blob: 122db3d323c88a338211bf3570e57f140deefc7a [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
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
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
246 bool "Panic on Oops" if EXPERT
247 default n
248 help
249 Say Y here to enable the kernel to panic when it oopses. This
250 has the same effect as setting oops=panic on the kernel command
251 line.
252
253 This feature is useful to ensure that the kernel does not do
254 anything erroneous after an oops which could result in data
255 corruption or other issues.
256
257 Say N if unsure.
258
259config PANIC_ON_OOPS_VALUE
260 int
261 range 0 1
262 default 0 if !PANIC_ON_OOPS
263 default 1 if PANIC_ON_OOPS
264
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800265config DETECT_HUNG_TASK
266 bool "Detect Hung Tasks"
267 depends on DEBUG_KERNEL
Anton Blanchard8edbb832011-07-05 13:32:40 +1000268 default LOCKUP_DETECTOR
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800269 help
270 Say Y here to enable the kernel to detect "hung tasks",
271 which are bugs that cause the task to be stuck in
272 uninterruptible "D" state indefinitiley.
273
274 When a hung task is detected, the kernel will print the
275 current stack trace (which you should report), but the
276 task will stay in uninterruptible state. If lockdep is
277 enabled then all held locks will also be reported. This
278 feature has negligible overhead.
279
Jeff Mahoneye11feaa2011-04-27 14:27:24 -0400280config DEFAULT_HUNG_TASK_TIMEOUT
281 int "Default timeout for hung task detection (in seconds)"
282 depends on DETECT_HUNG_TASK
283 default 120
284 help
285 This option controls the default timeout (in seconds) used
286 to determine when a task has become non-responsive and should
287 be considered hung.
288
Jiaju Zhangc51eaac2011-10-31 17:10:07 -0700289 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
290 sysctl or by writing a value to
291 /proc/sys/kernel/hung_task_timeout_secs.
Jeff Mahoneye11feaa2011-04-27 14:27:24 -0400292
293 A timeout of 0 disables the check. The default is two minutes.
294 Keeping the default should be fine in most cases.
295
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800296config BOOTPARAM_HUNG_TASK_PANIC
297 bool "Panic (Reboot) On Hung Tasks"
298 depends on DETECT_HUNG_TASK
299 help
300 Say Y here to enable the kernel to panic on "hung tasks",
301 which are bugs that cause the kernel to leave a task stuck
302 in uninterruptible "D" state.
303
304 The panic can be used in combination with panic_timeout,
305 to cause the system to reboot automatically after a
306 hung task has been detected. This feature is useful for
307 high-availability systems that have uptime guarantees and
308 where a hung tasks must be resolved ASAP.
309
310 Say N if unsure.
311
312config BOOTPARAM_HUNG_TASK_PANIC_VALUE
313 int
314 depends on DETECT_HUNG_TASK
315 range 0 1
316 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
317 default 1 if BOOTPARAM_HUNG_TASK_PANIC
318
Ingo Molnarb642b6d2007-07-09 18:52:00 +0200319config SCHED_DEBUG
320 bool "Collect scheduler debugging info"
321 depends on DEBUG_KERNEL && PROC_FS
322 default y
323 help
324 If you say Y here, the /proc/sched_debug file will be provided
325 that can help debug the scheduler. The runtime overhead of this
326 option is minimal.
327
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328config SCHEDSTATS
329 bool "Collect scheduler statistics"
330 depends on DEBUG_KERNEL && PROC_FS
331 help
332 If you say Y here, additional code will be inserted into the
333 scheduler and related routines to collect statistics about
334 scheduler behavior and provide them in /proc/schedstat. These
335 stats may be useful for both tuning and debugging the scheduler
336 If you aren't debugging the scheduler or trying to tune a specific
337 application, you can say N to avoid the very slight overhead
338 this adds.
