1
2config PRINTK_TIME
3	bool "Show timing information on printks"
4	depends on PRINTK
5	help
6	  Selecting this option causes timing information to be
7	  included in printk output.  This allows you to measure
8	  the interval between kernel operations, including bootup
9	  operations.  This is useful for identifying long delays
10	  in kernel startup.
11
12config DEFAULT_MESSAGE_LOGLEVEL
13	int "Default message log level (1-7)"
14	range 1 7
15	default "4"
16	help
17	  Default log level for printk statements with no specified priority.
18
19	  This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
20	  that are auditing their logs closely may want to set it to a lower
21	  priority.
22
23config ENABLE_WARN_DEPRECATED
24	bool "Enable __deprecated logic"
25	default y
26	help
27	  Enable the __deprecated logic in the kernel build.
28	  Disable this to suppress the "warning: 'foo' is deprecated
29	  (declared at kernel/power/somefile.c:1234)" messages.
30
31config ENABLE_MUST_CHECK
32	bool "Enable __must_check logic"
33	default y
34	help
35	  Enable the __must_check logic in the kernel build.  Disable this to
36	  suppress the "warning: ignoring return value of 'foo', declared with
37	  attribute warn_unused_result" messages.
38
39config FRAME_WARN
40	int "Warn for stack frames larger than (needs gcc 4.4)"
41	range 0 8192
42	default 1024 if !64BIT
43	default 2048 if 64BIT
44	help
45	  Tell gcc to warn at build time for stack frames larger than this.
46	  Setting this too low will cause a lot of warnings.
47	  Setting it to 0 disables the warning.
48	  Requires gcc 4.4
49
50config MAGIC_SYSRQ
51	bool "Magic SysRq key"
52	depends on !UML
53	help
54	  If you say Y here, you will have some control over the system even
55	  if the system crashes for example during kernel debugging (e.g., you
56	  will be able to flush the buffer cache to disk, reboot the system
57	  immediately or dump some status information). This is accomplished
58	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
59	  also works on a serial console (on PC hardware at least), if you
60	  send a BREAK and then within 5 seconds a command keypress. The
61	  keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
62	  unless you really know what this hack does.
63
64config STRIP_ASM_SYMS
65	bool "Strip assembler-generated symbols during link"
66	default n
67	help
68	  Strip internal assembler-generated symbols during a link (symbols
69	  that look like '.Lxxx') so they don't pollute the output of
70	  get_wchan() and suchlike.
71
72config UNUSED_SYMBOLS
73	bool "Enable unused/obsolete exported symbols"
74	default y if X86
75	help
76	  Unused but exported symbols make the kernel needlessly bigger.  For
77	  that reason most of these unused exports will soon be removed.  This
78	  option is provided temporarily to provide a transition period in case
79	  some external kernel module needs one of these symbols anyway. If you
80	  encounter such a case in your module, consider if you are actually
81	  using the right API.  (rationale: since nobody in the kernel is using
82	  this in a module, there is a pretty good chance it's actually the
83	  wrong interface to use).  If you really need the symbol, please send a
84	  mail to the linux kernel mailing list mentioning the symbol and why
85	  you really need it, and what the merge plan to the mainline kernel for
86	  your module is.
87
88config DEBUG_FS
89	bool "Debug Filesystem"
90	help
91	  debugfs is a virtual file system that kernel developers use to put
92	  debugging files into.  Enable this option to be able to read and
93	  write to these files.
94
95	  For detailed documentation on the debugfs API, see
96	  Documentation/DocBook/filesystems.
97
98	  If unsure, say N.
99
100config HEADERS_CHECK
101	bool "Run 'make headers_check' when building vmlinux"
102	depends on !UML
103	help
104	  This option will extract the user-visible kernel headers whenever
105	  building the kernel, and will run basic sanity checks on them to
106	  ensure that exported files do not attempt to include files which
107	  were not exported, etc.
108
109	  If you're making modifications to header files which are
110	  relevant for userspace, say 'Y', and check the headers
111	  exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
112	  your build tree), to make sure they're suitable.
113
114config DEBUG_SECTION_MISMATCH
115	bool "Enable full Section mismatch analysis"
116	help
117	  The section mismatch analysis checks if there are illegal
118	  references from one section to another section.
119	  Linux will during link or during runtime drop some sections
120	  and any use of code/data previously in these sections will
121	  most likely result in an oops.
122	  In the code functions and variables are annotated with
123	  __init, __devinit etc. (see full list in include/linux/init.h)
124	  which results in the code/data being placed in specific sections.
125	  The section mismatch analysis is always done after a full
126	  kernel build but enabling this option will in addition
127	  do the following:
128	  - Add the option -fno-inline-functions-called-once to gcc
129	    When inlining a function annotated __init in a non-init
130	    function we would lose the section information and thus
131	    the analysis would not catch the illegal reference.
132	    This option tells gcc to inline less but will also
133	    result in a larger kernel.
134	  - Run the section mismatch analysis for each module/built-in.o
135	    When we run the section mismatch analysis on vmlinux.o we
136	    lose valueble information about where the mismatch was
137	    introduced.
138	    Running the analysis for each module/built-in.o file
139	    will tell where the mismatch happens much closer to the
140	    source. The drawback is that we will report the same
141	    mismatch at least twice.
142	  - Enable verbose reporting from modpost to help solving
143	    the section mismatches reported.
144
145config DEBUG_KERNEL
146	bool "Kernel debugging"
147	help
148	  Say Y here if you are developing drivers or trying to debug and
149	  identify kernel problems.
150
151config DEBUG_SHIRQ
152	bool "Debug shared IRQ handlers"
153	depends on DEBUG_KERNEL && GENERIC_HARDIRQS
154	help
155	  Enable this to generate a spurious interrupt as soon as a shared
156	  interrupt handler is registered, and just before one is deregistered.
