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Linus Torvalds1da177e2005-04-16 15:20:36 -07001
2config PRINTK_TIME
3 bool "Show timing information on printks"
Randy Dunlapd3b8b6e2006-12-06 20:36:38 -08004 depends on PRINTK
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 help
Kay Sievers649e6ee2012-05-10 04:30:45 +02006 Selecting this option causes time stamps of the printk()
7 messages to be added to the output of the syslog() system
8 call and at the console.
9
10 The timestamp is always recorded internally, and exported
11 to /dev/kmsg. This flag just specifies if the timestamp should
12 be included, not that the timestamp is recorded.
13
14 The behavior is also controlled by the kernel command line
15 parameter printk.time=1. See Documentation/kernel-parameters.txt
Linus Torvalds1da177e2005-04-16 15:20:36 -070016
Mandeep Singh Baines5af5bcb2011-03-22 16:34:23 -070017config DEFAULT_MESSAGE_LOGLEVEL
18 int "Default message log level (1-7)"
19 range 1 7
20 default "4"
21 help
22 Default log level for printk statements with no specified priority.
23
24 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
25 that are auditing their logs closely may want to set it to a lower
26 priority.
27
Jeff Garzikde488442007-10-25 04:06:13 -040028config ENABLE_WARN_DEPRECATED
29 bool "Enable __deprecated logic"
30 default y
31 help
32 Enable the __deprecated logic in the kernel build.
33 Disable this to suppress the "warning: 'foo' is deprecated
34 (declared at kernel/power/somefile.c:1234)" messages.
35
Andrew Mortoncebc04b2006-08-14 22:43:18 -070036config ENABLE_MUST_CHECK
37 bool "Enable __must_check logic"
38 default y
39 help
40 Enable the __must_check logic in the kernel build. Disable this to
41 suppress the "warning: ignoring return value of 'foo', declared with
42 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -070043
Andi Kleen35bb5b12008-02-22 15:15:03 +010044config FRAME_WARN
45 int "Warn for stack frames larger than (needs gcc 4.4)"
46 range 0 8192
47 default 1024 if !64BIT
48 default 2048 if 64BIT
49 help
50 Tell gcc to warn at build time for stack frames larger than this.
51 Setting this too low will cause a lot of warnings.
52 Setting it to 0 disables the warning.
53 Requires gcc 4.4
54
Linus Torvalds1da177e2005-04-16 15:20:36 -070055config MAGIC_SYSRQ
56 bool "Magic SysRq key"
Adrian Bunkf346f4b2006-01-09 20:54:51 -080057 depends on !UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 help
59 If you say Y here, you will have some control over the system even
60 if the system crashes for example during kernel debugging (e.g., you
61 will be able to flush the buffer cache to disk, reboot the system
62 immediately or dump some status information). This is accomplished
63 by pressing various keys while holding SysRq (Alt+PrintScreen). It
64 also works on a serial console (on PC hardware at least), if you
65 send a BREAK and then within 5 seconds a command keypress. The
66 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
67 unless you really know what this hack does.
68
Randy Dunlap99657c72009-09-18 12:49:22 -070069config STRIP_ASM_SYMS
70 bool "Strip assembler-generated symbols during link"
71 default n
72 help
73 Strip internal assembler-generated symbols during a link (symbols
74 that look like '.Lxxx') so they don't pollute the output of
75 get_wchan() and suchlike.
76
Andi Kleen1873e872012-03-28 11:51:18 -070077config READABLE_ASM
78 bool "Generate readable assembler code"
79 depends on DEBUG_KERNEL
80 help
81 Disable some compiler optimizations that tend to generate human unreadable
82 assembler output. This may make the kernel slightly slower, but it helps
83 to keep kernel developers who have to stare a lot at assembler listings
84 sane.
85
Arjan van de Venf71d20e2006-06-28 04:26:45 -070086config UNUSED_SYMBOLS
87 bool "Enable unused/obsolete exported symbols"
88 default y if X86
89 help
90 Unused but exported symbols make the kernel needlessly bigger. For
91 that reason most of these unused exports will soon be removed. This
92 option is provided temporarily to provide a transition period in case
93 some external kernel module needs one of these symbols anyway. If you
94 encounter such a case in your module, consider if you are actually
95 using the right API. (rationale: since nobody in the kernel is using
96 this in a module, there is a pretty good chance it's actually the
97 wrong interface to use). If you really need the symbol, please send a
98 mail to the linux kernel mailing list mentioning the symbol and why
99 you really need it, and what the merge plan to the mainline kernel for
100 your module is.
101
Don Mullisbf4735a2006-12-10 02:18:37 -0800102config DEBUG_FS
103 bool "Debug Filesystem"
Don Mullisbf4735a2006-12-10 02:18:37 -0800104 help
105 debugfs is a virtual file system that kernel developers use to put
106 debugging files into. Enable this option to be able to read and
107 write to these files.
108
Robert P. J. Dayff543332008-05-20 00:06:00 +0200109 For detailed documentation on the debugfs API, see
110 Documentation/DocBook/filesystems.
111
Don Mullisbf4735a2006-12-10 02:18:37 -0800112 If unsure, say N.
113
114config HEADERS_CHECK
115 bool "Run 'make headers_check' when building vmlinux"
116 depends on !UML
117 help
118 This option will extract the user-visible kernel headers whenever
119 building the kernel, and will run basic sanity checks on them to
120 ensure that exported files do not attempt to include files which
121 were not exported, etc.
122
123 If you're making modifications to header files which are
124 relevant for userspace, say 'Y', and check the headers
125 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
126 your build tree), to make sure they're suitable.
127
Sam Ravnborg91341d42008-01-21 21:31:44 +0100128config DEBUG_SECTION_MISMATCH
129 bool "Enable full Section mismatch analysis"
Sam Ravnborg91341d42008-01-21 21:31:44 +0100130 help
131 The section mismatch analysis checks if there are illegal
132 references from one section to another section.
Michael Wittene809ab02011-04-17 04:08:48 +0000133 During linktime or runtime, some sections are dropped;
134 any use of code/data previously in these sections would
Sam Ravnborg91341d42008-01-21 21:31:44 +0100135 most likely result in an oops.
Michael Wittene809ab02011-04-17 04:08:48 +0000136 In the code, functions and variables are annotated with
137 __init, __devinit, etc. (see the full list in include/linux/init.h),
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100138 which results in the code/data being placed in specific sections.
Michael Wittene809ab02011-04-17 04:08:48 +0000139 The section mismatch analysis is always performed after a full
140 kernel build, and enabling this option causes the following
141 additional steps to occur:
142 - Add the option -fno-inline-functions-called-once to gcc commands.
143 When inlining a function annotated with __init in a non-init
144 function, we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100145 the analysis would not catch the illegal reference.
Michael Wittene809ab02011-04-17 04:08:48 +0000146 This option tells gcc to inline less (but it does result in
147 a larger kernel).
148 - Run the section mismatch analysis for each module/built-in.o file.
149 When we run the section mismatch analysis on vmlinux.o, we
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100150 lose valueble information about where the mismatch was
Sam Ravnborg91341d42008-01-21 21:31:44 +0100151 introduced.
152 Running the analysis for each module/built-in.o file
Michael Wittene809ab02011-04-17 04:08:48 +0000153 tells where the mismatch happens much closer to the
154 source. The drawback is that the same mismatch is
155 reported at least twice.
156 - Enable verbose reporting from modpost in order to help resolve
157 the section mismatches that are reported.
Sam Ravnborg91341d42008-01-21 21:31:44 +0100158
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800159config DEBUG_KERNEL
160 bool "Kernel debugging"
161 help
162 Say Y here if you are developing drivers or trying to debug and
163 identify kernel problems.
164
David Woodhousea304e1b2007-02-12 00:52:00 -0800165config DEBUG_SHIRQ
166 bool "Debug shared IRQ handlers"
167 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
168 help
169 Enable this to generate a spurious interrupt as soon as a shared
170 interrupt handler is registered, and just before one is deregistered.
