3 bool "Show timing information on printks"
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.
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.
14 The behavior is also controlled by the kernel command line
15 parameter printk.time=1. See Documentation/kernel-parameters.txt
17 config DEFAULT_MESSAGE_LOGLEVEL
18 int "Default message log level (1-7)"
22 Default log level for printk statements with no specified priority.
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
28 config ENABLE_WARN_DEPRECATED
29 bool "Enable __deprecated logic"
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.
36 config ENABLE_MUST_CHECK
37 bool "Enable __must_check logic"
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.
45 int "Warn for stack frames larger than (needs gcc 4.4)"
47 default 1024 if !64BIT
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.
56 bool "Magic SysRq key"
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.
70 bool "Strip assembler-generated symbols during link"
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.
78 bool "Generate readable assembler code"
79 depends on DEBUG_KERNEL
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
87 bool "Enable unused/obsolete exported symbols"
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
103 bool "Debug Filesystem"
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.
109 For detailed documentation on the debugfs API, see
110 Documentation/DocBook/filesystems.
115 bool "Run 'make headers_check' when building vmlinux"
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.
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.
128 config DEBUG_SECTION_MISMATCH
129 bool "Enable full Section mismatch analysis"
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
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
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.
160 bool "Kernel debugging"
162 Say Y here if you are developing drivers or trying to debug and
163 identify kernel problems.
166 bool "Compile with -O1 for debugging"
167 depends on DEBUG_KERNEL
170 Enable this if you are using a source level debugger and
171 experience poor correlation between the program counter
172 and the source display. This will reduce kernel peformance
173 and is only used when debugging.
176 bool "Debug shared IRQ handlers"
177 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
179 Enable this to generate a spurious interrupt as soon as a shared
180 interrupt handler is registered, and just before one is deregistered.
181 Drivers ought to be able to handle interrupts coming in at those
182 points; some don't and need to be caught.
184 config LOCKUP_DETECTOR
185 bool "Detect Hard and Soft Lockups"
186 depends on DEBUG_KERNEL && !S390
188 Say Y here to enable the kernel to act as a watchdog to detect
189 hard and soft lockups.
191 Softlockups are bugs that cause the kernel to loop in kernel
192 mode for more than 20 seconds, without giving other tasks a
193 chance to run. The current stack trace is displayed upon
194 detection and the system will stay locked up.
196 Hardlockups are bugs that cause the CPU to loop in kernel mode
197 for more than 10 seconds, without letting other interrupts have a
198 chance to run. The current stack trace is displayed upon detection
199 and the system will stay locked up.
201 The overhead should be minimal. A periodic hrtimer runs to
202 generate interrupts and kick the watchdog task every 4 seconds.
203 An NMI is generated every 10 seconds or so to check for hardlockups.
204 If NMIs are not available on the platform, every 12 seconds the
205 hrtimer interrupt on one cpu will be used to check for hardlockups
208 The frequency of hrtimer and NMI events and the soft and hard lockup
209 thresholds can be controlled through the sysctl watchdog_thresh.
211 config HARDLOCKUP_DETECTOR_NMI
213 depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG
214 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
216 config HARDLOCKUP_DETECTOR_OTHER_CPU
218 depends on LOCKUP_DETECTOR && SMP
219 depends on !HARDLOCKUP_DETECTOR_NMI && !HAVE_NMI_WATCHDOG
221 config HARDLOCKUP_DETECTOR
223 depends on HARDLOCKUP_DETECTOR_NMI || HARDLOCKUP_DETECTOR_OTHER_CPU
225 config BOOTPARAM_HARDLOCKUP_PANIC
226 bool "Panic (Reboot) On Hard Lockups"
227 depends on HARDLOCKUP_DETECTOR
229 Say Y here to enable the kernel to panic on "hard lockups",
230 which are bugs that cause the kernel to loop in kernel
231 mode with interrupts disabled for more than 10 seconds (configurable
232 using the watchdog_thresh sysctl).
236 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
238 depends on HARDLOCKUP_DETECTOR
240 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
241 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
243 config BOOTPARAM_SOFTLOCKUP_PANIC
244 bool "Panic (Reboot) On Soft Lockups"
245 depends on LOCKUP_DETECTOR
247 Say Y here to enable the kernel to panic on "soft lockups",
248 which are bugs that cause the kernel to loop in kernel
249 mode for more than 20 seconds (configurable using the watchdog_thresh
250 sysctl), without giving other tasks a chance to run.
252 The panic can be used in combination with panic_timeout,
253 to cause the system to reboot automatically after a
254 lockup has been detected. This feature is useful for
255 high-availability systems that have uptime guarantees and
256 where a lockup must be resolved ASAP.
260 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
262 depends on LOCKUP_DETECTOR
264 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
265 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
270 Say Y here to enable the kernel to panic when it oopses. This
271 has the same effect as setting oops=panic on the kernel command
274 This feature is useful to ensure that the kernel does not do
275 anything erroneous after an oops which could result in data
276 corruption or other issues.
280 config PANIC_ON_OOPS_VALUE
283 default 0 if !PANIC_ON_OOPS
284 default 1 if PANIC_ON_OOPS
286 config DETECT_HUNG_TASK
287 bool "Detect Hung Tasks"
288 depends on DEBUG_KERNEL
289 default LOCKUP_DETECTOR
291 Say Y here to enable the kernel to detect "hung tasks",
292 which are bugs that cause the task to be stuck in
293 uninterruptible "D" state indefinitiley.