339
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800340config TIMER_STATS
341 bool "Collect kernel timers statistics"
342 depends on DEBUG_KERNEL && PROC_FS
343 help
344 If you say Y here, additional code will be inserted into the
345 timer routines to collect statistics about kernel timers being
346 reprogrammed. The statistics can be read from /proc/timer_stats.
347 The statistics collection is started by writing 1 to /proc/timer_stats,
348 writing 0 stops it. This feature is useful to collect information
Ingo Molnarc1a834d2007-06-01 00:47:16 -0700349 about timer usage patterns in kernel and userspace. This feature
350 is lightweight if enabled in the kernel config but not activated
351 (it defaults to deactivated on bootup and will only be activated
352 if some application like powertop activates it explicitly).
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800353
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700354config DEBUG_OBJECTS
355 bool "Debug object operations"
356 depends on DEBUG_KERNEL
357 help
358 If you say Y here, additional code will be inserted into the
359 kernel to track the life time of various objects and validate
360 the operations on those objects.
361
362config DEBUG_OBJECTS_SELFTEST
363 bool "Debug objects selftest"
364 depends on DEBUG_OBJECTS
365 help
366 This enables the selftest of the object debug code.
367
368config DEBUG_OBJECTS_FREE
369 bool "Debug objects in freed memory"
370 depends on DEBUG_OBJECTS
371 help
372 This enables checks whether a k/v free operation frees an area
373 which contains an object which has not been deactivated
374 properly. This can make kmalloc/kfree-intensive workloads
375 much slower.
376
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700377config DEBUG_OBJECTS_TIMERS
378 bool "Debug timer objects"
379 depends on DEBUG_OBJECTS
380 help
381 If you say Y here, additional code will be inserted into the
382 timer routines to track the life time of timer objects and
383 validate the timer operations.
384
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900385config DEBUG_OBJECTS_WORK
386 bool "Debug work objects"
387 depends on DEBUG_OBJECTS
388 help
389 If you say Y here, additional code will be inserted into the
390 work queue routines to track the life time of work objects and
391 validate the work operations.
392
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400393config DEBUG_OBJECTS_RCU_HEAD
394 bool "Debug RCU callbacks objects"
Mathieu Desnoyersfc2ecf72011-02-23 09:42:14 -0800395 depends on DEBUG_OBJECTS
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400396 help
397 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
398
Tejun Heoe2852ae2010-10-26 14:23:05 -0700399config DEBUG_OBJECTS_PERCPU_COUNTER
400 bool "Debug percpu counter objects"
401 depends on DEBUG_OBJECTS
402 help
403 If you say Y here, additional code will be inserted into the
404 percpu counter routines to track the life time of percpu counter
405 objects and validate the percpu counter operations.
406
Ingo Molnar3ae70202008-11-26 10:02:00 +0100407config DEBUG_OBJECTS_ENABLE_DEFAULT
408 int "debug_objects bootup default value (0-1)"
409 range 0 1
410 default "1"
411 depends on DEBUG_OBJECTS
412 help
413 Debug objects boot parameter default value
414
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800416 bool "Debug slab memory allocations"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200417 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 help
419 Say Y here to have the kernel do limited verification on memory
420 allocation as well as poisoning memory on free to catch use of freed
421 memory. This can make kmalloc/kfree-intensive workloads much slower.
422
Al Viro871751e2006-03-25 03:06:39 -0800423config DEBUG_SLAB_LEAK
424 bool "Memory leak debugging"
425 depends on DEBUG_SLAB
426
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700427config SLUB_DEBUG_ON
428 bool "SLUB debugging on by default"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200429 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700430 default n
431 help
432 Boot with debugging on by default. SLUB boots by default with
433 the runtime debug capabilities switched off. Enabling this is
434 equivalent to specifying the "slub_debug" parameter on boot.
435 There is no support for more fine grained debug control like
436 possible with slub_debug=xxx. SLUB debugging may be switched
437 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
438 "slub_debug=-".