157	  Drivers ought to be able to handle interrupts coming in at those
158	  points; some don't and need to be caught.
159
160config LOCKUP_DETECTOR
161	bool "Detect Hard and Soft Lockups"
162	depends on DEBUG_KERNEL && !S390
163	help
164	  Say Y here to enable the kernel to act as a watchdog to detect
165	  hard and soft lockups.
166
167	  Softlockups are bugs that cause the kernel to loop in kernel
168	  mode for more than 60 seconds, without giving other tasks a
169	  chance to run.  The current stack trace is displayed upon
170	  detection and the system will stay locked up.
171
172	  Hardlockups are bugs that cause the CPU to loop in kernel mode
173	  for more than 60 seconds, without letting other interrupts have a
174	  chance to run.  The current stack trace is displayed upon detection
175	  and the system will stay locked up.
176
177	  The overhead should be minimal.  A periodic hrtimer runs to
178	  generate interrupts and kick the watchdog task every 10-12 seconds.
179	  An NMI is generated every 60 seconds or so to check for hardlockups.
180
181config HARDLOCKUP_DETECTOR
182	def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI && \
183		 !ARCH_HAS_NMI_WATCHDOG
184
185config BOOTPARAM_HARDLOCKUP_PANIC
186	bool "Panic (Reboot) On Hard Lockups"
187	depends on LOCKUP_DETECTOR
188	help
189	  Say Y here to enable the kernel to panic on "hard lockups",
190	  which are bugs that cause the kernel to loop in kernel
191	  mode with interrupts disabled for more than 60 seconds.
192
193	  Say N if unsure.
194
195config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
196	int
197	depends on LOCKUP_DETECTOR
198	range 0 1
199	default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
200	default 1 if BOOTPARAM_HARDLOCKUP_PANIC
201
202config BOOTPARAM_SOFTLOCKUP_PANIC
203	bool "Panic (Reboot) On Soft Lockups"
204	depends on LOCKUP_DETECTOR
205	help
206	  Say Y here to enable the kernel to panic on "soft lockups",
207	  which are bugs that cause the kernel to loop in kernel
208	  mode for more than 60 seconds, without giving other tasks a
209	  chance to run.
210
211	  The panic can be used in combination with panic_timeout,
212	  to cause the system to reboot automatically after a
213	  lockup has been detected. This feature is useful for
214	  high-availability systems that have uptime guarantees and
215	  where a lockup must be resolved ASAP.
216
217	  Say N if unsure.
218
219config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
220	int
221	depends on LOCKUP_DETECTOR
222	range 0 1
223	default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
224	default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
225
226config DETECT_HUNG_TASK
227	bool "Detect Hung Tasks"
228	depends on DEBUG_KERNEL
229	default DETECT_SOFTLOCKUP
230	help
231	  Say Y here to enable the kernel to detect "hung tasks",
232	  which are bugs that cause the task to be stuck in
233	  uninterruptible "D" state indefinitiley.
234
235	  When a hung task is detected, the kernel will print the
236	  current stack trace (which you should report), but the
237	  task will stay in uninterruptible state. If lockdep is
238	  enabled then all held locks will also be reported. This
239	  feature has negligible overhead.
240
241config BOOTPARAM_HUNG_TASK_PANIC
242	bool "Panic (Reboot) On Hung Tasks"
243	depends on DETECT_HUNG_TASK
244	help
245	  Say Y here to enable the kernel to panic on "hung tasks",
246	  which are bugs that cause the kernel to leave a task stuck
247	  in uninterruptible "D" state.
248
249	  The panic can be used in combination with panic_timeout,
250	  to cause the system to reboot automatically after a
251	  hung task has been detected. This feature is useful for
252	  high-availability systems that have uptime guarantees and
253	  where a hung tasks must be resolved ASAP.
254
255	  Say N if unsure.
256
257config BOOTPARAM_HUNG_TASK_PANIC_VALUE
258	int
259	depends on DETECT_HUNG_TASK
260	range 0 1
261	default 0 if !BOOTPARAM_HUNG_TASK_PANIC
262	default 1 if BOOTPARAM_HUNG_TASK_PANIC
263
264config SCHED_DEBUG
265	bool "Collect scheduler debugging info"
266	depends on DEBUG_KERNEL && PROC_FS
267	default y
268	help
269	  If you say Y here, the /proc/sched_debug file will be provided
270	  that can help debug the scheduler. The runtime overhead of this
271	  option is minimal.
272
273config SCHEDSTATS
274	bool "Collect scheduler statistics"
275	depends on DEBUG_KERNEL && PROC_FS
276	help
277	  If you say Y here, additional code will be inserted into the
278	  scheduler and related routines to collect statistics about
279	  scheduler behavior and provide them in /proc/schedstat.  These
280	  stats may be useful for both tuning and debugging the scheduler
281	  If you aren't debugging the scheduler or trying to tune a specific
282	  application, you can say N to avoid the very slight overhead
283	  this adds.
284
285config TIMER_STATS
286	bool "Collect kernel timers statistics"
287	depends on DEBUG_KERNEL && PROC_FS
288	help
289	  If you say Y here, additional code will be inserted into the
290	  timer routines to collect statistics about kernel timers being
291	  reprogrammed. The statistics can be read from /proc/timer_stats.
292	  The statistics collection is started by writing 1 to /proc/timer_stats,
293	  writing 0 stops it. This feature is useful to collect information
294	  about timer usage patterns in kernel and userspace. This feature
295	  is lightweight if enabled in the kernel config but not activated
296	  (it defaults to deactivated on bootup and will only be activated
297	  if some application like powertop activates it explicitly).
