Merge tag 'for-linus-v3.9-rc1' of git://oss.sgi.com/xfs/xfs
[linux-2.6-block.git] / lib / Kconfig.debug
CommitLineData
1da177e4
LT
1
2config PRINTK_TIME
3 bool "Show timing information on printks"
d3b8b6e5 4 depends on PRINTK
1da177e4 5 help
649e6ee3
KS
6 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
1da177e4 16
5af5bcb8
MSB
17config 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
de488443
JG
28config 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
cebc04ba
AM
36config 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.
1da177e4 43
35bb5b1e
AK
44config 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
1da177e4
LT
55config MAGIC_SYSRQ
56 bool "Magic SysRq key"
f346f4b3 57 depends on !UML
1da177e4
LT
58 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
99657c78
RD
69config 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
1873e870
AK
77config 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
f71d20e9
AV
86config 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
bf4735a4
DM
102config DEBUG_FS
103 bool "Debug Filesystem"
bf4735a4
DM
104 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
ff543332
RD
109 For detailed documentation on the debugfs API, see
110 Documentation/DocBook/filesystems.
111
bf4735a4
DM
112 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
91341d4b
SR
128config DEBUG_SECTION_MISMATCH
129 bool "Enable full Section mismatch analysis"
91341d4b
SR
130 help
131 The section mismatch analysis checks if there are illegal
132 references from one section to another section.
e809ab01
MW
133 During linktime or runtime, some sections are dropped;
134 any use of code/data previously in these sections would
91341d4b 135 most likely result in an oops.
e809ab01 136 In the code, functions and variables are annotated with
6ae14171 137 __init, __cpuinit, etc. (see the full list in include/linux/init.h),
d6fbfa4f 138 which results in the code/data being placed in specific sections.
e809ab01
MW
139 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
91341d4b 145 the analysis would not catch the illegal reference.
e809ab01
MW
146 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
d6fbfa4f 150 lose valueble information about where the mismatch was
91341d4b
SR
151 introduced.
152 Running the analysis for each module/built-in.o file
e809ab01
MW
153 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.
91341d4b 158
f346f4b3
AB
159config 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
a304e1b8
DW
165config 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
58687acb
DZ
174config LOCKUP_DETECTOR
175 bool "Detect Hard and Soft Lockups"
dea20a3f 176 depends on DEBUG_KERNEL && !S390
8446f1d3 177 help
58687acb
DZ
178 Say Y here to enable the kernel to act as a watchdog to detect
179 hard and soft lockups.
180
181 Softlockups are bugs that cause the kernel to loop in kernel
5f329089 182 mode for more than 20 seconds, without giving other tasks a
58687acb
DZ
183 chance to run. The current stack trace is displayed upon
184 detection and the system will stay locked up.
8446f1d3 185
58687acb 186 Hardlockups are bugs that cause the CPU to loop in kernel mode
5f329089 187 for more than 10 seconds, without letting other interrupts have a
58687acb
DZ
188 chance to run. The current stack trace is displayed upon detection
189 and the system will stay locked up.
8446f1d3 190
58687acb 191 The overhead should be minimal. A periodic hrtimer runs to
5f329089
FLVC
192 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.
8446f1d3 197
23637d47 198config HARDLOCKUP_DETECTOR
8f1f66ed
JB
199 def_bool y
200 depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG
201 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
8446f1d3 202
fef2c9bc
DZ
203config BOOTPARAM_HARDLOCKUP_PANIC
204 bool "Panic (Reboot) On Hard Lockups"
8f1f66ed 205 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
206 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
5f329089
FLVC
209 mode with interrupts disabled for more than 10 seconds (configurable
210 using the watchdog_thresh sysctl).
fef2c9bc
DZ
211
212 Say N if unsure.
213
214config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
215 int
8f1f66ed 216 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
217 range 0 1
218 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
219 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
220
9c44bc03
IM
221config BOOTPARAM_SOFTLOCKUP_PANIC
222 bool "Panic (Reboot) On Soft Lockups"
89d7ce2a 223 depends on LOCKUP_DETECTOR
9c44bc03
IM
224 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
5f329089
FLVC
227 mode for more than 20 seconds (configurable using the watchdog_thresh
228 sysctl), without giving other tasks a chance to run.
