| blob | 6fdead79ee15562270b7c67f7d44e2c73c9965b8 |
2 config PRINTK_TIME
3 bool "Show timing information on printks"
4 depends on PRINTK
5 help
6 Selecting this option causes time stamps of the printk()
7 messages to be added to the output of the syslog() system
8 call and at the console.
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)"
19 range 1 7
20 default "4"
21 help
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
26 priority.
28 config ENABLE_WARN_DEPRECATED
29 bool "Enable __deprecated logic"
30 default y
31 help
32 Enable the __deprecated logic in the kernel build.
33 Disable this to suppress the "warning: 'foo' is deprecated
34 (declared at kernel/power/somefile.c:1234)" messages.
36 config ENABLE_MUST_CHECK
37 bool "Enable __must_check logic"
38 default y
39 help
40 Enable the __must_check logic in the kernel build. Disable this to
41 suppress the "warning: ignoring return value of 'foo', declared with
42 attribute warn_unused_result" messages.
44 config FRAME_WARN
45 int "Warn for stack frames larger than (needs gcc 4.4)"
46 range 0 8192
47 default 1024 if !64BIT
48 default 2048 if 64BIT
49 help
50 Tell gcc to warn at build time for stack frames larger than this.
51 Setting this too low will cause a lot of warnings.
52 Setting it to 0 disables the warning.
53 Requires gcc 4.4
55 config MAGIC_SYSRQ
56 bool "Magic SysRq key"
57 depends on !UML
58 help
59 If you say Y here, you will have some control over the system even
60 if the system crashes for example during kernel debugging (e.g., you
61 will be able to flush the buffer cache to disk, reboot the system
62 immediately or dump some status information). This is accomplished
63 by pressing various keys while holding SysRq (Alt+PrintScreen). It
64 also works on a serial console (on PC hardware at least), if you
65 send a BREAK and then within 5 seconds a command keypress. The
66 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
67 unless you really know what this hack does.
69 config STRIP_ASM_SYMS
70 bool "Strip assembler-generated symbols during link"
71 default n
72 help
73 Strip internal assembler-generated symbols during a link (symbols
74 that look like '.Lxxx') so they don't pollute the output of
75 get_wchan() and suchlike.
77 config READABLE_ASM
78 bool "Generate readable assembler code"
79 depends on DEBUG_KERNEL
80 help
81 Disable some compiler optimizations that tend to generate human unreadable
82 assembler output. This may make the kernel slightly slower, but it helps
83 to keep kernel developers who have to stare a lot at assembler listings
84 sane.
86 config UNUSED_SYMBOLS
87 bool "Enable unused/obsolete exported symbols"
88 default y if X86
89 help
90 Unused but exported symbols make the kernel needlessly bigger. For
91 that reason most of these unused exports will soon be removed. This
92 option is provided temporarily to provide a transition period in case
93 some external kernel module needs one of these symbols anyway. If you
94 encounter such a case in your module, consider if you are actually
95 using the right API. (rationale: since nobody in the kernel is using
96 this in a module, there is a pretty good chance it's actually the
97 wrong interface to use). If you really need the symbol, please send a
98 mail to the linux kernel mailing list mentioning the symbol and why
99 you really need it, and what the merge plan to the mainline kernel for
100 your module is.
102 config DEBUG_FS
103 bool "Debug Filesystem"
104 help
105 debugfs is a virtual file system that kernel developers use to put
106 debugging files into. Enable this option to be able to read and
107 write to these files.
109 For detailed documentation on the debugfs API, see
110 Documentation/DocBook/filesystems.
112 If unsure, say N.
114 config HEADERS_CHECK
115 bool "Run 'make headers_check' when building vmlinux"
116 depends on !UML
117 help
118 This option will extract the user-visible kernel headers whenever
119 building the kernel, and will run basic sanity checks on them to
120 ensure that exported files do not attempt to include files which
121 were not exported, etc.
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"
130 help
131 The section mismatch analysis checks if there are illegal
132 references from one section to another section.
133 During linktime or runtime, some sections are dropped;
134 any use of code/data previously in these sections would
135 most likely result in an oops.
136 In the code, functions and variables are annotated with
137 __init, __cpuinit, etc. (see the full list in include/linux/init.h),
138 which results in the code/data being placed in specific sections.
139 The section mismatch analysis is always performed after a full
140 kernel build, and enabling this option causes the following
141 additional steps to occur:
142 - Add the option -fno-inline-functions-called-once to gcc commands.
143 When inlining a function annotated with __init in a non-init
144 function, we would lose the section information and thus
145 the analysis would not catch the illegal reference.
146 This option tells gcc to inline less (but it does result in
147 a larger kernel).
148 - Run the section mismatch analysis for each module/built-in.o file.
149 When we run the section mismatch analysis on vmlinux.o, we
150 lose valueble information about where the mismatch was
151 introduced.
152 Running the analysis for each module/built-in.o file
153 tells where the mismatch happens much closer to the
154 source. The drawback is that the same mismatch is
155 reported at least twice.
156 - Enable verbose reporting from modpost in order to help resolve
157 the section mismatches that are reported.
159 config DEBUG_KERNEL
160 bool "Kernel debugging"
161 help
162 Say Y here if you are developing drivers or trying to debug and
163 identify kernel problems.
165 menu "Memory Debugging"
167 source mm/Kconfig.debug
169 config DEBUG_OBJECTS
170 bool "Debug object operations"
171 depends on DEBUG_KERNEL
172 help
173 If you say Y here, additional code will be inserted into the
174 kernel to track the life time of various objects and validate
175 the operations on those objects.
177 config DEBUG_OBJECTS_SELFTEST
178 bool "Debug objects selftest"
179 depends on DEBUG_OBJECTS
180 help
181 This enables the selftest of the object debug code.
183 config DEBUG_OBJECTS_FREE
184 bool "Debug objects in freed memory"
185 depends on DEBUG_OBJECTS
186 help
187 This enables checks whether a k/v free operation frees an area
188 which contains an object which has not been deactivated
189 properly. This can make kmalloc/kfree-intensive workloads
190 much slower.
192 config DEBUG_OBJECTS_TIMERS
193 bool "Debug timer objects"
194 depends on DEBUG_OBJECTS
195 help
196 If you say Y here, additional code will be inserted into the
197 timer routines to track the life time of timer objects and
198 validate the timer operations.
200 config DEBUG_OBJECTS_WORK
201 bool "Debug work objects"
202 depends on DEBUG_OBJECTS
203 help
204 If you say Y here, additional code will be inserted into the
205 work queue routines to track the life time of work objects and
206 validate the work operations.
