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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
Jeff Garzikde488442007-10-25 04:06:13 -0400170config ENABLE_WARN_DEPRECATED
171 bool "Enable __deprecated logic"
172 default y
173 help
174 Enable the __deprecated logic in the kernel build.
175 Disable this to suppress the "warning: 'foo' is deprecated
176 (declared at kernel/power/somefile.c:1234)" messages.
177
Andrew Mortoncebc04b2006-08-14 22:43:18 -0700178config ENABLE_MUST_CHECK
179 bool "Enable __must_check logic"
180 default y
181 help
182 Enable the __must_check logic in the kernel build. Disable this to
183 suppress the "warning: ignoring return value of 'foo', declared with
184 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185
Andi Kleen35bb5b12008-02-22 15:15:03 +0100186config FRAME_WARN
187 int "Warn for stack frames larger than (needs gcc 4.4)"
188 range 0 8192
189 default 1024 if !64BIT
190 default 2048 if 64BIT
191 help
192 Tell gcc to warn at build time for stack frames larger than this.
193 Setting this too low will cause a lot of warnings.
194 Setting it to 0 disables the warning.
195 Requires gcc 4.4
196
Randy Dunlap99657c72009-09-18 12:49:22 -0700197config STRIP_ASM_SYMS
198 bool "Strip assembler-generated symbols during link"
199 default n
200 help
201 Strip internal assembler-generated symbols during a link (symbols
202 that look like '.Lxxx') so they don't pollute the output of
203 get_wchan() and suchlike.
204
Andi Kleen1873e872012-03-28 11:51:18 -0700205config READABLE_ASM
206 bool "Generate readable assembler code"
207 depends on DEBUG_KERNEL
208 help
209 Disable some compiler optimizations that tend to generate human unreadable
210 assembler output. This may make the kernel slightly slower, but it helps
211 to keep kernel developers who have to stare a lot at assembler listings
212 sane.
213
Arjan van de Venf71d20e2006-06-28 04:26:45 -0700214config UNUSED_SYMBOLS
215 bool "Enable unused/obsolete exported symbols"
216 default y if X86
217 help
218 Unused but exported symbols make the kernel needlessly bigger. For
219 that reason most of these unused exports will soon be removed. This
220 option is provided temporarily to provide a transition period in case
221 some external kernel module needs one of these symbols anyway. If you
222 encounter such a case in your module, consider if you are actually
223 using the right API. (rationale: since nobody in the kernel is using
224 this in a module, there is a pretty good chance it's actually the
225 wrong interface to use). If you really need the symbol, please send a
226 mail to the linux kernel mailing list mentioning the symbol and why
227 you really need it, and what the merge plan to the mainline kernel for
228 your module is.
229
Don Mullisbf4735a2006-12-10 02:18:37 -0800230config DEBUG_FS
231 bool "Debug Filesystem"
Don Mullisbf4735a2006-12-10 02:18:37 -0800232 help
233 debugfs is a virtual file system that kernel developers use to put
234 debugging files into. Enable this option to be able to read and
235 write to these files.
236
Robert P. J. Dayff543332008-05-20 00:06:00 +0200237 For detailed documentation on the debugfs API, see
238 Documentation/DocBook/filesystems.
239
Don Mullisbf4735a2006-12-10 02:18:37 -0800240 If unsure, say N.
241
242config HEADERS_CHECK
243 bool "Run 'make headers_check' when building vmlinux"
244 depends on !UML
245 help
246 This option will extract the user-visible kernel headers whenever
247 building the kernel, and will run basic sanity checks on them to
248 ensure that exported files do not attempt to include files which
249 were not exported, etc.
250
251 If you're making modifications to header files which are
252 relevant for userspace, say 'Y', and check the headers
253 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
254 your build tree), to make sure they're suitable.
255
Sam Ravnborg91341d42008-01-21 21:31:44 +0100256config DEBUG_SECTION_MISMATCH
257 bool "Enable full Section mismatch analysis"
Sam Ravnborg91341d42008-01-21 21:31:44 +0100258 help
259 The section mismatch analysis checks if there are illegal
260 references from one section to another section.
Michael Wittene809ab02011-04-17 04:08:48 +0000261 During linktime or runtime, some sections are dropped;
262 any use of code/data previously in these sections would
Sam Ravnborg91341d42008-01-21 21:31:44 +0100263 most likely result in an oops.
Michael Wittene809ab02011-04-17 04:08:48 +0000264 In the code, functions and variables are annotated with
Paul Gortmaker0db06282013-06-19 14:53:51 -0400265 __init,, etc. (see the full list in include/linux/init.h),
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100266 which results in the code/data being placed in specific sections.
Michael Wittene809ab02011-04-17 04:08:48 +0000267 The section mismatch analysis is always performed after a full
268 kernel build, and enabling this option causes the following
269 additional steps to occur:
270 - Add the option -fno-inline-functions-called-once to gcc commands.
271 When inlining a function annotated with __init in a non-init
272 function, we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100273 the analysis would not catch the illegal reference.
Michael Wittene809ab02011-04-17 04:08:48 +0000274 This option tells gcc to inline less (but it does result in
275 a larger kernel).
276 - Run the section mismatch analysis for each module/built-in.o file.
277 When we run the section mismatch analysis on vmlinux.o, we
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100278 lose valueble information about where the mismatch was
Sam Ravnborg91341d42008-01-21 21:31:44 +0100279 introduced.
280 Running the analysis for each module/built-in.o file
Michael Wittene809ab02011-04-17 04:08:48 +0000281 tells where the mismatch happens much closer to the
282 source. The drawback is that the same mismatch is
283 reported at least twice.
284 - Enable verbose reporting from modpost in order to help resolve
285 the section mismatches that are reported.
Sam Ravnborg91341d42008-01-21 21:31:44 +0100286
Dave Hansen6dfc0662013-07-01 13:04:46 -0700287#
288# Select this config option from the architecture Kconfig, if it
289# is preferred to always offer frame pointers as a config
290# option on the architecture (regardless of KERNEL_DEBUG):
291#
292config ARCH_WANT_FRAME_POINTERS
293 bool
294 help
295
296config FRAME_POINTER
297 bool "Compile the kernel with frame pointers"
298 depends on DEBUG_KERNEL && \
299 (CRIS || M68K || FRV || UML || \
300 AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \
301 ARCH_WANT_FRAME_POINTERS
302 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
303 help
304 If you say Y here the resulting kernel image will be slightly
305 larger and slower, but it gives very useful debugging information
306 in case of kernel bugs. (precise oopses/stacktraces/warnings)
307
308config DEBUG_FORCE_WEAK_PER_CPU
309 bool "Force weak per-cpu definitions"
310 depends on DEBUG_KERNEL
311 help
312 s390 and alpha require percpu variables in modules to be
313 defined weak to work around addressing range issue which
314 puts the following two restrictions on percpu variable
315 definitions.
316
317 1. percpu symbols must be unique whether static or not
318 2. percpu variables can't be defined inside a function
319
320 To ensure that generic code follows the above rules, this
321 option forces all percpu variables to be defined as weak.
322
323endmenu # "Compiler options"
324
325config MAGIC_SYSRQ
326 bool "Magic SysRq key"
327 depends on !UML
328 help
329 If you say Y here, you will have some control over the system even
330 if the system crashes for example during kernel debugging (e.g., you
331 will be able to flush the buffer cache to disk, reboot the system
332 immediately or dump some status information). This is accomplished
333 by pressing various keys while holding SysRq (Alt+PrintScreen). It
334 also works on a serial console (on PC hardware at least), if you
335 send a BREAK and then within 5 seconds a command keypress. The
336 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
337 unless you really know what this hack does.
