| blob | 69a32664c289692576677a48d5daacca69212752 |
2 config 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.
12 config ENABLE_WARN_DEPRECATED
13 bool "Enable __deprecated logic"
14 default y
15 help
16 Enable the __deprecated logic in the kernel build.
17 Disable this to suppress the "warning: 'foo' is deprecated
18 (declared at kernel/power/somefile.c:1234)" messages.
20 config ENABLE_MUST_CHECK
21 bool "Enable __must_check logic"
22 default y
23 help
24 Enable the __must_check logic in the kernel build. Disable this to
25 suppress the "warning: ignoring return value of 'foo', declared with
26 attribute warn_unused_result" messages.
28 config FRAME_WARN
29 int "Warn for stack frames larger than (needs gcc 4.4)"
30 range 0 8192
31 default 1024 if !64BIT
32 default 2048 if 64BIT
33 help
34 Tell gcc to warn at build time for stack frames larger than this.
35 Setting this too low will cause a lot of warnings.
36 Setting it to 0 disables the warning.
37 Requires gcc 4.4
39 config MAGIC_SYSRQ
40 bool "Magic SysRq key"
41 depends on !UML
42 help
43 If you say Y here, you will have some control over the system even
44 if the system crashes for example during kernel debugging (e.g., you
45 will be able to flush the buffer cache to disk, reboot the system
46 immediately or dump some status information). This is accomplished
47 by pressing various keys while holding SysRq (Alt+PrintScreen). It
48 also works on a serial console (on PC hardware at least), if you
49 send a BREAK and then within 5 seconds a command keypress. The
50 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
51 unless you really know what this hack does.
53 config STRIP_ASM_SYMS
54 bool "Strip assembler-generated symbols during link"
55 default n
56 help
57 Strip internal assembler-generated symbols during a link (symbols
58 that look like '.Lxxx') so they don't pollute the output of
59 get_wchan() and suchlike.
61 config UNUSED_SYMBOLS
62 bool "Enable unused/obsolete exported symbols"
63 default y if X86
64 help
65 Unused but exported symbols make the kernel needlessly bigger. For
66 that reason most of these unused exports will soon be removed. This
67 option is provided temporarily to provide a transition period in case
68 some external kernel module needs one of these symbols anyway. If you
69 encounter such a case in your module, consider if you are actually
70 using the right API. (rationale: since nobody in the kernel is using
71 this in a module, there is a pretty good chance it's actually the
72 wrong interface to use). If you really need the symbol, please send a
73 mail to the linux kernel mailing list mentioning the symbol and why
74 you really need it, and what the merge plan to the mainline kernel for
75 your module is.
77 config DEBUG_FS
78 bool "Debug Filesystem"
79 help
80 debugfs is a virtual file system that kernel developers use to put
81 debugging files into. Enable this option to be able to read and
82 write to these files.
84 For detailed documentation on the debugfs API, see
85 Documentation/DocBook/filesystems.
87 If unsure, say N.
89 config HEADERS_CHECK
90 bool "Run 'make headers_check' when building vmlinux"
91 depends on !UML
92 help
93 This option will extract the user-visible kernel headers whenever
94 building the kernel, and will run basic sanity checks on them to
95 ensure that exported files do not attempt to include files which
96 were not exported, etc.
98 If you're making modifications to header files which are
99 relevant for userspace, say 'Y', and check the headers
100 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
101 your build tree), to make sure they're suitable.
103 config DEBUG_SECTION_MISMATCH
104 bool "Enable full Section mismatch analysis"
105 depends on UNDEFINED || (BLACKFIN)
106 default y
107 # This option is on purpose disabled for now.
108 # It will be enabled when we are down to a reasonable number
109 # of section mismatch warnings (< 10 for an allyesconfig build)
110 help
111 The section mismatch analysis checks if there are illegal
112 references from one section to another section.
113 Linux will during link or during runtime drop some sections
114 and any use of code/data previously in these sections will
115 most likely result in an oops.
116 In the code functions and variables are annotated with
117 __init, __devinit etc. (see full list in include/linux/init.h)
118 which results in the code/data being placed in specific sections.
119 The section mismatch analysis is always done after a full
120 kernel build but enabling this option will in addition
121 do the following:
122 - Add the option -fno-inline-functions-called-once to gcc
123 When inlining a function annotated __init in a non-init
124 function we would lose the section information and thus
125 the analysis would not catch the illegal reference.
126 This option tells gcc to inline less but will also
127 result in a larger kernel.
128 - Run the section mismatch analysis for each module/built-in.o
129 When we run the section mismatch analysis on vmlinux.o we
130 lose valueble information about where the mismatch was
131 introduced.
132 Running the analysis for each module/built-in.o file
133 will tell where the mismatch happens much closer to the
134 source. The drawback is that we will report the same
135 mismatch at least twice.
136 - Enable verbose reporting from modpost to help solving
137 the section mismatches reported.
139 config DEBUG_KERNEL
140 bool "Kernel debugging"
141 help
142 Say Y here if you are developing drivers or trying to debug and
143 identify kernel problems.
145 config DEBUG_SHIRQ
146 bool "Debug shared IRQ handlers"
147 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
148 help
149 Enable this to generate a spurious interrupt as soon as a shared
150 interrupt handler is registered, and just before one is deregistered.