171 Drivers ought to be able to handle interrupts coming in at those
172 points; some don't and need to be caught.
173
Don Zickus58687ac2010-05-07 17:11:44 -0400174config LOCKUP_DETECTOR
175 bool "Detect Hard and Soft Lockups"
Heiko Carstensdea20a32006-10-11 01:20:44 -0700176 depends on DEBUG_KERNEL && !S390
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700177 help
Don Zickus58687ac2010-05-07 17:11:44 -0400178 Say Y here to enable the kernel to act as a watchdog to detect
179 hard and soft lockups.
Don Zickus84e478c2010-02-05 21:47:05 -0500180
Don Zickus58687ac2010-05-07 17:11:44 -0400181 Softlockups are bugs that cause the kernel to loop in kernel
Fernando Luis Vázquez Cao5f329082012-02-09 17:42:21 -0500182 mode for more than 20 seconds, without giving other tasks a
Don Zickus58687ac2010-05-07 17:11:44 -0400183 chance to run. The current stack trace is displayed upon
184 detection and the system will stay locked up.
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700185
Don Zickus58687ac2010-05-07 17:11:44 -0400186 Hardlockups are bugs that cause the CPU to loop in kernel mode
Fernando Luis Vázquez Cao5f329082012-02-09 17:42:21 -0500187 for more than 10 seconds, without letting other interrupts have a
Don Zickus58687ac2010-05-07 17:11:44 -0400188 chance to run. The current stack trace is displayed upon detection
189 and the system will stay locked up.
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700190
Don Zickus58687ac2010-05-07 17:11:44 -0400191 The overhead should be minimal. A periodic hrtimer runs to
Fernando Luis Vázquez Cao5f329082012-02-09 17:42:21 -0500192 generate interrupts and kick the watchdog task every 4 seconds.
193 An NMI is generated every 10 seconds or so to check for hardlockups.
194
195 The frequency of hrtimer and NMI events and the soft and hard lockup
196 thresholds can be controlled through the sysctl watchdog_thresh.
Don Zickus84e478c2010-02-05 21:47:05 -0500197
Frederic Weisbecker23637d42010-05-15 23:15:20 +0200198config HARDLOCKUP_DETECTOR
Don Zickus4a7863c2010-12-22 14:00:03 -0500199 def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI && \
Cong Wangd314d742012-03-23 15:01:51 -0700200 !HAVE_NMI_WATCHDOG
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700201
Don Zickusfef2c9b2011-03-22 16:34:16 -0700202config BOOTPARAM_HARDLOCKUP_PANIC
203 bool "Panic (Reboot) On Hard Lockups"
204 depends on LOCKUP_DETECTOR
205 help
206 Say Y here to enable the kernel to panic on "hard lockups",
207 which are bugs that cause the kernel to loop in kernel
Fernando Luis Vázquez Cao5f329082012-02-09 17:42:21 -0500208 mode with interrupts disabled for more than 10 seconds (configurable
209 using the watchdog_thresh sysctl).
Don Zickusfef2c9b2011-03-22 16:34:16 -0700210
211 Say N if unsure.
212
213config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
214 int
215 depends on LOCKUP_DETECTOR
216 range 0 1
217 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
218 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
219
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200220config BOOTPARAM_SOFTLOCKUP_PANIC
221 bool "Panic (Reboot) On Soft Lockups"
Frederic Weisbecker89d7ce22010-05-13 00:27:20 +0200222 depends on LOCKUP_DETECTOR
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200223 help
224 Say Y here to enable the kernel to panic on "soft lockups",
225 which are bugs that cause the kernel to loop in kernel
Fernando Luis Vázquez Cao5f329082012-02-09 17:42:21 -0500226 mode for more than 20 seconds (configurable using the watchdog_thresh
227 sysctl), without giving other tasks a chance to run.
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200228
229 The panic can be used in combination with panic_timeout,
230 to cause the system to reboot automatically after a
231 lockup has been detected. This feature is useful for
232 high-availability systems that have uptime guarantees and
233 where a lockup must be resolved ASAP.
234
235 Say N if unsure.
236
237config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
238 int
Frederic Weisbeckere16bb1d2010-05-15 22:30:22 +0200239 depends on LOCKUP_DETECTOR
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200240 range 0 1
241 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
242 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
243
Kyle McMartin2a01bb32012-04-11 08:15:29 -0400244config PANIC_ON_OOPS
245 bool "Panic on Oops" if EXPERT
246 default n
247 help
248 Say Y here to enable the kernel to panic when it oopses. This
249 has the same effect as setting oops=panic on the kernel command
250 line.
251
252 This feature is useful to ensure that the kernel does not do
253 anything erroneous after an oops which could result in data
254 corruption or other issues.
255
256 Say N if unsure.
257
258config PANIC_ON_OOPS_VALUE
259 int
260 range 0 1
261 default 0 if !PANIC_ON_OOPS
262 default 1 if PANIC_ON_OOPS
263
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800264config DETECT_HUNG_TASK
265 bool "Detect Hung Tasks"
266 depends on DEBUG_KERNEL
Anton Blanchard8edbb832011-07-05 13:32:40 +1000267 default LOCKUP_DETECTOR
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800268 help
269 Say Y here to enable the kernel to detect "hung tasks",
270 which are bugs that cause the task to be stuck in
271 uninterruptible "D" state indefinitiley.
272
273 When a hung task is detected, the kernel will print the
274 current stack trace (which you should report), but the
275 task will stay in uninterruptible state. If lockdep is
276 enabled then all held locks will also be reported. This
277 feature has negligible overhead.
278
Jeff Mahoneye11feaa2011-04-27 14:27:24 -0400279config DEFAULT_HUNG_TASK_TIMEOUT
280 int "Default timeout for hung task detection (in seconds)"
281 depends on DETECT_HUNG_TASK
282 default 120
283 help
284 This option controls the default timeout (in seconds) used
285 to determine when a task has become non-responsive and should
286 be considered hung.
287
Jiaju Zhangc51eaac2011-10-31 17:10:07 -0700288 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
289 sysctl or by writing a value to
290 /proc/sys/kernel/hung_task_timeout_secs.
Jeff Mahoneye11feaa2011-04-27 14:27:24 -0400291
292 A timeout of 0 disables the check. The default is two minutes.
293 Keeping the default should be fine in most cases.
294
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800295config BOOTPARAM_HUNG_TASK_PANIC
296 bool "Panic (Reboot) On Hung Tasks"
297 depends on DETECT_HUNG_TASK
298 help
299 Say Y here to enable the kernel to panic on "hung tasks",
300 which are bugs that cause the kernel to leave a task stuck
301 in uninterruptible "D" state.
302
303 The panic can be used in combination with panic_timeout,
304 to cause the system to reboot automatically after a
305 hung task has been detected. This feature is useful for
306 high-availability systems that have uptime guarantees and
307 where a hung tasks must be resolved ASAP.
308
309 Say N if unsure.
310
311config BOOTPARAM_HUNG_TASK_PANIC_VALUE
312 int
313 depends on DETECT_HUNG_TASK
314 range 0 1
315 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
316 default 1 if BOOTPARAM_HUNG_TASK_PANIC
317
Ingo Molnarb642b6d2007-07-09 18:52:00 +0200318config SCHED_DEBUG
319 bool "Collect scheduler debugging info"
320 depends on DEBUG_KERNEL && PROC_FS
321 default y
322 help
323 If you say Y here, the /proc/sched_debug file will be provided
324 that can help debug the scheduler. The runtime overhead of this
325 option is minimal.