295 When a hung task is detected, the kernel will print the
296 current stack trace (which you should report), but the
297 task will stay in uninterruptible state. If lockdep is
298 enabled then all held locks will also be reported. This
299 feature has negligible overhead.
301 config DEFAULT_HUNG_TASK_TIMEOUT
302 int "Default timeout for hung task detection (in seconds)"
303 depends on DETECT_HUNG_TASK
306 This option controls the default timeout (in seconds) used
307 to determine when a task has become non-responsive and should
310 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
311 sysctl or by writing a value to
312 /proc/sys/kernel/hung_task_timeout_secs.
314 A timeout of 0 disables the check. The default is two minutes.
315 Keeping the default should be fine in most cases.
317 config BOOTPARAM_HUNG_TASK_PANIC
318 bool "Panic (Reboot) On Hung Tasks"
319 depends on DETECT_HUNG_TASK
321 Say Y here to enable the kernel to panic on "hung tasks",
322 which are bugs that cause the kernel to leave a task stuck
323 in uninterruptible "D" state.
325 The panic can be used in combination with panic_timeout,
326 to cause the system to reboot automatically after a
327 hung task has been detected. This feature is useful for
328 high-availability systems that have uptime guarantees and
329 where a hung tasks must be resolved ASAP.
333 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
335 depends on DETECT_HUNG_TASK
337 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
338 default 1 if BOOTPARAM_HUNG_TASK_PANIC
341 bool "Collect scheduler debugging info"
342 depends on DEBUG_KERNEL && PROC_FS
345 If you say Y here, the /proc/sched_debug file will be provided
346 that can help debug the scheduler. The runtime overhead of this
350 bool "Collect scheduler statistics"
351 depends on DEBUG_KERNEL && PROC_FS
353 If you say Y here, additional code will be inserted into the
354 scheduler and related routines to collect statistics about
355 scheduler behavior and provide them in /proc/schedstat. These
356 stats may be useful for both tuning and debugging the scheduler
357 If you aren't debugging the scheduler or trying to tune a specific
358 application, you can say N to avoid the very slight overhead
362 bool "Collect kernel timers statistics"
363 depends on DEBUG_KERNEL && PROC_FS
365 If you say Y here, additional code will be inserted into the
366 timer routines to collect statistics about kernel timers being
367 reprogrammed. The statistics can be read from /proc/timer_stats.
368 The statistics collection is started by writing 1 to /proc/timer_stats,
369 writing 0 stops it. This feature is useful to collect information
370 about timer usage patterns in kernel and userspace. This feature
371 is lightweight if enabled in the kernel config but not activated
372 (it defaults to deactivated on bootup and will only be activated
373 if some application like powertop activates it explicitly).
376 bool "Debug object operations"
377 depends on DEBUG_KERNEL
379 If you say Y here, additional code will be inserted into the
380 kernel to track the life time of various objects and validate
381 the operations on those objects.
383 config DEBUG_OBJECTS_SELFTEST
384 bool "Debug objects selftest"
385 depends on DEBUG_OBJECTS
387 This enables the selftest of the object debug code.
389 config DEBUG_OBJECTS_FREE
390 bool "Debug objects in freed memory"
391 depends on DEBUG_OBJECTS
393 This enables checks whether a k/v free operation frees an area
394 which contains an object which has not been deactivated
395 properly. This can make kmalloc/kfree-intensive workloads
398 config DEBUG_OBJECTS_TIMERS
399 bool "Debug timer objects"
400 depends on DEBUG_OBJECTS
402 If you say Y here, additional code will be inserted into the
403 timer routines to track the life time of timer objects and
404 validate the timer operations.
406 config DEBUG_OBJECTS_WORK
407 bool "Debug work objects"
408 depends on DEBUG_OBJECTS
410 If you say Y here, additional code will be inserted into the
411 work queue routines to track the life time of work objects and
412 validate the work operations.
414 config DEBUG_OBJECTS_RCU_HEAD
415 bool "Debug RCU callbacks objects"
416 depends on DEBUG_OBJECTS
418 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
420 config DEBUG_OBJECTS_PERCPU_COUNTER
421 bool "Debug percpu counter objects"
422 depends on DEBUG_OBJECTS
424 If you say Y here, additional code will be inserted into the
425 percpu counter routines to track the life time of percpu counter
426 objects and validate the percpu counter operations.
428 config DEBUG_OBJECTS_ENABLE_DEFAULT
429 int "debug_objects bootup default value (0-1)"
432 depends on DEBUG_OBJECTS
434 Debug objects boot parameter default value
437 bool "Debug slab memory allocations"
438 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
440 Say Y here to have the kernel do limited verification on memory
441 allocation as well as poisoning memory on free to catch use of freed
442 memory. This can make kmalloc/kfree-intensive workloads much slower.
444 config DEBUG_SLAB_LEAK
445 bool "Memory leak debugging"
446 depends on DEBUG_SLAB
449 bool "SLUB debugging on by default"
450 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
453 Boot with debugging on by default. SLUB boots by default with
454 the runtime debug capabilities switched off. Enabling this is
455 equivalent to specifying the "slub_debug" parameter on boot.
