| blob | 1b4afd2e6ca089de0babdacc5781426ef118da5c |
2 config PRINTK_TIME
3 bool "Show timing information on printks"
4 depends on PRINTK
5 help
6 Selecting this option causes timing information to be
7 included in printk output. This allows you to measure
8 the interval between kernel operations, including bootup
9 operations. This is useful for identifying long delays
10 in kernel startup.
12 config ENABLE_WARN_DEPRECATED
13 bool "Enable __deprecated logic"
14 default y
15 help
16 Enable the __deprecated logic in the kernel build.
17 Disable this to suppress the "warning: 'foo' is deprecated
18 (declared at kernel/power/somefile.c:1234)" messages.
20 config ENABLE_MUST_CHECK
21 bool "Enable __must_check logic"
22 default y
23 help
24 Enable the __must_check logic in the kernel build. Disable this to
25 suppress the "warning: ignoring return value of 'foo', declared with
26 attribute warn_unused_result" messages.
28 config FRAME_WARN
29 int "Warn for stack frames larger than (needs gcc 4.4)"
30 range 0 8192
31 default 1024 if !64BIT
32 default 2048 if 64BIT
33 help
34 Tell gcc to warn at build time for stack frames larger than this.
35 Setting this too low will cause a lot of warnings.
36 Setting it to 0 disables the warning.
37 Requires gcc 4.4
39 config MAGIC_SYSRQ
40 bool "Magic SysRq key"
41 depends on !UML
42 help
43 If you say Y here, you will have some control over the system even
44 if the system crashes for example during kernel debugging (e.g., you
45 will be able to flush the buffer cache to disk, reboot the system
46 immediately or dump some status information). This is accomplished
47 by pressing various keys while holding SysRq (Alt+PrintScreen). It
48 also works on a serial console (on PC hardware at least), if you
49 send a BREAK and then within 5 seconds a command keypress. The
50 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
51 unless you really know what this hack does.
53 config STRIP_ASM_SYMS
54 bool "Strip assembler-generated symbols during link"
55 default n
56 help
57 Strip internal assembler-generated symbols during a link (symbols
58 that look like '.Lxxx') so they don't pollute the output of
59 get_wchan() and suchlike.
61 config UNUSED_SYMBOLS
62 bool "Enable unused/obsolete exported symbols"
63 default y if X86
64 help
65 Unused but exported symbols make the kernel needlessly bigger. For
66 that reason most of these unused exports will soon be removed. This
67 option is provided temporarily to provide a transition period in case
68 some external kernel module needs one of these symbols anyway. If you
69 encounter such a case in your module, consider if you are actually
70 using the right API. (rationale: since nobody in the kernel is using
71 this in a module, there is a pretty good chance it's actually the
72 wrong interface to use). If you really need the symbol, please send a
73 mail to the linux kernel mailing list mentioning the symbol and why
74 you really need it, and what the merge plan to the mainline kernel for
75 your module is.
77 config DEBUG_FS
78 bool "Debug Filesystem"
79 help
80 debugfs is a virtual file system that kernel developers use to put
81 debugging files into. Enable this option to be able to read and
82 write to these files.
84 For detailed documentation on the debugfs API, see
85 Documentation/DocBook/filesystems.
87 If unsure, say N.
89 config HEADERS_CHECK
90 bool "Run 'make headers_check' when building vmlinux"
91 depends on !UML
92 help
93 This option will extract the user-visible kernel headers whenever
94 building the kernel, and will run basic sanity checks on them to
95 ensure that exported files do not attempt to include files which
96 were not exported, etc.
98 If you're making modifications to header files which are
99 relevant for userspace, say 'Y', and check the headers
100 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
101 your build tree), to make sure they're suitable.
103 config DEBUG_SECTION_MISMATCH
104 bool "Enable full Section mismatch analysis"
105 depends on UNDEFINED || (BLACKFIN)
106 default y
107 # This option is on purpose disabled for now.
108 # It will be enabled when we are down to a reasonable number
109 # of section mismatch warnings (< 10 for an allyesconfig build)
110 help
111 The section mismatch analysis checks if there are illegal
112 references from one section to another section.
113 Linux will during link or during runtime drop some sections
114 and any use of code/data previously in these sections will
115 most likely result in an oops.
116 In the code functions and variables are annotated with
117 __init, __devinit etc. (see full list in include/linux/init.h)
118 which results in the code/data being placed in specific sections.
119 The section mismatch analysis is always done after a full
120 kernel build but enabling this option will in addition
121 do the following:
122 - Add the option -fno-inline-functions-called-once to gcc
123 When inlining a function annotated __init in a non-init
124 function we would lose the section information and thus
125 the analysis would not catch the illegal reference.
126 This option tells gcc to inline less but will also
127 result in a larger kernel.
128 - Run the section mismatch analysis for each module/built-in.o
129 When we run the section mismatch analysis on vmlinux.o we
130 lose valueble information about where the mismatch was
131 introduced.
132 Running the analysis for each module/built-in.o file
133 will tell where the mismatch happens much closer to the
134 source. The drawback is that we will report the same
135 mismatch at least twice.
