/kmod.sh --help
2041
2042 If unsure, say N.
2043
Florian Fainellie4dace32017-09-08 16:15:31 -07002044config TEST_DEBUG_VIRTUAL
2045 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2046 depends on DEBUG_VIRTUAL
2047 help
2048 Test the kernel's ability to detect incorrect calls to
2049 virt_to_phys() done against the non-linear part of the
2050 kernel's virtual address map.
2051
2052 If unsure, say N.
2053
Vincent Legolld3deafa2018-02-06 15:38:38 -08002054endif # RUNTIME_TESTING_MENU
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002055
2056config MEMTEST
2057 bool "Memtest"
2058 depends on HAVE_MEMBLOCK
2059 ---help---
2060 This option adds a kernel parameter 'memtest', which allows memtest
2061 to be set.
2062 memtest=0, mean disabled; -- default
2063 memtest=1, mean do 1 test pattern;
2064 ...
2065 memtest=17, mean do 17 test patterns.
2066 If you are unsure how to answer this question, answer N.
2067
2068config BUG_ON_DATA_CORRUPTION
2069 bool "Trigger a BUG when data corruption is detected"
2070 select DEBUG_LIST
2071 help
2072 Select this option if the kernel should BUG when it encounters
2073 data corruption in kernel memory structures when they get checked
2074 for validity.
2075
2076 If unsure, say N.
Florian Fainellie4dace32017-09-08 16:15:31 -07002077
Syed Rameez Mustafa8af99422013-07-15 11:52:09 -07002078config PANIC_ON_DATA_CORRUPTION
2079 bool "Cause a Kernel Panic When Data Corruption is detected"
2080 help
2081 Select this option to upgrade warnings for potentially
2082 recoverable data corruption scenarios to system-halting panics,
2083 for easier detection and debug.
2084
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07002085source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02002086
2087source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02002088
Andrey Ryabininc6d30852016-01-20 15:00:55 -08002089source "lib/Kconfig.ubsan"
2090
Dan Williams21266be2015-11-19 18:19:29 -08002091config ARCH_HAS_DEVMEM_IS_ALLOWED
2092 bool
2093
2094config STRICT_DEVMEM
2095 bool "Filter access to /dev/mem"
Dave Young6b2a65c2016-12-12 16:46:14 -08002096 depends on MMU && DEVMEM
Dan Williams21266be2015-11-19 18:19:29 -08002097 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
Arnd Bergmanna687a532018-03-07 23:30:54 +01002098 default y if PPC || X86 || ARM64
Dan Williams21266be2015-11-19 18:19:29 -08002099 ---help---
2100 If this option is disabled, you allow userspace (root) access to all
2101 of memory, including kernel and userspace memory. Accidental
2102 access to this is obviously disastrous, but specific access can
2103 be used by people debugging the kernel. Note that with PAT support
2104 enabled, even in this case there are restrictions on /dev/mem
2105 use due to the cache aliasing requirements.
2106
Dan Williams90a545e2015-11-23 15:49:03 -08002107 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
2108 file only allows userspace access to PCI space and the BIOS code and
2109 data regions. This is sufficient for dosemu and X and all common
2110 users of /dev/mem.
2111
2112 If in doubt, say Y.
2113
2114config IO_STRICT_DEVMEM
2115 bool "Filter I/O access to /dev/mem"
2116 depends on STRICT_DEVMEM
Dan Williams90a545e2015-11-23 15:49:03 -08002117 ---help---
2118 If this option is disabled, you allow userspace (root) access to all
2119 io-memory regardless of whether a driver is actively using that
2120 range. Accidental access to this is obviously disastrous, but
2121 specific access can be used by people debugging kernel drivers.
2122
Dan Williams21266be2015-11-19 18:19:29 -08002123 If this option is switched on, the /dev/mem file only allows
Dan Williams90a545e2015-11-23 15:49:03 -08002124 userspace access to *idle* io-memory ranges (see /proc/iomem) This
2125 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
2126 if the driver using a given range cannot be disabled.
Dan Williams21266be2015-11-19 18:19:29 -08002127
2128 If in doubt, say Y.
Christoph Hellwig06ec64b2018-07-31 13:39:31 +02002129
2130source "arch/$(SRCARCH)/Kconfig.debug"
2131
2132endmenu # Kernel hacking