151 Drivers ought to be able to handle interrupts coming in at those
152 points; some don't and need to be caught.
154 config LOCKUP_DETECTOR
155 bool "Detect Hard and Soft Lockups"
156 depends on DEBUG_KERNEL && !S390
157 help
158 Say Y here to enable the kernel to act as a watchdog to detect
159 hard and soft lockups.
161 Softlockups are bugs that cause the kernel to loop in kernel
162 mode for more than 60 seconds, without giving other tasks a
163 chance to run. The current stack trace is displayed upon
164 detection and the system will stay locked up.
166 Hardlockups are bugs that cause the CPU to loop in kernel mode
167 for more than 60 seconds, without letting other interrupts have a
168 chance to run. The current stack trace is displayed upon detection
169 and the system will stay locked up.
171 The overhead should be minimal. A periodic hrtimer runs to
172 generate interrupts and kick the watchdog task every 10-12 seconds.
173 An NMI is generated every 60 seconds or so to check for hardlockups.
175 config HARDLOCKUP_DETECTOR
176 def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI
178 config BOOTPARAM_SOFTLOCKUP_PANIC
179 bool "Panic (Reboot) On Soft Lockups"
180 depends on LOCKUP_DETECTOR
181 help
182 Say Y here to enable the kernel to panic on "soft lockups",
183 which are bugs that cause the kernel to loop in kernel
184 mode for more than 60 seconds, without giving other tasks a
185 chance to run.
187 The panic can be used in combination with panic_timeout,
188 to cause the system to reboot automatically after a
189 lockup has been detected. This feature is useful for
190 high-availability systems that have uptime guarantees and
191 where a lockup must be resolved ASAP.
193 Say N if unsure.
195 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
196 int
197 depends on LOCKUP_DETECTOR
198 range 0 1
199 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
200 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
202 config DETECT_HUNG_TASK
203 bool "Detect Hung Tasks"
204 depends on DEBUG_KERNEL
205 default DETECT_SOFTLOCKUP
206 help
207 Say Y here to enable the kernel to detect "hung tasks",
208 which are bugs that cause the task to be stuck in
209 uninterruptible "D" state indefinitiley.
211 When a hung task is detected, the kernel will print the
212 current stack trace (which you should report), but the
213 task will stay in uninterruptible state. If lockdep is
214 enabled then all held locks will also be reported. This
215 feature has negligible overhead.
217 config BOOTPARAM_HUNG_TASK_PANIC
218 bool "Panic (Reboot) On Hung Tasks"
219 depends on DETECT_HUNG_TASK
220 help
221 Say Y here to enable the kernel to panic on "hung tasks",
222 which are bugs that cause the kernel to leave a task stuck
223 in uninterruptible "D" state.
225 The panic can be used in combination with panic_timeout,
226 to cause the system to reboot automatically after a
227 hung task has been detected. This feature is useful for
228 high-availability systems that have uptime guarantees and
229 where a hung tasks must be resolved ASAP.
231 Say N if unsure.
233 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
234 int
235 depends on DETECT_HUNG_TASK
236 range 0 1
237 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
238 default 1 if BOOTPARAM_HUNG_TASK_PANIC
240 config SCHED_DEBUG
241 bool "Collect scheduler debugging info"
242 depends on DEBUG_KERNEL && PROC_FS
243 default y
244 help
245 If you say Y here, the /proc/sched_debug file will be provided
246 that can help debug the scheduler. The runtime overhead of this
247 option is minimal.
249 config SCHEDSTATS
250 bool "Collect scheduler statistics"
251 depends on DEBUG_KERNEL && PROC_FS
252 help
253 If you say Y here, additional code will be inserted into the
254 scheduler and related routines to collect statistics about
255 scheduler behavior and provide them in /proc/schedstat. These
256 stats may be useful for both tuning and debugging the scheduler
257 If you aren't debugging the scheduler or trying to tune a specific
258 application, you can say N to avoid the very slight overhead
259 this adds.
261 config TIMER_STATS
262 bool "Collect kernel timers statistics"
263 depends on DEBUG_KERNEL && PROC_FS
264 help
265 If you say Y here, additional code will be inserted into the
266 timer routines to collect statistics about kernel timers being
267 reprogrammed. The statistics can be read from /proc/timer_stats.
268 The statistics collection is started by writing 1 to /proc/timer_stats,
269 writing 0 stops it. This feature is useful to collect information
270 about timer usage patterns in kernel and userspace. This feature
271 is lightweight if enabled in the kernel config but not activated
272 (it defaults to deactivated on bootup and will only be activated
273 if some application like powertop activates it explicitly).
275 config DEBUG_OBJECTS
276 bool "Debug object operations"
277 depends on DEBUG_KERNEL
278 help
279 If you say Y here, additional code will be inserted into the
280 kernel to track the life time of various objects and validate
281 the operations on those objects.
283 config DEBUG_OBJECTS_SELFTEST
284 bool "Debug objects selftest"
285 depends on DEBUG_OBJECTS
286 help
287 This enables the selftest of the object debug code.
289 config DEBUG_OBJECTS_FREE
290 bool "Debug objects in freed memory"
291 depends on DEBUG_OBJECTS
292 help
293 This enables checks whether a k/v free operation frees an area
294 which contains an object which has not been deactivated
295 properly. This can make kmalloc/kfree-intensive workloads
296 much slower.