208 config DEBUG_OBJECTS_RCU_HEAD
209 bool "Debug RCU callbacks objects"
210 depends on DEBUG_OBJECTS
211 help
212 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
214 config DEBUG_OBJECTS_PERCPU_COUNTER
215 bool "Debug percpu counter objects"
216 depends on DEBUG_OBJECTS
217 help
218 If you say Y here, additional code will be inserted into the
219 percpu counter routines to track the life time of percpu counter
220 objects and validate the percpu counter operations.
222 config DEBUG_OBJECTS_ENABLE_DEFAULT
223 int "debug_objects bootup default value (0-1)"
224 range 0 1
225 default "1"
226 depends on DEBUG_OBJECTS
227 help
228 Debug objects boot parameter default value
230 config DEBUG_SLAB
231 bool "Debug slab memory allocations"
232 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
233 help
234 Say Y here to have the kernel do limited verification on memory
235 allocation as well as poisoning memory on free to catch use of freed
236 memory. This can make kmalloc/kfree-intensive workloads much slower.
238 config DEBUG_SLAB_LEAK
239 bool "Memory leak debugging"
240 depends on DEBUG_SLAB
242 config SLUB_DEBUG_ON
243 bool "SLUB debugging on by default"
244 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
245 default n
246 help
247 Boot with debugging on by default. SLUB boots by default with
248 the runtime debug capabilities switched off. Enabling this is
249 equivalent to specifying the "slub_debug" parameter on boot.
250 There is no support for more fine grained debug control like
251 possible with slub_debug=xxx. SLUB debugging may be switched
252 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
253 "slub_debug=-".
255 config SLUB_STATS
256 default n
257 bool "Enable SLUB performance statistics"
258 depends on SLUB && SYSFS
259 help
260 SLUB statistics are useful to debug SLUBs allocation behavior in
261 order find ways to optimize the allocator. This should never be
262 enabled for production use since keeping statistics slows down
263 the allocator by a few percentage points. The slabinfo command
264 supports the determination of the most active slabs to figure
265 out which slabs are relevant to a particular load.
266 Try running: slabinfo -DA
268 config HAVE_DEBUG_KMEMLEAK
269 bool
271 config DEBUG_KMEMLEAK
272 bool "Kernel memory leak detector"
273 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
274 select DEBUG_FS
275 select STACKTRACE if STACKTRACE_SUPPORT
276 select KALLSYMS
277 select CRC32
278 help
279 Say Y here if you want to enable the memory leak
280 detector. The memory allocation/freeing is traced in a way
281 similar to the Boehm's conservative garbage collector, the
282 difference being that the orphan objects are not freed but
283 only shown in /sys/kernel/debug/kmemleak. Enabling this
284 feature will introduce an overhead to memory
285 allocations. See Documentation/kmemleak.txt for more
286 details.
288 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
289 of finding leaks due to the slab objects poisoning.
291 In order to access the kmemleak file, debugfs needs to be
292 mounted (usually at /sys/kernel/debug).
294 config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
295 int "Maximum kmemleak early log entries"
296 depends on DEBUG_KMEMLEAK
297 range 200 40000
298 default 400
299 help
300 Kmemleak must track all the memory allocations to avoid
301 reporting false positives. Since memory may be allocated or
302 freed before kmemleak is initialised, an early log buffer is
303 used to store these actions. If kmemleak reports "early log
304 buffer exceeded", please increase this value.
306 config DEBUG_KMEMLEAK_TEST
307 tristate "Simple test for the kernel memory leak detector"
308 depends on DEBUG_KMEMLEAK && m
309 help
310 This option enables a module that explicitly leaks memory.
312 If unsure, say N.
314 config DEBUG_KMEMLEAK_DEFAULT_OFF
315 bool "Default kmemleak to off"
316 depends on DEBUG_KMEMLEAK
317 help
318 Say Y here to disable kmemleak by default. It can then be enabled
319 on the command line via kmemleak=on.
321 config DEBUG_STACK_USAGE
322 bool "Stack utilization instrumentation"
323 depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG
324 help
325 Enables the display of the minimum amount of free stack which each
326 task has ever had available in the sysrq-T and sysrq-P debug output.
328 This option will slow down process creation somewhat.
330 config DEBUG_VM
331 bool "Debug VM"
332 depends on DEBUG_KERNEL
333 help
334 Enable this to turn on extended checks in the virtual-memory system
335 that may impact performance.
337 If unsure, say N.
339 config DEBUG_VM_RB
340 bool "Debug VM red-black trees"
341 depends on DEBUG_VM
342 help
343 Enable this to turn on more extended checks in the virtual-memory
344 system that may impact performance.
346 If unsure, say N.
348 config DEBUG_VIRTUAL
349 bool "Debug VM translations"
350 depends on DEBUG_KERNEL && X86
351 help
352 Enable some costly sanity checks in virtual to page code. This can
353 catch mistakes with virt_to_page() and friends.
355 If unsure, say N.
357 config DEBUG_NOMMU_REGIONS
358 bool "Debug the global anon/private NOMMU mapping region tree"
359 depends on DEBUG_KERNEL && !MMU
360 help
361 This option causes the global tree of anonymous and private mapping
362 regions to be regularly checked for invalid topology.
364 config DEBUG_MEMORY_INIT
365 bool "Debug memory initialisation" if EXPERT
366 default !EXPERT
367 help
368 Enable this for additional checks during memory initialisation.
369 The sanity checks verify aspects of the VM such as the memory model
370 and other information provided by the architecture. Verbose
371 information will be printed at KERN_DEBUG loglevel depending
372 on the mminit_loglevel= command-line option.
374 If unsure, say Y
376 config MEMORY_NOTIFIER_ERROR_INJECT
377 tristate "Memory hotplug notifier error injection module"
378 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
379 help
380 This option provides the ability to inject artificial errors to
381 memory hotplug notifier chain callbacks. It is controlled through
382 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
384 If the notifier call chain should be failed with some events
385 notified, write the error code to "actions/<notifier event>/error".
387 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
389 # cd /sys/kernel/debug/notifier-error-inject/memory
390 # echo -12 > actions/MEM_GOING_OFFLINE/error
391 # echo offline > /sys/devices/system/memory/memoryXXX/state
392 bash: echo: write error: Cannot allocate memory
394 To compile this code as a module, choose M here: the module will
395 be called memory-notifier-error-inject.
