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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
16 parameter printk.time=1. See Documentation/kernel-parameters.txt
Linus Torvalds1da177e2005-04-16 15:20:36 -070017
Alex Elder42a9dc02014-08-06 16:09:01 -070018config MESSAGE_LOGLEVEL_DEFAULT
Mandeep Singh Baines5af5bcb2011-03-22 16:34:23 -070019 int "Default message log level (1-7)"
20 range 1 7
21 default "4"
22 help
23 Default log level for printk statements with no specified priority.
24
25 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
26 that are auditing their logs closely may want to set it to a lower
27 priority.
28
Dave Hansen604ff0d2013-07-01 13:04:49 -070029config BOOT_PRINTK_DELAY
30 bool "Delay each boot printk message by N milliseconds"
31 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
32 help
33 This build option allows you to read kernel boot messages
34 by inserting a short delay after each one. The delay is
35 specified in milliseconds on the kernel command line,
36 using "boot_delay=N".
37
38 It is likely that you would also need to use "lpj=M" to preset
39 the "loops per jiffie" value.
40 See a previous boot log for the "lpj" value to use for your
41 system, and then set "lpj=M" before setting "boot_delay=N".
42 NOTE: Using this option may adversely affect SMP systems.
43 I.e., processors other than the first one may not boot up.
44 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
45 what it believes to be lockup conditions.
46
47config DYNAMIC_DEBUG
48 bool "Enable dynamic printk() support"
49 default n
50 depends on PRINTK
51 depends on DEBUG_FS
52 help
53
54 Compiles debug level messages into the kernel, which would not
55 otherwise be available at runtime. These messages can then be
56 enabled/disabled based on various levels of scope - per source file,
57 function, module, format string, and line number. This mechanism
58 implicitly compiles in all pr_debug() and dev_dbg() calls, which
59 enlarges the kernel text size by about 2%.
60
61 If a source file is compiled with DEBUG flag set, any
62 pr_debug() calls in it are enabled by default, but can be
63 disabled at runtime as below. Note that DEBUG flag is
64 turned on by many CONFIG_*DEBUG* options.
65
66 Usage:
67
68 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
69 which is contained in the 'debugfs' filesystem. Thus, the debugfs
70 filesystem must first be mounted before making use of this feature.
71 We refer the control file as: <debugfs>/dynamic_debug/control. This
72 file contains a list of the debug statements that can be enabled. The
73 format for each line of the file is:
74
75 filename:lineno [module]function flags format
76
77 filename : source file of the debug statement
78 lineno : line number of the debug statement
79 module : module that contains the debug statement
80 function : function that contains the debug statement
81 flags : '=p' means the line is turned 'on' for printing
82 format : the format used for the debug statement
83
84 From a live system:
85
86 nullarbor:~ # cat <debugfs>/dynamic_debug/control
87 # filename:lineno [module]function flags format
88 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
89 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
90 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
91
92 Example usage:
93
94 // enable the message at line 1603 of file svcsock.c
95 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
96 <debugfs>/dynamic_debug/control
97
98 // enable all the messages in file svcsock.c
99 nullarbor:~ # echo -n 'file svcsock.c +p' >
100 <debugfs>/dynamic_debug/control
101
102 // enable all the messages in the NFS server module
103 nullarbor:~ # echo -n 'module nfsd +p' >
104 <debugfs>/dynamic_debug/control
105
106 // enable all 12 messages in the function svc_process()
107 nullarbor:~ # echo -n 'func svc_process +p' >
108 <debugfs>/dynamic_debug/control
109
110 // disable all 12 messages in the function svc_process()
111 nullarbor:~ # echo -n 'func svc_process -p' >
112 <debugfs>/dynamic_debug/control
113
114 See Documentation/dynamic-debug-howto.txt for additional information.
115
116endmenu # "printk and dmesg options"
117
Dave Hansen6dfc0662013-07-01 13:04:46 -0700118menu "Compile-time checks and compiler options"
119
120config DEBUG_INFO
121 bool "Compile the kernel with debug info"
Linus Torvalds12b13832014-02-04 12:20:01 -0800122 depends on DEBUG_KERNEL && !COMPILE_TEST
Dave Hansen6dfc0662013-07-01 13:04:46 -0700123 help
124 If you say Y here the resulting kernel image will include
125 debugging info resulting in a larger kernel image.
126 This adds debug symbols to the kernel and modules (gcc -g), and
127 is needed if you intend to use kernel crashdump or binary object
128 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
129 Say Y here only if you plan to debug the kernel.
130
131 If unsure, say N.
132
133config DEBUG_INFO_REDUCED
134 bool "Reduce debugging information"
135 depends on DEBUG_INFO
136 help
137 If you say Y here gcc is instructed to generate less debugging
138 information for structure types. This means that tools that
139 need full debugging information (like kgdb or systemtap) won't
140 be happy. But if you merely need debugging information to
141 resolve line numbers there is no loss. Advantage is that
142 build directory object sizes shrink dramatically over a full
143 DEBUG_INFO build and compile times are reduced too.
144 Only works with newer gcc versions.
145
Andi Kleen866ced92014-07-30 20:50:18 +0200146config DEBUG_INFO_SPLIT
147 bool "Produce split debuginfo in .dwo files"
148 depends on DEBUG_INFO
149 help
150 Generate debug info into separate .dwo files. This significantly
151 reduces the build directory size for builds with DEBUG_INFO,
152 because it stores the information only once on disk in .dwo
153 files instead of multiple times in object files and executables.
154 In addition the debug information is also compressed.
155
156 Requires recent gcc (4.7+) and recent gdb/binutils.
157 Any tool that packages or reads debug information would need
158 to know about the .dwo files and include them.
159 Incompatible with older versions of ccache.
160
Andi Kleenbfaf2dd2014-07-30 20:50:19 +0200161config DEBUG_INFO_DWARF4
162 bool "Generate dwarf4 debuginfo"
163 depends on DEBUG_INFO
164 help
165 Generate dwarf4 debug info. This requires recent versions
166 of gcc and gdb. It makes the debug information larger.
167 But it significantly improves the success of resolving
168 variables in gdb on optimized code.
169
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800170config GDB_SCRIPTS
171 bool "Provide GDB scripts for kernel debugging"
172 depends on DEBUG_INFO
173 help
174 This creates the required links to GDB helper scripts in the
175 build directory. If you load vmlinux into gdb, the helper
176 scripts will be automatically imported by gdb as well, and
177 additional functions are available to analyze a Linux kernel
178 instance. See Documentation/gdb-kernel-debugging.txt for further
179 details.
180
Jeff Garzikde488442007-10-25 04:06:13 -0400181config ENABLE_WARN_DEPRECATED
182 bool "Enable __deprecated logic"
183 default y
184 help
185 Enable the __deprecated logic in the kernel build.
186 Disable this to suppress the "warning: 'foo' is deprecated
187 (declared at kernel/power/somefile.c:1234)" messages.
188
Andrew Mortoncebc04b2006-08-14 22:43:18 -0700189config ENABLE_MUST_CHECK
190 bool "Enable __must_check logic"
191 default y
192 help
193 Enable the __must_check logic in the kernel build. Disable this to
194 suppress the "warning: ignoring return value of 'foo', declared with
195 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196
Andi Kleen35bb5b12008-02-22 15:15:03 +0100197config FRAME_WARN
198 int "Warn for stack frames larger than (needs gcc 4.4)"
199 range 0 8192
200 default 1024 if !64BIT
201 default 2048 if 64BIT
202 help
203 Tell gcc to warn at build time for stack frames larger than this.
204 Setting this too low will cause a lot of warnings.
205 Setting it to 0 disables the warning.
206 Requires gcc 4.4
207
Randy Dunlap99657c72009-09-18 12:49:22 -0700208config STRIP_ASM_SYMS
209 bool "Strip assembler-generated symbols during link"
210 default n
211 help
212 Strip internal assembler-generated symbols during a link (symbols
213 that look like '.Lxxx') so they don't pollute the output of
214 get_wchan() and suchlike.
215
Andi Kleen1873e872012-03-28 11:51:18 -0700216config READABLE_ASM
217 bool "Generate readable assembler code"
218 depends on DEBUG_KERNEL
219 help
220 Disable some compiler optimizations that tend to generate human unreadable
221 assembler output. This may make the kernel slightly slower, but it helps
222 to keep kernel developers who have to stare a lot at assembler listings
223 sane.
224
Arjan van de Venf71d20e2006-06-28 04:26:45 -0700225config UNUSED_SYMBOLS
226 bool "Enable unused/obsolete exported symbols"
227 default y if X86
228 help
229 Unused but exported symbols make the kernel needlessly bigger. For
230 that reason most of these unused exports will soon be removed. This
231 option is provided temporarily to provide a transition period in case
232 some external kernel module needs one of these symbols anyway. If you
233 encounter such a case in your module, consider if you are actually
234 using the right API. (rationale: since nobody in the kernel is using
235 this in a module, there is a pretty good chance it's actually the
236 wrong interface to use). If you really need the symbol, please send a
237 mail to the linux kernel mailing list mentioning the symbol and why
238 you really need it, and what the merge plan to the mainline kernel for
239 your module is.
