| blob | 234ceb10861f304ba858ec9a0baa9f6b297a43a6 |
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 depends on SYSFS
80 help
81 debugfs is a virtual file system that kernel developers use to put
82 debugging files into. Enable this option to be able to read and
83 write to these files.
85 For detailed documentation on the debugfs API, see
86 Documentation/DocBook/filesystems.
88 If unsure, say N.
90 config HEADERS_CHECK
91 bool "Run 'make headers_check' when building vmlinux"
92 depends on !UML
93 help
94 This option will extract the user-visible kernel headers whenever
95 building the kernel, and will run basic sanity checks on them to
96 ensure that exported files do not attempt to include files which
97 were not exported, etc.
99 If you're making modifications to header files which are
100 relevant for userspace, say 'Y', and check the headers
101 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
102 your build tree), to make sure they're suitable.
104 config DEBUG_SECTION_MISMATCH
105 bool "Enable full Section mismatch analysis"
106 depends on UNDEFINED
107 # This option is on purpose disabled for now.
108 # It will be enabled when we are down to a resonable 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 DETECT_SOFTLOCKUP
155 bool "Detect Soft Lockups"
156 depends on DEBUG_KERNEL && !S390
157 default y
158 help
159 Say Y here to enable the kernel to detect "soft lockups",
160 which are bugs that cause the kernel to loop in kernel
161 mode for more than 60 seconds, without giving other tasks a
162 chance to run.
164 When a soft-lockup is detected, the kernel will print the
165 current stack trace (which you should report), but the
166 system will stay locked up. This feature has negligible
167 overhead.
169 (Note that "hard lockups" are separate type of bugs that
170 can be detected via the NMI-watchdog, on platforms that
171 support it.)
173 config BOOTPARAM_SOFTLOCKUP_PANIC
174 bool "Panic (Reboot) On Soft Lockups"
175 depends on DETECT_SOFTLOCKUP
176 help
177 Say Y here to enable the kernel to panic on "soft lockups",
178 which are bugs that cause the kernel to loop in kernel
179 mode for more than 60 seconds, without giving other tasks a
180 chance to run.
182 The panic can be used in combination with panic_timeout,
183 to cause the system to reboot automatically after a
184 lockup has been detected. This feature is useful for
185 high-availability systems that have uptime guarantees and
186 where a lockup must be resolved ASAP.
188 Say N if unsure.
190 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
191 int
192 depends on DETECT_SOFTLOCKUP
193 range 0 1
194 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
195 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
197 config DETECT_HUNG_TASK
198 bool "Detect Hung Tasks"
199 depends on DEBUG_KERNEL
200 default DETECT_SOFTLOCKUP
201 help
202 Say Y here to enable the kernel to detect "hung tasks",
203 which are bugs that cause the task to be stuck in
204 uninterruptible "D" state indefinitiley.
206 When a hung task is detected, the kernel will print the
207 current stack trace (which you should report), but the
208 task will stay in uninterruptible state. If lockdep is
209 enabled then all held locks will also be reported. This
210 feature has negligible overhead.
212 config BOOTPARAM_HUNG_TASK_PANIC
213 bool "Panic (Reboot) On Hung Tasks"
214 depends on DETECT_HUNG_TASK
215 help
216 Say Y here to enable the kernel to panic on "hung tasks",
217 which are bugs that cause the kernel to leave a task stuck
218 in uninterruptible "D" state.
220 The panic can be used in combination with panic_timeout,
221 to cause the system to reboot automatically after a
222 hung task has been detected. This feature is useful for
223 high-availability systems that have uptime guarantees and
224 where a hung tasks must be resolved ASAP.
226 Say N if unsure.
228 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
229 int
230 depends on DETECT_HUNG_TASK
231 range 0 1
232 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
233 default 1 if BOOTPARAM_HUNG_TASK_PANIC
235 config SCHED_DEBUG
236 bool "Collect scheduler debugging info"
237 depends on DEBUG_KERNEL && PROC_FS
238 default y
239 help
240 If you say Y here, the /proc/sched_debug file will be provided
241 that can help debug the scheduler. The runtime overhead of this
242 option is minimal.
