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Dave Hansen604ff0d2013-07-01 13:04:49 -07001menu "printk and dmesg options"
Linus Torvalds1da177e2005-04-16 15:20:36 -07002
3config PRINTK_TIME
4 bool "Show timing information on printks"
Randy Dunlapd3b8b6e2006-12-06 20:36:38 -08005 depends on PRINTK
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 help
Kay Sievers649e6ee2012-05-10 04:30:45 +02007 Selecting this option causes time stamps of the printk()
8 messages to be added to the output of the syslog() system
9 call and at the console.
10
11 The timestamp is always recorded internally, and exported
12 to /dev/kmsg. This flag just specifies if the timestamp should
13 be included, not that the timestamp is recorded.
14
15 The behavior is also controlled by the kernel command line
Mauro Carvalho Chehab8c27ceff32016-10-18 10:12:27 -020016 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
Linus Torvalds1da177e2005-04-16 15:20:36 -070017
Olof Johanssona8cfdc62016-12-12 16:45:56 -080018config CONSOLE_LOGLEVEL_DEFAULT
19 int "Default console loglevel (1-15)"
20 range 1 15
21 default "7"
22 help
23 Default loglevel to determine what will be printed on the console.
24
25 Setting a default here is equivalent to passing in loglevel=<x> in
26 the kernel bootargs. loglevel=<x> continues to override whatever
27 value is specified here as well.
28
Borislav Petkov50f4d9b2016-12-19 16:23:15 -080029 Note: This does not affect the log level of un-prefixed printk()
Olof Johanssona8cfdc62016-12-12 16:45:56 -080030 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
31 option.
32
Alex Elder42a9dc02014-08-06 16:09:01 -070033config MESSAGE_LOGLEVEL_DEFAULT
Mandeep Singh Baines5af5bcb2011-03-22 16:34:23 -070034 int "Default message log level (1-7)"
35 range 1 7
36 default "4"
37 help
38 Default log level for printk statements with no specified priority.
39
40 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
41 that are auditing their logs closely may want to set it to a lower
42 priority.
43
Olof Johanssona8cfdc62016-12-12 16:45:56 -080044 Note: This does not affect what message level gets printed on the console
45 by default. To change that, use loglevel=<x> in the kernel bootargs,
46 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
47
Dave Hansen604ff0d2013-07-01 13:04:49 -070048config BOOT_PRINTK_DELAY
49 bool "Delay each boot printk message by N milliseconds"
50 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
51 help
52 This build option allows you to read kernel boot messages
53 by inserting a short delay after each one. The delay is
54 specified in milliseconds on the kernel command line,
55 using "boot_delay=N".
56
57 It is likely that you would also need to use "lpj=M" to preset
58 the "loops per jiffie" value.
59 See a previous boot log for the "lpj" value to use for your
60 system, and then set "lpj=M" before setting "boot_delay=N".
61 NOTE: Using this option may adversely affect SMP systems.
62 I.e., processors other than the first one may not boot up.
63 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
64 what it believes to be lockup conditions.
65
66config DYNAMIC_DEBUG
67 bool "Enable dynamic printk() support"
68 default n
69 depends on PRINTK
70 depends on DEBUG_FS
71 help
72
73 Compiles debug level messages into the kernel, which would not
74 otherwise be available at runtime. These messages can then be
75 enabled/disabled based on various levels of scope - per source file,
76 function, module, format string, and line number. This mechanism
77 implicitly compiles in all pr_debug() and dev_dbg() calls, which
78 enlarges the kernel text size by about 2%.
79
80 If a source file is compiled with DEBUG flag set, any
81 pr_debug() calls in it are enabled by default, but can be
82 disabled at runtime as below. Note that DEBUG flag is
83 turned on by many CONFIG_*DEBUG* options.
84
85 Usage:
86
87 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
88 which is contained in the 'debugfs' filesystem. Thus, the debugfs
89 filesystem must first be mounted before making use of this feature.
90 We refer the control file as: <debugfs>/dynamic_debug/control. This
91 file contains a list of the debug statements that can be enabled. The
92 format for each line of the file is:
93
94 filename:lineno [module]function flags format
95
96 filename : source file of the debug statement
97 lineno : line number of the debug statement
98 module : module that contains the debug statement
99 function : function that contains the debug statement
100 flags : '=p' means the line is turned 'on' for printing
101 format : the format used for the debug statement
102
103 From a live system:
104
105 nullarbor:~ # cat <debugfs>/dynamic_debug/control
106 # filename:lineno [module]function flags format
107 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
108 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
109 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
110
111 Example usage:
112
113 // enable the message at line 1603 of file svcsock.c
114 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
115 <debugfs>/dynamic_debug/control
116
117 // enable all the messages in file svcsock.c
118 nullarbor:~ # echo -n 'file svcsock.c +p' >
119 <debugfs>/dynamic_debug/control
120
121 // enable all the messages in the NFS server module
122 nullarbor:~ # echo -n 'module nfsd +p' >
123 <debugfs>/dynamic_debug/control
124
125 // enable all 12 messages in the function svc_process()
126 nullarbor:~ # echo -n 'func svc_process +p' >
127 <debugfs>/dynamic_debug/control
128
129 // disable all 12 messages in the function svc_process()
130 nullarbor:~ # echo -n 'func svc_process -p' >
131 <debugfs>/dynamic_debug/control
132
Hans Holmbergf8998c22017-03-16 09:37:32 +0100133 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
134 information.
Dave Hansen604ff0d2013-07-01 13:04:49 -0700135
136endmenu # "printk and dmesg options"
137
Dave Hansen6dfc0662013-07-01 13:04:46 -0700138menu "Compile-time checks and compiler options"
139
140config DEBUG_INFO
141 bool "Compile the kernel with debug info"
Linus Torvalds12b13832014-02-04 12:20:01 -0800142 depends on DEBUG_KERNEL && !COMPILE_TEST
Dave Hansen6dfc0662013-07-01 13:04:46 -0700143 help
144 If you say Y here the resulting kernel image will include
145 debugging info resulting in a larger kernel image.
146 This adds debug symbols to the kernel and modules (gcc -g), and
147 is needed if you intend to use kernel crashdump or binary object
148 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
149 Say Y here only if you plan to debug the kernel.
150
151 If unsure, say N.
152
153config DEBUG_INFO_REDUCED
154 bool "Reduce debugging information"
155 depends on DEBUG_INFO
156 help
157 If you say Y here gcc is instructed to generate less debugging
158 information for structure types. This means that tools that
159 need full debugging information (like kgdb or systemtap) won't
160 be happy. But if you merely need debugging information to
161 resolve line numbers there is no loss. Advantage is that
162 build directory object sizes shrink dramatically over a full
163 DEBUG_INFO build and compile times are reduced too.
164 Only works with newer gcc versions.
165
Andi Kleen866ced92014-07-30 20:50:18 +0200166config DEBUG_INFO_SPLIT
167 bool "Produce split debuginfo in .dwo files"
Arnd Bergmanna687a532018-03-07 23:30:54 +0100168 depends on DEBUG_INFO
Andi Kleen866ced92014-07-30 20:50:18 +0200169 help
170 Generate debug info into separate .dwo files. This significantly
171 reduces the build directory size for builds with DEBUG_INFO,
172 because it stores the information only once on disk in .dwo
173 files instead of multiple times in object files and executables.
174 In addition the debug information is also compressed.
175
176 Requires recent gcc (4.7+) and recent gdb/binutils.
177 Any tool that packages or reads debug information would need
178 to know about the .dwo files and include them.
179 Incompatible with older versions of ccache.
180
Andi Kleenbfaf2dd2014-07-30 20:50:19 +0200181config DEBUG_INFO_DWARF4
182 bool "Generate dwarf4 debuginfo"
183 depends on DEBUG_INFO
184 help
185 Generate dwarf4 debug info. This requires recent versions
186 of gcc and gdb. It makes the debug information larger.
187 But it significantly improves the success of resolving
188 variables in gdb on optimized code.
189
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800190config GDB_SCRIPTS
191 bool "Provide GDB scripts for kernel debugging"
192 depends on DEBUG_INFO
193 help
194 This creates the required links to GDB helper scripts in the
195 build directory. If you load vmlinux into gdb, the helper
196 scripts will be automatically imported by gdb as well, and
197 additional functions are available to analyze a Linux kernel
Andreas Platschek700199b02016-12-14 15:05:40 -0800198 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
199 for further details.
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800200
Jeff Garzikde488442007-10-25 04:06:13 -0400201config ENABLE_WARN_DEPRECATED
202 bool "Enable __deprecated logic"
203 default y
204 help
205 Enable the __deprecated logic in the kernel build.
206 Disable this to suppress the "warning: 'foo' is deprecated
207 (declared at kernel/power/somefile.c:1234)" messages.
208
Andrew Mortoncebc04b2006-08-14 22:43:18 -0700209config ENABLE_MUST_CHECK
210 bool "Enable __must_check logic"
211 default y
212 help
213 Enable the __must_check logic in the kernel build. Disable this to
214 suppress the "warning: ignoring return value of 'foo', declared with
215 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216
Andi Kleen35bb5b12008-02-22 15:15:03 +0100217config FRAME_WARN
218 int "Warn for stack frames larger than (needs gcc 4.4)"
219 range 0 8192
Arnd Bergmanne7c52b82018-02-06 15:41:41 -0800220 default 3072 if KASAN_EXTRA
Kees Cook0e07f662016-10-27 17:46:41 -0700221 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
Helge Deller432654d2017-09-11 21:41:43 +0200222 default 1280 if (!64BIT && PARISC)
223 default 1024 if (!64BIT && !PARISC)
Andi Kleen35bb5b12008-02-22 15:15:03 +0100224 default 2048 if 64BIT
225 help
226 Tell gcc to warn at build time for stack frames larger than this.
227 Setting this too low will cause a lot of warnings.
228 Setting it to 0 disables the warning.
229 Requires gcc 4.4
230
Randy Dunlap99657c72009-09-18 12:49:22 -0700231config STRIP_ASM_SYMS
232 bool "Strip assembler-generated symbols during link"
233 default n
234 help
235 Strip internal assembler-generated symbols during a link (symbols
236 that look like '.Lxxx') so they don't pollute the output of
237 get_wchan() and suchlike.
238
Andi Kleen1873e872012-03-28 11:51:18 -0700239config READABLE_ASM
240 bool "Generate readable assembler code"
241 depends on DEBUG_KERNEL
242 help
243 Disable some compiler optimizations that tend to generate human unreadable
244 assembler output. This may make the kernel slightly slower, but it helps
245 to keep kernel developers who have to stare a lot at assembler listings
246 sane.