136 - Enable verbose reporting from modpost to help solving
137 the section mismatches reported.
139 config DEBUG_KERNEL
140 bool "Kernel debugging"
141 help
142 Say Y here if you are developing drivers or trying to debug and
143 identify kernel problems.
145 config DEBUG_SHIRQ
146 bool "Debug shared IRQ handlers"
147 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
148 help
149 Enable this to generate a spurious interrupt as soon as a shared
150 interrupt handler is registered, and just before one is deregistered.
151 Drivers ought to be able to handle interrupts coming in at those
152 points; some don't and need to be caught.
154 config LOCKUP_DETECTOR
155 bool "Detect Hard and Soft Lockups"
156 depends on DEBUG_KERNEL && !S390
157 help
158 Say Y here to enable the kernel to act as a watchdog to detect
159 hard and soft lockups.
161 Softlockups are bugs that cause the kernel to loop in kernel
162 mode for more than 60 seconds, without giving other tasks a
163 chance to run. The current stack trace is displayed upon
164 detection and the system will stay locked up.
166 Hardlockups are bugs that cause the CPU to loop in kernel mode
167 for more than 60 seconds, without letting other interrupts have a
168 chance to run. The current stack trace is displayed upon detection
169 and the system will stay locked up.
171 The overhead should be minimal. A periodic hrtimer runs to
172 generate interrupts and kick the watchdog task every 10-12 seconds.
173 An NMI is generated every 60 seconds or so to check for hardlockups.
175 config HARDLOCKUP_DETECTOR
176 def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI
178 config BOOTPARAM_SOFTLOCKUP_PANIC
179 bool "Panic (Reboot) On Soft Lockups"
180 depends on LOCKUP_DETECTOR
181 help
182 Say Y here to enable the kernel to panic on "soft lockups",
183 which are bugs that cause the kernel to loop in kernel
184 mode for more than 60 seconds, without giving other tasks a
185 chance to run.
187 The panic can be used in combination with panic_timeout,
188 to cause the system to reboot automatically after a
189 lockup has been detected. This feature is useful for
190 high-availability systems that have uptime guarantees and
191 where a lockup must be resolved ASAP.
193 Say N if unsure.
195 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
196 int
197 depends on LOCKUP_DETECTOR
198 range 0 1
199 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
200 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
202 config DETECT_HUNG_TASK
203 bool "Detect Hung Tasks"
204 depends on DEBUG_KERNEL
205 default DETECT_SOFTLOCKUP
206 help
207 Say Y here to enable the kernel to detect "hung tasks",
208 which are bugs that cause the task to be stuck in
209 uninterruptible "D" state indefinitiley.
211 When a hung task is detected, the kernel will print the
212 current stack trace (which you should report), but the
213 task will stay in uninterruptible state. If lockdep is
214 enabled then all held locks will also be reported. This
215 feature has negligible overhead.
217 config BOOTPARAM_HUNG_TASK_PANIC
218 bool "Panic (Reboot) On Hung Tasks"
219 depends on DETECT_HUNG_TASK
220 help
221 Say Y here to enable the kernel to panic on "hung tasks",
222 which are bugs that cause the kernel to leave a task stuck
223 in uninterruptible "D" state.
225 The panic can be used in combination with panic_timeout,
226 to cause the system to reboot automatically after a
227 hung task has been detected. This feature is useful for
228 high-availability systems that have uptime guarantees and
229 where a hung tasks must be resolved ASAP.
231 Say N if unsure.
233 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
234 int
235 depends on DETECT_HUNG_TASK
236 range 0 1
237 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
238 default 1 if BOOTPARAM_HUNG_TASK_PANIC
240 config SCHED_DEBUG
241 bool "Collect scheduler debugging info"
242 depends on DEBUG_KERNEL && PROC_FS
243 default y
244 help
245 If you say Y here, the /proc/sched_debug file will be provided
246 that can help debug the scheduler. The runtime overhead of this
247 option is minimal.
249 config SCHEDSTATS
250 bool "Collect scheduler statistics"
251 depends on DEBUG_KERNEL && PROC_FS
252 help
253 If you say Y here, additional code will be inserted into the
254 scheduler and related routines to collect statistics about
255 scheduler behavior and provide them in /proc/schedstat. These
256 stats may be useful for both tuning and debugging the scheduler
257 If you aren't debugging the scheduler or trying to tune a specific
258 application, you can say N to avoid the very slight overhead
259 this adds.
261 config TIMER_STATS
262 bool "Collect kernel timers statistics"
263 depends on DEBUG_KERNEL && PROC_FS
264 help
265 If you say Y here, additional code will be inserted into the
266 timer routines to collect statistics about kernel timers being
267 reprogrammed. The statistics can be read from /proc/timer_stats.
268 The statistics collection is started by writing 1 to /proc/timer_stats,
269 writing 0 stops it. This feature is useful to collect information
270 about timer usage patterns in kernel and userspace. This feature
271 is lightweight if enabled in the kernel config but not activated
272 (it defaults to deactivated on bootup and will only be activated
273 if some application like powertop activates it explicitly).
