blob: 28be08c09babda27bb77959538c9645962f84d75 [file] [log] [blame]
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
Greg Kroah-Hartman6ae14172012-12-21 15:16:45 -0800137 __init, __cpuinit, 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
Jan Beulich8f1f66e2012-10-04 17:13:17 -0700199 def_bool y
200 depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG
201 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700202
Don Zickusfef2c9b2011-03-22 16:34:16 -0700203config BOOTPARAM_HARDLOCKUP_PANIC
204 bool "Panic (Reboot) On Hard Lockups"
Jan Beulich8f1f66e2012-10-04 17:13:17 -0700205 depends on HARDLOCKUP_DETECTOR
Don Zickusfef2c9b2011-03-22 16:34:16 -0700206 help
207 Say Y here to enable the kernel to panic on "hard lockups",
208 which are bugs that cause the kernel to loop in kernel
Fernando Luis Vázquez Cao5f329082012-02-09 17:42:21 -0500209 mode with interrupts disabled for more than 10 seconds (configurable
210 using the watchdog_thresh sysctl).
Don Zickusfef2c9b2011-03-22 16:34:16 -0700211
212 Say N if unsure.
213
214config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
215 int
Jan Beulich8f1f66e2012-10-04 17:13:17 -0700216 depends on HARDLOCKUP_DETECTOR
Don Zickusfef2c9b2011-03-22 16:34:16 -0700217 range 0 1
218 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
219 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
220
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200221config BOOTPARAM_SOFTLOCKUP_PANIC
222 bool "Panic (Reboot) On Soft Lockups"
Frederic Weisbecker89d7ce22010-05-13 00:27:20 +0200223 depends on LOCKUP_DETECTOR
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200224 help
225 Say Y here to enable the kernel to panic on "soft lockups",
226 which are bugs that cause the kernel to loop in kernel
Fernando Luis Vázquez Cao5f329082012-02-09 17:42:21 -0500227 mode for more than 20 seconds (configurable using the watchdog_thresh
228 sysctl), without giving other tasks a chance to run.
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200229
230 The panic can be used in combination with panic_timeout,
231 to cause the system to reboot automatically after a
232 lockup has been detected. This feature is useful for
233 high-availability systems that have uptime guarantees and
234 where a lockup must be resolved ASAP.
235
236 Say N if unsure.
237
238config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
239 int
Frederic Weisbeckere16bb1d2010-05-15 22:30:22 +0200240 depends on LOCKUP_DETECTOR
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200241 range 0 1
242 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
243 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
244
Kyle McMartin2a01bb32012-04-11 08:15:29 -0400245config PANIC_ON_OOPS
Kyle McMartin76e84022013-02-21 16:43:04 -0800246 bool "Panic on Oops"
Kyle McMartin2a01bb32012-04-11 08:15:29 -0400247 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 Marinasb69ec422012-10-08 16:28:11 -0700452config HAVE_DEBUG_KMEMLEAK
453 bool
454
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100455config DEBUG_KMEMLEAK
456 bool "Kernel memory leak detector"
Kees Cook525c1f92013-01-16 18:54:16 -0800457 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
Catalin Marinas79e0d9b2011-04-27 17:06:19 +0100458 select DEBUG_FS
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100459 select STACKTRACE if STACKTRACE_SUPPORT
460 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800461 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100462 help
463 Say Y here if you want to enable the memory leak
464 detector. The memory allocation/freeing is traced in a way
465 similar to the Boehm's conservative garbage collector, the
466 difference being that the orphan objects are not freed but
467 only shown in /sys/kernel/debug/kmemleak. Enabling this
468 feature will introduce an overhead to memory
469 allocations. See Documentation/kmemleak.txt for more
470 details.
471
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100472 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
473 of finding leaks due to the slab objects poisoning.
474
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100475 In order to access the kmemleak file, debugfs needs to be
476 mounted (usually at /sys/kernel/debug).
477
Catalin Marinasa9d90582009-06-25 10:16:11 +0100478config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
479 int "Maximum kmemleak early log entries"
480 depends on DEBUG_KMEMLEAK
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200481 range 200 40000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100482 default 400
483 help
484 Kmemleak must track all the memory allocations to avoid
485 reporting false positives. Since memory may be allocated or
486 freed before kmemleak is initialised, an early log buffer is
487 used to store these actions. If kmemleak reports "early log
488 buffer exceeded", please increase this value.
489
Catalin Marinas0822ee42009-06-11 13:24:14 +0100490config DEBUG_KMEMLEAK_TEST
491 tristate "Simple test for the kernel memory leak detector"
Daniel Baluta97182692011-04-04 15:06:44 -0700492 depends on DEBUG_KMEMLEAK && m
Catalin Marinas0822ee42009-06-11 13:24:14 +0100493 help
Daniel Baluta97182692011-04-04 15:06:44 -0700494 This option enables a module that explicitly leaks memory.
Catalin Marinas0822ee42009-06-11 13:24:14 +0100495
496 If unsure, say N.
497
Jason Baronab0155a2010-07-19 11:54:17 +0100498config DEBUG_KMEMLEAK_DEFAULT_OFF
499 bool "Default kmemleak to off"
500 depends on DEBUG_KMEMLEAK
501 help
502 Say Y here to disable kmemleak by default. It can then be enabled
503 on the command line via kmemleak=on.
504
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505config DEBUG_PREEMPT
506 bool "Debug preemptible kernel"
Kumar Gala01deab92009-10-16 07:21:39 +0000507 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 default y
509 help
510 If you say Y here then the kernel will use a debug variant of the
511 commonly used smp_processor_id() function and will print warnings
512 if kernel code uses it in a preemption-unsafe way. Also, the kernel
513 will detect preemption count underflows.