397 If unsure, say N.
399 config DEBUG_PER_CPU_MAPS
400 bool "Debug access to per_cpu maps"
401 depends on DEBUG_KERNEL
402 depends on SMP
403 help
404 Say Y to verify that the per_cpu map being accessed has
405 been set up. This adds a fair amount of code to kernel memory
406 and decreases performance.
408 Say N if unsure.
410 config DEBUG_HIGHMEM
411 bool "Highmem debugging"
412 depends on DEBUG_KERNEL && HIGHMEM
413 help
414 This options enables addition error checking for high memory systems.
415 Disable for production systems.
417 config HAVE_DEBUG_STACKOVERFLOW
418 bool
420 config DEBUG_STACKOVERFLOW
421 bool "Check for stack overflows"
422 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
423 ---help---
424 Say Y here if you want to check for overflows of kernel, IRQ
425 and exception stacks (if your archicture uses them). This
426 option will show detailed messages if free stack space drops
427 below a certain limit.
429 These kinds of bugs usually occur when call-chains in the
430 kernel get too deep, especially when interrupts are
431 involved.
433 Use this in cases where you see apparently random memory
434 corruption, especially if it appears in 'struct thread_info'
436 If in doubt, say "N".
438 source "lib/Kconfig.kmemcheck"
440 endmenu # "Memory Debugging"
442 config DEBUG_SHIRQ
443 bool "Debug shared IRQ handlers"
444 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
445 help
446 Enable this to generate a spurious interrupt as soon as a shared
447 interrupt handler is registered, and just before one is deregistered.
448 Drivers ought to be able to handle interrupts coming in at those
449 points; some don't and need to be caught.
451 config LOCKUP_DETECTOR
452 bool "Detect Hard and Soft Lockups"
453 depends on DEBUG_KERNEL && !S390
454 help
455 Say Y here to enable the kernel to act as a watchdog to detect
456 hard and soft lockups.
458 Softlockups are bugs that cause the kernel to loop in kernel
459 mode for more than 20 seconds, without giving other tasks a
460 chance to run. The current stack trace is displayed upon
461 detection and the system will stay locked up.
463 Hardlockups are bugs that cause the CPU to loop in kernel mode
464 for more than 10 seconds, without letting other interrupts have a
465 chance to run. The current stack trace is displayed upon detection
466 and the system will stay locked up.
468 The overhead should be minimal. A periodic hrtimer runs to
469 generate interrupts and kick the watchdog task every 4 seconds.
470 An NMI is generated every 10 seconds or so to check for hardlockups.
472 The frequency of hrtimer and NMI events and the soft and hard lockup
473 thresholds can be controlled through the sysctl watchdog_thresh.
475 config HARDLOCKUP_DETECTOR
476 def_bool y
477 depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG
478 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
480 config BOOTPARAM_HARDLOCKUP_PANIC
481 bool "Panic (Reboot) On Hard Lockups"
482 depends on HARDLOCKUP_DETECTOR
483 help
484 Say Y here to enable the kernel to panic on "hard lockups",
485 which are bugs that cause the kernel to loop in kernel
486 mode with interrupts disabled for more than 10 seconds (configurable
487 using the watchdog_thresh sysctl).
489 Say N if unsure.
491 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
492 int
493 depends on HARDLOCKUP_DETECTOR
494 range 0 1
495 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
496 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
498 config BOOTPARAM_SOFTLOCKUP_PANIC
499 bool "Panic (Reboot) On Soft Lockups"
500 depends on LOCKUP_DETECTOR
501 help
502 Say Y here to enable the kernel to panic on "soft lockups",
503 which are bugs that cause the kernel to loop in kernel
504 mode for more than 20 seconds (configurable using the watchdog_thresh
505 sysctl), without giving other tasks a chance to run.
507 The panic can be used in combination with panic_timeout,
508 to cause the system to reboot automatically after a
509 lockup has been detected. This feature is useful for
510 high-availability systems that have uptime guarantees and
511 where a lockup must be resolved ASAP.
513 Say N if unsure.
515 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
516 int
517 depends on LOCKUP_DETECTOR
518 range 0 1
519 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
520 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
522 config PANIC_ON_OOPS
523 bool "Panic on Oops"
524 help
525 Say Y here to enable the kernel to panic when it oopses. This
526 has the same effect as setting oops=panic on the kernel command
527 line.
529 This feature is useful to ensure that the kernel does not do
530 anything erroneous after an oops which could result in data
531 corruption or other issues.
533 Say N if unsure.
535 config PANIC_ON_OOPS_VALUE
536 int
537 range 0 1
538 default 0 if !PANIC_ON_OOPS
539 default 1 if PANIC_ON_OOPS
541 config DETECT_HUNG_TASK
542 bool "Detect Hung Tasks"
543 depends on DEBUG_KERNEL
544 default LOCKUP_DETECTOR
545 help
546 Say Y here to enable the kernel to detect "hung tasks",
547 which are bugs that cause the task to be stuck in
548 uninterruptible "D" state indefinitiley.
550 When a hung task is detected, the kernel will print the
551 current stack trace (which you should report), but the
552 task will stay in uninterruptible state. If lockdep is
553 enabled then all held locks will also be reported. This
554 feature has negligible overhead.
556 config DEFAULT_HUNG_TASK_TIMEOUT
557 int "Default timeout for hung task detection (in seconds)"
558 depends on DETECT_HUNG_TASK
559 default 120
560 help
561 This option controls the default timeout (in seconds) used
562 to determine when a task has become non-responsive and should
563 be considered hung.
565 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
566 sysctl or by writing a value to
567 /proc/sys/kernel/hung_task_timeout_secs.
569 A timeout of 0 disables the check. The default is two minutes.
570 Keeping the default should be fine in most cases.
572 config BOOTPARAM_HUNG_TASK_PANIC
573 bool "Panic (Reboot) On Hung Tasks"
574 depends on DETECT_HUNG_TASK
575 help
576 Say Y here to enable the kernel to panic on "hung tasks",
577 which are bugs that cause the kernel to leave a task stuck
578 in uninterruptible "D" state.
580 The panic can be used in combination with panic_timeout,
581 to cause the system to reboot automatically after a
582 hung task has been detected. This feature is useful for
583 high-availability systems that have uptime guarantees and
584 where a hung tasks must be resolved ASAP.