275 config DEBUG_OBJECTS
276 bool "Debug object operations"
277 depends on DEBUG_KERNEL
278 help
279 If you say Y here, additional code will be inserted into the
280 kernel to track the life time of various objects and validate
281 the operations on those objects.
283 config DEBUG_OBJECTS_SELFTEST
284 bool "Debug objects selftest"
285 depends on DEBUG_OBJECTS
286 help
287 This enables the selftest of the object debug code.
289 config DEBUG_OBJECTS_FREE
290 bool "Debug objects in freed memory"
291 depends on DEBUG_OBJECTS
292 help
293 This enables checks whether a k/v free operation frees an area
294 which contains an object which has not been deactivated
295 properly. This can make kmalloc/kfree-intensive workloads
296 much slower.
298 config DEBUG_OBJECTS_TIMERS
299 bool "Debug timer objects"
300 depends on DEBUG_OBJECTS
301 help
302 If you say Y here, additional code will be inserted into the
303 timer routines to track the life time of timer objects and
304 validate the timer operations.
306 config DEBUG_OBJECTS_WORK
307 bool "Debug work objects"
308 depends on DEBUG_OBJECTS
309 help
310 If you say Y here, additional code will be inserted into the
311 work queue routines to track the life time of work objects and
312 validate the work operations.
314 config DEBUG_OBJECTS_RCU_HEAD
315 bool "Debug RCU callbacks objects"
316 depends on DEBUG_OBJECTS && PREEMPT
317 help
318 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
320 config DEBUG_OBJECTS_ENABLE_DEFAULT
321 int "debug_objects bootup default value (0-1)"
322 range 0 1
323 default "1"
324 depends on DEBUG_OBJECTS
325 help
326 Debug objects boot parameter default value
328 config DEBUG_SLAB
329 bool "Debug slab memory allocations"
330 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
331 help
332 Say Y here to have the kernel do limited verification on memory
333 allocation as well as poisoning memory on free to catch use of freed
334 memory. This can make kmalloc/kfree-intensive workloads much slower.
336 config DEBUG_SLAB_LEAK
337 bool "Memory leak debugging"
338 depends on DEBUG_SLAB
340 config SLUB_DEBUG_ON
341 bool "SLUB debugging on by default"
342 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
343 default n
344 help
345 Boot with debugging on by default. SLUB boots by default with
346 the runtime debug capabilities switched off. Enabling this is
347 equivalent to specifying the "slub_debug" parameter on boot.
348 There is no support for more fine grained debug control like
349 possible with slub_debug=xxx. SLUB debugging may be switched
350 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
351 "slub_debug=-".
353 config SLUB_STATS
354 default n
355 bool "Enable SLUB performance statistics"
356 depends on SLUB && SLUB_DEBUG && SYSFS
357 help
358 SLUB statistics are useful to debug SLUBs allocation behavior in
359 order find ways to optimize the allocator. This should never be
360 enabled for production use since keeping statistics slows down
361 the allocator by a few percentage points. The slabinfo command
362 supports the determination of the most active slabs to figure
363 out which slabs are relevant to a particular load.
364 Try running: slabinfo -DA
366 config DEBUG_KMEMLEAK
367 bool "Kernel memory leak detector"
368 depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
369 (X86 || ARM || PPC || S390 || SPARC64 || SUPERH || MICROBLAZE)
371 select DEBUG_FS if SYSFS
372 select STACKTRACE if STACKTRACE_SUPPORT
373 select KALLSYMS
374 select CRC32
375 help
376 Say Y here if you want to enable the memory leak
377 detector. The memory allocation/freeing is traced in a way
378 similar to the Boehm's conservative garbage collector, the
379 difference being that the orphan objects are not freed but
380 only shown in /sys/kernel/debug/kmemleak. Enabling this
381 feature will introduce an overhead to memory
382 allocations. See Documentation/kmemleak.txt for more
383 details.
385 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
386 of finding leaks due to the slab objects poisoning.
388 In order to access the kmemleak file, debugfs needs to be
389 mounted (usually at /sys/kernel/debug).
391 config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
392 int "Maximum kmemleak early log entries"
393 depends on DEBUG_KMEMLEAK
394 range 200 40000
395 default 400
396 help
397 Kmemleak must track all the memory allocations to avoid
398 reporting false positives. Since memory may be allocated or
399 freed before kmemleak is initialised, an early log buffer is
400 used to store these actions. If kmemleak reports "early log
401 buffer exceeded", please increase this value.
403 config DEBUG_KMEMLEAK_TEST
404 tristate "Simple test for the kernel memory leak detector"
405 depends on DEBUG_KMEMLEAK
406 help
407 Say Y or M here to build a test for the kernel memory leak
408 detector. This option enables a module that explicitly leaks
409 memory.
411 If unsure, say N.
413 config DEBUG_KMEMLEAK_DEFAULT_OFF
414 bool "Default kmemleak to off"
415 depends on DEBUG_KMEMLEAK
416 help
417 Say Y here to disable kmemleak by default. It can then be enabled
418 on the command line via kmemleak=on.