439
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800440config SLUB_STATS
441 default n
442 bool "Enable SLUB performance statistics"
Christoph Lameterab4d5ed2010-10-05 13:57:26 -0500443 depends on SLUB && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800444 help
445 SLUB statistics are useful to debug SLUBs allocation behavior in
446 order find ways to optimize the allocator. This should never be
447 enabled for production use since keeping statistics slows down
448 the allocator by a few percentage points. The slabinfo command
449 supports the determination of the most active slabs to figure
450 out which slabs are relevant to a particular load.
451 Try running: slabinfo -DA
452
Catalin Marinasb69ec422012-10-08 16:28:11 -0700453config HAVE_DEBUG_KMEMLEAK
454 bool
455
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100456config DEBUG_KMEMLEAK
457 bool "Kernel memory leak detector"
Catalin Marinasb69ec422012-10-08 16:28:11 -0700458 depends on DEBUG_KERNEL && EXPERIMENTAL && HAVE_DEBUG_KMEMLEAK
Catalin Marinas79e0d9b2011-04-27 17:06:19 +0100459 select DEBUG_FS
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100460 select STACKTRACE if STACKTRACE_SUPPORT
461 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800462 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100463 help
464 Say Y here if you want to enable the memory leak
465 detector. The memory allocation/freeing is traced in a way
466 similar to the Boehm's conservative garbage collector, the
467 difference being that the orphan objects are not freed but
468 only shown in /sys/kernel/debug/kmemleak. Enabling this
469 feature will introduce an overhead to memory
470 allocations. See Documentation/kmemleak.txt for more
471 details.
472
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100473 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
474 of finding leaks due to the slab objects poisoning.
475
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100476 In order to access the kmemleak file, debugfs needs to be
477 mounted (usually at /sys/kernel/debug).
478
Catalin Marinasa9d90582009-06-25 10:16:11 +0100479config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
480 int "Maximum kmemleak early log entries"
481 depends on DEBUG_KMEMLEAK
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200482 range 200 40000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100483 default 400
484 help
485 Kmemleak must track all the memory allocations to avoid
486 reporting false positives. Since memory may be allocated or
487 freed before kmemleak is initialised, an early log buffer is
488 used to store these actions. If kmemleak reports "early log
489 buffer exceeded", please increase this value.
490
Catalin Marinas0822ee42009-06-11 13:24:14 +0100491config DEBUG_KMEMLEAK_TEST
492 tristate "Simple test for the kernel memory leak detector"
Daniel Baluta97182692011-04-04 15:06:44 -0700493 depends on DEBUG_KMEMLEAK && m
Catalin Marinas0822ee42009-06-11 13:24:14 +0100494 help
Daniel Baluta97182692011-04-04 15:06:44 -0700495 This option enables a module that explicitly leaks memory.
Catalin Marinas0822ee42009-06-11 13:24:14 +0100496
497 If unsure, say N.
498
Jason Baronab0155a2010-07-19 11:54:17 +0100499config DEBUG_KMEMLEAK_DEFAULT_OFF
500 bool "Default kmemleak to off"
501 depends on DEBUG_KMEMLEAK
502 help
503 Say Y here to disable kmemleak by default. It can then be enabled
504 on the command line via kmemleak=on.
505
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506config DEBUG_PREEMPT
507 bool "Debug preemptible kernel"
Kumar Gala01deab92009-10-16 07:21:39 +0000508 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 default y
510 help
511 If you say Y here then the kernel will use a debug variant of the
512 commonly used smp_processor_id() function and will print warnings
513 if kernel code uses it in a preemption-unsafe way. Also, the kernel
514 will detect preemption count underflows.
515
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700516config DEBUG_RT_MUTEXES
517 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700518 depends on DEBUG_KERNEL && RT_MUTEXES
519 help
520 This allows rt mutex semantics violations and rt mutex related
521 deadlocks (lockups) to be detected and reported automatically.