514
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700515config DEBUG_RT_MUTEXES
516 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700517 depends on DEBUG_KERNEL && RT_MUTEXES
518 help
519 This allows rt mutex semantics violations and rt mutex related
520 deadlocks (lockups) to be detected and reported automatically.
521
522config DEBUG_PI_LIST
523 bool
524 default y
525 depends on DEBUG_RT_MUTEXES
526
Thomas Gleixner61a87122006-06-27 02:54:56 -0700527config RT_MUTEX_TESTER
528 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700529 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700530 help
531 This option enables a rt-mutex tester.
532
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700534 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +0530536 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 help
538 Say Y here and build SMP to catch missing spinlock initialization
539 and certain other kinds of spinlock errors commonly made. This is
540 best used in conjunction with the NMI watchdog so that spinlock
541 deadlocks are also debuggable.
542
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700543config DEBUG_MUTEXES
544 bool "Mutex debugging: basic checks"
545 depends on DEBUG_KERNEL
546 help
547 This feature allows mutex semantics violations to be detected and
548 reported.
549
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700550config DEBUG_LOCK_ALLOC
551 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700552 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700553 select DEBUG_SPINLOCK
554 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700555 select LOCKDEP
556 help
557 This feature will check whether any held lock (spinlock, rwlock,
558 mutex or rwsem) is incorrectly freed by the kernel, via any of the
559 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
560 vfree(), etc.), whether a live lock is incorrectly reinitialized via
561 spin_lock_init()/mutex_init()/etc., or whether there is any lock
562 held during task exit.
563
564config PROVE_LOCKING
565 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700566 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700567 select LOCKDEP
568 select DEBUG_SPINLOCK
569 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700570 select DEBUG_LOCK_ALLOC
Steven Rostedt46b93b72010-08-31 16:35:20 -0400571 select TRACE_IRQFLAGS
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700572 default n
573 help
574 This feature enables the kernel to prove that all locking
575 that occurs in the kernel runtime is mathematically
576 correct: that under no circumstance could an arbitrary (and
577 not yet triggered) combination of observed locking
578 sequences (on an arbitrary number of CPUs, running an
579 arbitrary number of tasks and interrupt contexts) cause a
580 deadlock.
581
582 In short, this feature enables the kernel to report locking
583 related deadlocks before they actually occur.
584
585 The proof does not depend on how hard and complex a
586 deadlock scenario would be to trigger: how many
587 participant CPUs, tasks and irq-contexts would be needed
588 for it to trigger. The proof also does not depend on
589 timing: if a race and a resulting deadlock is possible
590 theoretically (no matter how unlikely the race scenario
591 is), it will be proven so and will immediately be
592 reported by the kernel (once the event is observed that
593 makes the deadlock theoretically possible).
594
595 If a deadlock is impossible (i.e. the locking rules, as
596 observed by the kernel, are mathematically correct), the
597 kernel reports nothing.
598
599 NOTE: this feature can also be enabled for rwlocks, mutexes
600 and rwsems - in which case all dependencies between these
601 different locking variants are observed and mapped too, and
602 the proof of observed correctness is also maintained for an
603 arbitrary combination of these separate locking variants.
604
605 For more details, see Documentation/lockdep-design.txt.
606
607config LOCKDEP
608 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700609 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700610 select STACKTRACE
Michal Simek79aac882010-05-25 11:33:26 +0200611 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700612 select KALLSYMS
613 select KALLSYMS_ALL
614
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700615config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700616 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700617 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
618 select LOCKDEP
619 select DEBUG_SPINLOCK
620 select DEBUG_MUTEXES
621 select DEBUG_LOCK_ALLOC
622 default n
623 help
624 This feature enables tracking lock contention points
625
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700626 For more details, see Documentation/lockstat.txt
627
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +0100628 This also enables lock events required by "perf lock",
629 subcommand of perf.
630 If you want to use "perf lock", you also need to turn on
631 CONFIG_EVENT_TRACING.
Hitoshi Mitake84c6f882010-02-04 16:08:15 +0900632
633 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +0100634 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
Hitoshi Mitake84c6f882010-02-04 16:08:15 +0900635
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700636config DEBUG_LOCKDEP
637 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700638 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700639 help
640 If you say Y here, the lock dependency engine will do
641 additional runtime checks to debug itself, at the price
642 of more runtime overhead.
643
644config TRACE_IRQFLAGS
645 bool
Steven Rostedt46b93b72010-08-31 16:35:20 -0400646 help
647 Enables hooks to interrupt enabling and disabling for
648 either tracing or lock debugging.
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700649
Frederic Weisbeckerd902db12011-06-08 19:31:56 +0200650config DEBUG_ATOMIC_SLEEP
651 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +0200652 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 depends on DEBUG_KERNEL
654 help
655 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +0200656 noisy if they are called inside atomic sections: when a spinlock is
657 held, inside an rcu read side critical section, inside preempt disabled
658 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700660config DEBUG_LOCKING_API_SELFTESTS
661 bool "Locking API boot-time self-tests"
662 depends on DEBUG_KERNEL
663 help
664 Say Y here if you want the kernel to run a short self-test during
665 bootup. The self-test checks whether common types of locking bugs
666 are detected by debugging mechanisms or not. (if you disable
667 lock debugging then those bugs wont be detected of course.)
668 The following locking APIs are covered: spinlocks, rwlocks,
669 mutexes and rwsems.
670
Ingo Molnar8637c092006-07-03 00:24:38 -0700671config STACKTRACE
672 bool
673 depends on STACKTRACE_SUPPORT
674
Stephen Boyd5ca43f62011-05-24 17:13:36 -0700675config DEBUG_STACK_USAGE
676 bool "Stack utilization instrumentation"
James Hogan79f83c02012-12-05 11:34:13 +0000677 depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG
Stephen Boyd5ca43f62011-05-24 17:13:36 -0700678 help
679 Enables the display of the minimum amount of free stack which each
680 task has ever had available in the sysrq-T and sysrq-P debug output.