420 config DEBUG_PREEMPT
421 bool "Debug preemptible kernel"
422 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
423 default y
424 help
425 If you say Y here then the kernel will use a debug variant of the
426 commonly used smp_processor_id() function and will print warnings
427 if kernel code uses it in a preemption-unsafe way. Also, the kernel
428 will detect preemption count underflows.
430 config DEBUG_RT_MUTEXES
431 bool "RT Mutex debugging, deadlock detection"
432 depends on DEBUG_KERNEL && RT_MUTEXES
433 help
434 This allows rt mutex semantics violations and rt mutex related
435 deadlocks (lockups) to be detected and reported automatically.
437 config DEBUG_PI_LIST
438 bool
439 default y
440 depends on DEBUG_RT_MUTEXES
442 config RT_MUTEX_TESTER
443 bool "Built-in scriptable tester for rt-mutexes"
444 depends on DEBUG_KERNEL && RT_MUTEXES
445 help
446 This option enables a rt-mutex tester.
448 config DEBUG_SPINLOCK
449 bool "Spinlock and rw-lock debugging: basic checks"
450 depends on DEBUG_KERNEL
451 help
452 Say Y here and build SMP to catch missing spinlock initialization
453 and certain other kinds of spinlock errors commonly made. This is
454 best used in conjunction with the NMI watchdog so that spinlock
455 deadlocks are also debuggable.
457 config DEBUG_MUTEXES
458 bool "Mutex debugging: basic checks"
459 depends on DEBUG_KERNEL
460 help
461 This feature allows mutex semantics violations to be detected and
462 reported.
464 config DEBUG_LOCK_ALLOC
465 bool "Lock debugging: detect incorrect freeing of live locks"
466 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
467 select DEBUG_SPINLOCK
468 select DEBUG_MUTEXES
469 select LOCKDEP
470 help
471 This feature will check whether any held lock (spinlock, rwlock,
472 mutex or rwsem) is incorrectly freed by the kernel, via any of the
473 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
474 vfree(), etc.), whether a live lock is incorrectly reinitialized via
475 spin_lock_init()/mutex_init()/etc., or whether there is any lock
476 held during task exit.
478 config PROVE_LOCKING
479 bool "Lock debugging: prove locking correctness"
480 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
481 select LOCKDEP
482 select DEBUG_SPINLOCK
483 select DEBUG_MUTEXES
484 select DEBUG_LOCK_ALLOC
485 default n
486 help
487 This feature enables the kernel to prove that all locking
488 that occurs in the kernel runtime is mathematically
489 correct: that under no circumstance could an arbitrary (and
490 not yet triggered) combination of observed locking
491 sequences (on an arbitrary number of CPUs, running an
492 arbitrary number of tasks and interrupt contexts) cause a
493 deadlock.
495 In short, this feature enables the kernel to report locking
496 related deadlocks before they actually occur.
498 The proof does not depend on how hard and complex a
499 deadlock scenario would be to trigger: how many
500 participant CPUs, tasks and irq-contexts would be needed
501 for it to trigger. The proof also does not depend on
502 timing: if a race and a resulting deadlock is possible
503 theoretically (no matter how unlikely the race scenario
504 is), it will be proven so and will immediately be
505 reported by the kernel (once the event is observed that
506 makes the deadlock theoretically possible).
508 If a deadlock is impossible (i.e. the locking rules, as
509 observed by the kernel, are mathematically correct), the
510 kernel reports nothing.
512 NOTE: this feature can also be enabled for rwlocks, mutexes
513 and rwsems - in which case all dependencies between these
514 different locking variants are observed and mapped too, and
515 the proof of observed correctness is also maintained for an
516 arbitrary combination of these separate locking variants.
518 For more details, see Documentation/lockdep-design.txt.
520 config PROVE_RCU
521 bool "RCU debugging: prove RCU correctness"
522 depends on PROVE_LOCKING
523 default n
524 help
525 This feature enables lockdep extensions that check for correct
526 use of RCU APIs. This is currently under development. Say Y
527 if you want to debug RCU usage or help work on the PROVE_RCU
528 feature.
530 Say N if you are unsure.
532 config PROVE_RCU_REPEATEDLY
533 bool "RCU debugging: don't disable PROVE_RCU on first splat"
534 depends on PROVE_RCU
535 default n
536 help
537 By itself, PROVE_RCU will disable checking upon issuing the
538 first warning (or "splat"). This feature prevents such
539 disabling, allowing multiple RCU-lockdep warnings to be printed
540 on a single reboot.
542 Say N if you are unsure.
544 config LOCKDEP
545 bool
546 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
547 select STACKTRACE
548 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
549 select KALLSYMS
550 select KALLSYMS_ALL
552 config LOCK_STAT
553 bool "Lock usage statistics"
554 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
555 select LOCKDEP
556 select DEBUG_SPINLOCK
557 select DEBUG_MUTEXES
558 select DEBUG_LOCK_ALLOC
559 default n
560 help
561 This feature enables tracking lock contention points
563 For more details, see Documentation/lockstat.txt
565 This also enables lock events required by "perf lock",
566 subcommand of perf.