338
Ben Hutchings8eaede42013-10-07 01:05:46 +0100339config MAGIC_SYSRQ_DEFAULT_ENABLE
340 hex "Enable magic SysRq key functions by default"
341 depends on MAGIC_SYSRQ
342 default 0x1
343 help
344 Specifies which SysRq key functions are enabled by default.
345 This may be set to 1 or 0 to enable or disable them all, or
346 to a bitmask as described in Documentation/sysrq.txt.
347
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800348config DEBUG_KERNEL
349 bool "Kernel debugging"
350 help
351 Say Y here if you are developing drivers or trying to debug and
352 identify kernel problems.
353
Dave Hansen0610c8a2013-07-01 13:04:43 -0700354menu "Memory Debugging"
David Woodhousea304e1b2007-02-12 00:52:00 -0800355
Dave Hansen0610c8a2013-07-01 13:04:43 -0700356source mm/Kconfig.debug
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800357
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700358config DEBUG_OBJECTS
359 bool "Debug object operations"
360 depends on DEBUG_KERNEL
361 help
362 If you say Y here, additional code will be inserted into the
363 kernel to track the life time of various objects and validate
364 the operations on those objects.
365
366config DEBUG_OBJECTS_SELFTEST
367 bool "Debug objects selftest"
368 depends on DEBUG_OBJECTS
369 help
370 This enables the selftest of the object debug code.
371
372config DEBUG_OBJECTS_FREE
373 bool "Debug objects in freed memory"
374 depends on DEBUG_OBJECTS
375 help
376 This enables checks whether a k/v free operation frees an area
377 which contains an object which has not been deactivated
378 properly. This can make kmalloc/kfree-intensive workloads
379 much slower.
380
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700381config DEBUG_OBJECTS_TIMERS
382 bool "Debug timer objects"
383 depends on DEBUG_OBJECTS
384 help
385 If you say Y here, additional code will be inserted into the
386 timer routines to track the life time of timer objects and
387 validate the timer operations.
388
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900389config DEBUG_OBJECTS_WORK
390 bool "Debug work objects"
391 depends on DEBUG_OBJECTS
392 help
393 If you say Y here, additional code will be inserted into the
394 work queue routines to track the life time of work objects and
395 validate the work operations.
396
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400397config DEBUG_OBJECTS_RCU_HEAD
398 bool "Debug RCU callbacks objects"
Mathieu Desnoyersfc2ecf72011-02-23 09:42:14 -0800399 depends on DEBUG_OBJECTS
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400400 help
401 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
402
Tejun Heoe2852ae2010-10-26 14:23:05 -0700403config DEBUG_OBJECTS_PERCPU_COUNTER
404 bool "Debug percpu counter objects"
405 depends on DEBUG_OBJECTS
406 help
407 If you say Y here, additional code will be inserted into the
408 percpu counter routines to track the life time of percpu counter
409 objects and validate the percpu counter operations.
410
Ingo Molnar3ae70202008-11-26 10:02:00 +0100411config DEBUG_OBJECTS_ENABLE_DEFAULT
412 int "debug_objects bootup default value (0-1)"
413 range 0 1
414 default "1"
415 depends on DEBUG_OBJECTS
416 help
417 Debug objects boot parameter default value
418
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800420 bool "Debug slab memory allocations"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200421 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 help
423 Say Y here to have the kernel do limited verification on memory
424 allocation as well as poisoning memory on free to catch use of freed
425 memory. This can make kmalloc/kfree-intensive workloads much slower.
426
Al Viro871751e2006-03-25 03:06:39 -0800427config DEBUG_SLAB_LEAK
428 bool "Memory leak debugging"
429 depends on DEBUG_SLAB
430
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700431config SLUB_DEBUG_ON
432 bool "SLUB debugging on by default"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200433 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700434 default n
435 help
436 Boot with debugging on by default. SLUB boots by default with
437 the runtime debug capabilities switched off. Enabling this is
438 equivalent to specifying the "slub_debug" parameter on boot.
439 There is no support for more fine grained debug control like
440 possible with slub_debug=xxx. SLUB debugging may be switched
441 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
442 "slub_debug=-".
443
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800444config SLUB_STATS
445 default n
446 bool "Enable SLUB performance statistics"
Christoph Lameterab4d5ed2010-10-05 13:57:26 -0500447 depends on SLUB && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800448 help
449 SLUB statistics are useful to debug SLUBs allocation behavior in
450 order find ways to optimize the allocator. This should never be
451 enabled for production use since keeping statistics slows down
452 the allocator by a few percentage points. The slabinfo command
453 supports the determination of the most active slabs to figure
454 out which slabs are relevant to a particular load.
455 Try running: slabinfo -DA
456
Catalin Marinasb69ec422012-10-08 16:28:11 -0700457config HAVE_DEBUG_KMEMLEAK
458 bool
459
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100460config DEBUG_KMEMLEAK
461 bool "Kernel memory leak detector"
Kees Cook525c1f92013-01-16 18:54:16 -0800462 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
Catalin Marinas79e0d9b2011-04-27 17:06:19 +0100463 select DEBUG_FS
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100464 select STACKTRACE if STACKTRACE_SUPPORT
465 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800466 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100467 help
468 Say Y here if you want to enable the memory leak
469 detector. The memory allocation/freeing is traced in a way
470 similar to the Boehm's conservative garbage collector, the
471 difference being that the orphan objects are not freed but
472 only shown in /sys/kernel/debug/kmemleak. Enabling this
473 feature will introduce an overhead to memory
474 allocations. See Documentation/kmemleak.txt for more
475 details.
476
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100477 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
478 of finding leaks due to the slab objects poisoning.
479
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100480 In order to access the kmemleak file, debugfs needs to be
481 mounted (usually at /sys/kernel/debug).
482
Catalin Marinasa9d90582009-06-25 10:16:11 +0100483config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
484 int "Maximum kmemleak early log entries"
485 depends on DEBUG_KMEMLEAK
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200486 range 200 40000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100487 default 400
488 help
489 Kmemleak must track all the memory allocations to avoid
490 reporting false positives. Since memory may be allocated or
491 freed before kmemleak is initialised, an early log buffer is
492 used to store these actions. If kmemleak reports "early log
493 buffer exceeded", please increase this value.
494
Catalin Marinas0822ee42009-06-11 13:24:14 +0100495config DEBUG_KMEMLEAK_TEST
496 tristate "Simple test for the kernel memory leak detector"
Daniel Baluta97182692011-04-04 15:06:44 -0700497 depends on DEBUG_KMEMLEAK && m
Catalin Marinas0822ee42009-06-11 13:24:14 +0100498 help
Daniel Baluta97182692011-04-04 15:06:44 -0700499 This option enables a module that explicitly leaks memory.
Catalin Marinas0822ee42009-06-11 13:24:14 +0100500
501 If unsure, say N.
502
Jason Baronab0155a2010-07-19 11:54:17 +0100503config DEBUG_KMEMLEAK_DEFAULT_OFF
504 bool "Default kmemleak to off"
505 depends on DEBUG_KMEMLEAK
506 help
507 Say Y here to disable kmemleak by default. It can then be enabled
508 on the command line via kmemleak=on.
509
Dave Hansen0610c8a2013-07-01 13:04:43 -0700510config DEBUG_STACK_USAGE
511 bool "Stack utilization instrumentation"
512 depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG
513 help
514 Enables the display of the minimum amount of free stack which each
515 task has ever had available in the sysrq-T and sysrq-P debug output.
516
517 This option will slow down process creation somewhat.
518
519config DEBUG_VM
520 bool "Debug VM"
521 depends on DEBUG_KERNEL
522 help
523 Enable this to turn on extended checks in the virtual-memory system
524 that may impact performance.
525
526 If unsure, say N.
527
Davidlohr Bueso4f115142014-06-04 16:06:46 -0700528config DEBUG_VM_VMACACHE
529 bool "Debug VMA caching"
530 depends on DEBUG_VM
531 help
532 Enable this to turn on VMA caching debug information. Doing so
533 can cause significant overhead, so only enable it in non-production
534 environments.