298
299config DEBUG_OBJECTS
300	bool "Debug object operations"
301	depends on DEBUG_KERNEL
302	help
303	  If you say Y here, additional code will be inserted into the
304	  kernel to track the life time of various objects and validate
305	  the operations on those objects.
306
307config DEBUG_OBJECTS_SELFTEST
308	bool "Debug objects selftest"
309	depends on DEBUG_OBJECTS
310	help
311	  This enables the selftest of the object debug code.
312
313config DEBUG_OBJECTS_FREE
314	bool "Debug objects in freed memory"
315	depends on DEBUG_OBJECTS
316	help
317	  This enables checks whether a k/v free operation frees an area
318	  which contains an object which has not been deactivated
319	  properly. This can make kmalloc/kfree-intensive workloads
320	  much slower.
321
322config DEBUG_OBJECTS_TIMERS
323	bool "Debug timer objects"
324	depends on DEBUG_OBJECTS
325	help
326	  If you say Y here, additional code will be inserted into the
327	  timer routines to track the life time of timer objects and
328	  validate the timer operations.
329
330config DEBUG_OBJECTS_WORK
331	bool "Debug work objects"
332	depends on DEBUG_OBJECTS
333	help
334	  If you say Y here, additional code will be inserted into the
335	  work queue routines to track the life time of work objects and
336	  validate the work operations.
337
338config DEBUG_OBJECTS_RCU_HEAD
339	bool "Debug RCU callbacks objects"
340	depends on DEBUG_OBJECTS && PREEMPT
341	help
342	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
343
344config DEBUG_OBJECTS_PERCPU_COUNTER
345	bool "Debug percpu counter objects"
346	depends on DEBUG_OBJECTS
347	help
348	  If you say Y here, additional code will be inserted into the
349	  percpu counter routines to track the life time of percpu counter
350	  objects and validate the percpu counter operations.
351
352config DEBUG_OBJECTS_ENABLE_DEFAULT
353	int "debug_objects bootup default value (0-1)"
354        range 0 1
355        default "1"
356        depends on DEBUG_OBJECTS
357        help
358          Debug objects boot parameter default value
359
360config DEBUG_SLAB
361	bool "Debug slab memory allocations"
362	depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
363	help
364	  Say Y here to have the kernel do limited verification on memory
365	  allocation as well as poisoning memory on free to catch use of freed
366	  memory. This can make kmalloc/kfree-intensive workloads much slower.
367
368config DEBUG_SLAB_LEAK
369	bool "Memory leak debugging"
370	depends on DEBUG_SLAB
371
372config SLUB_DEBUG_ON
373	bool "SLUB debugging on by default"
374	depends on SLUB && SLUB_DEBUG && !KMEMCHECK
375	default n
376	help
377	  Boot with debugging on by default. SLUB boots by default with
378	  the runtime debug capabilities switched off. Enabling this is
379	  equivalent to specifying the "slub_debug" parameter on boot.
380	  There is no support for more fine grained debug control like
381	  possible with slub_debug=xxx. SLUB debugging may be switched
382	  off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
383	  "slub_debug=-".
384
385config SLUB_STATS
386	default n
387	bool "Enable SLUB performance statistics"
388	depends on SLUB && SYSFS
389	help
390	  SLUB statistics are useful to debug SLUBs allocation behavior in
391	  order find ways to optimize the allocator. This should never be
392	  enabled for production use since keeping statistics slows down
393	  the allocator by a few percentage points. The slabinfo command
394	  supports the determination of the most active slabs to figure
395	  out which slabs are relevant to a particular load.
396	  Try running: slabinfo -DA
397
398config DEBUG_KMEMLEAK
399	bool "Kernel memory leak detector"
400	depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
401		(X86 || ARM || PPC || S390 || SPARC64 || SUPERH || MICROBLAZE || TILE)
402
403	select DEBUG_FS if SYSFS
404	select STACKTRACE if STACKTRACE_SUPPORT
405	select KALLSYMS
406	select CRC32
407	help
408	  Say Y here if you want to enable the memory leak
409	  detector. The memory allocation/freeing is traced in a way
410	  similar to the Boehm's conservative garbage collector, the
411	  difference being that the orphan objects are not freed but
412	  only shown in /sys/kernel/debug/kmemleak. Enabling this
413	  feature will introduce an overhead to memory
414	  allocations. See Documentation/kmemleak.txt for more
415	  details.
416
417	  Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
418	  of finding leaks due to the slab objects poisoning.
419
420	  In order to access the kmemleak file, debugfs needs to be
421	  mounted (usually at /sys/kernel/debug).
422
423config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
424	int "Maximum kmemleak early log entries"
425	depends on DEBUG_KMEMLEAK
426	range 200 40000
427	default 400
428	help
429	  Kmemleak must track all the memory allocations to avoid
430	  reporting false positives. Since memory may be allocated or
431	  freed before kmemleak is initialised, an early log buffer is
432	  used to store these actions. If kmemleak reports "early log
433	  buffer exceeded", please increase this value.
434
435config DEBUG_KMEMLEAK_TEST
436	tristate "Simple test for the kernel memory leak detector"
437	depends on DEBUG_KMEMLEAK && m
438	help
439	  This option enables a module that explicitly leaks memory.
440
441	  If unsure, say N.
442
443config DEBUG_KMEMLEAK_DEFAULT_OFF
444	bool "Default kmemleak to off"
445	depends on DEBUG_KMEMLEAK
446	help
447	  Say Y here to disable kmemleak by default. It can then be enabled
448	  on the command line via kmemleak=on.
449
450config DEBUG_PREEMPT
451	bool "Debug preemptible kernel"
452	depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
453	default y
454	help
455	  If you say Y here then the kernel will use a debug variant of the
456	  commonly used smp_processor_id() function and will print warnings
457	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
458	  will detect preemption count underflows.
