xref: /openbmc/linux/lib/Kconfig.debug (revision 9d749629)
1
2config PRINTK_TIME
3	bool "Show timing information on printks"
4	depends on PRINTK
5	help
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
16
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
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
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.
43
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
55config MAGIC_SYSRQ
56	bool "Magic SysRq key"
57	depends on !UML
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
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
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
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
102config DEBUG_FS
103	bool "Debug Filesystem"
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
109	  For detailed documentation on the debugfs API, see
110	  Documentation/DocBook/filesystems.
111
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
128config DEBUG_SECTION_MISMATCH
129	bool "Enable full Section mismatch analysis"
130	help
131	  The section mismatch analysis checks if there are illegal
132	  references from one section to another section.
133	  During linktime or runtime, some sections are dropped;
134	  any use of code/data previously in these sections would
135	  most likely result in an oops.
136	  In the code, functions and variables are annotated with
137	  __init, __cpuinit, etc. (see the full list in include/linux/init.h),
138	  which results in the code/data being placed in specific sections.
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
145	    the analysis would not catch the illegal reference.
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
150	    lose valueble information about where the mismatch was
151	    introduced.
152	    Running the analysis for each module/built-in.o file
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.
158
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
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
174config LOCKUP_DETECTOR
175	bool "Detect Hard and Soft Lockups"
176	depends on DEBUG_KERNEL && !S390
177	help
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
182	  mode for more than 20 seconds, without giving other tasks a
183	  chance to run.  The current stack trace is displayed upon
184	  detection and the system will stay locked up.
185
186	  Hardlockups are bugs that cause the CPU to loop in kernel mode
187	  for more than 10 seconds, without letting other interrupts have a
188	  chance to run.  The current stack trace is displayed upon detection
189	  and the system will stay locked up.
190
191	  The overhead should be minimal.  A periodic hrtimer runs to
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.
197
198config HARDLOCKUP_DETECTOR
199	def_bool y
200	depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG
201	depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
202
203config BOOTPARAM_HARDLOCKUP_PANIC
204	bool "Panic (Reboot) On Hard Lockups"
205	depends on HARDLOCKUP_DETECTOR
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
209	  mode with interrupts disabled for more than 10 seconds (configurable
210	  using the watchdog_thresh sysctl).
211
212	  Say N if unsure.
213
214config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
215	int
216	depends on HARDLOCKUP_DETECTOR
217	range 0 1
218	default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
219	default 1 if BOOTPARAM_HARDLOCKUP_PANIC
220
221config BOOTPARAM_SOFTLOCKUP_PANIC
222	bool "Panic (Reboot) On Soft Lockups"
223	depends on LOCKUP_DETECTOR
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
227	  mode for more than 20 seconds (configurable using the watchdog_thresh
228	  sysctl), without giving other tasks a chance to run.
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
240	depends on LOCKUP_DETECTOR
241	range 0 1
242	default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
243	default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
244
245config PANIC_ON_OOPS
246	bool "Panic on Oops"
247	help
248	  Say Y here to enable the kernel to panic when it oopses. This
249	  has the same effect as setting oops=panic on the kernel command
250	  line.
251
252	  This feature is useful to ensure that the kernel does not do
253	  anything erroneous after an oops which could result in data
254	  corruption or other issues.
255
256	  Say N if unsure.
257
258config PANIC_ON_OOPS_VALUE
259	int
260	range 0 1
261	default 0 if !PANIC_ON_OOPS
262	default 1 if PANIC_ON_OOPS
263
264config DETECT_HUNG_TASK
265	bool "Detect Hung Tasks"
266	depends on DEBUG_KERNEL
267	default LOCKUP_DETECTOR
268	help
269	  Say Y here to enable the kernel to detect "hung tasks",
270	  which are bugs that cause the task to be stuck in
271	  uninterruptible "D" state indefinitiley.
272
273	  When a hung task is detected, the kernel will print the
274	  current stack trace (which you should report), but the
275	  task will stay in uninterruptible state. If lockdep is
276	  enabled then all held locks will also be reported. This
277	  feature has negligible overhead.
278
279config DEFAULT_HUNG_TASK_TIMEOUT
280	int "Default timeout for hung task detection (in seconds)"
281	depends on DETECT_HUNG_TASK
282	default 120
283	help
284	  This option controls the default timeout (in seconds) used
285	  to determine when a task has become non-responsive and should
286	  be considered hung.
287
288	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
289	  sysctl or by writing a value to
290	  /proc/sys/kernel/hung_task_timeout_secs.