247
Arjan van de Venf71d20e2006-06-28 04:26:45 -0700248config UNUSED_SYMBOLS
249 bool "Enable unused/obsolete exported symbols"
250 default y if X86
251 help
252 Unused but exported symbols make the kernel needlessly bigger. For
253 that reason most of these unused exports will soon be removed. This
254 option is provided temporarily to provide a transition period in case
255 some external kernel module needs one of these symbols anyway. If you
256 encounter such a case in your module, consider if you are actually
257 using the right API. (rationale: since nobody in the kernel is using
258 this in a module, there is a pretty good chance it's actually the
259 wrong interface to use). If you really need the symbol, please send a
260 mail to the linux kernel mailing list mentioning the symbol and why
261 you really need it, and what the merge plan to the mainline kernel for
262 your module is.
263
Joonsoo Kim48c96a32014-12-12 16:56:01 -0800264config PAGE_OWNER
265 bool "Track page owner"
266 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
267 select DEBUG_FS
268 select STACKTRACE
Joonsoo Kimf2ca0b52016-07-26 15:23:55 -0700269 select STACKDEPOT
Joonsoo Kim48c96a32014-12-12 16:56:01 -0800270 select PAGE_EXTENSION
271 help
272 This keeps track of what call chain is the owner of a page, may
273 help to find bare alloc_page(s) leaks. Even if you include this
274 feature on your build, it is disabled in default. You should pass
275 "page_owner=on" to boot parameter in order to enable it. Eats
276 a fair amount of memory if enabled. See tools/vm/page_owner_sort.c
277 for user-space helper.
278
279 If unsure, say N.
280
Don Mullisbf4735a2006-12-10 02:18:37 -0800281config DEBUG_FS
282 bool "Debug Filesystem"
Don Mullisbf4735a2006-12-10 02:18:37 -0800283 help
284 debugfs is a virtual file system that kernel developers use to put
285 debugging files into. Enable this option to be able to read and
286 write to these files.
287
Robert P. J. Dayff543332008-05-20 00:06:00 +0200288 For detailed documentation on the debugfs API, see
Mauro Carvalho Chehabe1b4fc72017-05-14 12:04:55 -0300289 Documentation/filesystems/.
Robert P. J. Dayff543332008-05-20 00:06:00 +0200290
Don Mullisbf4735a2006-12-10 02:18:37 -0800291 If unsure, say N.
292
293config HEADERS_CHECK
294 bool "Run 'make headers_check' when building vmlinux"
295 depends on !UML
296 help
297 This option will extract the user-visible kernel headers whenever
298 building the kernel, and will run basic sanity checks on them to
299 ensure that exported files do not attempt to include files which
300 were not exported, etc.
301
302 If you're making modifications to header files which are
303 relevant for userspace, say 'Y', and check the headers
304 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
305 your build tree), to make sure they're suitable.
306
Sam Ravnborg91341d42008-01-21 21:31:44 +0100307config DEBUG_SECTION_MISMATCH
308 bool "Enable full Section mismatch analysis"
Sam Ravnborg91341d42008-01-21 21:31:44 +0100309 help
310 The section mismatch analysis checks if there are illegal
311 references from one section to another section.
Michael Wittene809ab02011-04-17 04:08:48 +0000312 During linktime or runtime, some sections are dropped;
313 any use of code/data previously in these sections would
Sam Ravnborg91341d42008-01-21 21:31:44 +0100314 most likely result in an oops.
Michael Wittene809ab02011-04-17 04:08:48 +0000315 In the code, functions and variables are annotated with
Paul Gortmaker0db06282013-06-19 14:53:51 -0400316 __init,, etc. (see the full list in include/linux/init.h),
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100317 which results in the code/data being placed in specific sections.
Michael Wittene809ab02011-04-17 04:08:48 +0000318 The section mismatch analysis is always performed after a full
319 kernel build, and enabling this option causes the following
320 additional steps to occur:
321 - Add the option -fno-inline-functions-called-once to gcc commands.
322 When inlining a function annotated with __init in a non-init
323 function, we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100324 the analysis would not catch the illegal reference.
Michael Wittene809ab02011-04-17 04:08:48 +0000325 This option tells gcc to inline less (but it does result in
326 a larger kernel).
Nicholas Pigginf49821e2018-02-11 00:25:04 +1000327 - Run the section mismatch analysis for each module/built-in.a file.
Michael Wittene809ab02011-04-17 04:08:48 +0000328 When we run the section mismatch analysis on vmlinux.o, we
Uwe Kleine-König67797b92016-09-09 10:04:58 +0200329 lose valuable information about where the mismatch was
Sam Ravnborg91341d42008-01-21 21:31:44 +0100330 introduced.
Nicholas Pigginf49821e2018-02-11 00:25:04 +1000331 Running the analysis for each module/built-in.a file
Michael Wittene809ab02011-04-17 04:08:48 +0000332 tells where the mismatch happens much closer to the
333 source. The drawback is that the same mismatch is
334 reported at least twice.
335 - Enable verbose reporting from modpost in order to help resolve
336 the section mismatches that are reported.
Sam Ravnborg91341d42008-01-21 21:31:44 +0100337
Nicolas Boichat47490ec2015-10-06 09:44:42 +1030338config SECTION_MISMATCH_WARN_ONLY
339 bool "Make section mismatch errors non-fatal"
340 default y
341 help
342 If you say N here, the build process will fail if there are any
343 section mismatch, instead of just throwing warnings.
344
345 If unsure, say Y.
346
Dave Hansen6dfc0662013-07-01 13:04:46 -0700347#
348# Select this config option from the architecture Kconfig, if it
349# is preferred to always offer frame pointers as a config
350# option on the architecture (regardless of KERNEL_DEBUG):
351#
352config ARCH_WANT_FRAME_POINTERS
353 bool
Dave Hansen6dfc0662013-07-01 13:04:46 -0700354
355config FRAME_POINTER
356 bool "Compile the kernel with frame pointers"
Arnd Bergmanna687a532018-03-07 23:30:54 +0100357 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
Dave Hansen6dfc0662013-07-01 13:04:46 -0700358 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
359 help
360 If you say Y here the resulting kernel image will be slightly
361 larger and slower, but it gives very useful debugging information
362 in case of kernel bugs. (precise oopses/stacktraces/warnings)
363
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600364config STACK_VALIDATION
365 bool "Compile-time stack metadata validation"
366 depends on HAVE_STACK_VALIDATION
367 default n
368 help
369 Add compile-time checks to validate stack metadata, including frame
370 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
371 that runtime stack traces are more reliable.
372
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500373 This is also a prerequisite for generation of ORC unwind data, which
Josh Poimboeuf11af8472017-10-13 15:02:00 -0500374 is needed for CONFIG_UNWINDER_ORC.
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500375
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600376 For more information, see
377 tools/objtool/Documentation/stack-validation.txt.
378
Dave Hansen6dfc0662013-07-01 13:04:46 -0700379config DEBUG_FORCE_WEAK_PER_CPU
380 bool "Force weak per-cpu definitions"
381 depends on DEBUG_KERNEL
382 help
383 s390 and alpha require percpu variables in modules to be
384 defined weak to work around addressing range issue which
385 puts the following two restrictions on percpu variable
386 definitions.
387
388 1. percpu symbols must be unique whether static or not
389 2. percpu variables can't be defined inside a function
390
391 To ensure that generic code follows the above rules, this
392 option forces all percpu variables to be defined as weak.
393
394endmenu # "Compiler options"
395
396config MAGIC_SYSRQ
397 bool "Magic SysRq key"
398 depends on !UML
399 help
400 If you say Y here, you will have some control over the system even
401 if the system crashes for example during kernel debugging (e.g., you
402 will be able to flush the buffer cache to disk, reboot the system
403 immediately or dump some status information). This is accomplished
404 by pressing various keys while holding SysRq (Alt+PrintScreen). It
405 also works on a serial console (on PC hardware at least), if you
406 send a BREAK and then within 5 seconds a command keypress. The
Hans Holmbergf8998c22017-03-16 09:37:32 +0100407 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
408 Don't say Y unless you really know what this hack does.
Dave Hansen6dfc0662013-07-01 13:04:46 -0700409
Ben Hutchings8eaede42013-10-07 01:05:46 +0100410config MAGIC_SYSRQ_DEFAULT_ENABLE
411 hex "Enable magic SysRq key functions by default"
412 depends on MAGIC_SYSRQ
413 default 0x1
414 help
415 Specifies which SysRq key functions are enabled by default.
416 This may be set to 1 or 0 to enable or disable them all, or
Hans Holmbergf8998c22017-03-16 09:37:32 +0100417 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
Ben Hutchings8eaede42013-10-07 01:05:46 +0100418
Felix Fietkau732dbf32016-12-22 08:31:34 +0100419config MAGIC_SYSRQ_SERIAL
420 bool "Enable magic SysRq key over serial"
421 depends on MAGIC_SYSRQ
422 default y
423 help
424 Many embedded boards have a disconnected TTL level serial which can
425 generate some garbage that can lead to spurious false sysrq detects.
426 This option allows you to decide whether you want to enable the
427 magic SysRq key.
428
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800429config DEBUG_KERNEL
430 bool "Kernel debugging"
431 help
432 Say Y here if you are developing drivers or trying to debug and
433 identify kernel problems.
434
Dave Hansen0610c8a2013-07-01 13:04:43 -0700435menu "Memory Debugging"
David Woodhousea304e1b2007-02-12 00:52:00 -0800436
Dave Hansen0610c8a2013-07-01 13:04:43 -0700437source mm/Kconfig.debug
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800438
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700439config DEBUG_OBJECTS
440 bool "Debug object operations"
441 depends on DEBUG_KERNEL
442 help
443 If you say Y here, additional code will be inserted into the
444 kernel to track the life time of various objects and validate
445 the operations on those objects.
446
447config DEBUG_OBJECTS_SELFTEST
448 bool "Debug objects selftest"
449 depends on DEBUG_OBJECTS
450 help
451 This enables the selftest of the object debug code.
452
453config DEBUG_OBJECTS_FREE
454 bool "Debug objects in freed memory"
455 depends on DEBUG_OBJECTS
456 help
457 This enables checks whether a k/v free operation frees an area
458 which contains an object which has not been deactivated
459 properly. This can make kmalloc/kfree-intensive workloads
460 much slower.
461
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700462config DEBUG_OBJECTS_TIMERS
463 bool "Debug timer objects"
464 depends on DEBUG_OBJECTS
465 help
466 If you say Y here, additional code will be inserted into the
467 timer routines to track the life time of timer objects and
468 validate the timer operations.
469
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900470config DEBUG_OBJECTS_WORK
471 bool "Debug work objects"
472 depends on DEBUG_OBJECTS
473 help
474 If you say Y here, additional code will be inserted into the
475 work queue routines to track the life time of work objects and
476 validate the work operations.