535
536 If unsure, say N.
537
Dave Hansen0610c8a2013-07-01 13:04:43 -0700538config DEBUG_VM_RB
539 bool "Debug VM red-black trees"
540 depends on DEBUG_VM
541 help
Davidlohr Buesoa663dad2014-04-18 15:07:22 -0700542 Enable VM red-black tree debugging information and extra validations.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700543
544 If unsure, say N.
545
546config DEBUG_VIRTUAL
547 bool "Debug VM translations"
548 depends on DEBUG_KERNEL && X86
549 help
550 Enable some costly sanity checks in virtual to page code. This can
551 catch mistakes with virt_to_page() and friends.
552
553 If unsure, say N.
554
555config DEBUG_NOMMU_REGIONS
556 bool "Debug the global anon/private NOMMU mapping region tree"
557 depends on DEBUG_KERNEL && !MMU
558 help
559 This option causes the global tree of anonymous and private mapping
560 regions to be regularly checked for invalid topology.
561
562config DEBUG_MEMORY_INIT
563 bool "Debug memory initialisation" if EXPERT
564 default !EXPERT
565 help
566 Enable this for additional checks during memory initialisation.
567 The sanity checks verify aspects of the VM such as the memory model
568 and other information provided by the architecture. Verbose
569 information will be printed at KERN_DEBUG loglevel depending
570 on the mminit_loglevel= command-line option.
571
572 If unsure, say Y
573
574config MEMORY_NOTIFIER_ERROR_INJECT
575 tristate "Memory hotplug notifier error injection module"
576 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
577 help
578 This option provides the ability to inject artificial errors to
579 memory hotplug notifier chain callbacks. It is controlled through
580 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
581
582 If the notifier call chain should be failed with some events
583 notified, write the error code to "actions/<notifier event>/error".
584
585 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
586
587 # cd /sys/kernel/debug/notifier-error-inject/memory
588 # echo -12 > actions/MEM_GOING_OFFLINE/error
589 # echo offline > /sys/devices/system/memory/memoryXXX/state
590 bash: echo: write error: Cannot allocate memory
591
592 To compile this code as a module, choose M here: the module will
593 be called memory-notifier-error-inject.
594
595 If unsure, say N.
596
597config DEBUG_PER_CPU_MAPS
598 bool "Debug access to per_cpu maps"
599 depends on DEBUG_KERNEL
600 depends on SMP
601 help
602 Say Y to verify that the per_cpu map being accessed has
603 been set up. This adds a fair amount of code to kernel memory
604 and decreases performance.
605
606 Say N if unsure.
607
608config DEBUG_HIGHMEM
609 bool "Highmem debugging"
610 depends on DEBUG_KERNEL && HIGHMEM
611 help
Geert Uytterhoevenb1357c92014-04-14 18:55:50 +0200612 This option enables additional error checking for high memory
613 systems. Disable for production systems.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700614
615config HAVE_DEBUG_STACKOVERFLOW
616 bool
617
618config DEBUG_STACKOVERFLOW
619 bool "Check for stack overflows"
620 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
621 ---help---
622 Say Y here if you want to check for overflows of kernel, IRQ
623 and exception stacks (if your archicture uses them). This
624 option will show detailed messages if free stack space drops
625 below a certain limit.
626
627 These kinds of bugs usually occur when call-chains in the
628 kernel get too deep, especially when interrupts are
629 involved.
630
631 Use this in cases where you see apparently random memory
632 corruption, especially if it appears in 'struct thread_info'
633
634 If in doubt, say "N".
635
636source "lib/Kconfig.kmemcheck"
637
638endmenu # "Memory Debugging"
639
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640config DEBUG_SHIRQ
641 bool "Debug shared IRQ handlers"
Martin Schwidefsky0244ad02013-08-30 09:39:53 +0200642 depends on DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 help
644 Enable this to generate a spurious interrupt as soon as a shared
645 interrupt handler is registered, and just before one is deregistered.
646 Drivers ought to be able to handle interrupts coming in at those
647 points; some don't and need to be caught.
648
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700649menu "Debug Lockups and Hangs"
650
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651config LOCKUP_DETECTOR
652 bool "Detect Hard and Soft Lockups"
653 depends on DEBUG_KERNEL && !S390
654 help
655 Say Y here to enable the kernel to act as a watchdog to detect
656 hard and soft lockups.
657
658 Softlockups are bugs that cause the kernel to loop in kernel
659 mode for more than 20 seconds, without giving other tasks a
660 chance to run. The current stack trace is displayed upon
661 detection and the system will stay locked up.
662
663 Hardlockups are bugs that cause the CPU to loop in kernel mode
664 for more than 10 seconds, without letting other interrupts have a
665 chance to run. The current stack trace is displayed upon detection
666 and the system will stay locked up.
667
668 The overhead should be minimal. A periodic hrtimer runs to
669 generate interrupts and kick the watchdog task every 4 seconds.
670 An NMI is generated every 10 seconds or so to check for hardlockups.
671
672 The frequency of hrtimer and NMI events and the soft and hard lockup
673 thresholds can be controlled through the sysctl watchdog_thresh.
674
675config HARDLOCKUP_DETECTOR
676 def_bool y
677 depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG
678 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
679
680config BOOTPARAM_HARDLOCKUP_PANIC
681 bool "Panic (Reboot) On Hard Lockups"
682 depends on HARDLOCKUP_DETECTOR
683 help
684 Say Y here to enable the kernel to panic on "hard lockups",
685 which are bugs that cause the kernel to loop in kernel
686 mode with interrupts disabled for more than 10 seconds (configurable
687 using the watchdog_thresh sysctl).
688
689 Say N if unsure.
690
691config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
692 int
693 depends on HARDLOCKUP_DETECTOR
694 range 0 1
695 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
696 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
697
698config BOOTPARAM_SOFTLOCKUP_PANIC
699 bool "Panic (Reboot) On Soft Lockups"
700 depends on LOCKUP_DETECTOR
701 help
702 Say Y here to enable the kernel to panic on "soft lockups",
703 which are bugs that cause the kernel to loop in kernel
704 mode for more than 20 seconds (configurable using the watchdog_thresh
705 sysctl), without giving other tasks a chance to run.
706
707 The panic can be used in combination with panic_timeout,
708 to cause the system to reboot automatically after a
709 lockup has been detected. This feature is useful for
710 high-availability systems that have uptime guarantees and
711 where a lockup must be resolved ASAP.
712
Ingo Molnar8637c092006-07-03 00:24:38 -0700713 Say N if unsure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714
715config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
716 int
717 depends on LOCKUP_DETECTOR
718 range 0 1
719 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
720 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700721
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722config DETECT_HUNG_TASK
723 bool "Detect Hung Tasks"
724 depends on DEBUG_KERNEL
725 default LOCKUP_DETECTOR
726 help
727 Say Y here to enable the kernel to detect "hung tasks",
728 which are bugs that cause the task to be stuck in
729 uninterruptible "D" state indefinitiley.
730
731 When a hung task is detected, the kernel will print the
732 current stack trace (which you should report), but the
733 task will stay in uninterruptible state. If lockdep is
734 enabled then all held locks will also be reported. This
735 feature has negligible overhead.
736
737config DEFAULT_HUNG_TASK_TIMEOUT
738 int "Default timeout for hung task detection (in seconds)"
739 depends on DETECT_HUNG_TASK
740 default 120
741 help
742 This option controls the default timeout (in seconds) used
743 to determine when a task has become non-responsive and should
744 be considered hung.
745
746 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
747 sysctl or by writing a value to
748 /proc/sys/kernel/hung_task_timeout_secs.
749
Ingo Molnar408894e2006-01-09 15:59:20 -0800750 A timeout of 0 disables the check. The default is two minutes.