681
682 This option will slow down process creation somewhat.
683
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684config DEBUG_KOBJECT
685 bool "kobject debugging"
686 depends on DEBUG_KERNEL
687 help
688 If you say Y here, some extra kobject debugging messages will be sent
689 to the syslog.
690
691config DEBUG_HIGHMEM
692 bool "Highmem debugging"
693 depends on DEBUG_KERNEL && HIGHMEM
694 help
695 This options enables addition error checking for high memory systems.
696 Disable for production systems.
697
Catalin Marinas9b2a60c2012-10-08 16:28:13 -0700698config HAVE_DEBUG_BUGVERBOSE
699 bool
700
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701config DEBUG_BUGVERBOSE
David Rientjes6a108a12011-01-20 14:44:16 -0800702 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
Catalin Marinas9b2a60c2012-10-08 16:28:13 -0700703 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
Alexey Dobriyan8420e7e2009-12-14 18:00:25 -0800704 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 help
706 Say Y here to make BUG() panics output the file name and line number
707 of the BUG call as well as the EIP and oops trace. This aids
708 debugging but costs about 70-100K of memory.
709
710config DEBUG_INFO
711 bool "Compile the kernel with debug info"
712 depends on DEBUG_KERNEL
713 help
714 If you say Y here the resulting kernel image will include
715 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600716 This adds debug symbols to the kernel and modules (gcc -g), and
717 is needed if you intend to use kernel crashdump or binary object
718 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 Say Y here only if you plan to debug the kernel.
720
721 If unsure, say N.
722
Andi Kleend6f4ceb2010-07-14 15:43:52 +0200723config DEBUG_INFO_REDUCED
724 bool "Reduce debugging information"
725 depends on DEBUG_INFO
726 help
727 If you say Y here gcc is instructed to generate less debugging
728 information for structure types. This means that tools that
729 need full debugging information (like kgdb or systemtap) won't
730 be happy. But if you merely need debugging information to
731 resolve line numbers there is no loss. Advantage is that
732 build directory object sizes shrink dramatically over a full
733 DEBUG_INFO build and compile times are reduced too.
734 Only works with newer gcc versions.
735
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800736config DEBUG_VM
737 bool "Debug VM"
738 depends on DEBUG_KERNEL
739 help
Nick Piggin13e74442006-01-06 00:10:58 -0800740 Enable this to turn on extended checks in the virtual-memory system
741 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800742
743 If unsure, say N.
744
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700745config DEBUG_VM_RB
746 bool "Debug VM red-black trees"
747 depends on DEBUG_VM
748 help
749 Enable this to turn on more extended checks in the virtual-memory
750 system that may impact performance.
751
752 If unsure, say N.
753
Jiri Slaby59ea7462008-06-12 13:56:40 +0200754config DEBUG_VIRTUAL
755 bool "Debug VM translations"
756 depends on DEBUG_KERNEL && X86
757 help
758 Enable some costly sanity checks in virtual to page code. This can
759 catch mistakes with virt_to_page() and friends.
760
761 If unsure, say N.
762
David Howells8feae132009-01-08 12:04:47 +0000763config DEBUG_NOMMU_REGIONS
764 bool "Debug the global anon/private NOMMU mapping region tree"
765 depends on DEBUG_KERNEL && !MMU
766 help
767 This option causes the global tree of anonymous and private mapping
768 regions to be regularly checked for invalid topology.
769
Dave Hansenad775f52008-02-15 14:38:01 -0800770config DEBUG_WRITECOUNT
771 bool "Debug filesystem writers count"
772 depends on DEBUG_KERNEL
773 help
774 Enable this to catch wrong use of the writers count in struct
775 vfsmount. This will increase the size of each file struct by
776 32 bits.
777
778 If unsure, say N.
779
Mel Gorman6b74ab92008-07-23 21:26:49 -0700780config DEBUG_MEMORY_INIT
David Rientjes6a108a12011-01-20 14:44:16 -0800781 bool "Debug memory initialisation" if EXPERT
782 default !EXPERT
Mel Gorman6b74ab92008-07-23 21:26:49 -0700783 help
784 Enable this for additional checks during memory initialisation.
785 The sanity checks verify aspects of the VM such as the memory model
786 and other information provided by the architecture. Verbose
787 information will be printed at KERN_DEBUG loglevel depending
788 on the mminit_loglevel= command-line option.
789
790 If unsure, say Y
791
Dave Jones199a9af2006-09-29 01:59:00 -0700792config DEBUG_LIST
793 bool "Debug linked list manipulation"
794 depends on DEBUG_KERNEL
795 help
796 Enable this to turn on extended checks in the linked-list
797 walking routines.
798
799 If unsure, say N.
800
Artem Bityutskiy6d411e62010-10-26 14:23:05 -0700801config TEST_LIST_SORT
802 bool "Linked list sorting test"
803 depends on DEBUG_KERNEL
804 help
805 Enable this to turn on 'list_sort()' function test. This test is
806 executed only once during system boot, so affects only boot time.
807
808 If unsure, say N.
809
Jens Axboed6ec0842007-10-22 20:01:06 +0200810config DEBUG_SG
811 bool "Debug SG table operations"
812 depends on DEBUG_KERNEL
813 help
814 Enable this to turn on checks on scatter-gather tables. This can
815 help find problems with drivers that do not properly initialize
816 their sg tables.
817
818 If unsure, say N.
819
Arjan van de Ven1b2439d2008-08-15 15:29:38 -0700820config DEBUG_NOTIFIERS
821 bool "Debug notifier call chains"
822 depends on DEBUG_KERNEL
823 help
824 Enable this to turn on sanity checking for notifier call chains.
825 This is most useful for kernel developers to make sure that
826 modules properly unregister themselves from notifier chains.