477
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400478config DEBUG_OBJECTS_RCU_HEAD
479 bool "Debug RCU callbacks objects"
Mathieu Desnoyersfc2ecf72011-02-23 09:42:14 -0800480 depends on DEBUG_OBJECTS
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400481 help
482 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
483
Tejun Heoe2852ae2010-10-26 14:23:05 -0700484config DEBUG_OBJECTS_PERCPU_COUNTER
485 bool "Debug percpu counter objects"
486 depends on DEBUG_OBJECTS
487 help
488 If you say Y here, additional code will be inserted into the
489 percpu counter routines to track the life time of percpu counter
490 objects and validate the percpu counter operations.
491
Ingo Molnar3ae70202008-11-26 10:02:00 +0100492config DEBUG_OBJECTS_ENABLE_DEFAULT
493 int "debug_objects bootup default value (0-1)"
494 range 0 1
495 default "1"
496 depends on DEBUG_OBJECTS
497 help
498 Debug objects boot parameter default value
499
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800501 bool "Debug slab memory allocations"
Levin, Alexander (Sasha Levin)4675ff02017-11-15 17:36:02 -0800502 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 help
504 Say Y here to have the kernel do limited verification on memory
505 allocation as well as poisoning memory on free to catch use of freed
506 memory. This can make kmalloc/kfree-intensive workloads much slower.
507
Al Viro871751e2006-03-25 03:06:39 -0800508config DEBUG_SLAB_LEAK
509 bool "Memory leak debugging"
510 depends on DEBUG_SLAB
511
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700512config SLUB_DEBUG_ON
513 bool "SLUB debugging on by default"
Levin, Alexander (Sasha Levin)4675ff02017-11-15 17:36:02 -0800514 depends on SLUB && SLUB_DEBUG
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700515 default n
516 help
517 Boot with debugging on by default. SLUB boots by default with
518 the runtime debug capabilities switched off. Enabling this is
519 equivalent to specifying the "slub_debug" parameter on boot.
520 There is no support for more fine grained debug control like
521 possible with slub_debug=xxx. SLUB debugging may be switched
522 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
523 "slub_debug=-".
524
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800525config SLUB_STATS
526 default n
527 bool "Enable SLUB performance statistics"
Christoph Lameterab4d5ed2010-10-05 13:57:26 -0500528 depends on SLUB && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800529 help
530 SLUB statistics are useful to debug SLUBs allocation behavior in
531 order find ways to optimize the allocator. This should never be
532 enabled for production use since keeping statistics slows down
533 the allocator by a few percentage points. The slabinfo command
534 supports the determination of the most active slabs to figure
535 out which slabs are relevant to a particular load.
536 Try running: slabinfo -DA
537
Catalin Marinasb69ec422012-10-08 16:28:11 -0700538config HAVE_DEBUG_KMEMLEAK
539 bool
540
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100541config DEBUG_KMEMLEAK
542 bool "Kernel memory leak detector"
Kees Cook525c1f92013-01-16 18:54:16 -0800543 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
Catalin Marinas79e0d9b2011-04-27 17:06:19 +0100544 select DEBUG_FS
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100545 select STACKTRACE if STACKTRACE_SUPPORT
546 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800547 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100548 help
549 Say Y here if you want to enable the memory leak
550 detector. The memory allocation/freeing is traced in a way
551 similar to the Boehm's conservative garbage collector, the
552 difference being that the orphan objects are not freed but
553 only shown in /sys/kernel/debug/kmemleak. Enabling this
554 feature will introduce an overhead to memory
Andreas Platschek700199b02016-12-14 15:05:40 -0800555 allocations. See Documentation/dev-tools/kmemleak.rst for more
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100556 details.
557
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100558 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
559 of finding leaks due to the slab objects poisoning.
560
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100561 In order to access the kmemleak file, debugfs needs to be
562 mounted (usually at /sys/kernel/debug).
563
Catalin Marinasa9d90582009-06-25 10:16:11 +0100564config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
565 int "Maximum kmemleak early log entries"
566 depends on DEBUG_KMEMLEAK
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200567 range 200 40000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100568 default 400
569 help
570 Kmemleak must track all the memory allocations to avoid
571 reporting false positives. Since memory may be allocated or
572 freed before kmemleak is initialised, an early log buffer is
573 used to store these actions. If kmemleak reports "early log
574 buffer exceeded", please increase this value.
575
Catalin Marinas0822ee42009-06-11 13:24:14 +0100576config DEBUG_KMEMLEAK_TEST
577 tristate "Simple test for the kernel memory leak detector"
Daniel Baluta97182692011-04-04 15:06:44 -0700578 depends on DEBUG_KMEMLEAK && m
Catalin Marinas0822ee42009-06-11 13:24:14 +0100579 help
Daniel Baluta97182692011-04-04 15:06:44 -0700580 This option enables a module that explicitly leaks memory.
Catalin Marinas0822ee42009-06-11 13:24:14 +0100581
582 If unsure, say N.
583
Jason Baronab0155a2010-07-19 11:54:17 +0100584config DEBUG_KMEMLEAK_DEFAULT_OFF
585 bool "Default kmemleak to off"
586 depends on DEBUG_KMEMLEAK
587 help
588 Say Y here to disable kmemleak by default. It can then be enabled
589 on the command line via kmemleak=on.
590
Dave Hansen0610c8a2013-07-01 13:04:43 -0700591config DEBUG_STACK_USAGE
592 bool "Stack utilization instrumentation"
Helge Deller6c31da32016-03-19 17:54:10 +0100593 depends on DEBUG_KERNEL && !IA64
Dave Hansen0610c8a2013-07-01 13:04:43 -0700594 help
595 Enables the display of the minimum amount of free stack which each
596 task has ever had available in the sysrq-T and sysrq-P debug output.
597
598 This option will slow down process creation somewhat.
599
600config DEBUG_VM
601 bool "Debug VM"
602 depends on DEBUG_KERNEL
603 help
604 Enable this to turn on extended checks in the virtual-memory system
605 that may impact performance.
606
607 If unsure, say N.
608
Davidlohr Bueso4f115142014-06-04 16:06:46 -0700609config DEBUG_VM_VMACACHE
610 bool "Debug VMA caching"
611 depends on DEBUG_VM
612 help
613 Enable this to turn on VMA caching debug information. Doing so
614 can cause significant overhead, so only enable it in non-production
615 environments.
616
617 If unsure, say N.
618
Dave Hansen0610c8a2013-07-01 13:04:43 -0700619config DEBUG_VM_RB
620 bool "Debug VM red-black trees"
621 depends on DEBUG_VM
622 help
Davidlohr Buesoa663dad2014-04-18 15:07:22 -0700623 Enable VM red-black tree debugging information and extra validations.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700624
625 If unsure, say N.
626
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800627config DEBUG_VM_PGFLAGS
628 bool "Debug page-flags operations"
629 depends on DEBUG_VM
630 help
631 Enables extra validation on page flags operations.
632
633 If unsure, say N.
634
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800635config ARCH_HAS_DEBUG_VIRTUAL
636 bool
637
Dave Hansen0610c8a2013-07-01 13:04:43 -0700638config DEBUG_VIRTUAL
639 bool "Debug VM translations"
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800640 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
Dave Hansen0610c8a2013-07-01 13:04:43 -0700641 help
642 Enable some costly sanity checks in virtual to page code. This can
643 catch mistakes with virt_to_page() and friends.
644
645 If unsure, say N.
646
647config DEBUG_NOMMU_REGIONS
648 bool "Debug the global anon/private NOMMU mapping region tree"
649 depends on DEBUG_KERNEL && !MMU
650 help
651 This option causes the global tree of anonymous and private mapping
652 regions to be regularly checked for invalid topology.
653
654config DEBUG_MEMORY_INIT
655 bool "Debug memory initialisation" if EXPERT
656 default !EXPERT
657 help
658 Enable this for additional checks during memory initialisation.
659 The sanity checks verify aspects of the VM such as the memory model
660 and other information provided by the architecture. Verbose
661 information will be printed at KERN_DEBUG loglevel depending
662 on the mminit_loglevel= command-line option.
663
664 If unsure, say Y
665
666config MEMORY_NOTIFIER_ERROR_INJECT
667 tristate "Memory hotplug notifier error injection module"
668 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
669 help
670 This option provides the ability to inject artificial errors to
671 memory hotplug notifier chain callbacks. It is controlled through
672 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
673
674 If the notifier call chain should be failed with some events
675 notified, write the error code to "actions/<notifier event>/error".
676
677 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
678
679 # cd /sys/kernel/debug/notifier-error-inject/memory
680 # echo -12 > actions/MEM_GOING_OFFLINE/error
681 # echo offline > /sys/devices/system/memory/memoryXXX/state
682 bash: echo: write error: Cannot allocate memory
683
684 To compile this code as a module, choose M here: the module will
685 be called memory-notifier-error-inject.
686
687 If unsure, say N.
688
689config DEBUG_PER_CPU_MAPS
690 bool "Debug access to per_cpu maps"
691 depends on DEBUG_KERNEL
692 depends on SMP
693 help
694 Say Y to verify that the per_cpu map being accessed has
695 been set up. This adds a fair amount of code to kernel memory
696 and decreases performance.
697
698 Say N if unsure.
699
700config DEBUG_HIGHMEM
701 bool "Highmem debugging"
702 depends on DEBUG_KERNEL && HIGHMEM
703 help
Geert Uytterhoevenb1357c92014-04-14 18:55:50 +0200704 This option enables additional error checking for high memory
705 systems. Disable for production systems.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700706
707config HAVE_DEBUG_STACKOVERFLOW
708 bool
709
710config DEBUG_STACKOVERFLOW
711 bool "Check for stack overflows"
712 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
713 ---help---
714 Say Y here if you want to check for overflows of kernel, IRQ
Borislav Petkovedb0ec02015-01-25 19:50:34 +0100715 and exception stacks (if your architecture uses them). This
Dave Hansen0610c8a2013-07-01 13:04:43 -0700716 option will show detailed messages if free stack space drops
717 below a certain limit.
718
719 These kinds of bugs usually occur when call-chains in the
720 kernel get too deep, especially when interrupts are
721 involved.
722
723 Use this in cases where you see apparently random memory
724 corruption, especially if it appears in 'struct thread_info'
725
726 If in doubt, say "N".
727
Andrey Ryabinin0b24bec2015-02-13 14:39:17 -0800728source "lib/Kconfig.kasan"
729
Dave Hansen0610c8a2013-07-01 13:04:43 -0700730endmenu # "Memory Debugging"
731
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700732config ARCH_HAS_KCOV
733 bool
734 help
735 KCOV does not have any arch-specific code, but currently it is enabled
736 only for x86_64. KCOV requires testing on other archs, and most likely
737 disabling of instrumentation for some early boot code.