9c44bc03
IM
229
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
e16bb1d7 240 depends on LOCKUP_DETECTOR
9c44bc03
IM
241 range 0 1
242 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
243 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
244
2a01bb38
KM
245config 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
e162b39a
MSB
265config DETECT_HUNG_TASK
266 bool "Detect Hung Tasks"
267 depends on DEBUG_KERNEL
8edbb83e 268 default LOCKUP_DETECTOR
e162b39a
MSB
269 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
e11feaa1
JM
280config 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
c51eaacc
JZ
289 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.
e11feaa1
JM
292
293 A timeout of 0 disables the check. The default is two minutes.
294 Keeping the default should be fine in most cases.
295
e162b39a
MSB
296config 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
b642b6d3
IM
319config 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
1da177e4
LT
328config 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
82f67cd9
IM
340config 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
c1a834dc
IM
349 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).
82f67cd9 353
3ac7fe5a
TG
354config 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
c6f3a97f
TG
377config 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
dc186ad7
TG
385config 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
551d55a9
MD
393config DEBUG_OBJECTS_RCU_HEAD
394 bool "Debug RCU callbacks objects"
fc2ecf7e 395 depends on DEBUG_OBJECTS
551d55a9
MD
396 help
397 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
398
e2852ae8
TH
399config 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
3ae70205
IM
407config 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
1da177e4 415config DEBUG_SLAB
4a2f0acf 416 bool "Debug slab memory allocations"
7d46d9e6 417 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
1da177e4
LT
418 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
871751e2
AV
423config DEBUG_SLAB_LEAK
424 bool "Memory leak debugging"
425 depends on DEBUG_SLAB
426
f0630fff
CL
427config SLUB_DEBUG_ON
428 bool "SLUB debugging on by default"
7d46d9e6 429 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
f0630fff
CL
430 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
8ff12cfc
CL
440config SLUB_STATS
441 default n
442 bool "Enable SLUB performance statistics"
ab4d5ed5 443 depends on SLUB && SYSFS
8ff12cfc
CL
444 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
b69ec42b
CM
453config HAVE_DEBUG_KMEMLEAK
454 bool
455
3bba00d7
CM
456config DEBUG_KMEMLEAK
457 bool "Kernel memory leak detector"
b69ec42b 458 depends on DEBUG_KERNEL && EXPERIMENTAL && HAVE_DEBUG_KMEMLEAK
79e0d9bd 459 select DEBUG_FS
3bba00d7
CM
460 select STACKTRACE if STACKTRACE_SUPPORT
461 select KALLSYMS
b60e26a2 462 select CRC32
3bba00d7
CM
463 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
bf96d1e3
CM
473 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
474 of finding leaks due to the slab objects poisoning.
475
3bba00d7
CM
476 In order to access the kmemleak file, debugfs needs to be
477 mounted (usually at /sys/kernel/debug).
478
a9d9058a
CM
479config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
480 int "Maximum kmemleak early log entries"
481 depends on DEBUG_KMEMLEAK
dfcc3e6a 482 range 200 40000
a9d9058a
CM
483 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
0822ee4a
CM
491config DEBUG_KMEMLEAK_TEST
492 tristate "Simple test for the kernel memory leak detector"
9718269a 493 depends on DEBUG_KMEMLEAK && m
0822ee4a 494 help
9718269a 495 This option enables a module that explicitly leaks memory.
0822ee4a
CM
496
497 If unsure, say N.
498
ab0155a2
JB
499config 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
1da177e4
LT
506config DEBUG_PREEMPT
507 bool "Debug preemptible kernel"
01deab98 508 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
1da177e4
LT
509 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
e7eebaf6
IM
516config DEBUG_RT_MUTEXES
517 bool "RT Mutex debugging, deadlock detection"
e7eebaf6
IM
518 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
61a87122
TG
528config RT_MUTEX_TESTER
529 bool "Built-in scriptable tester for rt-mutexes"