456 There is no support for more fine grained debug control like
457 possible with slub_debug=xxx. SLUB debugging may be switched
458 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
463 bool "Enable SLUB performance statistics"
464 depends on SLUB && SYSFS
466 SLUB statistics are useful to debug SLUBs allocation behavior in
467 order find ways to optimize the allocator. This should never be
468 enabled for production use since keeping statistics slows down
469 the allocator by a few percentage points. The slabinfo command
470 supports the determination of the most active slabs to figure
471 out which slabs are relevant to a particular load.
472 Try running: slabinfo -DA
474 config HAVE_DEBUG_KMEMLEAK
477 config DEBUG_KMEMLEAK
478 bool "Kernel memory leak detector"
479 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
481 select STACKTRACE if STACKTRACE_SUPPORT
485 Say Y here if you want to enable the memory leak
486 detector. The memory allocation/freeing is traced in a way
487 similar to the Boehm's conservative garbage collector, the
488 difference being that the orphan objects are not freed but
489 only shown in /sys/kernel/debug/kmemleak. Enabling this
490 feature will introduce an overhead to memory
491 allocations. See Documentation/kmemleak.txt for more
494 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
495 of finding leaks due to the slab objects poisoning.
497 In order to access the kmemleak file, debugfs needs to be
498 mounted (usually at /sys/kernel/debug).
500 config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
501 int "Maximum kmemleak early log entries"
502 depends on DEBUG_KMEMLEAK
506 Kmemleak must track all the memory allocations to avoid
507 reporting false positives. Since memory may be allocated or
508 freed before kmemleak is initialised, an early log buffer is
509 used to store these actions. If kmemleak reports "early log
510 buffer exceeded", please increase this value.
512 config DEBUG_KMEMLEAK_TEST
513 tristate "Simple test for the kernel memory leak detector"
514 depends on DEBUG_KMEMLEAK && m
516 This option enables a module that explicitly leaks memory.
520 config DEBUG_KMEMLEAK_DEFAULT_OFF
521 bool "Default kmemleak to off"
522 depends on DEBUG_KMEMLEAK
524 Say Y here to disable kmemleak by default. It can then be enabled
525 on the command line via kmemleak=on.
527 config DEBUG_KMEMLEAK_SCAN_ON
528 bool "Enable kmemleak auto scan thread on boot up"
530 depends on DEBUG_KMEMLEAK
532 Kmemleak scan is cpu intensive and can stall user tasks at times.
533 Say N here to disable kmemleak auto scan thread at boot up.
536 bool "Debug preemptible kernel"
537 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
540 If you say Y here then the kernel will use a debug variant of the
541 commonly used smp_processor_id() function and will print warnings
542 if kernel code uses it in a preemption-unsafe way. Also, the kernel
543 will detect preemption count underflows.
545 config DEBUG_RT_MUTEXES
546 bool "RT Mutex debugging, deadlock detection"
547 depends on DEBUG_KERNEL && RT_MUTEXES
549 This allows rt mutex semantics violations and rt mutex related
550 deadlocks (lockups) to be detected and reported automatically.
555 depends on DEBUG_RT_MUTEXES
557 config RT_MUTEX_TESTER
558 bool "Built-in scriptable tester for rt-mutexes"
559 depends on DEBUG_KERNEL && RT_MUTEXES
561 This option enables a rt-mutex tester.
563 config DEBUG_SPINLOCK
564 bool "Spinlock and rw-lock debugging: basic checks"
565 depends on DEBUG_KERNEL
566 select UNINLINE_SPIN_UNLOCK
568 Say Y here and build SMP to catch missing spinlock initialization
569 and certain other kinds of spinlock errors commonly made. This is
570 best used in conjunction with the NMI watchdog so that spinlock
571 deadlocks are also debuggable.
574 bool "Mutex debugging: basic checks"
575 depends on DEBUG_KERNEL
577 This feature allows mutex semantics violations to be detected and
580 config DEBUG_LOCK_ALLOC
581 bool "Lock debugging: detect incorrect freeing of live locks"
582 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
583 select DEBUG_SPINLOCK
587 This feature will check whether any held lock (spinlock, rwlock,
588 mutex or rwsem) is incorrectly freed by the kernel, via any of the
589 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
590 vfree(), etc.), whether a live lock is incorrectly reinitialized via
591 spin_lock_init()/mutex_init()/etc., or whether there is any lock
592 held during task exit.
595 bool "Lock debugging: prove locking correctness"
596 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
598 select DEBUG_SPINLOCK
600 select DEBUG_LOCK_ALLOC
601 select TRACE_IRQFLAGS
604 This feature enables the kernel to prove that all locking
605 that occurs in the kernel runtime is mathematically
606 correct: that under no circumstance could an arbitrary (and
607 not yet triggered) combination of observed locking
608 sequences (on an arbitrary number of CPUs, running an
609 arbitrary number of tasks and interrupt contexts) cause a
612 In short, this feature enables the kernel to report locking
613 related deadlocks before they actually occur.
615 The proof does not depend on how hard and complex a
616 deadlock scenario would be to trigger: how many
617 participant CPUs, tasks and irq-contexts would be needed
618 for it to trigger. The proof also does not depend on
619 timing: if a race and a resulting deadlock is possible
620 theoretically (no matter how unlikely the race scenario
621 is), it will be proven so and will immediately be
622 reported by the kernel (once the event is observed that
623 makes the deadlock theoretically possible).