298 config DEBUG_OBJECTS_TIMERS
299 bool "Debug timer objects"
300 depends on DEBUG_OBJECTS
301 help
302 If you say Y here, additional code will be inserted into the
303 timer routines to track the life time of timer objects and
304 validate the timer operations.
306 config DEBUG_OBJECTS_WORK
307 bool "Debug work objects"
308 depends on DEBUG_OBJECTS
309 help
310 If you say Y here, additional code will be inserted into the
311 work queue routines to track the life time of work objects and
312 validate the work operations.
314 config DEBUG_OBJECTS_RCU_HEAD
315 bool "Debug RCU callbacks objects"
316 depends on DEBUG_OBJECTS && PREEMPT
317 help
318 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
320 config DEBUG_OBJECTS_ENABLE_DEFAULT
321 int "debug_objects bootup default value (0-1)"
322 range 0 1
323 default "1"
324 depends on DEBUG_OBJECTS
325 help
326 Debug objects boot parameter default value
328 config DEBUG_SLAB
329 bool "Debug slab memory allocations"
330 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
331 help
332 Say Y here to have the kernel do limited verification on memory
333 allocation as well as poisoning memory on free to catch use of freed
334 memory. This can make kmalloc/kfree-intensive workloads much slower.
336 config DEBUG_SLAB_LEAK
337 bool "Memory leak debugging"
338 depends on DEBUG_SLAB
340 config SLUB_DEBUG_ON
341 bool "SLUB debugging on by default"
342 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
343 default n
344 help
345 Boot with debugging on by default. SLUB boots by default with
346 the runtime debug capabilities switched off. Enabling this is
347 equivalent to specifying the "slub_debug" parameter on boot.
348 There is no support for more fine grained debug control like
349 possible with slub_debug=xxx. SLUB debugging may be switched
350 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
351 "slub_debug=-".
353 config SLUB_STATS
354 default n
355 bool "Enable SLUB performance statistics"
356 depends on SLUB && SYSFS
357 help
358 SLUB statistics are useful to debug SLUBs allocation behavior in
359 order find ways to optimize the allocator. This should never be
360 enabled for production use since keeping statistics slows down
361 the allocator by a few percentage points. The slabinfo command
362 supports the determination of the most active slabs to figure
363 out which slabs are relevant to a particular load.
364 Try running: slabinfo -DA
366 config DEBUG_KMEMLEAK
367 bool "Kernel memory leak detector"
368 depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
369 (X86 || ARM || PPC || S390 || SPARC64 || SUPERH || MICROBLAZE)
371 select DEBUG_FS if SYSFS
372 select STACKTRACE if STACKTRACE_SUPPORT
373 select KALLSYMS
374 select CRC32
375 help
376 Say Y here if you want to enable the memory leak
377 detector. The memory allocation/freeing is traced in a way
378 similar to the Boehm's conservative garbage collector, the
379 difference being that the orphan objects are not freed but
380 only shown in /sys/kernel/debug/kmemleak. Enabling this
381 feature will introduce an overhead to memory
382 allocations. See Documentation/kmemleak.txt for more
383 details.
385 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
386 of finding leaks due to the slab objects poisoning.
388 In order to access the kmemleak file, debugfs needs to be
389 mounted (usually at /sys/kernel/debug).
391 config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
392 int "Maximum kmemleak early log entries"
393 depends on DEBUG_KMEMLEAK
394 range 200 40000
395 default 400
396 help
397 Kmemleak must track all the memory allocations to avoid
398 reporting false positives. Since memory may be allocated or
399 freed before kmemleak is initialised, an early log buffer is
400 used to store these actions. If kmemleak reports "early log
401 buffer exceeded", please increase this value.
403 config DEBUG_KMEMLEAK_TEST
404 tristate "Simple test for the kernel memory leak detector"
405 depends on DEBUG_KMEMLEAK
406 help
407 Say Y or M here to build a test for the kernel memory leak
408 detector. This option enables a module that explicitly leaks
409 memory.
411 If unsure, say N.
413 config DEBUG_KMEMLEAK_DEFAULT_OFF
414 bool "Default kmemleak to off"
415 depends on DEBUG_KMEMLEAK
416 help
417 Say Y here to disable kmemleak by default. It can then be enabled
418 on the command line via kmemleak=on.
420 config DEBUG_PREEMPT
421 bool "Debug preemptible kernel"
422 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
423 default y
424 help
425 If you say Y here then the kernel will use a debug variant of the
426 commonly used smp_processor_id() function and will print warnings
427 if kernel code uses it in a preemption-unsafe way. Also, the kernel
428 will detect preemption count underflows.
430 config DEBUG_RT_MUTEXES
431 bool "RT Mutex debugging, deadlock detection"
432 depends on DEBUG_KERNEL && RT_MUTEXES
433 help
434 This allows rt mutex semantics violations and rt mutex related
435 deadlocks (lockups) to be detected and reported automatically.