326
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327config SCHEDSTATS
328 bool "Collect scheduler statistics"
329 depends on DEBUG_KERNEL && PROC_FS
330 help
331 If you say Y here, additional code will be inserted into the
332 scheduler and related routines to collect statistics about
333 scheduler behavior and provide them in /proc/schedstat. These
334 stats may be useful for both tuning and debugging the scheduler
335 If you aren't debugging the scheduler or trying to tune a specific
336 application, you can say N to avoid the very slight overhead
337 this adds.
338
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800339config TIMER_STATS
340 bool "Collect kernel timers statistics"
341 depends on DEBUG_KERNEL && PROC_FS
342 help
343 If you say Y here, additional code will be inserted into the
344 timer routines to collect statistics about kernel timers being
345 reprogrammed. The statistics can be read from /proc/timer_stats.
346 The statistics collection is started by writing 1 to /proc/timer_stats,
347 writing 0 stops it. This feature is useful to collect information
Ingo Molnarc1a834d2007-06-01 00:47:16 -0700348 about timer usage patterns in kernel and userspace. This feature
349 is lightweight if enabled in the kernel config but not activated
350 (it defaults to deactivated on bootup and will only be activated
351 if some application like powertop activates it explicitly).
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800352
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700353config DEBUG_OBJECTS
354 bool "Debug object operations"
355 depends on DEBUG_KERNEL
356 help
357 If you say Y here, additional code will be inserted into the
358 kernel to track the life time of various objects and validate
359 the operations on those objects.
360
361config DEBUG_OBJECTS_SELFTEST
362 bool "Debug objects selftest"
363 depends on DEBUG_OBJECTS
364 help
365 This enables the selftest of the object debug code.
366
367config DEBUG_OBJECTS_FREE
368 bool "Debug objects in freed memory"
369 depends on DEBUG_OBJECTS
370 help
371 This enables checks whether a k/v free operation frees an area
372 which contains an object which has not been deactivated
373 properly. This can make kmalloc/kfree-intensive workloads
374 much slower.
375
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700376config DEBUG_OBJECTS_TIMERS
377 bool "Debug timer objects"
378 depends on DEBUG_OBJECTS
379 help
380 If you say Y here, additional code will be inserted into the
381 timer routines to track the life time of timer objects and
382 validate the timer operations.
383
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900384config DEBUG_OBJECTS_WORK
385 bool "Debug work objects"
386 depends on DEBUG_OBJECTS
387 help
388 If you say Y here, additional code will be inserted into the
389 work queue routines to track the life time of work objects and
390 validate the work operations.
391
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400392config DEBUG_OBJECTS_RCU_HEAD
393 bool "Debug RCU callbacks objects"
Mathieu Desnoyersfc2ecf72011-02-23 09:42:14 -0800394 depends on DEBUG_OBJECTS
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400395 help
396 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
397
Tejun Heoe2852ae2010-10-26 14:23:05 -0700398config DEBUG_OBJECTS_PERCPU_COUNTER
399 bool "Debug percpu counter objects"
400 depends on DEBUG_OBJECTS
401 help
402 If you say Y here, additional code will be inserted into the
403 percpu counter routines to track the life time of percpu counter
404 objects and validate the percpu counter operations.
405
Ingo Molnar3ae70202008-11-26 10:02:00 +0100406config DEBUG_OBJECTS_ENABLE_DEFAULT
407 int "debug_objects bootup default value (0-1)"
408 range 0 1
409 default "1"
410 depends on DEBUG_OBJECTS
411 help
412 Debug objects boot parameter default value
413
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800415 bool "Debug slab memory allocations"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200416 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 help
418 Say Y here to have the kernel do limited verification on memory
419 allocation as well as poisoning memory on free to catch use of freed
420 memory. This can make kmalloc/kfree-intensive workloads much slower.
421
Al Viro871751e2006-03-25 03:06:39 -0800422config DEBUG_SLAB_LEAK
423 bool "Memory leak debugging"
424 depends on DEBUG_SLAB
425
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700426config SLUB_DEBUG_ON
427 bool "SLUB debugging on by default"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200428 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700429 default n
430 help
431 Boot with debugging on by default. SLUB boots by default with
432 the runtime debug capabilities switched off. Enabling this is
433 equivalent to specifying the "slub_debug" parameter on boot.
434 There is no support for more fine grained debug control like
435 possible with slub_debug=xxx. SLUB debugging may be switched
436 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
437 "slub_debug=-".
438
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800439config SLUB_STATS
440 default n
441 bool "Enable SLUB performance statistics"
Christoph Lameterab4d5ed2010-10-05 13:57:26 -0500442 depends on SLUB && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800443 help
444 SLUB statistics are useful to debug SLUBs allocation behavior in
445 order find ways to optimize the allocator. This should never be
446 enabled for production use since keeping statistics slows down
447 the allocator by a few percentage points. The slabinfo command
448 supports the determination of the most active slabs to figure
449 out which slabs are relevant to a particular load.
450 Try running: slabinfo -DA
451
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100452config DEBUG_KMEMLEAK
453 bool "Kernel memory leak detector"
Laura Abbott029aeff2011-11-15 23:49:09 +0000454 depends on DEBUG_KERNEL && EXPERIMENTAL && \
Maxin Johnc0a5afb2011-03-29 00:15:55 +0300455 (X86 || ARM || PPC || MIPS || S390 || SPARC64 || SUPERH || MICROBLAZE || TILE)
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200456
Catalin Marinas79e0d9b2011-04-27 17:06:19 +0100457 select DEBUG_FS
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100458 select STACKTRACE if STACKTRACE_SUPPORT
459 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800460 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100461 help
462 Say Y here if you want to enable the memory leak
463 detector. The memory allocation/freeing is traced in a way
464 similar to the Boehm's conservative garbage collector, the
465 difference being that the orphan objects are not freed but
466 only shown in /sys/kernel/debug/kmemleak. Enabling this
467 feature will introduce an overhead to memory
468 allocations. See Documentation/kmemleak.txt for more
469 details.
470
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100471 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
472 of finding leaks due to the slab objects poisoning.
473
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100474 In order to access the kmemleak file, debugfs needs to be
475 mounted (usually at /sys/kernel/debug).
476
Catalin Marinasa9d90582009-06-25 10:16:11 +0100477config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
478 int "Maximum kmemleak early log entries"
479 depends on DEBUG_KMEMLEAK
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200480 range 200 40000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100481 default 400
482 help
483 Kmemleak must track all the memory allocations to avoid
484 reporting false positives. Since memory may be allocated or
485 freed before kmemleak is initialised, an early log buffer is
486 used to store these actions. If kmemleak reports "early log
487 buffer exceeded", please increase this value.
488
Catalin Marinas0822ee42009-06-11 13:24:14 +0100489config DEBUG_KMEMLEAK_TEST
490 tristate "Simple test for the kernel memory leak detector"
Daniel Baluta97182692011-04-04 15:06:44 -0700491 depends on DEBUG_KMEMLEAK && m
Catalin Marinas0822ee42009-06-11 13:24:14 +0100492 help
Daniel Baluta97182692011-04-04 15:06:44 -0700493 This option enables a module that explicitly leaks memory.
Catalin Marinas0822ee42009-06-11 13:24:14 +0100494
495 If unsure, say N.
496
Jason Baronab0155a2010-07-19 11:54:17 +0100497config DEBUG_KMEMLEAK_DEFAULT_OFF
498 bool "Default kmemleak to off"
499 depends on DEBUG_KMEMLEAK
500 help
501 Say Y here to disable kmemleak by default. It can then be enabled
502 on the command line via kmemleak=on.
503
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504config DEBUG_PREEMPT
505 bool "Debug preemptible kernel"
Kumar Gala01deab92009-10-16 07:21:39 +0000506 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 default y
508 help
509 If you say Y here then the kernel will use a debug variant of the
510 commonly used smp_processor_id() function and will print warnings
511 if kernel code uses it in a preemption-unsafe way. Also, the kernel
512 will detect preemption count underflows.