625 If a deadlock is impossible (i.e. the locking rules, as
626 observed by the kernel, are mathematically correct), the
627 kernel reports nothing.
629 NOTE: this feature can also be enabled for rwlocks, mutexes
630 and rwsems - in which case all dependencies between these
631 different locking variants are observed and mapped too, and
632 the proof of observed correctness is also maintained for an
633 arbitrary combination of these separate locking variants.
635 For more details, see Documentation/lockdep-design.txt.
639 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
641 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
646 bool "Lock usage statistics"
647 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
649 select DEBUG_SPINLOCK
651 select DEBUG_LOCK_ALLOC
654 This feature enables tracking lock contention points
656 For more details, see Documentation/lockstat.txt
658 This also enables lock events required by "perf lock",
660 If you want to use "perf lock", you also need to turn on
661 CONFIG_EVENT_TRACING.
663 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
664 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
667 bool "Lock dependency engine debugging"
668 depends on DEBUG_KERNEL && LOCKDEP
670 If you say Y here, the lock dependency engine will do
671 additional runtime checks to debug itself, at the price
672 of more runtime overhead.
674 config TRACE_IRQFLAGS
677 Enables hooks to interrupt enabling and disabling for
678 either tracing or lock debugging.
680 config DEBUG_ATOMIC_SLEEP
681 bool "Sleep inside atomic section checking"
683 depends on DEBUG_KERNEL
685 If you say Y here, various routines which may sleep will become very
686 noisy if they are called inside atomic sections: when a spinlock is
687 held, inside an rcu read side critical section, inside preempt disabled
688 sections, inside an interrupt, etc...
690 config DEBUG_LOCKING_API_SELFTESTS
691 bool "Locking API boot-time self-tests"
692 depends on DEBUG_KERNEL
694 Say Y here if you want the kernel to run a short self-test during
695 bootup. The self-test checks whether common types of locking bugs
696 are detected by debugging mechanisms or not. (if you disable
697 lock debugging then those bugs wont be detected of course.)
698 The following locking APIs are covered: spinlocks, rwlocks,
703 depends on STACKTRACE_SUPPORT
706 config DEBUG_STACK_USAGE
707 bool "Stack utilization instrumentation"
708 depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG
710 Enables the display of the minimum amount of free stack which each
711 task has ever had available in the sysrq-T and sysrq-P debug output.
713 This option will slow down process creation somewhat.
716 bool "kobject debugging"
717 depends on DEBUG_KERNEL
719 If you say Y here, some extra kobject debugging messages will be sent
723 bool "Highmem debugging"
724 depends on DEBUG_KERNEL && HIGHMEM
726 This options enables addition error checking for high memory systems.
727 Disable for production systems.
729 config HAVE_DEBUG_BUGVERBOSE
732 config DEBUG_BUGVERBOSE
733 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
734 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
737 Say Y here to make BUG() panics output the file name and line number
738 of the BUG call as well as the EIP and oops trace. This aids
739 debugging but costs about 70-100K of memory.
742 bool "Compile the kernel with debug info"
743 depends on DEBUG_KERNEL
745 If you say Y here the resulting kernel image will include
746 debugging info resulting in a larger kernel image.
747 This adds debug symbols to the kernel and modules (gcc -g), and
748 is needed if you intend to use kernel crashdump or binary object
749 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
750 Say Y here only if you plan to debug the kernel.
754 config DEBUG_INFO_REDUCED
755 bool "Reduce debugging information"
756 depends on DEBUG_INFO
758 If you say Y here gcc is instructed to generate less debugging
759 information for structure types. This means that tools that
760 need full debugging information (like kgdb or systemtap) won't
761 be happy. But if you merely need debugging information to
762 resolve line numbers there is no loss. Advantage is that
763 build directory object sizes shrink dramatically over a full
764 DEBUG_INFO build and compile times are reduced too.
765 Only works with newer gcc versions.
769 depends on DEBUG_KERNEL
771 Enable this to turn on extended checks in the virtual-memory system
772 that may impact performance.
777 bool "Debug VM red-black trees"
780 Enable this to turn on more extended checks in the virtual-memory
781 system that may impact performance.
786 bool "Debug VM translations"
787 depends on DEBUG_KERNEL && X86
789 Enable some costly sanity checks in virtual to page code. This can
790 catch mistakes with virt_to_page() and friends.
794 config DEBUG_NOMMU_REGIONS
795 bool "Debug the global anon/private NOMMU mapping region tree"
796 depends on DEBUG_KERNEL && !MMU
798 This option causes the global tree of anonymous and private mapping
799 regions to be regularly checked for invalid topology.
801 config DEBUG_WRITECOUNT
802 bool "Debug filesystem writers count"
803 depends on DEBUG_KERNEL
805 Enable this to catch wrong use of the writers count in struct
806 vfsmount. This will increase the size of each file struct by
811 config DEBUG_MEMORY_INIT
812 bool "Debug memory initialisation" if EXPERT
815 Enable this for additional checks during memory initialisation.
816 The sanity checks verify aspects of the VM such as the memory model
817 and other information provided by the architecture. Verbose
818 information will be printed at KERN_DEBUG loglevel depending
819 on the mminit_loglevel= command-line option.
824 bool "Debug linked list manipulation"
825 depends on DEBUG_KERNEL
827 Enable this to turn on extended checks in the linked-list
832 config TEST_LIST_SORT
833 bool "Linked list sorting test"
834 depends on DEBUG_KERNEL
836 Enable this to turn on 'list_sort()' function test. This test is
837 executed only once during system boot, so affects only boot time.