751 Keeping the default should be fine in most cases.
752
753config BOOTPARAM_HUNG_TASK_PANIC
754 bool "Panic (Reboot) On Hung Tasks"
755 depends on DETECT_HUNG_TASK
Tim Chencca57c52006-04-18 22:21:47 -0700756 help
Ingo Molnar408894e2006-01-09 15:59:20 -0800757 Say Y here to enable the kernel to panic on "hung tasks",
758 which are bugs that cause the kernel to leave a task stuck
759 in uninterruptible "D" state.
760
761 The panic can be used in combination with panic_timeout,
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700762 to cause the system to reboot automatically after a
763 hung task has been detected. This feature is useful for
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700764 high-availability systems that have uptime guarantees and
765 where a hung tasks must be resolved ASAP.
766
767 Say N if unsure.
768
769config BOOTPARAM_HUNG_TASK_PANIC_VALUE
770 int
771 depends on DETECT_HUNG_TASK
772 range 0 1
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100773 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 default 1 if BOOTPARAM_HUNG_TASK_PANIC
775
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700776endmenu # "Debug lockups and hangs"
777
778config PANIC_ON_OOPS
779 bool "Panic on Oops"
780 help
781 Say Y here to enable the kernel to panic when it oopses. This
782 has the same effect as setting oops=panic on the kernel command
783 line.
784
785 This feature is useful to ensure that the kernel does not do
786 anything erroneous after an oops which could result in data
787 corruption or other issues.
788
789 Say N if unsure.
790
791config PANIC_ON_OOPS_VALUE
792 int
793 range 0 1
794 default 0 if !PANIC_ON_OOPS
795 default 1 if PANIC_ON_OOPS
796
Jason Baron5800dc32013-11-25 23:23:04 +0000797config PANIC_TIMEOUT
798 int "panic timeout"
799 default 0
800 help
801 Set the timeout value (in seconds) until a reboot occurs when the
802 the kernel panics. If n = 0, then we wait forever. A timeout
803 value n > 0 will wait n seconds before rebooting, while a timeout
804 value n < 0 will reboot immediately.
805
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806config SCHED_DEBUG
807 bool "Collect scheduler debugging info"
808 depends on DEBUG_KERNEL && PROC_FS
809 default y
810 help
811 If you say Y here, the /proc/sched_debug file will be provided
812 that can help debug the scheduler. The runtime overhead of this
813 option is minimal.
814
815config SCHEDSTATS
816 bool "Collect scheduler statistics"
817 depends on DEBUG_KERNEL && PROC_FS
818 help
819 If you say Y here, additional code will be inserted into the
820 scheduler and related routines to collect statistics about
821 scheduler behavior and provide them in /proc/schedstat. These
822 stats may be useful for both tuning and debugging the scheduler
823 If you aren't debugging the scheduler or trying to tune a specific
824 application, you can say N to avoid the very slight overhead
825 this adds.
826
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700827config TIMER_STATS
828 bool "Collect kernel timers statistics"
829 depends on DEBUG_KERNEL && PROC_FS
830 help
831 If you say Y here, additional code will be inserted into the
832 timer routines to collect statistics about kernel timers being
833 reprogrammed. The statistics can be read from /proc/timer_stats.
834 The statistics collection is started by writing 1 to /proc/timer_stats,
835 writing 0 stops it. This feature is useful to collect information
836 about timer usage patterns in kernel and userspace. This feature
837 is lightweight if enabled in the kernel config but not activated
838 (it defaults to deactivated on bootup and will only be activated
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700839 if some application like powertop activates it explicitly).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841config DEBUG_PREEMPT
842 bool "Debug preemptible kernel"
Kumar Gala01deab92009-10-16 07:21:39 +0000843 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 default y
845 help
846 If you say Y here then the kernel will use a debug variant of the
847 commonly used smp_processor_id() function and will print warnings
848 if kernel code uses it in a preemption-unsafe way. Also, the kernel
849 will detect preemption count underflows.
850
Dave Hansen9eade162013-07-01 13:04:47 -0700851menu "Lock Debugging (spinlocks, mutexes, etc...)"
852
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853config DEBUG_RT_MUTEXES
854 bool "RT Mutex debugging, deadlock detection"
855 depends on DEBUG_KERNEL && RT_MUTEXES
856 help
857 This allows rt mutex semantics violations and rt mutex related
858 deadlocks (lockups) to be detected and reported automatically.
859
Linus Torvalds1da177e2005-04-16 15:20:36 -0700860config RT_MUTEX_TESTER
861 bool "Built-in scriptable tester for rt-mutexes"
Thomas Gleixner6cc620b2014-06-22 00:03:21 +0200862 depends on DEBUG_KERNEL && RT_MUTEXES && BROKEN
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863 help
864 This option enables a rt-mutex tester.
865
866config DEBUG_SPINLOCK
867 bool "Spinlock and rw-lock debugging: basic checks"
868 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +0530869 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 help
871 Say Y here and build SMP to catch missing spinlock initialization
872 and certain other kinds of spinlock errors commonly made. This is
873 best used in conjunction with the NMI watchdog so that spinlock
874 deadlocks are also debuggable.
875
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700876config DEBUG_MUTEXES
877 bool "Mutex debugging: basic checks"
878 depends on DEBUG_KERNEL
879 help
880 This feature allows mutex semantics violations to be detected and
881 reported.
882
Daniel Vetter23010022013-06-20 13:31:17 +0200883config DEBUG_WW_MUTEX_SLOWPATH
884 bool "Wait/wound mutex debugging: Slowpath testing"
885 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
886 select DEBUG_LOCK_ALLOC
887 select DEBUG_SPINLOCK
888 select DEBUG_MUTEXES
889 help
890 This feature enables slowpath testing for w/w mutex users by
891 injecting additional -EDEADLK wound/backoff cases. Together with
892 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
893 will test all possible w/w mutex interface abuse with the
894 exception of simply not acquiring all the required locks.
Rob Clark4d692372014-08-27 11:19:26 -0400895 Note that this feature can introduce significant overhead, so
896 it really should not be enabled in a production or distro kernel,
897 even a debug kernel. If you are a driver writer, enable it. If
898 you are a distro, do not.
Daniel Vetter23010022013-06-20 13:31:17 +0200899
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700900config DEBUG_LOCK_ALLOC
901 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700902 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700903 select DEBUG_SPINLOCK
904 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700905 select LOCKDEP
906 help
907 This feature will check whether any held lock (spinlock, rwlock,
908 mutex or rwsem) is incorrectly freed by the kernel, via any of the
909 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
910 vfree(), etc.), whether a live lock is incorrectly reinitialized via
911 spin_lock_init()/mutex_init()/etc., or whether there is any lock
912 held during task exit.
913
914config PROVE_LOCKING
915 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700916 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700917 select LOCKDEP
918 select DEBUG_SPINLOCK
919 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700920 select DEBUG_LOCK_ALLOC
Steven Rostedt46b93b72010-08-31 16:35:20 -0400921 select TRACE_IRQFLAGS
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700922 default n
923 help
924 This feature enables the kernel to prove that all locking
925 that occurs in the kernel runtime is mathematically
926 correct: that under no circumstance could an arbitrary (and
927 not yet triggered) combination of observed locking
928 sequences (on an arbitrary number of CPUs, running an
929 arbitrary number of tasks and interrupt contexts) cause a
930 deadlock.
931
932 In short, this feature enables the kernel to report locking
933 related deadlocks before they actually occur.
934
935 The proof does not depend on how hard and complex a
936 deadlock scenario would be to trigger: how many
937 participant CPUs, tasks and irq-contexts would be needed
938 for it to trigger. The proof also does not depend on
939 timing: if a race and a resulting deadlock is possible
940 theoretically (no matter how unlikely the race scenario
941 is), it will be proven so and will immediately be
942 reported by the kernel (once the event is observed that
943 makes the deadlock theoretically possible).