586 Say N if unsure.
588 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
589 int
590 depends on DETECT_HUNG_TASK
591 range 0 1
592 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
593 default 1 if BOOTPARAM_HUNG_TASK_PANIC
595 config SCHED_DEBUG
596 bool "Collect scheduler debugging info"
597 depends on DEBUG_KERNEL && PROC_FS
598 default y
599 help
600 If you say Y here, the /proc/sched_debug file will be provided
601 that can help debug the scheduler. The runtime overhead of this
602 option is minimal.
604 config SCHEDSTATS
605 bool "Collect scheduler statistics"
606 depends on DEBUG_KERNEL && PROC_FS
607 help
608 If you say Y here, additional code will be inserted into the
609 scheduler and related routines to collect statistics about
610 scheduler behavior and provide them in /proc/schedstat. These
611 stats may be useful for both tuning and debugging the scheduler
612 If you aren't debugging the scheduler or trying to tune a specific
613 application, you can say N to avoid the very slight overhead
614 this adds.
616 config TIMER_STATS
617 bool "Collect kernel timers statistics"
618 depends on DEBUG_KERNEL && PROC_FS
619 help
620 If you say Y here, additional code will be inserted into the
621 timer routines to collect statistics about kernel timers being
622 reprogrammed. The statistics can be read from /proc/timer_stats.
623 The statistics collection is started by writing 1 to /proc/timer_stats,
624 writing 0 stops it. This feature is useful to collect information
625 about timer usage patterns in kernel and userspace. This feature
626 is lightweight if enabled in the kernel config but not activated
627 (it defaults to deactivated on bootup and will only be activated
628 if some application like powertop activates it explicitly).
630 config DEBUG_PREEMPT
631 bool "Debug preemptible kernel"
632 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
633 default y
634 help
635 If you say Y here then the kernel will use a debug variant of the
636 commonly used smp_processor_id() function and will print warnings
637 if kernel code uses it in a preemption-unsafe way. Also, the kernel
638 will detect preemption count underflows.
640 config DEBUG_RT_MUTEXES
641 bool "RT Mutex debugging, deadlock detection"
642 depends on DEBUG_KERNEL && RT_MUTEXES
643 help
644 This allows rt mutex semantics violations and rt mutex related
645 deadlocks (lockups) to be detected and reported automatically.
647 config DEBUG_PI_LIST
648 bool
649 default y
650 depends on DEBUG_RT_MUTEXES
652 config RT_MUTEX_TESTER
653 bool "Built-in scriptable tester for rt-mutexes"
654 depends on DEBUG_KERNEL && RT_MUTEXES
655 help
656 This option enables a rt-mutex tester.
658 config DEBUG_SPINLOCK
659 bool "Spinlock and rw-lock debugging: basic checks"
660 depends on DEBUG_KERNEL
661 select UNINLINE_SPIN_UNLOCK
662 help
663 Say Y here and build SMP to catch missing spinlock initialization
664 and certain other kinds of spinlock errors commonly made. This is
665 best used in conjunction with the NMI watchdog so that spinlock
666 deadlocks are also debuggable.
668 config DEBUG_MUTEXES
669 bool "Mutex debugging: basic checks"
670 depends on DEBUG_KERNEL
671 help
672 This feature allows mutex semantics violations to be detected and
673 reported.
675 config DEBUG_LOCK_ALLOC
676 bool "Lock debugging: detect incorrect freeing of live locks"
677 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
678 select DEBUG_SPINLOCK
679 select DEBUG_MUTEXES
680 select LOCKDEP
681 help
682 This feature will check whether any held lock (spinlock, rwlock,
683 mutex or rwsem) is incorrectly freed by the kernel, via any of the
684 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
685 vfree(), etc.), whether a live lock is incorrectly reinitialized via
686 spin_lock_init()/mutex_init()/etc., or whether there is any lock
687 held during task exit.
689 config PROVE_LOCKING
690 bool "Lock debugging: prove locking correctness"
691 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
692 select LOCKDEP
693 select DEBUG_SPINLOCK
694 select DEBUG_MUTEXES
695 select DEBUG_LOCK_ALLOC
696 select TRACE_IRQFLAGS
697 default n
698 help
699 This feature enables the kernel to prove that all locking
700 that occurs in the kernel runtime is mathematically
701 correct: that under no circumstance could an arbitrary (and
702 not yet triggered) combination of observed locking
703 sequences (on an arbitrary number of CPUs, running an
704 arbitrary number of tasks and interrupt contexts) cause a
705 deadlock.
707 In short, this feature enables the kernel to report locking
708 related deadlocks before they actually occur.
710 The proof does not depend on how hard and complex a
711 deadlock scenario would be to trigger: how many
712 participant CPUs, tasks and irq-contexts would be needed
713 for it to trigger. The proof also does not depend on
714 timing: if a race and a resulting deadlock is possible
715 theoretically (no matter how unlikely the race scenario
716 is), it will be proven so and will immediately be
717 reported by the kernel (once the event is observed that
718 makes the deadlock theoretically possible).
720 If a deadlock is impossible (i.e. the locking rules, as
721 observed by the kernel, are mathematically correct), the
722 kernel reports nothing.
724 NOTE: this feature can also be enabled for rwlocks, mutexes
725 and rwsems - in which case all dependencies between these
726 different locking variants are observed and mapped too, and
727 the proof of observed correctness is also maintained for an
728 arbitrary combination of these separate locking variants.
730 For more details, see Documentation/lockdep-design.txt.
732 config LOCKDEP
733 bool
734 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
735 select STACKTRACE
736 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
737 select KALLSYMS
738 select KALLSYMS_ALL
740 config LOCK_STAT
741 bool "Lock usage statistics"
742 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
743 select LOCKDEP
744 select DEBUG_SPINLOCK
745 select DEBUG_MUTEXES
746 select DEBUG_LOCK_ALLOC
747 default n
748 help
749 This feature enables tracking lock contention points
751 For more details, see Documentation/lockstat.txt
753 This also enables lock events required by "perf lock",
754 subcommand of perf.
755 If you want to use "perf lock", you also need to turn on
756 CONFIG_EVENT_TRACING.
758 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
759 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
761 config DEBUG_LOCKDEP
762 bool "Lock dependency engine debugging"
763 depends on DEBUG_KERNEL && LOCKDEP
764 help
765 If you say Y here, the lock dependency engine will do
766 additional runtime checks to debug itself, at the price
767 of more runtime overhead.
769 config TRACE_IRQFLAGS
770 bool
771 help
772 Enables hooks to interrupt enabling and disabling for
773 either tracing or lock debugging.