567 If you want to use "perf lock", you also need to turn on
568 CONFIG_EVENT_TRACING.
570 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
571 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
573 config DEBUG_LOCKDEP
574 bool "Lock dependency engine debugging"
575 depends on DEBUG_KERNEL && LOCKDEP
576 help
577 If you say Y here, the lock dependency engine will do
578 additional runtime checks to debug itself, at the price
579 of more runtime overhead.
581 config TRACE_IRQFLAGS
582 depends on DEBUG_KERNEL
583 bool
584 default y
585 depends on TRACE_IRQFLAGS_SUPPORT
586 depends on PROVE_LOCKING
588 config DEBUG_SPINLOCK_SLEEP
589 bool "Spinlock debugging: sleep-inside-spinlock checking"
590 depends on DEBUG_KERNEL
591 help
592 If you say Y here, various routines which may sleep will become very
593 noisy if they are called with a spinlock held.
595 config DEBUG_LOCKING_API_SELFTESTS
596 bool "Locking API boot-time self-tests"
597 depends on DEBUG_KERNEL
598 help
599 Say Y here if you want the kernel to run a short self-test during
600 bootup. The self-test checks whether common types of locking bugs
601 are detected by debugging mechanisms or not. (if you disable
602 lock debugging then those bugs wont be detected of course.)
603 The following locking APIs are covered: spinlocks, rwlocks,
604 mutexes and rwsems.
606 config STACKTRACE
607 bool
608 depends on STACKTRACE_SUPPORT
610 config DEBUG_KOBJECT
611 bool "kobject debugging"
612 depends on DEBUG_KERNEL
613 help
614 If you say Y here, some extra kobject debugging messages will be sent
615 to the syslog.
617 config DEBUG_HIGHMEM
618 bool "Highmem debugging"
619 depends on DEBUG_KERNEL && HIGHMEM
620 help
621 This options enables addition error checking for high memory systems.
622 Disable for production systems.
624 config DEBUG_BUGVERBOSE
625 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
626 depends on BUG
627 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
628 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
629 default y
630 help
631 Say Y here to make BUG() panics output the file name and line number
632 of the BUG call as well as the EIP and oops trace. This aids
633 debugging but costs about 70-100K of memory.
635 config DEBUG_INFO
636 bool "Compile the kernel with debug info"
637 depends on DEBUG_KERNEL
638 help
639 If you say Y here the resulting kernel image will include
640 debugging info resulting in a larger kernel image.
641 This adds debug symbols to the kernel and modules (gcc -g), and
642 is needed if you intend to use kernel crashdump or binary object
643 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
644 Say Y here only if you plan to debug the kernel.
646 If unsure, say N.
648 config DEBUG_INFO_REDUCED
649 bool "Reduce debugging information"
650 depends on DEBUG_INFO
651 help
652 If you say Y here gcc is instructed to generate less debugging
653 information for structure types. This means that tools that
654 need full debugging information (like kgdb or systemtap) won't
655 be happy. But if you merely need debugging information to
656 resolve line numbers there is no loss. Advantage is that
657 build directory object sizes shrink dramatically over a full
658 DEBUG_INFO build and compile times are reduced too.
659 Only works with newer gcc versions.
661 config DEBUG_VM
662 bool "Debug VM"
663 depends on DEBUG_KERNEL
664 help
665 Enable this to turn on extended checks in the virtual-memory system
666 that may impact performance.
668 If unsure, say N.
670 config DEBUG_VIRTUAL
671 bool "Debug VM translations"
672 depends on DEBUG_KERNEL && X86
673 help
674 Enable some costly sanity checks in virtual to page code. This can
675 catch mistakes with virt_to_page() and friends.
677 If unsure, say N.
679 config DEBUG_NOMMU_REGIONS
680 bool "Debug the global anon/private NOMMU mapping region tree"
681 depends on DEBUG_KERNEL && !MMU
682 help
683 This option causes the global tree of anonymous and private mapping
684 regions to be regularly checked for invalid topology.
686 config DEBUG_WRITECOUNT
687 bool "Debug filesystem writers count"
688 depends on DEBUG_KERNEL
689 help
690 Enable this to catch wrong use of the writers count in struct
691 vfsmount. This will increase the size of each file struct by
692 32 bits.
694 If unsure, say N.
696 config DEBUG_MEMORY_INIT
697 bool "Debug memory initialisation" if EMBEDDED
698 default !EMBEDDED
699 help
700 Enable this for additional checks during memory initialisation.
701 The sanity checks verify aspects of the VM such as the memory model
702 and other information provided by the architecture. Verbose
703 information will be printed at KERN_DEBUG loglevel depending
704 on the mminit_loglevel= command-line option.
706 If unsure, say Y
708 config DEBUG_LIST
709 bool "Debug linked list manipulation"
710 depends on DEBUG_KERNEL
711 help
712 Enable this to turn on extended checks in the linked-list
713 walking routines.