240
Joonsoo Kim48c96a32014-12-12 16:56:01 -0800241config PAGE_OWNER
242 bool "Track page owner"
243 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
244 select DEBUG_FS
245 select STACKTRACE
246 select PAGE_EXTENSION
247 help
248 This keeps track of what call chain is the owner of a page, may
249 help to find bare alloc_page(s) leaks. Even if you include this
250 feature on your build, it is disabled in default. You should pass
251 "page_owner=on" to boot parameter in order to enable it. Eats
252 a fair amount of memory if enabled. See tools/vm/page_owner_sort.c
253 for user-space helper.
254
255 If unsure, say N.
256
Don Mullisbf4735a2006-12-10 02:18:37 -0800257config DEBUG_FS
258 bool "Debug Filesystem"
Don Mullisbf4735a2006-12-10 02:18:37 -0800259 help
260 debugfs is a virtual file system that kernel developers use to put
261 debugging files into. Enable this option to be able to read and
262 write to these files.
263
Robert P. J. Dayff543332008-05-20 00:06:00 +0200264 For detailed documentation on the debugfs API, see
265 Documentation/DocBook/filesystems.
266
Don Mullisbf4735a2006-12-10 02:18:37 -0800267 If unsure, say N.
268
269config HEADERS_CHECK
270 bool "Run 'make headers_check' when building vmlinux"
271 depends on !UML
272 help
273 This option will extract the user-visible kernel headers whenever
274 building the kernel, and will run basic sanity checks on them to
275 ensure that exported files do not attempt to include files which
276 were not exported, etc.
277
278 If you're making modifications to header files which are
279 relevant for userspace, say 'Y', and check the headers
280 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
281 your build tree), to make sure they're suitable.
282
Sam Ravnborg91341d42008-01-21 21:31:44 +0100283config DEBUG_SECTION_MISMATCH
284 bool "Enable full Section mismatch analysis"
Sam Ravnborg91341d42008-01-21 21:31:44 +0100285 help
286 The section mismatch analysis checks if there are illegal
287 references from one section to another section.
Michael Wittene809ab02011-04-17 04:08:48 +0000288 During linktime or runtime, some sections are dropped;
289 any use of code/data previously in these sections would
Sam Ravnborg91341d42008-01-21 21:31:44 +0100290 most likely result in an oops.
Michael Wittene809ab02011-04-17 04:08:48 +0000291 In the code, functions and variables are annotated with
Paul Gortmaker0db06282013-06-19 14:53:51 -0400292 __init,, etc. (see the full list in include/linux/init.h),
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100293 which results in the code/data being placed in specific sections.
Michael Wittene809ab02011-04-17 04:08:48 +0000294 The section mismatch analysis is always performed after a full
295 kernel build, and enabling this option causes the following
296 additional steps to occur:
297 - Add the option -fno-inline-functions-called-once to gcc commands.
298 When inlining a function annotated with __init in a non-init
299 function, we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100300 the analysis would not catch the illegal reference.
Michael Wittene809ab02011-04-17 04:08:48 +0000301 This option tells gcc to inline less (but it does result in
302 a larger kernel).
303 - Run the section mismatch analysis for each module/built-in.o file.
304 When we run the section mismatch analysis on vmlinux.o, we
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100305 lose valueble information about where the mismatch was
Sam Ravnborg91341d42008-01-21 21:31:44 +0100306 introduced.
307 Running the analysis for each module/built-in.o file
Michael Wittene809ab02011-04-17 04:08:48 +0000308 tells where the mismatch happens much closer to the
309 source. The drawback is that the same mismatch is
310 reported at least twice.
311 - Enable verbose reporting from modpost in order to help resolve
312 the section mismatches that are reported.
Sam Ravnborg91341d42008-01-21 21:31:44 +0100313
Dave Hansen6dfc0662013-07-01 13:04:46 -0700314#
315# Select this config option from the architecture Kconfig, if it
316# is preferred to always offer frame pointers as a config
317# option on the architecture (regardless of KERNEL_DEBUG):
318#
319config ARCH_WANT_FRAME_POINTERS
320 bool
321 help
322
323config FRAME_POINTER
324 bool "Compile the kernel with frame pointers"
325 depends on DEBUG_KERNEL && \
326 (CRIS || M68K || FRV || UML || \
327 AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \
328 ARCH_WANT_FRAME_POINTERS
329 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
330 help
331 If you say Y here the resulting kernel image will be slightly
332 larger and slower, but it gives very useful debugging information
333 in case of kernel bugs. (precise oopses/stacktraces/warnings)
334
335config DEBUG_FORCE_WEAK_PER_CPU
336 bool "Force weak per-cpu definitions"
337 depends on DEBUG_KERNEL
338 help
339 s390 and alpha require percpu variables in modules to be
340 defined weak to work around addressing range issue which
341 puts the following two restrictions on percpu variable
342 definitions.
343
344 1. percpu symbols must be unique whether static or not
345 2. percpu variables can't be defined inside a function
346
347 To ensure that generic code follows the above rules, this
348 option forces all percpu variables to be defined as weak.
349
350endmenu # "Compiler options"
351
352config MAGIC_SYSRQ
353 bool "Magic SysRq key"
354 depends on !UML
355 help
356 If you say Y here, you will have some control over the system even
357 if the system crashes for example during kernel debugging (e.g., you
358 will be able to flush the buffer cache to disk, reboot the system
359 immediately or dump some status information). This is accomplished
360 by pressing various keys while holding SysRq (Alt+PrintScreen). It
361 also works on a serial console (on PC hardware at least), if you
362 send a BREAK and then within 5 seconds a command keypress. The
363 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
364 unless you really know what this hack does.
365
Ben Hutchings8eaede42013-10-07 01:05:46 +0100366config MAGIC_SYSRQ_DEFAULT_ENABLE
367 hex "Enable magic SysRq key functions by default"
368 depends on MAGIC_SYSRQ
369 default 0x1
370 help
371 Specifies which SysRq key functions are enabled by default.
372 This may be set to 1 or 0 to enable or disable them all, or
373 to a bitmask as described in Documentation/sysrq.txt.
374
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800375config DEBUG_KERNEL
376 bool "Kernel debugging"
377 help
378 Say Y here if you are developing drivers or trying to debug and
379 identify kernel problems.
380
Dave Hansen0610c8a2013-07-01 13:04:43 -0700381menu "Memory Debugging"
David Woodhousea304e1b2007-02-12 00:52:00 -0800382
Dave Hansen0610c8a2013-07-01 13:04:43 -0700383source mm/Kconfig.debug
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800384
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700385config DEBUG_OBJECTS
386 bool "Debug object operations"
387 depends on DEBUG_KERNEL
388 help
389 If you say Y here, additional code will be inserted into the
390 kernel to track the life time of various objects and validate
391 the operations on those objects.
392
393config DEBUG_OBJECTS_SELFTEST
394 bool "Debug objects selftest"
395 depends on DEBUG_OBJECTS
396 help
397 This enables the selftest of the object debug code.
398
399config DEBUG_OBJECTS_FREE
400 bool "Debug objects in freed memory"
401 depends on DEBUG_OBJECTS
402 help
403 This enables checks whether a k/v free operation frees an area
404 which contains an object which has not been deactivated
405 properly. This can make kmalloc/kfree-intensive workloads
406 much slower.
407
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700408config DEBUG_OBJECTS_TIMERS
409 bool "Debug timer objects"
410 depends on DEBUG_OBJECTS
411 help
412 If you say Y here, additional code will be inserted into the
413 timer routines to track the life time of timer objects and
414 validate the timer operations.
415
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900416config DEBUG_OBJECTS_WORK
417 bool "Debug work objects"
418 depends on DEBUG_OBJECTS
419 help
420 If you say Y here, additional code will be inserted into the
421 work queue routines to track the life time of work objects and
422 validate the work operations.
423
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400424config DEBUG_OBJECTS_RCU_HEAD
425 bool "Debug RCU callbacks objects"
Mathieu Desnoyersfc2ecf72011-02-23 09:42:14 -0800426 depends on DEBUG_OBJECTS
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400427 help
428 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
429
Tejun Heoe2852ae2010-10-26 14:23:05 -0700430config DEBUG_OBJECTS_PERCPU_COUNTER
431 bool "Debug percpu counter objects"
432 depends on DEBUG_OBJECTS
433 help
434 If you say Y here, additional code will be inserted into the
435 percpu counter routines to track the life time of percpu counter
436 objects and validate the percpu counter operations.
437
Ingo Molnar3ae70202008-11-26 10:02:00 +0100438config DEBUG_OBJECTS_ENABLE_DEFAULT
439 int "debug_objects bootup default value (0-1)"
440 range 0 1
441 default "1"
442 depends on DEBUG_OBJECTS
443 help
444 Debug objects boot parameter default value
445
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800447 bool "Debug slab memory allocations"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200448 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 help
450 Say Y here to have the kernel do limited verification on memory
451 allocation as well as poisoning memory on free to catch use of freed
452 memory. This can make kmalloc/kfree-intensive workloads much slower.
453
Al Viro871751e2006-03-25 03:06:39 -0800454config DEBUG_SLAB_LEAK
455 bool "Memory leak debugging"
456 depends on DEBUG_SLAB
457
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700458config SLUB_DEBUG_ON
459 bool "SLUB debugging on by default"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200460 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700461 default n
462 help
463 Boot with debugging on by default. SLUB boots by default with
464 the runtime debug capabilities switched off. Enabling this is
465 equivalent to specifying the "slub_debug" parameter on boot.
