blob: d4df5b24d75e107061fe8db387948d5dc5c785c4 [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
149endmenu # "printk and dmesg options"
150
Dave Hansen6dfc0662013-07-01 13:04:46 -0700151menu "Compile-time checks and compiler options"
152
153config DEBUG_INFO
154 bool "Compile the kernel with debug info"
Linus Torvalds12b13832014-02-04 12:20:01 -0800155 depends on DEBUG_KERNEL && !COMPILE_TEST
Dave Hansen6dfc0662013-07-01 13:04:46 -0700156 help
157 If you say Y here the resulting kernel image will include
158 debugging info resulting in a larger kernel image.
159 This adds debug symbols to the kernel and modules (gcc -g), and
160 is needed if you intend to use kernel crashdump or binary object
161 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
162 Say Y here only if you plan to debug the kernel.
163
164 If unsure, say N.
165
166config DEBUG_INFO_REDUCED
167 bool "Reduce debugging information"
168 depends on DEBUG_INFO
169 help
170 If you say Y here gcc is instructed to generate less debugging
171 information for structure types. This means that tools that
172 need full debugging information (like kgdb or systemtap) won't
173 be happy. But if you merely need debugging information to
174 resolve line numbers there is no loss. Advantage is that
175 build directory object sizes shrink dramatically over a full
176 DEBUG_INFO build and compile times are reduced too.
177 Only works with newer gcc versions.
178
Andi Kleen866ced92014-07-30 20:50:18 +0200179config DEBUG_INFO_SPLIT
180 bool "Produce split debuginfo in .dwo files"
Arnd Bergmanna687a532018-03-07 23:30:54 +0100181 depends on DEBUG_INFO
Andi Kleen866ced92014-07-30 20:50:18 +0200182 help
183 Generate debug info into separate .dwo files. This significantly
184 reduces the build directory size for builds with DEBUG_INFO,
185 because it stores the information only once on disk in .dwo
186 files instead of multiple times in object files and executables.
187 In addition the debug information is also compressed.
188
189 Requires recent gcc (4.7+) and recent gdb/binutils.
190 Any tool that packages or reads debug information would need
191 to know about the .dwo files and include them.
192 Incompatible with older versions of ccache.
193
Andi Kleenbfaf2dd2014-07-30 20:50:19 +0200194config DEBUG_INFO_DWARF4
195 bool "Generate dwarf4 debuginfo"
196 depends on DEBUG_INFO
197 help
198 Generate dwarf4 debug info. This requires recent versions
199 of gcc and gdb. It makes the debug information larger.
200 But it significantly improves the success of resolving
201 variables in gdb on optimized code.
202
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800203config GDB_SCRIPTS
204 bool "Provide GDB scripts for kernel debugging"
205 depends on DEBUG_INFO
206 help
207 This creates the required links to GDB helper scripts in the
208 build directory. If you load vmlinux into gdb, the helper
209 scripts will be automatically imported by gdb as well, and
210 additional functions are available to analyze a Linux kernel
Andreas Platschek700199b02016-12-14 15:05:40 -0800211 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
212 for further details.
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800213
Andrew Mortoncebc04b2006-08-14 22:43:18 -0700214config ENABLE_MUST_CHECK
215 bool "Enable __must_check logic"
216 default y
217 help
218 Enable the __must_check logic in the kernel build. Disable this to
219 suppress the "warning: ignoring return value of 'foo', declared with
220 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221
Andi Kleen35bb5b12008-02-22 15:15:03 +0100222config FRAME_WARN
223 int "Warn for stack frames larger than (needs gcc 4.4)"
224 range 0 8192
Arnd Bergmanne7c52b82018-02-06 15:41:41 -0800225 default 3072 if KASAN_EXTRA
Kees Cook0e07f662016-10-27 17:46:41 -0700226 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
Helge Deller432654d2017-09-11 21:41:43 +0200227 default 1280 if (!64BIT && PARISC)
228 default 1024 if (!64BIT && !PARISC)
Andi Kleen35bb5b12008-02-22 15:15:03 +0100229 default 2048 if 64BIT
230 help
231 Tell gcc to warn at build time for stack frames larger than this.
232 Setting this too low will cause a lot of warnings.
233 Setting it to 0 disables the warning.
234 Requires gcc 4.4
235
Randy Dunlap99657c72009-09-18 12:49:22 -0700236config STRIP_ASM_SYMS
237 bool "Strip assembler-generated symbols during link"
238 default n
239 help
240 Strip internal assembler-generated symbols during a link (symbols
241 that look like '.Lxxx') so they don't pollute the output of
242 get_wchan() and suchlike.
243
Andi Kleen1873e872012-03-28 11:51:18 -0700244config READABLE_ASM
245 bool "Generate readable assembler code"
246 depends on DEBUG_KERNEL
247 help
248 Disable some compiler optimizations that tend to generate human unreadable
249 assembler output. This may make the kernel slightly slower, but it helps
250 to keep kernel developers who have to stare a lot at assembler listings
251 sane.
252
Arjan van de Venf71d20e2006-06-28 04:26:45 -0700253config UNUSED_SYMBOLS
254 bool "Enable unused/obsolete exported symbols"
255 default y if X86
256 help
257 Unused but exported symbols make the kernel needlessly bigger. For
258 that reason most of these unused exports will soon be removed. This
259 option is provided temporarily to provide a transition period in case
260 some external kernel module needs one of these symbols anyway. If you
261 encounter such a case in your module, consider if you are actually
262 using the right API. (rationale: since nobody in the kernel is using
263 this in a module, there is a pretty good chance it's actually the
264 wrong interface to use). If you really need the symbol, please send a
265 mail to the linux kernel mailing list mentioning the symbol and why
266 you really need it, and what the merge plan to the mainline kernel for
267 your module is.
268
Joonsoo Kim48c96a32014-12-12 16:56:01 -0800269config PAGE_OWNER
270 bool "Track page owner"
271 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
272 select DEBUG_FS
273 select STACKTRACE
Joonsoo Kimf2ca0b52016-07-26 15:23:55 -0700274 select STACKDEPOT
Joonsoo Kim48c96a32014-12-12 16:56:01 -0800275 select PAGE_EXTENSION
276 help
277 This keeps track of what call chain is the owner of a page, may
278 help to find bare alloc_page(s) leaks. Even if you include this
279 feature on your build, it is disabled in default. You should pass
280 "page_owner=on" to boot parameter in order to enable it. Eats
281 a fair amount of memory if enabled. See tools/vm/page_owner_sort.c
282 for user-space helper.
283
284 If unsure, say N.
285
Don Mullisbf4735a2006-12-10 02:18:37 -0800286config DEBUG_FS
287 bool "Debug Filesystem"
Don Mullisbf4735a2006-12-10 02:18:37 -0800288 help
289 debugfs is a virtual file system that kernel developers use to put
290 debugging files into. Enable this option to be able to read and
291 write to these files.
292
Robert P. J. Dayff543332008-05-20 00:06:00 +0200293 For detailed documentation on the debugfs API, see
Mauro Carvalho Chehabe1b4fc72017-05-14 12:04:55 -0300294 Documentation/filesystems/.
Robert P. J. Dayff543332008-05-20 00:06:00 +0200295
Don Mullisbf4735a2006-12-10 02:18:37 -0800296 If unsure, say N.
297
298config HEADERS_CHECK
299 bool "Run 'make headers_check' when building vmlinux"
300 depends on !UML
301 help
302 This option will extract the user-visible kernel headers whenever
303 building the kernel, and will run basic sanity checks on them to
304 ensure that exported files do not attempt to include files which
305 were not exported, etc.
306
307 If you're making modifications to header files which are
308 relevant for userspace, say 'Y', and check the headers
309 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
310 your build tree), to make sure they're suitable.
311
Sam Ravnborg91341d42008-01-21 21:31:44 +0100312config DEBUG_SECTION_MISMATCH
313 bool "Enable full Section mismatch analysis"
Sam Ravnborg91341d42008-01-21 21:31:44 +0100314 help
315 The section mismatch analysis checks if there are illegal
316 references from one section to another section.
Michael Wittene809ab02011-04-17 04:08:48 +0000317 During linktime or runtime, some sections are dropped;
318 any use of code/data previously in these sections would
Sam Ravnborg91341d42008-01-21 21:31:44 +0100319 most likely result in an oops.
Michael Wittene809ab02011-04-17 04:08:48 +0000320 In the code, functions and variables are annotated with
Paul Gortmaker0db06282013-06-19 14:53:51 -0400321 __init,, etc. (see the full list in include/linux/init.h),
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100322 which results in the code/data being placed in specific sections.
Michael Wittene809ab02011-04-17 04:08:48 +0000323 The section mismatch analysis is always performed after a full
324 kernel build, and enabling this option causes the following
325 additional steps to occur:
326 - Add the option -fno-inline-functions-called-once to gcc commands.
327 When inlining a function annotated with __init in a non-init
328 function, we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100329 the analysis would not catch the illegal reference.
Michael Wittene809ab02011-04-17 04:08:48 +0000330 This option tells gcc to inline less (but it does result in
331 a larger kernel).
Nicholas Pigginf49821e2018-02-11 00:25:04 +1000332 - Run the section mismatch analysis for each module/built-in.a file.
Michael Wittene809ab02011-04-17 04:08:48 +0000333 When we run the section mismatch analysis on vmlinux.o, we
Uwe Kleine-König67797b92016-09-09 10:04:58 +0200334 lose valuable information about where the mismatch was
Sam Ravnborg91341d42008-01-21 21:31:44 +0100335 introduced.
Nicholas Pigginf49821e2018-02-11 00:25:04 +1000336 Running the analysis for each module/built-in.a file
Michael Wittene809ab02011-04-17 04:08:48 +0000337 tells where the mismatch happens much closer to the
338 source. The drawback is that the same mismatch is
339 reported at least twice.
340 - Enable verbose reporting from modpost in order to help resolve
341 the section mismatches that are reported.
Sam Ravnborg91341d42008-01-21 21:31:44 +0100342
Nicolas Boichat47490ec2015-10-06 09:44:42 +1030343config SECTION_MISMATCH_WARN_ONLY
344 bool "Make section mismatch errors non-fatal"
345 default y
346 help
347 If you say N here, the build process will fail if there are any
348 section mismatch, instead of just throwing warnings.