715 If unsure, say N.
717 config DEBUG_SG
718 bool "Debug SG table operations"
719 depends on DEBUG_KERNEL
720 help
721 Enable this to turn on checks on scatter-gather tables. This can
722 help find problems with drivers that do not properly initialize
723 their sg tables.
725 If unsure, say N.
727 config DEBUG_NOTIFIERS
728 bool "Debug notifier call chains"
729 depends on DEBUG_KERNEL
730 help
731 Enable this to turn on sanity checking for notifier call chains.
732 This is most useful for kernel developers to make sure that
733 modules properly unregister themselves from notifier chains.
734 This is a relatively cheap check but if you care about maximum
735 performance, say N.
737 config DEBUG_CREDENTIALS
738 bool "Debug credential management"
739 depends on DEBUG_KERNEL
740 help
741 Enable this to turn on some debug checking for credential
742 management. The additional code keeps track of the number of
743 pointers from task_structs to any given cred struct, and checks to
744 see that this number never exceeds the usage count of the cred
745 struct.
747 Furthermore, if SELinux is enabled, this also checks that the
748 security pointer in the cred struct is never seen to be invalid.
750 If unsure, say N.
752 #
753 # Select this config option from the architecture Kconfig, if it
754 # it is preferred to always offer frame pointers as a config
755 # option on the architecture (regardless of KERNEL_DEBUG):
756 #
757 config ARCH_WANT_FRAME_POINTERS
758 bool
759 help
761 config FRAME_POINTER
762 bool "Compile the kernel with frame pointers"
763 depends on DEBUG_KERNEL && \
764 (CRIS || M68K || M68KNOMMU || FRV || UML || \
765 AVR32 || SUPERH || BLACKFIN || MN10300) || \
766 ARCH_WANT_FRAME_POINTERS
767 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
768 help
769 If you say Y here the resulting kernel image will be slightly
770 larger and slower, but it gives very useful debugging information
771 in case of kernel bugs. (precise oopses/stacktraces/warnings)
773 config BOOT_PRINTK_DELAY
774 bool "Delay each boot printk message by N milliseconds"
775 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
776 help
777 This build option allows you to read kernel boot messages
778 by inserting a short delay after each one. The delay is
779 specified in milliseconds on the kernel command line,
780 using "boot_delay=N".
782 It is likely that you would also need to use "lpj=M" to preset
783 the "loops per jiffie" value.
784 See a previous boot log for the "lpj" value to use for your
785 system, and then set "lpj=M" before setting "boot_delay=N".
786 NOTE: Using this option may adversely affect SMP systems.
787 I.e., processors other than the first one may not boot up.
788 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
789 what it believes to be lockup conditions.
791 config RCU_TORTURE_TEST
792 tristate "torture tests for RCU"
793 depends on DEBUG_KERNEL
794 default n
795 help
796 This option provides a kernel module that runs torture tests
797 on the RCU infrastructure. The kernel module may be built
798 after the fact on the running kernel to be tested, if desired.
800 Say Y here if you want RCU torture tests to be built into
801 the kernel.
802 Say M if you want the RCU torture tests to build as a module.
803 Say N if you are unsure.
805 config RCU_TORTURE_TEST_RUNNABLE
806 bool "torture tests for RCU runnable by default"
807 depends on RCU_TORTURE_TEST = y
808 default n
809 help
810 This option provides a way to build the RCU torture tests
811 directly into the kernel without them starting up at boot
812 time. You can use /proc/sys/kernel/rcutorture_runnable
813 to manually override this setting. This /proc file is
814 available only when the RCU torture tests have been built
815 into the kernel.
817 Say Y here if you want the RCU torture tests to start during
818 boot (you probably don't).
819 Say N here if you want the RCU torture tests to start only
820 after being manually enabled via /proc.
822 config RCU_CPU_STALL_DETECTOR
823 bool "Check for stalled CPUs delaying RCU grace periods"
824 depends on TREE_RCU || TREE_PREEMPT_RCU
825 default y
826 help
827 This option causes RCU to printk information on which
828 CPUs are delaying the current grace period, but only when
829 the grace period extends for excessive time periods.
831 Say N if you want to disable such checks.
833 Say Y if you are unsure.
835 config RCU_CPU_STALL_VERBOSE
836 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
837 depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU
838 default y
839 help
840 This option causes RCU to printk detailed per-task information
841 for any tasks that are stalling the current RCU grace period.
843 Say N if you are unsure.
845 Say Y if you want to enable such checks.
847 config KPROBES_SANITY_TEST
848 bool "Kprobes sanity tests"
849 depends on DEBUG_KERNEL
850 depends on KPROBES
851 default n
852 help
853 This option provides for testing basic kprobes functionality on
854 boot. A sample kprobe, jprobe and kretprobe are inserted and
855 verified for functionality.
857 Say N if you are unsure.
859 config BACKTRACE_SELF_TEST
860 tristate "Self test for the backtrace code"
861 depends on DEBUG_KERNEL
862 default n
863 help
864 This option provides a kernel module that can be used to test
865 the kernel stack backtrace code. This option is not useful
866 for distributions or general kernels, but only for kernel
867 developers working on architecture code.
869 Note that if you want to also test saved backtraces, you will
870 have to enable STACKTRACE as well.