244 config SCHEDSTATS
245 bool "Collect scheduler statistics"
246 depends on DEBUG_KERNEL && PROC_FS
247 help
248 If you say Y here, additional code will be inserted into the
249 scheduler and related routines to collect statistics about
250 scheduler behavior and provide them in /proc/schedstat. These
251 stats may be useful for both tuning and debugging the scheduler
252 If you aren't debugging the scheduler or trying to tune a specific
253 application, you can say N to avoid the very slight overhead
254 this adds.
256 config TIMER_STATS
257 bool "Collect kernel timers statistics"
258 depends on DEBUG_KERNEL && PROC_FS
259 help
260 If you say Y here, additional code will be inserted into the
261 timer routines to collect statistics about kernel timers being
262 reprogrammed. The statistics can be read from /proc/timer_stats.
263 The statistics collection is started by writing 1 to /proc/timer_stats,
264 writing 0 stops it. This feature is useful to collect information
265 about timer usage patterns in kernel and userspace. This feature
266 is lightweight if enabled in the kernel config but not activated
267 (it defaults to deactivated on bootup and will only be activated
268 if some application like powertop activates it explicitly).
270 config DEBUG_OBJECTS
271 bool "Debug object operations"
272 depends on DEBUG_KERNEL
273 help
274 If you say Y here, additional code will be inserted into the
275 kernel to track the life time of various objects and validate
276 the operations on those objects.
278 config DEBUG_OBJECTS_SELFTEST
279 bool "Debug objects selftest"
280 depends on DEBUG_OBJECTS
281 help
282 This enables the selftest of the object debug code.
284 config DEBUG_OBJECTS_FREE
285 bool "Debug objects in freed memory"
286 depends on DEBUG_OBJECTS
287 help
288 This enables checks whether a k/v free operation frees an area
289 which contains an object which has not been deactivated
290 properly. This can make kmalloc/kfree-intensive workloads
291 much slower.
293 config DEBUG_OBJECTS_TIMERS
294 bool "Debug timer objects"
295 depends on DEBUG_OBJECTS
296 help
297 If you say Y here, additional code will be inserted into the
298 timer routines to track the life time of timer objects and
299 validate the timer operations.
301 config DEBUG_OBJECTS_ENABLE_DEFAULT
302 int "debug_objects bootup default value (0-1)"
303 range 0 1
304 default "1"
305 depends on DEBUG_OBJECTS
306 help
307 Debug objects boot parameter default value
309 config DEBUG_SLAB
310 bool "Debug slab memory allocations"
311 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
312 help
313 Say Y here to have the kernel do limited verification on memory
314 allocation as well as poisoning memory on free to catch use of freed
315 memory. This can make kmalloc/kfree-intensive workloads much slower.
317 config DEBUG_SLAB_LEAK
318 bool "Memory leak debugging"
319 depends on DEBUG_SLAB
321 config SLUB_DEBUG_ON
322 bool "SLUB debugging on by default"
323 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
324 default n
325 help
326 Boot with debugging on by default. SLUB boots by default with
327 the runtime debug capabilities switched off. Enabling this is
328 equivalent to specifying the "slub_debug" parameter on boot.
329 There is no support for more fine grained debug control like
330 possible with slub_debug=xxx. SLUB debugging may be switched
331 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
332 "slub_debug=-".
334 config SLUB_STATS
335 default n
336 bool "Enable SLUB performance statistics"
337 depends on SLUB && SLUB_DEBUG && SYSFS
338 help
339 SLUB statistics are useful to debug SLUBs allocation behavior in
340 order find ways to optimize the allocator. This should never be
341 enabled for production use since keeping statistics slows down
342 the allocator by a few percentage points. The slabinfo command
343 supports the determination of the most active slabs to figure
344 out which slabs are relevant to a particular load.
345 Try running: slabinfo -DA
347 config DEBUG_KMEMLEAK
348 bool "Kernel memory leak detector"
349 depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
350 (X86 || ARM || PPC || S390)
352 select DEBUG_FS if SYSFS
353 select STACKTRACE if STACKTRACE_SUPPORT
354 select KALLSYMS
355 help
356 Say Y here if you want to enable the memory leak
357 detector. The memory allocation/freeing is traced in a way
358 similar to the Boehm's conservative garbage collector, the
359 difference being that the orphan objects are not freed but
360 only shown in /sys/kernel/debug/kmemleak. Enabling this
361 feature will introduce an overhead to memory
362 allocations. See Documentation/kmemleak.txt for more
363 details.