738
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900739config CC_HAS_SANCOV_TRACE_PC
740 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
741
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700742config KCOV
743 bool "Code coverage for fuzzing"
744 depends on ARCH_HAS_KCOV
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900745 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700746 select DEBUG_FS
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900747 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700748 help
749 KCOV exposes kernel code coverage information in a form suitable
750 for coverage-guided fuzzing (randomized testing).
751
752 If RANDOMIZE_BASE is enabled, PC values will not be stable across
753 different machines and across reboots. If you need stable PC values,
754 disable RANDOMIZE_BASE.
755
Andreas Platschek700199b02016-12-14 15:05:40 -0800756 For more details, see Documentation/dev-tools/kcov.rst.
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700757
Victor Chibotarud677a4d2017-11-17 15:30:50 -0800758config KCOV_ENABLE_COMPARISONS
759 bool "Enable comparison operands collection by KCOV"
760 depends on KCOV
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900761 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
Victor Chibotarud677a4d2017-11-17 15:30:50 -0800762 help
763 KCOV also exposes operands of every comparison in the instrumented
764 code along with operand sizes and PCs of the comparison instructions.
765 These operands can be used by fuzzing engines to improve the quality
766 of fuzzing coverage.
767
Vegard Nossuma4691de2016-08-02 14:07:30 -0700768config KCOV_INSTRUMENT_ALL
769 bool "Instrument all code by default"
770 depends on KCOV
Masahiro Yamada5aadfde2018-05-28 18:22:04 +0900771 default y
Vegard Nossuma4691de2016-08-02 14:07:30 -0700772 help
773 If you are doing generic system call fuzzing (like e.g. syzkaller),
774 then you will want to instrument the whole kernel and you should
775 say y here. If you are doing more targeted fuzzing (like e.g.
776 filesystem fuzzing with AFL) then you will want to enable coverage
777 for more specific subsets of files, and should say n here.
778
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779config DEBUG_SHIRQ
780 bool "Debug shared IRQ handlers"
Martin Schwidefsky0244ad02013-08-30 09:39:53 +0200781 depends on DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 help
783 Enable this to generate a spurious interrupt as soon as a shared
784 interrupt handler is registered, and just before one is deregistered.
785 Drivers ought to be able to handle interrupts coming in at those
786 points; some don't and need to be caught.
787
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700788menu "Debug Lockups and Hangs"
789
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790config LOCKUP_DETECTOR
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700791 bool
792
793config SOFTLOCKUP_DETECTOR
794 bool "Detect Soft Lockups"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 depends on DEBUG_KERNEL && !S390
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700796 select LOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 help
798 Say Y here to enable the kernel to act as a watchdog to detect
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700799 soft lockups.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800
801 Softlockups are bugs that cause the kernel to loop in kernel
802 mode for more than 20 seconds, without giving other tasks a
803 chance to run. The current stack trace is displayed upon
804 detection and the system will stay locked up.
805
Randy Dunlap5f00ae02018-04-10 16:32:51 -0700806config BOOTPARAM_SOFTLOCKUP_PANIC
807 bool "Panic (Reboot) On Soft Lockups"
808 depends on SOFTLOCKUP_DETECTOR
809 help
810 Say Y here to enable the kernel to panic on "soft lockups",
811 which are bugs that cause the kernel to loop in kernel
812 mode for more than 20 seconds (configurable using the watchdog_thresh
813 sysctl), without giving other tasks a chance to run.
814
815 The panic can be used in combination with panic_timeout,
816 to cause the system to reboot automatically after a
817 lockup has been detected. This feature is useful for
818 high-availability systems that have uptime guarantees and
819 where a lockup must be resolved ASAP.
820
821 Say N if unsure.
822
823config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
824 int
825 depends on SOFTLOCKUP_DETECTOR
826 range 0 1
827 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
828 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
829
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700830config HARDLOCKUP_DETECTOR_PERF
831 bool
832 select SOFTLOCKUP_DETECTOR
833
834#
Thomas Gleixner7edaeb62017-08-15 09:50:13 +0200835# Enables a timestamp based low pass filter to compensate for perf based
836# hard lockup detection which runs too fast due to turbo modes.
837#
838config HARDLOCKUP_CHECK_TIMESTAMP
839 bool
840
841#
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700842# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
843# lockup detector rather than the perf based detector.
844#
845config HARDLOCKUP_DETECTOR
846 bool "Detect Hard Lockups"
847 depends on DEBUG_KERNEL && !S390
848 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
849 select LOCKUP_DETECTOR
850 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
851 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
852 help
853 Say Y here to enable the kernel to act as a watchdog to detect
854 hard lockups.
855
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 Hardlockups are bugs that cause the CPU to loop in kernel mode
857 for more than 10 seconds, without letting other interrupts have a
858 chance to run. The current stack trace is displayed upon detection
859 and the system will stay locked up.
860
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861config BOOTPARAM_HARDLOCKUP_PANIC
862 bool "Panic (Reboot) On Hard Lockups"
863 depends on HARDLOCKUP_DETECTOR
864 help
865 Say Y here to enable the kernel to panic on "hard lockups",
866 which are bugs that cause the kernel to loop in kernel
867 mode with interrupts disabled for more than 10 seconds (configurable
868 using the watchdog_thresh sysctl).
869
870 Say N if unsure.
871
872config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
873 int
874 depends on HARDLOCKUP_DETECTOR
875 range 0 1
876 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
877 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
878
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879config DETECT_HUNG_TASK
880 bool "Detect Hung Tasks"
881 depends on DEBUG_KERNEL
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700882 default SOFTLOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883 help
884 Say Y here to enable the kernel to detect "hung tasks",
885 which are bugs that cause the task to be stuck in
Vivien Didelot96b03ab2016-09-22 16:55:13 -0400886 uninterruptible "D" state indefinitely.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887
888 When a hung task is detected, the kernel will print the
889 current stack trace (which you should report), but the
890 task will stay in uninterruptible state. If lockdep is
891 enabled then all held locks will also be reported. This
892 feature has negligible overhead.
893
894config DEFAULT_HUNG_TASK_TIMEOUT
895 int "Default timeout for hung task detection (in seconds)"
896 depends on DETECT_HUNG_TASK
897 default 120
898 help
Ingo Molnar8637c092006-07-03 00:24:38 -0700899 This option controls the default timeout (in seconds) used
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900 to determine when a task has become non-responsive and should
901 be considered hung.
902
903 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
904 sysctl or by writing a value to
905 /proc/sys/kernel/hung_task_timeout_secs.
906
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700907 A timeout of 0 disables the check. The default is two minutes.
908 Keeping the default should be fine in most cases.
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700909
910config BOOTPARAM_HUNG_TASK_PANIC
911 bool "Panic (Reboot) On Hung Tasks"
912 depends on DETECT_HUNG_TASK
913 help
914 Say Y here to enable the kernel to panic on "hung tasks",
915 which are bugs that cause the kernel to leave a task stuck
916 in uninterruptible "D" state.
917
918 The panic can be used in combination with panic_timeout,
Thomas Gleixner61a87122006-06-27 02:54:56 -0700919 to cause the system to reboot automatically after a
920 hung task has been detected. This feature is useful for
Roman Zippela1583d32006-06-27 02:55:00 -0700921 high-availability systems that have uptime guarantees and
Thomas Gleixner61a87122006-06-27 02:54:56 -0700922 where a hung tasks must be resolved ASAP.
923
924 Say N if unsure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100926config BOOTPARAM_HUNG_TASK_PANIC_VALUE
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 int
928 depends on DETECT_HUNG_TASK
929 range 0 1
930 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
931 default 1 if BOOTPARAM_HUNG_TASK_PANIC
932
Tejun Heo82607adc2015-12-08 11:28:04 -0500933config WQ_WATCHDOG
934 bool "Detect Workqueue Stalls"
935 depends on DEBUG_KERNEL
936 help
937 Say Y here to enable stall detection on workqueues. If a
938 worker pool doesn't make forward progress on a pending work
939 item for over a given amount of time, 30s by default, a
940 warning message is printed along with dump of workqueue
941 state. This can be configured through kernel parameter
942 "workqueue.watchdog_thresh" and its sysfs counterpart.
943
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700944endmenu # "Debug lockups and hangs"
945
946config PANIC_ON_OOPS
947 bool "Panic on Oops"
948 help
949 Say Y here to enable the kernel to panic when it oopses. This
950 has the same effect as setting oops=panic on the kernel command
951 line.
952
953 This feature is useful to ensure that the kernel does not do
954 anything erroneous after an oops which could result in data
955 corruption or other issues.
956
957 Say N if unsure.
958
959config PANIC_ON_OOPS_VALUE
960 int
961 range 0 1
962 default 0 if !PANIC_ON_OOPS
963 default 1 if PANIC_ON_OOPS
964
Jason Baron5800dc32013-11-25 23:23:04 +0000965config PANIC_TIMEOUT
966 int "panic timeout"
967 default 0
968 help
969 Set the timeout value (in seconds) until a reboot occurs when the
970 the kernel panics. If n = 0, then we wait forever. A timeout
971 value n > 0 will wait n seconds before rebooting, while a timeout
972 value n < 0 will reboot immediately.
973
Linus Torvalds1da177e2005-04-16 15:20:36 -0700974config SCHED_DEBUG
975 bool "Collect scheduler debugging info"
976 depends on DEBUG_KERNEL && PROC_FS
977 default y
978 help
979 If you say Y here, the /proc/sched_debug file will be provided
980 that can help debug the scheduler. The runtime overhead of this
981 option is minimal.
982
Naveen N. Raof6db8342015-06-25 23:53:37 +0530983config SCHED_INFO
984 bool
985 default n
986
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987config SCHEDSTATS
988 bool "Collect scheduler statistics"
989 depends on DEBUG_KERNEL && PROC_FS
Naveen N. Raof6db8342015-06-25 23:53:37 +0530990 select SCHED_INFO
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991 help
992 If you say Y here, additional code will be inserted into the
993 scheduler and related routines to collect statistics about
994 scheduler behavior and provide them in /proc/schedstat. These
995 stats may be useful for both tuning and debugging the scheduler
996 If you aren't debugging the scheduler or trying to tune a specific
997 application, you can say N to avoid the very slight overhead
998 this adds.
999
Aaron Tomlin0d9e2632014-09-12 14:16:19 +01001000config SCHED_STACK_END_CHECK
1001 bool "Detect stack corruption on calls to schedule()"
1002 depends on DEBUG_KERNEL
1003 default n
1004 help
1005 This option checks for a stack overrun on calls to schedule().
1006 If the stack end location is found to be over written always panic as
1007 the content of the corrupted region can no longer be trusted.
1008 This is to ensure no erroneous behaviour occurs which could result in
1009 data corruption or a sporadic crash at a later stage once the region
1010 is examined. The runtime overhead introduced is minimal.