a1583d3e 530 depends on DEBUG_KERNEL && RT_MUTEXES
61a87122
TG
531 help
532 This option enables a rt-mutex tester.
533
1da177e4 534config DEBUG_SPINLOCK
4d9f34ad 535 bool "Spinlock and rw-lock debugging: basic checks"
1da177e4 536 depends on DEBUG_KERNEL
e335e3eb 537 select UNINLINE_SPIN_UNLOCK
1da177e4
LT
538 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
4d9f34ad
IM
544config 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
4d9f34ad
IM
551config DEBUG_LOCK_ALLOC
552 bool "Lock debugging: detect incorrect freeing of live locks"
517e7aa5 553 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
4d9f34ad
IM
554 select DEBUG_SPINLOCK
555 select DEBUG_MUTEXES
4d9f34ad
IM
556 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"
517e7aa5 567 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
4d9f34ad
IM
568 select LOCKDEP
569 select DEBUG_SPINLOCK
570 select DEBUG_MUTEXES
4d9f34ad 571 select DEBUG_LOCK_ALLOC
46b93b74 572 select TRACE_IRQFLAGS
4d9f34ad
IM
573 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
517e7aa5 610 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
4d9f34ad 611 select STACKTRACE
79aac889 612 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
4d9f34ad
IM
613 select KALLSYMS
614 select KALLSYMS_ALL
615
f20786ff 616config LOCK_STAT
fdfb870f 617 bool "Lock usage statistics"
f20786ff
PZ
618 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
a560aa48
PZ
627 For more details, see Documentation/lockstat.txt
628
dd8b1cf6
FW
629 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.
84c6f88f
HM
633
634 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
dd8b1cf6 635 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
84c6f88f 636
4d9f34ad
IM
637config DEBUG_LOCKDEP
638 bool "Lock dependency engine debugging"
517e7aa5 639 depends on DEBUG_KERNEL && LOCKDEP
4d9f34ad
IM
640 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
46b93b74
SR
647 help
648 Enables hooks to interrupt enabling and disabling for
649 either tracing or lock debugging.
4d9f34ad 650
d902db1e
FW
651config DEBUG_ATOMIC_SLEEP
652 bool "Sleep inside atomic section checking"
e8f7c70f 653 select PREEMPT_COUNT
1da177e4
LT
654 depends on DEBUG_KERNEL
655 help
656 If you say Y here, various routines which may sleep will become very
d902db1e
FW
657 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...
1da177e4 660
cae2ed9a
IM
661config 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
8637c099
IM
672config STACKTRACE
673 bool
674 depends on STACKTRACE_SUPPORT
675
5ca43f6c
SB
676config DEBUG_STACK_USAGE
677 bool "Stack utilization instrumentation"
e9c31b32 678 depends on DEBUG_KERNEL && !IA64 && !PARISC
5ca43f6c
SB
679 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
1da177e4
LT
685config 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
9b2a60c4
CM
699config HAVE_DEBUG_BUGVERBOSE
700 bool
701
1da177e4 702config DEBUG_BUGVERBOSE
6a108a14 703 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
9b2a60c4 704 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
8420e7ef 705 default y
1da177e4
LT
706 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.
b72e53f8
AD
717 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.
1da177e4
LT
720 Say Y here only if you plan to debug the kernel.
721
722 If unsure, say N.
723
d6f4ceb7
AK
724config 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
a241ec65
PM
737config DEBUG_VM
738 bool "Debug VM"
739 depends on DEBUG_KERNEL
740 help
13e7444b
NP
741 Enable this to turn on extended checks in the virtual-memory system
742 that may impact performance.
a241ec65
PM
743
744 If unsure, say N.
745
ed8ea815
ML
746config 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
59ea7463
JS
755config 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
8feae131
DH
764config 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
ad775f5a
DH
771config 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
6b74ab97 781config DEBUG_MEMORY_INIT
6a108a14
DR
782 bool "Debug memory initialisation" if EXPERT
783 default !EXPERT
6b74ab97
MG
784 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
199a9afc
DJ
793config 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
6d411e6c
AB
802config 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
d6ec0842
JA
811config 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
1b2439db
AV
821config 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
e0e81739
DH
831config 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
64dec40d
JM
846#
847# Select this config option from the architecture Kconfig, if it
52288b66 848# is preferred to always offer frame pointers as a config
64dec40d
JM
849# option on the architecture (regardless of KERNEL_DEBUG):
850#
851config ARCH_WANT_FRAME_POINTERS
852 bool
853 help
854
1da177e4
LT
855config FRAME_POINTER
856 bool "Compile the kernel with frame pointers"
b920de1b 857 depends on DEBUG_KERNEL && \
73020415 858 (CRIS || M68K || FRV || UML || \
da4276b8
IM
859 AVR32 || SUPERH || BLACKFIN || MN10300) || \
860 ARCH_WANT_FRAME_POINTERS
861 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
862 help
863 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)
1da177e4 866
bfe8df3d
RD
867config 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.