513
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700514config DEBUG_RT_MUTEXES
515 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700516 depends on DEBUG_KERNEL && RT_MUTEXES
517 help
518 This allows rt mutex semantics violations and rt mutex related
519 deadlocks (lockups) to be detected and reported automatically.
520
521config DEBUG_PI_LIST
522 bool
523 default y
524 depends on DEBUG_RT_MUTEXES
525
Thomas Gleixner61a87122006-06-27 02:54:56 -0700526config RT_MUTEX_TESTER
527 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700528 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700529 help
530 This option enables a rt-mutex tester.
531
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700533 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +0530535 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 help
537 Say Y here and build SMP to catch missing spinlock initialization
538 and certain other kinds of spinlock errors commonly made. This is
539 best used in conjunction with the NMI watchdog so that spinlock
540 deadlocks are also debuggable.
541
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700542config DEBUG_MUTEXES
543 bool "Mutex debugging: basic checks"
544 depends on DEBUG_KERNEL
545 help
546 This feature allows mutex semantics violations to be detected and
547 reported.
548
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700549config DEBUG_LOCK_ALLOC
550 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700551 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700552 select DEBUG_SPINLOCK
553 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700554 select LOCKDEP
555 help
556 This feature will check whether any held lock (spinlock, rwlock,
557 mutex or rwsem) is incorrectly freed by the kernel, via any of the
558 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
559 vfree(), etc.), whether a live lock is incorrectly reinitialized via
560 spin_lock_init()/mutex_init()/etc., or whether there is any lock
561 held during task exit.
562
563config PROVE_LOCKING
564 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700565 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700566 select LOCKDEP
567 select DEBUG_SPINLOCK
568 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700569 select DEBUG_LOCK_ALLOC
Steven Rostedt46b93b72010-08-31 16:35:20 -0400570 select TRACE_IRQFLAGS
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700571 default n
572 help
573 This feature enables the kernel to prove that all locking
574 that occurs in the kernel runtime is mathematically
575 correct: that under no circumstance could an arbitrary (and
576 not yet triggered) combination of observed locking
577 sequences (on an arbitrary number of CPUs, running an
578 arbitrary number of tasks and interrupt contexts) cause a
579 deadlock.
580
581 In short, this feature enables the kernel to report locking
582 related deadlocks before they actually occur.
583
584 The proof does not depend on how hard and complex a
585 deadlock scenario would be to trigger: how many
586 participant CPUs, tasks and irq-contexts would be needed
587 for it to trigger. The proof also does not depend on
588 timing: if a race and a resulting deadlock is possible
589 theoretically (no matter how unlikely the race scenario
590 is), it will be proven so and will immediately be
591 reported by the kernel (once the event is observed that
592 makes the deadlock theoretically possible).
593
594 If a deadlock is impossible (i.e. the locking rules, as
595 observed by the kernel, are mathematically correct), the
596 kernel reports nothing.
597
598 NOTE: this feature can also be enabled for rwlocks, mutexes
599 and rwsems - in which case all dependencies between these
600 different locking variants are observed and mapped too, and
601 the proof of observed correctness is also maintained for an
602 arbitrary combination of these separate locking variants.
603
604 For more details, see Documentation/lockdep-design.txt.
605
Paul E. McKenney632ee202010-02-22 17:04:45 -0800606config PROVE_RCU
607 bool "RCU debugging: prove RCU correctness"
608 depends on PROVE_LOCKING
609 default n
610 help
611 This feature enables lockdep extensions that check for correct
612 use of RCU APIs. This is currently under development. Say Y
613 if you want to debug RCU usage or help work on the PROVE_RCU
614 feature.
615
616 Say N if you are unsure.
617
Lai Jiangshan2b3fc352010-04-20 16:23:07 +0800618config PROVE_RCU_REPEATEDLY
619 bool "RCU debugging: don't disable PROVE_RCU on first splat"
620 depends on PROVE_RCU
621 default n
622 help
623 By itself, PROVE_RCU will disable checking upon issuing the
624 first warning (or "splat"). This feature prevents such
625 disabling, allowing multiple RCU-lockdep warnings to be printed
626 on a single reboot.
627
Paul E. McKenney2dfbf4d2010-09-15 23:30:48 -0700628 Say Y to allow multiple RCU-lockdep warnings per boot.
629
630 Say N if you are unsure.
631
Paul E. McKenneye3ebfb92012-07-02 14:42:01 -0700632config PROVE_RCU_DELAY
633 bool "RCU debugging: preemptible RCU race provocation"
634 depends on DEBUG_KERNEL && PREEMPT_RCU
635 default n
636 help
637 There is a class of races that involve an unlikely preemption
638 of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
639 been set to INT_MIN. This feature inserts a delay at that
640 point to increase the probability of these races.
641
642 Say Y to increase probability of preemption of __rcu_read_unlock().
643
644 Say N if you are unsure.
645
Paul E. McKenneyca5ecdd2010-04-28 14:39:09 -0700646config SPARSE_RCU_POINTER
647 bool "RCU debugging: sparse-based checks for pointer usage"
648 default n
649 help
650 This feature enables the __rcu sparse annotation for
651 RCU-protected pointers. This annotation will cause sparse
652 to flag any non-RCU used of annotated pointers. This can be
653 helpful when debugging RCU usage. Please note that this feature
654 is not intended to enforce code cleanliness; it is instead merely
655 a debugging aid.
656
657 Say Y to make sparse flag questionable use of RCU-protected pointers
658
Lai Jiangshan2b3fc352010-04-20 16:23:07 +0800659 Say N if you are unsure.
660
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700661config LOCKDEP
662 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700663 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700664 select STACKTRACE
Michal Simek79aac882010-05-25 11:33:26 +0200665 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700666 select KALLSYMS
667 select KALLSYMS_ALL
668
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700669config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700670 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700671 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
672 select LOCKDEP
673 select DEBUG_SPINLOCK
674 select DEBUG_MUTEXES
675 select DEBUG_LOCK_ALLOC
676 default n
677 help
678 This feature enables tracking lock contention points
679
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700680 For more details, see Documentation/lockstat.txt
681
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +0100682 This also enables lock events required by "perf lock",
683 subcommand of perf.
684 If you want to use "perf lock", you also need to turn on
685 CONFIG_EVENT_TRACING.
Hitoshi Mitake84c6f882010-02-04 16:08:15 +0900686
687 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +0100688 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
Hitoshi Mitake84c6f882010-02-04 16:08:15 +0900689
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700690config DEBUG_LOCKDEP
691 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700692 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700693 help
694 If you say Y here, the lock dependency engine will do
695 additional runtime checks to debug itself, at the price
696 of more runtime overhead.
697
698config TRACE_IRQFLAGS
699 bool
Steven Rostedt46b93b72010-08-31 16:35:20 -0400700 help
701 Enables hooks to interrupt enabling and disabling for
702 either tracing or lock debugging.
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700703
Frederic Weisbeckerd902db12011-06-08 19:31:56 +0200704config DEBUG_ATOMIC_SLEEP
705 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +0200706 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 depends on DEBUG_KERNEL
708 help
709 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +0200710 noisy if they are called inside atomic sections: when a spinlock is
711 held, inside an rcu read side critical section, inside preempt disabled
712 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700714config DEBUG_LOCKING_API_SELFTESTS
715 bool "Locking API boot-time self-tests"
716 depends on DEBUG_KERNEL
717 help
718 Say Y here if you want the kernel to run a short self-test during
719 bootup. The self-test checks whether common types of locking bugs
720 are detected by debugging mechanisms or not. (if you disable
721 lock debugging then those bugs wont be detected of course.)
722 The following locking APIs are covered: spinlocks, rwlocks,
723 mutexes and rwsems.