459
460config DEBUG_RT_MUTEXES
461	bool "RT Mutex debugging, deadlock detection"
462	depends on DEBUG_KERNEL && RT_MUTEXES
463	help
464	 This allows rt mutex semantics violations and rt mutex related
465	 deadlocks (lockups) to be detected and reported automatically.
466
467config DEBUG_PI_LIST
468	bool
469	default y
470	depends on DEBUG_RT_MUTEXES
471
472config RT_MUTEX_TESTER
473	bool "Built-in scriptable tester for rt-mutexes"
474	depends on DEBUG_KERNEL && RT_MUTEXES
475	help
476	  This option enables a rt-mutex tester.
477
478config DEBUG_SPINLOCK
479	bool "Spinlock and rw-lock debugging: basic checks"
480	depends on DEBUG_KERNEL
481	help
482	  Say Y here and build SMP to catch missing spinlock initialization
483	  and certain other kinds of spinlock errors commonly made.  This is
484	  best used in conjunction with the NMI watchdog so that spinlock
485	  deadlocks are also debuggable.
486
487config DEBUG_MUTEXES
488	bool "Mutex debugging: basic checks"
489	depends on DEBUG_KERNEL
490	help
491	 This feature allows mutex semantics violations to be detected and
492	 reported.
493
494config DEBUG_LOCK_ALLOC
495	bool "Lock debugging: detect incorrect freeing of live locks"
496	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
497	select DEBUG_SPINLOCK
498	select DEBUG_MUTEXES
499	select LOCKDEP
500	help
501	 This feature will check whether any held lock (spinlock, rwlock,
502	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
503	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
504	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
505	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
506	 held during task exit.
507
508config PROVE_LOCKING
509	bool "Lock debugging: prove locking correctness"
510	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
511	select LOCKDEP
512	select DEBUG_SPINLOCK
513	select DEBUG_MUTEXES
514	select DEBUG_LOCK_ALLOC
515	select TRACE_IRQFLAGS
516	default n
517	help
518	 This feature enables the kernel to prove that all locking
519	 that occurs in the kernel runtime is mathematically
520	 correct: that under no circumstance could an arbitrary (and
521	 not yet triggered) combination of observed locking
522	 sequences (on an arbitrary number of CPUs, running an
523	 arbitrary number of tasks and interrupt contexts) cause a
524	 deadlock.
525
526	 In short, this feature enables the kernel to report locking
527	 related deadlocks before they actually occur.
528
529	 The proof does not depend on how hard and complex a
530	 deadlock scenario would be to trigger: how many
531	 participant CPUs, tasks and irq-contexts would be needed
532	 for it to trigger. The proof also does not depend on
533	 timing: if a race and a resulting deadlock is possible
534	 theoretically (no matter how unlikely the race scenario
535	 is), it will be proven so and will immediately be
536	 reported by the kernel (once the event is observed that
537	 makes the deadlock theoretically possible).
538
539	 If a deadlock is impossible (i.e. the locking rules, as
540	 observed by the kernel, are mathematically correct), the
541	 kernel reports nothing.
542
543	 NOTE: this feature can also be enabled for rwlocks, mutexes
544	 and rwsems - in which case all dependencies between these
545	 different locking variants are observed and mapped too, and
546	 the proof of observed correctness is also maintained for an
547	 arbitrary combination of these separate locking variants.
548
549	 For more details, see Documentation/lockdep-design.txt.
550
551config PROVE_RCU
552	bool "RCU debugging: prove RCU correctness"
553	depends on PROVE_LOCKING
554	default n
555	help
556	 This feature enables lockdep extensions that check for correct
557	 use of RCU APIs.  This is currently under development.  Say Y
558	 if you want to debug RCU usage or help work on the PROVE_RCU
559	 feature.
560
561	 Say N if you are unsure.
562
563config PROVE_RCU_REPEATEDLY
564	bool "RCU debugging: don't disable PROVE_RCU on first splat"
565	depends on PROVE_RCU
566	default n
567	help
568	 By itself, PROVE_RCU will disable checking upon issuing the
569	 first warning (or "splat").  This feature prevents such
570	 disabling, allowing multiple RCU-lockdep warnings to be printed
571	 on a single reboot.
572
573	 Say Y to allow multiple RCU-lockdep warnings per boot.
574
575	 Say N if you are unsure.
576
577config SPARSE_RCU_POINTER
578	bool "RCU debugging: sparse-based checks for pointer usage"
579	default n
580	help
581	 This feature enables the __rcu sparse annotation for
582	 RCU-protected pointers.  This annotation will cause sparse
583	 to flag any non-RCU used of annotated pointers.  This can be
584	 helpful when debugging RCU usage.  Please note that this feature
585	 is not intended to enforce code cleanliness; it is instead merely
586	 a debugging aid.
587
588	 Say Y to make sparse flag questionable use of RCU-protected pointers
589
590	 Say N if you are unsure.
591
592config LOCKDEP
593	bool
594	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
595	select STACKTRACE
596	select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
597	select KALLSYMS
598	select KALLSYMS_ALL
599
600config LOCK_STAT
601	bool "Lock usage statistics"
602	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
603	select LOCKDEP
604	select DEBUG_SPINLOCK
605	select DEBUG_MUTEXES
606	select DEBUG_LOCK_ALLOC
607	default n
608	help
609	 This feature enables tracking lock contention points
610
611	 For more details, see Documentation/lockstat.txt
612
613	 This also enables lock events required by "perf lock",
614	 subcommand of perf.
615	 If you want to use "perf lock", you also need to turn on
616	 CONFIG_EVENT_TRACING.
617
618	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
619	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
620
621config DEBUG_LOCKDEP
622	bool "Lock dependency engine debugging"
623	depends on DEBUG_KERNEL && LOCKDEP
624	help
625	  If you say Y here, the lock dependency engine will do
626	  additional runtime checks to debug itself, at the price
627	  of more runtime overhead.