8edbb83e 882 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
bfe8df3d
RD
883 what it believes to be lockup conditions.
884
2f03e3ca
DH
885menu "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
a241ec65
PM
942config 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
31a72bce
PM
951 Say Y here if you want RCU torture tests to be built into
952 the kernel.
a241ec65
PM
953 Say M if you want the RCU torture tests to build as a module.
954 Say N if you are unsure.
8bb31b9d 955
31a72bce
PM
956config 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
b163760e
PM
973config RCU_CPU_STALL_TIMEOUT
974 int "RCU CPU stall timeout in seconds"
6bfc09e2 975 depends on RCU_STALL_COMMON
b163760e 976 range 3 300
c896054f 977 default 21
b163760e
PM
978 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
1ed509a2
PM
984config RCU_CPU_STALL_VERBOSE
985 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
a00e0d71 986 depends on TREE_PREEMPT_RCU
55ec936f 987 default y
1ed509a2
PM
988 help
989 This option causes RCU to printk detailed per-task information
990 for any tasks that are stalling the current RCU grace period.
67182ae1
PM
991
992 Say N if you are unsure.
993
1ed509a2
PM
994 Say Y if you want to enable such checks.
995
a858af28
PM
996config 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
5c8806a0
PM
1010config RCU_TRACE
1011 bool "Enable tracing for RCU"
1012 depends on DEBUG_KERNEL
52494535 1013 select TRACE_CLOCK
5c8806a0
PM
1014 help
1015 This option provides tracing in RCU which presents stats
1016 in debugfs for debugging RCU implementation.
1017
1018 Say Y here if you want to enable RCU tracing
1019 Say N if you are unsure.
1020
2f03e3ca
DH
1021endmenu # "RCU Debugging"
1022
8c1c9356
AM
1023config KPROBES_SANITY_TEST
1024 bool "Kprobes sanity tests"
1025 depends on DEBUG_KERNEL
1026 depends on KPROBES
1027 default n
1028 help
1029 This option provides for testing basic kprobes functionality on
1030 boot. A sample kprobe, jprobe and kretprobe are inserted and
1031 verified for functionality.
1032
1033 Say N if you are unsure.
1034
6dab2778
AV
1035config BACKTRACE_SELF_TEST
1036 tristate "Self test for the backtrace code"
1037 depends on DEBUG_KERNEL
1038 default n
1039 help
1040 This option provides a kernel module that can be used to test
1041 the kernel stack backtrace code. This option is not useful
1042 for distributions or general kernels, but only for kernel
1043 developers working on architecture code.
1044
ad118c54
VN
1045 Note that if you want to also test saved backtraces, you will
1046 have to enable STACKTRACE as well.
1047
6dab2778
AV
1048 Say N if you are unsure.
1049
870d6656
TH
1050config DEBUG_BLOCK_EXT_DEVT
1051 bool "Force extended block device numbers and spread them"
1052 depends on DEBUG_KERNEL
1053 depends on BLOCK
759f8ca3 1054 default n
870d6656 1055 help
0e11e342
TH
1056 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1057 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1058 YOU ARE DOING. Distros, please enable this and fix whatever
1059 is broken.
1060
870d6656
TH
1061 Conventionally, block device numbers are allocated from
1062 predetermined contiguous area. However, extended block area
1063 may introduce non-contiguous block device numbers. This
1064 option forces most block device numbers to be allocated from
1065 the extended space and spreads them to discover kernel or
1066 userland code paths which assume predetermined contiguous
1067 device number allocation.
1068
55dc7db7
TH
1069 Note that turning on this debug option shuffles all the
1070 device numbers for all IDE and SCSI devices including libata
1071 ones, so root partition specified using device number
1072 directly (via rdev or root=MAJ:MIN) won't work anymore.
1073 Textual device names (root=/dev/sdXn) will continue to work.
1074
870d6656
TH
1075 Say N if you are unsure.
1076
7c756e6e
TH
1077config DEBUG_FORCE_WEAK_PER_CPU
1078 bool "Force weak per-cpu definitions"
1079 depends on DEBUG_KERNEL
1080 help
1081 s390 and alpha require percpu variables in modules to be
1082 defined weak to work around addressing range issue which
1083 puts the following two restrictions on percpu variable
1084 definitions.