437 config DEBUG_PI_LIST
438 bool
439 default y
440 depends on DEBUG_RT_MUTEXES
442 config RT_MUTEX_TESTER
443 bool "Built-in scriptable tester for rt-mutexes"
444 depends on DEBUG_KERNEL && RT_MUTEXES
445 help
446 This option enables a rt-mutex tester.
448 config DEBUG_SPINLOCK
449 bool "Spinlock and rw-lock debugging: basic checks"
450 depends on DEBUG_KERNEL
451 help
452 Say Y here and build SMP to catch missing spinlock initialization
453 and certain other kinds of spinlock errors commonly made. This is
454 best used in conjunction with the NMI watchdog so that spinlock
455 deadlocks are also debuggable.
457 config DEBUG_MUTEXES
458 bool "Mutex debugging: basic checks"
459 depends on DEBUG_KERNEL
460 help
461 This feature allows mutex semantics violations to be detected and
462 reported.
464 config BKL
465 bool "Big Kernel Lock" if (SMP || PREEMPT)
466 default y
467 help
468 This is the traditional lock that is used in old code instead
469 of proper locking. All drivers that use the BKL should depend
470 on this symbol.
471 Say Y here unless you are working on removing the BKL.
473 config DEBUG_LOCK_ALLOC
474 bool "Lock debugging: detect incorrect freeing of live locks"
475 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
476 select DEBUG_SPINLOCK
477 select DEBUG_MUTEXES
478 select LOCKDEP
479 help
480 This feature will check whether any held lock (spinlock, rwlock,
481 mutex or rwsem) is incorrectly freed by the kernel, via any of the
482 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
483 vfree(), etc.), whether a live lock is incorrectly reinitialized via
484 spin_lock_init()/mutex_init()/etc., or whether there is any lock
485 held during task exit.
487 config PROVE_LOCKING
488 bool "Lock debugging: prove locking correctness"
489 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
490 select LOCKDEP
491 select DEBUG_SPINLOCK
492 select DEBUG_MUTEXES
493 select DEBUG_LOCK_ALLOC
494 select TRACE_IRQFLAGS
495 default n
496 help
497 This feature enables the kernel to prove that all locking
498 that occurs in the kernel runtime is mathematically
499 correct: that under no circumstance could an arbitrary (and
500 not yet triggered) combination of observed locking
501 sequences (on an arbitrary number of CPUs, running an
502 arbitrary number of tasks and interrupt contexts) cause a
503 deadlock.
505 In short, this feature enables the kernel to report locking
506 related deadlocks before they actually occur.
508 The proof does not depend on how hard and complex a
509 deadlock scenario would be to trigger: how many
510 participant CPUs, tasks and irq-contexts would be needed
511 for it to trigger. The proof also does not depend on
512 timing: if a race and a resulting deadlock is possible
513 theoretically (no matter how unlikely the race scenario
514 is), it will be proven so and will immediately be
515 reported by the kernel (once the event is observed that
516 makes the deadlock theoretically possible).
518 If a deadlock is impossible (i.e. the locking rules, as
519 observed by the kernel, are mathematically correct), the
520 kernel reports nothing.
522 NOTE: this feature can also be enabled for rwlocks, mutexes
523 and rwsems - in which case all dependencies between these
524 different locking variants are observed and mapped too, and
525 the proof of observed correctness is also maintained for an
526 arbitrary combination of these separate locking variants.
528 For more details, see Documentation/lockdep-design.txt.
530 config PROVE_RCU
531 bool "RCU debugging: prove RCU correctness"
532 depends on PROVE_LOCKING
533 default n
534 help
535 This feature enables lockdep extensions that check for correct
536 use of RCU APIs. This is currently under development. Say Y
537 if you want to debug RCU usage or help work on the PROVE_RCU
538 feature.
540 Say N if you are unsure.
542 config PROVE_RCU_REPEATEDLY
543 bool "RCU debugging: don't disable PROVE_RCU on first splat"
544 depends on PROVE_RCU
545 default n
546 help
547 By itself, PROVE_RCU will disable checking upon issuing the
548 first warning (or "splat"). This feature prevents such
549 disabling, allowing multiple RCU-lockdep warnings to be printed
550 on a single reboot.
552 Say Y to allow multiple RCU-lockdep warnings per boot.
554 Say N if you are unsure.
556 config SPARSE_RCU_POINTER
557 bool "RCU debugging: sparse-based checks for pointer usage"
558 default n
559 help
560 This feature enables the __rcu sparse annotation for
561 RCU-protected pointers. This annotation will cause sparse
562 to flag any non-RCU used of annotated pointers. This can be
563 helpful when debugging RCU usage. Please note that this feature
564 is not intended to enforce code cleanliness; it is instead merely
565 a debugging aid.
567 Say Y to make sparse flag questionable use of RCU-protected pointers
569 Say N if you are unsure.
571 config LOCKDEP
572 bool
573 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
574 select STACKTRACE
575 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
576 select KALLSYMS
577 select KALLSYMS_ALL
579 config LOCK_STAT
580 bool "Lock usage statistics"
581 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
582 select LOCKDEP
583 select DEBUG_SPINLOCK
584 select DEBUG_MUTEXES
585 select DEBUG_LOCK_ALLOC
586 default n
587 help
588 This feature enables tracking lock contention points
590 For more details, see Documentation/lockstat.txt
592 This also enables lock events required by "perf lock",
593 subcommand of perf.