628
629config TRACE_IRQFLAGS
630	bool
631	help
632	  Enables hooks to interrupt enabling and disabling for
633	  either tracing or lock debugging.
634
635config DEBUG_SPINLOCK_SLEEP
636	bool "Spinlock debugging: sleep-inside-spinlock checking"
637	depends on DEBUG_KERNEL
638	help
639	  If you say Y here, various routines which may sleep will become very
640	  noisy if they are called with a spinlock held.
641
642config DEBUG_LOCKING_API_SELFTESTS
643	bool "Locking API boot-time self-tests"
644	depends on DEBUG_KERNEL
645	help
646	  Say Y here if you want the kernel to run a short self-test during
647	  bootup. The self-test checks whether common types of locking bugs
648	  are detected by debugging mechanisms or not. (if you disable
649	  lock debugging then those bugs wont be detected of course.)
650	  The following locking APIs are covered: spinlocks, rwlocks,
651	  mutexes and rwsems.
652
653config STACKTRACE
654	bool
655	depends on STACKTRACE_SUPPORT
656
657config DEBUG_KOBJECT
658	bool "kobject debugging"
659	depends on DEBUG_KERNEL
660	help
661	  If you say Y here, some extra kobject debugging messages will be sent
662	  to the syslog.
663
664config DEBUG_HIGHMEM
665	bool "Highmem debugging"
666	depends on DEBUG_KERNEL && HIGHMEM
667	help
668	  This options enables addition error checking for high memory systems.
669	  Disable for production systems.
670
671config DEBUG_BUGVERBOSE
672	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
673	depends on BUG
674	depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
675		   FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
676	default y
677	help
678	  Say Y here to make BUG() panics output the file name and line number
679	  of the BUG call as well as the EIP and oops trace.  This aids
680	  debugging but costs about 70-100K of memory.
681
682config DEBUG_INFO
683	bool "Compile the kernel with debug info"
684	depends on DEBUG_KERNEL
685	help
686          If you say Y here the resulting kernel image will include
687	  debugging info resulting in a larger kernel image.
688	  This adds debug symbols to the kernel and modules (gcc -g), and
689	  is needed if you intend to use kernel crashdump or binary object
690	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
691	  Say Y here only if you plan to debug the kernel.
692
693	  If unsure, say N.
694
695config DEBUG_INFO_REDUCED
696	bool "Reduce debugging information"
697	depends on DEBUG_INFO
698	help
699	  If you say Y here gcc is instructed to generate less debugging
700	  information for structure types. This means that tools that
701	  need full debugging information (like kgdb or systemtap) won't
702	  be happy. But if you merely need debugging information to
703	  resolve line numbers there is no loss. Advantage is that
704	  build directory object sizes shrink dramatically over a full
705	  DEBUG_INFO build and compile times are reduced too.
706	  Only works with newer gcc versions.
707
708config DEBUG_VM
709	bool "Debug VM"
710	depends on DEBUG_KERNEL
711	help
712	  Enable this to turn on extended checks in the virtual-memory system
713          that may impact performance.
714
715	  If unsure, say N.
716
717config DEBUG_VIRTUAL
718	bool "Debug VM translations"
719	depends on DEBUG_KERNEL && X86
720	help
721	  Enable some costly sanity checks in virtual to page code. This can
722	  catch mistakes with virt_to_page() and friends.
723
724	  If unsure, say N.
725
726config DEBUG_NOMMU_REGIONS
727	bool "Debug the global anon/private NOMMU mapping region tree"
728	depends on DEBUG_KERNEL && !MMU
729	help
730	  This option causes the global tree of anonymous and private mapping
731	  regions to be regularly checked for invalid topology.
732
733config DEBUG_WRITECOUNT
734	bool "Debug filesystem writers count"
735	depends on DEBUG_KERNEL
736	help
737	  Enable this to catch wrong use of the writers count in struct
738	  vfsmount.  This will increase the size of each file struct by
739	  32 bits.
740
741	  If unsure, say N.
742
743config DEBUG_MEMORY_INIT
744	bool "Debug memory initialisation" if EXPERT
745	default !EXPERT
746	help
747	  Enable this for additional checks during memory initialisation.
748	  The sanity checks verify aspects of the VM such as the memory model
749	  and other information provided by the architecture. Verbose
750	  information will be printed at KERN_DEBUG loglevel depending
751	  on the mminit_loglevel= command-line option.
752
753	  If unsure, say Y
754
755config DEBUG_LIST
756	bool "Debug linked list manipulation"
757	depends on DEBUG_KERNEL
758	help
759	  Enable this to turn on extended checks in the linked-list
760	  walking routines.
761
762	  If unsure, say N.
763
764config TEST_LIST_SORT
765	bool "Linked list sorting test"
766	depends on DEBUG_KERNEL
767	help
768	  Enable this to turn on 'list_sort()' function test. This test is
769	  executed only once during system boot, so affects only boot time.
770
771	  If unsure, say N.
772
773config DEBUG_SG
774	bool "Debug SG table operations"
775	depends on DEBUG_KERNEL
776	help
777	  Enable this to turn on checks on scatter-gather tables. This can
778	  help find problems with drivers that do not properly initialize
779	  their sg tables.
780
781	  If unsure, say N.
782
783config DEBUG_NOTIFIERS
784	bool "Debug notifier call chains"
785	depends on DEBUG_KERNEL
786	help
787	  Enable this to turn on sanity checking for notifier call chains.
788	  This is most useful for kernel developers to make sure that
789	  modules properly unregister themselves from notifier chains.
790	  This is a relatively cheap check but if you care about maximum
791	  performance, say N.