1085
1086 1. percpu symbols must be unique whether static or not
1087 2. percpu variables can't be defined inside a function
1088
1089 To ensure that generic code follows the above rules, this
1090 option forces all percpu variables to be defined as weak.
1091
44ec7abe
SB
1092config DEBUG_PER_CPU_MAPS
1093 bool "Debug access to per_cpu maps"
1094 depends on DEBUG_KERNEL
1095 depends on SMP
1096 help
1097 Say Y to verify that the per_cpu map being accessed has
1098 been set up. This adds a fair amount of code to kernel memory
1099 and decreases performance.
1100
1101 Say N if unsure.
1102
8bb31b9d
AG
1103config LKDTM
1104 tristate "Linux Kernel Dump Test Tool Module"
0347af4e 1105 depends on DEBUG_FS
fddd9cf8 1106 depends on BLOCK
8bb31b9d
AG
1107 default n
1108 help
1109 This module enables testing of the different dumping mechanisms by
1110 inducing system failures at predefined crash points.
1111 If you don't need it: say N
1112 Choose M here to compile this code as a module. The module will be
1113 called lkdtm.
1114
1115 Documentation on how to use the module can be found in
0347af4e 1116 Documentation/fault-injection/provoke-crashes.txt
6ff1cb35 1117
8d438288
AM
1118config NOTIFIER_ERROR_INJECTION
1119 tristate "Notifier error injection"
1120 depends on DEBUG_KERNEL
1121 select DEBUG_FS
1122 help
e41e85cc 1123 This option provides the ability to inject artificial errors to
8d438288
AM
1124 specified notifier chain callbacks. It is useful to test the error
1125 handling of notifier call chain failures.
1126
1127 Say N if unsure.
1128
c9d221f8
AM
1129config CPU_NOTIFIER_ERROR_INJECT
1130 tristate "CPU notifier error injection module"
f5a9f52e 1131 depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
c9d221f8
AM
1132 help
1133 This option provides a kernel module that can be used to test
e41e85cc 1134 the error handling of the cpu notifiers by injecting artificial
f5a9f52e
AM
1135 errors to CPU notifier chain callbacks. It is controlled through
1136 debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu
1137
1138 If the notifier call chain should be failed with some events
1139 notified, write the error code to "actions/<notifier event>/error".
1140
1141 Example: Inject CPU offline error (-1 == -EPERM)
1142
1143 # cd /sys/kernel/debug/notifier-error-inject/cpu
1144 # echo -1 > actions/CPU_DOWN_PREPARE/error
1145 # echo 0 > /sys/devices/system/cpu/cpu1/online
1146 bash: echo: write error: Operation not permitted
c9d221f8
AM
1147
1148 To compile this code as a module, choose M here: the module will
1149 be called cpu-notifier-error-inject.
1150
1151 If unsure, say N.
1152
048b9c35
AM
1153config PM_NOTIFIER_ERROR_INJECT
1154 tristate "PM notifier error injection module"
1155 depends on PM && NOTIFIER_ERROR_INJECTION
1156 default m if PM_DEBUG
1157 help
e41e85cc 1158 This option provides the ability to inject artificial errors to
048b9c35
AM
1159 PM notifier chain callbacks. It is controlled through debugfs
1160 interface /sys/kernel/debug/notifier-error-inject/pm
1161
1162 If the notifier call chain should be failed with some events
1163 notified, write the error code to "actions/<notifier event>/error".
1164
1165 Example: Inject PM suspend error (-12 = -ENOMEM)
1166
1167 # cd /sys/kernel/debug/notifier-error-inject/pm/
1168 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1169 # echo mem > /sys/power/state
1170 bash: echo: write error: Cannot allocate memory
1171
1172 To compile this code as a module, choose M here: the module will
1173 be called pm-notifier-error-inject.
1174
1175 If unsure, say N.
1176
9579f5bd
AM
1177config MEMORY_NOTIFIER_ERROR_INJECT
1178 tristate "Memory hotplug notifier error injection module"
1179 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
1180 help
e41e85cc 1181 This option provides the ability to inject artificial errors to
9579f5bd
AM
1182 memory hotplug notifier chain callbacks. It is controlled through
1183 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
1184
1185 If the notifier call chain should be failed with some events
1186 notified, write the error code to "actions/<notifier event>/error".