291
292	  A timeout of 0 disables the check.  The default is two minutes.
293	  Keeping the default should be fine in most cases.
294
295config BOOTPARAM_HUNG_TASK_PANIC
296	bool "Panic (Reboot) On Hung Tasks"
297	depends on DETECT_HUNG_TASK
298	help
299	  Say Y here to enable the kernel to panic on "hung tasks",
300	  which are bugs that cause the kernel to leave a task stuck
301	  in uninterruptible "D" state.
302
303	  The panic can be used in combination with panic_timeout,
304	  to cause the system to reboot automatically after a
305	  hung task has been detected. This feature is useful for
306	  high-availability systems that have uptime guarantees and
307	  where a hung tasks must be resolved ASAP.
308
309	  Say N if unsure.
310
311config BOOTPARAM_HUNG_TASK_PANIC_VALUE
312	int
313	depends on DETECT_HUNG_TASK
314	range 0 1
315	default 0 if !BOOTPARAM_HUNG_TASK_PANIC
316	default 1 if BOOTPARAM_HUNG_TASK_PANIC
317
318config SCHED_DEBUG
319	bool "Collect scheduler debugging info"
320	depends on DEBUG_KERNEL && PROC_FS
321	default y
322	help
323	  If you say Y here, the /proc/sched_debug file will be provided
324	  that can help debug the scheduler. The runtime overhead of this
325	  option is minimal.
326
327config SCHEDSTATS
328	bool "Collect scheduler statistics"
329	depends on DEBUG_KERNEL && PROC_FS
330	help
331	  If you say Y here, additional code will be inserted into the
332	  scheduler and related routines to collect statistics about
333	  scheduler behavior and provide them in /proc/schedstat.  These
334	  stats may be useful for both tuning and debugging the scheduler
335	  If you aren't debugging the scheduler or trying to tune a specific
336	  application, you can say N to avoid the very slight overhead
337	  this adds.
338
339config TIMER_STATS
340	bool "Collect kernel timers statistics"
341	depends on DEBUG_KERNEL && PROC_FS
342	help
343	  If you say Y here, additional code will be inserted into the
344	  timer routines to collect statistics about kernel timers being
345	  reprogrammed. The statistics can be read from /proc/timer_stats.
346	  The statistics collection is started by writing 1 to /proc/timer_stats,
347	  writing 0 stops it. This feature is useful to collect information
348	  about timer usage patterns in kernel and userspace. This feature
349	  is lightweight if enabled in the kernel config but not activated
350	  (it defaults to deactivated on bootup and will only be activated
351	  if some application like powertop activates it explicitly).
352
353config DEBUG_OBJECTS
354	bool "Debug object operations"
355	depends on DEBUG_KERNEL
356	help
357	  If you say Y here, additional code will be inserted into the
358	  kernel to track the life time of various objects and validate
359	  the operations on those objects.
360
361config DEBUG_OBJECTS_SELFTEST
362	bool "Debug objects selftest"
363	depends on DEBUG_OBJECTS
364	help
365	  This enables the selftest of the object debug code.
366
367config DEBUG_OBJECTS_FREE
368	bool "Debug objects in freed memory"
369	depends on DEBUG_OBJECTS
370	help
371	  This enables checks whether a k/v free operation frees an area
372	  which contains an object which has not been deactivated
373	  properly. This can make kmalloc/kfree-intensive workloads
374	  much slower.
375
376config DEBUG_OBJECTS_TIMERS
377	bool "Debug timer objects"
378	depends on DEBUG_OBJECTS
379	help
380	  If you say Y here, additional code will be inserted into the
381	  timer routines to track the life time of timer objects and
382	  validate the timer operations.
383
384config DEBUG_OBJECTS_WORK
385	bool "Debug work objects"
386	depends on DEBUG_OBJECTS
387	help
388	  If you say Y here, additional code will be inserted into the
389	  work queue routines to track the life time of work objects and
390	  validate the work operations.
391
392config DEBUG_OBJECTS_RCU_HEAD
393	bool "Debug RCU callbacks objects"
394	depends on DEBUG_OBJECTS
395	help
396	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
397
398config DEBUG_OBJECTS_PERCPU_COUNTER
399	bool "Debug percpu counter objects"
400	depends on DEBUG_OBJECTS
401	help
402	  If you say Y here, additional code will be inserted into the
403	  percpu counter routines to track the life time of percpu counter
404	  objects and validate the percpu counter operations.
405
406config DEBUG_OBJECTS_ENABLE_DEFAULT
407	int "debug_objects bootup default value (0-1)"
408        range 0 1
409        default "1"
410        depends on DEBUG_OBJECTS
411        help
412          Debug objects boot parameter default value
413
414config DEBUG_SLAB
415	bool "Debug slab memory allocations"
416	depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
417	help
418	  Say Y here to have the kernel do limited verification on memory
419	  allocation as well as poisoning memory on free to catch use of freed
420	  memory. This can make kmalloc/kfree-intensive workloads much slower.