842 bool "Debug SG table operations"
843 depends on DEBUG_KERNEL
845 Enable this to turn on checks on scatter-gather tables. This can
846 help find problems with drivers that do not properly initialize
851 config DEBUG_NOTIFIERS
852 bool "Debug notifier call chains"
853 depends on DEBUG_KERNEL
855 Enable this to turn on sanity checking for notifier call chains.
856 This is most useful for kernel developers to make sure that
857 modules properly unregister themselves from notifier chains.
858 This is a relatively cheap check but if you care about maximum
861 config DEBUG_CREDENTIALS
862 bool "Debug credential management"
863 depends on DEBUG_KERNEL
865 Enable this to turn on some debug checking for credential
866 management. The additional code keeps track of the number of
867 pointers from task_structs to any given cred struct, and checks to
868 see that this number never exceeds the usage count of the cred
871 Furthermore, if SELinux is enabled, this also checks that the
872 security pointer in the cred struct is never seen to be invalid.
877 # Select this config option from the architecture Kconfig, if it
878 # is preferred to always offer frame pointers as a config
879 # option on the architecture (regardless of KERNEL_DEBUG):
881 config ARCH_WANT_FRAME_POINTERS
886 bool "Compile the kernel with frame pointers"
887 depends on DEBUG_KERNEL && \
888 (CRIS || M68K || FRV || UML || \
889 AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \
890 ARCH_WANT_FRAME_POINTERS
891 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
893 If you say Y here the resulting kernel image will be slightly
894 larger and slower, but it gives very useful debugging information
895 in case of kernel bugs. (precise oopses/stacktraces/warnings)
897 config BOOT_PRINTK_DELAY
898 bool "Delay each boot printk message by N milliseconds"
899 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
901 This build option allows you to read kernel boot messages
902 by inserting a short delay after each one. The delay is
903 specified in milliseconds on the kernel command line,
904 using "boot_delay=N".
906 It is likely that you would also need to use "lpj=M" to preset
907 the "loops per jiffie" value.
908 See a previous boot log for the "lpj" value to use for your
909 system, and then set "lpj=M" before setting "boot_delay=N".
910 NOTE: Using this option may adversely affect SMP systems.
911 I.e., processors other than the first one may not boot up.
912 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
913 what it believes to be lockup conditions.
918 bool "RCU debugging: prove RCU correctness"
919 depends on PROVE_LOCKING
922 This feature enables lockdep extensions that check for correct
923 use of RCU APIs. This is currently under development. Say Y
924 if you want to debug RCU usage or help work on the PROVE_RCU
927 Say N if you are unsure.
929 config PROVE_RCU_REPEATEDLY
930 bool "RCU debugging: don't disable PROVE_RCU on first splat"
934 By itself, PROVE_RCU will disable checking upon issuing the
935 first warning (or "splat"). This feature prevents such
936 disabling, allowing multiple RCU-lockdep warnings to be printed
939 Say Y to allow multiple RCU-lockdep warnings per boot.
941 Say N if you are unsure.
943 config PROVE_RCU_DELAY
944 bool "RCU debugging: preemptible RCU race provocation"
945 depends on DEBUG_KERNEL && PREEMPT_RCU
948 There is a class of races that involve an unlikely preemption
949 of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
950 been set to INT_MIN. This feature inserts a delay at that
951 point to increase the probability of these races.
953 Say Y to increase probability of preemption of __rcu_read_unlock().
955 Say N if you are unsure.
957 config SPARSE_RCU_POINTER
958 bool "RCU debugging: sparse-based checks for pointer usage"
961 This feature enables the __rcu sparse annotation for
962 RCU-protected pointers. This annotation will cause sparse
963 to flag any non-RCU used of annotated pointers. This can be
964 helpful when debugging RCU usage. Please note that this feature
965 is not intended to enforce code cleanliness; it is instead merely
968 Say Y to make sparse flag questionable use of RCU-protected pointers
970 Say N if you are unsure.
972 config RCU_TORTURE_TEST
973 tristate "torture tests for RCU"
974 depends on DEBUG_KERNEL
977 This option provides a kernel module that runs torture tests
978 on the RCU infrastructure. The kernel module may be built
979 after the fact on the running kernel to be tested, if desired.
981 Say Y here if you want RCU torture tests to be built into
983 Say M if you want the RCU torture tests to build as a module.
984 Say N if you are unsure.
986 config RCU_TORTURE_TEST_RUNNABLE
987 bool "torture tests for RCU runnable by default"
988 depends on RCU_TORTURE_TEST = y
991 This option provides a way to build the RCU torture tests
992 directly into the kernel without them starting up at boot
993 time. You can use /proc/sys/kernel/rcutorture_runnable
994 to manually override this setting. This /proc file is
995 available only when the RCU torture tests have been built
998 Say Y here if you want the RCU torture tests to start during
999 boot (you probably don't).
1000 Say N here if you want the RCU torture tests to start only
1001 after being manually enabled via /proc.
1003 config RCU_CPU_STALL_TIMEOUT
1004 int "RCU CPU stall timeout in seconds"
1005 depends on RCU_STALL_COMMON
1009 If a given RCU grace period extends more than the specified
1010 number of seconds, a CPU stall warning is printed. If the
1011 RCU grace period persists, additional CPU stall warnings are
1012 printed at more widely spaced intervals.