1187
1188 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
1189
1190 # cd /sys/kernel/debug/notifier-error-inject/memory
1191 # echo -12 > actions/MEM_GOING_OFFLINE/error
1192 # echo offline > /sys/devices/system/memory/memoryXXX/state
1193 bash: echo: write error: Cannot allocate memory
1194
1195 To compile this code as a module, choose M here: the module will
1196 be called pSeries-reconfig-notifier-error-inject.
1197
1198 If unsure, say N.
1199
d526e85f
BH
1200config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1201 tristate "OF reconfig notifier error injection module"
1202 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dd 1203 help
e41e85cc 1204 This option provides the ability to inject artificial errors to
d526e85f 1205 OF reconfig notifier chain callbacks. It is controlled
08dfb4dd 1206 through debugfs interface under
d526e85f 1207 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
08dfb4dd
AM
1208
1209 If the notifier call chain should be failed with some events
1210 notified, write the error code to "actions/<notifier event>/error".
1211
1212 To compile this code as a module, choose M here: the module will
1213 be called memory-notifier-error-inject.
1214
1215 If unsure, say N.
1216
6ff1cb35 1217config FAULT_INJECTION
1ab8509a
AM
1218 bool "Fault-injection framework"
1219 depends on DEBUG_KERNEL
329409ae
AM
1220 help
1221 Provide fault-injection framework.
1222 For more details, see Documentation/fault-injection/.
6ff1cb35 1223
8a8b6502 1224config FAILSLAB
1ab8509a
AM
1225 bool "Fault-injection capability for kmalloc"
1226 depends on FAULT_INJECTION
773ff60e 1227 depends on SLAB || SLUB
8a8b6502 1228 help
1ab8509a 1229 Provide fault-injection capability for kmalloc.
8a8b6502 1230
933e312e
AM
1231config FAIL_PAGE_ALLOC
1232 bool "Fault-injection capabilitiy for alloc_pages()"
1ab8509a 1233 depends on FAULT_INJECTION
933e312e 1234 help
1ab8509a 1235 Provide fault-injection capability for alloc_pages().
933e312e 1236
c17bb495 1237config FAIL_MAKE_REQUEST
86327d19 1238 bool "Fault-injection capability for disk IO"
581d4e28 1239 depends on FAULT_INJECTION && BLOCK
c17bb495 1240 help
1ab8509a 1241 Provide fault-injection capability for disk IO.
c17bb495 1242
581d4e28 1243config FAIL_IO_TIMEOUT
f4d01439 1244 bool "Fault-injection capability for faking disk interrupts"
581d4e28
JA
1245 depends on FAULT_INJECTION && BLOCK
1246 help
1247 Provide fault-injection capability on end IO handling. This
1248 will make the block layer "forget" an interrupt as configured,
1249 thus exercising the error handling.
1250
1251 Only works with drivers that use the generic timeout handling,
1252 for others it wont do anything.
1253
1b676f70
PF
1254config FAIL_MMC_REQUEST
1255 bool "Fault-injection capability for MMC IO"
1256 select DEBUG_FS
1257 depends on FAULT_INJECTION && MMC
1258 help
1259 Provide fault-injection capability for MMC IO.
1260 This will make the mmc core return data errors. This is
1261 useful to test the error handling in the mmc block device
1262 and to test how the mmc host driver handles retries from
1263 the block device.
1264
6ff1cb35
AM
1265config FAULT_INJECTION_DEBUG_FS
1266 bool "Debugfs entries for fault-injection capabilities"
1ab8509a 1267 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
6ff1cb35 1268 help
1ab8509a 1269 Enable configuration of fault-injection capabilities via debugfs.