466 There is no support for more fine grained debug control like
467 possible with slub_debug=xxx. SLUB debugging may be switched
468 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
469 "slub_debug=-".
470
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800471config SLUB_STATS
472 default n
473 bool "Enable SLUB performance statistics"
Christoph Lameterab4d5ed2010-10-05 13:57:26 -0500474 depends on SLUB && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800475 help
476 SLUB statistics are useful to debug SLUBs allocation behavior in
477 order find ways to optimize the allocator. This should never be
478 enabled for production use since keeping statistics slows down
479 the allocator by a few percentage points. The slabinfo command
480 supports the determination of the most active slabs to figure
481 out which slabs are relevant to a particular load.
482 Try running: slabinfo -DA
483
Catalin Marinasb69ec422012-10-08 16:28:11 -0700484config HAVE_DEBUG_KMEMLEAK
485 bool
486
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100487config DEBUG_KMEMLEAK
488 bool "Kernel memory leak detector"
Kees Cook525c1f92013-01-16 18:54:16 -0800489 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
Catalin Marinas79e0d9b2011-04-27 17:06:19 +0100490 select DEBUG_FS
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100491 select STACKTRACE if STACKTRACE_SUPPORT
492 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800493 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100494 help
495 Say Y here if you want to enable the memory leak
496 detector. The memory allocation/freeing is traced in a way
497 similar to the Boehm's conservative garbage collector, the
498 difference being that the orphan objects are not freed but
499 only shown in /sys/kernel/debug/kmemleak. Enabling this
500 feature will introduce an overhead to memory
501 allocations. See Documentation/kmemleak.txt for more
502 details.
503
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100504 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
505 of finding leaks due to the slab objects poisoning.
506
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100507 In order to access the kmemleak file, debugfs needs to be
508 mounted (usually at /sys/kernel/debug).
509
Catalin Marinasa9d90582009-06-25 10:16:11 +0100510config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
511 int "Maximum kmemleak early log entries"
512 depends on DEBUG_KMEMLEAK
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200513 range 200 40000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100514 default 400
515 help
516 Kmemleak must track all the memory allocations to avoid
517 reporting false positives. Since memory may be allocated or
518 freed before kmemleak is initialised, an early log buffer is
519 used to store these actions. If kmemleak reports "early log
520 buffer exceeded", please increase this value.
521
Catalin Marinas0822ee42009-06-11 13:24:14 +0100522config DEBUG_KMEMLEAK_TEST
523 tristate "Simple test for the kernel memory leak detector"
Daniel Baluta97182692011-04-04 15:06:44 -0700524 depends on DEBUG_KMEMLEAK && m
Catalin Marinas0822ee42009-06-11 13:24:14 +0100525 help
Daniel Baluta97182692011-04-04 15:06:44 -0700526 This option enables a module that explicitly leaks memory.
Catalin Marinas0822ee42009-06-11 13:24:14 +0100527
528 If unsure, say N.
529
Jason Baronab0155a2010-07-19 11:54:17 +0100530config DEBUG_KMEMLEAK_DEFAULT_OFF
531 bool "Default kmemleak to off"
532 depends on DEBUG_KMEMLEAK
533 help
534 Say Y here to disable kmemleak by default. It can then be enabled
535 on the command line via kmemleak=on.
536
Dave Hansen0610c8a2013-07-01 13:04:43 -0700537config DEBUG_STACK_USAGE
538 bool "Stack utilization instrumentation"
539 depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG
540 help
541 Enables the display of the minimum amount of free stack which each
542 task has ever had available in the sysrq-T and sysrq-P debug output.
543
544 This option will slow down process creation somewhat.
545
546config DEBUG_VM
547 bool "Debug VM"
548 depends on DEBUG_KERNEL
549 help
550 Enable this to turn on extended checks in the virtual-memory system
551 that may impact performance.
552
553 If unsure, say N.
554
Davidlohr Bueso4f115142014-06-04 16:06:46 -0700555config DEBUG_VM_VMACACHE
556 bool "Debug VMA caching"
557 depends on DEBUG_VM
558 help
559 Enable this to turn on VMA caching debug information. Doing so
560 can cause significant overhead, so only enable it in non-production
561 environments.
562
563 If unsure, say N.
564
Dave Hansen0610c8a2013-07-01 13:04:43 -0700565config DEBUG_VM_RB
566 bool "Debug VM red-black trees"
567 depends on DEBUG_VM
568 help
Davidlohr Buesoa663dad2014-04-18 15:07:22 -0700569 Enable VM red-black tree debugging information and extra validations.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700570
571 If unsure, say N.
572
573config DEBUG_VIRTUAL
574 bool "Debug VM translations"
575 depends on DEBUG_KERNEL && X86
576 help
577 Enable some costly sanity checks in virtual to page code. This can
578 catch mistakes with virt_to_page() and friends.
579
580 If unsure, say N.
581
582config DEBUG_NOMMU_REGIONS
583 bool "Debug the global anon/private NOMMU mapping region tree"
584 depends on DEBUG_KERNEL && !MMU
585 help
586 This option causes the global tree of anonymous and private mapping
587 regions to be regularly checked for invalid topology.
588
589config DEBUG_MEMORY_INIT
590 bool "Debug memory initialisation" if EXPERT
591 default !EXPERT
592 help
593 Enable this for additional checks during memory initialisation.
594 The sanity checks verify aspects of the VM such as the memory model
595 and other information provided by the architecture. Verbose
596 information will be printed at KERN_DEBUG loglevel depending
597 on the mminit_loglevel= command-line option.
598
599 If unsure, say Y
600
601config MEMORY_NOTIFIER_ERROR_INJECT
602 tristate "Memory hotplug notifier error injection module"
603 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
604 help
605 This option provides the ability to inject artificial errors to
606 memory hotplug notifier chain callbacks. It is controlled through
607 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
608
609 If the notifier call chain should be failed with some events
610 notified, write the error code to "actions/<notifier event>/error".
611
612 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
613
614 # cd /sys/kernel/debug/notifier-error-inject/memory
615 # echo -12 > actions/MEM_GOING_OFFLINE/error
616 # echo offline > /sys/devices/system/memory/memoryXXX/state
617 bash: echo: write error: Cannot allocate memory
618
619 To compile this code as a module, choose M here: the module will
620 be called memory-notifier-error-inject.
621
622 If unsure, say N.
623
624config DEBUG_PER_CPU_MAPS
625 bool "Debug access to per_cpu maps"
626 depends on DEBUG_KERNEL
627 depends on SMP
628 help
629 Say Y to verify that the per_cpu map being accessed has
630 been set up. This adds a fair amount of code to kernel memory
631 and decreases performance.
632
633 Say N if unsure.
634
635config DEBUG_HIGHMEM
636 bool "Highmem debugging"
637 depends on DEBUG_KERNEL && HIGHMEM
638 help
Geert Uytterhoevenb1357c92014-04-14 18:55:50 +0200639 This option enables additional error checking for high memory
640 systems. Disable for production systems.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700641
642config HAVE_DEBUG_STACKOVERFLOW
643 bool
644
645config DEBUG_STACKOVERFLOW
646 bool "Check for stack overflows"
647 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
648 ---help---
649 Say Y here if you want to check for overflows of kernel, IRQ
Borislav Petkovedb0ec02015-01-25 19:50:34 +0100650 and exception stacks (if your architecture uses them). This
Dave Hansen0610c8a2013-07-01 13:04:43 -0700651 option will show detailed messages if free stack space drops
652 below a certain limit.
653
654 These kinds of bugs usually occur when call-chains in the
655 kernel get too deep, especially when interrupts are
656 involved.
657
658 Use this in cases where you see apparently random memory
659 corruption, especially if it appears in 'struct thread_info'
660
661 If in doubt, say "N".
662
663source "lib/Kconfig.kmemcheck"
664
Andrey Ryabinin0b24bec2015-02-13 14:39:17 -0800665source "lib/Kconfig.kasan"
666
Dave Hansen0610c8a2013-07-01 13:04:43 -0700667endmenu # "Memory Debugging"
668
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669config DEBUG_SHIRQ
670 bool "Debug shared IRQ handlers"
Martin Schwidefsky0244ad02013-08-30 09:39:53 +0200671 depends on DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 help
673 Enable this to generate a spurious interrupt as soon as a shared
674 interrupt handler is registered, and just before one is deregistered.
675 Drivers ought to be able to handle interrupts coming in at those
676 points; some don't and need to be caught.
677
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700678menu "Debug Lockups and Hangs"
679
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680config LOCKUP_DETECTOR
681 bool "Detect Hard and Soft Lockups"
682 depends on DEBUG_KERNEL && !S390
683 help
684 Say Y here to enable the kernel to act as a watchdog to detect
685 hard and soft lockups.
686
687 Softlockups are bugs that cause the kernel to loop in kernel
688 mode for more than 20 seconds, without giving other tasks a
689 chance to run. The current stack trace is displayed upon
690 detection and the system will stay locked up.
691
692 Hardlockups are bugs that cause the CPU to loop in kernel mode
693 for more than 10 seconds, without letting other interrupts have a
694 chance to run. The current stack trace is displayed upon detection
695 and the system will stay locked up.
696
697 The overhead should be minimal. A periodic hrtimer runs to
698 generate interrupts and kick the watchdog task every 4 seconds.
699 An NMI is generated every 10 seconds or so to check for hardlockups.
700
701 The frequency of hrtimer and NMI events and the soft and hard lockup
702 thresholds can be controlled through the sysctl watchdog_thresh.