724
Ingo Molnar8637c092006-07-03 00:24:38 -0700725config STACKTRACE
726 bool
727 depends on STACKTRACE_SUPPORT
728
Stephen Boyd5ca43f62011-05-24 17:13:36 -0700729config DEBUG_STACK_USAGE
730 bool "Stack utilization instrumentation"
Tony Lucke9c31b32012-07-18 10:35:05 -0700731 depends on DEBUG_KERNEL && !IA64 && !PARISC
Stephen Boyd5ca43f62011-05-24 17:13:36 -0700732 help
733 Enables the display of the minimum amount of free stack which each
734 task has ever had available in the sysrq-T and sysrq-P debug output.
735
736 This option will slow down process creation somewhat.
737
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738config DEBUG_KOBJECT
739 bool "kobject debugging"
740 depends on DEBUG_KERNEL
741 help
742 If you say Y here, some extra kobject debugging messages will be sent
743 to the syslog.
744
745config DEBUG_HIGHMEM
746 bool "Highmem debugging"
747 depends on DEBUG_KERNEL && HIGHMEM
748 help
749 This options enables addition error checking for high memory systems.
750 Disable for production systems.
751
752config DEBUG_BUGVERBOSE
David Rientjes6a108a12011-01-20 14:44:16 -0800753 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
Matt Mackallc8538a72005-05-01 08:59:01 -0700754 depends on BUG
David Howellsb920de12008-02-08 04:19:31 -0800755 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
Chris Metcalf3cc39b32011-06-01 16:06:04 -0400756 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300 || TILE
Alexey Dobriyan8420e7e2009-12-14 18:00:25 -0800757 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 help
759 Say Y here to make BUG() panics output the file name and line number
760 of the BUG call as well as the EIP and oops trace. This aids
761 debugging but costs about 70-100K of memory.
762
763config DEBUG_INFO
764 bool "Compile the kernel with debug info"
765 depends on DEBUG_KERNEL
766 help
767 If you say Y here the resulting kernel image will include
768 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600769 This adds debug symbols to the kernel and modules (gcc -g), and
770 is needed if you intend to use kernel crashdump or binary object
771 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 Say Y here only if you plan to debug the kernel.
773
774 If unsure, say N.
775
Andi Kleend6f4ceb2010-07-14 15:43:52 +0200776config DEBUG_INFO_REDUCED
777 bool "Reduce debugging information"
778 depends on DEBUG_INFO
779 help
780 If you say Y here gcc is instructed to generate less debugging
781 information for structure types. This means that tools that
782 need full debugging information (like kgdb or systemtap) won't
783 be happy. But if you merely need debugging information to
784 resolve line numbers there is no loss. Advantage is that
785 build directory object sizes shrink dramatically over a full
786 DEBUG_INFO build and compile times are reduced too.
787 Only works with newer gcc versions.
788
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800789config DEBUG_VM
790 bool "Debug VM"
791 depends on DEBUG_KERNEL
792 help
Nick Piggin13e74442006-01-06 00:10:58 -0800793 Enable this to turn on extended checks in the virtual-memory system
794 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800795
796 If unsure, say N.
797
Jiri Slaby59ea7462008-06-12 13:56:40 +0200798config DEBUG_VIRTUAL
799 bool "Debug VM translations"
800 depends on DEBUG_KERNEL && X86
801 help
802 Enable some costly sanity checks in virtual to page code. This can
803 catch mistakes with virt_to_page() and friends.
804
805 If unsure, say N.
806
David Howells8feae132009-01-08 12:04:47 +0000807config DEBUG_NOMMU_REGIONS
808 bool "Debug the global anon/private NOMMU mapping region tree"
809 depends on DEBUG_KERNEL && !MMU
810 help
811 This option causes the global tree of anonymous and private mapping
812 regions to be regularly checked for invalid topology.
813
Dave Hansenad775f52008-02-15 14:38:01 -0800814config DEBUG_WRITECOUNT
815 bool "Debug filesystem writers count"
816 depends on DEBUG_KERNEL
817 help
818 Enable this to catch wrong use of the writers count in struct
819 vfsmount. This will increase the size of each file struct by
820 32 bits.
821
822 If unsure, say N.
823
Mel Gorman6b74ab92008-07-23 21:26:49 -0700824config DEBUG_MEMORY_INIT
David Rientjes6a108a12011-01-20 14:44:16 -0800825 bool "Debug memory initialisation" if EXPERT
826 default !EXPERT
Mel Gorman6b74ab92008-07-23 21:26:49 -0700827 help
828 Enable this for additional checks during memory initialisation.
829 The sanity checks verify aspects of the VM such as the memory model
830 and other information provided by the architecture. Verbose
831 information will be printed at KERN_DEBUG loglevel depending
832 on the mminit_loglevel= command-line option.
833
834 If unsure, say Y
835
Dave Jones199a9af2006-09-29 01:59:00 -0700836config DEBUG_LIST
837 bool "Debug linked list manipulation"
838 depends on DEBUG_KERNEL
839 help
840 Enable this to turn on extended checks in the linked-list
841 walking routines.
842
843 If unsure, say N.
844
Artem Bityutskiy6d411e62010-10-26 14:23:05 -0700845config TEST_LIST_SORT
846 bool "Linked list sorting test"
847 depends on DEBUG_KERNEL
848 help
849 Enable this to turn on 'list_sort()' function test. This test is
850 executed only once during system boot, so affects only boot time.
851
852 If unsure, say N.
853
Jens Axboed6ec0842007-10-22 20:01:06 +0200854config DEBUG_SG
855 bool "Debug SG table operations"
856 depends on DEBUG_KERNEL
857 help
858 Enable this to turn on checks on scatter-gather tables. This can
859 help find problems with drivers that do not properly initialize
860 their sg tables.
861
862 If unsure, say N.
863
Arjan van de Ven1b2439d2008-08-15 15:29:38 -0700864config DEBUG_NOTIFIERS
865 bool "Debug notifier call chains"
866 depends on DEBUG_KERNEL
867 help
868 Enable this to turn on sanity checking for notifier call chains.
869 This is most useful for kernel developers to make sure that
870 modules properly unregister themselves from notifier chains.
871 This is a relatively cheap check but if you care about maximum
872 performance, say N.
873
David Howellse0e81732009-09-02 09:13:40 +0100874config DEBUG_CREDENTIALS
875 bool "Debug credential management"
876 depends on DEBUG_KERNEL
877 help
878 Enable this to turn on some debug checking for credential
879 management. The additional code keeps track of the number of
880 pointers from task_structs to any given cred struct, and checks to
881 see that this number never exceeds the usage count of the cred
882 struct.
883
884 Furthermore, if SELinux is enabled, this also checks that the
885 security pointer in the cred struct is never seen to be invalid.
886
887 If unsure, say N.
888
Jeff Mahoney64dec402009-01-16 13:23:35 -0500889#
890# Select this config option from the architecture Kconfig, if it
Justin P. Mattock52288b62011-08-21 20:02:13 -0700891# is preferred to always offer frame pointers as a config
Jeff Mahoney64dec402009-01-16 13:23:35 -0500892# option on the architecture (regardless of KERNEL_DEBUG):
893#
894config ARCH_WANT_FRAME_POINTERS
895 bool
896 help
897
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898config FRAME_POINTER
899 bool "Compile the kernel with frame pointers"
David Howellsb920de12008-02-08 04:19:31 -0800900 depends on DEBUG_KERNEL && \
Geert Uytterhoeven73020412011-01-22 22:35:38 +0100901 (CRIS || M68K || FRV || UML || \
Ingo Molnarda4276b2009-01-07 11:05:10 +0100902 AVR32 || SUPERH || BLACKFIN || MN10300) || \
903 ARCH_WANT_FRAME_POINTERS
904 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 help
Ingo Molnarda4276b2009-01-07 11:05:10 +0100906 If you say Y here the resulting kernel image will be slightly
907 larger and slower, but it gives very useful debugging information
908 in case of kernel bugs. (precise oopses/stacktraces/warnings)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700910config BOOT_PRINTK_DELAY
911 bool "Delay each boot printk message by N milliseconds"
912 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
913 help
914 This build option allows you to read kernel boot messages
915 by inserting a short delay after each one. The delay is
916 specified in milliseconds on the kernel command line,
917 using "boot_delay=N".