1011
John Stultz3c17ad12015-03-11 21:16:32 -07001012config DEBUG_TIMEKEEPING
1013 bool "Enable extra timekeeping sanity checking"
1014 help
1015 This option will enable additional timekeeping sanity checks
1016 which may be helpful when diagnosing issues where timekeeping
1017 problems are suspected.
1018
1019 This may include checks in the timekeeping hotpaths, so this
1020 option may have a (very small) performance impact to some
1021 workloads.
1022
1023 If unsure, say N.
1024
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025config DEBUG_PREEMPT
1026 bool "Debug preemptible kernel"
Kumar Gala01deab92009-10-16 07:21:39 +00001027 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001028 default y
1029 help
1030 If you say Y here then the kernel will use a debug variant of the
1031 commonly used smp_processor_id() function and will print warnings
1032 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1033 will detect preemption count underflows.
1034
Dave Hansen9eade162013-07-01 13:04:47 -07001035menu "Lock Debugging (spinlocks, mutexes, etc...)"
1036
Waiman Longf07cbeb2018-03-30 17:27:59 -04001037config LOCK_DEBUGGING_SUPPORT
1038 bool
1039 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1040 default y
1041
Waiman Long19193bc2018-03-30 17:28:00 -04001042config PROVE_LOCKING
1043 bool "Lock debugging: prove locking correctness"
1044 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1045 select LOCKDEP
1046 select DEBUG_SPINLOCK
1047 select DEBUG_MUTEXES
1048 select DEBUG_RT_MUTEXES if RT_MUTEXES
1049 select DEBUG_RWSEMS if RWSEM_SPIN_ON_OWNER
1050 select DEBUG_WW_MUTEX_SLOWPATH
1051 select DEBUG_LOCK_ALLOC
1052 select TRACE_IRQFLAGS
1053 default n
1054 help
1055 This feature enables the kernel to prove that all locking
1056 that occurs in the kernel runtime is mathematically
1057 correct: that under no circumstance could an arbitrary (and
1058 not yet triggered) combination of observed locking
1059 sequences (on an arbitrary number of CPUs, running an
1060 arbitrary number of tasks and interrupt contexts) cause a
1061 deadlock.
1062
1063 In short, this feature enables the kernel to report locking
1064 related deadlocks before they actually occur.
1065
1066 The proof does not depend on how hard and complex a
1067 deadlock scenario would be to trigger: how many
1068 participant CPUs, tasks and irq-contexts would be needed
1069 for it to trigger. The proof also does not depend on
1070 timing: if a race and a resulting deadlock is possible
1071 theoretically (no matter how unlikely the race scenario
1072 is), it will be proven so and will immediately be
1073 reported by the kernel (once the event is observed that
1074 makes the deadlock theoretically possible).
1075
1076 If a deadlock is impossible (i.e. the locking rules, as
1077 observed by the kernel, are mathematically correct), the
1078 kernel reports nothing.
1079
1080 NOTE: this feature can also be enabled for rwlocks, mutexes
1081 and rwsems - in which case all dependencies between these
1082 different locking variants are observed and mapped too, and
1083 the proof of observed correctness is also maintained for an
1084 arbitrary combination of these separate locking variants.
1085
1086 For more details, see Documentation/locking/lockdep-design.txt.
1087
1088config LOCK_STAT
1089 bool "Lock usage statistics"
1090 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1091 select LOCKDEP
1092 select DEBUG_SPINLOCK
1093 select DEBUG_MUTEXES
1094 select DEBUG_RT_MUTEXES if RT_MUTEXES
1095 select DEBUG_LOCK_ALLOC
1096 default n
1097 help
1098 This feature enables tracking lock contention points
1099
1100 For more details, see Documentation/locking/lockstat.txt
1101
1102 This also enables lock events required by "perf lock",
1103 subcommand of perf.
1104 If you want to use "perf lock", you also need to turn on
1105 CONFIG_EVENT_TRACING.
1106
1107 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1108 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1109
Linus Torvalds1da177e2005-04-16 15:20:36 -07001110config DEBUG_RT_MUTEXES
1111 bool "RT Mutex debugging, deadlock detection"
1112 depends on DEBUG_KERNEL && RT_MUTEXES
1113 help
1114 This allows rt mutex semantics violations and rt mutex related
1115 deadlocks (lockups) to be detected and reported automatically.
1116
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001118 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +05301120 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121 help
1122 Say Y here and build SMP to catch missing spinlock initialization
1123 and certain other kinds of spinlock errors commonly made. This is
1124 best used in conjunction with the NMI watchdog so that spinlock
1125 deadlocks are also debuggable.
1126
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001127config DEBUG_MUTEXES
1128 bool "Mutex debugging: basic checks"
1129 depends on DEBUG_KERNEL
1130 help
1131 This feature allows mutex semantics violations to be detected and
1132 reported.
1133
Daniel Vetter23010022013-06-20 13:31:17 +02001134config DEBUG_WW_MUTEX_SLOWPATH
1135 bool "Wait/wound mutex debugging: Slowpath testing"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001136 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Daniel Vetter23010022013-06-20 13:31:17 +02001137 select DEBUG_LOCK_ALLOC
1138 select DEBUG_SPINLOCK
1139 select DEBUG_MUTEXES
1140 help
1141 This feature enables slowpath testing for w/w mutex users by
1142 injecting additional -EDEADLK wound/backoff cases. Together with
1143 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1144 will test all possible w/w mutex interface abuse with the
1145 exception of simply not acquiring all the required locks.
Rob Clark4d692372014-08-27 11:19:26 -04001146 Note that this feature can introduce significant overhead, so
1147 it really should not be enabled in a production or distro kernel,
1148 even a debug kernel. If you are a driver writer, enable it. If
1149 you are a distro, do not.
Daniel Vetter23010022013-06-20 13:31:17 +02001150
Waiman Long5149cba2018-03-30 17:27:58 -04001151config DEBUG_RWSEMS
1152 bool "RW Semaphore debugging: basic checks"
1153 depends on DEBUG_KERNEL && RWSEM_SPIN_ON_OWNER
1154 help
1155 This debugging feature allows mismatched rw semaphore locks and unlocks
1156 to be detected and reported.
1157
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001158config DEBUG_LOCK_ALLOC
1159 bool "Lock debugging: detect incorrect freeing of live locks"
Waiman Longf07cbeb2018-03-30 17:27:59 -04001160 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001161 select DEBUG_SPINLOCK
1162 select DEBUG_MUTEXES
Peter Zijlstraf5694782016-09-19 12:15:37 +02001163 select DEBUG_RT_MUTEXES if RT_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001164 select LOCKDEP
1165 help
1166 This feature will check whether any held lock (spinlock, rwlock,
1167 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1168 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1169 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1170 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1171 held during task exit.
1172
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001173config LOCKDEP
1174 bool
Waiman Longf07cbeb2018-03-30 17:27:59 -04001175 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001176 select STACKTRACE
Linus Torvaldsf5a8eb62018-04-02 20:20:12 -07001177 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC && !X86
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001178 select KALLSYMS
1179 select KALLSYMS_ALL
1180
Daniel Jordan395102d2017-04-10 11:50:52 -04001181config LOCKDEP_SMALL
1182 bool
1183
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001184config DEBUG_LOCKDEP
1185 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -07001186 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001187 help
1188 If you say Y here, the lock dependency engine will do
1189 additional runtime checks to debug itself, at the price
1190 of more runtime overhead.
1191
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001192config DEBUG_ATOMIC_SLEEP
1193 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +02001194 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195 depends on DEBUG_KERNEL
1196 help
1197 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001198 noisy if they are called inside atomic sections: when a spinlock is
1199 held, inside an rcu read side critical section, inside preempt disabled
1200 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201
Ingo Molnarcae2ed92006-07-03 00:24:48 -07001202config DEBUG_LOCKING_API_SELFTESTS
1203 bool "Locking API boot-time self-tests"
1204 depends on DEBUG_KERNEL
1205 help
1206 Say Y here if you want the kernel to run a short self-test during
1207 bootup. The self-test checks whether common types of locking bugs
1208 are detected by debugging mechanisms or not. (if you disable
1209 lock debugging then those bugs wont be detected of course.)
1210 The following locking APIs are covered: spinlocks, rwlocks,
1211 mutexes and rwsems.
1212
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001213config LOCK_TORTURE_TEST
1214 tristate "torture tests for locking"
1215 depends on DEBUG_KERNEL
1216 select TORTURE_TEST
1217 default n
1218 help
1219 This option provides a kernel module that runs torture tests
1220 on kernel locking primitives. The kernel module may be built
1221 after the fact on the running kernel to be tested, if desired.
1222
1223 Say Y here if you want kernel locking-primitive torture tests
1224 to be built into the kernel.
1225 Say M if you want these torture tests to build as a module.
1226 Say N if you are unsure.
1227
Chris Wilsonf2a5fec2016-12-01 11:47:06 +00001228config WW_MUTEX_SELFTEST
1229 tristate "Wait/wound mutex selftests"
1230 help
1231 This option provides a kernel module that runs tests on the
1232 on the struct ww_mutex locking API.
1233
1234 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1235 with this test harness.
1236
1237 Say M if you want these self tests to build as a module.
1238 Say N if you are unsure.
1239
Dave Hansen9eade162013-07-01 13:04:47 -07001240endmenu # lock debugging
1241
1242config TRACE_IRQFLAGS
1243 bool
1244 help
1245 Enables hooks to interrupt enabling and disabling for
1246 either tracing or lock debugging.
1247
Ingo Molnar8637c092006-07-03 00:24:38 -07001248config STACKTRACE
Dave Jones0c38e1f2014-08-29 15:18:35 -07001249 bool "Stack backtrace support"
Ingo Molnar8637c092006-07-03 00:24:38 -07001250 depends on STACKTRACE_SUPPORT
Dave Jones0c38e1f2014-08-29 15:18:35 -07001251 help
1252 This option causes the kernel to create a /proc/pid/stack for
1253 every process, showing its current stack trace.
1254 It is also used by various kernel debugging features that require
1255 stack trace generation.
Ingo Molnar8637c092006-07-03 00:24:38 -07001256
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001257config WARN_ALL_UNSEEDED_RANDOM
1258 bool "Warn for all uses of unseeded randomness"
1259 default n
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001260 help
1261 Some parts of the kernel contain bugs relating to their use of
1262 cryptographically secure random numbers before it's actually possible
1263 to generate those numbers securely. This setting ensures that these
1264 flaws don't go unnoticed, by enabling a message, should this ever
1265 occur. This will allow people with obscure setups to know when things
1266 are going wrong, so that they might contact developers about fixing
1267 it.
1268
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001269 Unfortunately, on some models of some architectures getting
1270 a fully seeded CRNG is extremely difficult, and so this can
1271 result in dmesg getting spammed for a surprisingly long
1272 time. This is really bad from a security perspective, and
1273 so architecture maintainers really need to do what they can
1274 to get the CRNG seeded sooner after the system is booted.