775 config DEBUG_ATOMIC_SLEEP
776 bool "Sleep inside atomic section checking"
777 select PREEMPT_COUNT
778 depends on DEBUG_KERNEL
779 help
780 If you say Y here, various routines which may sleep will become very
781 noisy if they are called inside atomic sections: when a spinlock is
782 held, inside an rcu read side critical section, inside preempt disabled
783 sections, inside an interrupt, etc...
785 config DEBUG_LOCKING_API_SELFTESTS
786 bool "Locking API boot-time self-tests"
787 depends on DEBUG_KERNEL
788 help
789 Say Y here if you want the kernel to run a short self-test during
790 bootup. The self-test checks whether common types of locking bugs
791 are detected by debugging mechanisms or not. (if you disable
792 lock debugging then those bugs wont be detected of course.)
793 The following locking APIs are covered: spinlocks, rwlocks,
794 mutexes and rwsems.
796 config STACKTRACE
797 bool
798 depends on STACKTRACE_SUPPORT
800 config DEBUG_KOBJECT
801 bool "kobject debugging"
802 depends on DEBUG_KERNEL
803 help
804 If you say Y here, some extra kobject debugging messages will be sent
805 to the syslog.
807 config HAVE_DEBUG_BUGVERBOSE
808 bool
810 config DEBUG_BUGVERBOSE
811 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
812 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
813 default y
814 help
815 Say Y here to make BUG() panics output the file name and line number
816 of the BUG call as well as the EIP and oops trace. This aids
817 debugging but costs about 70-100K of memory.
819 config DEBUG_INFO
820 bool "Compile the kernel with debug info"
821 depends on DEBUG_KERNEL
822 help
823 If you say Y here the resulting kernel image will include
824 debugging info resulting in a larger kernel image.
825 This adds debug symbols to the kernel and modules (gcc -g), and
826 is needed if you intend to use kernel crashdump or binary object
827 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
828 Say Y here only if you plan to debug the kernel.
830 If unsure, say N.
832 config DEBUG_INFO_REDUCED
833 bool "Reduce debugging information"
834 depends on DEBUG_INFO
835 help
836 If you say Y here gcc is instructed to generate less debugging
837 information for structure types. This means that tools that
838 need full debugging information (like kgdb or systemtap) won't
839 be happy. But if you merely need debugging information to
840 resolve line numbers there is no loss. Advantage is that
841 build directory object sizes shrink dramatically over a full
842 DEBUG_INFO build and compile times are reduced too.
843 Only works with newer gcc versions.
845 config DEBUG_WRITECOUNT
846 bool "Debug filesystem writers count"
847 depends on DEBUG_KERNEL
848 help
849 Enable this to catch wrong use of the writers count in struct
850 vfsmount. This will increase the size of each file struct by
851 32 bits.
853 If unsure, say N.
855 config DEBUG_LIST
856 bool "Debug linked list manipulation"
857 depends on DEBUG_KERNEL
858 help
859 Enable this to turn on extended checks in the linked-list
860 walking routines.
862 If unsure, say N.
864 config DEBUG_SG
865 bool "Debug SG table operations"
866 depends on DEBUG_KERNEL
867 help
868 Enable this to turn on checks on scatter-gather tables. This can
869 help find problems with drivers that do not properly initialize
870 their sg tables.
872 If unsure, say N.
874 config DEBUG_NOTIFIERS
875 bool "Debug notifier call chains"
876 depends on DEBUG_KERNEL
877 help
878 Enable this to turn on sanity checking for notifier call chains.
879 This is most useful for kernel developers to make sure that
880 modules properly unregister themselves from notifier chains.
881 This is a relatively cheap check but if you care about maximum
882 performance, say N.
884 config DEBUG_CREDENTIALS
885 bool "Debug credential management"
886 depends on DEBUG_KERNEL
887 help
888 Enable this to turn on some debug checking for credential
889 management. The additional code keeps track of the number of
890 pointers from task_structs to any given cred struct, and checks to
891 see that this number never exceeds the usage count of the cred
892 struct.
894 Furthermore, if SELinux is enabled, this also checks that the
895 security pointer in the cred struct is never seen to be invalid.
897 If unsure, say N.
899 #
900 # Select this config option from the architecture Kconfig, if it
901 # is preferred to always offer frame pointers as a config
902 # option on the architecture (regardless of KERNEL_DEBUG):
903 #
904 config ARCH_WANT_FRAME_POINTERS
905 bool
906 help
908 config FRAME_POINTER
909 bool "Compile the kernel with frame pointers"
910 depends on DEBUG_KERNEL && \
911 (CRIS || M68K || FRV || UML || \
912 AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \
913 ARCH_WANT_FRAME_POINTERS
914 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
915 help
916 If you say Y here the resulting kernel image will be slightly
917 larger and slower, but it gives very useful debugging information
918 in case of kernel bugs. (precise oopses/stacktraces/warnings)
920 config BOOT_PRINTK_DELAY
921 bool "Delay each boot printk message by N milliseconds"
922 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
923 help
924 This build option allows you to read kernel boot messages
925 by inserting a short delay after each one. The delay is
926 specified in milliseconds on the kernel command line,
927 using "boot_delay=N".
929 It is likely that you would also need to use "lpj=M" to preset
930 the "loops per jiffie" value.
931 See a previous boot log for the "lpj" value to use for your
932 system, and then set "lpj=M" before setting "boot_delay=N".
933 NOTE: Using this option may adversely affect SMP systems.
934 I.e., processors other than the first one may not boot up.
935 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
936 what it believes to be lockup conditions.
938 menu "RCU Debugging"
940 config PROVE_RCU
941 bool "RCU debugging: prove RCU correctness"
942 depends on PROVE_LOCKING
943 default n
944 help
945 This feature enables lockdep extensions that check for correct
946 use of RCU APIs. This is currently under development. Say Y
947 if you want to debug RCU usage or help work on the PROVE_RCU
948 feature.
950 Say N if you are unsure.
952 config PROVE_RCU_REPEATEDLY
953 bool "RCU debugging: don't disable PROVE_RCU on first splat"
954 depends on PROVE_RCU
955 default n
956 help
957 By itself, PROVE_RCU will disable checking upon issuing the
958 first warning (or "splat"). This feature prevents such
959 disabling, allowing multiple RCU-lockdep warnings to be printed
960 on a single reboot.