944
945 If a deadlock is impossible (i.e. the locking rules, as
946 observed by the kernel, are mathematically correct), the
947 kernel reports nothing.
948
949 NOTE: this feature can also be enabled for rwlocks, mutexes
950 and rwsems - in which case all dependencies between these
951 different locking variants are observed and mapped too, and
952 the proof of observed correctness is also maintained for an
953 arbitrary combination of these separate locking variants.
954
955 For more details, see Documentation/lockdep-design.txt.
956
957config LOCKDEP
958 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700959 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700960 select STACKTRACE
Chen Gangdf2e1ef2014-06-23 13:22:04 -0700961 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC && !SCORE
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700962 select KALLSYMS
963 select KALLSYMS_ALL
964
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700965config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700966 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700967 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
968 select LOCKDEP
969 select DEBUG_SPINLOCK
970 select DEBUG_MUTEXES
971 select DEBUG_LOCK_ALLOC
972 default n
973 help
974 This feature enables tracking lock contention points
975
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700976 For more details, see Documentation/lockstat.txt
977
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +0100978 This also enables lock events required by "perf lock",
979 subcommand of perf.
980 If you want to use "perf lock", you also need to turn on
981 CONFIG_EVENT_TRACING.
Hitoshi Mitake84c6f882010-02-04 16:08:15 +0900982
983 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +0100984 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
Hitoshi Mitake84c6f882010-02-04 16:08:15 +0900985
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700986config DEBUG_LOCKDEP
987 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700988 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700989 help
990 If you say Y here, the lock dependency engine will do
991 additional runtime checks to debug itself, at the price
992 of more runtime overhead.
993
Frederic Weisbeckerd902db12011-06-08 19:31:56 +0200994config DEBUG_ATOMIC_SLEEP
995 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +0200996 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997 depends on DEBUG_KERNEL
998 help
999 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001000 noisy if they are called inside atomic sections: when a spinlock is
1001 held, inside an rcu read side critical section, inside preempt disabled
1002 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003
Ingo Molnarcae2ed92006-07-03 00:24:48 -07001004config DEBUG_LOCKING_API_SELFTESTS
1005 bool "Locking API boot-time self-tests"
1006 depends on DEBUG_KERNEL
1007 help
1008 Say Y here if you want the kernel to run a short self-test during
1009 bootup. The self-test checks whether common types of locking bugs
1010 are detected by debugging mechanisms or not. (if you disable
1011 lock debugging then those bugs wont be detected of course.)
1012 The following locking APIs are covered: spinlocks, rwlocks,
1013 mutexes and rwsems.
1014
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001015config LOCK_TORTURE_TEST
1016 tristate "torture tests for locking"
1017 depends on DEBUG_KERNEL
1018 select TORTURE_TEST
1019 default n
1020 help
1021 This option provides a kernel module that runs torture tests
1022 on kernel locking primitives. The kernel module may be built
1023 after the fact on the running kernel to be tested, if desired.
1024
1025 Say Y here if you want kernel locking-primitive torture tests
1026 to be built into the kernel.
1027 Say M if you want these torture tests to build as a module.
1028 Say N if you are unsure.
1029
Dave Hansen9eade162013-07-01 13:04:47 -07001030endmenu # lock debugging
1031
1032config TRACE_IRQFLAGS
1033 bool
1034 help
1035 Enables hooks to interrupt enabling and disabling for
1036 either tracing or lock debugging.
1037
Ingo Molnar8637c092006-07-03 00:24:38 -07001038config STACKTRACE
Dave Jones0c38e1f2014-08-29 15:18:35 -07001039 bool "Stack backtrace support"
Ingo Molnar8637c092006-07-03 00:24:38 -07001040 depends on STACKTRACE_SUPPORT
Dave Jones0c38e1f2014-08-29 15:18:35 -07001041 help
1042 This option causes the kernel to create a /proc/pid/stack for
1043 every process, showing its current stack trace.
1044 It is also used by various kernel debugging features that require
1045 stack trace generation.
Ingo Molnar8637c092006-07-03 00:24:38 -07001046
Linus Torvalds1da177e2005-04-16 15:20:36 -07001047config DEBUG_KOBJECT
1048 bool "kobject debugging"
1049 depends on DEBUG_KERNEL
1050 help
1051 If you say Y here, some extra kobject debugging messages will be sent
1052 to the syslog.
1053
Russell Kingc817a672013-06-27 15:06:14 +01001054config DEBUG_KOBJECT_RELEASE
1055 bool "kobject release debugging"
Linus Torvalds2a999aa2013-10-29 08:33:36 -07001056 depends on DEBUG_OBJECTS_TIMERS
Russell Kingc817a672013-06-27 15:06:14 +01001057 help
1058 kobjects are reference counted objects. This means that their
1059 last reference count put is not predictable, and the kobject can
1060 live on past the point at which a driver decides to drop it's
1061 initial reference to the kobject gained on allocation. An
1062 example of this would be a struct device which has just been
1063 unregistered.
1064
1065 However, some buggy drivers assume that after such an operation,
1066 the memory backing the kobject can be immediately freed. This
1067 goes completely against the principles of a refcounted object.
1068
1069 If you say Y here, the kernel will delay the release of kobjects
1070 on the last reference count to improve the visibility of this
1071 kind of kobject release bug.
1072
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001073config HAVE_DEBUG_BUGVERBOSE
1074 bool
1075
Linus Torvalds1da177e2005-04-16 15:20:36 -07001076config DEBUG_BUGVERBOSE
David Rientjes6a108a12011-01-20 14:44:16 -08001077 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001078 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
Alexey Dobriyan8420e7e2009-12-14 18:00:25 -08001079 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080 help
1081 Say Y here to make BUG() panics output the file name and line number
1082 of the BUG call as well as the EIP and oops trace. This aids
1083 debugging but costs about 70-100K of memory.
1084
Dave Jones199a9af2006-09-29 01:59:00 -07001085config DEBUG_LIST
1086 bool "Debug linked list manipulation"
1087 depends on DEBUG_KERNEL
1088 help
1089 Enable this to turn on extended checks in the linked-list
1090 walking routines.
1091
1092 If unsure, say N.
1093
Dan Streetmanb8cfff62014-06-04 16:11:54 -07001094config DEBUG_PI_LIST
1095 bool "Debug priority linked list manipulation"
1096 depends on DEBUG_KERNEL
1097 help
1098 Enable this to turn on extended checks in the priority-ordered
1099 linked-list (plist) walking routines. This checks the entire
1100 list multiple times during each manipulation.
1101
1102 If unsure, say N.
1103
Jens Axboed6ec0842007-10-22 20:01:06 +02001104config DEBUG_SG
1105 bool "Debug SG table operations"
1106 depends on DEBUG_KERNEL
1107 help
1108 Enable this to turn on checks on scatter-gather tables. This can
1109 help find problems with drivers that do not properly initialize
1110 their sg tables.
1111
1112 If unsure, say N.
1113
Arjan van de Ven1b2439d2008-08-15 15:29:38 -07001114config DEBUG_NOTIFIERS
1115 bool "Debug notifier call chains"
1116 depends on DEBUG_KERNEL
1117 help
1118 Enable this to turn on sanity checking for notifier call chains.
1119 This is most useful for kernel developers to make sure that
1120 modules properly unregister themselves from notifier chains.
1121 This is a relatively cheap check but if you care about maximum
1122 performance, say N.
1123
David Howellse0e81732009-09-02 09:13:40 +01001124config DEBUG_CREDENTIALS
1125 bool "Debug credential management"
1126 depends on DEBUG_KERNEL
1127 help
1128 Enable this to turn on some debug checking for credential
1129 management. The additional code keeps track of the number of
1130 pointers from task_structs to any given cred struct, and checks to
1131 see that this number never exceeds the usage count of the cred
1132 struct.