1275 However, since users can not do anything actionble to
1276 address this, by default the kernel will issue only a single
1277 warning for the first use of unseeded randomness.
1278
1279 Say Y here if you want to receive warnings for all uses of
1280 unseeded randomness. This will be of use primarily for
1281 those developers interersted in improving the security of
1282 Linux kernels running on their architecture (or
1283 subarchitecture).
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001284
Linus Torvalds1da177e2005-04-16 15:20:36 -07001285config DEBUG_KOBJECT
1286 bool "kobject debugging"
1287 depends on DEBUG_KERNEL
1288 help
1289 If you say Y here, some extra kobject debugging messages will be sent
1290 to the syslog.
1291
Russell Kingc817a672013-06-27 15:06:14 +01001292config DEBUG_KOBJECT_RELEASE
1293 bool "kobject release debugging"
Linus Torvalds2a999aa2013-10-29 08:33:36 -07001294 depends on DEBUG_OBJECTS_TIMERS
Russell Kingc817a672013-06-27 15:06:14 +01001295 help
1296 kobjects are reference counted objects. This means that their
1297 last reference count put is not predictable, and the kobject can
1298 live on past the point at which a driver decides to drop it's
1299 initial reference to the kobject gained on allocation. An
1300 example of this would be a struct device which has just been
1301 unregistered.
1302
1303 However, some buggy drivers assume that after such an operation,
1304 the memory backing the kobject can be immediately freed. This
1305 goes completely against the principles of a refcounted object.
1306
1307 If you say Y here, the kernel will delay the release of kobjects
1308 on the last reference count to improve the visibility of this
1309 kind of kobject release bug.
1310
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001311config HAVE_DEBUG_BUGVERBOSE
1312 bool
1313
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314config DEBUG_BUGVERBOSE
David Rientjes6a108a12011-01-20 14:44:16 -08001315 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001316 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
Alexey Dobriyan8420e7e2009-12-14 18:00:25 -08001317 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318 help
1319 Say Y here to make BUG() panics output the file name and line number
1320 of the BUG call as well as the EIP and oops trace. This aids
1321 debugging but costs about 70-100K of memory.
1322
Dave Jones199a9af2006-09-29 01:59:00 -07001323config DEBUG_LIST
1324 bool "Debug linked list manipulation"
Arnd Bergmann4520bcb2016-08-26 17:42:00 +02001325 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
Dave Jones199a9af2006-09-29 01:59:00 -07001326 help
1327 Enable this to turn on extended checks in the linked-list
1328 walking routines.
1329
1330 If unsure, say N.
1331
Dan Streetmanb8cfff62014-06-04 16:11:54 -07001332config DEBUG_PI_LIST
1333 bool "Debug priority linked list manipulation"
1334 depends on DEBUG_KERNEL
1335 help
1336 Enable this to turn on extended checks in the priority-ordered
1337 linked-list (plist) walking routines. This checks the entire
1338 list multiple times during each manipulation.
1339
1340 If unsure, say N.
1341
Jens Axboed6ec0842007-10-22 20:01:06 +02001342config DEBUG_SG
1343 bool "Debug SG table operations"
1344 depends on DEBUG_KERNEL
1345 help
1346 Enable this to turn on checks on scatter-gather tables. This can
1347 help find problems with drivers that do not properly initialize
1348 their sg tables.
1349
1350 If unsure, say N.
1351
Arjan van de Ven1b2439d2008-08-15 15:29:38 -07001352config DEBUG_NOTIFIERS
1353 bool "Debug notifier call chains"
1354 depends on DEBUG_KERNEL
1355 help
1356 Enable this to turn on sanity checking for notifier call chains.
1357 This is most useful for kernel developers to make sure that
1358 modules properly unregister themselves from notifier chains.
1359 This is a relatively cheap check but if you care about maximum
1360 performance, say N.
1361
David Howellse0e81732009-09-02 09:13:40 +01001362config DEBUG_CREDENTIALS
1363 bool "Debug credential management"
1364 depends on DEBUG_KERNEL
1365 help
1366 Enable this to turn on some debug checking for credential
1367 management. The additional code keeps track of the number of
1368 pointers from task_structs to any given cred struct, and checks to
1369 see that this number never exceeds the usage count of the cred
1370 struct.
1371
1372 Furthermore, if SELinux is enabled, this also checks that the
1373 security pointer in the cred struct is never seen to be invalid.
1374
1375 If unsure, say N.
1376
Paul E. McKenney43a0a2a2017-05-17 09:19:44 -07001377source "kernel/rcu/Kconfig.debug"
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001378
Tejun Heof303fcc2016-02-09 17:59:38 -05001379config DEBUG_WQ_FORCE_RR_CPU
1380 bool "Force round-robin CPU selection for unbound work items"
1381 depends on DEBUG_KERNEL
1382 default n
1383 help
1384 Workqueue used to implicitly guarantee that work items queued
1385 without explicit CPU specified are put on the local CPU. This
1386 guarantee is no longer true and while local CPU is still
1387 preferred work items may be put on foreign CPUs. Kernel
1388 parameter "workqueue.debug_force_rr_cpu" is added to force
1389 round-robin CPU selection to flush out usages which depend on the
1390 now broken guarantee. This config option enables the debug
1391 feature by default. When enabled, memory and cache locality will
1392 be impacted.
1393
Tejun Heo870d6652008-08-25 19:47:25 +09001394config DEBUG_BLOCK_EXT_DEVT
1395 bool "Force extended block device numbers and spread them"
1396 depends on DEBUG_KERNEL
1397 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +02001398 default n
Tejun Heo870d6652008-08-25 19:47:25 +09001399 help
Tejun Heo0e11e342008-10-13 10:46:01 +02001400 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1401 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1402 YOU ARE DOING. Distros, please enable this and fix whatever
1403 is broken.
1404
Tejun Heo870d6652008-08-25 19:47:25 +09001405 Conventionally, block device numbers are allocated from
1406 predetermined contiguous area. However, extended block area
1407 may introduce non-contiguous block device numbers. This
1408 option forces most block device numbers to be allocated from
1409 the extended space and spreads them to discover kernel or
1410 userland code paths which assume predetermined contiguous
1411 device number allocation.
1412
Tejun Heo55dc7db2008-09-01 13:44:35 +02001413 Note that turning on this debug option shuffles all the
1414 device numbers for all IDE and SCSI devices including libata
1415 ones, so root partition specified using device number
1416 directly (via rdev or root=MAJ:MIN) won't work anymore.
1417 Textual device names (root=/dev/sdXn) will continue to work.
1418
Tejun Heo870d6652008-08-25 19:47:25 +09001419 Say N if you are unsure.
1420
Thomas Gleixner757c9892016-02-26 18:43:32 +00001421config CPU_HOTPLUG_STATE_CONTROL
1422 bool "Enable CPU hotplug state control"
1423 depends on DEBUG_KERNEL
1424 depends on HOTPLUG_CPU
1425 default n
1426 help
1427 Allows to write steps between "offline" and "online" to the CPUs
1428 sysfs target file so states can be stepped granular. This is a debug
1429 option for now as the hotplug machinery cannot be stopped and
1430 restarted at arbitrary points yet.
1431
1432 Say N if your are unsure.
1433
Akinobu Mita8d438282012-07-30 14:43:02 -07001434config NOTIFIER_ERROR_INJECTION
1435 tristate "Notifier error injection"
1436 depends on DEBUG_KERNEL
1437 select DEBUG_FS
1438 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001439 This option provides the ability to inject artificial errors to
Akinobu Mita8d438282012-07-30 14:43:02 -07001440 specified notifier chain callbacks. It is useful to test the error
1441 handling of notifier call chain failures.
1442
1443 Say N if unsure.
1444
Akinobu Mita048b9c32012-07-30 14:43:07 -07001445config PM_NOTIFIER_ERROR_INJECT
1446 tristate "PM notifier error injection module"
1447 depends on PM && NOTIFIER_ERROR_INJECTION
1448 default m if PM_DEBUG
1449 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001450 This option provides the ability to inject artificial errors to
Akinobu Mita048b9c32012-07-30 14:43:07 -07001451 PM notifier chain callbacks. It is controlled through debugfs
1452 interface /sys/kernel/debug/notifier-error-inject/pm
1453
1454 If the notifier call chain should be failed with some events
1455 notified, write the error code to "actions/<notifier event>/error".
1456
1457 Example: Inject PM suspend error (-12 = -ENOMEM)
1458
1459 # cd /sys/kernel/debug/notifier-error-inject/pm/
1460 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1461 # echo mem > /sys/power/state
1462 bash: echo: write error: Cannot allocate memory
1463
1464 To compile this code as a module, choose M here: the module will
1465 be called pm-notifier-error-inject.
1466
1467 If unsure, say N.
1468
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001469config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1470 tristate "OF reconfig notifier error injection module"
1471 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001472 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001473 This option provides the ability to inject artificial errors to
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001474 OF reconfig notifier chain callbacks. It is controlled
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001475 through debugfs interface under
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001476 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001477
1478 If the notifier call chain should be failed with some events
1479 notified, write the error code to "actions/<notifier event>/error".
1480
1481 To compile this code as a module, choose M here: the module will
Akinobu Mitae12a95f2013-04-30 15:28:49 -07001482 be called of-reconfig-notifier-error-inject.
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001483
1484 If unsure, say N.
1485
Nikolay Aleksandrov02fff962015-11-28 13:45:28 +01001486config NETDEV_NOTIFIER_ERROR_INJECT
1487 tristate "Netdev notifier error injection module"
1488 depends on NET && NOTIFIER_ERROR_INJECTION
1489 help
1490 This option provides the ability to inject artificial errors to
1491 netdevice notifier chain callbacks. It is controlled through debugfs
1492 interface /sys/kernel/debug/notifier-error-inject/netdev
1493
1494 If the notifier call chain should be failed with some events
1495 notified, write the error code to "actions/<notifier event>/error".
1496
1497 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1498
1499 # cd /sys/kernel/debug/notifier-error-inject/netdev
1500 # echo -22 > actions/NETDEV_CHANGEMTU/error
1501 # ip link set eth0 mtu 1024
1502 RTNETLINK answers: Invalid argument
1503
1504 To compile this code as a module, choose M here: the module will
1505 be called netdev-notifier-error-inject.