792
793config DEBUG_CREDENTIALS
794	bool "Debug credential management"
795	depends on DEBUG_KERNEL
796	help
797	  Enable this to turn on some debug checking for credential
798	  management.  The additional code keeps track of the number of
799	  pointers from task_structs to any given cred struct, and checks to
800	  see that this number never exceeds the usage count of the cred
801	  struct.
802
803	  Furthermore, if SELinux is enabled, this also checks that the
804	  security pointer in the cred struct is never seen to be invalid.
805
806	  If unsure, say N.
807
808#
809# Select this config option from the architecture Kconfig, if it
810# it is preferred to always offer frame pointers as a config
811# option on the architecture (regardless of KERNEL_DEBUG):
812#
813config ARCH_WANT_FRAME_POINTERS
814	bool
815	help
816
817config FRAME_POINTER
818	bool "Compile the kernel with frame pointers"
819	depends on DEBUG_KERNEL && \
820		(CRIS || M68K || FRV || UML || \
821		 AVR32 || SUPERH || BLACKFIN || MN10300) || \
822		ARCH_WANT_FRAME_POINTERS
823	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
824	help
825	  If you say Y here the resulting kernel image will be slightly
826	  larger and slower, but it gives very useful debugging information
827	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
828
829config BOOT_PRINTK_DELAY
830	bool "Delay each boot printk message by N milliseconds"
831	depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
832	help
833	  This build option allows you to read kernel boot messages
834	  by inserting a short delay after each one.  The delay is
835	  specified in milliseconds on the kernel command line,
836	  using "boot_delay=N".
837
838	  It is likely that you would also need to use "lpj=M" to preset
839	  the "loops per jiffie" value.
840	  See a previous boot log for the "lpj" value to use for your
841	  system, and then set "lpj=M" before setting "boot_delay=N".
842	  NOTE:  Using this option may adversely affect SMP systems.
843	  I.e., processors other than the first one may not boot up.
844	  BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
845	  what it believes to be lockup conditions.
846
847config RCU_TORTURE_TEST
848	tristate "torture tests for RCU"
849	depends on DEBUG_KERNEL
850	default n
851	help
852	  This option provides a kernel module that runs torture tests
853	  on the RCU infrastructure.  The kernel module may be built
854	  after the fact on the running kernel to be tested, if desired.
855
856	  Say Y here if you want RCU torture tests to be built into
857	  the kernel.
858	  Say M if you want the RCU torture tests to build as a module.
859	  Say N if you are unsure.
860
861config RCU_TORTURE_TEST_RUNNABLE
862	bool "torture tests for RCU runnable by default"
863	depends on RCU_TORTURE_TEST = y
864	default n
865	help
866	  This option provides a way to build the RCU torture tests
867	  directly into the kernel without them starting up at boot
868	  time.  You can use /proc/sys/kernel/rcutorture_runnable
869	  to manually override this setting.  This /proc file is
870	  available only when the RCU torture tests have been built
871	  into the kernel.
872
873	  Say Y here if you want the RCU torture tests to start during
874	  boot (you probably don't).
875	  Say N here if you want the RCU torture tests to start only
876	  after being manually enabled via /proc.
877
878config RCU_CPU_STALL_DETECTOR
879	bool "Check for stalled CPUs delaying RCU grace periods"
880	depends on TREE_RCU || TREE_PREEMPT_RCU
881	default y
882	help
883	  This option causes RCU to printk information on which
884	  CPUs are delaying the current grace period, but only when
885	  the grace period extends for excessive time periods.
886
887	  Say N if you want to disable such checks.
888
889	  Say Y if you are unsure.
890
891config RCU_CPU_STALL_TIMEOUT
892	int "RCU CPU stall timeout in seconds"
893	depends on RCU_CPU_STALL_DETECTOR
894	range 3 300
895	default 60
896	help
897	  If a given RCU grace period extends more than the specified
898	  number of seconds, a CPU stall warning is printed.  If the
899	  RCU grace period persists, additional CPU stall warnings are
900	  printed at more widely spaced intervals.
901
902config RCU_CPU_STALL_DETECTOR_RUNNABLE
903	bool "RCU CPU stall checking starts automatically at boot"
904	depends on RCU_CPU_STALL_DETECTOR
905	default y
906	help
907	  If set, start checking for RCU CPU stalls immediately on
908	  boot.  Otherwise, RCU CPU stall checking must be manually
909	  enabled.
910
911	  Say Y if you are unsure.
912
913	  Say N if you wish to suppress RCU CPU stall checking during boot.
914
915config RCU_CPU_STALL_VERBOSE
916	bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
917	depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU
918	default y
919	help
920	  This option causes RCU to printk detailed per-task information
921	  for any tasks that are stalling the current RCU grace period.
922
923	  Say N if you are unsure.
924
925	  Say Y if you want to enable such checks.
926
927config KPROBES_SANITY_TEST
928	bool "Kprobes sanity tests"
929	depends on DEBUG_KERNEL
930	depends on KPROBES
931	default n
932	help
933	  This option provides for testing basic kprobes functionality on
934	  boot. A sample kprobe, jprobe and kretprobe are inserted and
935	  verified for functionality.
936
937	  Say N if you are unsure.
938
939config BACKTRACE_SELF_TEST
940	tristate "Self test for the backtrace code"
941	depends on DEBUG_KERNEL
942	default n
943	help
944	  This option provides a kernel module that can be used to test
945	  the kernel stack backtrace code. This option is not useful
946	  for distributions or general kernels, but only for kernel
947	  developers working on architecture code.
948
949	  Note that if you want to also test saved backtraces, you will
950	  have to enable STACKTRACE as well.