594 If you want to use "perf lock", you also need to turn on
595 CONFIG_EVENT_TRACING.
597 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
598 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
600 config DEBUG_LOCKDEP
601 bool "Lock dependency engine debugging"
602 depends on DEBUG_KERNEL && LOCKDEP
603 help
604 If you say Y here, the lock dependency engine will do
605 additional runtime checks to debug itself, at the price
606 of more runtime overhead.
608 config TRACE_IRQFLAGS
609 bool
610 help
611 Enables hooks to interrupt enabling and disabling for
612 either tracing or lock debugging.
614 config DEBUG_SPINLOCK_SLEEP
615 bool "Spinlock debugging: sleep-inside-spinlock checking"
616 depends on DEBUG_KERNEL
617 help
618 If you say Y here, various routines which may sleep will become very
619 noisy if they are called with a spinlock held.
621 config DEBUG_LOCKING_API_SELFTESTS
622 bool "Locking API boot-time self-tests"
623 depends on DEBUG_KERNEL
624 help
625 Say Y here if you want the kernel to run a short self-test during
626 bootup. The self-test checks whether common types of locking bugs
627 are detected by debugging mechanisms or not. (if you disable
628 lock debugging then those bugs wont be detected of course.)
629 The following locking APIs are covered: spinlocks, rwlocks,
630 mutexes and rwsems.
632 config STACKTRACE
633 bool
634 depends on STACKTRACE_SUPPORT
636 config DEBUG_KOBJECT
637 bool "kobject debugging"
638 depends on DEBUG_KERNEL
639 help
640 If you say Y here, some extra kobject debugging messages will be sent
641 to the syslog.
643 config DEBUG_HIGHMEM
644 bool "Highmem debugging"
645 depends on DEBUG_KERNEL && HIGHMEM
646 help
647 This options enables addition error checking for high memory systems.
648 Disable for production systems.
650 config DEBUG_BUGVERBOSE
651 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
652 depends on BUG
653 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
654 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
655 default y
656 help
657 Say Y here to make BUG() panics output the file name and line number
658 of the BUG call as well as the EIP and oops trace. This aids
659 debugging but costs about 70-100K of memory.
661 config DEBUG_INFO
662 bool "Compile the kernel with debug info"
663 depends on DEBUG_KERNEL
664 help
665 If you say Y here the resulting kernel image will include
666 debugging info resulting in a larger kernel image.
667 This adds debug symbols to the kernel and modules (gcc -g), and
668 is needed if you intend to use kernel crashdump or binary object
669 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
670 Say Y here only if you plan to debug the kernel.
672 If unsure, say N.
674 config DEBUG_INFO_REDUCED
675 bool "Reduce debugging information"
676 depends on DEBUG_INFO
677 help
678 If you say Y here gcc is instructed to generate less debugging
679 information for structure types. This means that tools that
680 need full debugging information (like kgdb or systemtap) won't
681 be happy. But if you merely need debugging information to
682 resolve line numbers there is no loss. Advantage is that
683 build directory object sizes shrink dramatically over a full
684 DEBUG_INFO build and compile times are reduced too.
685 Only works with newer gcc versions.
687 config DEBUG_VM
688 bool "Debug VM"
689 depends on DEBUG_KERNEL
690 help
691 Enable this to turn on extended checks in the virtual-memory system
692 that may impact performance.
694 If unsure, say N.
696 config DEBUG_VIRTUAL
697 bool "Debug VM translations"
698 depends on DEBUG_KERNEL && X86
699 help
700 Enable some costly sanity checks in virtual to page code. This can
701 catch mistakes with virt_to_page() and friends.
703 If unsure, say N.
705 config DEBUG_NOMMU_REGIONS
706 bool "Debug the global anon/private NOMMU mapping region tree"
707 depends on DEBUG_KERNEL && !MMU
708 help
709 This option causes the global tree of anonymous and private mapping
710 regions to be regularly checked for invalid topology.
712 config DEBUG_WRITECOUNT
713 bool "Debug filesystem writers count"
714 depends on DEBUG_KERNEL
715 help
716 Enable this to catch wrong use of the writers count in struct
717 vfsmount. This will increase the size of each file struct by
718 32 bits.
720 If unsure, say N.
722 config DEBUG_MEMORY_INIT
723 bool "Debug memory initialisation" if EMBEDDED
724 default !EMBEDDED
725 help
726 Enable this for additional checks during memory initialisation.
727 The sanity checks verify aspects of the VM such as the memory model
728 and other information provided by the architecture. Verbose
729 information will be printed at KERN_DEBUG loglevel depending
730 on the mminit_loglevel= command-line option.
732 If unsure, say Y
734 config DEBUG_LIST
735 bool "Debug linked list manipulation"
736 depends on DEBUG_KERNEL
737 help
738 Enable this to turn on extended checks in the linked-list
739 walking routines.
741 If unsure, say N.
743 config DEBUG_SG
744 bool "Debug SG table operations"
745 depends on DEBUG_KERNEL
746 help
747 Enable this to turn on checks on scatter-gather tables. This can
748 help find problems with drivers that do not properly initialize
749 their sg tables.
751 If unsure, say N.
753 config DEBUG_NOTIFIERS
754 bool "Debug notifier call chains"
755 depends on DEBUG_KERNEL
756 help
757 Enable this to turn on sanity checking for notifier call chains.
758 This is most useful for kernel developers to make sure that
759 modules properly unregister themselves from notifier chains.