962 Say Y to allow multiple RCU-lockdep warnings per boot.
964 Say N if you are unsure.
966 config PROVE_RCU_DELAY
967 bool "RCU debugging: preemptible RCU race provocation"
968 depends on DEBUG_KERNEL && PREEMPT_RCU
969 default n
970 help
971 There is a class of races that involve an unlikely preemption
972 of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
973 been set to INT_MIN. This feature inserts a delay at that
974 point to increase the probability of these races.
976 Say Y to increase probability of preemption of __rcu_read_unlock().
978 Say N if you are unsure.
980 config SPARSE_RCU_POINTER
981 bool "RCU debugging: sparse-based checks for pointer usage"
982 default n
983 help
984 This feature enables the __rcu sparse annotation for
985 RCU-protected pointers. This annotation will cause sparse
986 to flag any non-RCU used of annotated pointers. This can be
987 helpful when debugging RCU usage. Please note that this feature
988 is not intended to enforce code cleanliness; it is instead merely
989 a debugging aid.
991 Say Y to make sparse flag questionable use of RCU-protected pointers
993 Say N if you are unsure.
995 config RCU_TORTURE_TEST
996 tristate "torture tests for RCU"
997 depends on DEBUG_KERNEL
998 default n
999 help
1000 This option provides a kernel module that runs torture tests
1001 on the RCU infrastructure. The kernel module may be built
1002 after the fact on the running kernel to be tested, if desired.
1004 Say Y here if you want RCU torture tests to be built into
1005 the kernel.
1006 Say M if you want the RCU torture tests to build as a module.
1007 Say N if you are unsure.
1009 config RCU_TORTURE_TEST_RUNNABLE
1010 bool "torture tests for RCU runnable by default"
1011 depends on RCU_TORTURE_TEST = y
1012 default n
1013 help
1014 This option provides a way to build the RCU torture tests
1015 directly into the kernel without them starting up at boot
1016 time. You can use /proc/sys/kernel/rcutorture_runnable
1017 to manually override this setting. This /proc file is
1018 available only when the RCU torture tests have been built
1019 into the kernel.
1021 Say Y here if you want the RCU torture tests to start during
1022 boot (you probably don't).
1023 Say N here if you want the RCU torture tests to start only
1024 after being manually enabled via /proc.
1026 config RCU_CPU_STALL_TIMEOUT
1027 int "RCU CPU stall timeout in seconds"
1028 depends on RCU_STALL_COMMON
1029 range 3 300
1030 default 21
1031 help
1032 If a given RCU grace period extends more than the specified
1033 number of seconds, a CPU stall warning is printed. If the
1034 RCU grace period persists, additional CPU stall warnings are
1035 printed at more widely spaced intervals.
1037 config RCU_CPU_STALL_VERBOSE
1038 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
1039 depends on TREE_PREEMPT_RCU
1040 default y
1041 help
1042 This option causes RCU to printk detailed per-task information
1043 for any tasks that are stalling the current RCU grace period.
1045 Say N if you are unsure.
1047 Say Y if you want to enable such checks.
1049 config RCU_CPU_STALL_INFO
1050 bool "Print additional diagnostics on RCU CPU stall"
1051 depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
1052 default n
1053 help
1054 For each stalled CPU that is aware of the current RCU grace
1055 period, print out additional per-CPU diagnostic information
1056 regarding scheduling-clock ticks, idle state, and,
1057 for RCU_FAST_NO_HZ kernels, idle-entry state.
1059 Say N if you are unsure.
1061 Say Y if you want to enable such diagnostics.
1063 config RCU_TRACE
1064 bool "Enable tracing for RCU"
1065 depends on DEBUG_KERNEL
1066 select TRACE_CLOCK
1067 help
1068 This option provides tracing in RCU which presents stats
1069 in debugfs for debugging RCU implementation.
1071 Say Y here if you want to enable RCU tracing
1072 Say N if you are unsure.
1074 endmenu # "RCU Debugging"
1076 config DEBUG_BLOCK_EXT_DEVT
1077 bool "Force extended block device numbers and spread them"
1078 depends on DEBUG_KERNEL
1079 depends on BLOCK
1080 default n
1081 help
1082 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1083 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1084 YOU ARE DOING. Distros, please enable this and fix whatever
1085 is broken.
1087 Conventionally, block device numbers are allocated from
1088 predetermined contiguous area. However, extended block area
1089 may introduce non-contiguous block device numbers. This
1090 option forces most block device numbers to be allocated from
1091 the extended space and spreads them to discover kernel or
1092 userland code paths which assume predetermined contiguous
1093 device number allocation.
1095 Note that turning on this debug option shuffles all the
1096 device numbers for all IDE and SCSI devices including libata
1097 ones, so root partition specified using device number
1098 directly (via rdev or root=MAJ:MIN) won't work anymore.
1099 Textual device names (root=/dev/sdXn) will continue to work.
1101 Say N if you are unsure.
1103 config DEBUG_FORCE_WEAK_PER_CPU
1104 bool "Force weak per-cpu definitions"
1105 depends on DEBUG_KERNEL
1106 help
1107 s390 and alpha require percpu variables in modules to be
1108 defined weak to work around addressing range issue which
1109 puts the following two restrictions on percpu variable
1110 definitions.
1112 1. percpu symbols must be unique whether static or not
1113 2. percpu variables can't be defined inside a function
1115 To ensure that generic code follows the above rules, this
1116 option forces all percpu variables to be defined as weak.
1118 config NOTIFIER_ERROR_INJECTION
1119 tristate "Notifier error injection"
1120 depends on DEBUG_KERNEL
1121 select DEBUG_FS
1122 help
1123 This option provides the ability to inject artificial errors to
1124 specified notifier chain callbacks. It is useful to test the error
1125 handling of notifier call chain failures.
1127 Say N if unsure.
1129 config CPU_NOTIFIER_ERROR_INJECT
1130 tristate "CPU notifier error injection module"
1131 depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
1132 help
1133 This option provides a kernel module that can be used to test
1134 the error handling of the cpu notifiers by injecting artificial
1135 errors to CPU notifier chain callbacks. It is controlled through
1136 debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu
1138 If the notifier call chain should be failed with some events
1139 notified, write the error code to "actions/<notifier event>/error".
1141 Example: Inject CPU offline error (-1 == -EPERM)
1143 # cd /sys/kernel/debug/notifier-error-inject/cpu
1144 # echo -1 > actions/CPU_DOWN_PREPARE/error
1145 # echo 0 > /sys/devices/system/cpu/cpu1/online
1146 bash: echo: write error: Operation not permitted
1148 To compile this code as a module, choose M here: the module will
1149 be called cpu-notifier-error-inject.