1014 config RCU_CPU_STALL_VERBOSE
1015 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
1016 depends on TREE_PREEMPT_RCU
1019 This option causes RCU to printk detailed per-task information
1020 for any tasks that are stalling the current RCU grace period.
1022 Say N if you are unsure.
1024 Say Y if you want to enable such checks.
1026 config RCU_CPU_STALL_INFO
1027 bool "Print additional diagnostics on RCU CPU stall"
1028 depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
1031 For each stalled CPU that is aware of the current RCU grace
1032 period, print out additional per-CPU diagnostic information
1033 regarding scheduling-clock ticks, idle state, and,
1034 for RCU_FAST_NO_HZ kernels, idle-entry state.
1036 Say N if you are unsure.
1038 Say Y if you want to enable such diagnostics.
1041 bool "Enable tracing for RCU"
1042 depends on DEBUG_KERNEL
1045 This option provides tracing in RCU which presents stats
1046 in debugfs for debugging RCU implementation.
1048 Say Y here if you want to enable RCU tracing
1049 Say N if you are unsure.
1051 endmenu # "RCU Debugging"
1053 config KPROBES_SANITY_TEST
1054 bool "Kprobes sanity tests"
1055 depends on DEBUG_KERNEL
1059 This option provides for testing basic kprobes functionality on
1060 boot. A sample kprobe, jprobe and kretprobe are inserted and
1061 verified for functionality.
1063 Say N if you are unsure.
1065 config BACKTRACE_SELF_TEST
1066 tristate "Self test for the backtrace code"
1067 depends on DEBUG_KERNEL
1070 This option provides a kernel module that can be used to test
1071 the kernel stack backtrace code. This option is not useful
1072 for distributions or general kernels, but only for kernel
1073 developers working on architecture code.
1075 Note that if you want to also test saved backtraces, you will
1076 have to enable STACKTRACE as well.
1078 Say N if you are unsure.
1080 config DEBUG_BLOCK_EXT_DEVT
1081 bool "Force extended block device numbers and spread them"
1082 depends on DEBUG_KERNEL
1086 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1087 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1088 YOU ARE DOING. Distros, please enable this and fix whatever
1091 Conventionally, block device numbers are allocated from
1092 predetermined contiguous area. However, extended block area
1093 may introduce non-contiguous block device numbers. This
1094 option forces most block device numbers to be allocated from
1095 the extended space and spreads them to discover kernel or
1096 userland code paths which assume predetermined contiguous
1097 device number allocation.
1099 Note that turning on this debug option shuffles all the
1100 device numbers for all IDE and SCSI devices including libata
1101 ones, so root partition specified using device number
1102 directly (via rdev or root=MAJ:MIN) won't work anymore.
1103 Textual device names (root=/dev/sdXn) will continue to work.
1105 Say N if you are unsure.
1107 config DEBUG_FORCE_WEAK_PER_CPU
1108 bool "Force weak per-cpu definitions"
1109 depends on DEBUG_KERNEL
1111 s390 and alpha require percpu variables in modules to be
1112 defined weak to work around addressing range issue which
1113 puts the following two restrictions on percpu variable
1116 1. percpu symbols must be unique whether static or not
1117 2. percpu variables can't be defined inside a function
1119 To ensure that generic code follows the above rules, this
1120 option forces all percpu variables to be defined as weak.
1122 config DEBUG_PER_CPU_MAPS
1123 bool "Debug access to per_cpu maps"
1124 depends on DEBUG_KERNEL
1127 Say Y to verify that the per_cpu map being accessed has
1128 been set up. This adds a fair amount of code to kernel memory
1129 and decreases performance.
1134 tristate "Linux Kernel Dump Test Tool Module"
1139 This module enables testing of the different dumping mechanisms by
1140 inducing system failures at predefined crash points.
1141 If you don't need it: say N
1142 Choose M here to compile this code as a module. The module will be
1145 Documentation on how to use the module can be found in
1146 Documentation/fault-injection/provoke-crashes.txt
1148 config NOTIFIER_ERROR_INJECTION
1149 tristate "Notifier error injection"
1150 depends on DEBUG_KERNEL
1153 This option provides the ability to inject artificial errors to
1154 specified notifier chain callbacks. It is useful to test the error
1155 handling of notifier call chain failures.
1159 config CPU_NOTIFIER_ERROR_INJECT
1160 tristate "CPU notifier error injection module"
1161 depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
1163 This option provides a kernel module that can be used to test
1164 the error handling of the cpu notifiers by injecting artificial
1165 errors to CPU notifier chain callbacks. It is controlled through
1166 debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu
1168 If the notifier call chain should be failed with some events
1169 notified, write the error code to "actions/<notifier event>/error".
1171 Example: Inject CPU offline error (-1 == -EPERM)
1173 # cd /sys/kernel/debug/notifier-error-inject/cpu
1174 # echo -1 > actions/CPU_DOWN_PREPARE/error
1175 # echo 0 > /sys/devices/system/cpu/cpu1/online
1176 bash: echo: write error: Operation not permitted
1178 To compile this code as a module, choose M here: the module will
1179 be called cpu-notifier-error-inject.