522
523config DEBUG_PI_LIST
524 bool
525 default y
526 depends on DEBUG_RT_MUTEXES
527
Thomas Gleixner61a87122006-06-27 02:54:56 -0700528config RT_MUTEX_TESTER
529 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700530 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700531 help
532 This option enables a rt-mutex tester.
533
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700535 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +0530537 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 help
539 Say Y here and build SMP to catch missing spinlock initialization
540 and certain other kinds of spinlock errors commonly made. This is
541 best used in conjunction with the NMI watchdog so that spinlock
542 deadlocks are also debuggable.
543
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700544config DEBUG_MUTEXES
545 bool "Mutex debugging: basic checks"
546 depends on DEBUG_KERNEL
547 help
548 This feature allows mutex semantics violations to be detected and
549 reported.
550
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700551config DEBUG_LOCK_ALLOC
552 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700553 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700554 select DEBUG_SPINLOCK
555 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700556 select LOCKDEP
557 help
558 This feature will check whether any held lock (spinlock, rwlock,
559 mutex or rwsem) is incorrectly freed by the kernel, via any of the
560 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
561 vfree(), etc.), whether a live lock is incorrectly reinitialized via
562 spin_lock_init()/mutex_init()/etc., or whether there is any lock
563 held during task exit.
564
565config PROVE_LOCKING
566 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700567 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700568 select LOCKDEP
569 select DEBUG_SPINLOCK
570 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700571 select DEBUG_LOCK_ALLOC
Steven Rostedt46b93b72010-08-31 16:35:20 -0400572 select TRACE_IRQFLAGS
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700573 default n
574 help
575 This feature enables the kernel to prove that all locking
576 that occurs in the kernel runtime is mathematically
577 correct: that under no circumstance could an arbitrary (and
578 not yet triggered) combination of observed locking
579 sequences (on an arbitrary number of CPUs, running an
580 arbitrary number of tasks and interrupt contexts) cause a
581 deadlock.
582
583 In short, this feature enables the kernel to report locking
584 related deadlocks before they actually occur.
585
586 The proof does not depend on how hard and complex a
587 deadlock scenario would be to trigger: how many
588 participant CPUs, tasks and irq-contexts would be needed
589 for it to trigger. The proof also does not depend on
590 timing: if a race and a resulting deadlock is possible
591 theoretically (no matter how unlikely the race scenario
592 is), it will be proven so and will immediately be
593 reported by the kernel (once the event is observed that
594 makes the deadlock theoretically possible).
595
596 If a deadlock is impossible (i.e. the locking rules, as
597 observed by the kernel, are mathematically correct), the
598 kernel reports nothing.
599
600 NOTE: this feature can also be enabled for rwlocks, mutexes
601 and rwsems - in which case all dependencies between these
602 different locking variants are observed and mapped too, and
603 the proof of observed correctness is also maintained for an
604 arbitrary combination of these separate locking variants.
605
606 For more details, see Documentation/lockdep-design.txt.
607
608config LOCKDEP
609 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700610 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700611 select STACKTRACE
Michal Simek79aac882010-05-25 11:33:26 +0200612 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700613 select KALLSYMS
614 select KALLSYMS_ALL
615
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700616config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700617 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700618 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
619 select LOCKDEP
620 select DEBUG_SPINLOCK
621 select DEBUG_MUTEXES
622 select DEBUG_LOCK_ALLOC
623 default n
624 help
625 This feature enables tracking lock contention points
626
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700627 For more details, see Documentation/lockstat.txt
628
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +0100629 This also enables lock events required by "perf lock",
630 subcommand of perf.
631 If you want to use "perf lock", you also need to turn on
632 CONFIG_EVENT_TRACING.
Hitoshi Mitake84c6f882010-02-04 16:08:15 +0900633
634 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +0100635 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
Hitoshi Mitake84c6f882010-02-04 16:08:15 +0900636
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700637config DEBUG_LOCKDEP
638 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700639 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700640 help
641 If you say Y here, the lock dependency engine will do
642 additional runtime checks to debug itself, at the price
643 of more runtime overhead.