760 This is a relatively cheap check but if you care about maximum
761 performance, say N.
763 config DEBUG_CREDENTIALS
764 bool "Debug credential management"
765 depends on DEBUG_KERNEL
766 help
767 Enable this to turn on some debug checking for credential
768 management. The additional code keeps track of the number of
769 pointers from task_structs to any given cred struct, and checks to
770 see that this number never exceeds the usage count of the cred
771 struct.
773 Furthermore, if SELinux is enabled, this also checks that the
774 security pointer in the cred struct is never seen to be invalid.
776 If unsure, say N.
778 #
779 # Select this config option from the architecture Kconfig, if it
780 # it is preferred to always offer frame pointers as a config
781 # option on the architecture (regardless of KERNEL_DEBUG):
782 #
783 config ARCH_WANT_FRAME_POINTERS
784 bool
785 help
787 config FRAME_POINTER
788 bool "Compile the kernel with frame pointers"
789 depends on DEBUG_KERNEL && \
790 (CRIS || M68K || M68KNOMMU || FRV || UML || \
791 AVR32 || SUPERH || BLACKFIN || MN10300) || \
792 ARCH_WANT_FRAME_POINTERS
793 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
794 help
795 If you say Y here the resulting kernel image will be slightly
796 larger and slower, but it gives very useful debugging information
797 in case of kernel bugs. (precise oopses/stacktraces/warnings)
799 config BOOT_PRINTK_DELAY
800 bool "Delay each boot printk message by N milliseconds"
801 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
802 help
803 This build option allows you to read kernel boot messages
804 by inserting a short delay after each one. The delay is
805 specified in milliseconds on the kernel command line,
806 using "boot_delay=N".
808 It is likely that you would also need to use "lpj=M" to preset
809 the "loops per jiffie" value.
810 See a previous boot log for the "lpj" value to use for your
811 system, and then set "lpj=M" before setting "boot_delay=N".
812 NOTE: Using this option may adversely affect SMP systems.
813 I.e., processors other than the first one may not boot up.
814 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
815 what it believes to be lockup conditions.
817 config RCU_TORTURE_TEST
818 tristate "torture tests for RCU"
819 depends on DEBUG_KERNEL
820 default n
821 help
822 This option provides a kernel module that runs torture tests
823 on the RCU infrastructure. The kernel module may be built
824 after the fact on the running kernel to be tested, if desired.
826 Say Y here if you want RCU torture tests to be built into
827 the kernel.
828 Say M if you want the RCU torture tests to build as a module.
829 Say N if you are unsure.
831 config RCU_TORTURE_TEST_RUNNABLE
832 bool "torture tests for RCU runnable by default"
833 depends on RCU_TORTURE_TEST = y
834 default n
835 help
836 This option provides a way to build the RCU torture tests
837 directly into the kernel without them starting up at boot
838 time. You can use /proc/sys/kernel/rcutorture_runnable
839 to manually override this setting. This /proc file is
840 available only when the RCU torture tests have been built
841 into the kernel.
843 Say Y here if you want the RCU torture tests to start during
844 boot (you probably don't).
845 Say N here if you want the RCU torture tests to start only
846 after being manually enabled via /proc.
848 config RCU_CPU_STALL_DETECTOR
849 bool "Check for stalled CPUs delaying RCU grace periods"
850 depends on TREE_RCU || TREE_PREEMPT_RCU
851 default y
852 help
853 This option causes RCU to printk information on which
854 CPUs are delaying the current grace period, but only when
855 the grace period extends for excessive time periods.
857 Say N if you want to disable such checks.
859 Say Y if you are unsure.
861 config RCU_CPU_STALL_TIMEOUT
862 int "RCU CPU stall timeout in seconds"
863 depends on RCU_CPU_STALL_DETECTOR
864 range 3 300
865 default 60
866 help
867 If a given RCU grace period extends more than the specified
868 number of seconds, a CPU stall warning is printed. If the
869 RCU grace period persists, additional CPU stall warnings are
870 printed at more widely spaced intervals.
872 config RCU_CPU_STALL_DETECTOR_RUNNABLE
873 bool "RCU CPU stall checking starts automatically at boot"
874 depends on RCU_CPU_STALL_DETECTOR
875 default y
876 help
877 If set, start checking for RCU CPU stalls immediately on
878 boot. Otherwise, RCU CPU stall checking must be manually
879 enabled.
881 Say Y if you are unsure.
883 Say N if you wish to suppress RCU CPU stall checking during boot.
885 config RCU_CPU_STALL_VERBOSE
886 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
887 depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU
888 default y
889 help
890 This option causes RCU to printk detailed per-task information
891 for any tasks that are stalling the current RCU grace period.
893 Say N if you are unsure.
895 Say Y if you want to enable such checks.
897 config KPROBES_SANITY_TEST
898 bool "Kprobes sanity tests"
899 depends on DEBUG_KERNEL
900 depends on KPROBES
901 default n
902 help
903 This option provides for testing basic kprobes functionality on
904 boot. A sample kprobe, jprobe and kretprobe are inserted and
905 verified for functionality.