421
422config DEBUG_SLAB_LEAK
423	bool "Memory leak debugging"
424	depends on DEBUG_SLAB
425
426config SLUB_DEBUG_ON
427	bool "SLUB debugging on by default"
428	depends on SLUB && SLUB_DEBUG && !KMEMCHECK
429	default n
430	help
431	  Boot with debugging on by default. SLUB boots by default with
432	  the runtime debug capabilities switched off. Enabling this is
433	  equivalent to specifying the "slub_debug" parameter on boot.
434	  There is no support for more fine grained debug control like
435	  possible with slub_debug=xxx. SLUB debugging may be switched
436	  off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
437	  "slub_debug=-".
438
439config SLUB_STATS
440	default n
441	bool "Enable SLUB performance statistics"
442	depends on SLUB && SYSFS
443	help
444	  SLUB statistics are useful to debug SLUBs allocation behavior in
445	  order find ways to optimize the allocator. This should never be
446	  enabled for production use since keeping statistics slows down
447	  the allocator by a few percentage points. The slabinfo command
448	  supports the determination of the most active slabs to figure
449	  out which slabs are relevant to a particular load.
450	  Try running: slabinfo -DA
451
452config HAVE_DEBUG_KMEMLEAK
453	bool
454
455config DEBUG_KMEMLEAK
456	bool "Kernel memory leak detector"
457	depends on DEBUG_KERNEL && EXPERIMENTAL && HAVE_DEBUG_KMEMLEAK
458	select DEBUG_FS
459	select STACKTRACE if STACKTRACE_SUPPORT
460	select KALLSYMS
461	select CRC32
462	help
463	  Say Y here if you want to enable the memory leak
464	  detector. The memory allocation/freeing is traced in a way
465	  similar to the Boehm's conservative garbage collector, the
466	  difference being that the orphan objects are not freed but
467	  only shown in /sys/kernel/debug/kmemleak. Enabling this
468	  feature will introduce an overhead to memory
469	  allocations. See Documentation/kmemleak.txt for more
470	  details.
471
472	  Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
473	  of finding leaks due to the slab objects poisoning.
474
475	  In order to access the kmemleak file, debugfs needs to be
476	  mounted (usually at /sys/kernel/debug).
477
478config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
479	int "Maximum kmemleak early log entries"
480	depends on DEBUG_KMEMLEAK
481	range 200 40000
482	default 400
483	help
484	  Kmemleak must track all the memory allocations to avoid
485	  reporting false positives. Since memory may be allocated or
486	  freed before kmemleak is initialised, an early log buffer is
487	  used to store these actions. If kmemleak reports "early log
488	  buffer exceeded", please increase this value.
489
490config DEBUG_KMEMLEAK_TEST
491	tristate "Simple test for the kernel memory leak detector"
492	depends on DEBUG_KMEMLEAK && m
493	help
494	  This option enables a module that explicitly leaks memory.
495
496	  If unsure, say N.
497
498config DEBUG_KMEMLEAK_DEFAULT_OFF
499	bool "Default kmemleak to off"
500	depends on DEBUG_KMEMLEAK
501	help
502	  Say Y here to disable kmemleak by default. It can then be enabled
503	  on the command line via kmemleak=on.
504
505config DEBUG_PREEMPT
506	bool "Debug preemptible kernel"
507	depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
508	default y
509	help
510	  If you say Y here then the kernel will use a debug variant of the
511	  commonly used smp_processor_id() function and will print warnings
512	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
513	  will detect preemption count underflows.
514
515config DEBUG_RT_MUTEXES
516	bool "RT Mutex debugging, deadlock detection"
517	depends on DEBUG_KERNEL && RT_MUTEXES
518	help
519	 This allows rt mutex semantics violations and rt mutex related
520	 deadlocks (lockups) to be detected and reported automatically.
521
522config DEBUG_PI_LIST
523	bool
524	default y
525	depends on DEBUG_RT_MUTEXES
526
527config RT_MUTEX_TESTER
528	bool "Built-in scriptable tester for rt-mutexes"
529	depends on DEBUG_KERNEL && RT_MUTEXES
530	help
531	  This option enables a rt-mutex tester.
532
533config DEBUG_SPINLOCK
534	bool "Spinlock and rw-lock debugging: basic checks"
535	depends on DEBUG_KERNEL
536	select UNINLINE_SPIN_UNLOCK
537	help
538	  Say Y here and build SMP to catch missing spinlock initialization
539	  and certain other kinds of spinlock errors commonly made.  This is
540	  best used in conjunction with the NMI watchdog so that spinlock
541	  deadlocks are also debuggable.