1151 If unsure, say N.
1153 config PM_NOTIFIER_ERROR_INJECT
1154 tristate "PM notifier error injection module"
1155 depends on PM && NOTIFIER_ERROR_INJECTION
1156 default m if PM_DEBUG
1157 help
1158 This option provides the ability to inject artificial errors to
1159 PM notifier chain callbacks. It is controlled through debugfs
1160 interface /sys/kernel/debug/notifier-error-inject/pm
1162 If the notifier call chain should be failed with some events
1163 notified, write the error code to "actions/<notifier event>/error".
1165 Example: Inject PM suspend error (-12 = -ENOMEM)
1167 # cd /sys/kernel/debug/notifier-error-inject/pm/
1168 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1169 # echo mem > /sys/power/state
1170 bash: echo: write error: Cannot allocate memory
1172 To compile this code as a module, choose M here: the module will
1173 be called pm-notifier-error-inject.
1175 If unsure, say N.
1177 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1178 tristate "OF reconfig notifier error injection module"
1179 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1180 help
1181 This option provides the ability to inject artificial errors to
1182 OF reconfig notifier chain callbacks. It is controlled
1183 through debugfs interface under
1184 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1186 If the notifier call chain should be failed with some events
1187 notified, write the error code to "actions/<notifier event>/error".
1189 To compile this code as a module, choose M here: the module will
1190 be called of-reconfig-notifier-error-inject.
1192 If unsure, say N.
1194 config FAULT_INJECTION
1195 bool "Fault-injection framework"
1196 depends on DEBUG_KERNEL
1197 help
1198 Provide fault-injection framework.
1199 For more details, see Documentation/fault-injection/.
1201 config FAILSLAB
1202 bool "Fault-injection capability for kmalloc"
1203 depends on FAULT_INJECTION
1204 depends on SLAB || SLUB
1205 help
1206 Provide fault-injection capability for kmalloc.
1208 config FAIL_PAGE_ALLOC
1209 bool "Fault-injection capabilitiy for alloc_pages()"
1210 depends on FAULT_INJECTION
1211 help
1212 Provide fault-injection capability for alloc_pages().
1214 config FAIL_MAKE_REQUEST
1215 bool "Fault-injection capability for disk IO"
1216 depends on FAULT_INJECTION && BLOCK
1217 help
1218 Provide fault-injection capability for disk IO.
1220 config FAIL_IO_TIMEOUT
1221 bool "Fault-injection capability for faking disk interrupts"
1222 depends on FAULT_INJECTION && BLOCK
1223 help
1224 Provide fault-injection capability on end IO handling. This
1225 will make the block layer "forget" an interrupt as configured,
1226 thus exercising the error handling.
1228 Only works with drivers that use the generic timeout handling,
1229 for others it wont do anything.
1231 config FAIL_MMC_REQUEST
1232 bool "Fault-injection capability for MMC IO"
1233 select DEBUG_FS
1234 depends on FAULT_INJECTION && MMC
1235 help
1236 Provide fault-injection capability for MMC IO.
1237 This will make the mmc core return data errors. This is
1238 useful to test the error handling in the mmc block device
1239 and to test how the mmc host driver handles retries from
1240 the block device.
1242 config FAULT_INJECTION_DEBUG_FS
1243 bool "Debugfs entries for fault-injection capabilities"
1244 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1245 help
1246 Enable configuration of fault-injection capabilities via debugfs.
1248 config FAULT_INJECTION_STACKTRACE_FILTER
1249 bool "stacktrace filter for fault-injection capabilities"
1250 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1251 depends on !X86_64
1252 select STACKTRACE
1253 select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
1254 help
1255 Provide stacktrace filter for fault-injection capabilities
1257 config LATENCYTOP
1258 bool "Latency measuring infrastructure"
1259 depends on HAVE_LATENCYTOP_SUPPORT
1260 depends on DEBUG_KERNEL
1261 depends on STACKTRACE_SUPPORT
1262 depends on PROC_FS
1263 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
1264 select KALLSYMS
1265 select KALLSYMS_ALL
1266 select STACKTRACE
1267 select SCHEDSTATS
1268 select SCHED_DEBUG
1269 help
1270 Enable this option if you want to use the LatencyTOP tool
1271 to find out which userspace is blocking on what kernel operations.
1273 config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1274 bool
1276 config DEBUG_STRICT_USER_COPY_CHECKS
1277 bool "Strict user copy size checks"
1278 depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1279 depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING
1280 help
1281 Enabling this option turns a certain set of sanity checks for user
1282 copy operations into compile time failures.
1284 The copy_from_user() etc checks are there to help test if there
1285 are sufficient security checks on the length argument of
1286 the copy operation, by having gcc prove that the argument is
1287 within bounds.
1289 If unsure, say N.
1291 source kernel/trace/Kconfig
1293 menu "Runtime Testing"
1295 config LKDTM
1296 tristate "Linux Kernel Dump Test Tool Module"
1297 depends on DEBUG_FS
1298 depends on BLOCK
1299 default n
1300 help
1301 This module enables testing of the different dumping mechanisms by
1302 inducing system failures at predefined crash points.
1303 If you don't need it: say N
1304 Choose M here to compile this code as a module. The module will be
1305 called lkdtm.
1307 Documentation on how to use the module can be found in
1308 Documentation/fault-injection/provoke-crashes.txt
1310 config TEST_LIST_SORT
1311 bool "Linked list sorting test"
1312 depends on DEBUG_KERNEL
1313 help
1314 Enable this to turn on 'list_sort()' function test. This test is
1315 executed only once during system boot, so affects only boot time.
1317 If unsure, say N.
1319 config KPROBES_SANITY_TEST
1320 bool "Kprobes sanity tests"
1321 depends on DEBUG_KERNEL
1322 depends on KPROBES
1323 default n
1324 help
1325 This option provides for testing basic kprobes functionality on
1326 boot. A sample kprobe, jprobe and kretprobe are inserted and
1327 verified for functionality.
1329 Say N if you are unsure.
1331 config BACKTRACE_SELF_TEST
1332 tristate "Self test for the backtrace code"
1333 depends on DEBUG_KERNEL
1334 default n
1335 help
1336 This option provides a kernel module that can be used to test
1337 the kernel stack backtrace code. This option is not useful
1338 for distributions or general kernels, but only for kernel
1339 developers working on architecture code.
1341 Note that if you want to also test saved backtraces, you will
1342 have to enable STACKTRACE as well.