349
350 If unsure, say Y.
351
Dave Hansen6dfc0662013-07-01 13:04:46 -0700352#
353# Select this config option from the architecture Kconfig, if it
354# is preferred to always offer frame pointers as a config
355# option on the architecture (regardless of KERNEL_DEBUG):
356#
357config ARCH_WANT_FRAME_POINTERS
358 bool
Dave Hansen6dfc0662013-07-01 13:04:46 -0700359
360config FRAME_POINTER
361 bool "Compile the kernel with frame pointers"
Arnd Bergmanna687a532018-03-07 23:30:54 +0100362 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
Dave Hansen6dfc0662013-07-01 13:04:46 -0700363 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
364 help
365 If you say Y here the resulting kernel image will be slightly
366 larger and slower, but it gives very useful debugging information
367 in case of kernel bugs. (precise oopses/stacktraces/warnings)
368
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600369config STACK_VALIDATION
370 bool "Compile-time stack metadata validation"
371 depends on HAVE_STACK_VALIDATION
372 default n
373 help
374 Add compile-time checks to validate stack metadata, including frame
375 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
376 that runtime stack traces are more reliable.
377
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500378 This is also a prerequisite for generation of ORC unwind data, which
Josh Poimboeuf11af8472017-10-13 15:02:00 -0500379 is needed for CONFIG_UNWINDER_ORC.
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500380
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600381 For more information, see
382 tools/objtool/Documentation/stack-validation.txt.
383
Dave Hansen6dfc0662013-07-01 13:04:46 -0700384config DEBUG_FORCE_WEAK_PER_CPU
385 bool "Force weak per-cpu definitions"
386 depends on DEBUG_KERNEL
387 help
388 s390 and alpha require percpu variables in modules to be
389 defined weak to work around addressing range issue which
390 puts the following two restrictions on percpu variable
391 definitions.
392
393 1. percpu symbols must be unique whether static or not
394 2. percpu variables can't be defined inside a function
395
396 To ensure that generic code follows the above rules, this
397 option forces all percpu variables to be defined as weak.
398
399endmenu # "Compiler options"
400
401config MAGIC_SYSRQ
402 bool "Magic SysRq key"
403 depends on !UML
404 help
405 If you say Y here, you will have some control over the system even
406 if the system crashes for example during kernel debugging (e.g., you
407 will be able to flush the buffer cache to disk, reboot the system
408 immediately or dump some status information). This is accomplished
409 by pressing various keys while holding SysRq (Alt+PrintScreen). It
410 also works on a serial console (on PC hardware at least), if you
411 send a BREAK and then within 5 seconds a command keypress. The
Hans Holmbergf8998c22017-03-16 09:37:32 +0100412 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
413 Don't say Y unless you really know what this hack does.
Dave Hansen6dfc0662013-07-01 13:04:46 -0700414
Ben Hutchings8eaede42013-10-07 01:05:46 +0100415config MAGIC_SYSRQ_DEFAULT_ENABLE
416 hex "Enable magic SysRq key functions by default"
417 depends on MAGIC_SYSRQ
418 default 0x1
419 help
420 Specifies which SysRq key functions are enabled by default.
421 This may be set to 1 or 0 to enable or disable them all, or
Hans Holmbergf8998c22017-03-16 09:37:32 +0100422 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
Ben Hutchings8eaede42013-10-07 01:05:46 +0100423
Felix Fietkau732dbf32016-12-22 08:31:34 +0100424config MAGIC_SYSRQ_SERIAL
425 bool "Enable magic SysRq key over serial"
426 depends on MAGIC_SYSRQ
427 default y
428 help
429 Many embedded boards have a disconnected TTL level serial which can
430 generate some garbage that can lead to spurious false sysrq detects.
431 This option allows you to decide whether you want to enable the
432 magic SysRq key.
433
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800434config DEBUG_KERNEL
435 bool "Kernel debugging"
436 help
437 Say Y here if you are developing drivers or trying to debug and
438 identify kernel problems.
439
Dave Hansen0610c8a2013-07-01 13:04:43 -0700440menu "Memory Debugging"
David Woodhousea304e1b2007-02-12 00:52:00 -0800441
Masahiro Yamada8636a1f2018-12-11 20:01:04 +0900442source "mm/Kconfig.debug"
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800443
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700444config DEBUG_OBJECTS
445 bool "Debug object operations"
446 depends on DEBUG_KERNEL
447 help
448 If you say Y here, additional code will be inserted into the
449 kernel to track the life time of various objects and validate
450 the operations on those objects.
451
452config DEBUG_OBJECTS_SELFTEST
453 bool "Debug objects selftest"
454 depends on DEBUG_OBJECTS
455 help
456 This enables the selftest of the object debug code.
457
458config DEBUG_OBJECTS_FREE
459 bool "Debug objects in freed memory"
460 depends on DEBUG_OBJECTS
461 help
462 This enables checks whether a k/v free operation frees an area
463 which contains an object which has not been deactivated
464 properly. This can make kmalloc/kfree-intensive workloads
465 much slower.
466
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700467config DEBUG_OBJECTS_TIMERS
468 bool "Debug timer objects"
469 depends on DEBUG_OBJECTS
470 help
471 If you say Y here, additional code will be inserted into the
472 timer routines to track the life time of timer objects and
473 validate the timer operations.
474
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900475config DEBUG_OBJECTS_WORK
476 bool "Debug work objects"
477 depends on DEBUG_OBJECTS
478 help
479 If you say Y here, additional code will be inserted into the
480 work queue routines to track the life time of work objects and
481 validate the work operations.
482
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400483config DEBUG_OBJECTS_RCU_HEAD
484 bool "Debug RCU callbacks objects"
Mathieu Desnoyersfc2ecf72011-02-23 09:42:14 -0800485 depends on DEBUG_OBJECTS
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400486 help
487 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
488
Tejun Heoe2852ae2010-10-26 14:23:05 -0700489config DEBUG_OBJECTS_PERCPU_COUNTER
490 bool "Debug percpu counter objects"
491 depends on DEBUG_OBJECTS
492 help
493 If you say Y here, additional code will be inserted into the
494 percpu counter routines to track the life time of percpu counter
495 objects and validate the percpu counter operations.
496
Ingo Molnar3ae70202008-11-26 10:02:00 +0100497config DEBUG_OBJECTS_ENABLE_DEFAULT
498 int "debug_objects bootup default value (0-1)"
499 range 0 1
500 default "1"
501 depends on DEBUG_OBJECTS
502 help
503 Debug objects boot parameter default value
504
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800506 bool "Debug slab memory allocations"
Levin, Alexander (Sasha Levin)4675ff02017-11-15 17:36:02 -0800507 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 help
509 Say Y here to have the kernel do limited verification on memory
510 allocation as well as poisoning memory on free to catch use of freed
511 memory. This can make kmalloc/kfree-intensive workloads much slower.
512
Al Viro871751e2006-03-25 03:06:39 -0800513config DEBUG_SLAB_LEAK
514 bool "Memory leak debugging"
515 depends on DEBUG_SLAB
516
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700517config SLUB_DEBUG_ON
518 bool "SLUB debugging on by default"
Levin, Alexander (Sasha Levin)4675ff02017-11-15 17:36:02 -0800519 depends on SLUB && SLUB_DEBUG
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700520 default n
521 help
522 Boot with debugging on by default. SLUB boots by default with
523 the runtime debug capabilities switched off. Enabling this is
524 equivalent to specifying the "slub_debug" parameter on boot.
525 There is no support for more fine grained debug control like
526 possible with slub_debug=xxx. SLUB debugging may be switched
527 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
528 "slub_debug=-".
529
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800530config SLUB_STATS
531 default n
532 bool "Enable SLUB performance statistics"
Christoph Lameterab4d5ed2010-10-05 13:57:26 -0500533 depends on SLUB && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800534 help
535 SLUB statistics are useful to debug SLUBs allocation behavior in
536 order find ways to optimize the allocator. This should never be
537 enabled for production use since keeping statistics slows down
538 the allocator by a few percentage points. The slabinfo command
539 supports the determination of the most active slabs to figure
540 out which slabs are relevant to a particular load.
541 Try running: slabinfo -DA
542
Catalin Marinasb69ec422012-10-08 16:28:11 -0700543config HAVE_DEBUG_KMEMLEAK
544 bool
545
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100546config DEBUG_KMEMLEAK
547 bool "Kernel memory leak detector"
Kees Cook525c1f92013-01-16 18:54:16 -0800548 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
Catalin Marinas79e0d9b2011-04-27 17:06:19 +0100549 select DEBUG_FS
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100550 select STACKTRACE if STACKTRACE_SUPPORT
551 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800552 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100553 help
554 Say Y here if you want to enable the memory leak
555 detector. The memory allocation/freeing is traced in a way
556 similar to the Boehm's conservative garbage collector, the
557 difference being that the orphan objects are not freed but
558 only shown in /sys/kernel/debug/kmemleak. Enabling this
559 feature will introduce an overhead to memory
Andreas Platschek700199b02016-12-14 15:05:40 -0800560 allocations. See Documentation/dev-tools/kmemleak.rst for more
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100561 details.
562
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100563 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
564 of finding leaks due to the slab objects poisoning.
565
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100566 In order to access the kmemleak file, debugfs needs to be
567 mounted (usually at /sys/kernel/debug).
568
Catalin Marinasa9d90582009-06-25 10:16:11 +0100569config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
570 int "Maximum kmemleak early log entries"
571 depends on DEBUG_KMEMLEAK
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200572 range 200 40000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100573 default 400
574 help
575 Kmemleak must track all the memory allocations to avoid
576 reporting false positives. Since memory may be allocated or
577 freed before kmemleak is initialised, an early log buffer is
578 used to store these actions. If kmemleak reports "early log
579 buffer exceeded", please increase this value.
580
Catalin Marinas0822ee42009-06-11 13:24:14 +0100581config DEBUG_KMEMLEAK_TEST
582 tristate "Simple test for the kernel memory leak detector"
Daniel Baluta97182692011-04-04 15:06:44 -0700583 depends on DEBUG_KMEMLEAK && m
Catalin Marinas0822ee42009-06-11 13:24:14 +0100584 help
Daniel Baluta97182692011-04-04 15:06:44 -0700585 This option enables a module that explicitly leaks memory.
Catalin Marinas0822ee42009-06-11 13:24:14 +0100586
587 If unsure, say N.
588
Jason Baronab0155a2010-07-19 11:54:17 +0100589config DEBUG_KMEMLEAK_DEFAULT_OFF
590 bool "Default kmemleak to off"
591 depends on DEBUG_KMEMLEAK
592 help
593 Say Y here to disable kmemleak by default. It can then be enabled
594 on the command line via kmemleak=on.