703
704config HARDLOCKUP_DETECTOR
705 def_bool y
706 depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG
707 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
708
709config BOOTPARAM_HARDLOCKUP_PANIC
710 bool "Panic (Reboot) On Hard Lockups"
711 depends on HARDLOCKUP_DETECTOR
712 help
713 Say Y here to enable the kernel to panic on "hard lockups",
714 which are bugs that cause the kernel to loop in kernel
715 mode with interrupts disabled for more than 10 seconds (configurable
716 using the watchdog_thresh sysctl).
717
718 Say N if unsure.
719
720config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
721 int
722 depends on HARDLOCKUP_DETECTOR
723 range 0 1
724 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
725 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
726
727config BOOTPARAM_SOFTLOCKUP_PANIC
728 bool "Panic (Reboot) On Soft Lockups"
729 depends on LOCKUP_DETECTOR
730 help
731 Say Y here to enable the kernel to panic on "soft lockups",
732 which are bugs that cause the kernel to loop in kernel
733 mode for more than 20 seconds (configurable using the watchdog_thresh
734 sysctl), without giving other tasks a chance to run.
735
736 The panic can be used in combination with panic_timeout,
737 to cause the system to reboot automatically after a
738 lockup has been detected. This feature is useful for
739 high-availability systems that have uptime guarantees and
740 where a lockup must be resolved ASAP.
741
Ingo Molnar8637c092006-07-03 00:24:38 -0700742 Say N if unsure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743
744config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
745 int
746 depends on LOCKUP_DETECTOR
747 range 0 1
748 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
749 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700750
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751config DETECT_HUNG_TASK
752 bool "Detect Hung Tasks"
753 depends on DEBUG_KERNEL
754 default LOCKUP_DETECTOR
755 help
756 Say Y here to enable the kernel to detect "hung tasks",
757 which are bugs that cause the task to be stuck in
758 uninterruptible "D" state indefinitiley.
759
760 When a hung task is detected, the kernel will print the
761 current stack trace (which you should report), but the
762 task will stay in uninterruptible state. If lockdep is
763 enabled then all held locks will also be reported. This
764 feature has negligible overhead.
765
766config DEFAULT_HUNG_TASK_TIMEOUT
767 int "Default timeout for hung task detection (in seconds)"
768 depends on DETECT_HUNG_TASK
769 default 120
770 help
771 This option controls the default timeout (in seconds) used
772 to determine when a task has become non-responsive and should
773 be considered hung.
774
775 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
776 sysctl or by writing a value to
777 /proc/sys/kernel/hung_task_timeout_secs.
778
Ingo Molnar408894e2006-01-09 15:59:20 -0800779 A timeout of 0 disables the check. The default is two minutes.
780 Keeping the default should be fine in most cases.
781
782config BOOTPARAM_HUNG_TASK_PANIC
783 bool "Panic (Reboot) On Hung Tasks"
784 depends on DETECT_HUNG_TASK
Tim Chencca57c52006-04-18 22:21:47 -0700785 help
Ingo Molnar408894e2006-01-09 15:59:20 -0800786 Say Y here to enable the kernel to panic on "hung tasks",
787 which are bugs that cause the kernel to leave a task stuck
788 in uninterruptible "D" state.
789
790 The panic can be used in combination with panic_timeout,
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700791 to cause the system to reboot automatically after a
792 hung task has been detected. This feature is useful for
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700793 high-availability systems that have uptime guarantees and
794 where a hung tasks must be resolved ASAP.
795
796 Say N if unsure.
797
798config BOOTPARAM_HUNG_TASK_PANIC_VALUE
799 int
800 depends on DETECT_HUNG_TASK
801 range 0 1
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100802 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 default 1 if BOOTPARAM_HUNG_TASK_PANIC
804
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700805endmenu # "Debug lockups and hangs"
806
807config PANIC_ON_OOPS
808 bool "Panic on Oops"
809 help
810 Say Y here to enable the kernel to panic when it oopses. This
811 has the same effect as setting oops=panic on the kernel command
812 line.
813
814 This feature is useful to ensure that the kernel does not do
815 anything erroneous after an oops which could result in data
816 corruption or other issues.
817
818 Say N if unsure.
819
820config PANIC_ON_OOPS_VALUE
821 int
822 range 0 1
823 default 0 if !PANIC_ON_OOPS
824 default 1 if PANIC_ON_OOPS
825
Jason Baron5800dc32013-11-25 23:23:04 +0000826config PANIC_TIMEOUT
827 int "panic timeout"
828 default 0
829 help
830 Set the timeout value (in seconds) until a reboot occurs when the
831 the kernel panics. If n = 0, then we wait forever. A timeout
832 value n > 0 will wait n seconds before rebooting, while a timeout
833 value n < 0 will reboot immediately.
834
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835config SCHED_DEBUG
836 bool "Collect scheduler debugging info"
837 depends on DEBUG_KERNEL && PROC_FS
838 default y
839 help
840 If you say Y here, the /proc/sched_debug file will be provided
841 that can help debug the scheduler. The runtime overhead of this
842 option is minimal.
843
Naveen N. Raof6db8342015-06-25 23:53:37 +0530844config SCHED_INFO
845 bool
846 default n
847
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848config SCHEDSTATS
849 bool "Collect scheduler statistics"
850 depends on DEBUG_KERNEL && PROC_FS
Naveen N. Raof6db8342015-06-25 23:53:37 +0530851 select SCHED_INFO
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 help
853 If you say Y here, additional code will be inserted into the
854 scheduler and related routines to collect statistics about
855 scheduler behavior and provide them in /proc/schedstat. These
856 stats may be useful for both tuning and debugging the scheduler
857 If you aren't debugging the scheduler or trying to tune a specific
858 application, you can say N to avoid the very slight overhead
859 this adds.
860
Aaron Tomlin0d9e2632014-09-12 14:16:19 +0100861config SCHED_STACK_END_CHECK
862 bool "Detect stack corruption on calls to schedule()"
863 depends on DEBUG_KERNEL
864 default n
865 help
866 This option checks for a stack overrun on calls to schedule().
867 If the stack end location is found to be over written always panic as
868 the content of the corrupted region can no longer be trusted.
869 This is to ensure no erroneous behaviour occurs which could result in
870 data corruption or a sporadic crash at a later stage once the region
871 is examined. The runtime overhead introduced is minimal.
872
John Stultz3c17ad12015-03-11 21:16:32 -0700873config DEBUG_TIMEKEEPING
874 bool "Enable extra timekeeping sanity checking"
875 help
876 This option will enable additional timekeeping sanity checks
877 which may be helpful when diagnosing issues where timekeeping
878 problems are suspected.
879
880 This may include checks in the timekeeping hotpaths, so this
881 option may have a (very small) performance impact to some
882 workloads.
883
884 If unsure, say N.
885
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886config TIMER_STATS
887 bool "Collect kernel timers statistics"
888 depends on DEBUG_KERNEL && PROC_FS
889 help
890 If you say Y here, additional code will be inserted into the
891 timer routines to collect statistics about kernel timers being
892 reprogrammed. The statistics can be read from /proc/timer_stats.
893 The statistics collection is started by writing 1 to /proc/timer_stats,
894 writing 0 stops it. This feature is useful to collect information
895 about timer usage patterns in kernel and userspace. This feature
896 is lightweight if enabled in the kernel config but not activated
897 (it defaults to deactivated on bootup and will only be activated
898 if some application like powertop activates it explicitly).
899
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900config DEBUG_PREEMPT
901 bool "Debug preemptible kernel"
Kumar Gala01deab92009-10-16 07:21:39 +0000902 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903 default y
904 help
905 If you say Y here then the kernel will use a debug variant of the
906 commonly used smp_processor_id() function and will print warnings
907 if kernel code uses it in a preemption-unsafe way. Also, the kernel
908 will detect preemption count underflows.
909
Dave Hansen9eade162013-07-01 13:04:47 -0700910menu "Lock Debugging (spinlocks, mutexes, etc...)"
911
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700912config DEBUG_RT_MUTEXES
913 bool "RT Mutex debugging, deadlock detection"
914 depends on DEBUG_KERNEL && RT_MUTEXES
915 help
916 This allows rt mutex semantics violations and rt mutex related
917 deadlocks (lockups) to be detected and reported automatically.
918
Thomas Gleixner61a87122006-06-27 02:54:56 -0700919config RT_MUTEX_TESTER
920 bool "Built-in scriptable tester for rt-mutexes"
Thomas Gleixner6cc620b2014-06-22 00:03:21 +0200921 depends on DEBUG_KERNEL && RT_MUTEXES && BROKEN
Thomas Gleixner61a87122006-06-27 02:54:56 -0700922 help
923 This option enables a rt-mutex tester.
924
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700926 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +0530928 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929 help
930 Say Y here and build SMP to catch missing spinlock initialization
931 and certain other kinds of spinlock errors commonly made. This is
932 best used in conjunction with the NMI watchdog so that spinlock
933 deadlocks are also debuggable.
934
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700935config DEBUG_MUTEXES
936 bool "Mutex debugging: basic checks"
937 depends on DEBUG_KERNEL
938 help
939 This feature allows mutex semantics violations to be detected and
940 reported.