1133
1134 Furthermore, if SELinux is enabled, this also checks that the
1135 security pointer in the cred struct is never seen to be invalid.
1136
1137 If unsure, say N.
1138
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001139menu "RCU Debugging"
1140
1141config PROVE_RCU
1142 bool "RCU debugging: prove RCU correctness"
1143 depends on PROVE_LOCKING
1144 default n
1145 help
1146 This feature enables lockdep extensions that check for correct
1147 use of RCU APIs. This is currently under development. Say Y
1148 if you want to debug RCU usage or help work on the PROVE_RCU
1149 feature.
1150
1151 Say N if you are unsure.
1152
1153config PROVE_RCU_REPEATEDLY
1154 bool "RCU debugging: don't disable PROVE_RCU on first splat"
1155 depends on PROVE_RCU
1156 default n
1157 help
1158 By itself, PROVE_RCU will disable checking upon issuing the
1159 first warning (or "splat"). This feature prevents such
1160 disabling, allowing multiple RCU-lockdep warnings to be printed
1161 on a single reboot.
1162
1163 Say Y to allow multiple RCU-lockdep warnings per boot.
1164
1165 Say N if you are unsure.
1166
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001167config SPARSE_RCU_POINTER
1168 bool "RCU debugging: sparse-based checks for pointer usage"
1169 default n
1170 help
1171 This feature enables the __rcu sparse annotation for
1172 RCU-protected pointers. This annotation will cause sparse
1173 to flag any non-RCU used of annotated pointers. This can be
1174 helpful when debugging RCU usage. Please note that this feature
1175 is not intended to enforce code cleanliness; it is instead merely
1176 a debugging aid.
1177
1178 Say Y to make sparse flag questionable use of RCU-protected pointers
1179
1180 Say N if you are unsure.
1181
Paul E. McKenney51b11302014-01-27 11:49:39 -08001182config TORTURE_TEST
1183 tristate
1184 default n
1185
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001186config RCU_TORTURE_TEST
1187 tristate "torture tests for RCU"
1188 depends on DEBUG_KERNEL
Paul E. McKenney51b11302014-01-27 11:49:39 -08001189 select TORTURE_TEST
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001190 default n
1191 help
1192 This option provides a kernel module that runs torture tests
1193 on the RCU infrastructure. The kernel module may be built
1194 after the fact on the running kernel to be tested, if desired.
1195
Paul E. McKenney31a72bc2008-06-18 09:26:49 -07001196 Say Y here if you want RCU torture tests to be built into
1197 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001198 Say M if you want the RCU torture tests to build as a module.
1199 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -07001200
Paul E. McKenney31a72bc2008-06-18 09:26:49 -07001201config RCU_TORTURE_TEST_RUNNABLE
1202 bool "torture tests for RCU runnable by default"
1203 depends on RCU_TORTURE_TEST = y
1204 default n
1205 help
1206 This option provides a way to build the RCU torture tests
1207 directly into the kernel without them starting up at boot
1208 time. You can use /proc/sys/kernel/rcutorture_runnable
1209 to manually override this setting. This /proc file is
1210 available only when the RCU torture tests have been built
1211 into the kernel.
1212
1213 Say Y here if you want the RCU torture tests to start during
1214 boot (you probably don't).
1215 Say N here if you want the RCU torture tests to start only
1216 after being manually enabled via /proc.
1217
Paul E. McKenneyb1637602010-06-02 16:21:38 -07001218config RCU_CPU_STALL_TIMEOUT
1219 int "RCU CPU stall timeout in seconds"
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -07001220 depends on RCU_STALL_COMMON
Paul E. McKenneyb1637602010-06-02 16:21:38 -07001221 range 3 300
Paul E. McKenneyc8960542012-10-25 17:59:23 -07001222 default 21
Paul E. McKenneyb1637602010-06-02 16:21:38 -07001223 help
1224 If a given RCU grace period extends more than the specified
1225 number of seconds, a CPU stall warning is printed. If the
1226 RCU grace period persists, additional CPU stall warnings are
1227 printed at more widely spaced intervals.
1228
Paul E. McKenney1ed509a2010-02-22 17:05:05 -08001229config RCU_CPU_STALL_VERBOSE
1230 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
Paul E. McKenneya00e0d712011-02-08 17:14:39 -08001231 depends on TREE_PREEMPT_RCU
Paul E. McKenney55ec9362010-04-13 12:22:33 -07001232 default y
Paul E. McKenney1ed509a2010-02-22 17:05:05 -08001233 help
1234 This option causes RCU to printk detailed per-task information
1235 for any tasks that are stalling the current RCU grace period.
Paul E. McKenney64db4cf2008-12-18 21:55:32 +01001236
1237 Say N if you are unsure.
1238
Paul E. McKenney1ed509a2010-02-22 17:05:05 -08001239 Say Y if you want to enable such checks.
1240
Paul E. McKenneya858af22012-01-16 13:29:10 -08001241config RCU_CPU_STALL_INFO
1242 bool "Print additional diagnostics on RCU CPU stall"
1243 depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
1244 default n
1245 help
1246 For each stalled CPU that is aware of the current RCU grace
1247 period, print out additional per-CPU diagnostic information
1248 regarding scheduling-clock ticks, idle state, and,
1249 for RCU_FAST_NO_HZ kernels, idle-entry state.
1250
1251 Say N if you are unsure.
1252
1253 Say Y if you want to enable such diagnostics.
1254
Paul E. McKenney5c8806a2012-01-06 15:10:44 -08001255config RCU_TRACE
1256 bool "Enable tracing for RCU"
1257 depends on DEBUG_KERNEL
Paul E. McKenney52494532012-11-14 16:26:40 -08001258 select TRACE_CLOCK
Paul E. McKenney5c8806a2012-01-06 15:10:44 -08001259 help
1260 This option provides tracing in RCU which presents stats
1261 in debugfs for debugging RCU implementation.
1262
1263 Say Y here if you want to enable RCU tracing
1264 Say N if you are unsure.
1265
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001266endmenu # "RCU Debugging"
1267
Tejun Heo870d6652008-08-25 19:47:25 +09001268config DEBUG_BLOCK_EXT_DEVT
1269 bool "Force extended block device numbers and spread them"
1270 depends on DEBUG_KERNEL
1271 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +02001272 default n
Tejun Heo870d6652008-08-25 19:47:25 +09001273 help
Tejun Heo0e11e342008-10-13 10:46:01 +02001274 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1275 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1276 YOU ARE DOING. Distros, please enable this and fix whatever
1277 is broken.
1278
Tejun Heo870d6652008-08-25 19:47:25 +09001279 Conventionally, block device numbers are allocated from
1280 predetermined contiguous area. However, extended block area
1281 may introduce non-contiguous block device numbers. This
1282 option forces most block device numbers to be allocated from
1283 the extended space and spreads them to discover kernel or
1284 userland code paths which assume predetermined contiguous
1285 device number allocation.
1286
Tejun Heo55dc7db2008-09-01 13:44:35 +02001287 Note that turning on this debug option shuffles all the
1288 device numbers for all IDE and SCSI devices including libata
1289 ones, so root partition specified using device number
1290 directly (via rdev or root=MAJ:MIN) won't work anymore.
1291 Textual device names (root=/dev/sdXn) will continue to work.
1292
Tejun Heo870d6652008-08-25 19:47:25 +09001293 Say N if you are unsure.
1294
Akinobu Mita8d438282012-07-30 14:43:02 -07001295config NOTIFIER_ERROR_INJECTION
1296 tristate "Notifier error injection"
1297 depends on DEBUG_KERNEL
1298 select DEBUG_FS
1299 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001300 This option provides the ability to inject artificial errors to
Akinobu Mita8d438282012-07-30 14:43:02 -07001301 specified notifier chain callbacks. It is useful to test the error
1302 handling of notifier call chain failures.