365 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
366 of finding leaks due to the slab objects poisoning.
368 In order to access the kmemleak file, debugfs needs to be
369 mounted (usually at /sys/kernel/debug).
371 config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
372 int "Maximum kmemleak early log entries"
373 depends on DEBUG_KMEMLEAK
374 range 200 40000
375 default 400
376 help
377 Kmemleak must track all the memory allocations to avoid
378 reporting false positives. Since memory may be allocated or
379 freed before kmemleak is initialised, an early log buffer is
380 used to store these actions. If kmemleak reports "early log
381 buffer exceeded", please increase this value.
383 config DEBUG_KMEMLEAK_TEST
384 tristate "Simple test for the kernel memory leak detector"
385 depends on DEBUG_KMEMLEAK
386 help
387 Say Y or M here to build a test for the kernel memory leak
388 detector. This option enables a module that explicitly leaks
389 memory.
391 If unsure, say N.
393 config DEBUG_PREEMPT
394 bool "Debug preemptible kernel"
395 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
396 default y
397 help
398 If you say Y here then the kernel will use a debug variant of the
399 commonly used smp_processor_id() function and will print warnings
400 if kernel code uses it in a preemption-unsafe way. Also, the kernel
401 will detect preemption count underflows.
403 config DEBUG_RT_MUTEXES
404 bool "RT Mutex debugging, deadlock detection"
405 depends on DEBUG_KERNEL && RT_MUTEXES
406 help
407 This allows rt mutex semantics violations and rt mutex related
408 deadlocks (lockups) to be detected and reported automatically.
410 config DEBUG_PI_LIST
411 bool
412 default y
413 depends on DEBUG_RT_MUTEXES
415 config RT_MUTEX_TESTER
416 bool "Built-in scriptable tester for rt-mutexes"
417 depends on DEBUG_KERNEL && RT_MUTEXES
418 help
419 This option enables a rt-mutex tester.
421 config DEBUG_SPINLOCK
422 bool "Spinlock and rw-lock debugging: basic checks"
423 depends on DEBUG_KERNEL
424 help
425 Say Y here and build SMP to catch missing spinlock initialization
426 and certain other kinds of spinlock errors commonly made. This is
427 best used in conjunction with the NMI watchdog so that spinlock
428 deadlocks are also debuggable.
430 config DEBUG_MUTEXES
431 bool "Mutex debugging: basic checks"
432 depends on DEBUG_KERNEL
433 help
434 This feature allows mutex semantics violations to be detected and
435 reported.
437 config DEBUG_LOCK_ALLOC
438 bool "Lock debugging: detect incorrect freeing of live locks"
439 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
440 select DEBUG_SPINLOCK
441 select DEBUG_MUTEXES
442 select LOCKDEP
443 help
444 This feature will check whether any held lock (spinlock, rwlock,
445 mutex or rwsem) is incorrectly freed by the kernel, via any of the
446 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
447 vfree(), etc.), whether a live lock is incorrectly reinitialized via
448 spin_lock_init()/mutex_init()/etc., or whether there is any lock
449 held during task exit.
451 config PROVE_LOCKING
452 bool "Lock debugging: prove locking correctness"
453 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
454 select LOCKDEP
455 select DEBUG_SPINLOCK
456 select DEBUG_MUTEXES
457 select DEBUG_LOCK_ALLOC
458 default n
459 help
460 This feature enables the kernel to prove that all locking
461 that occurs in the kernel runtime is mathematically
462 correct: that under no circumstance could an arbitrary (and
463 not yet triggered) combination of observed locking
464 sequences (on an arbitrary number of CPUs, running an
465 arbitrary number of tasks and interrupt contexts) cause a
466 deadlock.
468 In short, this feature enables the kernel to report locking
469 related deadlocks before they actually occur.