1506
1507 If unsure, say N.
1508
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001509config FUNCTION_ERROR_INJECTION
1510 def_bool y
1511 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1512
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001513config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001514 bool "Fault-injection framework"
1515 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001516 help
1517 Provide fault-injection framework.
1518 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001519
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001520config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001521 bool "Fault-injection capability for kmalloc"
1522 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001523 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001524 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001525 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001526
Akinobu Mita933e3122006-12-08 02:39:45 -08001527config FAIL_PAGE_ALLOC
1528 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001529 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001530 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001531 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001532
Akinobu Mitac17bb492006-12-08 02:39:46 -08001533config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001534 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001535 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001536 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001537 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001538
Jens Axboe581d4e22008-09-14 05:56:33 -07001539config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d01432010-07-21 16:05:53 +09001540 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001541 depends on FAULT_INJECTION && BLOCK
1542 help
1543 Provide fault-injection capability on end IO handling. This
1544 will make the block layer "forget" an interrupt as configured,
1545 thus exercising the error handling.
1546
1547 Only works with drivers that use the generic timeout handling,
1548 for others it wont do anything.
1549
Davidlohr Buesoab51fba2015-06-29 23:26:02 -07001550config FAIL_FUTEX
1551 bool "Fault-injection capability for futexes"
1552 select DEBUG_FS
1553 depends on FAULT_INJECTION && FUTEX
1554 help
1555 Provide fault-injection capability for futexes.
1556
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001557config FAULT_INJECTION_DEBUG_FS
1558 bool "Debugfs entries for fault-injection capabilities"
1559 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1560 help
1561 Enable configuration of fault-injection capabilities via debugfs.
1562
Masami Hiramatsu4b1a29a2018-01-13 02:56:03 +09001563config FAIL_FUNCTION
1564 bool "Fault-injection capability for functions"
1565 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1566 help
1567 Provide function-based fault-injection capability.
1568 This will allow you to override a specific function with a return
1569 with given return value. As a result, function caller will see
1570 an error value and have to handle it. This is useful to test the
1571 error handling in various subsystems.
1572
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001573config FAIL_MMC_REQUEST
1574 bool "Fault-injection capability for MMC IO"
1575 depends on FAULT_INJECTION_DEBUG_FS && MMC
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001576 help
Mikulas Patockaf1b4bd02018-06-14 15:27:48 -07001577 Provide fault-injection capability for MMC IO.
1578 This will make the mmc core return data errors. This is
1579 useful to test the error handling in the mmc block device
1580 and to test how the mmc host driver handles retries from
1581 the block device.
Akinobu Mita1df49002007-02-20 13:57:56 -08001582
1583config FAULT_INJECTION_STACKTRACE_FILTER
1584 bool "stacktrace filter for fault-injection capabilities"
1585 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001586 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001587 select STACKTRACE
Arnd Bergmanna687a532018-03-07 23:30:54 +01001588 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !X86
Akinobu Mita1df49002007-02-20 13:57:56 -08001589 help
1590 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001591
Arjan van de Ven97455122008-01-25 21:08:34 +01001592config LATENCYTOP
1593 bool "Latency measuring infrastructure"
Randy Dunlap625fdca2010-08-12 12:31:21 -07001594 depends on DEBUG_KERNEL
1595 depends on STACKTRACE_SUPPORT
1596 depends on PROC_FS
Josh Poimboeufa34a7662017-07-24 18:36:58 -05001597 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !X86
Arjan van de Ven97455122008-01-25 21:08:34 +01001598 select KALLSYMS
1599 select KALLSYMS_ALL
1600 select STACKTRACE
1601 select SCHEDSTATS
1602 select SCHED_DEBUG
Arjan van de Ven97455122008-01-25 21:08:34 +01001603 help
1604 Enable this option if you want to use the LatencyTOP tool
1605 to find out which userspace is blocking on what kernel operations.
1606
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001607source kernel/trace/Kconfig
1608
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001609config PROVIDE_OHCI1394_DMA_INIT
1610 bool "Remote debugging over FireWire early on boot"
1611 depends on PCI && X86
1612 help
1613 If you want to debug problems which hang or crash the kernel early
1614 on boot and the crashing machine has a FireWire port, you can use
1615 this feature to remotely access the memory of the crashed machine
1616 over FireWire. This employs remote DMA as part of the OHCI1394
1617 specification which is now the standard for FireWire controllers.
1618
1619 With remote DMA, you can monitor the printk buffer remotely using
1620 firescope and access all memory below 4GB using fireproxy from gdb.
1621 Even controlling a kernel debugger is possible using remote DMA.
1622
1623 Usage:
1624
1625 If ohci1394_dma=early is used as boot parameter, it will initialize
1626 all OHCI1394 controllers which are found in the PCI config space.
1627
1628 As all changes to the FireWire bus such as enabling and disabling
1629 devices cause a bus reset and thereby disable remote DMA for all
1630 devices, be sure to have the cable plugged and FireWire enabled on
1631 the debugging host before booting the debug target for debugging.
1632
1633 This code (~1k) is freed after boot. By then, the firewire stack
1634 in charge of the OHCI-1394 controllers should be used instead.
1635
1636 See Documentation/debugging-via-ohci1394.txt for more information.
1637
1638config DMA_API_DEBUG
1639 bool "Enable debugging of DMA-API usage"
Christoph Hellwigf616ab52018-05-09 06:53:49 +02001640 select NEED_DMA_MAP_STATE
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001641 help
1642 Enable this option to debug the use of the DMA API by device drivers.
1643 With this option you will be able to detect common bugs in device
1644 drivers like double-freeing of DMA mappings or freeing mappings that
1645 were never allocated.
1646
1647 This also attempts to catch cases where a page owned by DMA is
1648 accessed by the cpu in a way that could cause data corruption. For
1649 example, this enables cow_user_page() to check that the source page is
1650 not undergoing DMA.
1651
1652 This option causes a performance degradation. Use only if you want to
1653 debug device drivers and dma interactions.
1654
1655 If unsure, say N.
1656
Robin Murphy78c47832018-05-21 12:35:13 +01001657config DMA_API_DEBUG_SG
1658 bool "Debug DMA scatter-gather usage"
1659 default y
1660 depends on DMA_API_DEBUG
1661 help
1662 Perform extra checking that callers of dma_map_sg() have respected the
1663 appropriate segment length/boundary limits for the given device when
1664 preparing DMA scatterlists.
1665
1666 This is particularly likely to have been overlooked in cases where the
1667 dma_map_sg() API is used for general bulk mapping of pages rather than
1668 preparing literal scatter-gather descriptors, where there is a risk of
1669 unexpected behaviour from DMA API implementations if the scatterlist
1670 is technically out-of-spec.
1671
1672 If unsure, say N.
1673
Vincent Legolld3deafa2018-02-06 15:38:38 -08001674menuconfig RUNTIME_TESTING_MENU
1675 bool "Runtime Testing"
Anders Roxell908009e82018-02-21 14:46:05 -08001676 def_bool y
Vincent Legolld3deafa2018-02-06 15:38:38 -08001677
1678if RUNTIME_TESTING_MENU
Dave Hansen881c5142013-07-01 13:04:44 -07001679
1680config LKDTM
1681 tristate "Linux Kernel Dump Test Tool Module"
1682 depends on DEBUG_FS
1683 depends on BLOCK
1684 default n
1685 help
1686 This module enables testing of the different dumping mechanisms by
1687 inducing system failures at predefined crash points.
1688 If you don't need it: say N
1689 Choose M here to compile this code as a module. The module will be
1690 called lkdtm.
1691
1692 Documentation on how to use the module can be found in
1693 Documentation/fault-injection/provoke-crashes.txt
1694
1695config TEST_LIST_SORT
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001696 tristate "Linked list sorting test"
1697 depends on DEBUG_KERNEL || m
Dave Hansen881c5142013-07-01 13:04:44 -07001698 help
1699 Enable this to turn on 'list_sort()' function test. This test is
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001700 executed only once during system boot (so affects only boot time),
1701 or at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001702
1703 If unsure, say N.
1704
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001705config TEST_SORT
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001706 tristate "Array-based sort test"
1707 depends on DEBUG_KERNEL || m
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001708 help
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001709 This option enables the self-test function of 'sort()' at boot,
1710 or at module load time.
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001711
1712 If unsure, say N.
1713
Dave Hansen881c5142013-07-01 13:04:44 -07001714config KPROBES_SANITY_TEST
1715 bool "Kprobes sanity tests"
1716 depends on DEBUG_KERNEL
1717 depends on KPROBES
1718 default n
1719 help
1720 This option provides for testing basic kprobes functionality on
1721 boot. A sample kprobe, jprobe and kretprobe are inserted and
1722 verified for functionality.
1723
1724 Say N if you are unsure.
1725
1726config BACKTRACE_SELF_TEST
1727 tristate "Self test for the backtrace code"
1728 depends on DEBUG_KERNEL
1729 default n
1730 help
1731 This option provides a kernel module that can be used to test
1732 the kernel stack backtrace code. This option is not useful
1733 for distributions or general kernels, but only for kernel
1734 developers working on architecture code.
1735
1736 Note that if you want to also test saved backtraces, you will
1737 have to enable STACKTRACE as well.
1738
1739 Say N if you are unsure.
1740
Michel Lespinasse910a7422012-10-08 16:30:39 -07001741config RBTREE_TEST
1742 tristate "Red-Black tree test"
Cody P Schafer7c993e12013-09-11 14:25:19 -07001743 depends on DEBUG_KERNEL
Michel Lespinasse910a7422012-10-08 16:30:39 -07001744 help
1745 A benchmark measuring the performance of the rbtree library.
1746 Also includes rbtree invariant checks.
1747
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001748config INTERVAL_TREE_TEST
1749 tristate "Interval tree test"
Davidlohr Bueso0f789b62017-07-10 15:51:43 -07001750 depends on DEBUG_KERNEL
Chris Wilsona88cc102014-03-17 12:21:54 +00001751 select INTERVAL_TREE
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001752 help
1753 A benchmark measuring the performance of the interval tree library
1754
Greg Thelen623fd802013-11-12 15:08:34 -08001755config PERCPU_TEST
1756 tristate "Per cpu operations test"
1757 depends on m && DEBUG_KERNEL
1758 help
1759 Enable this option to build test module which validates per-cpu
1760 operations.
1761
1762 If unsure, say N.
1763
Dave Hansen881c5142013-07-01 13:04:44 -07001764config ATOMIC64_SELFTEST
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001765 tristate "Perform an atomic64_t self-test"
Dave Hansen881c5142013-07-01 13:04:44 -07001766 help
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001767 Enable this option to test the atomic64_t functions at boot or
1768 at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001769
1770 If unsure, say N.
1771
1772config ASYNC_RAID6_TEST
1773 tristate "Self test for hardware accelerated raid6 recovery"
1774 depends on ASYNC_RAID6_RECOV
1775 select ASYNC_MEMCPY
1776 ---help---
1777 This is a one-shot self test that permutes through the
1778 recovery of all the possible two disk failure scenarios for a
1779 N-disk array. Recovery is performed with the asynchronous
1780 raid6 recovery routines, and will optionally use an offload
1781 engine if one is available.