918
919 It is likely that you would also need to use "lpj=M" to preset
920 the "loops per jiffie" value.
921 See a previous boot log for the "lpj" value to use for your
922 system, and then set "lpj=M" before setting "boot_delay=N".
923 NOTE: Using this option may adversely affect SMP systems.
924 I.e., processors other than the first one may not boot up.
Anton Blanchard8edbb832011-07-05 13:32:40 +1000925 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700926 what it believes to be lockup conditions.
927
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800928config RCU_TORTURE_TEST
929 tristate "torture tests for RCU"
930 depends on DEBUG_KERNEL
931 default n
932 help
933 This option provides a kernel module that runs torture tests
934 on the RCU infrastructure. The kernel module may be built
935 after the fact on the running kernel to be tested, if desired.
936
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700937 Say Y here if you want RCU torture tests to be built into
938 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800939 Say M if you want the RCU torture tests to build as a module.
940 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700941
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700942config RCU_TORTURE_TEST_RUNNABLE
943 bool "torture tests for RCU runnable by default"
944 depends on RCU_TORTURE_TEST = y
945 default n
946 help
947 This option provides a way to build the RCU torture tests
948 directly into the kernel without them starting up at boot
949 time. You can use /proc/sys/kernel/rcutorture_runnable
950 to manually override this setting. This /proc file is
951 available only when the RCU torture tests have been built
952 into the kernel.
953
954 Say Y here if you want the RCU torture tests to start during
955 boot (you probably don't).
956 Say N here if you want the RCU torture tests to start only
957 after being manually enabled via /proc.
958
Paul E. McKenneyb1637602010-06-02 16:21:38 -0700959config RCU_CPU_STALL_TIMEOUT
960 int "RCU CPU stall timeout in seconds"
Paul E. McKenneya00e0d712011-02-08 17:14:39 -0800961 depends on TREE_RCU || TREE_PREEMPT_RCU
Paul E. McKenneyb1637602010-06-02 16:21:38 -0700962 range 3 300
963 default 60
964 help
965 If a given RCU grace period extends more than the specified
966 number of seconds, a CPU stall warning is printed. If the
967 RCU grace period persists, additional CPU stall warnings are
968 printed at more widely spaced intervals.
969
Paul E. McKenney1ed509a2010-02-22 17:05:05 -0800970config RCU_CPU_STALL_VERBOSE
971 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
Paul E. McKenneya00e0d712011-02-08 17:14:39 -0800972 depends on TREE_PREEMPT_RCU
Paul E. McKenney55ec9362010-04-13 12:22:33 -0700973 default y
Paul E. McKenney1ed509a2010-02-22 17:05:05 -0800974 help
975 This option causes RCU to printk detailed per-task information
976 for any tasks that are stalling the current RCU grace period.
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100977
978 Say N if you are unsure.
979
Paul E. McKenney1ed509a2010-02-22 17:05:05 -0800980 Say Y if you want to enable such checks.
981
Paul E. McKenneya858af22012-01-16 13:29:10 -0800982config RCU_CPU_STALL_INFO
983 bool "Print additional diagnostics on RCU CPU stall"
984 depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
985 default n
986 help
987 For each stalled CPU that is aware of the current RCU grace
988 period, print out additional per-CPU diagnostic information
989 regarding scheduling-clock ticks, idle state, and,
990 for RCU_FAST_NO_HZ kernels, idle-entry state.
991
992 Say N if you are unsure.
993
994 Say Y if you want to enable such diagnostics.
995
Paul E. McKenney5c8806a2012-01-06 15:10:44 -0800996config RCU_TRACE
997 bool "Enable tracing for RCU"
998 depends on DEBUG_KERNEL
999 help
1000 This option provides tracing in RCU which presents stats
1001 in debugfs for debugging RCU implementation.
1002
1003 Say Y here if you want to enable RCU tracing
1004 Say N if you are unsure.
1005
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +01001006config KPROBES_SANITY_TEST
1007 bool "Kprobes sanity tests"
1008 depends on DEBUG_KERNEL
1009 depends on KPROBES
1010 default n
1011 help
1012 This option provides for testing basic kprobes functionality on
1013 boot. A sample kprobe, jprobe and kretprobe are inserted and
1014 verified for functionality.
1015
1016 Say N if you are unsure.
1017
Arjan van de Ven6dab2772008-01-30 13:33:08 +01001018config BACKTRACE_SELF_TEST
1019 tristate "Self test for the backtrace code"
1020 depends on DEBUG_KERNEL
1021 default n
1022 help
1023 This option provides a kernel module that can be used to test
1024 the kernel stack backtrace code. This option is not useful
1025 for distributions or general kernels, but only for kernel
1026 developers working on architecture code.
1027
Vegard Nossumad118c52008-06-27 18:04:48 +02001028 Note that if you want to also test saved backtraces, you will
1029 have to enable STACKTRACE as well.
1030
Arjan van de Ven6dab2772008-01-30 13:33:08 +01001031 Say N if you are unsure.
1032
Tejun Heo870d6652008-08-25 19:47:25 +09001033config DEBUG_BLOCK_EXT_DEVT
1034 bool "Force extended block device numbers and spread them"
1035 depends on DEBUG_KERNEL
1036 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +02001037 default n
Tejun Heo870d6652008-08-25 19:47:25 +09001038 help
Tejun Heo0e11e342008-10-13 10:46:01 +02001039 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1040 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1041 YOU ARE DOING. Distros, please enable this and fix whatever
1042 is broken.
1043
Tejun Heo870d6652008-08-25 19:47:25 +09001044 Conventionally, block device numbers are allocated from
1045 predetermined contiguous area. However, extended block area
1046 may introduce non-contiguous block device numbers. This
1047 option forces most block device numbers to be allocated from
1048 the extended space and spreads them to discover kernel or
1049 userland code paths which assume predetermined contiguous
1050 device number allocation.
1051
Tejun Heo55dc7db2008-09-01 13:44:35 +02001052 Note that turning on this debug option shuffles all the
1053 device numbers for all IDE and SCSI devices including libata
1054 ones, so root partition specified using device number
1055 directly (via rdev or root=MAJ:MIN) won't work anymore.
1056 Textual device names (root=/dev/sdXn) will continue to work.
1057
Tejun Heo870d6652008-08-25 19:47:25 +09001058 Say N if you are unsure.
1059
Tejun Heo7c756e62009-06-24 15:13:50 +09001060config DEBUG_FORCE_WEAK_PER_CPU
1061 bool "Force weak per-cpu definitions"
1062 depends on DEBUG_KERNEL
1063 help
1064 s390 and alpha require percpu variables in modules to be
1065 defined weak to work around addressing range issue which
1066 puts the following two restrictions on percpu variable
1067 definitions.
1068
1069 1. percpu symbols must be unique whether static or not
1070 2. percpu variables can't be defined inside a function
1071
1072 To ensure that generic code follows the above rules, this
1073 option forces all percpu variables to be defined as weak.
1074
Stephen Boyd44ec7ab2011-05-24 17:13:32 -07001075config DEBUG_PER_CPU_MAPS
1076 bool "Debug access to per_cpu maps"
1077 depends on DEBUG_KERNEL
1078 depends on SMP
1079 help
1080 Say Y to verify that the per_cpu map being accessed has
1081 been set up. This adds a fair amount of code to kernel memory
1082 and decreases performance.
1083
1084 Say N if unsure.
1085
Ankita Garg8bb31b92006-10-02 02:17:36 -07001086config LKDTM
1087 tristate "Linux Kernel Dump Test Tool Module"
Simon Kagstrom0347af42010-03-05 13:42:49 -08001088 depends on DEBUG_FS
Chris Snookfddd9cf2008-02-23 15:23:26 -08001089 depends on BLOCK
Ankita Garg8bb31b92006-10-02 02:17:36 -07001090 default n
1091 help
1092 This module enables testing of the different dumping mechanisms by
1093 inducing system failures at predefined crash points.