595
Sri Krishna chowdaryd53ce042018-12-28 00:38:54 -0800596config DEBUG_KMEMLEAK_AUTO_SCAN
597 bool "Enable kmemleak auto scan thread on boot up"
598 default y
599 depends on DEBUG_KMEMLEAK
600 help
601 Depending on the cpu, kmemleak scan may be cpu intensive and can
602 stall user tasks at times. This option enables/disables automatic
603 kmemleak scan at boot up.
604
605 Say N here to disable kmemleak auto scan thread to stop automatic
606 scanning. Disabling this option disables automatic reporting of
607 memory leaks.
608
609 If unsure, say Y.
610
Dave Hansen0610c8a2013-07-01 13:04:43 -0700611config DEBUG_STACK_USAGE
612 bool "Stack utilization instrumentation"
Helge Deller6c31da32016-03-19 17:54:10 +0100613 depends on DEBUG_KERNEL && !IA64
Dave Hansen0610c8a2013-07-01 13:04:43 -0700614 help
615 Enables the display of the minimum amount of free stack which each
616 task has ever had available in the sysrq-T and sysrq-P debug output.
617
618 This option will slow down process creation somewhat.
619
620config DEBUG_VM
621 bool "Debug VM"
622 depends on DEBUG_KERNEL
623 help
624 Enable this to turn on extended checks in the virtual-memory system
625 that may impact performance.
626
627 If unsure, say N.
628
Davidlohr Bueso4f115142014-06-04 16:06:46 -0700629config DEBUG_VM_VMACACHE
630 bool "Debug VMA caching"
631 depends on DEBUG_VM
632 help
633 Enable this to turn on VMA caching debug information. Doing so
634 can cause significant overhead, so only enable it in non-production
635 environments.
636
637 If unsure, say N.
638
Dave Hansen0610c8a2013-07-01 13:04:43 -0700639config DEBUG_VM_RB
640 bool "Debug VM red-black trees"
641 depends on DEBUG_VM
642 help
Davidlohr Buesoa663dad2014-04-18 15:07:22 -0700643 Enable VM red-black tree debugging information and extra validations.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700644
645 If unsure, say N.
646
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800647config DEBUG_VM_PGFLAGS
648 bool "Debug page-flags operations"
649 depends on DEBUG_VM
650 help
651 Enables extra validation on page flags operations.
652
653 If unsure, say N.
654
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800655config ARCH_HAS_DEBUG_VIRTUAL
656 bool
657
Dave Hansen0610c8a2013-07-01 13:04:43 -0700658config DEBUG_VIRTUAL
659 bool "Debug VM translations"
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800660 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
Dave Hansen0610c8a2013-07-01 13:04:43 -0700661 help
662 Enable some costly sanity checks in virtual to page code. This can
663 catch mistakes with virt_to_page() and friends.
664
665 If unsure, say N.
666
667config DEBUG_NOMMU_REGIONS
668 bool "Debug the global anon/private NOMMU mapping region tree"
669 depends on DEBUG_KERNEL && !MMU
670 help
671 This option causes the global tree of anonymous and private mapping
672 regions to be regularly checked for invalid topology.
673
674config DEBUG_MEMORY_INIT
675 bool "Debug memory initialisation" if EXPERT
676 default !EXPERT
677 help
678 Enable this for additional checks during memory initialisation.
679 The sanity checks verify aspects of the VM such as the memory model
680 and other information provided by the architecture. Verbose
681 information will be printed at KERN_DEBUG loglevel depending
682 on the mminit_loglevel= command-line option.
683
684 If unsure, say Y
685
686config MEMORY_NOTIFIER_ERROR_INJECT
687 tristate "Memory hotplug notifier error injection module"
688 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
689 help
690 This option provides the ability to inject artificial errors to
691 memory hotplug notifier chain callbacks. It is controlled through
692 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
693
694 If the notifier call chain should be failed with some events
695 notified, write the error code to "actions/<notifier event>/error".
696
697 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
698
699 # cd /sys/kernel/debug/notifier-error-inject/memory
700 # echo -12 > actions/MEM_GOING_OFFLINE/error
701 # echo offline > /sys/devices/system/memory/memoryXXX/state
702 bash: echo: write error: Cannot allocate memory
703
704 To compile this code as a module, choose M here: the module will
705 be called memory-notifier-error-inject.
706
707 If unsure, say N.
708
709config DEBUG_PER_CPU_MAPS
710 bool "Debug access to per_cpu maps"
711 depends on DEBUG_KERNEL
712 depends on SMP
713 help
714 Say Y to verify that the per_cpu map being accessed has
715 been set up. This adds a fair amount of code to kernel memory
716 and decreases performance.
717
718 Say N if unsure.
719
720config DEBUG_HIGHMEM
721 bool "Highmem debugging"
722 depends on DEBUG_KERNEL && HIGHMEM
723 help
Geert Uytterhoevenb1357c92014-04-14 18:55:50 +0200724 This option enables additional error checking for high memory
725 systems. Disable for production systems.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700726
727config HAVE_DEBUG_STACKOVERFLOW
728 bool
729
730config DEBUG_STACKOVERFLOW
731 bool "Check for stack overflows"
732 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
733 ---help---
734 Say Y here if you want to check for overflows of kernel, IRQ
Borislav Petkovedb0ec02015-01-25 19:50:34 +0100735 and exception stacks (if your architecture uses them). This
Dave Hansen0610c8a2013-07-01 13:04:43 -0700736 option will show detailed messages if free stack space drops
737 below a certain limit.
738
739 These kinds of bugs usually occur when call-chains in the
740 kernel get too deep, especially when interrupts are
741 involved.
742
743 Use this in cases where you see apparently random memory
744 corruption, especially if it appears in 'struct thread_info'
745
746 If in doubt, say "N".
747
Andrey Ryabinin0b24bec2015-02-13 14:39:17 -0800748source "lib/Kconfig.kasan"
749
Dave Hansen0610c8a2013-07-01 13:04:43 -0700750endmenu # "Memory Debugging"
751
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700752config ARCH_HAS_KCOV
753 bool
754 help
755 KCOV does not have any arch-specific code, but currently it is enabled
756 only for x86_64. KCOV requires testing on other archs, and most likely
757 disabling of instrumentation for some early boot code.
758
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900759config CC_HAS_SANCOV_TRACE_PC
760 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
761
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700762config KCOV
763 bool "Code coverage for fuzzing"
764 depends on ARCH_HAS_KCOV
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900765 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700766 select DEBUG_FS
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900767 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700768 help
769 KCOV exposes kernel code coverage information in a form suitable
770 for coverage-guided fuzzing (randomized testing).
771
772 If RANDOMIZE_BASE is enabled, PC values will not be stable across
773 different machines and across reboots. If you need stable PC values,
774 disable RANDOMIZE_BASE.
775
Andreas Platschek700199b02016-12-14 15:05:40 -0800776 For more details, see Documentation/dev-tools/kcov.rst.
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700777
Victor Chibotarud677a4d2017-11-17 15:30:50 -0800778config KCOV_ENABLE_COMPARISONS
779 bool "Enable comparison operands collection by KCOV"
780 depends on KCOV
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900781 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
Victor Chibotarud677a4d2017-11-17 15:30:50 -0800782 help
783 KCOV also exposes operands of every comparison in the instrumented
784 code along with operand sizes and PCs of the comparison instructions.
785 These operands can be used by fuzzing engines to improve the quality
786 of fuzzing coverage.
787
Vegard Nossuma4691de2016-08-02 14:07:30 -0700788config KCOV_INSTRUMENT_ALL
789 bool "Instrument all code by default"
790 depends on KCOV
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900791 default y
Vegard Nossuma4691de2016-08-02 14:07:30 -0700792 help
793 If you are doing generic system call fuzzing (like e.g. syzkaller),
794 then you will want to instrument the whole kernel and you should
795 say y here. If you are doing more targeted fuzzing (like e.g.
796 filesystem fuzzing with AFL) then you will want to enable coverage
797 for more specific subsets of files, and should say n here.
798
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799config DEBUG_SHIRQ
800 bool "Debug shared IRQ handlers"
Martin Schwidefsky0244ad02013-08-30 09:39:53 +0200801 depends on DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 help
803 Enable this to generate a spurious interrupt as soon as a shared
804 interrupt handler is registered, and just before one is deregistered.
805 Drivers ought to be able to handle interrupts coming in at those
806 points; some don't and need to be caught.
807
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700808menu "Debug Lockups and Hangs"
809
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810config LOCKUP_DETECTOR
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700811 bool
812
813config SOFTLOCKUP_DETECTOR
814 bool "Detect Soft Lockups"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 depends on DEBUG_KERNEL && !S390
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700816 select LOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817 help
818 Say Y here to enable the kernel to act as a watchdog to detect
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700819 soft lockups.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820
821 Softlockups are bugs that cause the kernel to loop in kernel
822 mode for more than 20 seconds, without giving other tasks a
823 chance to run. The current stack trace is displayed upon
824 detection and the system will stay locked up.
825
Randy Dunlap5f00ae02018-04-10 16:32:51 -0700826config BOOTPARAM_SOFTLOCKUP_PANIC
827 bool "Panic (Reboot) On Soft Lockups"
828 depends on SOFTLOCKUP_DETECTOR
829 help
830 Say Y here to enable the kernel to panic on "soft lockups",
831 which are bugs that cause the kernel to loop in kernel
832 mode for more than 20 seconds (configurable using the watchdog_thresh
833 sysctl), without giving other tasks a chance to run.
834
835 The panic can be used in combination with panic_timeout,
836 to cause the system to reboot automatically after a
837 lockup has been detected. This feature is useful for
838 high-availability systems that have uptime guarantees and
839 where a lockup must be resolved ASAP.
840
841 Say N if unsure.
842
843config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
844 int
845 depends on SOFTLOCKUP_DETECTOR
846 range 0 1
847 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
848 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
849
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700850config HARDLOCKUP_DETECTOR_PERF
851 bool
852 select SOFTLOCKUP_DETECTOR
853
854#
Thomas Gleixner7edaeb62017-08-15 09:50:13 +0200855# Enables a timestamp based low pass filter to compensate for perf based
856# hard lockup detection which runs too fast due to turbo modes.