941
Daniel Vetter23010022013-06-20 13:31:17 +0200942config DEBUG_WW_MUTEX_SLOWPATH
943 bool "Wait/wound mutex debugging: Slowpath testing"
944 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
945 select DEBUG_LOCK_ALLOC
946 select DEBUG_SPINLOCK
947 select DEBUG_MUTEXES
948 help
949 This feature enables slowpath testing for w/w mutex users by
950 injecting additional -EDEADLK wound/backoff cases. Together with
951 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
952 will test all possible w/w mutex interface abuse with the
953 exception of simply not acquiring all the required locks.
Rob Clark4d692372014-08-27 11:19:26 -0400954 Note that this feature can introduce significant overhead, so
955 it really should not be enabled in a production or distro kernel,
956 even a debug kernel. If you are a driver writer, enable it. If
957 you are a distro, do not.
Daniel Vetter23010022013-06-20 13:31:17 +0200958
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700959config DEBUG_LOCK_ALLOC
960 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700961 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700962 select DEBUG_SPINLOCK
963 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700964 select LOCKDEP
965 help
966 This feature will check whether any held lock (spinlock, rwlock,
967 mutex or rwsem) is incorrectly freed by the kernel, via any of the
968 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
969 vfree(), etc.), whether a live lock is incorrectly reinitialized via
970 spin_lock_init()/mutex_init()/etc., or whether there is any lock
971 held during task exit.
972
973config PROVE_LOCKING
974 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700975 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700976 select LOCKDEP
977 select DEBUG_SPINLOCK
978 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700979 select DEBUG_LOCK_ALLOC
Steven Rostedt46b93b72010-08-31 16:35:20 -0400980 select TRACE_IRQFLAGS
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700981 default n
982 help
983 This feature enables the kernel to prove that all locking
984 that occurs in the kernel runtime is mathematically
985 correct: that under no circumstance could an arbitrary (and
986 not yet triggered) combination of observed locking
987 sequences (on an arbitrary number of CPUs, running an
988 arbitrary number of tasks and interrupt contexts) cause a
989 deadlock.
990
991 In short, this feature enables the kernel to report locking
992 related deadlocks before they actually occur.
993
994 The proof does not depend on how hard and complex a
995 deadlock scenario would be to trigger: how many
996 participant CPUs, tasks and irq-contexts would be needed
997 for it to trigger. The proof also does not depend on
998 timing: if a race and a resulting deadlock is possible
999 theoretically (no matter how unlikely the race scenario
1000 is), it will be proven so and will immediately be
1001 reported by the kernel (once the event is observed that
1002 makes the deadlock theoretically possible).
1003
1004 If a deadlock is impossible (i.e. the locking rules, as
1005 observed by the kernel, are mathematically correct), the
1006 kernel reports nothing.
1007
1008 NOTE: this feature can also be enabled for rwlocks, mutexes
1009 and rwsems - in which case all dependencies between these
1010 different locking variants are observed and mapped too, and
1011 the proof of observed correctness is also maintained for an
1012 arbitrary combination of these separate locking variants.
1013
Davidlohr Bueso214e0ae2014-07-30 13:41:55 -07001014 For more details, see Documentation/locking/lockdep-design.txt.
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001015
1016config LOCKDEP
1017 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -07001018 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001019 select STACKTRACE
Chen Gangdf2e1ef2014-06-23 13:22:04 -07001020 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC && !SCORE
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001021 select KALLSYMS
1022 select KALLSYMS_ALL
1023
Peter Zijlstraf20786f2007-07-19 01:48:56 -07001024config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -07001025 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -07001026 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1027 select LOCKDEP
1028 select DEBUG_SPINLOCK
1029 select DEBUG_MUTEXES
1030 select DEBUG_LOCK_ALLOC
1031 default n
1032 help
1033 This feature enables tracking lock contention points
1034
Davidlohr Bueso214e0ae2014-07-30 13:41:55 -07001035 For more details, see Documentation/locking/lockstat.txt
Peter Zijlstraa560aa42007-10-07 00:24:33 -07001036
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +01001037 This also enables lock events required by "perf lock",
1038 subcommand of perf.
1039 If you want to use "perf lock", you also need to turn on
1040 CONFIG_EVENT_TRACING.
Hitoshi Mitake84c6f882010-02-04 16:08:15 +09001041
1042 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +01001043 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
Hitoshi Mitake84c6f882010-02-04 16:08:15 +09001044
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001045config DEBUG_LOCKDEP
1046 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -07001047 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001048 help
1049 If you say Y here, the lock dependency engine will do
1050 additional runtime checks to debug itself, at the price
1051 of more runtime overhead.
1052
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001053config DEBUG_ATOMIC_SLEEP
1054 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +02001055 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001056 depends on DEBUG_KERNEL
1057 help
1058 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001059 noisy if they are called inside atomic sections: when a spinlock is
1060 held, inside an rcu read side critical section, inside preempt disabled
1061 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -07001062
Ingo Molnarcae2ed92006-07-03 00:24:48 -07001063config DEBUG_LOCKING_API_SELFTESTS
1064 bool "Locking API boot-time self-tests"
1065 depends on DEBUG_KERNEL
1066 help
1067 Say Y here if you want the kernel to run a short self-test during
1068 bootup. The self-test checks whether common types of locking bugs
1069 are detected by debugging mechanisms or not. (if you disable
1070 lock debugging then those bugs wont be detected of course.)
1071 The following locking APIs are covered: spinlocks, rwlocks,
1072 mutexes and rwsems.
1073
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001074config LOCK_TORTURE_TEST
1075 tristate "torture tests for locking"
1076 depends on DEBUG_KERNEL
1077 select TORTURE_TEST
1078 default n
1079 help
1080 This option provides a kernel module that runs torture tests
1081 on kernel locking primitives. The kernel module may be built
1082 after the fact on the running kernel to be tested, if desired.
1083
1084 Say Y here if you want kernel locking-primitive torture tests
1085 to be built into the kernel.
1086 Say M if you want these torture tests to build as a module.
1087 Say N if you are unsure.
1088
Dave Hansen9eade162013-07-01 13:04:47 -07001089endmenu # lock debugging
1090
1091config TRACE_IRQFLAGS
1092 bool
1093 help
1094 Enables hooks to interrupt enabling and disabling for
1095 either tracing or lock debugging.
1096
Ingo Molnar8637c092006-07-03 00:24:38 -07001097config STACKTRACE
Dave Jones0c38e1f2014-08-29 15:18:35 -07001098 bool "Stack backtrace support"
Ingo Molnar8637c092006-07-03 00:24:38 -07001099 depends on STACKTRACE_SUPPORT
Dave Jones0c38e1f2014-08-29 15:18:35 -07001100 help
1101 This option causes the kernel to create a /proc/pid/stack for
1102 every process, showing its current stack trace.
1103 It is also used by various kernel debugging features that require
1104 stack trace generation.
Ingo Molnar8637c092006-07-03 00:24:38 -07001105
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106config DEBUG_KOBJECT
1107 bool "kobject debugging"
1108 depends on DEBUG_KERNEL
1109 help
1110 If you say Y here, some extra kobject debugging messages will be sent
1111 to the syslog.
1112
Russell Kingc817a672013-06-27 15:06:14 +01001113config DEBUG_KOBJECT_RELEASE
1114 bool "kobject release debugging"
Linus Torvalds2a999aa2013-10-29 08:33:36 -07001115 depends on DEBUG_OBJECTS_TIMERS
Russell Kingc817a672013-06-27 15:06:14 +01001116 help
1117 kobjects are reference counted objects. This means that their
1118 last reference count put is not predictable, and the kobject can
1119 live on past the point at which a driver decides to drop it's
1120 initial reference to the kobject gained on allocation. An
1121 example of this would be a struct device which has just been
1122 unregistered.
1123
1124 However, some buggy drivers assume that after such an operation,
1125 the memory backing the kobject can be immediately freed. This
1126 goes completely against the principles of a refcounted object.
1127
1128 If you say Y here, the kernel will delay the release of kobjects
1129 on the last reference count to improve the visibility of this
1130 kind of kobject release bug.
1131
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001132config HAVE_DEBUG_BUGVERBOSE
1133 bool
1134
Linus Torvalds1da177e2005-04-16 15:20:36 -07001135config DEBUG_BUGVERBOSE
David Rientjes6a108a12011-01-20 14:44:16 -08001136 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001137 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
Alexey Dobriyan8420e7e2009-12-14 18:00:25 -08001138 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139 help
1140 Say Y here to make BUG() panics output the file name and line number
1141 of the BUG call as well as the EIP and oops trace. This aids
1142 debugging but costs about 70-100K of memory.
1143
Dave Jones199a9af2006-09-29 01:59:00 -07001144config DEBUG_LIST
1145 bool "Debug linked list manipulation"
1146 depends on DEBUG_KERNEL
1147 help
1148 Enable this to turn on extended checks in the linked-list
1149 walking routines.
1150
1151 If unsure, say N.
1152
Dan Streetmanb8cfff62014-06-04 16:11:54 -07001153config DEBUG_PI_LIST
1154 bool "Debug priority linked list manipulation"
1155 depends on DEBUG_KERNEL
1156 help
1157 Enable this to turn on extended checks in the priority-ordered
1158 linked-list (plist) walking routines. This checks the entire
1159 list multiple times during each manipulation.