907 Say N if you are unsure.
909 config BACKTRACE_SELF_TEST
910 tristate "Self test for the backtrace code"
911 depends on DEBUG_KERNEL
912 default n
913 help
914 This option provides a kernel module that can be used to test
915 the kernel stack backtrace code. This option is not useful
916 for distributions or general kernels, but only for kernel
917 developers working on architecture code.
919 Note that if you want to also test saved backtraces, you will
920 have to enable STACKTRACE as well.
922 Say N if you are unsure.
924 config DEBUG_BLOCK_EXT_DEVT
925 bool "Force extended block device numbers and spread them"
926 depends on DEBUG_KERNEL
927 depends on BLOCK
928 default n
929 help
930 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
931 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
932 YOU ARE DOING. Distros, please enable this and fix whatever
933 is broken.
935 Conventionally, block device numbers are allocated from
936 predetermined contiguous area. However, extended block area
937 may introduce non-contiguous block device numbers. This
938 option forces most block device numbers to be allocated from
939 the extended space and spreads them to discover kernel or
940 userland code paths which assume predetermined contiguous
941 device number allocation.
943 Note that turning on this debug option shuffles all the
944 device numbers for all IDE and SCSI devices including libata
945 ones, so root partition specified using device number
946 directly (via rdev or root=MAJ:MIN) won't work anymore.
947 Textual device names (root=/dev/sdXn) will continue to work.
949 Say N if you are unsure.
951 config DEBUG_FORCE_WEAK_PER_CPU
952 bool "Force weak per-cpu definitions"
953 depends on DEBUG_KERNEL
954 help
955 s390 and alpha require percpu variables in modules to be
956 defined weak to work around addressing range issue which
957 puts the following two restrictions on percpu variable
958 definitions.
960 1. percpu symbols must be unique whether static or not
961 2. percpu variables can't be defined inside a function
963 To ensure that generic code follows the above rules, this
964 option forces all percpu variables to be defined as weak.
966 config LKDTM
967 tristate "Linux Kernel Dump Test Tool Module"
968 depends on DEBUG_FS
969 depends on BLOCK
970 default n
971 help
972 This module enables testing of the different dumping mechanisms by
973 inducing system failures at predefined crash points.
974 If you don't need it: say N
975 Choose M here to compile this code as a module. The module will be
976 called lkdtm.
978 Documentation on how to use the module can be found in
979 Documentation/fault-injection/provoke-crashes.txt
981 config CPU_NOTIFIER_ERROR_INJECT
982 tristate "CPU notifier error injection module"
983 depends on HOTPLUG_CPU && DEBUG_KERNEL
984 help
985 This option provides a kernel module that can be used to test
986 the error handling of the cpu notifiers
988 To compile this code as a module, choose M here: the module will
989 be called cpu-notifier-error-inject.
991 If unsure, say N.
993 config FAULT_INJECTION
994 bool "Fault-injection framework"
995 depends on DEBUG_KERNEL
996 help
997 Provide fault-injection framework.
998 For more details, see Documentation/fault-injection/.
1000 config FAILSLAB
1001 bool "Fault-injection capability for kmalloc"
1002 depends on FAULT_INJECTION
1003 depends on SLAB || SLUB
1004 help
1005 Provide fault-injection capability for kmalloc.
1007 config FAIL_PAGE_ALLOC
1008 bool "Fault-injection capabilitiy for alloc_pages()"
1009 depends on FAULT_INJECTION
1010 help
1011 Provide fault-injection capability for alloc_pages().
1013 config FAIL_MAKE_REQUEST
1014 bool "Fault-injection capability for disk IO"
1015 depends on FAULT_INJECTION && BLOCK
1016 help
1017 Provide fault-injection capability for disk IO.
1019 config FAIL_IO_TIMEOUT
1020 bool "Fault-injection capability for faking disk interrupts"
1021 depends on FAULT_INJECTION && BLOCK
1022 help
1023 Provide fault-injection capability on end IO handling. This
1024 will make the block layer "forget" an interrupt as configured,
1025 thus exercising the error handling.
1027 Only works with drivers that use the generic timeout handling,
1028 for others it wont do anything.
1030 config FAULT_INJECTION_DEBUG_FS
1031 bool "Debugfs entries for fault-injection capabilities"
1032 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1033 help
1034 Enable configuration of fault-injection capabilities via debugfs.
1036 config FAULT_INJECTION_STACKTRACE_FILTER
1037 bool "stacktrace filter for fault-injection capabilities"
1038 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1039 depends on !X86_64
1040 select STACKTRACE
1041 select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE
1042 help
1043 Provide stacktrace filter for fault-injection capabilities
1045 config LATENCYTOP
1046 bool "Latency measuring infrastructure"
1047 depends on HAVE_LATENCYTOP_SUPPORT
1048 depends on DEBUG_KERNEL
1049 depends on STACKTRACE_SUPPORT
1050 depends on PROC_FS
1051 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE
1052 select KALLSYMS
1053 select KALLSYMS_ALL
1054 select STACKTRACE
1055 select SCHEDSTATS
1056 select SCHED_DEBUG
1057 help
1058 Enable this option if you want to use the LatencyTOP tool
1059 to find out which userspace is blocking on what kernel operations.
1061 config SYSCTL_SYSCALL_CHECK
1062 bool "Sysctl checks"
1063 depends on SYSCTL
1064 ---help---
1065 sys_sysctl uses binary paths that have been found challenging
1066 to properly maintain and use. This enables checks that help
1067 you to keep things correct.