857#
858config HARDLOCKUP_CHECK_TIMESTAMP
859 bool
860
861#
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700862# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
863# lockup detector rather than the perf based detector.
864#
865config HARDLOCKUP_DETECTOR
866 bool "Detect Hard Lockups"
867 depends on DEBUG_KERNEL && !S390
868 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
869 select LOCKUP_DETECTOR
870 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
871 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
872 help
873 Say Y here to enable the kernel to act as a watchdog to detect
874 hard lockups.
875
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 Hardlockups are bugs that cause the CPU to loop in kernel mode
877 for more than 10 seconds, without letting other interrupts have a
878 chance to run. The current stack trace is displayed upon detection
879 and the system will stay locked up.
880
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881config BOOTPARAM_HARDLOCKUP_PANIC
882 bool "Panic (Reboot) On Hard Lockups"
883 depends on HARDLOCKUP_DETECTOR
884 help
885 Say Y here to enable the kernel to panic on "hard lockups",
886 which are bugs that cause the kernel to loop in kernel
887 mode with interrupts disabled for more than 10 seconds (configurable
888 using the watchdog_thresh sysctl).
889
890 Say N if unsure.
891
892config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
893 int
894 depends on HARDLOCKUP_DETECTOR
895 range 0 1
896 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
897 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
898
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899config DETECT_HUNG_TASK
900 bool "Detect Hung Tasks"
901 depends on DEBUG_KERNEL
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700902 default SOFTLOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903 help
904 Say Y here to enable the kernel to detect "hung tasks",
905 which are bugs that cause the task to be stuck in
Vivien Didelot96b03ab2016-09-22 16:55:13 -0400906 uninterruptible "D" state indefinitely.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907
908 When a hung task is detected, the kernel will print the
909 current stack trace (which you should report), but the
910 task will stay in uninterruptible state. If lockdep is
911 enabled then all held locks will also be reported. This
912 feature has negligible overhead.
913
914config DEFAULT_HUNG_TASK_TIMEOUT
915 int "Default timeout for hung task detection (in seconds)"
916 depends on DETECT_HUNG_TASK
917 default 120
918 help
Ingo Molnar8637c092006-07-03 00:24:38 -0700919 This option controls the default timeout (in seconds) used
Linus Torvalds1da177e2005-04-16 15:20:36 -0700920 to determine when a task has become non-responsive and should
921 be considered hung.
922
923 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
924 sysctl or by writing a value to
925 /proc/sys/kernel/hung_task_timeout_secs.
926
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700927 A timeout of 0 disables the check. The default is two minutes.
928 Keeping the default should be fine in most cases.
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700929
930config BOOTPARAM_HUNG_TASK_PANIC
931 bool "Panic (Reboot) On Hung Tasks"
932 depends on DETECT_HUNG_TASK
933 help
934 Say Y here to enable the kernel to panic on "hung tasks",
935 which are bugs that cause the kernel to leave a task stuck
936 in uninterruptible "D" state.
937
938 The panic can be used in combination with panic_timeout,
Thomas Gleixner61a87122006-06-27 02:54:56 -0700939 to cause the system to reboot automatically after a
940 hung task has been detected. This feature is useful for
Roman Zippela1583d32006-06-27 02:55:00 -0700941 high-availability systems that have uptime guarantees and
Thomas Gleixner61a87122006-06-27 02:54:56 -0700942 where a hung tasks must be resolved ASAP.
943
944 Say N if unsure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100946config BOOTPARAM_HUNG_TASK_PANIC_VALUE
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947 int
948 depends on DETECT_HUNG_TASK
949 range 0 1
950 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
951 default 1 if BOOTPARAM_HUNG_TASK_PANIC
952
Tejun Heo82607adc2015-12-08 11:28:04 -0500953config WQ_WATCHDOG
954 bool "Detect Workqueue Stalls"
955 depends on DEBUG_KERNEL
956 help
957 Say Y here to enable stall detection on workqueues. If a
958 worker pool doesn't make forward progress on a pending work
959 item for over a given amount of time, 30s by default, a
960 warning message is printed along with dump of workqueue
961 state. This can be configured through kernel parameter
962 "workqueue.watchdog_thresh" and its sysfs counterpart.
963
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700964endmenu # "Debug lockups and hangs"
965
966config PANIC_ON_OOPS
967 bool "Panic on Oops"
968 help
969 Say Y here to enable the kernel to panic when it oopses. This
970 has the same effect as setting oops=panic on the kernel command
971 line.
972
973 This feature is useful to ensure that the kernel does not do
974 anything erroneous after an oops which could result in data
975 corruption or other issues.
976
977 Say N if unsure.
978
979config PANIC_ON_OOPS_VALUE
980 int
981 range 0 1
982 default 0 if !PANIC_ON_OOPS
983 default 1 if PANIC_ON_OOPS
984
Jason Baron5800dc32013-11-25 23:23:04 +0000985config PANIC_TIMEOUT
986 int "panic timeout"
987 default 0
988 help
989 Set the timeout value (in seconds) until a reboot occurs when the
990 the kernel panics. If n = 0, then we wait forever. A timeout
991 value n > 0 will wait n seconds before rebooting, while a timeout
992 value n < 0 will reboot immediately.
993
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994config SCHED_DEBUG
995 bool "Collect scheduler debugging info"
996 depends on DEBUG_KERNEL && PROC_FS
997 default y
998 help
999 If you say Y here, the /proc/sched_debug file will be provided
1000 that can help debug the scheduler. The runtime overhead of this
1001 option is minimal.
1002
Naveen N. Raof6db8342015-06-25 23:53:37 +05301003config SCHED_INFO
1004 bool
1005 default n
1006
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007config SCHEDSTATS
1008 bool "Collect scheduler statistics"
1009 depends on DEBUG_KERNEL && PROC_FS
Naveen N. Raof6db8342015-06-25 23:53:37 +05301010 select SCHED_INFO
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 help
1012 If you say Y here, additional code will be inserted into the
1013 scheduler and related routines to collect statistics about
1014 scheduler behavior and provide them in /proc/schedstat. These
1015 stats may be useful for both tuning and debugging the scheduler
1016 If you aren't debugging the scheduler or trying to tune a specific
1017 application, you can say N to avoid the very slight overhead
1018 this adds.
1019
Aaron Tomlin0d9e2632014-09-12 14:16:19 +01001020config SCHED_STACK_END_CHECK
1021 bool "Detect stack corruption on calls to schedule()"
1022 depends on DEBUG_KERNEL
1023 default n
1024 help
1025 This option checks for a stack overrun on calls to schedule().
1026 If the stack end location is found to be over written always panic as
1027 the content of the corrupted region can no longer be trusted.
1028 This is to ensure no erroneous behaviour occurs which could result in
1029 data corruption or a sporadic crash at a later stage once the region
1030 is examined. The runtime overhead introduced is minimal.
1031
John Stultz3c17ad12015-03-11 21:16:32 -07001032config DEBUG_TIMEKEEPING
1033 bool "Enable extra timekeeping sanity checking"
1034 help
1035 This option will enable additional timekeeping sanity checks
1036 which may be helpful when diagnosing issues where timekeeping
1037 problems are suspected.
1038
1039 This may include checks in the timekeeping hotpaths, so this
1040 option may have a (very small) performance impact to some
1041 workloads.
1042
1043 If unsure, say N.
1044
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045config DEBUG_PREEMPT
1046 bool "Debug preemptible kernel"
Kumar Gala01deab92009-10-16 07:21:39 +00001047 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048 default y
1049 help
1050 If you say Y here then the kernel will use a debug variant of the
1051 commonly used smp_processor_id() function and will print warnings
1052 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1053 will detect preemption count underflows.
1054
Dave Hansen9eade162013-07-01 13:04:47 -07001055menu "Lock Debugging (spinlocks, mutexes, etc...)"
1056
Waiman Longf07cbeb2018-03-30 17:27:59 -04001057config LOCK_DEBUGGING_SUPPORT
1058 bool
1059 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1060 default y
1061
Waiman Long19193bc2018-03-30 17:28:00 -04001062config PROVE_LOCKING
1063 bool "Lock debugging: prove locking correctness"
1064 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1065 select LOCKDEP
1066 select DEBUG_SPINLOCK
1067 select DEBUG_MUTEXES
1068 select DEBUG_RT_MUTEXES if RT_MUTEXES
1069 select DEBUG_RWSEMS if RWSEM_SPIN_ON_OWNER
1070 select DEBUG_WW_MUTEX_SLOWPATH
1071 select DEBUG_LOCK_ALLOC
1072 select TRACE_IRQFLAGS
1073 default n
1074 help
1075 This feature enables the kernel to prove that all locking
1076 that occurs in the kernel runtime is mathematically
1077 correct: that under no circumstance could an arbitrary (and
1078 not yet triggered) combination of observed locking
1079 sequences (on an arbitrary number of CPUs, running an
1080 arbitrary number of tasks and interrupt contexts) cause a
1081 deadlock.
1082
1083 In short, this feature enables the kernel to report locking
1084 related deadlocks before they actually occur.
1085
1086 The proof does not depend on how hard and complex a
1087 deadlock scenario would be to trigger: how many
1088 participant CPUs, tasks and irq-contexts would be needed
1089 for it to trigger. The proof also does not depend on
1090 timing: if a race and a resulting deadlock is possible
1091 theoretically (no matter how unlikely the race scenario
1092 is), it will be proven so and will immediately be
1093 reported by the kernel (once the event is observed that
1094 makes the deadlock theoretically possible).
1095
1096 If a deadlock is impossible (i.e. the locking rules, as
1097 observed by the kernel, are mathematically correct), the
1098 kernel reports nothing.
1099
1100 NOTE: this feature can also be enabled for rwlocks, mutexes
1101 and rwsems - in which case all dependencies between these
1102 different locking variants are observed and mapped too, and
1103 the proof of observed correctness is also maintained for an
1104 arbitrary combination of these separate locking variants.
1105
1106 For more details, see Documentation/locking/lockdep-design.txt.
1107
1108config LOCK_STAT
1109 bool "Lock usage statistics"
1110 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1111 select LOCKDEP
1112 select DEBUG_SPINLOCK
1113 select DEBUG_MUTEXES
1114 select DEBUG_RT_MUTEXES if RT_MUTEXES
1115 select DEBUG_LOCK_ALLOC
1116 default n
1117 help
1118 This feature enables tracking lock contention points
1119
1120 For more details, see Documentation/locking/lockstat.txt
1121
1122 This also enables lock events required by "perf lock",
1123 subcommand of perf.