1782
1783 If unsure, say N.
1784
Andy Shevchenko64d1d772015-02-12 15:02:21 -08001785config TEST_HEXDUMP
1786 tristate "Test functions located in the hexdump module at runtime"
1787
Dave Hansen881c5142013-07-01 13:04:44 -07001788config TEST_STRING_HELPERS
1789 tristate "Test functions located in the string_helpers module at runtime"
1790
1791config TEST_KSTRTOX
1792 tristate "Test kstrto*() family of functions at runtime"
1793
Rasmus Villemoes707cc722015-11-06 16:30:29 -08001794config TEST_PRINTF
1795 tristate "Test printf() family of functions at runtime"
1796
David Decotigny5fd003f2016-02-19 09:24:00 -05001797config TEST_BITMAP
1798 tristate "Test bitmap_*() family of functions at runtime"
1799 default n
1800 help
1801 Enable this option to test the bitmap functions at boot.
1802
1803 If unsure, say N.
1804
Andy Shevchenkocfaff0e2016-05-30 17:40:41 +03001805config TEST_UUID
1806 tristate "Test functions located in the uuid module at runtime"
1807
Rasmus Villemoes455a35a2018-05-08 00:36:28 +02001808config TEST_OVERFLOW
1809 tristate "Test check_*_overflow() functions at runtime"
1810
Thomas Graf7e1e7762014-08-02 11:47:44 +02001811config TEST_RHASHTABLE
Geert Uytterhoeven9d6dbe12015-01-29 15:40:25 +01001812 tristate "Perform selftest on resizable hash table"
Thomas Graf7e1e7762014-08-02 11:47:44 +02001813 default n
1814 help
1815 Enable this option to test the rhashtable functions at boot.
1816
1817 If unsure, say N.
1818
George Spelvin468a9422016-05-26 22:11:51 -04001819config TEST_HASH
1820 tristate "Perform selftest on hash functions"
1821 default n
1822 help
Jason A. Donenfeld2c956a62017-01-08 13:54:00 +01001823 Enable this option to test the kernel's integer (<linux/hash.h>),
1824 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
1825 hash functions on boot (or module load).
George Spelvin468a9422016-05-26 22:11:51 -04001826
1827 This is intended to help people writing architecture-specific
1828 optimized versions. If unsure, say N.
1829
Jiri Pirko44091d22017-02-03 10:29:06 +01001830config TEST_PARMAN
1831 tristate "Perform selftest on priority array manager"
1832 default n
1833 depends on PARMAN
1834 help
1835 Enable this option to test priority array manager on boot
1836 (or module load).
1837
1838 If unsure, say N.
1839
Valentin Rothberg8a6f0b42014-10-13 15:51:38 -07001840config TEST_LKM
Kees Cook93e9ef82014-01-23 15:54:37 -08001841 tristate "Test module loading with 'hello world' module"
1842 default n
1843 depends on m
1844 help
1845 This builds the "test_module" module that emits "Hello, world"
1846 on printk when loaded. It is designed to be used for basic
1847 evaluation of the module loading subsystem (for example when
1848 validating module verification). It lacks any extra dependencies,
1849 and will not normally be loaded by the system unless explicitly
1850 requested by name.
1851
1852 If unsure, say N.
1853
Kees Cook3e2a4c12014-01-23 15:54:38 -08001854config TEST_USER_COPY
1855 tristate "Test user/kernel boundary protections"
1856 default n
1857 depends on m
1858 help
1859 This builds the "test_user_copy" module that runs sanity checks
1860 on the copy_to/from_user infrastructure, making sure basic
1861 user/kernel boundary testing is working. If it fails to load,
1862 a regression has been detected in the user/kernel memory boundary
1863 protections.
1864
1865 If unsure, say N.
1866
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001867config TEST_BPF
1868 tristate "Test BPF filter functionality"
1869 default n
Randy Dunlap98920ba2014-05-13 09:58:44 -07001870 depends on m && NET
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001871 help
1872 This builds the "test_bpf" module that runs various test vectors
1873 against the BPF interpreter or BPF JIT compiler depending on the
1874 current setting. This is in particular useful for BPF JIT compiler
1875 development, but also to run regression tests against changes in
Alexei Starovoitov3c731eb2014-09-26 00:17:07 -07001876 the interpreter code. It also enables test stubs for eBPF maps and
1877 verifier used by user space verifier testsuite.
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001878
1879 If unsure, say N.
1880
Yury Norovdceeb3e2018-02-06 15:38:27 -08001881config FIND_BIT_BENCHMARK
Yury Norov4441fca2017-11-17 15:28:31 -08001882 tristate "Test find_bit functions"
1883 default n
1884 help
1885 This builds the "test_find_bit" module that measure find_*_bit()
1886 functions performance.
1887
1888 If unsure, say N.
1889
Kees Cook0a8adf52014-07-14 14:38:12 -07001890config TEST_FIRMWARE
1891 tristate "Test firmware loading via userspace interface"
1892 default n
1893 depends on FW_LOADER
1894 help
1895 This builds the "test_firmware" module that creates a userspace
1896 interface for testing firmware loading. This can be used to
1897 control the triggering of firmware loading without needing an
1898 actual firmware-using device. The contents can be rechecked by
1899 userspace.
1900
1901 If unsure, say N.
1902
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07001903config TEST_SYSCTL
1904 tristate "sysctl test driver"
1905 default n
1906 depends on PROC_SYSCTL
1907 help
1908 This builds the "test_sysctl" module. This driver enables to test the
1909 proc sysctl interfaces available to drivers safely without affecting
1910 production knobs which might alter system functionality.
1911
1912 If unsure, say N.
1913
David Rileye704f932014-06-16 14:58:32 -07001914config TEST_UDELAY
1915 tristate "udelay test driver"
1916 default n
1917 help
1918 This builds the "udelay_test" module that helps to make sure
1919 that udelay() is working properly.
1920
1921 If unsure, say N.
1922
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02001923config TEST_STATIC_KEYS
1924 tristate "Test static keys"
Jason Baron579e1ac2015-07-30 03:59:44 +00001925 default n
1926 depends on m
1927 help
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02001928 Test the static key interfaces.
Jason Baron579e1ac2015-07-30 03:59:44 +00001929
1930 If unsure, say N.
1931
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07001932config TEST_KMOD
1933 tristate "kmod stress tester"
1934 default n
1935 depends on m
1936 depends on BLOCK && (64BIT || LBDAF) # for XFS, BTRFS
1937 depends on NETDEVICES && NET_CORE && INET # for TUN
1938 select TEST_LKM
1939 select XFS_FS
1940 select TUN
1941 select BTRFS_FS
1942 help
1943 Test the kernel's module loading mechanism: kmod. kmod implements
1944 support to load modules using the Linux kernel's usermode helper.
1945 This test provides a series of tests against kmod.
1946
1947 Although technically you can either build test_kmod as a module or
1948 into the kernel we disallow building it into the kernel since
1949 it stress tests request_module() and this will very likely cause
1950 some issues by taking over precious threads available from other
1951 module load requests, ultimately this could be fatal.
1952
1953 To run tests run:
1954
1955 tools/testing/selftests/kmod/kmod.sh --help
1956
1957 If unsure, say N.
1958
Florian Fainellie4dace32017-09-08 16:15:31 -07001959config TEST_DEBUG_VIRTUAL
1960 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
1961 depends on DEBUG_VIRTUAL
1962 help
1963 Test the kernel's ability to detect incorrect calls to
1964 virt_to_phys() done against the non-linear part of the
1965 kernel's virtual address map.
1966
1967 If unsure, say N.
1968
Vincent Legolld3deafa2018-02-06 15:38:38 -08001969endif # RUNTIME_TESTING_MENU
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001970
1971config MEMTEST
1972 bool "Memtest"
1973 depends on HAVE_MEMBLOCK
1974 ---help---
1975 This option adds a kernel parameter 'memtest', which allows memtest
1976 to be set.
1977 memtest=0, mean disabled; -- default
1978 memtest=1, mean do 1 test pattern;
1979 ...
1980 memtest=17, mean do 17 test patterns.
1981 If you are unsure how to answer this question, answer N.
1982
1983config BUG_ON_DATA_CORRUPTION
1984 bool "Trigger a BUG when data corruption is detected"
1985 select DEBUG_LIST
1986 help
1987 Select this option if the kernel should BUG when it encounters
1988 data corruption in kernel memory structures when they get checked
1989 for validity.
1990
1991 If unsure, say N.
Florian Fainellie4dace32017-09-08 16:15:31 -07001992
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001993source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02001994
1995source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001996
Andrey Ryabininc6d30852016-01-20 15:00:55 -08001997source "lib/Kconfig.ubsan"
1998
Dan Williams21266be2015-11-19 18:19:29 -08001999config ARCH_HAS_DEVMEM_IS_ALLOWED
2000 bool
2001
2002config STRICT_DEVMEM
2003 bool "Filter access to /dev/mem"
Dave Young6b2a65c2016-12-12 16:46:14 -08002004 depends on MMU && DEVMEM
Dan Williams21266be2015-11-19 18:19:29 -08002005 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
Arnd Bergmanna687a532018-03-07 23:30:54 +01002006 default y if PPC || X86 || ARM64
Dan Williams21266be2015-11-19 18:19:29 -08002007 ---help---
2008 If this option is disabled, you allow userspace (root) access to all
2009 of memory, including kernel and userspace memory. Accidental
2010 access to this is obviously disastrous, but specific access can
2011 be used by people debugging the kernel. Note that with PAT support
2012 enabled, even in this case there are restrictions on /dev/mem
2013 use due to the cache aliasing requirements.
2014
Dan Williams90a545e2015-11-23 15:49:03 -08002015 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
2016 file only allows userspace access to PCI space and the BIOS code and
2017 data regions. This is sufficient for dosemu and X and all common
2018 users of /dev/mem.
2019
2020 If in doubt, say Y.
2021
2022config IO_STRICT_DEVMEM
2023 bool "Filter I/O access to /dev/mem"
2024 depends on STRICT_DEVMEM
Dan Williams90a545e2015-11-23 15:49:03 -08002025 ---help---
2026 If this option is disabled, you allow userspace (root) access to all
2027 io-memory regardless of whether a driver is actively using that
2028 range. Accidental access to this is obviously disastrous, but
2029 specific access can be used by people debugging kernel drivers.
2030
Dan Williams21266be2015-11-19 18:19:29 -08002031 If this option is switched on, the /dev/mem file only allows
Dan Williams90a545e2015-11-23 15:49:03 -08002032 userspace access to *idle* io-memory ranges (see /proc/iomem) This
2033 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
2034 if the driver using a given range cannot be disabled.
Dan Williams21266be2015-11-19 18:19:29 -08002035
2036 If in doubt, say Y.