542
543config DEBUG_MUTEXES
544	bool "Mutex debugging: basic checks"
545	depends on DEBUG_KERNEL
546	help
547	 This feature allows mutex semantics violations to be detected and
548	 reported.
549
550config DEBUG_LOCK_ALLOC
551	bool "Lock debugging: detect incorrect freeing of live locks"
552	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
553	select DEBUG_SPINLOCK
554	select DEBUG_MUTEXES
555	select LOCKDEP
556	help
557	 This feature will check whether any held lock (spinlock, rwlock,
558	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
559	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
560	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
561	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
562	 held during task exit.
563
564config PROVE_LOCKING
565	bool "Lock debugging: prove locking correctness"
566	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
567	select LOCKDEP
568	select DEBUG_SPINLOCK
569	select DEBUG_MUTEXES
570	select DEBUG_LOCK_ALLOC
571	select TRACE_IRQFLAGS
572	default n
573	help
574	 This feature enables the kernel to prove that all locking
575	 that occurs in the kernel runtime is mathematically
576	 correct: that under no circumstance could an arbitrary (and
577	 not yet triggered) combination of observed locking
578	 sequences (on an arbitrary number of CPUs, running an
579	 arbitrary number of tasks and interrupt contexts) cause a
580	 deadlock.
581
582	 In short, this feature enables the kernel to report locking
583	 related deadlocks before they actually occur.
584
585	 The proof does not depend on how hard and complex a
586	 deadlock scenario would be to trigger: how many
587	 participant CPUs, tasks and irq-contexts would be needed
588	 for it to trigger. The proof also does not depend on
589	 timing: if a race and a resulting deadlock is possible
590	 theoretically (no matter how unlikely the race scenario
591	 is), it will be proven so and will immediately be
592	 reported by the kernel (once the event is observed that
593	 makes the deadlock theoretically possible).
594
595	 If a deadlock is impossible (i.e. the locking rules, as
596	 observed by the kernel, are mathematically correct), the
597	 kernel reports nothing.
598
599	 NOTE: this feature can also be enabled for rwlocks, mutexes
600	 and rwsems - in which case all dependencies between these
601	 different locking variants are observed and mapped too, and
602	 the proof of observed correctness is also maintained for an
603	 arbitrary combination of these separate locking variants.
604
605	 For more details, see Documentation/lockdep-design.txt.
606
607config LOCKDEP
608	bool
609	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
610	select STACKTRACE
611	select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
612	select KALLSYMS
613	select KALLSYMS_ALL
614
615config LOCK_STAT
616	bool "Lock usage statistics"
617	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
618	select LOCKDEP
619	select DEBUG_SPINLOCK
620	select DEBUG_MUTEXES
621	select DEBUG_LOCK_ALLOC
622	default n
623	help
624	 This feature enables tracking lock contention points
625
626	 For more details, see Documentation/lockstat.txt
627
628	 This also enables lock events required by "perf lock",
629	 subcommand of perf.
630	 If you want to use "perf lock", you also need to turn on
631	 CONFIG_EVENT_TRACING.
632
633	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
634	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
635
636config DEBUG_LOCKDEP
637	bool "Lock dependency engine debugging"
638	depends on DEBUG_KERNEL && LOCKDEP
639	help
640	  If you say Y here, the lock dependency engine will do
641	  additional runtime checks to debug itself, at the price
642	  of more runtime overhead.
643
644config TRACE_IRQFLAGS
645	bool
646	help
647	  Enables hooks to interrupt enabling and disabling for
648	  either tracing or lock debugging.
649
650config DEBUG_ATOMIC_SLEEP
651	bool "Sleep inside atomic section checking"
652	select PREEMPT_COUNT
653	depends on DEBUG_KERNEL
654	help
655	  If you say Y here, various routines which may sleep will become very
656	  noisy if they are called inside atomic sections: when a spinlock is
657	  held, inside an rcu read side critical section, inside preempt disabled
658	  sections, inside an interrupt, etc...
659
660config DEBUG_LOCKING_API_SELFTESTS
661	bool "Locking API boot-time self-tests"
662	depends on DEBUG_KERNEL
663	help
664	  Say Y here if you want the kernel to run a short self-test during
665	  bootup. The self-test checks whether common types of locking bugs
666	  are detected by debugging mechanisms or not. (if you disable
667	  lock debugging then those bugs wont be detected of course.)
668	  The following locking APIs are covered: spinlocks, rwlocks,
669	  mutexes and rwsems.