1124 If you want to use "perf lock", you also need to turn on
1125 CONFIG_EVENT_TRACING.
1126
1127 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1128 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1129
Linus Torvalds1da177e2005-04-16 15:20:36 -07001130config DEBUG_RT_MUTEXES
1131 bool "RT Mutex debugging, deadlock detection"
1132 depends on DEBUG_KERNEL && RT_MUTEXES
1133 help
1134 This allows rt mutex semantics violations and rt mutex related
1135 deadlocks (lockups) to be detected and reported automatically.
1136
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001138 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +05301140 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141 help
1142 Say Y here and build SMP to catch missing spinlock initialization
1143 and certain other kinds of spinlock errors commonly made. This is
1144 best used in conjunction with the NMI watchdog so that spinlock
1145 deadlocks are also debuggable.
1146
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001147config DEBUG_MUTEXES
1148 bool "Mutex debugging: basic checks"
1149 depends on DEBUG_KERNEL
1150 help
1151 This feature allows mutex semantics violations to be detected and
1152 reported.
1153
Daniel Vetter23010022013-06-20 13:31:17 +02001154config DEBUG_WW_MUTEX_SLOWPATH
1155 bool "Wait/wound mutex debugging: Slowpath testing"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001156 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Daniel Vetter23010022013-06-20 13:31:17 +02001157 select DEBUG_LOCK_ALLOC
1158 select DEBUG_SPINLOCK
1159 select DEBUG_MUTEXES
1160 help
1161 This feature enables slowpath testing for w/w mutex users by
1162 injecting additional -EDEADLK wound/backoff cases. Together with
1163 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1164 will test all possible w/w mutex interface abuse with the
1165 exception of simply not acquiring all the required locks.
Rob Clark4d692372014-08-27 11:19:26 -04001166 Note that this feature can introduce significant overhead, so
1167 it really should not be enabled in a production or distro kernel,
1168 even a debug kernel. If you are a driver writer, enable it. If
1169 you are a distro, do not.
Daniel Vetter23010022013-06-20 13:31:17 +02001170
Waiman Long5149cba2018-03-30 17:27:58 -04001171config DEBUG_RWSEMS
1172 bool "RW Semaphore debugging: basic checks"
1173 depends on DEBUG_KERNEL && RWSEM_SPIN_ON_OWNER
1174 help
1175 This debugging feature allows mismatched rw semaphore locks and unlocks
1176 to be detected and reported.
1177
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001178config DEBUG_LOCK_ALLOC
1179 bool "Lock debugging: detect incorrect freeing of live locks"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001180 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001181 select DEBUG_SPINLOCK
1182 select DEBUG_MUTEXES
Peter Zijlstraf5694782016-09-19 12:15:37 +02001183 select DEBUG_RT_MUTEXES if RT_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001184 select LOCKDEP
1185 help
1186 This feature will check whether any held lock (spinlock, rwlock,
1187 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1188 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1189 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1190 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1191 held during task exit.
1192
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001193config LOCKDEP
1194 bool
Waiman Longf07cbeb2018-03-30 17:27:59 -04001195 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001196 select STACKTRACE
Stefan Agnerf9b58e82018-09-30 23:02:33 +01001197 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001198 select KALLSYMS
1199 select KALLSYMS_ALL
1200
Daniel Jordan395102d2017-04-10 11:50:52 -04001201config LOCKDEP_SMALL
1202 bool
1203
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001204config DEBUG_LOCKDEP
1205 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -07001206 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001207 help
1208 If you say Y here, the lock dependency engine will do
1209 additional runtime checks to debug itself, at the price
1210 of more runtime overhead.
1211
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001212config DEBUG_ATOMIC_SLEEP
1213 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +02001214 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 depends on DEBUG_KERNEL
Christoph Hellwig87a4c372018-07-31 13:39:32 +02001216 depends on !ARCH_NO_PREEMPT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217 help
1218 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001219 noisy if they are called inside atomic sections: when a spinlock is
1220 held, inside an rcu read side critical section, inside preempt disabled
1221 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222
Ingo Molnarcae2ed92006-07-03 00:24:48 -07001223config DEBUG_LOCKING_API_SELFTESTS
1224 bool "Locking API boot-time self-tests"
1225 depends on DEBUG_KERNEL
1226 help
1227 Say Y here if you want the kernel to run a short self-test during
1228 bootup. The self-test checks whether common types of locking bugs
1229 are detected by debugging mechanisms or not. (if you disable
1230 lock debugging then those bugs wont be detected of course.)
1231 The following locking APIs are covered: spinlocks, rwlocks,
1232 mutexes and rwsems.
1233
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001234config LOCK_TORTURE_TEST
1235 tristate "torture tests for locking"
1236 depends on DEBUG_KERNEL
1237 select TORTURE_TEST
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001238 help
1239 This option provides a kernel module that runs torture tests
1240 on kernel locking primitives. The kernel module may be built
1241 after the fact on the running kernel to be tested, if desired.
1242
1243 Say Y here if you want kernel locking-primitive torture tests
1244 to be built into the kernel.
1245 Say M if you want these torture tests to build as a module.
1246 Say N if you are unsure.
1247
Chris Wilsonf2a5fec2016-12-01 11:47:06 +00001248config WW_MUTEX_SELFTEST
1249 tristate "Wait/wound mutex selftests"
1250 help
1251 This option provides a kernel module that runs tests on the
1252 on the struct ww_mutex locking API.
1253
1254 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1255 with this test harness.
1256
1257 Say M if you want these self tests to build as a module.
1258 Say N if you are unsure.
1259
Dave Hansen9eade162013-07-01 13:04:47 -07001260endmenu # lock debugging
1261
1262config TRACE_IRQFLAGS
1263 bool
1264 help
1265 Enables hooks to interrupt enabling and disabling for
1266 either tracing or lock debugging.
1267
Ingo Molnar8637c092006-07-03 00:24:38 -07001268config STACKTRACE
Dave Jones0c38e1f2014-08-29 15:18:35 -07001269 bool "Stack backtrace support"
Ingo Molnar8637c092006-07-03 00:24:38 -07001270 depends on STACKTRACE_SUPPORT
Dave Jones0c38e1f2014-08-29 15:18:35 -07001271 help
1272 This option causes the kernel to create a /proc/pid/stack for
1273 every process, showing its current stack trace.
1274 It is also used by various kernel debugging features that require
1275 stack trace generation.
Ingo Molnar8637c092006-07-03 00:24:38 -07001276
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001277config WARN_ALL_UNSEEDED_RANDOM
1278 bool "Warn for all uses of unseeded randomness"
1279 default n
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001280 help
1281 Some parts of the kernel contain bugs relating to their use of
1282 cryptographically secure random numbers before it's actually possible
1283 to generate those numbers securely. This setting ensures that these
1284 flaws don't go unnoticed, by enabling a message, should this ever
1285 occur. This will allow people with obscure setups to know when things
1286 are going wrong, so that they might contact developers about fixing
1287 it.
1288
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001289 Unfortunately, on some models of some architectures getting
1290 a fully seeded CRNG is extremely difficult, and so this can
1291 result in dmesg getting spammed for a surprisingly long
1292 time. This is really bad from a security perspective, and
1293 so architecture maintainers really need to do what they can
1294 to get the CRNG seeded sooner after the system is booted.
Thibaut Sautereau4c5d1142018-09-04 15:46:23 -07001295 However, since users cannot do anything actionable to
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001296 address this, by default the kernel will issue only a single
1297 warning for the first use of unseeded randomness.
1298
1299 Say Y here if you want to receive warnings for all uses of
1300 unseeded randomness. This will be of use primarily for
Thibaut Sautereau4c5d1142018-09-04 15:46:23 -07001301 those developers interested in improving the security of
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001302 Linux kernels running on their architecture (or
1303 subarchitecture).
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001304
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305config DEBUG_KOBJECT
1306 bool "kobject debugging"
1307 depends on DEBUG_KERNEL
1308 help
1309 If you say Y here, some extra kobject debugging messages will be sent
Mike Rapoportaca52c32018-10-30 15:07:44 -07001310 to the syslog.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311
Russell Kingc817a672013-06-27 15:06:14 +01001312config DEBUG_KOBJECT_RELEASE
1313 bool "kobject release debugging"
Linus Torvalds2a999aa2013-10-29 08:33:36 -07001314 depends on DEBUG_OBJECTS_TIMERS
Russell Kingc817a672013-06-27 15:06:14 +01001315 help
1316 kobjects are reference counted objects. This means that their
1317 last reference count put is not predictable, and the kobject can
1318 live on past the point at which a driver decides to drop it's
1319 initial reference to the kobject gained on allocation. An
1320 example of this would be a struct device which has just been
1321 unregistered.
1322
1323 However, some buggy drivers assume that after such an operation,
1324 the memory backing the kobject can be immediately freed. This
1325 goes completely against the principles of a refcounted object.
1326
1327 If you say Y here, the kernel will delay the release of kobjects
1328 on the last reference count to improve the visibility of this
1329 kind of kobject release bug.
1330
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001331config HAVE_DEBUG_BUGVERBOSE
1332 bool
1333
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334config DEBUG_BUGVERBOSE
David Rientjes6a108a12011-01-20 14:44:16 -08001335 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001336 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
Alexey Dobriyan8420e7e2009-12-14 18:00:25 -08001337 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -07001338 help
1339 Say Y here to make BUG() panics output the file name and line number
1340 of the BUG call as well as the EIP and oops trace. This aids
1341 debugging but costs about 70-100K of memory.
1342
Dave Jones199a9af2006-09-29 01:59:00 -07001343config DEBUG_LIST
1344 bool "Debug linked list manipulation"
Arnd Bergmann4520bcb2016-08-26 17:42:00 +02001345 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
Dave Jones199a9af2006-09-29 01:59:00 -07001346 help
1347 Enable this to turn on extended checks in the linked-list
1348 walking routines.
1349
1350 If unsure, say N.
1351
Dan Streetmanb8cfff62014-06-04 16:11:54 -07001352config DEBUG_PI_LIST
1353 bool "Debug priority linked list manipulation"
1354 depends on DEBUG_KERNEL
1355 help
1356 Enable this to turn on extended checks in the priority-ordered
1357 linked-list (plist) walking routines. This checks the entire
1358 list multiple times during each manipulation.