872 Say N if you are unsure.
874 config DEBUG_BLOCK_EXT_DEVT
875 bool "Force extended block device numbers and spread them"
876 depends on DEBUG_KERNEL
877 depends on BLOCK
878 default n
879 help
880 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
881 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
882 YOU ARE DOING. Distros, please enable this and fix whatever
883 is broken.
885 Conventionally, block device numbers are allocated from
886 predetermined contiguous area. However, extended block area
887 may introduce non-contiguous block device numbers. This
888 option forces most block device numbers to be allocated from
889 the extended space and spreads them to discover kernel or
890 userland code paths which assume predetermined contiguous
891 device number allocation.
893 Note that turning on this debug option shuffles all the
894 device numbers for all IDE and SCSI devices including libata
895 ones, so root partition specified using device number
896 directly (via rdev or root=MAJ:MIN) won't work anymore.
897 Textual device names (root=/dev/sdXn) will continue to work.
899 Say N if you are unsure.
901 config DEBUG_FORCE_WEAK_PER_CPU
902 bool "Force weak per-cpu definitions"
903 depends on DEBUG_KERNEL
904 help
905 s390 and alpha require percpu variables in modules to be
906 defined weak to work around addressing range issue which
907 puts the following two restrictions on percpu variable
908 definitions.
910 1. percpu symbols must be unique whether static or not
911 2. percpu variables can't be defined inside a function
913 To ensure that generic code follows the above rules, this
914 option forces all percpu variables to be defined as weak.
916 config LKDTM
917 tristate "Linux Kernel Dump Test Tool Module"
918 depends on DEBUG_FS
919 depends on BLOCK
920 default n
921 help
922 This module enables testing of the different dumping mechanisms by
923 inducing system failures at predefined crash points.
924 If you don't need it: say N
925 Choose M here to compile this code as a module. The module will be
926 called lkdtm.
928 Documentation on how to use the module can be found in
929 Documentation/fault-injection/provoke-crashes.txt
931 config CPU_NOTIFIER_ERROR_INJECT
932 tristate "CPU notifier error injection module"
933 depends on HOTPLUG_CPU && DEBUG_KERNEL
934 help
935 This option provides a kernel module that can be used to test
936 the error handling of the cpu notifiers
938 To compile this code as a module, choose M here: the module will
939 be called cpu-notifier-error-inject.
941 If unsure, say N.
943 config FAULT_INJECTION
944 bool "Fault-injection framework"
945 depends on DEBUG_KERNEL
946 help
947 Provide fault-injection framework.
948 For more details, see Documentation/fault-injection/.
950 config FAILSLAB
951 bool "Fault-injection capability for kmalloc"
952 depends on FAULT_INJECTION
953 depends on SLAB || SLUB
954 help
955 Provide fault-injection capability for kmalloc.
957 config FAIL_PAGE_ALLOC
958 bool "Fault-injection capabilitiy for alloc_pages()"
959 depends on FAULT_INJECTION
960 help
961 Provide fault-injection capability for alloc_pages().
963 config FAIL_MAKE_REQUEST
964 bool "Fault-injection capability for disk IO"
965 depends on FAULT_INJECTION && BLOCK
966 help
967 Provide fault-injection capability for disk IO.
969 config FAIL_IO_TIMEOUT
970 bool "Fault-injection capability for faking disk interrupts"
971 depends on FAULT_INJECTION && BLOCK
972 help
973 Provide fault-injection capability on end IO handling. This
974 will make the block layer "forget" an interrupt as configured,
975 thus exercising the error handling.
977 Only works with drivers that use the generic timeout handling,
978 for others it wont do anything.
980 config FAULT_INJECTION_DEBUG_FS
981 bool "Debugfs entries for fault-injection capabilities"
982 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
983 help
984 Enable configuration of fault-injection capabilities via debugfs.
986 config FAULT_INJECTION_STACKTRACE_FILTER
987 bool "stacktrace filter for fault-injection capabilities"
988 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
989 depends on !X86_64
990 select STACKTRACE
991 select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE
992 help
993 Provide stacktrace filter for fault-injection capabilities
995 config LATENCYTOP
996 bool "Latency measuring infrastructure"
997 depends on HAVE_LATENCYTOP_SUPPORT
998 depends on DEBUG_KERNEL
999 depends on STACKTRACE_SUPPORT
1000 depends on PROC_FS
1001 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE
1002 select KALLSYMS
1003 select KALLSYMS_ALL
1004 select STACKTRACE
1005 select SCHEDSTATS
1006 select SCHED_DEBUG
1007 help
1008 Enable this option if you want to use the LatencyTOP tool
1009 to find out which userspace is blocking on what kernel operations.
1011 config SYSCTL_SYSCALL_CHECK
1012 bool "Sysctl checks"
1013 depends on SYSCTL
1014 ---help---
1015 sys_sysctl uses binary paths that have been found challenging
1016 to properly maintain and use. This enables checks that help
1017 you to keep things correct.