827 This is a relatively cheap check but if you care about maximum
828 performance, say N.
829
David Howellse0e81732009-09-02 09:13:40 +0100830config DEBUG_CREDENTIALS
831 bool "Debug credential management"
832 depends on DEBUG_KERNEL
833 help
834 Enable this to turn on some debug checking for credential
835 management. The additional code keeps track of the number of
836 pointers from task_structs to any given cred struct, and checks to
837 see that this number never exceeds the usage count of the cred
838 struct.
839
840 Furthermore, if SELinux is enabled, this also checks that the
841 security pointer in the cred struct is never seen to be invalid.
842
843 If unsure, say N.
844
Jeff Mahoney64dec402009-01-16 13:23:35 -0500845#
846# Select this config option from the architecture Kconfig, if it
Justin P. Mattock52288b62011-08-21 20:02:13 -0700847# is preferred to always offer frame pointers as a config
Jeff Mahoney64dec402009-01-16 13:23:35 -0500848# option on the architecture (regardless of KERNEL_DEBUG):
849#
850config ARCH_WANT_FRAME_POINTERS
851 bool
852 help
853
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854config FRAME_POINTER
855 bool "Compile the kernel with frame pointers"
David Howellsb920de12008-02-08 04:19:31 -0800856 depends on DEBUG_KERNEL && \
Geert Uytterhoeven73020412011-01-22 22:35:38 +0100857 (CRIS || M68K || FRV || UML || \
James Hogan79f83c02012-12-05 11:34:13 +0000858 AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \
Ingo Molnarda4276b2009-01-07 11:05:10 +0100859 ARCH_WANT_FRAME_POINTERS
860 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 help
Ingo Molnarda4276b2009-01-07 11:05:10 +0100862 If you say Y here the resulting kernel image will be slightly
863 larger and slower, but it gives very useful debugging information
864 in case of kernel bugs. (precise oopses/stacktraces/warnings)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700866config BOOT_PRINTK_DELAY
867 bool "Delay each boot printk message by N milliseconds"
868 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
869 help
870 This build option allows you to read kernel boot messages
871 by inserting a short delay after each one. The delay is
872 specified in milliseconds on the kernel command line,
873 using "boot_delay=N".
874
875 It is likely that you would also need to use "lpj=M" to preset
876 the "loops per jiffie" value.
877 See a previous boot log for the "lpj" value to use for your
878 system, and then set "lpj=M" before setting "boot_delay=N".
879 NOTE: Using this option may adversely affect SMP systems.
880 I.e., processors other than the first one may not boot up.
Anton Blanchard8edbb832011-07-05 13:32:40 +1000881 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700882 what it believes to be lockup conditions.
883
Dave Hansen2f03e3c2013-01-07 08:19:23 -0800884menu "RCU Debugging"
885
886config PROVE_RCU
887 bool "RCU debugging: prove RCU correctness"
888 depends on PROVE_LOCKING
889 default n
890 help
891 This feature enables lockdep extensions that check for correct
892 use of RCU APIs. This is currently under development. Say Y
893 if you want to debug RCU usage or help work on the PROVE_RCU
894 feature.
895
896 Say N if you are unsure.
897
898config PROVE_RCU_REPEATEDLY
899 bool "RCU debugging: don't disable PROVE_RCU on first splat"
900 depends on PROVE_RCU
901 default n
902 help
903 By itself, PROVE_RCU will disable checking upon issuing the
904 first warning (or "splat"). This feature prevents such
905 disabling, allowing multiple RCU-lockdep warnings to be printed
906 on a single reboot.
907
908 Say Y to allow multiple RCU-lockdep warnings per boot.
909
910 Say N if you are unsure.
911
912config PROVE_RCU_DELAY
913 bool "RCU debugging: preemptible RCU race provocation"
914 depends on DEBUG_KERNEL && PREEMPT_RCU
915 default n
916 help
917 There is a class of races that involve an unlikely preemption
918 of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
919 been set to INT_MIN. This feature inserts a delay at that
920 point to increase the probability of these races.
921
922 Say Y to increase probability of preemption of __rcu_read_unlock().
923
924 Say N if you are unsure.
925
926config SPARSE_RCU_POINTER
927 bool "RCU debugging: sparse-based checks for pointer usage"
928 default n
929 help
930 This feature enables the __rcu sparse annotation for
931 RCU-protected pointers. This annotation will cause sparse
932 to flag any non-RCU used of annotated pointers. This can be
933 helpful when debugging RCU usage. Please note that this feature
934 is not intended to enforce code cleanliness; it is instead merely
935 a debugging aid.
936
937 Say Y to make sparse flag questionable use of RCU-protected pointers
938
939 Say N if you are unsure.
940
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800941config RCU_TORTURE_TEST
942 tristate "torture tests for RCU"
943 depends on DEBUG_KERNEL
944 default n
945 help
946 This option provides a kernel module that runs torture tests
947 on the RCU infrastructure. The kernel module may be built
948 after the fact on the running kernel to be tested, if desired.
949
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700950 Say Y here if you want RCU torture tests to be built into
951 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800952 Say M if you want the RCU torture tests to build as a module.
953 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700954
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700955config RCU_TORTURE_TEST_RUNNABLE
956 bool "torture tests for RCU runnable by default"
957 depends on RCU_TORTURE_TEST = y
958 default n
959 help
960 This option provides a way to build the RCU torture tests
961 directly into the kernel without them starting up at boot
962 time. You can use /proc/sys/kernel/rcutorture_runnable
963 to manually override this setting. This /proc file is
964 available only when the RCU torture tests have been built
965 into the kernel.