1183 config PM_NOTIFIER_ERROR_INJECT
1184 tristate "PM notifier error injection module"
1185 depends on PM && NOTIFIER_ERROR_INJECTION
1186 default m if PM_DEBUG
1188 This option provides the ability to inject artificial errors to
1189 PM notifier chain callbacks. It is controlled through debugfs
1190 interface /sys/kernel/debug/notifier-error-inject/pm
1192 If the notifier call chain should be failed with some events
1193 notified, write the error code to "actions/<notifier event>/error".
1195 Example: Inject PM suspend error (-12 = -ENOMEM)
1197 # cd /sys/kernel/debug/notifier-error-inject/pm/
1198 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1199 # echo mem > /sys/power/state
1200 bash: echo: write error: Cannot allocate memory
1202 To compile this code as a module, choose M here: the module will
1203 be called pm-notifier-error-inject.
1207 config MEMORY_NOTIFIER_ERROR_INJECT
1208 tristate "Memory hotplug notifier error injection module"
1209 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
1211 This option provides the ability to inject artificial errors to
1212 memory hotplug notifier chain callbacks. It is controlled through
1213 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
1215 If the notifier call chain should be failed with some events
1216 notified, write the error code to "actions/<notifier event>/error".
1218 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
1220 # cd /sys/kernel/debug/notifier-error-inject/memory
1221 # echo -12 > actions/MEM_GOING_OFFLINE/error
1222 # echo offline > /sys/devices/system/memory/memoryXXX/state
1223 bash: echo: write error: Cannot allocate memory
1225 To compile this code as a module, choose M here: the module will
1226 be called memory-notifier-error-inject.
1230 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1231 tristate "OF reconfig notifier error injection module"
1232 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1234 This option provides the ability to inject artificial errors to
1235 OF reconfig notifier chain callbacks. It is controlled
1236 through debugfs interface under
1237 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1239 If the notifier call chain should be failed with some events
1240 notified, write the error code to "actions/<notifier event>/error".
1242 To compile this code as a module, choose M here: the module will
1243 be called of-reconfig-notifier-error-inject.
1247 config FAULT_INJECTION
1248 bool "Fault-injection framework"
1249 depends on DEBUG_KERNEL
1251 Provide fault-injection framework.
1252 For more details, see Documentation/fault-injection/.
1255 bool "Fault-injection capability for kmalloc"
1256 depends on FAULT_INJECTION
1257 depends on SLAB || SLUB
1259 Provide fault-injection capability for kmalloc.
1261 config FAIL_PAGE_ALLOC
1262 bool "Fault-injection capabilitiy for alloc_pages()"
1263 depends on FAULT_INJECTION
1265 Provide fault-injection capability for alloc_pages().
1267 config FAIL_MAKE_REQUEST
1268 bool "Fault-injection capability for disk IO"
1269 depends on FAULT_INJECTION && BLOCK
1271 Provide fault-injection capability for disk IO.
1273 config FAIL_IO_TIMEOUT
1274 bool "Fault-injection capability for faking disk interrupts"
1275 depends on FAULT_INJECTION && BLOCK
1277 Provide fault-injection capability on end IO handling. This
1278 will make the block layer "forget" an interrupt as configured,
1279 thus exercising the error handling.
1281 Only works with drivers that use the generic timeout handling,
1282 for others it wont do anything.
1284 config FAIL_MMC_REQUEST
1285 bool "Fault-injection capability for MMC IO"
1287 depends on FAULT_INJECTION && MMC
1289 Provide fault-injection capability for MMC IO.
1290 This will make the mmc core return data errors. This is
1291 useful to test the error handling in the mmc block device
1292 and to test how the mmc host driver handles retries from
1295 config FAULT_INJECTION_DEBUG_FS
1296 bool "Debugfs entries for fault-injection capabilities"
1297 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1299 Enable configuration of fault-injection capabilities via debugfs.
1301 config FAULT_INJECTION_STACKTRACE_FILTER
1302 bool "stacktrace filter for fault-injection capabilities"
1303 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1306 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
1308 Provide stacktrace filter for fault-injection capabilities
1311 bool "Latency measuring infrastructure"
1312 depends on HAVE_LATENCYTOP_SUPPORT
1313 depends on DEBUG_KERNEL
1314 depends on STACKTRACE_SUPPORT
1316 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
1323 Enable this option if you want to use the LatencyTOP tool
1324 to find out which userspace is blocking on what kernel operations.
1326 config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1329 config DEBUG_STRICT_USER_COPY_CHECKS
1330 bool "Strict user copy size checks"
1331 depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1332 depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING
1334 Enabling this option turns a certain set of sanity checks for user
1335 copy operations into compile time failures.
1337 The copy_from_user() etc checks are there to help test if there
1338 are sufficient security checks on the length argument of
1339 the copy operation, by having gcc prove that the argument is
1344 source mm/Kconfig.debug
1345 source kernel/trace/Kconfig
1348 tristate "Red-Black tree test"
1349 depends on m && DEBUG_KERNEL
1351 A benchmark measuring the performance of the rbtree library.
1352 Also includes rbtree invariant checks.
1354 config INTERVAL_TREE_TEST
1355 tristate "Interval tree test"
1356 depends on m && DEBUG_KERNEL
1358 A benchmark measuring the performance of the interval tree library
1360 config PROVIDE_OHCI1394_DMA_INIT
1361 bool "Remote debugging over FireWire early on boot"
1362 depends on PCI && X86
1364 If you want to debug problems which hang or crash the kernel early
1365 on boot and the crashing machine has a FireWire port, you can use
1366 this feature to remotely access the memory of the crashed machine
1367 over FireWire. This employs remote DMA as part of the OHCI1394
1368 specification which is now the standard for FireWire controllers.