1df49008
AM
1270
1271config FAULT_INJECTION_STACKTRACE_FILTER
1272 bool "stacktrace filter for fault-injection capabilities"
1273 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
6d690dca 1274 depends on !X86_64
1df49008 1275 select STACKTRACE
89bace65 1276 select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
1df49008
AM
1277 help
1278 Provide stacktrace filter for fault-injection capabilities
267c4025 1279
9745512c
AV
1280config LATENCYTOP
1281 bool "Latency measuring infrastructure"
625fdcaa
RD
1282 depends on HAVE_LATENCYTOP_SUPPORT
1283 depends on DEBUG_KERNEL
1284 depends on STACKTRACE_SUPPORT
1285 depends on PROC_FS
89bace65 1286 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
9745512c
AV
1287 select KALLSYMS
1288 select KALLSYMS_ALL
1289 select STACKTRACE
1290 select SCHEDSTATS
1291 select SCHED_DEBUG
9745512c
AV
1292 help
1293 Enable this option if you want to use the LatencyTOP tool
1294 to find out which userspace is blocking on what kernel operations.
1295
6a11f75b 1296source mm/Kconfig.debug
16444a8a
ACM
1297source kernel/trace/Kconfig
1298
910a742d
ML
1299config RBTREE_TEST
1300 tristate "Red-Black tree test"
1301 depends on m && DEBUG_KERNEL
1302 help
1303 A benchmark measuring the performance of the rbtree library.
1304 Also includes rbtree invariant checks.
1305
fff3fd8a
ML
1306config INTERVAL_TREE_TEST
1307 tristate "Interval tree test"
1308 depends on m && DEBUG_KERNEL
1309 help
1310 A benchmark measuring the performance of the interval tree library
1311
f212ec4b 1312config PROVIDE_OHCI1394_DMA_INIT
080de8c2 1313 bool "Remote debugging over FireWire early on boot"
f212ec4b
BK
1314 depends on PCI && X86
1315 help
1316 If you want to debug problems which hang or crash the kernel early
1317 on boot and the crashing machine has a FireWire port, you can use
1318 this feature to remotely access the memory of the crashed machine
1319 over FireWire. This employs remote DMA as part of the OHCI1394
1320 specification which is now the standard for FireWire controllers.
1321
1322 With remote DMA, you can monitor the printk buffer remotely using
1323 firescope and access all memory below 4GB using fireproxy from gdb.
1324 Even controlling a kernel debugger is possible using remote DMA.
1325
1326 Usage:
1327
1328 If ohci1394_dma=early is used as boot parameter, it will initialize
1329 all OHCI1394 controllers which are found in the PCI config space.
1330
1331 As all changes to the FireWire bus such as enabling and disabling
1332 devices cause a bus reset and thereby disable remote DMA for all
1333 devices, be sure to have the cable plugged and FireWire enabled on
1334 the debugging host before booting the debug target for debugging.
1335
1336 This code (~1k) is freed after boot. By then, the firewire stack
1337 in charge of the OHCI-1394 controllers should be used instead.
1338
1339 See Documentation/debugging-via-ohci1394.txt for more information.
9745512c 1340
080de8c2
SR
1341config FIREWIRE_OHCI_REMOTE_DMA
1342 bool "Remote debugging over FireWire with firewire-ohci"
1343 depends on FIREWIRE_OHCI
1344 help
1345 This option lets you use the FireWire bus for remote debugging
1346 with help of the firewire-ohci driver. It enables unfiltered
1347 remote DMA in firewire-ohci.
1348 See Documentation/debugging-via-ohci1394.txt for more information.
1349
1350 If unsure, say N.
1351
152de30b 1352config BUILD_DOCSRC
3794f3e8
RD
1353 bool "Build targets in Documentation/ tree"
1354 depends on HEADERS_CHECK
1355 help
1356 This option attempts to build objects from the source files in the
1357 kernel Documentation/ tree.
1358
1359 Say N if you are unsure.
1360
e9d376f0 1361config DYNAMIC_DEBUG
86151fdf 1362 bool "Enable dynamic printk() support"
346e15be
JB
1363 default n
1364 depends on PRINTK
86151fdf 1365 depends on DEBUG_FS
346e15be
JB
1366 help
1367
1368 Compiles debug level messages into the kernel, which would not
1369 otherwise be available at runtime. These messages can then be
86151fdf
JB
1370 enabled/disabled based on various levels of scope - per source file,
1371 function, module, format string, and line number. This mechanism
29e36c9f
JC
1372 implicitly compiles in all pr_debug() and dev_dbg() calls, which
1373 enlarges the kernel text size by about 2%.