966
967 Say Y here if you want the RCU torture tests to start during
968 boot (you probably don't).
969 Say N here if you want the RCU torture tests to start only
970 after being manually enabled via /proc.
971
Paul E. McKenneyb1637602010-06-02 16:21:38 -0700972config RCU_CPU_STALL_TIMEOUT
973 int "RCU CPU stall timeout in seconds"
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -0700974 depends on RCU_STALL_COMMON
Paul E. McKenneyb1637602010-06-02 16:21:38 -0700975 range 3 300
Paul E. McKenneyc8960542012-10-25 17:59:23 -0700976 default 21
Paul E. McKenneyb1637602010-06-02 16:21:38 -0700977 help
978 If a given RCU grace period extends more than the specified
979 number of seconds, a CPU stall warning is printed. If the
980 RCU grace period persists, additional CPU stall warnings are
981 printed at more widely spaced intervals.
982
Paul E. McKenney1ed509a2010-02-22 17:05:05 -0800983config RCU_CPU_STALL_VERBOSE
984 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
Paul E. McKenneya00e0d712011-02-08 17:14:39 -0800985 depends on TREE_PREEMPT_RCU
Paul E. McKenney55ec9362010-04-13 12:22:33 -0700986 default y
Paul E. McKenney1ed509a2010-02-22 17:05:05 -0800987 help
988 This option causes RCU to printk detailed per-task information
989 for any tasks that are stalling the current RCU grace period.
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100990
991 Say N if you are unsure.
992
Paul E. McKenney1ed509a2010-02-22 17:05:05 -0800993 Say Y if you want to enable such checks.
994
Paul E. McKenneya858af22012-01-16 13:29:10 -0800995config RCU_CPU_STALL_INFO
996 bool "Print additional diagnostics on RCU CPU stall"
997 depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
998 default n
999 help
1000 For each stalled CPU that is aware of the current RCU grace
1001 period, print out additional per-CPU diagnostic information
1002 regarding scheduling-clock ticks, idle state, and,
1003 for RCU_FAST_NO_HZ kernels, idle-entry state.
1004
1005 Say N if you are unsure.
1006
1007 Say Y if you want to enable such diagnostics.
1008
Paul E. McKenney5c8806a2012-01-06 15:10:44 -08001009config RCU_TRACE
1010 bool "Enable tracing for RCU"
1011 depends on DEBUG_KERNEL
Paul E. McKenney52494532012-11-14 16:26:40 -08001012 select TRACE_CLOCK
Paul E. McKenney5c8806a2012-01-06 15:10:44 -08001013 help
1014 This option provides tracing in RCU which presents stats
1015 in debugfs for debugging RCU implementation.
1016
1017 Say Y here if you want to enable RCU tracing
1018 Say N if you are unsure.
1019
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001020endmenu # "RCU Debugging"
1021
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +01001022config KPROBES_SANITY_TEST
1023 bool "Kprobes sanity tests"
1024 depends on DEBUG_KERNEL
1025 depends on KPROBES
1026 default n
1027 help
1028 This option provides for testing basic kprobes functionality on
1029 boot. A sample kprobe, jprobe and kretprobe are inserted and
1030 verified for functionality.
1031
1032 Say N if you are unsure.
1033
Arjan van de Ven6dab2772008-01-30 13:33:08 +01001034config BACKTRACE_SELF_TEST
1035 tristate "Self test for the backtrace code"
1036 depends on DEBUG_KERNEL
1037 default n
1038 help
1039 This option provides a kernel module that can be used to test
1040 the kernel stack backtrace code. This option is not useful
1041 for distributions or general kernels, but only for kernel
1042 developers working on architecture code.
1043
Vegard Nossumad118c52008-06-27 18:04:48 +02001044 Note that if you want to also test saved backtraces, you will
1045 have to enable STACKTRACE as well.
1046
Arjan van de Ven6dab2772008-01-30 13:33:08 +01001047 Say N if you are unsure.
1048
Tejun Heo870d6652008-08-25 19:47:25 +09001049config DEBUG_BLOCK_EXT_DEVT
1050 bool "Force extended block device numbers and spread them"
1051 depends on DEBUG_KERNEL
1052 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +02001053 default n
Tejun Heo870d6652008-08-25 19:47:25 +09001054 help
Tejun Heo0e11e342008-10-13 10:46:01 +02001055 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1056 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1057 YOU ARE DOING. Distros, please enable this and fix whatever
1058 is broken.
1059
Tejun Heo870d6652008-08-25 19:47:25 +09001060 Conventionally, block device numbers are allocated from
1061 predetermined contiguous area. However, extended block area
1062 may introduce non-contiguous block device numbers. This
1063 option forces most block device numbers to be allocated from
1064 the extended space and spreads them to discover kernel or
1065 userland code paths which assume predetermined contiguous
1066 device number allocation.
1067
Tejun Heo55dc7db2008-09-01 13:44:35 +02001068 Note that turning on this debug option shuffles all the
1069 device numbers for all IDE and SCSI devices including libata
1070 ones, so root partition specified using device number
1071 directly (via rdev or root=MAJ:MIN) won't work anymore.
1072 Textual device names (root=/dev/sdXn) will continue to work.
1073
Tejun Heo870d6652008-08-25 19:47:25 +09001074 Say N if you are unsure.
1075
Tejun Heo7c756e62009-06-24 15:13:50 +09001076config DEBUG_FORCE_WEAK_PER_CPU
1077 bool "Force weak per-cpu definitions"
1078 depends on DEBUG_KERNEL
1079 help
1080 s390 and alpha require percpu variables in modules to be
1081 defined weak to work around addressing range issue which
1082 puts the following two restrictions on percpu variable
1083 definitions.