951
952	  Say N if you are unsure.
953
954config DEBUG_BLOCK_EXT_DEVT
955        bool "Force extended block device numbers and spread them"
956	depends on DEBUG_KERNEL
957	depends on BLOCK
958	default n
959	help
960	  BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
961	  SOME DISTRIBUTIONS.  DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
962	  YOU ARE DOING.  Distros, please enable this and fix whatever
963	  is broken.
964
965	  Conventionally, block device numbers are allocated from
966	  predetermined contiguous area.  However, extended block area
967	  may introduce non-contiguous block device numbers.  This
968	  option forces most block device numbers to be allocated from
969	  the extended space and spreads them to discover kernel or
970	  userland code paths which assume predetermined contiguous
971	  device number allocation.
972
973	  Note that turning on this debug option shuffles all the
974	  device numbers for all IDE and SCSI devices including libata
975	  ones, so root partition specified using device number
976	  directly (via rdev or root=MAJ:MIN) won't work anymore.
977	  Textual device names (root=/dev/sdXn) will continue to work.
978
979	  Say N if you are unsure.
980
981config DEBUG_FORCE_WEAK_PER_CPU
982	bool "Force weak per-cpu definitions"
983	depends on DEBUG_KERNEL
984	help
985	  s390 and alpha require percpu variables in modules to be
986	  defined weak to work around addressing range issue which
987	  puts the following two restrictions on percpu variable
988	  definitions.
989
990	  1. percpu symbols must be unique whether static or not
991	  2. percpu variables can't be defined inside a function
992
993	  To ensure that generic code follows the above rules, this
994	  option forces all percpu variables to be defined as weak.
995
996config LKDTM
997	tristate "Linux Kernel Dump Test Tool Module"
998	depends on DEBUG_FS
999	depends on BLOCK
1000	default n
1001	help
1002	This module enables testing of the different dumping mechanisms by
1003	inducing system failures at predefined crash points.
1004	If you don't need it: say N
1005	Choose M here to compile this code as a module. The module will be
1006	called lkdtm.
1007
1008	Documentation on how to use the module can be found in
1009	Documentation/fault-injection/provoke-crashes.txt
1010
1011config CPU_NOTIFIER_ERROR_INJECT
1012	tristate "CPU notifier error injection module"
1013	depends on HOTPLUG_CPU && DEBUG_KERNEL
1014	help
1015	  This option provides a kernel module that can be used to test
1016	  the error handling of the cpu notifiers
1017
1018	  To compile this code as a module, choose M here: the module will
1019	  be called cpu-notifier-error-inject.
1020
1021	  If unsure, say N.
1022
1023config FAULT_INJECTION
1024	bool "Fault-injection framework"
1025	depends on DEBUG_KERNEL
1026	help
1027	  Provide fault-injection framework.
1028	  For more details, see Documentation/fault-injection/.
1029
1030config FAILSLAB
1031	bool "Fault-injection capability for kmalloc"
1032	depends on FAULT_INJECTION
1033	depends on SLAB || SLUB
1034	help
1035	  Provide fault-injection capability for kmalloc.
1036
1037config FAIL_PAGE_ALLOC
1038	bool "Fault-injection capabilitiy for alloc_pages()"
1039	depends on FAULT_INJECTION
1040	help
1041	  Provide fault-injection capability for alloc_pages().
1042
1043config FAIL_MAKE_REQUEST
1044	bool "Fault-injection capability for disk IO"
1045	depends on FAULT_INJECTION && BLOCK
1046	help
1047	  Provide fault-injection capability for disk IO.
1048
1049config FAIL_IO_TIMEOUT
1050	bool "Fault-injection capability for faking disk interrupts"
1051	depends on FAULT_INJECTION && BLOCK
1052	help
1053	  Provide fault-injection capability on end IO handling. This
1054	  will make the block layer "forget" an interrupt as configured,
1055	  thus exercising the error handling.
1056
1057	  Only works with drivers that use the generic timeout handling,
1058	  for others it wont do anything.
1059
1060config FAULT_INJECTION_DEBUG_FS
1061	bool "Debugfs entries for fault-injection capabilities"
1062	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1063	help
1064	  Enable configuration of fault-injection capabilities via debugfs.
1065
1066config FAULT_INJECTION_STACKTRACE_FILTER
1067	bool "stacktrace filter for fault-injection capabilities"
1068	depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1069	depends on !X86_64
1070	select STACKTRACE
1071	select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE
1072	help
1073	  Provide stacktrace filter for fault-injection capabilities
1074
1075config LATENCYTOP
1076	bool "Latency measuring infrastructure"
1077	depends on HAVE_LATENCYTOP_SUPPORT
1078	depends on DEBUG_KERNEL
1079	depends on STACKTRACE_SUPPORT
1080	depends on PROC_FS
1081	select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE
1082	select KALLSYMS
1083	select KALLSYMS_ALL
1084	select STACKTRACE
1085	select SCHEDSTATS
1086	select SCHED_DEBUG
1087	help
1088	  Enable this option if you want to use the LatencyTOP tool
1089	  to find out which userspace is blocking on what kernel operations.
1090
1091config SYSCTL_SYSCALL_CHECK
1092	bool "Sysctl checks"
1093	depends on SYSCTL
1094	---help---
1095	  sys_sysctl uses binary paths that have been found challenging
1096	  to properly maintain and use. This enables checks that help
1097	  you to keep things correct.
1098
1099source mm/Kconfig.debug
1100source kernel/trace/Kconfig
1101
1102config PROVIDE_OHCI1394_DMA_INIT
1103	bool "Remote debugging over FireWire early on boot"
1104	depends on PCI && X86
1105	help
1106	  If you want to debug problems which hang or crash the kernel early
1107	  on boot and the crashing machine has a FireWire port, you can use
1108	  this feature to remotely access the memory of the crashed machine
1109	  over FireWire. This employs remote DMA as part of the OHCI1394
1110	  specification which is now the standard for FireWire controllers.