471 The proof does not depend on how hard and complex a
472 deadlock scenario would be to trigger: how many
473 participant CPUs, tasks and irq-contexts would be needed
474 for it to trigger. The proof also does not depend on
475 timing: if a race and a resulting deadlock is possible
476 theoretically (no matter how unlikely the race scenario
477 is), it will be proven so and will immediately be
478 reported by the kernel (once the event is observed that
479 makes the deadlock theoretically possible).
481 If a deadlock is impossible (i.e. the locking rules, as
482 observed by the kernel, are mathematically correct), the
483 kernel reports nothing.
485 NOTE: this feature can also be enabled for rwlocks, mutexes
486 and rwsems - in which case all dependencies between these
487 different locking variants are observed and mapped too, and
488 the proof of observed correctness is also maintained for an
489 arbitrary combination of these separate locking variants.
491 For more details, see Documentation/lockdep-design.txt.
493 config LOCKDEP
494 bool
495 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
496 select STACKTRACE
497 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390
498 select KALLSYMS
499 select KALLSYMS_ALL
501 config LOCK_STAT
502 bool "Lock usage statistics"
503 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
504 select LOCKDEP
505 select DEBUG_SPINLOCK
506 select DEBUG_MUTEXES
507 select DEBUG_LOCK_ALLOC
508 default n
509 help
510 This feature enables tracking lock contention points
512 For more details, see Documentation/lockstat.txt
514 config DEBUG_LOCKDEP
515 bool "Lock dependency engine debugging"
516 depends on DEBUG_KERNEL && LOCKDEP
517 help
518 If you say Y here, the lock dependency engine will do
519 additional runtime checks to debug itself, at the price
520 of more runtime overhead.
522 config TRACE_IRQFLAGS
523 depends on DEBUG_KERNEL
524 bool
525 default y
526 depends on TRACE_IRQFLAGS_SUPPORT
527 depends on PROVE_LOCKING
529 config DEBUG_SPINLOCK_SLEEP
530 bool "Spinlock debugging: sleep-inside-spinlock checking"
531 depends on DEBUG_KERNEL
532 help
533 If you say Y here, various routines which may sleep will become very
534 noisy if they are called with a spinlock held.
536 config DEBUG_LOCKING_API_SELFTESTS
537 bool "Locking API boot-time self-tests"
538 depends on DEBUG_KERNEL
539 help
540 Say Y here if you want the kernel to run a short self-test during
541 bootup. The self-test checks whether common types of locking bugs
542 are detected by debugging mechanisms or not. (if you disable
543 lock debugging then those bugs wont be detected of course.)
544 The following locking APIs are covered: spinlocks, rwlocks,
545 mutexes and rwsems.
547 config STACKTRACE
548 bool
549 depends on STACKTRACE_SUPPORT
551 config DEBUG_KOBJECT
552 bool "kobject debugging"
553 depends on DEBUG_KERNEL
554 help
555 If you say Y here, some extra kobject debugging messages will be sent
556 to the syslog.
558 config DEBUG_HIGHMEM
559 bool "Highmem debugging"
560 depends on DEBUG_KERNEL && HIGHMEM
561 help
562 This options enables addition error checking for high memory systems.
563 Disable for production systems.
565 config DEBUG_BUGVERBOSE
566 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
567 depends on BUG
568 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
569 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
570 default !EMBEDDED
571 help
572 Say Y here to make BUG() panics output the file name and line number
573 of the BUG call as well as the EIP and oops trace. This aids
574 debugging but costs about 70-100K of memory.
576 config DEBUG_INFO
577 bool "Compile the kernel with debug info"
578 depends on DEBUG_KERNEL
579 help
580 If you say Y here the resulting kernel image will include
581 debugging info resulting in a larger kernel image.
582 This adds debug symbols to the kernel and modules (gcc -g), and
583 is needed if you intend to use kernel crashdump or binary object
584 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
585 Say Y here only if you plan to debug the kernel.
587 If unsure, say N.
589 config DEBUG_VM
590 bool "Debug VM"
591 depends on DEBUG_KERNEL
592 help
593 Enable this to turn on extended checks in the virtual-memory system
594 that may impact performance.