1084
1085 1. percpu symbols must be unique whether static or not
1086 2. percpu variables can't be defined inside a function
1087
1088 To ensure that generic code follows the above rules, this
1089 option forces all percpu variables to be defined as weak.
1090
Stephen Boyd44ec7ab2011-05-24 17:13:32 -07001091config DEBUG_PER_CPU_MAPS
1092 bool "Debug access to per_cpu maps"
1093 depends on DEBUG_KERNEL
1094 depends on SMP
1095 help
1096 Say Y to verify that the per_cpu map being accessed has
1097 been set up. This adds a fair amount of code to kernel memory
1098 and decreases performance.
1099
1100 Say N if unsure.
1101
Ankita Garg8bb31b92006-10-02 02:17:36 -07001102config LKDTM
1103 tristate "Linux Kernel Dump Test Tool Module"
Simon Kagstrom0347af42010-03-05 13:42:49 -08001104 depends on DEBUG_FS
Chris Snookfddd9cf2008-02-23 15:23:26 -08001105 depends on BLOCK
Ankita Garg8bb31b92006-10-02 02:17:36 -07001106 default n
1107 help
1108 This module enables testing of the different dumping mechanisms by
1109 inducing system failures at predefined crash points.
1110 If you don't need it: say N
1111 Choose M here to compile this code as a module. The module will be
1112 called lkdtm.
1113
1114 Documentation on how to use the module can be found in
Simon Kagstrom0347af42010-03-05 13:42:49 -08001115 Documentation/fault-injection/provoke-crashes.txt
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001116
Akinobu Mita8d438282012-07-30 14:43:02 -07001117config NOTIFIER_ERROR_INJECTION
1118 tristate "Notifier error injection"
1119 depends on DEBUG_KERNEL
1120 select DEBUG_FS
1121 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001122 This option provides the ability to inject artificial errors to
Akinobu Mita8d438282012-07-30 14:43:02 -07001123 specified notifier chain callbacks. It is useful to test the error
1124 handling of notifier call chain failures.
1125
1126 Say N if unsure.
1127
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001128config CPU_NOTIFIER_ERROR_INJECT
1129 tristate "CPU notifier error injection module"
Akinobu Mitaf5a9f522012-07-30 14:43:03 -07001130 depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001131 help
1132 This option provides a kernel module that can be used to test
Masanari Iidae41e85c2012-11-30 16:44:39 +09001133 the error handling of the cpu notifiers by injecting artificial
Akinobu Mitaf5a9f522012-07-30 14:43:03 -07001134 errors to CPU notifier chain callbacks. It is controlled through
1135 debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu
1136
1137 If the notifier call chain should be failed with some events
1138 notified, write the error code to "actions/<notifier event>/error".
1139
1140 Example: Inject CPU offline error (-1 == -EPERM)
1141
1142 # cd /sys/kernel/debug/notifier-error-inject/cpu
1143 # echo -1 > actions/CPU_DOWN_PREPARE/error
1144 # echo 0 > /sys/devices/system/cpu/cpu1/online
1145 bash: echo: write error: Operation not permitted
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001146
1147 To compile this code as a module, choose M here: the module will
1148 be called cpu-notifier-error-inject.
1149
1150 If unsure, say N.
1151
Akinobu Mita048b9c32012-07-30 14:43:07 -07001152config PM_NOTIFIER_ERROR_INJECT
1153 tristate "PM notifier error injection module"
1154 depends on PM && NOTIFIER_ERROR_INJECTION
1155 default m if PM_DEBUG
1156 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001157 This option provides the ability to inject artificial errors to
Akinobu Mita048b9c32012-07-30 14:43:07 -07001158 PM notifier chain callbacks. It is controlled through debugfs
1159 interface /sys/kernel/debug/notifier-error-inject/pm
1160
1161 If the notifier call chain should be failed with some events
1162 notified, write the error code to "actions/<notifier event>/error".
1163
1164 Example: Inject PM suspend error (-12 = -ENOMEM)
1165
1166 # cd /sys/kernel/debug/notifier-error-inject/pm/
1167 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1168 # echo mem > /sys/power/state
1169 bash: echo: write error: Cannot allocate memory
1170
1171 To compile this code as a module, choose M here: the module will
1172 be called pm-notifier-error-inject.
1173
1174 If unsure, say N.
1175
Akinobu Mita9579f5b2012-07-30 14:43:10 -07001176config MEMORY_NOTIFIER_ERROR_INJECT
1177 tristate "Memory hotplug notifier error injection module"
1178 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
1179 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001180 This option provides the ability to inject artificial errors to
Akinobu Mita9579f5b2012-07-30 14:43:10 -07001181 memory hotplug notifier chain callbacks. It is controlled through
1182 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
1183
1184 If the notifier call chain should be failed with some events
1185 notified, write the error code to "actions/<notifier event>/error".
1186
1187 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
1188
1189 # cd /sys/kernel/debug/notifier-error-inject/memory
1190 # echo -12 > actions/MEM_GOING_OFFLINE/error
1191 # echo offline > /sys/devices/system/memory/memoryXXX/state
1192 bash: echo: write error: Cannot allocate memory
1193
1194 To compile this code as a module, choose M here: the module will
1195 be called pSeries-reconfig-notifier-error-inject.
1196
1197 If unsure, say N.
1198
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001199config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1200 tristate "OF reconfig notifier error injection module"
1201 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001202 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001203 This option provides the ability to inject artificial errors to
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001204 OF reconfig notifier chain callbacks. It is controlled
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001205 through debugfs interface under
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001206 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001207
1208 If the notifier call chain should be failed with some events
1209 notified, write the error code to "actions/<notifier event>/error".
1210
1211 To compile this code as a module, choose M here: the module will
1212 be called memory-notifier-error-inject.