1359
1360 If unsure, say N.
1361
Jens Axboed6ec0842007-10-22 20:01:06 +02001362config DEBUG_SG
1363 bool "Debug SG table operations"
1364 depends on DEBUG_KERNEL
1365 help
1366 Enable this to turn on checks on scatter-gather tables. This can
1367 help find problems with drivers that do not properly initialize
1368 their sg tables.
1369
1370 If unsure, say N.
1371
Arjan van de Ven1b2439d2008-08-15 15:29:38 -07001372config DEBUG_NOTIFIERS
1373 bool "Debug notifier call chains"
1374 depends on DEBUG_KERNEL
1375 help
1376 Enable this to turn on sanity checking for notifier call chains.
1377 This is most useful for kernel developers to make sure that
1378 modules properly unregister themselves from notifier chains.
1379 This is a relatively cheap check but if you care about maximum
1380 performance, say N.
1381
David Howellse0e81732009-09-02 09:13:40 +01001382config DEBUG_CREDENTIALS
1383 bool "Debug credential management"
1384 depends on DEBUG_KERNEL
1385 help
1386 Enable this to turn on some debug checking for credential
1387 management. The additional code keeps track of the number of
1388 pointers from task_structs to any given cred struct, and checks to
1389 see that this number never exceeds the usage count of the cred
1390 struct.
1391
1392 Furthermore, if SELinux is enabled, this also checks that the
1393 security pointer in the cred struct is never seen to be invalid.
1394
1395 If unsure, say N.
1396
Paul E. McKenney43a0a2a2017-05-17 09:19:44 -07001397source "kernel/rcu/Kconfig.debug"
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001398
Tejun Heof303fccb2016-02-09 17:59:38 -05001399config DEBUG_WQ_FORCE_RR_CPU
1400 bool "Force round-robin CPU selection for unbound work items"
1401 depends on DEBUG_KERNEL
1402 default n
1403 help
1404 Workqueue used to implicitly guarantee that work items queued
1405 without explicit CPU specified are put on the local CPU. This
1406 guarantee is no longer true and while local CPU is still
1407 preferred work items may be put on foreign CPUs. Kernel
1408 parameter "workqueue.debug_force_rr_cpu" is added to force
1409 round-robin CPU selection to flush out usages which depend on the
1410 now broken guarantee. This config option enables the debug
1411 feature by default. When enabled, memory and cache locality will
1412 be impacted.
1413
Tejun Heo870d6652008-08-25 19:47:25 +09001414config DEBUG_BLOCK_EXT_DEVT
1415 bool "Force extended block device numbers and spread them"
1416 depends on DEBUG_KERNEL
1417 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +02001418 default n
Tejun Heo870d6652008-08-25 19:47:25 +09001419 help
Tejun Heo0e11e342008-10-13 10:46:01 +02001420 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1421 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1422 YOU ARE DOING. Distros, please enable this and fix whatever
1423 is broken.
1424
Tejun Heo870d6652008-08-25 19:47:25 +09001425 Conventionally, block device numbers are allocated from
1426 predetermined contiguous area. However, extended block area
1427 may introduce non-contiguous block device numbers. This
1428 option forces most block device numbers to be allocated from
1429 the extended space and spreads them to discover kernel or
1430 userland code paths which assume predetermined contiguous
1431 device number allocation.
1432
Tejun Heo55dc7db2008-09-01 13:44:35 +02001433 Note that turning on this debug option shuffles all the
1434 device numbers for all IDE and SCSI devices including libata
1435 ones, so root partition specified using device number
1436 directly (via rdev or root=MAJ:MIN) won't work anymore.
1437 Textual device names (root=/dev/sdXn) will continue to work.
1438
Tejun Heo870d6652008-08-25 19:47:25 +09001439 Say N if you are unsure.
1440
Thomas Gleixner757c9892016-02-26 18:43:32 +00001441config CPU_HOTPLUG_STATE_CONTROL
1442 bool "Enable CPU hotplug state control"
1443 depends on DEBUG_KERNEL
1444 depends on HOTPLUG_CPU
1445 default n
1446 help
1447 Allows to write steps between "offline" and "online" to the CPUs
1448 sysfs target file so states can be stepped granular. This is a debug
1449 option for now as the hotplug machinery cannot be stopped and
1450 restarted at arbitrary points yet.
1451
1452 Say N if your are unsure.
1453
Akinobu Mita8d438282012-07-30 14:43:02 -07001454config NOTIFIER_ERROR_INJECTION
1455 tristate "Notifier error injection"
1456 depends on DEBUG_KERNEL
1457 select DEBUG_FS
1458 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001459 This option provides the ability to inject artificial errors to
Akinobu Mita8d438282012-07-30 14:43:02 -07001460 specified notifier chain callbacks. It is useful to test the error
1461 handling of notifier call chain failures.
1462
1463 Say N if unsure.
1464
Akinobu Mita048b9c32012-07-30 14:43:07 -07001465config PM_NOTIFIER_ERROR_INJECT
1466 tristate "PM notifier error injection module"
1467 depends on PM && NOTIFIER_ERROR_INJECTION
1468 default m if PM_DEBUG
1469 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001470 This option provides the ability to inject artificial errors to
Akinobu Mita048b9c32012-07-30 14:43:07 -07001471 PM notifier chain callbacks. It is controlled through debugfs
1472 interface /sys/kernel/debug/notifier-error-inject/pm
1473
1474 If the notifier call chain should be failed with some events
1475 notified, write the error code to "actions/<notifier event>/error".
1476
1477 Example: Inject PM suspend error (-12 = -ENOMEM)
1478
1479 # cd /sys/kernel/debug/notifier-error-inject/pm/
1480 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1481 # echo mem > /sys/power/state
1482 bash: echo: write error: Cannot allocate memory
1483
1484 To compile this code as a module, choose M here: the module will
1485 be called pm-notifier-error-inject.
1486
1487 If unsure, say N.
1488
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001489config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1490 tristate "OF reconfig notifier error injection module"
1491 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001492 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001493 This option provides the ability to inject artificial errors to
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001494 OF reconfig notifier chain callbacks. It is controlled
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001495 through debugfs interface under
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001496 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001497
1498 If the notifier call chain should be failed with some events
1499 notified, write the error code to "actions/<notifier event>/error".
1500
1501 To compile this code as a module, choose M here: the module will
Akinobu Mitae12a95f2013-04-30 15:28:49 -07001502 be called of-reconfig-notifier-error-inject.
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001503
1504 If unsure, say N.
1505
Nikolay Aleksandrov02fff962015-11-28 13:45:28 +01001506config NETDEV_NOTIFIER_ERROR_INJECT
1507 tristate "Netdev notifier error injection module"
1508 depends on NET && NOTIFIER_ERROR_INJECTION
1509 help
1510 This option provides the ability to inject artificial errors to
1511 netdevice notifier chain callbacks. It is controlled through debugfs
1512 interface /sys/kernel/debug/notifier-error-inject/netdev
1513
1514 If the notifier call chain should be failed with some events
1515 notified, write the error code to "actions/<notifier event>/error".
1516
1517 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1518
1519 # cd /sys/kernel/debug/notifier-error-inject/netdev
1520 # echo -22 > actions/NETDEV_CHANGEMTU/error
1521 # ip link set eth0 mtu 1024
1522 RTNETLINK answers: Invalid argument
1523
1524 To compile this code as a module, choose M here: the module will
1525 be called netdev-notifier-error-inject.
1526
1527 If unsure, say N.
1528
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001529config FUNCTION_ERROR_INJECTION
1530 def_bool y
1531 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1532
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001533config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001534 bool "Fault-injection framework"
1535 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001536 help
1537 Provide fault-injection framework.
1538 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001539
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001540config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001541 bool "Fault-injection capability for kmalloc"
1542 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001543 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001544 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001545 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001546
Akinobu Mita933e3122006-12-08 02:39:45 -08001547config FAIL_PAGE_ALLOC
1548 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001549 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001550 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001551 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001552
Akinobu Mitac17bb492006-12-08 02:39:46 -08001553config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001554 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001555 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001556 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001557 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001558
Jens Axboe581d4e22008-09-14 05:56:33 -07001559config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d01432010-07-21 16:05:53 +09001560 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001561 depends on FAULT_INJECTION && BLOCK
1562 help
1563 Provide fault-injection capability on end IO handling. This
1564 will make the block layer "forget" an interrupt as configured,
1565 thus exercising the error handling.
1566
1567 Only works with drivers that use the generic timeout handling,
1568 for others it wont do anything.
1569
Davidlohr Buesoab51fba2015-06-29 23:26:02 -07001570config FAIL_FUTEX
1571 bool "Fault-injection capability for futexes"
1572 select DEBUG_FS
1573 depends on FAULT_INJECTION && FUTEX
1574 help
1575 Provide fault-injection capability for futexes.
1576
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001577config FAULT_INJECTION_DEBUG_FS
1578 bool "Debugfs entries for fault-injection capabilities"
1579 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1580 help
1581 Enable configuration of fault-injection capabilities via debugfs.
1582
Masami Hiramatsu4b1a29a2018-01-13 02:56:03 +09001583config FAIL_FUNCTION
1584 bool "Fault-injection capability for functions"
1585 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1586 help
1587 Provide function-based fault-injection capability.
1588 This will allow you to override a specific function with a return
1589 with given return value. As a result, function caller will see
1590 an error value and have to handle it. This is useful to test the
1591 error handling in various subsystems.
1592
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001593config FAIL_MMC_REQUEST
1594 bool "Fault-injection capability for MMC IO"
1595 depends on FAULT_INJECTION_DEBUG_FS && MMC
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001596 help
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001597 Provide fault-injection capability for MMC IO.
1598 This will make the mmc core return data errors. This is
1599 useful to test the error handling in the mmc block device
1600 and to test how the mmc host driver handles retries from
1601 the block device.
Akinobu Mita1df49002007-02-20 13:57:56 -08001602
1603config FAULT_INJECTION_STACKTRACE_FILTER
1604 bool "stacktrace filter for fault-injection capabilities"
1605 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001606 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001607 select STACKTRACE
Stefan Agnerf9b58e82018-09-30 23:02:33 +01001608 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
Akinobu Mita1df49002007-02-20 13:57:56 -08001609 help
1610 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001611
Arjan van de Ven97455122008-01-25 21:08:34 +01001612config LATENCYTOP
1613 bool "Latency measuring infrastructure"
Randy Dunlap625fdca2010-08-12 12:31:21 -07001614 depends on DEBUG_KERNEL
1615 depends on STACKTRACE_SUPPORT
1616 depends on PROC_FS
Stefan Agnerf9b58e82018-09-30 23:02:33 +01001617 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
Arjan van de Ven97455122008-01-25 21:08:34 +01001618 select KALLSYMS
1619 select KALLSYMS_ALL
1620 select STACKTRACE
1621 select SCHEDSTATS
1622 select SCHED_DEBUG
Arjan van de Ven97455122008-01-25 21:08:34 +01001623 help
1624 Enable this option if you want to use the LatencyTOP tool
1625 to find out which userspace is blocking on what kernel operations.