644
645config TRACE_IRQFLAGS
646 bool
Steven Rostedt46b93b72010-08-31 16:35:20 -0400647 help
648 Enables hooks to interrupt enabling and disabling for
649 either tracing or lock debugging.
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700650
Frederic Weisbeckerd902db12011-06-08 19:31:56 +0200651config DEBUG_ATOMIC_SLEEP
652 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +0200653 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 depends on DEBUG_KERNEL
655 help
656 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +0200657 noisy if they are called inside atomic sections: when a spinlock is
658 held, inside an rcu read side critical section, inside preempt disabled
659 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700661config DEBUG_LOCKING_API_SELFTESTS
662 bool "Locking API boot-time self-tests"
663 depends on DEBUG_KERNEL
664 help
665 Say Y here if you want the kernel to run a short self-test during
666 bootup. The self-test checks whether common types of locking bugs
667 are detected by debugging mechanisms or not. (if you disable
668 lock debugging then those bugs wont be detected of course.)
669 The following locking APIs are covered: spinlocks, rwlocks,
670 mutexes and rwsems.
671
Ingo Molnar8637c092006-07-03 00:24:38 -0700672config STACKTRACE
673 bool
674 depends on STACKTRACE_SUPPORT
675
Stephen Boyd5ca43f62011-05-24 17:13:36 -0700676config DEBUG_STACK_USAGE
677 bool "Stack utilization instrumentation"
Tony Lucke9c31b32012-07-18 10:35:05 -0700678 depends on DEBUG_KERNEL && !IA64 && !PARISC
Stephen Boyd5ca43f62011-05-24 17:13:36 -0700679 help
680 Enables the display of the minimum amount of free stack which each
681 task has ever had available in the sysrq-T and sysrq-P debug output.
682
683 This option will slow down process creation somewhat.
684
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685config DEBUG_KOBJECT
686 bool "kobject debugging"
687 depends on DEBUG_KERNEL
688 help
689 If you say Y here, some extra kobject debugging messages will be sent
690 to the syslog.
691
692config DEBUG_HIGHMEM
693 bool "Highmem debugging"
694 depends on DEBUG_KERNEL && HIGHMEM
695 help
696 This options enables addition error checking for high memory systems.
697 Disable for production systems.
698
Catalin Marinas9b2a60c2012-10-08 16:28:13 -0700699config HAVE_DEBUG_BUGVERBOSE
700 bool
701
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702config DEBUG_BUGVERBOSE
David Rientjes6a108a12011-01-20 14:44:16 -0800703 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
Catalin Marinas9b2a60c2012-10-08 16:28:13 -0700704 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
Alexey Dobriyan8420e7e2009-12-14 18:00:25 -0800705 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706 help
707 Say Y here to make BUG() panics output the file name and line number
708 of the BUG call as well as the EIP and oops trace. This aids
709 debugging but costs about 70-100K of memory.
710
711config DEBUG_INFO
712 bool "Compile the kernel with debug info"
713 depends on DEBUG_KERNEL
714 help
715 If you say Y here the resulting kernel image will include
716 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600717 This adds debug symbols to the kernel and modules (gcc -g), and
718 is needed if you intend to use kernel crashdump or binary object
719 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 Say Y here only if you plan to debug the kernel.
721
722 If unsure, say N.
723
Andi Kleend6f4ceb2010-07-14 15:43:52 +0200724config DEBUG_INFO_REDUCED
725 bool "Reduce debugging information"
726 depends on DEBUG_INFO
727 help
728 If you say Y here gcc is instructed to generate less debugging
729 information for structure types. This means that tools that
730 need full debugging information (like kgdb or systemtap) won't
731 be happy. But if you merely need debugging information to
732 resolve line numbers there is no loss. Advantage is that
733 build directory object sizes shrink dramatically over a full
734 DEBUG_INFO build and compile times are reduced too.
735 Only works with newer gcc versions.
736
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800737config DEBUG_VM
738 bool "Debug VM"
739 depends on DEBUG_KERNEL
740 help
Nick Piggin13e74442006-01-06 00:10:58 -0800741 Enable this to turn on extended checks in the virtual-memory system
742 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800743
744 If unsure, say N.
745
Michel Lespinasseed8ea812012-10-08 16:31:45 -0700746config DEBUG_VM_RB
747 bool "Debug VM red-black trees"
748 depends on DEBUG_VM
749 help
750 Enable this to turn on more extended checks in the virtual-memory
751 system that may impact performance.