1019 source mm/Kconfig.debug
1020 source kernel/trace/Kconfig
1022 config PROVIDE_OHCI1394_DMA_INIT
1023 bool "Remote debugging over FireWire early on boot"
1024 depends on PCI && X86
1025 help
1026 If you want to debug problems which hang or crash the kernel early
1027 on boot and the crashing machine has a FireWire port, you can use
1028 this feature to remotely access the memory of the crashed machine
1029 over FireWire. This employs remote DMA as part of the OHCI1394
1030 specification which is now the standard for FireWire controllers.
1032 With remote DMA, you can monitor the printk buffer remotely using
1033 firescope and access all memory below 4GB using fireproxy from gdb.
1034 Even controlling a kernel debugger is possible using remote DMA.
1036 Usage:
1038 If ohci1394_dma=early is used as boot parameter, it will initialize
1039 all OHCI1394 controllers which are found in the PCI config space.
1041 As all changes to the FireWire bus such as enabling and disabling
1042 devices cause a bus reset and thereby disable remote DMA for all
1043 devices, be sure to have the cable plugged and FireWire enabled on
1044 the debugging host before booting the debug target for debugging.
1046 This code (~1k) is freed after boot. By then, the firewire stack
1047 in charge of the OHCI-1394 controllers should be used instead.
1049 See Documentation/debugging-via-ohci1394.txt for more information.
1051 config FIREWIRE_OHCI_REMOTE_DMA
1052 bool "Remote debugging over FireWire with firewire-ohci"
1053 depends on FIREWIRE_OHCI
1054 help
1055 This option lets you use the FireWire bus for remote debugging
1056 with help of the firewire-ohci driver. It enables unfiltered
1057 remote DMA in firewire-ohci.
1058 See Documentation/debugging-via-ohci1394.txt for more information.
1060 If unsure, say N.
1062 config BUILD_DOCSRC
1063 bool "Build targets in Documentation/ tree"
1064 depends on HEADERS_CHECK
1065 help
1066 This option attempts to build objects from the source files in the
1067 kernel Documentation/ tree.
1069 Say N if you are unsure.
1071 config DYNAMIC_DEBUG
1072 bool "Enable dynamic printk() support"
1073 default n
1074 depends on PRINTK
1075 depends on DEBUG_FS
1076 help
1078 Compiles debug level messages into the kernel, which would not
1079 otherwise be available at runtime. These messages can then be
1080 enabled/disabled based on various levels of scope - per source file,
1081 function, module, format string, and line number. This mechanism
1082 implicitly enables all pr_debug() and dev_dbg() calls. The impact of
1083 this compile option is a larger kernel text size of about 2%.
1085 Usage:
1087 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
1088 which is contained in the 'debugfs' filesystem. Thus, the debugfs
1089 filesystem must first be mounted before making use of this feature.
1090 We refer the control file as: <debugfs>/dynamic_debug/control. This
1091 file contains a list of the debug statements that can be enabled. The
1092 format for each line of the file is:
1094 filename:lineno [module]function flags format
1096 filename : source file of the debug statement
1097 lineno : line number of the debug statement
1098 module : module that contains the debug statement
1099 function : function that contains the debug statement
1100 flags : 'p' means the line is turned 'on' for printing
1101 format : the format used for the debug statement
1103 From a live system:
1105 nullarbor:~ # cat <debugfs>/dynamic_debug/control
1106 # filename:lineno [module]function flags format
1107 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
1108 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
1109 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
1111 Example usage:
1113 // enable the message at line 1603 of file svcsock.c
1114 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
1115 <debugfs>/dynamic_debug/control
1117 // enable all the messages in file svcsock.c
1118 nullarbor:~ # echo -n 'file svcsock.c +p' >
1119 <debugfs>/dynamic_debug/control
1121 // enable all the messages in the NFS server module
1122 nullarbor:~ # echo -n 'module nfsd +p' >
1123 <debugfs>/dynamic_debug/control
1125 // enable all 12 messages in the function svc_process()
1126 nullarbor:~ # echo -n 'func svc_process +p' >
1127 <debugfs>/dynamic_debug/control
1129 // disable all 12 messages in the function svc_process()
1130 nullarbor:~ # echo -n 'func svc_process -p' >
1131 <debugfs>/dynamic_debug/control
1133 See Documentation/dynamic-debug-howto.txt for additional information.
1135 config DMA_API_DEBUG
1136 bool "Enable debugging of DMA-API usage"
1137 depends on HAVE_DMA_API_DEBUG
1138 help
1139 Enable this option to debug the use of the DMA API by device drivers.
1140 With this option you will be able to detect common bugs in device
1141 drivers like double-freeing of DMA mappings or freeing mappings that
1142 were never allocated.
1143 This option causes a performance degredation. Use only if you want
1144 to debug device drivers. If unsure, say N.
1146 config ATOMIC64_SELFTEST
1147 bool "Perform an atomic64_t self-test at boot"
1148 help
1149 Enable this option to test the atomic64_t functions at boot.
1151 If unsure, say N.
1153 source "samples/Kconfig"
1155 source "lib/Kconfig.kgdb"
1157 source "lib/Kconfig.kmemcheck"