1303
1304 Say N if unsure.
1305
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001306config CPU_NOTIFIER_ERROR_INJECT
1307 tristate "CPU notifier error injection module"
Akinobu Mitaf5a9f522012-07-30 14:43:03 -07001308 depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001309 help
1310 This option provides a kernel module that can be used to test
Masanari Iidae41e85c2012-11-30 16:44:39 +09001311 the error handling of the cpu notifiers by injecting artificial
Akinobu Mitaf5a9f522012-07-30 14:43:03 -07001312 errors to CPU notifier chain callbacks. It is controlled through
1313 debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu
1314
1315 If the notifier call chain should be failed with some events
1316 notified, write the error code to "actions/<notifier event>/error".
1317
1318 Example: Inject CPU offline error (-1 == -EPERM)
1319
1320 # cd /sys/kernel/debug/notifier-error-inject/cpu
1321 # echo -1 > actions/CPU_DOWN_PREPARE/error
1322 # echo 0 > /sys/devices/system/cpu/cpu1/online
1323 bash: echo: write error: Operation not permitted
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001324
1325 To compile this code as a module, choose M here: the module will
1326 be called cpu-notifier-error-inject.
1327
1328 If unsure, say N.
1329
Akinobu Mita048b9c32012-07-30 14:43:07 -07001330config PM_NOTIFIER_ERROR_INJECT
1331 tristate "PM notifier error injection module"
1332 depends on PM && NOTIFIER_ERROR_INJECTION
1333 default m if PM_DEBUG
1334 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001335 This option provides the ability to inject artificial errors to
Akinobu Mita048b9c32012-07-30 14:43:07 -07001336 PM notifier chain callbacks. It is controlled through debugfs
1337 interface /sys/kernel/debug/notifier-error-inject/pm
1338
1339 If the notifier call chain should be failed with some events
1340 notified, write the error code to "actions/<notifier event>/error".
1341
1342 Example: Inject PM suspend error (-12 = -ENOMEM)
1343
1344 # cd /sys/kernel/debug/notifier-error-inject/pm/
1345 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1346 # echo mem > /sys/power/state
1347 bash: echo: write error: Cannot allocate memory
1348
1349 To compile this code as a module, choose M here: the module will
1350 be called pm-notifier-error-inject.
1351
1352 If unsure, say N.
1353
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001354config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1355 tristate "OF reconfig notifier error injection module"
1356 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001357 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001358 This option provides the ability to inject artificial errors to
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001359 OF reconfig notifier chain callbacks. It is controlled
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001360 through debugfs interface under
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001361 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001362
1363 If the notifier call chain should be failed with some events
1364 notified, write the error code to "actions/<notifier event>/error".
1365
1366 To compile this code as a module, choose M here: the module will
Akinobu Mitae12a95f2013-04-30 15:28:49 -07001367 be called of-reconfig-notifier-error-inject.
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001368
1369 If unsure, say N.
1370
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001371config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001372 bool "Fault-injection framework"
1373 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001374 help
1375 Provide fault-injection framework.
1376 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001377
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001378config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001379 bool "Fault-injection capability for kmalloc"
1380 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001381 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001382 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001383 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001384
Akinobu Mita933e3122006-12-08 02:39:45 -08001385config FAIL_PAGE_ALLOC
1386 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001387 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001388 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001389 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001390
Akinobu Mitac17bb492006-12-08 02:39:46 -08001391config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001392 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001393 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001394 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001395 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001396
Jens Axboe581d4e22008-09-14 05:56:33 -07001397config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d014392010-07-21 16:05:53 +09001398 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001399 depends on FAULT_INJECTION && BLOCK
1400 help
1401 Provide fault-injection capability on end IO handling. This
1402 will make the block layer "forget" an interrupt as configured,
1403 thus exercising the error handling.
1404
1405 Only works with drivers that use the generic timeout handling,
1406 for others it wont do anything.
1407
Per Forlin1b676f72011-08-19 14:52:37 +02001408config FAIL_MMC_REQUEST
1409 bool "Fault-injection capability for MMC IO"
1410 select DEBUG_FS
1411 depends on FAULT_INJECTION && MMC
1412 help
1413 Provide fault-injection capability for MMC IO.
1414 This will make the mmc core return data errors. This is
1415 useful to test the error handling in the mmc block device
1416 and to test how the mmc host driver handles retries from
1417 the block device.
1418
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001419config FAULT_INJECTION_DEBUG_FS
1420 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001421 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001422 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001423 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -08001424
1425config FAULT_INJECTION_STACKTRACE_FILTER
1426 bool "stacktrace filter for fault-injection capabilities"
1427 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001428 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001429 select STACKTRACE
Chen Gangdf2e1ef2014-06-23 13:22:04 -07001430 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !SCORE
Akinobu Mita1df49002007-02-20 13:57:56 -08001431 help
1432 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001433
Arjan van de Ven97455122008-01-25 21:08:34 +01001434config LATENCYTOP
1435 bool "Latency measuring infrastructure"
Randy Dunlap625fdca2010-08-12 12:31:21 -07001436 depends on HAVE_LATENCYTOP_SUPPORT
1437 depends on DEBUG_KERNEL
1438 depends on STACKTRACE_SUPPORT
1439 depends on PROC_FS
Vineet Guptacc80ae32013-08-27 13:52:51 +05301440 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC
Arjan van de Ven97455122008-01-25 21:08:34 +01001441 select KALLSYMS
1442 select KALLSYMS_ALL
1443 select STACKTRACE
1444 select SCHEDSTATS
1445 select SCHED_DEBUG
Arjan van de Ven97455122008-01-25 21:08:34 +01001446 help
1447 Enable this option if you want to use the LatencyTOP tool
1448 to find out which userspace is blocking on what kernel operations.
1449
Stephen Boyd446f24d2013-04-30 15:28:42 -07001450config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1451 bool
1452
1453config DEBUG_STRICT_USER_COPY_CHECKS
1454 bool "Strict user copy size checks"
1455 depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1456 depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING
1457 help
1458 Enabling this option turns a certain set of sanity checks for user
1459 copy operations into compile time failures.
1460
1461 The copy_from_user() etc checks are there to help test if there
1462 are sufficient security checks on the length argument of
1463 the copy operation, by having gcc prove that the argument is
1464 within bounds.
1465
1466 If unsure, say N.
1467
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001468source kernel/trace/Kconfig
1469
Dave Hansen881c5142013-07-01 13:04:44 -07001470menu "Runtime Testing"
1471
1472config LKDTM
1473 tristate "Linux Kernel Dump Test Tool Module"
1474 depends on DEBUG_FS
1475 depends on BLOCK
1476 default n
1477 help
1478 This module enables testing of the different dumping mechanisms by
1479 inducing system failures at predefined crash points.
1480 If you don't need it: say N
1481 Choose M here to compile this code as a module. The module will be
1482 called lkdtm.
1483
1484 Documentation on how to use the module can be found in
1485 Documentation/fault-injection/provoke-crashes.txt
1486
1487config TEST_LIST_SORT
1488 bool "Linked list sorting test"
1489 depends on DEBUG_KERNEL
1490 help
1491 Enable this to turn on 'list_sort()' function test. This test is
1492 executed only once during system boot, so affects only boot time.
1493
1494 If unsure, say N.
1495
1496config KPROBES_SANITY_TEST
1497 bool "Kprobes sanity tests"
1498 depends on DEBUG_KERNEL
1499 depends on KPROBES
1500 default n
1501 help
1502 This option provides for testing basic kprobes functionality on
1503 boot. A sample kprobe, jprobe and kretprobe are inserted and
1504 verified for functionality.