752
753 If unsure, say N.
754
Jiri Slaby59ea7462008-06-12 13:56:40 +0200755config DEBUG_VIRTUAL
756 bool "Debug VM translations"
757 depends on DEBUG_KERNEL && X86
758 help
759 Enable some costly sanity checks in virtual to page code. This can
760 catch mistakes with virt_to_page() and friends.
761
762 If unsure, say N.
763
David Howells8feae132009-01-08 12:04:47 +0000764config DEBUG_NOMMU_REGIONS
765 bool "Debug the global anon/private NOMMU mapping region tree"
766 depends on DEBUG_KERNEL && !MMU
767 help
768 This option causes the global tree of anonymous and private mapping
769 regions to be regularly checked for invalid topology.
770
Dave Hansenad775f52008-02-15 14:38:01 -0800771config DEBUG_WRITECOUNT
772 bool "Debug filesystem writers count"
773 depends on DEBUG_KERNEL
774 help
775 Enable this to catch wrong use of the writers count in struct
776 vfsmount. This will increase the size of each file struct by
777 32 bits.
778
779 If unsure, say N.
780
Mel Gorman6b74ab92008-07-23 21:26:49 -0700781config DEBUG_MEMORY_INIT
David Rientjes6a108a12011-01-20 14:44:16 -0800782 bool "Debug memory initialisation" if EXPERT
783 default !EXPERT
Mel Gorman6b74ab92008-07-23 21:26:49 -0700784 help
785 Enable this for additional checks during memory initialisation.
786 The sanity checks verify aspects of the VM such as the memory model
787 and other information provided by the architecture. Verbose
788 information will be printed at KERN_DEBUG loglevel depending
789 on the mminit_loglevel= command-line option.
790
791 If unsure, say Y
792
Dave Jones199a9af2006-09-29 01:59:00 -0700793config DEBUG_LIST
794 bool "Debug linked list manipulation"
795 depends on DEBUG_KERNEL
796 help
797 Enable this to turn on extended checks in the linked-list
798 walking routines.
799
800 If unsure, say N.
801
Artem Bityutskiy6d411e62010-10-26 14:23:05 -0700802config TEST_LIST_SORT
803 bool "Linked list sorting test"
804 depends on DEBUG_KERNEL
805 help
806 Enable this to turn on 'list_sort()' function test. This test is
807 executed only once during system boot, so affects only boot time.
808
809 If unsure, say N.
810
Jens Axboed6ec0842007-10-22 20:01:06 +0200811config DEBUG_SG
812 bool "Debug SG table operations"
813 depends on DEBUG_KERNEL
814 help
815 Enable this to turn on checks on scatter-gather tables. This can
816 help find problems with drivers that do not properly initialize
817 their sg tables.
818
819 If unsure, say N.
820
Arjan van de Ven1b2439d2008-08-15 15:29:38 -0700821config DEBUG_NOTIFIERS
822 bool "Debug notifier call chains"
823 depends on DEBUG_KERNEL
824 help
825 Enable this to turn on sanity checking for notifier call chains.
826 This is most useful for kernel developers to make sure that
827 modules properly unregister themselves from notifier chains.
828 This is a relatively cheap check but if you care about maximum
829 performance, say N.
830
David Howellse0e81732009-09-02 09:13:40 +0100831config DEBUG_CREDENTIALS
832 bool "Debug credential management"
833 depends on DEBUG_KERNEL
834 help
835 Enable this to turn on some debug checking for credential
836 management. The additional code keeps track of the number of
837 pointers from task_structs to any given cred struct, and checks to
838 see that this number never exceeds the usage count of the cred
839 struct.