1626
Masahiro Yamada8636a1f2018-12-11 20:01:04 +09001627source "kernel/trace/Kconfig"
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001628
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001629config PROVIDE_OHCI1394_DMA_INIT
1630 bool "Remote debugging over FireWire early on boot"
1631 depends on PCI && X86
1632 help
1633 If you want to debug problems which hang or crash the kernel early
1634 on boot and the crashing machine has a FireWire port, you can use
1635 this feature to remotely access the memory of the crashed machine
1636 over FireWire. This employs remote DMA as part of the OHCI1394
1637 specification which is now the standard for FireWire controllers.
1638
1639 With remote DMA, you can monitor the printk buffer remotely using
1640 firescope and access all memory below 4GB using fireproxy from gdb.
1641 Even controlling a kernel debugger is possible using remote DMA.
1642
1643 Usage:
1644
1645 If ohci1394_dma=early is used as boot parameter, it will initialize
1646 all OHCI1394 controllers which are found in the PCI config space.
1647
1648 As all changes to the FireWire bus such as enabling and disabling
1649 devices cause a bus reset and thereby disable remote DMA for all
1650 devices, be sure to have the cable plugged and FireWire enabled on
1651 the debugging host before booting the debug target for debugging.
1652
1653 This code (~1k) is freed after boot. By then, the firewire stack
1654 in charge of the OHCI-1394 controllers should be used instead.
1655
1656 See Documentation/debugging-via-ohci1394.txt for more information.
1657
1658config DMA_API_DEBUG
1659 bool "Enable debugging of DMA-API usage"
Christoph Hellwigf616ab52018-05-09 06:53:49 +02001660 select NEED_DMA_MAP_STATE
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001661 help
1662 Enable this option to debug the use of the DMA API by device drivers.
1663 With this option you will be able to detect common bugs in device
1664 drivers like double-freeing of DMA mappings or freeing mappings that
1665 were never allocated.
1666
1667 This also attempts to catch cases where a page owned by DMA is
1668 accessed by the cpu in a way that could cause data corruption. For
1669 example, this enables cow_user_page() to check that the source page is
1670 not undergoing DMA.
1671
1672 This option causes a performance degradation. Use only if you want to
1673 debug device drivers and dma interactions.
1674
1675 If unsure, say N.
1676
Robin Murphy78c47832018-05-21 12:35:13 +01001677config DMA_API_DEBUG_SG
1678 bool "Debug DMA scatter-gather usage"
1679 default y
1680 depends on DMA_API_DEBUG
1681 help
1682 Perform extra checking that callers of dma_map_sg() have respected the
1683 appropriate segment length/boundary limits for the given device when
1684 preparing DMA scatterlists.
1685
1686 This is particularly likely to have been overlooked in cases where the
1687 dma_map_sg() API is used for general bulk mapping of pages rather than
1688 preparing literal scatter-gather descriptors, where there is a risk of
1689 unexpected behaviour from DMA API implementations if the scatterlist
1690 is technically out-of-spec.
1691
1692 If unsure, say N.
1693
Vincent Legolld3deafa2018-02-06 15:38:38 -08001694menuconfig RUNTIME_TESTING_MENU
1695 bool "Runtime Testing"
Anders Roxell908009e82018-02-21 14:46:05 -08001696 def_bool y
Vincent Legolld3deafa2018-02-06 15:38:38 -08001697
1698if RUNTIME_TESTING_MENU
Dave Hansen881c5142013-07-01 13:04:44 -07001699
1700config LKDTM
1701 tristate "Linux Kernel Dump Test Tool Module"
1702 depends on DEBUG_FS
1703 depends on BLOCK
Dave Hansen881c5142013-07-01 13:04:44 -07001704 help
1705 This module enables testing of the different dumping mechanisms by
1706 inducing system failures at predefined crash points.
1707 If you don't need it: say N
1708 Choose M here to compile this code as a module. The module will be
1709 called lkdtm.
1710
1711 Documentation on how to use the module can be found in
1712 Documentation/fault-injection/provoke-crashes.txt
1713
1714config TEST_LIST_SORT
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001715 tristate "Linked list sorting test"
1716 depends on DEBUG_KERNEL || m
Dave Hansen881c5142013-07-01 13:04:44 -07001717 help
1718 Enable this to turn on 'list_sort()' function test. This test is
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001719 executed only once during system boot (so affects only boot time),
1720 or at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001721
1722 If unsure, say N.
1723
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001724config TEST_SORT
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001725 tristate "Array-based sort test"
1726 depends on DEBUG_KERNEL || m
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001727 help
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001728 This option enables the self-test function of 'sort()' at boot,
1729 or at module load time.
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001730
1731 If unsure, say N.
1732
Dave Hansen881c5142013-07-01 13:04:44 -07001733config KPROBES_SANITY_TEST
1734 bool "Kprobes sanity tests"
1735 depends on DEBUG_KERNEL
1736 depends on KPROBES
Dave Hansen881c5142013-07-01 13:04:44 -07001737 help
1738 This option provides for testing basic kprobes functionality on
Masami Hiramatsu5a6cf772018-06-20 01:05:07 +09001739 boot. Samples of kprobe and kretprobe are inserted and
Dave Hansen881c5142013-07-01 13:04:44 -07001740 verified for functionality.
1741
1742 Say N if you are unsure.
1743
1744config BACKTRACE_SELF_TEST
1745 tristate "Self test for the backtrace code"
1746 depends on DEBUG_KERNEL
Dave Hansen881c5142013-07-01 13:04:44 -07001747 help
1748 This option provides a kernel module that can be used to test
1749 the kernel stack backtrace code. This option is not useful
1750 for distributions or general kernels, but only for kernel
1751 developers working on architecture code.
1752
1753 Note that if you want to also test saved backtraces, you will
1754 have to enable STACKTRACE as well.
1755
1756 Say N if you are unsure.
1757
Michel Lespinasse910a7422012-10-08 16:30:39 -07001758config RBTREE_TEST
1759 tristate "Red-Black tree test"
Cody P Schafer7c993e12013-09-11 14:25:19 -07001760 depends on DEBUG_KERNEL
Michel Lespinasse910a7422012-10-08 16:30:39 -07001761 help
1762 A benchmark measuring the performance of the rbtree library.
1763 Also includes rbtree invariant checks.
1764
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001765config INTERVAL_TREE_TEST
1766 tristate "Interval tree test"
Davidlohr Bueso0f789b62017-07-10 15:51:43 -07001767 depends on DEBUG_KERNEL
Chris Wilsona88cc102014-03-17 12:21:54 +00001768 select INTERVAL_TREE
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001769 help
1770 A benchmark measuring the performance of the interval tree library
1771
Greg Thelen623fd802013-11-12 15:08:34 -08001772config PERCPU_TEST
1773 tristate "Per cpu operations test"
1774 depends on m && DEBUG_KERNEL
1775 help
1776 Enable this option to build test module which validates per-cpu
1777 operations.
1778
1779 If unsure, say N.
1780
Dave Hansen881c5142013-07-01 13:04:44 -07001781config ATOMIC64_SELFTEST
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001782 tristate "Perform an atomic64_t self-test"
Dave Hansen881c5142013-07-01 13:04:44 -07001783 help
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001784 Enable this option to test the atomic64_t functions at boot or
1785 at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001786
1787 If unsure, say N.
1788
1789config ASYNC_RAID6_TEST
1790 tristate "Self test for hardware accelerated raid6 recovery"
1791 depends on ASYNC_RAID6_RECOV
1792 select ASYNC_MEMCPY
1793 ---help---
1794 This is a one-shot self test that permutes through the
1795 recovery of all the possible two disk failure scenarios for a
1796 N-disk array. Recovery is performed with the asynchronous
1797 raid6 recovery routines, and will optionally use an offload
1798 engine if one is available.
1799
1800 If unsure, say N.
1801
Andy Shevchenko64d1d772015-02-12 15:02:21 -08001802config TEST_HEXDUMP
1803 tristate "Test functions located in the hexdump module at runtime"
1804
Dave Hansen881c5142013-07-01 13:04:44 -07001805config TEST_STRING_HELPERS
1806 tristate "Test functions located in the string_helpers module at runtime"
1807
1808config TEST_KSTRTOX
1809 tristate "Test kstrto*() family of functions at runtime"
1810
Rasmus Villemoes707cc722015-11-06 16:30:29 -08001811config TEST_PRINTF
1812 tristate "Test printf() family of functions at runtime"
1813
David Decotigny5fd003f2016-02-19 09:24:00 -05001814config TEST_BITMAP
1815 tristate "Test bitmap_*() family of functions at runtime"
David Decotigny5fd003f2016-02-19 09:24:00 -05001816 help
1817 Enable this option to test the bitmap functions at boot.
1818
1819 If unsure, say N.
1820
Johannes Berg0e2dc702018-06-20 08:58:30 +02001821config TEST_BITFIELD
1822 tristate "Test bitfield functions at runtime"
1823 help
1824 Enable this option to test the bitfield functions at boot.
1825
1826 If unsure, say N.
1827
Andy Shevchenkocfaff0e2016-05-30 17:40:41 +03001828config TEST_UUID
1829 tristate "Test functions located in the uuid module at runtime"
1830
Matthew Wilcoxad3d6c72017-11-07 14:57:46 -05001831config TEST_XARRAY
1832 tristate "Test the XArray code at runtime"
1833
Rasmus Villemoes455a35a2018-05-08 00:36:28 +02001834config TEST_OVERFLOW
1835 tristate "Test check_*_overflow() functions at runtime"
1836
Thomas Graf7e1e7762014-08-02 11:47:44 +02001837config TEST_RHASHTABLE
Geert Uytterhoeven9d6dbe12015-01-29 15:40:25 +01001838 tristate "Perform selftest on resizable hash table"
Thomas Graf7e1e7762014-08-02 11:47:44 +02001839 help
1840 Enable this option to test the rhashtable functions at boot.
1841
1842 If unsure, say N.
1843
George Spelvin468a9422016-05-26 22:11:51 -04001844config TEST_HASH
1845 tristate "Perform selftest on hash functions"
George Spelvin468a9422016-05-26 22:11:51 -04001846 help
Jason A. Donenfeld2c956a62017-01-08 13:54:00 +01001847 Enable this option to test the kernel's integer (<linux/hash.h>),
1848 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
1849 hash functions on boot (or module load).