596 If unsure, say N.
598 config DEBUG_VIRTUAL
599 bool "Debug VM translations"
600 depends on DEBUG_KERNEL && X86
601 help
602 Enable some costly sanity checks in virtual to page code. This can
603 catch mistakes with virt_to_page() and friends.
605 If unsure, say N.
607 config DEBUG_NOMMU_REGIONS
608 bool "Debug the global anon/private NOMMU mapping region tree"
609 depends on DEBUG_KERNEL && !MMU
610 help
611 This option causes the global tree of anonymous and private mapping
612 regions to be regularly checked for invalid topology.
614 config DEBUG_WRITECOUNT
615 bool "Debug filesystem writers count"
616 depends on DEBUG_KERNEL
617 help
618 Enable this to catch wrong use of the writers count in struct
619 vfsmount. This will increase the size of each file struct by
620 32 bits.
622 If unsure, say N.
624 config DEBUG_MEMORY_INIT
625 bool "Debug memory initialisation" if EMBEDDED
626 default !EMBEDDED
627 help
628 Enable this for additional checks during memory initialisation.
629 The sanity checks verify aspects of the VM such as the memory model
630 and other information provided by the architecture. Verbose
631 information will be printed at KERN_DEBUG loglevel depending
632 on the mminit_loglevel= command-line option.
634 If unsure, say Y
636 config DEBUG_LIST
637 bool "Debug linked list manipulation"
638 depends on DEBUG_KERNEL
639 help
640 Enable this to turn on extended checks in the linked-list
641 walking routines.
643 If unsure, say N.
645 config DEBUG_SG
646 bool "Debug SG table operations"
647 depends on DEBUG_KERNEL
648 help
649 Enable this to turn on checks on scatter-gather tables. This can
650 help find problems with drivers that do not properly initialize
651 their sg tables.
653 If unsure, say N.
655 config DEBUG_NOTIFIERS
656 bool "Debug notifier call chains"
657 depends on DEBUG_KERNEL
658 help
659 Enable this to turn on sanity checking for notifier call chains.
660 This is most useful for kernel developers to make sure that
661 modules properly unregister themselves from notifier chains.
662 This is a relatively cheap check but if you care about maximum
663 performance, say N.
665 config DEBUG_CREDENTIALS
666 bool "Debug credential management"
667 depends on DEBUG_KERNEL
668 help
669 Enable this to turn on some debug checking for credential
670 management. The additional code keeps track of the number of
671 pointers from task_structs to any given cred struct, and checks to
672 see that this number never exceeds the usage count of the cred
673 struct.
675 Furthermore, if SELinux is enabled, this also checks that the
676 security pointer in the cred struct is never seen to be invalid.
678 If unsure, say N.
680 #
681 # Select this config option from the architecture Kconfig, if it
682 # it is preferred to always offer frame pointers as a config
683 # option on the architecture (regardless of KERNEL_DEBUG):
684 #
685 config ARCH_WANT_FRAME_POINTERS
686 bool
687 help
689 config FRAME_POINTER
690 bool "Compile the kernel with frame pointers"
691 depends on DEBUG_KERNEL && \
692 (CRIS || M68K || M68KNOMMU || FRV || UML || \
693 AVR32 || SUPERH || BLACKFIN || MN10300) || \
694 ARCH_WANT_FRAME_POINTERS
695 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
696 help
697 If you say Y here the resulting kernel image will be slightly
698 larger and slower, but it gives very useful debugging information
699 in case of kernel bugs. (precise oopses/stacktraces/warnings)
701 config BOOT_PRINTK_DELAY
702 bool "Delay each boot printk message by N milliseconds"
703 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
704 help
705 This build option allows you to read kernel boot messages
706 by inserting a short delay after each one. The delay is
707 specified in milliseconds on the kernel command line,
708 using "boot_delay=N".
710 It is likely that you would also need to use "lpj=M" to preset
711 the "loops per jiffie" value.
712 See a previous boot log for the "lpj" value to use for your
713 system, and then set "lpj=M" before setting "boot_delay=N".
714 NOTE: Using this option may adversely affect SMP systems.
715 I.e., processors other than the first one may not boot up.
716 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
717 what it believes to be lockup conditions.