1160
1161 If unsure, say N.
1162
Jens Axboed6ec0842007-10-22 20:01:06 +02001163config DEBUG_SG
1164 bool "Debug SG table operations"
1165 depends on DEBUG_KERNEL
1166 help
1167 Enable this to turn on checks on scatter-gather tables. This can
1168 help find problems with drivers that do not properly initialize
1169 their sg tables.
1170
1171 If unsure, say N.
1172
Arjan van de Ven1b2439d2008-08-15 15:29:38 -07001173config DEBUG_NOTIFIERS
1174 bool "Debug notifier call chains"
1175 depends on DEBUG_KERNEL
1176 help
1177 Enable this to turn on sanity checking for notifier call chains.
1178 This is most useful for kernel developers to make sure that
1179 modules properly unregister themselves from notifier chains.
1180 This is a relatively cheap check but if you care about maximum
1181 performance, say N.
1182
David Howellse0e81732009-09-02 09:13:40 +01001183config DEBUG_CREDENTIALS
1184 bool "Debug credential management"
1185 depends on DEBUG_KERNEL
1186 help
1187 Enable this to turn on some debug checking for credential
1188 management. The additional code keeps track of the number of
1189 pointers from task_structs to any given cred struct, and checks to
1190 see that this number never exceeds the usage count of the cred
1191 struct.
1192
1193 Furthermore, if SELinux is enabled, this also checks that the
1194 security pointer in the cred struct is never seen to be invalid.
1195
1196 If unsure, say N.
1197
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001198menu "RCU Debugging"
1199
1200config PROVE_RCU
Paul E. McKenney9bae6592015-01-18 18:01:21 -08001201 def_bool PROVE_LOCKING
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001202
1203config PROVE_RCU_REPEATEDLY
1204 bool "RCU debugging: don't disable PROVE_RCU on first splat"
1205 depends on PROVE_RCU
1206 default n
1207 help
1208 By itself, PROVE_RCU will disable checking upon issuing the
1209 first warning (or "splat"). This feature prevents such
1210 disabling, allowing multiple RCU-lockdep warnings to be printed
1211 on a single reboot.
1212
1213 Say Y to allow multiple RCU-lockdep warnings per boot.
1214
1215 Say N if you are unsure.
1216
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001217config SPARSE_RCU_POINTER
1218 bool "RCU debugging: sparse-based checks for pointer usage"
1219 default n
1220 help
1221 This feature enables the __rcu sparse annotation for
1222 RCU-protected pointers. This annotation will cause sparse
1223 to flag any non-RCU used of annotated pointers. This can be
1224 helpful when debugging RCU usage. Please note that this feature
1225 is not intended to enforce code cleanliness; it is instead merely
1226 a debugging aid.
1227
1228 Say Y to make sparse flag questionable use of RCU-protected pointers
1229
1230 Say N if you are unsure.
1231
Paul E. McKenney51b11302014-01-27 11:49:39 -08001232config TORTURE_TEST
1233 tristate
1234 default n
1235
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001236config RCU_TORTURE_TEST
1237 tristate "torture tests for RCU"
1238 depends on DEBUG_KERNEL
Paul E. McKenney51b11302014-01-27 11:49:39 -08001239 select TORTURE_TEST
Pranith Kumar83fe27e2014-12-05 11:24:45 -05001240 select SRCU
Paul E. McKenney82d0f4c2015-04-20 05:42:50 -07001241 select TASKS_RCU
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001242 default n
1243 help
1244 This option provides a kernel module that runs torture tests
1245 on the RCU infrastructure. The kernel module may be built
1246 after the fact on the running kernel to be tested, if desired.
1247
Paul E. McKenney31a72bc2008-06-18 09:26:49 -07001248 Say Y here if you want RCU torture tests to be built into
1249 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001250 Say M if you want the RCU torture tests to build as a module.
1251 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -07001252
Paul E. McKenney31a72bc2008-06-18 09:26:49 -07001253config RCU_TORTURE_TEST_RUNNABLE
1254 bool "torture tests for RCU runnable by default"
1255 depends on RCU_TORTURE_TEST = y
1256 default n
1257 help
1258 This option provides a way to build the RCU torture tests
1259 directly into the kernel without them starting up at boot
1260 time. You can use /proc/sys/kernel/rcutorture_runnable
1261 to manually override this setting. This /proc file is
1262 available only when the RCU torture tests have been built
1263 into the kernel.
1264
1265 Say Y here if you want the RCU torture tests to start during
1266 boot (you probably don't).
1267 Say N here if you want the RCU torture tests to start only
1268 after being manually enabled via /proc.
1269
Paul E. McKenney0f41c0d2015-03-10 18:33:20 -07001270config RCU_TORTURE_TEST_SLOW_PREINIT
1271 bool "Slow down RCU grace-period pre-initialization to expose races"
1272 depends on RCU_TORTURE_TEST
1273 help
1274 This option delays grace-period pre-initialization (the
1275 propagation of CPU-hotplug changes up the rcu_node combining
1276 tree) for a few jiffies between initializing each pair of
1277 consecutive rcu_node structures. This helps to expose races
1278 involving grace-period pre-initialization, in other words, it
1279 makes your kernel less stable. It can also greatly increase
1280 grace-period latency, especially on systems with large numbers
1281 of CPUs. This is useful when torture-testing RCU, but in
1282 almost no other circumstance.
1283
1284 Say Y here if you want your system to crash and hang more often.
1285 Say N if you want a sane system.
1286
1287config RCU_TORTURE_TEST_SLOW_PREINIT_DELAY
1288 int "How much to slow down RCU grace-period pre-initialization"
1289 range 0 5
1290 default 3
1291 depends on RCU_TORTURE_TEST_SLOW_PREINIT
1292 help
1293 This option specifies the number of jiffies to wait between
1294 each rcu_node structure pre-initialization step.
1295
Paul E. McKenney37745d22015-01-22 18:24:08 -08001296config RCU_TORTURE_TEST_SLOW_INIT
1297 bool "Slow down RCU grace-period initialization to expose races"
1298 depends on RCU_TORTURE_TEST
1299 help
Paul E. McKenney0f41c0d2015-03-10 18:33:20 -07001300 This option delays grace-period initialization for a few
1301 jiffies between initializing each pair of consecutive
Paul E. McKenney37745d22015-01-22 18:24:08 -08001302 rcu_node structures. This helps to expose races involving
1303 grace-period initialization, in other words, it makes your
1304 kernel less stable. It can also greatly increase grace-period
1305 latency, especially on systems with large numbers of CPUs.
1306 This is useful when torture-testing RCU, but in almost no
1307 other circumstance.
1308
1309 Say Y here if you want your system to crash and hang more often.
1310 Say N if you want a sane system.
1311
1312config RCU_TORTURE_TEST_SLOW_INIT_DELAY
1313 int "How much to slow down RCU grace-period initialization"
1314 range 0 5
Paul E. McKenney186bea52015-01-29 16:37:19 -08001315 default 3
Paul E. McKenney8d7dc922015-04-14 19:33:59 -07001316 depends on RCU_TORTURE_TEST_SLOW_INIT
Paul E. McKenney37745d22015-01-22 18:24:08 -08001317 help
1318 This option specifies the number of jiffies to wait between
1319 each rcu_node structure initialization.
1320
Paul E. McKenney0f41c0d2015-03-10 18:33:20 -07001321config RCU_TORTURE_TEST_SLOW_CLEANUP
1322 bool "Slow down RCU grace-period cleanup to expose races"
1323 depends on RCU_TORTURE_TEST
1324 help
1325 This option delays grace-period cleanup for a few jiffies
1326 between cleaning up each pair of consecutive rcu_node
1327 structures. This helps to expose races involving grace-period
1328 cleanup, in other words, it makes your kernel less stable.
1329 It can also greatly increase grace-period latency, especially
1330 on systems with large numbers of CPUs. This is useful when
1331 torture-testing RCU, but in almost no other circumstance.
1332
1333 Say Y here if you want your system to crash and hang more often.
1334 Say N if you want a sane system.
1335
1336config RCU_TORTURE_TEST_SLOW_CLEANUP_DELAY
1337 int "How much to slow down RCU grace-period cleanup"
1338 range 0 5
1339 default 3
1340 depends on RCU_TORTURE_TEST_SLOW_CLEANUP
1341 help
1342 This option specifies the number of jiffies to wait between
1343 each rcu_node structure cleanup operation.
1344
Paul E. McKenneyb1637602010-06-02 16:21:38 -07001345config RCU_CPU_STALL_TIMEOUT
1346 int "RCU CPU stall timeout in seconds"
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -07001347 depends on RCU_STALL_COMMON
Paul E. McKenneyb1637602010-06-02 16:21:38 -07001348 range 3 300
Paul E. McKenneyc8960542012-10-25 17:59:23 -07001349 default 21
Paul E. McKenneyb1637602010-06-02 16:21:38 -07001350 help
1351 If a given RCU grace period extends more than the specified
1352 number of seconds, a CPU stall warning is printed. If the
1353 RCU grace period persists, additional CPU stall warnings are
1354 printed at more widely spaced intervals.
1355
Paul E. McKenneya858af22012-01-16 13:29:10 -08001356config RCU_CPU_STALL_INFO
1357 bool "Print additional diagnostics on RCU CPU stall"
Pranith Kumar28f65692014-09-22 14:00:48 -04001358 depends on (TREE_RCU || PREEMPT_RCU) && DEBUG_KERNEL
Paul E. McKenney68158fe2014-12-08 07:41:31 -08001359 default y
Paul E. McKenneya858af22012-01-16 13:29:10 -08001360 help
1361 For each stalled CPU that is aware of the current RCU grace
1362 period, print out additional per-CPU diagnostic information
1363 regarding scheduling-clock ticks, idle state, and,
1364 for RCU_FAST_NO_HZ kernels, idle-entry state.