670
671config STACKTRACE
672	bool
673	depends on STACKTRACE_SUPPORT
674
675config DEBUG_STACK_USAGE
676	bool "Stack utilization instrumentation"
677	depends on DEBUG_KERNEL && !IA64 && !PARISC
678	help
679	  Enables the display of the minimum amount of free stack which each
680	  task has ever had available in the sysrq-T and sysrq-P debug output.
681
682	  This option will slow down process creation somewhat.
683
684config DEBUG_KOBJECT
685	bool "kobject debugging"
686	depends on DEBUG_KERNEL
687	help
688	  If you say Y here, some extra kobject debugging messages will be sent
689	  to the syslog.
690
691config DEBUG_HIGHMEM
692	bool "Highmem debugging"
693	depends on DEBUG_KERNEL && HIGHMEM
694	help
695	  This options enables addition error checking for high memory systems.
696	  Disable for production systems.
697
698config HAVE_DEBUG_BUGVERBOSE
699	bool
700
701config DEBUG_BUGVERBOSE
702	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
703	depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
704	default y
705	help
706	  Say Y here to make BUG() panics output the file name and line number
707	  of the BUG call as well as the EIP and oops trace.  This aids
708	  debugging but costs about 70-100K of memory.
709
710config DEBUG_INFO
711	bool "Compile the kernel with debug info"
712	depends on DEBUG_KERNEL
713	help
714          If you say Y here the resulting kernel image will include
715	  debugging info resulting in a larger kernel image.
716	  This adds debug symbols to the kernel and modules (gcc -g), and
717	  is needed if you intend to use kernel crashdump or binary object
718	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
719	  Say Y here only if you plan to debug the kernel.
720
721	  If unsure, say N.
722
723config DEBUG_INFO_REDUCED
724	bool "Reduce debugging information"
725	depends on DEBUG_INFO
726	help
727	  If you say Y here gcc is instructed to generate less debugging
728	  information for structure types. This means that tools that
729	  need full debugging information (like kgdb or systemtap) won't
730	  be happy. But if you merely need debugging information to
731	  resolve line numbers there is no loss. Advantage is that
732	  build directory object sizes shrink dramatically over a full
733	  DEBUG_INFO build and compile times are reduced too.
734	  Only works with newer gcc versions.
735
736config DEBUG_VM
737	bool "Debug VM"
738	depends on DEBUG_KERNEL
739	help
740	  Enable this to turn on extended checks in the virtual-memory system
741          that may impact performance.
742
743	  If unsure, say N.
744
745config DEBUG_VM_RB
746	bool "Debug VM red-black trees"
747	depends on DEBUG_VM
748	help
749	  Enable this to turn on more extended checks in the virtual-memory
750	  system that may impact performance.
751
752	  If unsure, say N.
753
754config DEBUG_VIRTUAL
755	bool "Debug VM translations"
756	depends on DEBUG_KERNEL && X86
757	help
758	  Enable some costly sanity checks in virtual to page code. This can
759	  catch mistakes with virt_to_page() and friends.
760
761	  If unsure, say N.
762
763config DEBUG_NOMMU_REGIONS
764	bool "Debug the global anon/private NOMMU mapping region tree"
765	depends on DEBUG_KERNEL && !MMU
766	help
767	  This option causes the global tree of anonymous and private mapping
768	  regions to be regularly checked for invalid topology.
769
770config DEBUG_WRITECOUNT
771	bool "Debug filesystem writers count"
772	depends on DEBUG_KERNEL
773	help
774	  Enable this to catch wrong use of the writers count in struct
775	  vfsmount.  This will increase the size of each file struct by
776	  32 bits.
777
778	  If unsure, say N.
779
780config DEBUG_MEMORY_INIT
781	bool "Debug memory initialisation" if EXPERT
782	default !EXPERT
783	help
784	  Enable this for additional checks during memory initialisation.
785	  The sanity checks verify aspects of the VM such as the memory model
786	  and other information provided by the architecture. Verbose
787	  information will be printed at KERN_DEBUG loglevel depending
788	  on the mminit_loglevel= command-line option.
789
790	  If unsure, say Y
791
792config DEBUG_LIST
793	bool "Debug linked list manipulation"
794	depends on DEBUG_KERNEL
795	help
796	  Enable this to turn on extended checks in the linked-list
797	  walking routines.
798
799	  If unsure, say N.
800
801config TEST_LIST_SORT
802	bool "Linked list sorting test"
803	depends on DEBUG_KERNEL
804	help
805	  Enable this to turn on 'list_sort()' function test. This test is
806	  executed only once during system boot, so affects only boot time.
807
808	  If unsure, say N.
809
810config DEBUG_SG
811	bool "Debug SG table operations"
812	depends on DEBUG_KERNEL
813	help
814	  Enable this to turn on checks on scatter-gather tables. This can
815	  help find problems with drivers that do not properly initialize
816	  their sg tables.