1213
1214 If unsure, say N.
1215
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001216config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001217 bool "Fault-injection framework"
1218 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001219 help
1220 Provide fault-injection framework.
1221 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001222
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001223config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001224 bool "Fault-injection capability for kmalloc"
1225 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001226 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001227 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001228 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001229
Akinobu Mita933e3122006-12-08 02:39:45 -08001230config FAIL_PAGE_ALLOC
1231 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001232 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001233 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001234 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001235
Akinobu Mitac17bb492006-12-08 02:39:46 -08001236config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001237 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001238 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001239 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001240 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001241
Jens Axboe581d4e22008-09-14 05:56:33 -07001242config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d014392010-07-21 16:05:53 +09001243 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001244 depends on FAULT_INJECTION && BLOCK
1245 help
1246 Provide fault-injection capability on end IO handling. This
1247 will make the block layer "forget" an interrupt as configured,
1248 thus exercising the error handling.
1249
1250 Only works with drivers that use the generic timeout handling,
1251 for others it wont do anything.
1252
Per Forlin1b676f72011-08-19 14:52:37 +02001253config FAIL_MMC_REQUEST
1254 bool "Fault-injection capability for MMC IO"
1255 select DEBUG_FS
1256 depends on FAULT_INJECTION && MMC
1257 help
1258 Provide fault-injection capability for MMC IO.
1259 This will make the mmc core return data errors. This is
1260 useful to test the error handling in the mmc block device
1261 and to test how the mmc host driver handles retries from
1262 the block device.
1263
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001264config FAULT_INJECTION_DEBUG_FS
1265 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001266 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001267 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001268 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -08001269
1270config FAULT_INJECTION_STACKTRACE_FILTER
1271 bool "stacktrace filter for fault-injection capabilities"
1272 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001273 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001274 select STACKTRACE
Arnd Bergmann89bace62011-06-10 14:12:21 +00001275 select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
Akinobu Mita1df49002007-02-20 13:57:56 -08001276 help
1277 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001278
Arjan van de Ven97455122008-01-25 21:08:34 +01001279config LATENCYTOP
1280 bool "Latency measuring infrastructure"
Randy Dunlap625fdca2010-08-12 12:31:21 -07001281 depends on HAVE_LATENCYTOP_SUPPORT
1282 depends on DEBUG_KERNEL
1283 depends on STACKTRACE_SUPPORT
1284 depends on PROC_FS
Arnd Bergmann89bace62011-06-10 14:12:21 +00001285 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
Arjan van de Ven97455122008-01-25 21:08:34 +01001286 select KALLSYMS
1287 select KALLSYMS_ALL
1288 select STACKTRACE
1289 select SCHEDSTATS
1290 select SCHED_DEBUG
Arjan van de Ven97455122008-01-25 21:08:34 +01001291 help
1292 Enable this option if you want to use the LatencyTOP tool
1293 to find out which userspace is blocking on what kernel operations.
1294
Akinobu Mita6a11f752009-03-31 15:23:17 -07001295source mm/Kconfig.debug
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001296source kernel/trace/Kconfig
1297
Michel Lespinasse910a7422012-10-08 16:30:39 -07001298config RBTREE_TEST
1299 tristate "Red-Black tree test"
1300 depends on m && DEBUG_KERNEL
1301 help
1302 A benchmark measuring the performance of the rbtree library.
1303 Also includes rbtree invariant checks.
1304
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001305config INTERVAL_TREE_TEST
1306 tristate "Interval tree test"
1307 depends on m && DEBUG_KERNEL
1308 help
1309 A benchmark measuring the performance of the interval tree library
1310
Bernhard Kaindlf212ec42008-01-30 13:34:11 +01001311config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +01001312 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +01001313 depends on PCI && X86
1314 help
1315 If you want to debug problems which hang or crash the kernel early
1316 on boot and the crashing machine has a FireWire port, you can use
1317 this feature to remotely access the memory of the crashed machine
1318 over FireWire. This employs remote DMA as part of the OHCI1394
1319 specification which is now the standard for FireWire controllers.
1320
1321 With remote DMA, you can monitor the printk buffer remotely using
1322 firescope and access all memory below 4GB using fireproxy from gdb.
1323 Even controlling a kernel debugger is possible using remote DMA.
1324
1325 Usage:
1326
1327 If ohci1394_dma=early is used as boot parameter, it will initialize
1328 all OHCI1394 controllers which are found in the PCI config space.
1329
1330 As all changes to the FireWire bus such as enabling and disabling
1331 devices cause a bus reset and thereby disable remote DMA for all
1332 devices, be sure to have the cable plugged and FireWire enabled on
1333 the debugging host before booting the debug target for debugging.
1334
1335 This code (~1k) is freed after boot. By then, the firewire stack
1336 in charge of the OHCI-1394 controllers should be used instead.
1337
1338 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +01001339
Stefan Richter080de8c2008-02-28 20:54:43 +01001340config FIREWIRE_OHCI_REMOTE_DMA
1341 bool "Remote debugging over FireWire with firewire-ohci"
1342 depends on FIREWIRE_OHCI
1343 help
1344 This option lets you use the FireWire bus for remote debugging
1345 with help of the firewire-ohci driver. It enables unfiltered
1346 remote DMA in firewire-ohci.
1347 See Documentation/debugging-via-ohci1394.txt for more information.
1348
1349 If unsure, say N.
1350
Randy Dunlap152de302009-02-20 15:38:47 -08001351config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -07001352 bool "Build targets in Documentation/ tree"
1353 depends on HEADERS_CHECK
1354 help
1355 This option attempts to build objects from the source files in the
1356 kernel Documentation/ tree.