1374
1375 If a source file is compiled with DEBUG flag set, any
1376 pr_debug() calls in it are enabled by default, but can be
1377 disabled at runtime as below. Note that DEBUG flag is
1378 turned on by many CONFIG_*DEBUG* options.
346e15be
JB
1379
1380 Usage:
1381
2b2f68b5 1382 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
86151fdf
JB
1383 which is contained in the 'debugfs' filesystem. Thus, the debugfs
1384 filesystem must first be mounted before making use of this feature.
2b2f68b5 1385 We refer the control file as: <debugfs>/dynamic_debug/control. This
86151fdf
JB
1386 file contains a list of the debug statements that can be enabled. The
1387 format for each line of the file is:
346e15be 1388
86151fdf 1389 filename:lineno [module]function flags format
346e15be 1390
86151fdf
JB
1391 filename : source file of the debug statement
1392 lineno : line number of the debug statement
1393 module : module that contains the debug statement
1394 function : function that contains the debug statement
29e36c9f 1395 flags : '=p' means the line is turned 'on' for printing
86151fdf 1396 format : the format used for the debug statement
346e15be
JB
1397
1398 From a live system:
1399
2b2f68b5 1400 nullarbor:~ # cat <debugfs>/dynamic_debug/control
86151fdf 1401 # filename:lineno [module]function flags format
29e36c9f
JC
1402 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
1403 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
1404 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
346e15be 1405
86151fdf 1406 Example usage:
346e15be 1407
86151fdf
JB
1408 // enable the message at line 1603 of file svcsock.c
1409 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
2b2f68b5 1410 <debugfs>/dynamic_debug/control
346e15be 1411
86151fdf
JB
1412 // enable all the messages in file svcsock.c
1413 nullarbor:~ # echo -n 'file svcsock.c +p' >
2b2f68b5 1414 <debugfs>/dynamic_debug/control
346e15be 1415
86151fdf
JB
1416 // enable all the messages in the NFS server module
1417 nullarbor:~ # echo -n 'module nfsd +p' >
2b2f68b5 1418 <debugfs>/dynamic_debug/control
346e15be 1419
86151fdf
JB
1420 // enable all 12 messages in the function svc_process()
1421 nullarbor:~ # echo -n 'func svc_process +p' >
2b2f68b5 1422 <debugfs>/dynamic_debug/control
346e15be 1423
86151fdf
JB
1424 // disable all 12 messages in the function svc_process()
1425 nullarbor:~ # echo -n 'func svc_process -p' >
2b2f68b5 1426 <debugfs>/dynamic_debug/control
346e15be 1427
86151fdf 1428 See Documentation/dynamic-debug-howto.txt for additional information.
346e15be 1429
5ee00bd4
JR
1430config DMA_API_DEBUG
1431 bool "Enable debugging of DMA-API usage"
1432 depends on HAVE_DMA_API_DEBUG
1433 help
1434 Enable this option to debug the use of the DMA API by device drivers.
1435 With this option you will be able to detect common bugs in device
1436 drivers like double-freeing of DMA mappings or freeing mappings that
1437 were never allocated.
1438 This option causes a performance degredation. Use only if you want
1439 to debug device drivers. If unsure, say N.
346e15be 1440
86a89380
LB
1441config ATOMIC64_SELFTEST
1442 bool "Perform an atomic64_t self-test at boot"
1443 help
1444 Enable this option to test the atomic64_t functions at boot.
1445
1446 If unsure, say N.
1447
400fb7f6
DW
1448config ASYNC_RAID6_TEST
1449 tristate "Self test for hardware accelerated raid6 recovery"
1450 depends on ASYNC_RAID6_RECOV
1451 select ASYNC_MEMCPY
1452 ---help---
1453 This is a one-shot self test that permutes through the
1454 recovery of all the possible two disk failure scenarios for a
1455 N-disk array. Recovery is performed with the asynchronous
1456 raid6 recovery routines, and will optionally use an offload
1457 engine if one is available.
1458
1459 If unsure, say N.
1460
267c4025 1461source "samples/Kconfig"
dc7d5527
JW
1462
1463source "lib/Kconfig.kgdb"
0a4af3b0
PE
1464
1465source "lib/Kconfig.kmemcheck"
33ee3b2e
AD
1466
1467config TEST_KSTRTOX
1468 tristate "Test kstrto*() family of functions at runtime"