840
841 Furthermore, if SELinux is enabled, this also checks that the
842 security pointer in the cred struct is never seen to be invalid.
843
844 If unsure, say N.
845
Jeff Mahoney64dec402009-01-16 13:23:35 -0500846#
847# Select this config option from the architecture Kconfig, if it
Justin P. Mattock52288b62011-08-21 20:02:13 -0700848# is preferred to always offer frame pointers as a config
Jeff Mahoney64dec402009-01-16 13:23:35 -0500849# option on the architecture (regardless of KERNEL_DEBUG):
850#
851config ARCH_WANT_FRAME_POINTERS
852 bool
853 help
854
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855config FRAME_POINTER
856 bool "Compile the kernel with frame pointers"
David Howellsb920de12008-02-08 04:19:31 -0800857 depends on DEBUG_KERNEL && \
Geert Uytterhoeven73020412011-01-22 22:35:38 +0100858 (CRIS || M68K || FRV || UML || \
Ingo Molnarda4276b2009-01-07 11:05:10 +0100859 AVR32 || SUPERH || BLACKFIN || MN10300) || \
860 ARCH_WANT_FRAME_POINTERS
861 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 help
Ingo Molnarda4276b2009-01-07 11:05:10 +0100863 If you say Y here the resulting kernel image will be slightly
864 larger and slower, but it gives very useful debugging information
865 in case of kernel bugs. (precise oopses/stacktraces/warnings)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700867config BOOT_PRINTK_DELAY
868 bool "Delay each boot printk message by N milliseconds"
869 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
870 help
871 This build option allows you to read kernel boot messages
872 by inserting a short delay after each one. The delay is
873 specified in milliseconds on the kernel command line,
874 using "boot_delay=N".
875
876 It is likely that you would also need to use "lpj=M" to preset
877 the "loops per jiffie" value.
878 See a previous boot log for the "lpj" value to use for your
879 system, and then set "lpj=M" before setting "boot_delay=N".
880 NOTE: Using this option may adversely affect SMP systems.
881 I.e., processors other than the first one may not boot up.
Anton Blanchard8edbb832011-07-05 13:32:40 +1000882 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700883 what it believes to be lockup conditions.
884
Dave Hansen2f03e3c2013-01-07 08:19:23 -0800885menu "RCU Debugging"
886
887config PROVE_RCU
888 bool "RCU debugging: prove RCU correctness"
889 depends on PROVE_LOCKING
890 default n
891 help
892 This feature enables lockdep extensions that check for correct
893 use of RCU APIs. This is currently under development. Say Y
894 if you want to debug RCU usage or help work on the PROVE_RCU
895 feature.
896
897 Say N if you are unsure.
898
899config PROVE_RCU_REPEATEDLY
900 bool "RCU debugging: don't disable PROVE_RCU on first splat"
901 depends on PROVE_RCU
902 default n
903 help
904 By itself, PROVE_RCU will disable checking upon issuing the
905 first warning (or "splat"). This feature prevents such
906 disabling, allowing multiple RCU-lockdep warnings to be printed
907 on a single reboot.
908
909 Say Y to allow multiple RCU-lockdep warnings per boot.
910
911 Say N if you are unsure.
912
913config PROVE_RCU_DELAY
914 bool "RCU debugging: preemptible RCU race provocation"
915 depends on DEBUG_KERNEL && PREEMPT_RCU
916 default n
917 help
918 There is a class of races that involve an unlikely preemption
919 of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
920 been set to INT_MIN. This feature inserts a delay at that
921 point to increase the probability of these races.