George Spelvin468a9422016-05-26 22:11:51 -04001850
1851 This is intended to help people writing architecture-specific
1852 optimized versions. If unsure, say N.
1853
Matthew Wilcox8ab8ba32018-06-18 16:59:29 -04001854config TEST_IDA
1855 tristate "Perform selftest on IDA functions"
1856
Jiri Pirko44091d22017-02-03 10:29:06 +01001857config TEST_PARMAN
1858 tristate "Perform selftest on priority array manager"
Jiri Pirko44091d22017-02-03 10:29:06 +01001859 depends on PARMAN
1860 help
1861 Enable this option to test priority array manager on boot
1862 (or module load).
1863
1864 If unsure, say N.
1865
Valentin Rothberg8a6f0b42014-10-13 15:51:38 -07001866config TEST_LKM
Kees Cook93e9ef82014-01-23 15:54:37 -08001867 tristate "Test module loading with 'hello world' module"
Kees Cook93e9ef82014-01-23 15:54:37 -08001868 depends on m
1869 help
1870 This builds the "test_module" module that emits "Hello, world"
1871 on printk when loaded. It is designed to be used for basic
1872 evaluation of the module loading subsystem (for example when
1873 validating module verification). It lacks any extra dependencies,
1874 and will not normally be loaded by the system unless explicitly
1875 requested by name.
1876
1877 If unsure, say N.
1878
Kees Cook3e2a4c12014-01-23 15:54:38 -08001879config TEST_USER_COPY
1880 tristate "Test user/kernel boundary protections"
Kees Cook3e2a4c12014-01-23 15:54:38 -08001881 depends on m
1882 help
1883 This builds the "test_user_copy" module that runs sanity checks
1884 on the copy_to/from_user infrastructure, making sure basic
1885 user/kernel boundary testing is working. If it fails to load,
1886 a regression has been detected in the user/kernel memory boundary
1887 protections.
1888
1889 If unsure, say N.
1890
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001891config TEST_BPF
1892 tristate "Test BPF filter functionality"
Randy Dunlap98920ba2014-05-13 09:58:44 -07001893 depends on m && NET
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001894 help
1895 This builds the "test_bpf" module that runs various test vectors
1896 against the BPF interpreter or BPF JIT compiler depending on the
1897 current setting. This is in particular useful for BPF JIT compiler
1898 development, but also to run regression tests against changes in
Alexei Starovoitov3c731eb2014-09-26 00:17:07 -07001899 the interpreter code. It also enables test stubs for eBPF maps and
1900 verifier used by user space verifier testsuite.
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001901
1902 If unsure, say N.
1903
Yury Norovdceeb3e2018-02-06 15:38:27 -08001904config FIND_BIT_BENCHMARK
Yury Norov4441fca2017-11-17 15:28:31 -08001905 tristate "Test find_bit functions"
Yury Norov4441fca2017-11-17 15:28:31 -08001906 help
1907 This builds the "test_find_bit" module that measure find_*_bit()
1908 functions performance.
1909
1910 If unsure, say N.
1911
Kees Cook0a8adf52014-07-14 14:38:12 -07001912config TEST_FIRMWARE
1913 tristate "Test firmware loading via userspace interface"
Kees Cook0a8adf52014-07-14 14:38:12 -07001914 depends on FW_LOADER
1915 help
1916 This builds the "test_firmware" module that creates a userspace
1917 interface for testing firmware loading. This can be used to
1918 control the triggering of firmware loading without needing an
1919 actual firmware-using device. The contents can be rechecked by
1920 userspace.
1921
1922 If unsure, say N.
1923
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07001924config TEST_SYSCTL
1925 tristate "sysctl test driver"
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07001926 depends on PROC_SYSCTL
1927 help
1928 This builds the "test_sysctl" module. This driver enables to test the
1929 proc sysctl interfaces available to drivers safely without affecting
1930 production knobs which might alter system functionality.
1931
1932 If unsure, say N.
1933
David Rileye704f932014-06-16 14:58:32 -07001934config TEST_UDELAY
1935 tristate "udelay test driver"
David Rileye704f932014-06-16 14:58:32 -07001936 help
1937 This builds the "udelay_test" module that helps to make sure
1938 that udelay() is working properly.
1939
1940 If unsure, say N.
1941
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02001942config TEST_STATIC_KEYS
1943 tristate "Test static keys"
Jason Baron579e1ac2015-07-30 03:59:44 +00001944 depends on m
1945 help
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02001946 Test the static key interfaces.
Jason Baron579e1ac2015-07-30 03:59:44 +00001947
1948 If unsure, say N.
1949
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07001950config TEST_KMOD
1951 tristate "kmod stress tester"
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07001952 depends on m
1953 depends on BLOCK && (64BIT || LBDAF) # for XFS, BTRFS
1954 depends on NETDEVICES && NET_CORE && INET # for TUN
1955 select TEST_LKM
1956 select XFS_FS
1957 select TUN
1958 select BTRFS_FS
1959 help
1960 Test the kernel's module loading mechanism: kmod. kmod implements
1961 support to load modules using the Linux kernel's usermode helper.
1962 This test provides a series of tests against kmod.
1963
1964 Although technically you can either build test_kmod as a module or
1965 into the kernel we disallow building it into the kernel since
1966 it stress tests request_module() and this will very likely cause
1967 some issues by taking over precious threads available from other
1968 module load requests, ultimately this could be fatal.
1969
1970 To run tests run:
1971
1972 tools/testing/selftests/kmod/kmod.sh --help
1973
1974 If unsure, say N.
1975
Florian Fainellie4dace32017-09-08 16:15:31 -07001976config TEST_DEBUG_VIRTUAL
1977 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
1978 depends on DEBUG_VIRTUAL
1979 help
1980 Test the kernel's ability to detect incorrect calls to
1981 virt_to_phys() done against the non-linear part of the
1982 kernel's virtual address map.
1983
1984 If unsure, say N.
1985
Alexander Shishkince76d932018-10-05 15:43:05 +03001986config TEST_MEMCAT_P
1987 tristate "Test memcat_p() helper function"
1988 help
1989 Test the memcat_p() helper for correctly merging two
1990 pointer arrays together.
1991
1992 If unsure, say N.
1993
Jiri Pirko0a020d42018-11-14 08:22:28 +00001994config TEST_OBJAGG
1995 tristate "Perform selftest on object aggreration manager"
1996 default n
1997 depends on OBJAGG
1998 help
1999 Enable this option to test object aggregation manager on boot
2000 (or module load).
2001
2002 If unsure, say N.
2003
Vincent Legolld3deafa2018-02-06 15:38:38 -08002004endif # RUNTIME_TESTING_MENU
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002005
2006config MEMTEST
2007 bool "Memtest"
Randy Dunlapcc3fa842017-10-13 15:57:33 -07002008 ---help---
2009 This option adds a kernel parameter 'memtest', which allows memtest
2010 to be set.
2011 memtest=0, mean disabled; -- default
2012 memtest=1, mean do 1 test pattern;
2013 ...
2014 memtest=17, mean do 17 test patterns.
2015 If you are unsure how to answer this question, answer N.
2016
2017config BUG_ON_DATA_CORRUPTION
2018 bool "Trigger a BUG when data corruption is detected"
2019 select DEBUG_LIST
2020 help
2021 Select this option if the kernel should BUG when it encounters
2022 data corruption in kernel memory structures when they get checked
2023 for validity.
2024
2025 If unsure, say N.
Florian Fainellie4dace32017-09-08 16:15:31 -07002026
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07002027source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02002028
2029source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02002030
Andrey Ryabininc6d30852016-01-20 15:00:55 -08002031source "lib/Kconfig.ubsan"
2032
Dan Williams21266be2015-11-19 18:19:29 -08002033config ARCH_HAS_DEVMEM_IS_ALLOWED
2034 bool
2035
2036config STRICT_DEVMEM
2037 bool "Filter access to /dev/mem"
Dave Young6b2a65c2016-12-12 16:46:14 -08002038 depends on MMU && DEVMEM
Dan Williams21266be2015-11-19 18:19:29 -08002039 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
Arnd Bergmanna687a532018-03-07 23:30:54 +01002040 default y if PPC || X86 || ARM64
Dan Williams21266be2015-11-19 18:19:29 -08002041 ---help---
2042 If this option is disabled, you allow userspace (root) access to all
2043 of memory, including kernel and userspace memory. Accidental
2044 access to this is obviously disastrous, but specific access can
2045 be used by people debugging the kernel. Note that with PAT support
2046 enabled, even in this case there are restrictions on /dev/mem
2047 use due to the cache aliasing requirements.
2048
Dan Williams90a545e2015-11-23 15:49:03 -08002049 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
2050 file only allows userspace access to PCI space and the BIOS code and
2051 data regions. This is sufficient for dosemu and X and all common
2052 users of /dev/mem.
2053
2054 If in doubt, say Y.
2055
2056config IO_STRICT_DEVMEM
2057 bool "Filter I/O access to /dev/mem"
2058 depends on STRICT_DEVMEM
Dan Williams90a545e2015-11-23 15:49:03 -08002059 ---help---
2060 If this option is disabled, you allow userspace (root) access to all
2061 io-memory regardless of whether a driver is actively using that
2062 range. Accidental access to this is obviously disastrous, but
2063 specific access can be used by people debugging kernel drivers.
2064
Dan Williams21266be2015-11-19 18:19:29 -08002065 If this option is switched on, the /dev/mem file only allows
Dan Williams90a545e2015-11-23 15:49:03 -08002066 userspace access to *idle* io-memory ranges (see /proc/iomem) This
2067 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
2068 if the driver using a given range cannot be disabled.
Dan Williams21266be2015-11-19 18:19:29 -08002069
2070 If in doubt, say Y.
Christoph Hellwig06ec64b2018-07-31 13:39:31 +02002071
2072source "arch/$(SRCARCH)/Kconfig.debug"
2073
2074endmenu # Kernel hacking