1069 source mm/Kconfig.debug
1070 source kernel/trace/Kconfig
1072 config PROVIDE_OHCI1394_DMA_INIT
1073 bool "Remote debugging over FireWire early on boot"
1074 depends on PCI && X86
1075 help
1076 If you want to debug problems which hang or crash the kernel early
1077 on boot and the crashing machine has a FireWire port, you can use
1078 this feature to remotely access the memory of the crashed machine
1079 over FireWire. This employs remote DMA as part of the OHCI1394
1080 specification which is now the standard for FireWire controllers.
1082 With remote DMA, you can monitor the printk buffer remotely using
1083 firescope and access all memory below 4GB using fireproxy from gdb.
1084 Even controlling a kernel debugger is possible using remote DMA.
1086 Usage:
1088 If ohci1394_dma=early is used as boot parameter, it will initialize
1089 all OHCI1394 controllers which are found in the PCI config space.
1091 As all changes to the FireWire bus such as enabling and disabling
1092 devices cause a bus reset and thereby disable remote DMA for all
1093 devices, be sure to have the cable plugged and FireWire enabled on
1094 the debugging host before booting the debug target for debugging.
1096 This code (~1k) is freed after boot. By then, the firewire stack
1097 in charge of the OHCI-1394 controllers should be used instead.
1099 See Documentation/debugging-via-ohci1394.txt for more information.
1101 config FIREWIRE_OHCI_REMOTE_DMA
1102 bool "Remote debugging over FireWire with firewire-ohci"
1103 depends on FIREWIRE_OHCI
1104 help
1105 This option lets you use the FireWire bus for remote debugging
1106 with help of the firewire-ohci driver. It enables unfiltered
1107 remote DMA in firewire-ohci.
1108 See Documentation/debugging-via-ohci1394.txt for more information.
1110 If unsure, say N.
1112 config BUILD_DOCSRC
1113 bool "Build targets in Documentation/ tree"
1114 depends on HEADERS_CHECK
1115 help
1116 This option attempts to build objects from the source files in the
1117 kernel Documentation/ tree.
1119 Say N if you are unsure.
1121 config DYNAMIC_DEBUG
1122 bool "Enable dynamic printk() support"
1123 default n
1124 depends on PRINTK
1125 depends on DEBUG_FS
1126 help
1128 Compiles debug level messages into the kernel, which would not
1129 otherwise be available at runtime. These messages can then be
1130 enabled/disabled based on various levels of scope - per source file,
1131 function, module, format string, and line number. This mechanism
1132 implicitly enables all pr_debug() and dev_dbg() calls. The impact of
1133 this compile option is a larger kernel text size of about 2%.
1135 Usage:
1137 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
1138 which is contained in the 'debugfs' filesystem. Thus, the debugfs
1139 filesystem must first be mounted before making use of this feature.
1140 We refer the control file as: <debugfs>/dynamic_debug/control. This
1141 file contains a list of the debug statements that can be enabled. The
1142 format for each line of the file is:
1144 filename:lineno [module]function flags format
1146 filename : source file of the debug statement
1147 lineno : line number of the debug statement
1148 module : module that contains the debug statement
1149 function : function that contains the debug statement
1150 flags : 'p' means the line is turned 'on' for printing
1151 format : the format used for the debug statement
1153 From a live system:
1155 nullarbor:~ # cat <debugfs>/dynamic_debug/control
1156 # filename:lineno [module]function flags format
1157 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
1158 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
1159 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
1161 Example usage:
1163 // enable the message at line 1603 of file svcsock.c
1164 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
1165 <debugfs>/dynamic_debug/control
1167 // enable all the messages in file svcsock.c
1168 nullarbor:~ # echo -n 'file svcsock.c +p' >
1169 <debugfs>/dynamic_debug/control
1171 // enable all the messages in the NFS server module
1172 nullarbor:~ # echo -n 'module nfsd +p' >
1173 <debugfs>/dynamic_debug/control
1175 // enable all 12 messages in the function svc_process()
1176 nullarbor:~ # echo -n 'func svc_process +p' >
1177 <debugfs>/dynamic_debug/control
1179 // disable all 12 messages in the function svc_process()
1180 nullarbor:~ # echo -n 'func svc_process -p' >
1181 <debugfs>/dynamic_debug/control
1183 See Documentation/dynamic-debug-howto.txt for additional information.
1185 config DMA_API_DEBUG
1186 bool "Enable debugging of DMA-API usage"
1187 depends on HAVE_DMA_API_DEBUG
1188 help
1189 Enable this option to debug the use of the DMA API by device drivers.
1190 With this option you will be able to detect common bugs in device
1191 drivers like double-freeing of DMA mappings or freeing mappings that
1192 were never allocated.
1193 This option causes a performance degredation. Use only if you want
1194 to debug device drivers. If unsure, say N.
1196 config ATOMIC64_SELFTEST
1197 bool "Perform an atomic64_t self-test at boot"
1198 help
1199 Enable this option to test the atomic64_t functions at boot.
1201 If unsure, say N.
1203 source "samples/Kconfig"
1205 source "lib/Kconfig.kgdb"
1207 source "lib/Kconfig.kmemcheck"