1094 If you don't need it: say N
1095 Choose M here to compile this code as a module. The module will be
1096 called lkdtm.
1097
1098 Documentation on how to use the module can be found in
Simon Kagstrom0347af42010-03-05 13:42:49 -08001099 Documentation/fault-injection/provoke-crashes.txt
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001100
Akinobu Mita8d438282012-07-30 14:43:02 -07001101config NOTIFIER_ERROR_INJECTION
1102 tristate "Notifier error injection"
1103 depends on DEBUG_KERNEL
1104 select DEBUG_FS
1105 help
1106 This option provides the ability to inject artifical errors to
1107 specified notifier chain callbacks. It is useful to test the error
1108 handling of notifier call chain failures.
1109
1110 Say N if unsure.
1111
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001112config CPU_NOTIFIER_ERROR_INJECT
1113 tristate "CPU notifier error injection module"
Akinobu Mitaf5a9f522012-07-30 14:43:03 -07001114 depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001115 help
1116 This option provides a kernel module that can be used to test
Akinobu Mitaf5a9f522012-07-30 14:43:03 -07001117 the error handling of the cpu notifiers by injecting artifical
1118 errors to CPU notifier chain callbacks. It is controlled through
1119 debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu
1120
1121 If the notifier call chain should be failed with some events
1122 notified, write the error code to "actions/<notifier event>/error".
1123
1124 Example: Inject CPU offline error (-1 == -EPERM)
1125
1126 # cd /sys/kernel/debug/notifier-error-inject/cpu
1127 # echo -1 > actions/CPU_DOWN_PREPARE/error
1128 # echo 0 > /sys/devices/system/cpu/cpu1/online
1129 bash: echo: write error: Operation not permitted
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001130
1131 To compile this code as a module, choose M here: the module will
1132 be called cpu-notifier-error-inject.
1133
1134 If unsure, say N.
1135
Akinobu Mita048b9c32012-07-30 14:43:07 -07001136config PM_NOTIFIER_ERROR_INJECT
1137 tristate "PM notifier error injection module"
1138 depends on PM && NOTIFIER_ERROR_INJECTION
1139 default m if PM_DEBUG
1140 help
1141 This option provides the ability to inject artifical errors to
1142 PM notifier chain callbacks. It is controlled through debugfs
1143 interface /sys/kernel/debug/notifier-error-inject/pm
1144
1145 If the notifier call chain should be failed with some events
1146 notified, write the error code to "actions/<notifier event>/error".
1147
1148 Example: Inject PM suspend error (-12 = -ENOMEM)
1149
1150 # cd /sys/kernel/debug/notifier-error-inject/pm/
1151 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1152 # echo mem > /sys/power/state
1153 bash: echo: write error: Cannot allocate memory
1154
1155 To compile this code as a module, choose M here: the module will
1156 be called pm-notifier-error-inject.
1157
1158 If unsure, say N.
1159
Akinobu Mita9579f5b2012-07-30 14:43:10 -07001160config MEMORY_NOTIFIER_ERROR_INJECT
1161 tristate "Memory hotplug notifier error injection module"
1162 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
1163 help
1164 This option provides the ability to inject artifical errors to
1165 memory hotplug notifier chain callbacks. It is controlled through
1166 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
1167
1168 If the notifier call chain should be failed with some events
1169 notified, write the error code to "actions/<notifier event>/error".
1170
1171 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
1172
1173 # cd /sys/kernel/debug/notifier-error-inject/memory
1174 # echo -12 > actions/MEM_GOING_OFFLINE/error
1175 # echo offline > /sys/devices/system/memory/memoryXXX/state
1176 bash: echo: write error: Cannot allocate memory
1177
1178 To compile this code as a module, choose M here: the module will
1179 be called pSeries-reconfig-notifier-error-inject.
1180
1181 If unsure, say N.
1182
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001183config PSERIES_RECONFIG_NOTIFIER_ERROR_INJECT
1184 tristate "pSeries reconfig notifier error injection module"
1185 depends on PPC_PSERIES && NOTIFIER_ERROR_INJECTION
1186 help
1187 This option provides the ability to inject artifical errors to
1188 pSeries reconfig notifier chain callbacks. It is controlled
1189 through debugfs interface under
1190 /sys/kernel/debug/notifier-error-inject/pSeries-reconfig/
1191
1192 If the notifier call chain should be failed with some events
1193 notified, write the error code to "actions/<notifier event>/error".
1194
1195 To compile this code as a module, choose M here: the module will
1196 be called memory-notifier-error-inject.
1197
1198 If unsure, say N.
1199
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001200config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001201 bool "Fault-injection framework"
1202 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001203 help
1204 Provide fault-injection framework.
1205 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001206
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001207config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001208 bool "Fault-injection capability for kmalloc"
1209 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001210 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001211 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001212 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001213
Akinobu Mita933e3122006-12-08 02:39:45 -08001214config FAIL_PAGE_ALLOC
1215 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001216 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001217 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001218 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001219
Akinobu Mitac17bb492006-12-08 02:39:46 -08001220config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001221 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001222 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001223 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001224 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001225
Jens Axboe581d4e22008-09-14 05:56:33 -07001226config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d014392010-07-21 16:05:53 +09001227 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001228 depends on FAULT_INJECTION && BLOCK
1229 help
1230 Provide fault-injection capability on end IO handling. This
1231 will make the block layer "forget" an interrupt as configured,
1232 thus exercising the error handling.
1233
1234 Only works with drivers that use the generic timeout handling,
1235 for others it wont do anything.
1236
Per Forlin1b676f72011-08-19 14:52:37 +02001237config FAIL_MMC_REQUEST
1238 bool "Fault-injection capability for MMC IO"
1239 select DEBUG_FS
1240 depends on FAULT_INJECTION && MMC
1241 help
1242 Provide fault-injection capability for MMC IO.
1243 This will make the mmc core return data errors. This is
1244 useful to test the error handling in the mmc block device
1245 and to test how the mmc host driver handles retries from
1246 the block device.
1247
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001248config FAULT_INJECTION_DEBUG_FS
1249 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001250 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001251 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001252 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -08001253
1254config FAULT_INJECTION_STACKTRACE_FILTER
1255 bool "stacktrace filter for fault-injection capabilities"
1256 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001257 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001258 select STACKTRACE
Arnd Bergmann89bace62011-06-10 14:12:21 +00001259 select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
Akinobu Mita1df49002007-02-20 13:57:56 -08001260 help
1261 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001262
Arjan van de Ven97455122008-01-25 21:08:34 +01001263config LATENCYTOP
1264 bool "Latency measuring infrastructure"
Randy Dunlap625fdca2010-08-12 12:31:21 -07001265 depends on HAVE_LATENCYTOP_SUPPORT
1266 depends on DEBUG_KERNEL
1267 depends on STACKTRACE_SUPPORT
1268 depends on PROC_FS
Arnd Bergmann89bace62011-06-10 14:12:21 +00001269 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
Arjan van de Ven97455122008-01-25 21:08:34 +01001270 select KALLSYMS
1271 select KALLSYMS_ALL
1272 select STACKTRACE
1273 select SCHEDSTATS
1274 select SCHED_DEBUG
Arjan van de Ven97455122008-01-25 21:08:34 +01001275 help
1276 Enable this option if you want to use the LatencyTOP tool
1277 to find out which userspace is blocking on what kernel operations.