922
923 Say Y to increase probability of preemption of __rcu_read_unlock().
924
925 Say N if you are unsure.
926
927config SPARSE_RCU_POINTER
928 bool "RCU debugging: sparse-based checks for pointer usage"
929 default n
930 help
931 This feature enables the __rcu sparse annotation for
932 RCU-protected pointers. This annotation will cause sparse
933 to flag any non-RCU used of annotated pointers. This can be
934 helpful when debugging RCU usage. Please note that this feature
935 is not intended to enforce code cleanliness; it is instead merely
936 a debugging aid.
937
938 Say Y to make sparse flag questionable use of RCU-protected pointers
939
940 Say N if you are unsure.
941
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800942config RCU_TORTURE_TEST
943 tristate "torture tests for RCU"
944 depends on DEBUG_KERNEL
945 default n
946 help
947 This option provides a kernel module that runs torture tests
948 on the RCU infrastructure. The kernel module may be built
949 after the fact on the running kernel to be tested, if desired.
950
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700951 Say Y here if you want RCU torture tests to be built into
952 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800953 Say M if you want the RCU torture tests to build as a module.
954 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700955
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700956config RCU_TORTURE_TEST_RUNNABLE
957 bool "torture tests for RCU runnable by default"
958 depends on RCU_TORTURE_TEST = y
959 default n
960 help
961 This option provides a way to build the RCU torture tests
962 directly into the kernel without them starting up at boot
963 time. You can use /proc/sys/kernel/rcutorture_runnable
964 to manually override this setting. This /proc file is
965 available only when the RCU torture tests have been built
966 into the kernel.
967
968 Say Y here if you want the RCU torture tests to start during
969 boot (you probably don't).
970 Say N here if you want the RCU torture tests to start only
971 after being manually enabled via /proc.
972
Paul E. McKenneyb1637602010-06-02 16:21:38 -0700973config RCU_CPU_STALL_TIMEOUT
974 int "RCU CPU stall timeout in seconds"
Paul E. McKenneya00e0d712011-02-08 17:14:39 -0800975 depends on TREE_RCU || TREE_PREEMPT_RCU
Paul E. McKenneyb1637602010-06-02 16:21:38 -0700976 range 3 300
Paul E. McKenneyc8960542012-10-25 17:59:23 -0700977 default 21
Paul E. McKenneyb1637602010-06-02 16:21:38 -0700978 help
979 If a given RCU grace period extends more than the specified
980 number of seconds, a CPU stall warning is printed. If the
981 RCU grace period persists, additional CPU stall warnings are
982 printed at more widely spaced intervals.
983
Paul E. McKenney1ed509a2010-02-22 17:05:05 -0800984config RCU_CPU_STALL_VERBOSE
985 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
Paul E. McKenneya00e0d712011-02-08 17:14:39 -0800986 depends on TREE_PREEMPT_RCU
Paul E. McKenney55ec9362010-04-13 12:22:33 -0700987 default y
Paul E. McKenney1ed509a2010-02-22 17:05:05 -0800988 help
989 This option causes RCU to printk detailed per-task information
990 for any tasks that are stalling the current RCU grace period.
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100991
992 Say N if you are unsure.
993
Paul E. McKenney1ed509a2010-02-22 17:05:05 -0800994 Say Y if you want to enable such checks.
995
Paul E. McKenneya858af22012-01-16 13:29:10 -0800996config RCU_CPU_STALL_INFO
997 bool "Print additional diagnostics on RCU CPU stall"
998 depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
999 default n
1000 help
1001 For each stalled CPU that is aware of the current RCU grace
1002 period, print out additional per-CPU diagnostic information
1003 regarding scheduling-clock ticks, idle state, and,
1004 for RCU_FAST_NO_HZ kernels, idle-entry state.
1005
1006 Say N if you are unsure.
1007
1008 Say Y if you want to enable such diagnostics.
1009
Paul E. McKenney5c8806a2012-01-06 15:10:44 -08001010config RCU_TRACE
1011 bool "Enable tracing for RCU"
1012 depends on DEBUG_KERNEL
1013 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 Yoshikawaf4d01432010-07-21 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"