1357
1358 Say N if you are unsure.
1359
Jason Barone9d376f2009-02-05 11:51:38 -05001360config DYNAMIC_DEBUG
Jason Baron86151fd2009-02-05 11:53:15 -05001361 bool "Enable dynamic printk() support"
Jason Baron346e15b2008-08-12 16:46:19 -04001362 default n
1363 depends on PRINTK
Jason Baron86151fd2009-02-05 11:53:15 -05001364 depends on DEBUG_FS
Jason Baron346e15b2008-08-12 16:46:19 -04001365 help
1366
1367 Compiles debug level messages into the kernel, which would not
1368 otherwise be available at runtime. These messages can then be
Jason Baron86151fd2009-02-05 11:53:15 -05001369 enabled/disabled based on various levels of scope - per source file,
1370 function, module, format string, and line number. This mechanism
Jim Cromie29e36c92012-04-27 14:30:41 -06001371 implicitly compiles in all pr_debug() and dev_dbg() calls, which
1372 enlarges the kernel text size by about 2%.
1373
1374 If a source file is compiled with DEBUG flag set, any
1375 pr_debug() calls in it are enabled by default, but can be
1376 disabled at runtime as below. Note that DEBUG flag is
1377 turned on by many CONFIG_*DEBUG* options.
Jason Baron346e15b2008-08-12 16:46:19 -04001378
1379 Usage:
1380
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001381 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
Jason Baron86151fd2009-02-05 11:53:15 -05001382 which is contained in the 'debugfs' filesystem. Thus, the debugfs
1383 filesystem must first be mounted before making use of this feature.
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001384 We refer the control file as: <debugfs>/dynamic_debug/control. This
Jason Baron86151fd2009-02-05 11:53:15 -05001385 file contains a list of the debug statements that can be enabled. The
1386 format for each line of the file is:
Jason Baron346e15b2008-08-12 16:46:19 -04001387
Jason Baron86151fd2009-02-05 11:53:15 -05001388 filename:lineno [module]function flags format
Jason Baron346e15b2008-08-12 16:46:19 -04001389
Jason Baron86151fd2009-02-05 11:53:15 -05001390 filename : source file of the debug statement
1391 lineno : line number of the debug statement
1392 module : module that contains the debug statement
1393 function : function that contains the debug statement
Jim Cromie29e36c92012-04-27 14:30:41 -06001394 flags : '=p' means the line is turned 'on' for printing
Jason Baron86151fd2009-02-05 11:53:15 -05001395 format : the format used for the debug statement
Jason Baron346e15b2008-08-12 16:46:19 -04001396
1397 From a live system:
1398
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001399 nullarbor:~ # cat <debugfs>/dynamic_debug/control
Jason Baron86151fd2009-02-05 11:53:15 -05001400 # filename:lineno [module]function flags format
Jim Cromie29e36c92012-04-27 14:30:41 -06001401 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
1402 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
1403 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
Jason Baron346e15b2008-08-12 16:46:19 -04001404
Jason Baron86151fd2009-02-05 11:53:15 -05001405 Example usage:
Jason Baron346e15b2008-08-12 16:46:19 -04001406
Jason Baron86151fd2009-02-05 11:53:15 -05001407 // enable the message at line 1603 of file svcsock.c
1408 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001409 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001410
Jason Baron86151fd2009-02-05 11:53:15 -05001411 // enable all the messages in file svcsock.c
1412 nullarbor:~ # echo -n 'file svcsock.c +p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001413 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001414
Jason Baron86151fd2009-02-05 11:53:15 -05001415 // enable all the messages in the NFS server module
1416 nullarbor:~ # echo -n 'module nfsd +p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001417 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001418
Jason Baron86151fd2009-02-05 11:53:15 -05001419 // enable all 12 messages in the function svc_process()
1420 nullarbor:~ # echo -n 'func svc_process +p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001421 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001422
Jason Baron86151fd2009-02-05 11:53:15 -05001423 // disable all 12 messages in the function svc_process()
1424 nullarbor:~ # echo -n 'func svc_process -p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001425 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001426
Jason Baron86151fd2009-02-05 11:53:15 -05001427 See Documentation/dynamic-debug-howto.txt for additional information.
Jason Baron346e15b2008-08-12 16:46:19 -04001428
Joerg Roedel5ee00bd2009-01-09 12:14:24 +01001429config DMA_API_DEBUG
1430 bool "Enable debugging of DMA-API usage"
1431 depends on HAVE_DMA_API_DEBUG
1432 help
1433 Enable this option to debug the use of the DMA API by device drivers.
1434 With this option you will be able to detect common bugs in device
1435 drivers like double-freeing of DMA mappings or freeing mappings that
1436 were never allocated.
1437 This option causes a performance degredation. Use only if you want
1438 to debug device drivers. If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -04001439
Luca Barbieri86a89382010-02-24 10:54:24 +01001440config ATOMIC64_SELFTEST
1441 bool "Perform an atomic64_t self-test at boot"
1442 help
1443 Enable this option to test the atomic64_t functions at boot.
1444
1445 If unsure, say N.
1446
Dan Williams400fb7f2010-10-07 15:25:04 -07001447config ASYNC_RAID6_TEST
1448 tristate "Self test for hardware accelerated raid6 recovery"
1449 depends on ASYNC_RAID6_RECOV
1450 select ASYNC_MEMCPY
1451 ---help---
1452 This is a one-shot self test that permutes through the
1453 recovery of all the possible two disk failure scenarios for a
1454 N-disk array. Recovery is performed with the asynchronous
1455 raid6 recovery routines, and will optionally use an offload
1456 engine if one is available.
1457
1458 If unsure, say N.
1459
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001460source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02001461
1462source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001463
1464source "lib/Kconfig.kmemcheck"
Alexey Dobriyan33ee3b22011-03-22 16:34:40 -07001465
1466config TEST_KSTRTOX
1467 tristate "Test kstrto*() family of functions at runtime"