719 config RCU_TORTURE_TEST
720 tristate "torture tests for RCU"
721 depends on DEBUG_KERNEL
722 default n
723 help
724 This option provides a kernel module that runs torture tests
725 on the RCU infrastructure. The kernel module may be built
726 after the fact on the running kernel to be tested, if desired.
728 Say Y here if you want RCU torture tests to be built into
729 the kernel.
730 Say M if you want the RCU torture tests to build as a module.
731 Say N if you are unsure.
733 config RCU_TORTURE_TEST_RUNNABLE
734 bool "torture tests for RCU runnable by default"
735 depends on RCU_TORTURE_TEST = y
736 default n
737 help
738 This option provides a way to build the RCU torture tests
739 directly into the kernel without them starting up at boot
740 time. You can use /proc/sys/kernel/rcutorture_runnable
741 to manually override this setting. This /proc file is
742 available only when the RCU torture tests have been built
743 into the kernel.
745 Say Y here if you want the RCU torture tests to start during
746 boot (you probably don't).
747 Say N here if you want the RCU torture tests to start only
748 after being manually enabled via /proc.
750 config RCU_CPU_STALL_DETECTOR
751 bool "Check for stalled CPUs delaying RCU grace periods"
752 depends on TREE_RCU || TREE_PREEMPT_RCU
753 default n
754 help
755 This option causes RCU to printk information on which
756 CPUs are delaying the current grace period, but only when
757 the grace period extends for excessive time periods.
759 Say Y if you want RCU to perform such checks.
761 Say N if you are unsure.
763 config KPROBES_SANITY_TEST
764 bool "Kprobes sanity tests"
765 depends on DEBUG_KERNEL
766 depends on KPROBES
767 default n
768 help
769 This option provides for testing basic kprobes functionality on
770 boot. A sample kprobe, jprobe and kretprobe are inserted and
771 verified for functionality.
773 Say N if you are unsure.
775 config BACKTRACE_SELF_TEST
776 tristate "Self test for the backtrace code"
777 depends on DEBUG_KERNEL
778 default n
779 help
780 This option provides a kernel module that can be used to test
781 the kernel stack backtrace code. This option is not useful
782 for distributions or general kernels, but only for kernel
783 developers working on architecture code.
785 Note that if you want to also test saved backtraces, you will
786 have to enable STACKTRACE as well.
788 Say N if you are unsure.
790 config DEBUG_BLOCK_EXT_DEVT
791 bool "Force extended block device numbers and spread them"
792 depends on DEBUG_KERNEL
793 depends on BLOCK
794 default n
795 help
796 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
797 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
798 YOU ARE DOING. Distros, please enable this and fix whatever
799 is broken.
801 Conventionally, block device numbers are allocated from
802 predetermined contiguous area. However, extended block area
803 may introduce non-contiguous block device numbers. This
804 option forces most block device numbers to be allocated from
805 the extended space and spreads them to discover kernel or
806 userland code paths which assume predetermined contiguous
807 device number allocation.
809 Note that turning on this debug option shuffles all the
810 device numbers for all IDE and SCSI devices including libata
811 ones, so root partition specified using device number
812 directly (via rdev or root=MAJ:MIN) won't work anymore.
813 Textual device names (root=/dev/sdXn) will continue to work.
815 Say N if you are unsure.
817 config DEBUG_FORCE_WEAK_PER_CPU
818 bool "Force weak per-cpu definitions"
819 depends on DEBUG_KERNEL
820 help
821 s390 and alpha require percpu variables in modules to be
822 defined weak to work around addressing range issue which
823 puts the following two restrictions on percpu variable
824 definitions.
826 1. percpu symbols must be unique whether static or not
827 2. percpu variables can't be defined inside a function
829 To ensure that generic code follows the above rules, this
830 option forces all percpu variables to be defined as weak.
832 config LKDTM
833 tristate "Linux Kernel Dump Test Tool Module"
834 depends on DEBUG_KERNEL
835 depends on KPROBES
836 depends on BLOCK
837 default n
838 help
839 This module enables testing of the different dumping mechanisms by
840 inducing system failures at predefined crash points.
841 If you don't need it: say N
842 Choose M here to compile this code as a module. The module will be
843 called lkdtm.