1370 With remote DMA, you can monitor the printk buffer remotely using
1371 firescope and access all memory below 4GB using fireproxy from gdb.
1372 Even controlling a kernel debugger is possible using remote DMA.
1376 If ohci1394_dma=early is used as boot parameter, it will initialize
1377 all OHCI1394 controllers which are found in the PCI config space.
1379 As all changes to the FireWire bus such as enabling and disabling
1380 devices cause a bus reset and thereby disable remote DMA for all
1381 devices, be sure to have the cable plugged and FireWire enabled on
1382 the debugging host before booting the debug target for debugging.
1384 This code (~1k) is freed after boot. By then, the firewire stack
1385 in charge of the OHCI-1394 controllers should be used instead.
1387 See Documentation/debugging-via-ohci1394.txt for more information.
1389 config FIREWIRE_OHCI_REMOTE_DMA
1390 bool "Remote debugging over FireWire with firewire-ohci"
1391 depends on FIREWIRE_OHCI
1393 This option lets you use the FireWire bus for remote debugging
1394 with help of the firewire-ohci driver. It enables unfiltered
1395 remote DMA in firewire-ohci.
1396 See Documentation/debugging-via-ohci1394.txt for more information.
1401 bool "Build targets in Documentation/ tree"
1402 depends on HEADERS_CHECK
1404 This option attempts to build objects from the source files in the
1405 kernel Documentation/ tree.
1407 Say N if you are unsure.
1409 config DYNAMIC_DEBUG
1410 bool "Enable dynamic printk() support"
1416 Compiles debug level messages into the kernel, which would not
1417 otherwise be available at runtime. These messages can then be
1418 enabled/disabled based on various levels of scope - per source file,
1419 function, module, format string, and line number. This mechanism
1420 implicitly compiles in all pr_debug() and dev_dbg() calls, which
1421 enlarges the kernel text size by about 2%.
1423 If a source file is compiled with DEBUG flag set, any
1424 pr_debug() calls in it are enabled by default, but can be
1425 disabled at runtime as below. Note that DEBUG flag is
1426 turned on by many CONFIG_*DEBUG* options.
1430 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
1431 which is contained in the 'debugfs' filesystem. Thus, the debugfs
1432 filesystem must first be mounted before making use of this feature.
1433 We refer the control file as: <debugfs>/dynamic_debug/control. This
1434 file contains a list of the debug statements that can be enabled. The
1435 format for each line of the file is:
1437 filename:lineno [module]function flags format
1439 filename : source file of the debug statement
1440 lineno : line number of the debug statement
1441 module : module that contains the debug statement
1442 function : function that contains the debug statement
1443 flags : '=p' means the line is turned 'on' for printing
1444 format : the format used for the debug statement
1448 nullarbor:~ # cat <debugfs>/dynamic_debug/control
1449 # filename:lineno [module]function flags format
1450 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
1451 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
1452 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
1456 // enable the message at line 1603 of file svcsock.c
1457 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
1458 <debugfs>/dynamic_debug/control
1460 // enable all the messages in file svcsock.c
1461 nullarbor:~ # echo -n 'file svcsock.c +p' >
1462 <debugfs>/dynamic_debug/control
1464 // enable all the messages in the NFS server module
1465 nullarbor:~ # echo -n 'module nfsd +p' >
1466 <debugfs>/dynamic_debug/control
1468 // enable all 12 messages in the function svc_process()
1469 nullarbor:~ # echo -n 'func svc_process +p' >
1470 <debugfs>/dynamic_debug/control
1472 // disable all 12 messages in the function svc_process()
1473 nullarbor:~ # echo -n 'func svc_process -p' >
1474 <debugfs>/dynamic_debug/control
1476 See Documentation/dynamic-debug-howto.txt for additional information.
1478 config DMA_API_DEBUG
1479 bool "Enable debugging of DMA-API usage"
1480 depends on HAVE_DMA_API_DEBUG
1482 Enable this option to debug the use of the DMA API by device drivers.
1483 With this option you will be able to detect common bugs in device
1484 drivers like double-freeing of DMA mappings or freeing mappings that
1485 were never allocated.
1486 This option causes a performance degredation. Use only if you want
1487 to debug device drivers. If unsure, say N.
1489 config ATOMIC64_SELFTEST
1490 bool "Perform an atomic64_t self-test at boot"
1492 Enable this option to test the atomic64_t functions at boot.
1496 config ASYNC_RAID6_TEST
1497 tristate "Self test for hardware accelerated raid6 recovery"
1498 depends on ASYNC_RAID6_RECOV
1501 This is a one-shot self test that permutes through the
1502 recovery of all the possible two disk failure scenarios for a
1503 N-disk array. Recovery is performed with the asynchronous
1504 raid6 recovery routines, and will optionally use an offload
1505 engine if one is available.
1509 source "samples/Kconfig"
1511 source "lib/Kconfig.kgdb"
1513 source "lib/Kconfig.kmemcheck"
1515 config TEST_STRING_HELPERS
1516 tristate "Test functions located in the string_helpers module at runtime"
1519 tristate "Test kstrto*() family of functions at runtime"