817
818	  If unsure, say N.
819
820config DEBUG_NOTIFIERS
821	bool "Debug notifier call chains"
822	depends on DEBUG_KERNEL
823	help
824	  Enable this to turn on sanity checking for notifier call chains.
825	  This is most useful for kernel developers to make sure that
826	  modules properly unregister themselves from notifier chains.
827	  This is a relatively cheap check but if you care about maximum
828	  performance, say N.
829
830config DEBUG_CREDENTIALS
831	bool "Debug credential management"
832	depends on DEBUG_KERNEL
833	help
834	  Enable this to turn on some debug checking for credential
835	  management.  The additional code keeps track of the number of
836	  pointers from task_structs to any given cred struct, and checks to
837	  see that this number never exceeds the usage count of the cred
838	  struct.
839
840	  Furthermore, if SELinux is enabled, this also checks that the
841	  security pointer in the cred struct is never seen to be invalid.
842
843	  If unsure, say N.
844
845#
846# Select this config option from the architecture Kconfig, if it
847# is preferred to always offer frame pointers as a config
848# option on the architecture (regardless of KERNEL_DEBUG):
849#
850config ARCH_WANT_FRAME_POINTERS
851	bool
852	help
853
854config FRAME_POINTER
855	bool "Compile the kernel with frame pointers"
856	depends on DEBUG_KERNEL && \
857		(CRIS || M68K || FRV || UML || \
858		 AVR32 || SUPERH || BLACKFIN || MN10300) || \
859		ARCH_WANT_FRAME_POINTERS
860	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
861	help
862	  If you say Y here the resulting kernel image will be slightly
863	  larger and slower, but it gives very useful debugging information
864	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
865
866config BOOT_PRINTK_DELAY
867	bool "Delay each boot printk message by N milliseconds"
868	depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
869	help
870	  This build option allows you to read kernel boot messages
871	  by inserting a short delay after each one.  The delay is
872	  specified in milliseconds on the kernel command line,
873	  using "boot_delay=N".
874
875	  It is likely that you would also need to use "lpj=M" to preset
876	  the "loops per jiffie" value.
877	  See a previous boot log for the "lpj" value to use for your
878	  system, and then set "lpj=M" before setting "boot_delay=N".
879	  NOTE:  Using this option may adversely affect SMP systems.
880	  I.e., processors other than the first one may not boot up.
881	  BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
882	  what it believes to be lockup conditions.
883
884menu "RCU Debugging"
885
886config PROVE_RCU
887	bool "RCU debugging: prove RCU correctness"
888	depends on PROVE_LOCKING
889	default n
890	help
891	 This feature enables lockdep extensions that check for correct
892	 use of RCU APIs.  This is currently under development.  Say Y
893	 if you want to debug RCU usage or help work on the PROVE_RCU
894	 feature.
895
896	 Say N if you are unsure.
897
898config PROVE_RCU_REPEATEDLY
899	bool "RCU debugging: don't disable PROVE_RCU on first splat"
900	depends on PROVE_RCU
901	default n
902	help
903	 By itself, PROVE_RCU will disable checking upon issuing the
904	 first warning (or "splat").  This feature prevents such
905	 disabling, allowing multiple RCU-lockdep warnings to be printed
906	 on a single reboot.
907
908	 Say Y to allow multiple RCU-lockdep warnings per boot.
909
910	 Say N if you are unsure.
911
912config PROVE_RCU_DELAY
913	bool "RCU debugging: preemptible RCU race provocation"
914	depends on DEBUG_KERNEL && PREEMPT_RCU
915	default n
916	help
917	 There is a class of races that involve an unlikely preemption
918	 of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
919	 been set to INT_MIN.  This feature inserts a delay at that
920	 point to increase the probability of these races.
921
922	 Say Y to increase probability of preemption of __rcu_read_unlock().
923
924	 Say N if you are unsure.
925
926config SPARSE_RCU_POINTER
927	bool "RCU debugging: sparse-based checks for pointer usage"
928	default n
929	help
930	 This feature enables the __rcu sparse annotation for
931	 RCU-protected pointers.  This annotation will cause sparse
932	 to flag any non-RCU used of annotated pointers.  This can be
933	 helpful when debugging RCU usage.  Please note that this feature
934	 is not intended to enforce code cleanliness; it is instead merely
935	 a debugging aid.
936
937	 Say Y to make sparse flag questionable use of RCU-protected pointers
938
939	 Say N if you are unsure.
940
941config RCU_TORTURE_TEST
942	tristate "torture tests for RCU"
943	depends on DEBUG_KERNEL
944	default n
945	help
946	  This option provides a kernel module that runs torture tests
947	  on the RCU infrastructure.  The kernel module may be built
948	  after the fact on the running kernel to be tested, if desired.