1505
1506 Say N if you are unsure.
1507
1508config BACKTRACE_SELF_TEST
1509 tristate "Self test for the backtrace code"
1510 depends on DEBUG_KERNEL
1511 default n
1512 help
1513 This option provides a kernel module that can be used to test
1514 the kernel stack backtrace code. This option is not useful
1515 for distributions or general kernels, but only for kernel
1516 developers working on architecture code.
1517
1518 Note that if you want to also test saved backtraces, you will
1519 have to enable STACKTRACE as well.
1520
1521 Say N if you are unsure.
1522
Michel Lespinasse910a7422012-10-08 16:30:39 -07001523config RBTREE_TEST
1524 tristate "Red-Black tree test"
Cody P Schafer7c993e12013-09-11 14:25:19 -07001525 depends on DEBUG_KERNEL
Michel Lespinasse910a7422012-10-08 16:30:39 -07001526 help
1527 A benchmark measuring the performance of the rbtree library.
1528 Also includes rbtree invariant checks.
1529
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001530config INTERVAL_TREE_TEST
1531 tristate "Interval tree test"
1532 depends on m && DEBUG_KERNEL
Chris Wilsona88cc102014-03-17 12:21:54 +00001533 select INTERVAL_TREE
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001534 help
1535 A benchmark measuring the performance of the interval tree library
1536
Greg Thelen623fd802013-11-12 15:08:34 -08001537config PERCPU_TEST
1538 tristate "Per cpu operations test"
1539 depends on m && DEBUG_KERNEL
1540 help
1541 Enable this option to build test module which validates per-cpu
1542 operations.
1543
1544 If unsure, say N.
1545
Dave Hansen881c5142013-07-01 13:04:44 -07001546config ATOMIC64_SELFTEST
1547 bool "Perform an atomic64_t self-test at boot"
1548 help
1549 Enable this option to test the atomic64_t functions at boot.
1550
1551 If unsure, say N.
1552
1553config ASYNC_RAID6_TEST
1554 tristate "Self test for hardware accelerated raid6 recovery"
1555 depends on ASYNC_RAID6_RECOV
1556 select ASYNC_MEMCPY
1557 ---help---
1558 This is a one-shot self test that permutes through the
1559 recovery of all the possible two disk failure scenarios for a
1560 N-disk array. Recovery is performed with the asynchronous
1561 raid6 recovery routines, and will optionally use an offload
1562 engine if one is available.
1563
1564 If unsure, say N.
1565
1566config TEST_STRING_HELPERS
1567 tristate "Test functions located in the string_helpers module at runtime"
1568
1569config TEST_KSTRTOX
1570 tristate "Test kstrto*() family of functions at runtime"
1571
Thomas Graf7e1e7762014-08-02 11:47:44 +02001572config TEST_RHASHTABLE
1573 bool "Perform selftest on resizable hash table"
1574 default n
1575 help
1576 Enable this option to test the rhashtable functions at boot.
1577
1578 If unsure, say N.
1579
Dave Hansen881c5142013-07-01 13:04:44 -07001580endmenu # runtime tests
1581
Bernhard Kaindlf212ec42008-01-30 13:34:11 +01001582config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +01001583 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +01001584 depends on PCI && X86
1585 help
1586 If you want to debug problems which hang or crash the kernel early
1587 on boot and the crashing machine has a FireWire port, you can use
1588 this feature to remotely access the memory of the crashed machine
1589 over FireWire. This employs remote DMA as part of the OHCI1394
1590 specification which is now the standard for FireWire controllers.
1591
1592 With remote DMA, you can monitor the printk buffer remotely using
1593 firescope and access all memory below 4GB using fireproxy from gdb.
1594 Even controlling a kernel debugger is possible using remote DMA.
1595
1596 Usage:
1597
1598 If ohci1394_dma=early is used as boot parameter, it will initialize
1599 all OHCI1394 controllers which are found in the PCI config space.
1600
1601 As all changes to the FireWire bus such as enabling and disabling
1602 devices cause a bus reset and thereby disable remote DMA for all
1603 devices, be sure to have the cable plugged and FireWire enabled on
1604 the debugging host before booting the debug target for debugging.
1605
1606 This code (~1k) is freed after boot. By then, the firewire stack
1607 in charge of the OHCI-1394 controllers should be used instead.
1608
1609 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +01001610
Randy Dunlap152de302009-02-20 15:38:47 -08001611config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -07001612 bool "Build targets in Documentation/ tree"
1613 depends on HEADERS_CHECK
1614 help
1615 This option attempts to build objects from the source files in the
1616 kernel Documentation/ tree.
1617
1618 Say N if you are unsure.
1619
Joerg Roedel5ee00bd2009-01-09 12:14:24 +01001620config DMA_API_DEBUG
1621 bool "Enable debugging of DMA-API usage"
1622 depends on HAVE_DMA_API_DEBUG
1623 help
1624 Enable this option to debug the use of the DMA API by device drivers.
1625 With this option you will be able to detect common bugs in device
1626 drivers like double-freeing of DMA mappings or freeing mappings that
1627 were never allocated.
Dan Williams0abdd7a2014-01-21 15:48:12 -08001628
1629 This also attempts to catch cases where a page owned by DMA is
1630 accessed by the cpu in a way that could cause data corruption. For
1631 example, this enables cow_user_page() to check that the source page is
1632 not undergoing DMA.
1633
1634 This option causes a performance degradation. Use only if you want to
1635 debug device drivers and dma interactions.
1636
1637 If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -04001638
Kees Cook93e9ef82014-01-23 15:54:37 -08001639config TEST_MODULE
1640 tristate "Test module loading with 'hello world' module"
1641 default n
1642 depends on m
1643 help
1644 This builds the "test_module" module that emits "Hello, world"
1645 on printk when loaded. It is designed to be used for basic
1646 evaluation of the module loading subsystem (for example when
1647 validating module verification). It lacks any extra dependencies,
1648 and will not normally be loaded by the system unless explicitly
1649 requested by name.
1650
1651 If unsure, say N.
1652
Kees Cook3e2a4c12014-01-23 15:54:38 -08001653config TEST_USER_COPY
1654 tristate "Test user/kernel boundary protections"
1655 default n
1656 depends on m
1657 help
1658 This builds the "test_user_copy" module that runs sanity checks
1659 on the copy_to/from_user infrastructure, making sure basic
1660 user/kernel boundary testing is working. If it fails to load,
1661 a regression has been detected in the user/kernel memory boundary
1662 protections.
1663
1664 If unsure, say N.
1665
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001666config TEST_BPF
1667 tristate "Test BPF filter functionality"
1668 default n
Randy Dunlap98920ba2014-05-13 09:58:44 -07001669 depends on m && NET
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001670 help
1671 This builds the "test_bpf" module that runs various test vectors
1672 against the BPF interpreter or BPF JIT compiler depending on the
1673 current setting. This is in particular useful for BPF JIT compiler
1674 development, but also to run regression tests against changes in
1675 the interpreter code.
1676
1677 If unsure, say N.
1678
Kees Cook0a8adf52014-07-14 14:38:12 -07001679config TEST_FIRMWARE
1680 tristate "Test firmware loading via userspace interface"
1681 default n
1682 depends on FW_LOADER
1683 help
1684 This builds the "test_firmware" module that creates a userspace
1685 interface for testing firmware loading. This can be used to
1686 control the triggering of firmware loading without needing an
1687 actual firmware-using device. The contents can be rechecked by
1688 userspace.
1689
1690 If unsure, say N.
1691
David Rileye704f932014-06-16 14:58:32 -07001692config TEST_UDELAY
1693 tristate "udelay test driver"
1694 default n
1695 help
1696 This builds the "udelay_test" module that helps to make sure
1697 that udelay() is working properly.
1698
1699 If unsure, say N.
1700
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001701source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02001702
1703source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001704