1365
1366 Say N if you are unsure.
1367
1368 Say Y if you want to enable such diagnostics.
1369
Paul E. McKenney5c8806a2012-01-06 15:10:44 -08001370config RCU_TRACE
1371 bool "Enable tracing for RCU"
1372 depends on DEBUG_KERNEL
Paul E. McKenney52494532012-11-14 16:26:40 -08001373 select TRACE_CLOCK
Paul E. McKenney5c8806a2012-01-06 15:10:44 -08001374 help
1375 This option provides tracing in RCU which presents stats
1376 in debugfs for debugging RCU implementation.
1377
1378 Say Y here if you want to enable RCU tracing
1379 Say N if you are unsure.
1380
Paul E. McKenney1ce46ee2015-05-05 23:04:22 -07001381config RCU_EQS_DEBUG
1382 bool "Use this when adding any sort of NO_HZ support to your arch"
1383 depends on DEBUG_KERNEL
1384 help
1385 This option provides consistency checks in RCU's handling of
1386 NO_HZ. These checks have proven quite helpful in detecting
1387 bugs in arch-specific NO_HZ code.
1388
1389 Say N here if you need ultimate kernel/user switch latencies
1390 Say Y if you are unsure
1391
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001392endmenu # "RCU Debugging"
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
Akinobu Mita8d438282012-07-30 14:43:02 -07001421config NOTIFIER_ERROR_INJECTION
1422 tristate "Notifier error injection"
1423 depends on DEBUG_KERNEL
1424 select DEBUG_FS
1425 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001426 This option provides the ability to inject artificial errors to
Akinobu Mita8d438282012-07-30 14:43:02 -07001427 specified notifier chain callbacks. It is useful to test the error
1428 handling of notifier call chain failures.
1429
1430 Say N if unsure.
1431
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001432config CPU_NOTIFIER_ERROR_INJECT
1433 tristate "CPU notifier error injection module"
Akinobu Mitaf5a9f522012-07-30 14:43:03 -07001434 depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001435 help
1436 This option provides a kernel module that can be used to test
Masanari Iidae41e85c2012-11-30 16:44:39 +09001437 the error handling of the cpu notifiers by injecting artificial
Akinobu Mitaf5a9f522012-07-30 14:43:03 -07001438 errors to CPU notifier chain callbacks. It is controlled through
1439 debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu
1440
1441 If the notifier call chain should be failed with some events
1442 notified, write the error code to "actions/<notifier event>/error".
1443
1444 Example: Inject CPU offline error (-1 == -EPERM)
1445
1446 # cd /sys/kernel/debug/notifier-error-inject/cpu
1447 # echo -1 > actions/CPU_DOWN_PREPARE/error
1448 # echo 0 > /sys/devices/system/cpu/cpu1/online
1449 bash: echo: write error: Operation not permitted
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001450
1451 To compile this code as a module, choose M here: the module will
1452 be called cpu-notifier-error-inject.
1453
1454 If unsure, say N.
1455
Akinobu Mita048b9c32012-07-30 14:43:07 -07001456config PM_NOTIFIER_ERROR_INJECT
1457 tristate "PM notifier error injection module"
1458 depends on PM && NOTIFIER_ERROR_INJECTION
1459 default m if PM_DEBUG
1460 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001461 This option provides the ability to inject artificial errors to
Akinobu Mita048b9c32012-07-30 14:43:07 -07001462 PM notifier chain callbacks. It is controlled through debugfs
1463 interface /sys/kernel/debug/notifier-error-inject/pm
1464
1465 If the notifier call chain should be failed with some events
1466 notified, write the error code to "actions/<notifier event>/error".
1467
1468 Example: Inject PM suspend error (-12 = -ENOMEM)
1469
1470 # cd /sys/kernel/debug/notifier-error-inject/pm/
1471 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1472 # echo mem > /sys/power/state
1473 bash: echo: write error: Cannot allocate memory
1474
1475 To compile this code as a module, choose M here: the module will
1476 be called pm-notifier-error-inject.
1477
1478 If unsure, say N.
1479
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001480config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1481 tristate "OF reconfig notifier error injection module"
1482 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001483 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001484 This option provides the ability to inject artificial errors to
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001485 OF reconfig notifier chain callbacks. It is controlled
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001486 through debugfs interface under
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001487 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001488
1489 If the notifier call chain should be failed with some events
1490 notified, write the error code to "actions/<notifier event>/error".
1491
1492 To compile this code as a module, choose M here: the module will
Akinobu Mitae12a95f2013-04-30 15:28:49 -07001493 be called of-reconfig-notifier-error-inject.
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001494
1495 If unsure, say N.
1496
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001497config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001498 bool "Fault-injection framework"
1499 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001500 help
1501 Provide fault-injection framework.
1502 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001503
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001504config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001505 bool "Fault-injection capability for kmalloc"
1506 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001507 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001508 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001509 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001510
Akinobu Mita933e3122006-12-08 02:39:45 -08001511config FAIL_PAGE_ALLOC
1512 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001513 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001514 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001515 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001516
Akinobu Mitac17bb492006-12-08 02:39:46 -08001517config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001518 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001519 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001520 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001521 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001522
Jens Axboe581d4e22008-09-14 05:56:33 -07001523config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d014392010-07-21 16:05:53 +09001524 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001525 depends on FAULT_INJECTION && BLOCK
1526 help
1527 Provide fault-injection capability on end IO handling. This
1528 will make the block layer "forget" an interrupt as configured,
1529 thus exercising the error handling.
1530
1531 Only works with drivers that use the generic timeout handling,
1532 for others it wont do anything.
1533
Per Forlin1b676f72011-08-19 14:52:37 +02001534config FAIL_MMC_REQUEST
1535 bool "Fault-injection capability for MMC IO"
1536 select DEBUG_FS
1537 depends on FAULT_INJECTION && MMC
1538 help
1539 Provide fault-injection capability for MMC IO.
1540 This will make the mmc core return data errors. This is
1541 useful to test the error handling in the mmc block device
1542 and to test how the mmc host driver handles retries from
1543 the block device.
1544
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001545config FAULT_INJECTION_DEBUG_FS
1546 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001547 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001548 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001549 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -08001550
1551config FAULT_INJECTION_STACKTRACE_FILTER
1552 bool "stacktrace filter for fault-injection capabilities"
1553 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001554 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001555 select STACKTRACE
Chen Gangdf2e1ef2014-06-23 13:22:04 -07001556 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !SCORE
Akinobu Mita1df49002007-02-20 13:57:56 -08001557 help
1558 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001559
Arjan van de Ven97455122008-01-25 21:08:34 +01001560config LATENCYTOP
1561 bool "Latency measuring infrastructure"
Randy Dunlap625fdca2010-08-12 12:31:21 -07001562 depends on HAVE_LATENCYTOP_SUPPORT
1563 depends on DEBUG_KERNEL
1564 depends on STACKTRACE_SUPPORT
1565 depends on PROC_FS
Vineet Guptacc80ae32013-08-27 13:52:51 +05301566 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC
Arjan van de Ven97455122008-01-25 21:08:34 +01001567 select KALLSYMS
1568 select KALLSYMS_ALL
1569 select STACKTRACE
1570 select SCHEDSTATS
1571 select SCHED_DEBUG
Arjan van de Ven97455122008-01-25 21:08:34 +01001572 help
1573 Enable this option if you want to use the LatencyTOP tool
1574 to find out which userspace is blocking on what kernel operations.
1575
Stephen Boyd446f24d2013-04-30 15:28:42 -07001576config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1577 bool
1578
1579config DEBUG_STRICT_USER_COPY_CHECKS
1580 bool "Strict user copy size checks"
1581 depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1582 depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING
1583 help
1584 Enabling this option turns a certain set of sanity checks for user
1585 copy operations into compile time failures.
1586
1587 The copy_from_user() etc checks are there to help test if there
1588 are sufficient security checks on the length argument of
1589 the copy operation, by having gcc prove that the argument is
1590 within bounds.
1591
1592 If unsure, say N.
1593
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001594source kernel/trace/Kconfig
1595
Dave Hansen881c5142013-07-01 13:04:44 -07001596menu "Runtime Testing"
1597
1598config LKDTM
1599 tristate "Linux Kernel Dump Test Tool Module"
1600 depends on DEBUG_FS
1601 depends on BLOCK
1602 default n
1603 help
1604 This module enables testing of the different dumping mechanisms by
1605 inducing system failures at predefined crash points.
1606 If you don't need it: say N
1607 Choose M here to compile this code as a module. The module will be
1608 called lkdtm.
1609
1610 Documentation on how to use the module can be found in
1611 Documentation/fault-injection/provoke-crashes.txt
1612
1613config TEST_LIST_SORT
1614 bool "Linked list sorting test"
1615 depends on DEBUG_KERNEL
1616 help
1617 Enable this to turn on 'list_sort()' function test. This test is
1618 executed only once during system boot, so affects only boot time.