949
950	  Say Y here if you want RCU torture tests to be built into
951	  the kernel.
952	  Say M if you want the RCU torture tests to build as a module.
953	  Say N if you are unsure.
954
955config RCU_TORTURE_TEST_RUNNABLE
956	bool "torture tests for RCU runnable by default"
957	depends on RCU_TORTURE_TEST = y
958	default n
959	help
960	  This option provides a way to build the RCU torture tests
961	  directly into the kernel without them starting up at boot
962	  time.  You can use /proc/sys/kernel/rcutorture_runnable
963	  to manually override this setting.  This /proc file is
964	  available only when the RCU torture tests have been built
965	  into the kernel.
966
967	  Say Y here if you want the RCU torture tests to start during
968	  boot (you probably don't).
969	  Say N here if you want the RCU torture tests to start only
970	  after being manually enabled via /proc.
971
972config RCU_CPU_STALL_TIMEOUT
973	int "RCU CPU stall timeout in seconds"
974	depends on RCU_STALL_COMMON
975	range 3 300
976	default 21
977	help
978	  If a given RCU grace period extends more than the specified
979	  number of seconds, a CPU stall warning is printed.  If the
980	  RCU grace period persists, additional CPU stall warnings are
981	  printed at more widely spaced intervals.
982
983config RCU_CPU_STALL_VERBOSE
984	bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
985	depends on TREE_PREEMPT_RCU
986	default y
987	help
988	  This option causes RCU to printk detailed per-task information
989	  for any tasks that are stalling the current RCU grace period.
990
991	  Say N if you are unsure.
992
993	  Say Y if you want to enable such checks.
994
995config RCU_CPU_STALL_INFO
996	bool "Print additional diagnostics on RCU CPU stall"
997	depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
998	default n
999	help
1000	  For each stalled CPU that is aware of the current RCU grace
1001	  period, print out additional per-CPU diagnostic information
1002	  regarding scheduling-clock ticks, idle state, and,
1003	  for RCU_FAST_NO_HZ kernels, idle-entry state.
1004
1005	  Say N if you are unsure.
1006
1007	  Say Y if you want to enable such diagnostics.
1008
1009config RCU_TRACE
1010	bool "Enable tracing for RCU"
1011	depends on DEBUG_KERNEL
1012	select TRACE_CLOCK
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
1020endmenu # "RCU Debugging"
1021
1022config 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
1034config 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
1044	  Note that if you want to also test saved backtraces, you will
1045	  have to enable STACKTRACE as well.
1046
1047	  Say N if you are unsure.
1048
1049config DEBUG_BLOCK_EXT_DEVT
1050        bool "Force extended block device numbers and spread them"
1051	depends on DEBUG_KERNEL
1052	depends on BLOCK
1053	default n
1054	help
1055	  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
1060	  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
1068	  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
1074	  Say N if you are unsure.
1075
1076config 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
1091config 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
1102config LKDTM
1103	tristate "Linux Kernel Dump Test Tool Module"
1104	depends on DEBUG_FS
1105	depends on BLOCK
1106	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
1115	Documentation/fault-injection/provoke-crashes.txt
1116
1117config NOTIFIER_ERROR_INJECTION
1118	tristate "Notifier error injection"
1119	depends on DEBUG_KERNEL
1120	select DEBUG_FS
1121	help
1122	  This option provides the ability to inject artificial errors to
1123	  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
1128config CPU_NOTIFIER_ERROR_INJECT
1129	tristate "CPU notifier error injection module"
1130	depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
1131	help
1132	  This option provides a kernel module that can be used to test
1133	  the error handling of the cpu notifiers by injecting artificial
1134	  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
1146
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
1152config 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
1157	  This option provides the ability to inject artificial errors to
1158	  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
1176config MEMORY_NOTIFIER_ERROR_INJECT
1177	tristate "Memory hotplug notifier error injection module"
1178	depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
1179	help
1180	  This option provides the ability to inject artificial errors to
1181	  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
1199config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1200	tristate "OF reconfig notifier error injection module"
1201	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1202	help
1203	  This option provides the ability to inject artificial errors to
1204	  OF reconfig notifier chain callbacks.  It is controlled
1205	  through debugfs interface under
1206	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1207
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
1216config FAULT_INJECTION
1217	bool "Fault-injection framework"