1111
1112	  With remote DMA, you can monitor the printk buffer remotely using
1113	  firescope and access all memory below 4GB using fireproxy from gdb.
1114	  Even controlling a kernel debugger is possible using remote DMA.
1115
1116	  Usage:
1117
1118	  If ohci1394_dma=early is used as boot parameter, it will initialize
1119	  all OHCI1394 controllers which are found in the PCI config space.
1120
1121	  As all changes to the FireWire bus such as enabling and disabling
1122	  devices cause a bus reset and thereby disable remote DMA for all
1123	  devices, be sure to have the cable plugged and FireWire enabled on
1124	  the debugging host before booting the debug target for debugging.
1125
1126	  This code (~1k) is freed after boot. By then, the firewire stack
1127	  in charge of the OHCI-1394 controllers should be used instead.
1128
1129	  See Documentation/debugging-via-ohci1394.txt for more information.
1130
1131config FIREWIRE_OHCI_REMOTE_DMA
1132	bool "Remote debugging over FireWire with firewire-ohci"
1133	depends on FIREWIRE_OHCI
1134	help
1135	  This option lets you use the FireWire bus for remote debugging
1136	  with help of the firewire-ohci driver. It enables unfiltered
1137	  remote DMA in firewire-ohci.
1138	  See Documentation/debugging-via-ohci1394.txt for more information.
1139
1140	  If unsure, say N.
1141
1142config BUILD_DOCSRC
1143	bool "Build targets in Documentation/ tree"
1144	depends on HEADERS_CHECK
1145	help
1146	  This option attempts to build objects from the source files in the
1147	  kernel Documentation/ tree.
1148
1149	  Say N if you are unsure.
1150
1151config DYNAMIC_DEBUG
1152	bool "Enable dynamic printk() support"
1153	default n
1154	depends on PRINTK
1155	depends on DEBUG_FS
1156	help
1157
1158	  Compiles debug level messages into the kernel, which would not
1159	  otherwise be available at runtime. These messages can then be
1160	  enabled/disabled based on various levels of scope - per source file,
1161	  function, module, format string, and line number. This mechanism
1162	  implicitly enables all pr_debug() and dev_dbg() calls. The impact of
1163	  this compile option is a larger kernel text size of about 2%.
1164
1165	  Usage:
1166
1167	  Dynamic debugging is controlled via the 'dynamic_debug/control' file,
1168	  which is contained in the 'debugfs' filesystem. Thus, the debugfs
1169	  filesystem must first be mounted before making use of this feature.
1170	  We refer the control file as: <debugfs>/dynamic_debug/control. This
1171	  file contains a list of the debug statements that can be enabled. The
1172	  format for each line of the file is:
1173
1174		filename:lineno [module]function flags format
1175
1176	  filename : source file of the debug statement
1177	  lineno : line number of the debug statement
1178	  module : module that contains the debug statement
1179	  function : function that contains the debug statement
1180          flags : 'p' means the line is turned 'on' for printing
1181          format : the format used for the debug statement
1182
1183	  From a live system:
1184
1185		nullarbor:~ # cat <debugfs>/dynamic_debug/control
1186		# filename:lineno [module]function flags format
1187		fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
1188		fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
1189		fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
1190
1191	  Example usage:
1192
1193		// enable the message at line 1603 of file svcsock.c
1194		nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
1195						<debugfs>/dynamic_debug/control
1196
1197		// enable all the messages in file svcsock.c
1198		nullarbor:~ # echo -n 'file svcsock.c +p' >
1199						<debugfs>/dynamic_debug/control
1200
1201		// enable all the messages in the NFS server module
1202		nullarbor:~ # echo -n 'module nfsd +p' >
1203						<debugfs>/dynamic_debug/control
1204
1205		// enable all 12 messages in the function svc_process()
1206		nullarbor:~ # echo -n 'func svc_process +p' >
1207						<debugfs>/dynamic_debug/control
1208
1209		// disable all 12 messages in the function svc_process()
1210		nullarbor:~ # echo -n 'func svc_process -p' >
1211						<debugfs>/dynamic_debug/control
1212
1213	  See Documentation/dynamic-debug-howto.txt for additional information.
1214
1215config DMA_API_DEBUG
1216	bool "Enable debugging of DMA-API usage"
1217	depends on HAVE_DMA_API_DEBUG
1218	help
1219	  Enable this option to debug the use of the DMA API by device drivers.
1220	  With this option you will be able to detect common bugs in device
1221	  drivers like double-freeing of DMA mappings or freeing mappings that
1222	  were never allocated.
1223	  This option causes a performance degredation.  Use only if you want
1224	  to debug device drivers. If unsure, say N.
1225
1226config ATOMIC64_SELFTEST
1227	bool "Perform an atomic64_t self-test at boot"
1228	help
1229	  Enable this option to test the atomic64_t functions at boot.
1230
1231	  If unsure, say N.
1232
1233config ASYNC_RAID6_TEST
1234	tristate "Self test for hardware accelerated raid6 recovery"
1235	depends on ASYNC_RAID6_RECOV
1236	select ASYNC_MEMCPY
1237	---help---
1238	  This is a one-shot self test that permutes through the
1239	  recovery of all the possible two disk failure scenarios for a
1240	  N-disk array.  Recovery is performed with the asynchronous
1241	  raid6 recovery routines, and will optionally use an offload
1242	  engine if one is available.
1243
1244	  If unsure, say N.
1245
1246source "samples/Kconfig"
1247
1248source "lib/Kconfig.kgdb"
1249
1250source "lib/Kconfig.kmemcheck"
1251
1252config TEST_KSTRTOX
1253	tristate "Test kstrto*() family of functions at runtime"
1254