1278
Akinobu Mita6a11f752009-03-31 15:23:17 -07001279source mm/Kconfig.debug
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001280source kernel/trace/Kconfig
1281
Bernhard Kaindlf212ec42008-01-30 13:34:11 +01001282config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +01001283 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +01001284 depends on PCI && X86
1285 help
1286 If you want to debug problems which hang or crash the kernel early
1287 on boot and the crashing machine has a FireWire port, you can use
1288 this feature to remotely access the memory of the crashed machine
1289 over FireWire. This employs remote DMA as part of the OHCI1394
1290 specification which is now the standard for FireWire controllers.
1291
1292 With remote DMA, you can monitor the printk buffer remotely using
1293 firescope and access all memory below 4GB using fireproxy from gdb.
1294 Even controlling a kernel debugger is possible using remote DMA.
1295
1296 Usage:
1297
1298 If ohci1394_dma=early is used as boot parameter, it will initialize
1299 all OHCI1394 controllers which are found in the PCI config space.
1300
1301 As all changes to the FireWire bus such as enabling and disabling
1302 devices cause a bus reset and thereby disable remote DMA for all
1303 devices, be sure to have the cable plugged and FireWire enabled on
1304 the debugging host before booting the debug target for debugging.
1305
1306 This code (~1k) is freed after boot. By then, the firewire stack
1307 in charge of the OHCI-1394 controllers should be used instead.
1308
1309 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +01001310
Stefan Richter080de8c2008-02-28 20:54:43 +01001311config FIREWIRE_OHCI_REMOTE_DMA
1312 bool "Remote debugging over FireWire with firewire-ohci"
1313 depends on FIREWIRE_OHCI
1314 help
1315 This option lets you use the FireWire bus for remote debugging
1316 with help of the firewire-ohci driver. It enables unfiltered
1317 remote DMA in firewire-ohci.
1318 See Documentation/debugging-via-ohci1394.txt for more information.
1319
1320 If unsure, say N.
1321
Randy Dunlap152de302009-02-20 15:38:47 -08001322config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -07001323 bool "Build targets in Documentation/ tree"
1324 depends on HEADERS_CHECK
1325 help
1326 This option attempts to build objects from the source files in the
1327 kernel Documentation/ tree.
1328
1329 Say N if you are unsure.
1330
Jason Barone9d376f2009-02-05 11:51:38 -05001331config DYNAMIC_DEBUG
Jason Baron86151fd2009-02-05 11:53:15 -05001332 bool "Enable dynamic printk() support"
Jason Baron346e15b2008-08-12 16:46:19 -04001333 default n
1334 depends on PRINTK
Jason Baron86151fd2009-02-05 11:53:15 -05001335 depends on DEBUG_FS
Jason Baron346e15b2008-08-12 16:46:19 -04001336 help
1337
1338 Compiles debug level messages into the kernel, which would not
1339 otherwise be available at runtime. These messages can then be
Jason Baron86151fd2009-02-05 11:53:15 -05001340 enabled/disabled based on various levels of scope - per source file,
1341 function, module, format string, and line number. This mechanism
Jim Cromie29e36c92012-04-27 14:30:41 -06001342 implicitly compiles in all pr_debug() and dev_dbg() calls, which
1343 enlarges the kernel text size by about 2%.
1344
1345 If a source file is compiled with DEBUG flag set, any
1346 pr_debug() calls in it are enabled by default, but can be
1347 disabled at runtime as below. Note that DEBUG flag is
1348 turned on by many CONFIG_*DEBUG* options.
Jason Baron346e15b2008-08-12 16:46:19 -04001349
1350 Usage:
1351
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001352 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
Jason Baron86151fd2009-02-05 11:53:15 -05001353 which is contained in the 'debugfs' filesystem. Thus, the debugfs
1354 filesystem must first be mounted before making use of this feature.
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001355 We refer the control file as: <debugfs>/dynamic_debug/control. This
Jason Baron86151fd2009-02-05 11:53:15 -05001356 file contains a list of the debug statements that can be enabled. The
1357 format for each line of the file is:
Jason Baron346e15b2008-08-12 16:46:19 -04001358
Jason Baron86151fd2009-02-05 11:53:15 -05001359 filename:lineno [module]function flags format
Jason Baron346e15b2008-08-12 16:46:19 -04001360
Jason Baron86151fd2009-02-05 11:53:15 -05001361 filename : source file of the debug statement
1362 lineno : line number of the debug statement
1363 module : module that contains the debug statement
1364 function : function that contains the debug statement
Jim Cromie29e36c92012-04-27 14:30:41 -06001365 flags : '=p' means the line is turned 'on' for printing
Jason Baron86151fd2009-02-05 11:53:15 -05001366 format : the format used for the debug statement
Jason Baron346e15b2008-08-12 16:46:19 -04001367
1368 From a live system:
1369
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001370 nullarbor:~ # cat <debugfs>/dynamic_debug/control
Jason Baron86151fd2009-02-05 11:53:15 -05001371 # filename:lineno [module]function flags format
Jim Cromie29e36c92012-04-27 14:30:41 -06001372 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
1373 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
1374 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
Jason Baron346e15b2008-08-12 16:46:19 -04001375
Jason Baron86151fd2009-02-05 11:53:15 -05001376 Example usage:
Jason Baron346e15b2008-08-12 16:46:19 -04001377
Jason Baron86151fd2009-02-05 11:53:15 -05001378 // enable the message at line 1603 of file svcsock.c
1379 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001380 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001381
Jason Baron86151fd2009-02-05 11:53:15 -05001382 // enable all the messages in file svcsock.c
1383 nullarbor:~ # echo -n 'file svcsock.c +p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001384 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001385
Jason Baron86151fd2009-02-05 11:53:15 -05001386 // enable all the messages in the NFS server module
1387 nullarbor:~ # echo -n 'module nfsd +p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001388 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001389
Jason Baron86151fd2009-02-05 11:53:15 -05001390 // enable all 12 messages in the function svc_process()
1391 nullarbor:~ # echo -n 'func svc_process +p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001392 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001393
Jason Baron86151fd2009-02-05 11:53:15 -05001394 // disable all 12 messages in the function svc_process()
1395 nullarbor:~ # echo -n 'func svc_process -p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001396 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001397
Jason Baron86151fd2009-02-05 11:53:15 -05001398 See Documentation/dynamic-debug-howto.txt for additional information.
Jason Baron346e15b2008-08-12 16:46:19 -04001399
Joerg Roedel5ee00bd2009-01-09 12:14:24 +01001400config DMA_API_DEBUG
1401 bool "Enable debugging of DMA-API usage"
1402 depends on HAVE_DMA_API_DEBUG
1403 help
1404 Enable this option to debug the use of the DMA API by device drivers.
1405 With this option you will be able to detect common bugs in device
1406 drivers like double-freeing of DMA mappings or freeing mappings that
1407 were never allocated.
1408 This option causes a performance degredation. Use only if you want
1409 to debug device drivers. If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -04001410
Luca Barbieri86a89382010-02-24 10:54:24 +01001411config ATOMIC64_SELFTEST
1412 bool "Perform an atomic64_t self-test at boot"
1413 help
1414 Enable this option to test the atomic64_t functions at boot.
1415
1416 If unsure, say N.
1417
Dan Williams400fb7f2010-10-07 15:25:04 -07001418config ASYNC_RAID6_TEST
1419 tristate "Self test for hardware accelerated raid6 recovery"
1420 depends on ASYNC_RAID6_RECOV
1421 select ASYNC_MEMCPY
1422 ---help---
1423 This is a one-shot self test that permutes through the
1424 recovery of all the possible two disk failure scenarios for a
1425 N-disk array. Recovery is performed with the asynchronous
1426 raid6 recovery routines, and will optionally use an offload
1427 engine if one is available.
1428
1429 If unsure, say N.
1430
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001431source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02001432
1433source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001434
1435source "lib/Kconfig.kmemcheck"
Alexey Dobriyan33ee3b22011-03-22 16:34:40 -07001436
1437config TEST_KSTRTOX
1438 tristate "Test kstrto*() family of functions at runtime"