1218	depends on DEBUG_KERNEL
1219	help
1220	  Provide fault-injection framework.
1221	  For more details, see Documentation/fault-injection/.
1222
1223config FAILSLAB
1224	bool "Fault-injection capability for kmalloc"
1225	depends on FAULT_INJECTION
1226	depends on SLAB || SLUB
1227	help
1228	  Provide fault-injection capability for kmalloc.
1229
1230config FAIL_PAGE_ALLOC
1231	bool "Fault-injection capabilitiy for alloc_pages()"
1232	depends on FAULT_INJECTION
1233	help
1234	  Provide fault-injection capability for alloc_pages().
1235
1236config FAIL_MAKE_REQUEST
1237	bool "Fault-injection capability for disk IO"
1238	depends on FAULT_INJECTION && BLOCK
1239	help
1240	  Provide fault-injection capability for disk IO.
1241
1242config FAIL_IO_TIMEOUT
1243	bool "Fault-injection capability for faking disk interrupts"
1244	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
1253config 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
1264config FAULT_INJECTION_DEBUG_FS
1265	bool "Debugfs entries for fault-injection capabilities"
1266	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1267	help
1268	  Enable configuration of fault-injection capabilities via debugfs.
1269
1270config FAULT_INJECTION_STACKTRACE_FILTER
1271	bool "stacktrace filter for fault-injection capabilities"
1272	depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1273	depends on !X86_64
1274	select STACKTRACE
1275	select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
1276	help
1277	  Provide stacktrace filter for fault-injection capabilities
1278
1279config LATENCYTOP
1280	bool "Latency measuring infrastructure"
1281	depends on HAVE_LATENCYTOP_SUPPORT
1282	depends on DEBUG_KERNEL
1283	depends on STACKTRACE_SUPPORT
1284	depends on PROC_FS
1285	select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
1286	select KALLSYMS
1287	select KALLSYMS_ALL
1288	select STACKTRACE
1289	select SCHEDSTATS
1290	select SCHED_DEBUG
1291	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
1295source mm/Kconfig.debug
1296source kernel/trace/Kconfig
1297
1298config 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
1305config 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
1311config PROVIDE_OHCI1394_DMA_INIT
1312	bool "Remote debugging over FireWire early on boot"
1313	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.
1339
1340config 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
1351config BUILD_DOCSRC
1352	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
1360config DYNAMIC_DEBUG
1361	bool "Enable dynamic printk() support"
1362	default n
1363	depends on PRINTK
1364	depends on DEBUG_FS
1365	help
1366
1367	  Compiles debug level messages into the kernel, which would not
1368	  otherwise be available at runtime. These messages can then be
1369	  enabled/disabled based on various levels of scope - per source file,
1370	  function, module, format string, and line number. This mechanism
1371	  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.
1378
1379	  Usage:
1380
1381	  Dynamic debugging is controlled via the 'dynamic_debug/control' file,
1382	  which is contained in the 'debugfs' filesystem. Thus, the debugfs
1383	  filesystem must first be mounted before making use of this feature.
1384	  We refer the control file as: <debugfs>/dynamic_debug/control. This
1385	  file contains a list of the debug statements that can be enabled. The
1386	  format for each line of the file is:
1387
1388		filename:lineno [module]function flags format
1389
1390	  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
1394          flags : '=p' means the line is turned 'on' for printing
1395          format : the format used for the debug statement
1396
1397	  From a live system:
1398
1399		nullarbor:~ # cat <debugfs>/dynamic_debug/control
1400		# filename:lineno [module]function flags format
1401		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"
1404
1405	  Example usage:
1406
1407		// enable the message at line 1603 of file svcsock.c
1408		nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
1409						<debugfs>/dynamic_debug/control
1410
1411		// enable all the messages in file svcsock.c
1412		nullarbor:~ # echo -n 'file svcsock.c +p' >
1413						<debugfs>/dynamic_debug/control
1414
1415		// enable all the messages in the NFS server module
1416		nullarbor:~ # echo -n 'module nfsd +p' >
1417						<debugfs>/dynamic_debug/control
1418
1419		// enable all 12 messages in the function svc_process()
1420		nullarbor:~ # echo -n 'func svc_process +p' >
1421						<debugfs>/dynamic_debug/control
1422
1423		// disable all 12 messages in the function svc_process()
1424		nullarbor:~ # echo -n 'func svc_process -p' >
1425						<debugfs>/dynamic_debug/control
1426
1427	  See Documentation/dynamic-debug-howto.txt for additional information.
1428
1429config 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.
1439
1440config 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
1447config 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
1460source "samples/Kconfig"
1461
1462source "lib/Kconfig.kgdb"
1463
1464source "lib/Kconfig.kmemcheck"
1465
1466config TEST_KSTRTOX
1467	tristate "Test kstrto*() family of functions at runtime"
1468