1344 Say N if you are unsure.
1346 config RBTREE_TEST
1347 tristate "Red-Black tree test"
1348 depends on m && DEBUG_KERNEL
1349 help
1350 A benchmark measuring the performance of the rbtree library.
1351 Also includes rbtree invariant checks.
1353 config INTERVAL_TREE_TEST
1354 tristate "Interval tree test"
1355 depends on m && DEBUG_KERNEL
1356 help
1357 A benchmark measuring the performance of the interval tree library
1359 config ATOMIC64_SELFTEST
1360 bool "Perform an atomic64_t self-test at boot"
1361 help
1362 Enable this option to test the atomic64_t functions at boot.
1364 If unsure, say N.
1366 config ASYNC_RAID6_TEST
1367 tristate "Self test for hardware accelerated raid6 recovery"
1368 depends on ASYNC_RAID6_RECOV
1369 select ASYNC_MEMCPY
1370 ---help---
1371 This is a one-shot self test that permutes through the
1372 recovery of all the possible two disk failure scenarios for a
1373 N-disk array. Recovery is performed with the asynchronous
1374 raid6 recovery routines, and will optionally use an offload
1375 engine if one is available.
1377 If unsure, say N.
1379 config TEST_STRING_HELPERS
1380 tristate "Test functions located in the string_helpers module at runtime"
1382 config TEST_KSTRTOX
1383 tristate "Test kstrto*() family of functions at runtime"
1385 endmenu # runtime tests
1387 config PROVIDE_OHCI1394_DMA_INIT
1388 bool "Remote debugging over FireWire early on boot"
1389 depends on PCI && X86
1390 help
1391 If you want to debug problems which hang or crash the kernel early
1392 on boot and the crashing machine has a FireWire port, you can use
1393 this feature to remotely access the memory of the crashed machine
1394 over FireWire. This employs remote DMA as part of the OHCI1394
1395 specification which is now the standard for FireWire controllers.
1397 With remote DMA, you can monitor the printk buffer remotely using
1398 firescope and access all memory below 4GB using fireproxy from gdb.
1399 Even controlling a kernel debugger is possible using remote DMA.
1401 Usage:
1403 If ohci1394_dma=early is used as boot parameter, it will initialize
1404 all OHCI1394 controllers which are found in the PCI config space.
1406 As all changes to the FireWire bus such as enabling and disabling
1407 devices cause a bus reset and thereby disable remote DMA for all
1408 devices, be sure to have the cable plugged and FireWire enabled on
1409 the debugging host before booting the debug target for debugging.
1411 This code (~1k) is freed after boot. By then, the firewire stack
1412 in charge of the OHCI-1394 controllers should be used instead.
1414 See Documentation/debugging-via-ohci1394.txt for more information.
1416 config FIREWIRE_OHCI_REMOTE_DMA
1417 bool "Remote debugging over FireWire with firewire-ohci"
1418 depends on FIREWIRE_OHCI
1419 help
1420 This option lets you use the FireWire bus for remote debugging
1421 with help of the firewire-ohci driver. It enables unfiltered
1422 remote DMA in firewire-ohci.
1423 See Documentation/debugging-via-ohci1394.txt for more information.
1425 If unsure, say N.
1427 config BUILD_DOCSRC
1428 bool "Build targets in Documentation/ tree"
1429 depends on HEADERS_CHECK
1430 help
1431 This option attempts to build objects from the source files in the
1432 kernel Documentation/ tree.
1434 Say N if you are unsure.
1436 config DYNAMIC_DEBUG
1437 bool "Enable dynamic printk() support"
1438 default n
1439 depends on PRINTK
1440 depends on DEBUG_FS
1441 help
1443 Compiles debug level messages into the kernel, which would not
1444 otherwise be available at runtime. These messages can then be
1445 enabled/disabled based on various levels of scope - per source file,
1446 function, module, format string, and line number. This mechanism
1447 implicitly compiles in all pr_debug() and dev_dbg() calls, which
1448 enlarges the kernel text size by about 2%.
1450 If a source file is compiled with DEBUG flag set, any
1451 pr_debug() calls in it are enabled by default, but can be
1452 disabled at runtime as below. Note that DEBUG flag is
1453 turned on by many CONFIG_*DEBUG* options.
1455 Usage:
1457 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
1458 which is contained in the 'debugfs' filesystem. Thus, the debugfs
1459 filesystem must first be mounted before making use of this feature.
1460 We refer the control file as: <debugfs>/dynamic_debug/control. This
1461 file contains a list of the debug statements that can be enabled. The
1462 format for each line of the file is:
1464 filename:lineno [module]function flags format
1466 filename : source file of the debug statement
1467 lineno : line number of the debug statement
1468 module : module that contains the debug statement
1469 function : function that contains the debug statement
1470 flags : '=p' means the line is turned 'on' for printing
1471 format : the format used for the debug statement
1473 From a live system:
1475 nullarbor:~ # cat <debugfs>/dynamic_debug/control
1476 # filename:lineno [module]function flags format
1477 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
1478 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
1479 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
1481 Example usage:
1483 // enable the message at line 1603 of file svcsock.c
1484 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
1485 <debugfs>/dynamic_debug/control
1487 // enable all the messages in file svcsock.c
1488 nullarbor:~ # echo -n 'file svcsock.c +p' >
1489 <debugfs>/dynamic_debug/control
1491 // enable all the messages in the NFS server module
1492 nullarbor:~ # echo -n 'module nfsd +p' >
1493 <debugfs>/dynamic_debug/control
1495 // enable all 12 messages in the function svc_process()
1496 nullarbor:~ # echo -n 'func svc_process +p' >
1497 <debugfs>/dynamic_debug/control
1499 // disable all 12 messages in the function svc_process()
1500 nullarbor:~ # echo -n 'func svc_process -p' >
1501 <debugfs>/dynamic_debug/control
1503 See Documentation/dynamic-debug-howto.txt for additional information.
1505 config DMA_API_DEBUG
1506 bool "Enable debugging of DMA-API usage"
1507 depends on HAVE_DMA_API_DEBUG
1508 help
1509 Enable this option to debug the use of the DMA API by device drivers.
1510 With this option you will be able to detect common bugs in device
1511 drivers like double-freeing of DMA mappings or freeing mappings that
1512 were never allocated.
1513 This option causes a performance degredation. Use only if you want
1514 to debug device drivers. If unsure, say N.
1516 source "samples/Kconfig"
1518 source "lib/Kconfig.kgdb"