1619
1620 If unsure, say N.
1621
1622config KPROBES_SANITY_TEST
1623 bool "Kprobes sanity tests"
1624 depends on DEBUG_KERNEL
1625 depends on KPROBES
1626 default n
1627 help
1628 This option provides for testing basic kprobes functionality on
1629 boot. A sample kprobe, jprobe and kretprobe are inserted and
1630 verified for functionality.
1631
1632 Say N if you are unsure.
1633
1634config BACKTRACE_SELF_TEST
1635 tristate "Self test for the backtrace code"
1636 depends on DEBUG_KERNEL
1637 default n
1638 help
1639 This option provides a kernel module that can be used to test
1640 the kernel stack backtrace code. This option is not useful
1641 for distributions or general kernels, but only for kernel
1642 developers working on architecture code.
1643
1644 Note that if you want to also test saved backtraces, you will
1645 have to enable STACKTRACE as well.
1646
1647 Say N if you are unsure.
1648
Michel Lespinasse910a7422012-10-08 16:30:39 -07001649config RBTREE_TEST
1650 tristate "Red-Black tree test"
Cody P Schafer7c993e12013-09-11 14:25:19 -07001651 depends on DEBUG_KERNEL
Michel Lespinasse910a7422012-10-08 16:30:39 -07001652 help
1653 A benchmark measuring the performance of the rbtree library.
1654 Also includes rbtree invariant checks.
1655
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001656config INTERVAL_TREE_TEST
1657 tristate "Interval tree test"
1658 depends on m && DEBUG_KERNEL
Chris Wilsona88cc102014-03-17 12:21:54 +00001659 select INTERVAL_TREE
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001660 help
1661 A benchmark measuring the performance of the interval tree library
1662
Greg Thelen623fd802013-11-12 15:08:34 -08001663config PERCPU_TEST
1664 tristate "Per cpu operations test"
1665 depends on m && DEBUG_KERNEL
1666 help
1667 Enable this option to build test module which validates per-cpu
1668 operations.
1669
1670 If unsure, say N.
1671
Dave Hansen881c5142013-07-01 13:04:44 -07001672config ATOMIC64_SELFTEST
1673 bool "Perform an atomic64_t self-test at boot"
1674 help
1675 Enable this option to test the atomic64_t functions at boot.
1676
1677 If unsure, say N.
1678
1679config ASYNC_RAID6_TEST
1680 tristate "Self test for hardware accelerated raid6 recovery"
1681 depends on ASYNC_RAID6_RECOV
1682 select ASYNC_MEMCPY
1683 ---help---
1684 This is a one-shot self test that permutes through the
1685 recovery of all the possible two disk failure scenarios for a
1686 N-disk array. Recovery is performed with the asynchronous
1687 raid6 recovery routines, and will optionally use an offload
1688 engine if one is available.
1689
1690 If unsure, say N.
1691
Andy Shevchenko64d1d772015-02-12 15:02:21 -08001692config TEST_HEXDUMP
1693 tristate "Test functions located in the hexdump module at runtime"
1694
Dave Hansen881c5142013-07-01 13:04:44 -07001695config TEST_STRING_HELPERS
1696 tristate "Test functions located in the string_helpers module at runtime"
1697
1698config TEST_KSTRTOX
1699 tristate "Test kstrto*() family of functions at runtime"
1700
Thomas Graf7e1e7762014-08-02 11:47:44 +02001701config TEST_RHASHTABLE
Geert Uytterhoeven9d6dbe12015-01-29 15:40:25 +01001702 tristate "Perform selftest on resizable hash table"
Thomas Graf7e1e7762014-08-02 11:47:44 +02001703 default n
1704 help
1705 Enable this option to test the rhashtable functions at boot.
1706
1707 If unsure, say N.
1708
Dave Hansen881c5142013-07-01 13:04:44 -07001709endmenu # runtime tests
1710
Bernhard Kaindlf212ec42008-01-30 13:34:11 +01001711config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +01001712 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +01001713 depends on PCI && X86
1714 help
1715 If you want to debug problems which hang or crash the kernel early
1716 on boot and the crashing machine has a FireWire port, you can use
1717 this feature to remotely access the memory of the crashed machine
1718 over FireWire. This employs remote DMA as part of the OHCI1394
1719 specification which is now the standard for FireWire controllers.
1720
1721 With remote DMA, you can monitor the printk buffer remotely using
1722 firescope and access all memory below 4GB using fireproxy from gdb.
1723 Even controlling a kernel debugger is possible using remote DMA.
1724
1725 Usage:
1726
1727 If ohci1394_dma=early is used as boot parameter, it will initialize
1728 all OHCI1394 controllers which are found in the PCI config space.
1729
1730 As all changes to the FireWire bus such as enabling and disabling
1731 devices cause a bus reset and thereby disable remote DMA for all
1732 devices, be sure to have the cable plugged and FireWire enabled on
1733 the debugging host before booting the debug target for debugging.
1734
1735 This code (~1k) is freed after boot. By then, the firewire stack
1736 in charge of the OHCI-1394 controllers should be used instead.
1737
1738 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +01001739
Randy Dunlap152de302009-02-20 15:38:47 -08001740config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -07001741 bool "Build targets in Documentation/ tree"
1742 depends on HEADERS_CHECK
1743 help
1744 This option attempts to build objects from the source files in the
1745 kernel Documentation/ tree.
1746
1747 Say N if you are unsure.
1748
Joerg Roedel5ee00bd2009-01-09 12:14:24 +01001749config DMA_API_DEBUG
1750 bool "Enable debugging of DMA-API usage"
1751 depends on HAVE_DMA_API_DEBUG
1752 help
1753 Enable this option to debug the use of the DMA API by device drivers.
1754 With this option you will be able to detect common bugs in device
1755 drivers like double-freeing of DMA mappings or freeing mappings that
1756 were never allocated.
Dan Williams0abdd7a2014-01-21 15:48:12 -08001757
1758 This also attempts to catch cases where a page owned by DMA is
1759 accessed by the cpu in a way that could cause data corruption. For
1760 example, this enables cow_user_page() to check that the source page is
1761 not undergoing DMA.
1762
1763 This option causes a performance degradation. Use only if you want to
1764 debug device drivers and dma interactions.
1765
1766 If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -04001767
Valentin Rothberg8a6f0b42014-10-13 15:51:38 -07001768config TEST_LKM
Kees Cook93e9ef82014-01-23 15:54:37 -08001769 tristate "Test module loading with 'hello world' module"
1770 default n
1771 depends on m
1772 help
1773 This builds the "test_module" module that emits "Hello, world"
1774 on printk when loaded. It is designed to be used for basic
1775 evaluation of the module loading subsystem (for example when
1776 validating module verification). It lacks any extra dependencies,
1777 and will not normally be loaded by the system unless explicitly
1778 requested by name.
1779
1780 If unsure, say N.
1781
Kees Cook3e2a4c12014-01-23 15:54:38 -08001782config TEST_USER_COPY
1783 tristate "Test user/kernel boundary protections"
1784 default n
1785 depends on m
1786 help
1787 This builds the "test_user_copy" module that runs sanity checks
1788 on the copy_to/from_user infrastructure, making sure basic
1789 user/kernel boundary testing is working. If it fails to load,
1790 a regression has been detected in the user/kernel memory boundary
1791 protections.
1792
1793 If unsure, say N.
1794
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001795config TEST_BPF
1796 tristate "Test BPF filter functionality"
1797 default n
Randy Dunlap98920ba2014-05-13 09:58:44 -07001798 depends on m && NET
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001799 help
1800 This builds the "test_bpf" module that runs various test vectors
1801 against the BPF interpreter or BPF JIT compiler depending on the
1802 current setting. This is in particular useful for BPF JIT compiler
1803 development, but also to run regression tests against changes in
Alexei Starovoitov3c731eb2014-09-26 00:17:07 -07001804 the interpreter code. It also enables test stubs for eBPF maps and
1805 verifier used by user space verifier testsuite.
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001806
1807 If unsure, say N.
1808
Kees Cook0a8adf52014-07-14 14:38:12 -07001809config TEST_FIRMWARE
1810 tristate "Test firmware loading via userspace interface"
1811 default n
1812 depends on FW_LOADER
1813 help
1814 This builds the "test_firmware" module that creates a userspace
1815 interface for testing firmware loading. This can be used to
1816 control the triggering of firmware loading without needing an
1817 actual firmware-using device. The contents can be rechecked by
1818 userspace.
1819
1820 If unsure, say N.
1821
David Rileye704f932014-06-16 14:58:32 -07001822config TEST_UDELAY
1823 tristate "udelay test driver"
1824 default n
1825 help
1826 This builds the "udelay_test" module that helps to make sure
1827 that udelay() is working properly.
1828
1829 If unsure, say N.
1830
Vladimir Murzin4a207992015-04-14 15:48:27 -07001831config MEMTEST
1832 bool "Memtest"
1833 depends on HAVE_MEMBLOCK
1834 ---help---
1835 This option adds a kernel parameter 'memtest', which allows memtest
1836 to be set.
1837 memtest=0, mean disabled; -- default
1838 memtest=1, mean do 1 test pattern;
1839 ...
Vladimir Murzin8d8cfb42015-04-14 15:48:40 -07001840 memtest=17, mean do 17 test patterns.
Vladimir Murzin4a207992015-04-14 15:48:27 -07001841 If you are unsure how to answer this question, answer N.
1842
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001843source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02001844
1845source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001846