845 Documentation on how to use the module can be found in
846 drivers/misc/lkdtm.c
848 config FAULT_INJECTION
849 bool "Fault-injection framework"
850 depends on DEBUG_KERNEL
851 help
852 Provide fault-injection framework.
853 For more details, see Documentation/fault-injection/.
855 config FAILSLAB
856 bool "Fault-injection capability for kmalloc"
857 depends on FAULT_INJECTION
858 depends on SLAB || SLUB
859 help
860 Provide fault-injection capability for kmalloc.
862 config FAIL_PAGE_ALLOC
863 bool "Fault-injection capabilitiy for alloc_pages()"
864 depends on FAULT_INJECTION
865 help
866 Provide fault-injection capability for alloc_pages().
868 config FAIL_MAKE_REQUEST
869 bool "Fault-injection capability for disk IO"
870 depends on FAULT_INJECTION && BLOCK
871 help
872 Provide fault-injection capability for disk IO.
874 config FAIL_IO_TIMEOUT
875 bool "Faul-injection capability for faking disk interrupts"
876 depends on FAULT_INJECTION && BLOCK
877 help
878 Provide fault-injection capability on end IO handling. This
879 will make the block layer "forget" an interrupt as configured,
880 thus exercising the error handling.
882 Only works with drivers that use the generic timeout handling,
883 for others it wont do anything.
885 config FAULT_INJECTION_DEBUG_FS
886 bool "Debugfs entries for fault-injection capabilities"
887 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
888 help
889 Enable configuration of fault-injection capabilities via debugfs.
891 config FAULT_INJECTION_STACKTRACE_FILTER
892 bool "stacktrace filter for fault-injection capabilities"
893 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
894 depends on !X86_64
895 select STACKTRACE
896 select FRAME_POINTER if !PPC && !S390
897 help
898 Provide stacktrace filter for fault-injection capabilities
900 config LATENCYTOP
901 bool "Latency measuring infrastructure"
902 select FRAME_POINTER if !MIPS && !PPC && !S390
903 select KALLSYMS
904 select KALLSYMS_ALL
905 select STACKTRACE
906 select SCHEDSTATS
907 select SCHED_DEBUG
908 depends on HAVE_LATENCYTOP_SUPPORT
909 help
910 Enable this option if you want to use the LatencyTOP tool
911 to find out which userspace is blocking on what kernel operations.
913 config SYSCTL_SYSCALL_CHECK
914 bool "Sysctl checks"
915 depends on SYSCTL_SYSCALL
916 ---help---
917 sys_sysctl uses binary paths that have been found challenging
918 to properly maintain and use. This enables checks that help
919 you to keep things correct.
921 source mm/Kconfig.debug
922 source kernel/trace/Kconfig
924 config PROVIDE_OHCI1394_DMA_INIT
925 bool "Remote debugging over FireWire early on boot"
926 depends on PCI && X86
927 help
928 If you want to debug problems which hang or crash the kernel early
929 on boot and the crashing machine has a FireWire port, you can use
930 this feature to remotely access the memory of the crashed machine
931 over FireWire. This employs remote DMA as part of the OHCI1394
932 specification which is now the standard for FireWire controllers.
934 With remote DMA, you can monitor the printk buffer remotely using
935 firescope and access all memory below 4GB using fireproxy from gdb.
936 Even controlling a kernel debugger is possible using remote DMA.
938 Usage:
940 If ohci1394_dma=early is used as boot parameter, it will initialize
941 all OHCI1394 controllers which are found in the PCI config space.
943 As all changes to the FireWire bus such as enabling and disabling
944 devices cause a bus reset and thereby disable remote DMA for all
945 devices, be sure to have the cable plugged and FireWire enabled on
946 the debugging host before booting the debug target for debugging.
948 This code (~1k) is freed after boot. By then, the firewire stack
949 in charge of the OHCI-1394 controllers should be used instead.
951 See Documentation/debugging-via-ohci1394.txt for more information.
953 config FIREWIRE_OHCI_REMOTE_DMA
954 bool "Remote debugging over FireWire with firewire-ohci"
955 depends on FIREWIRE_OHCI
956 help
957 This option lets you use the FireWire bus for remote debugging
958 with help of the firewire-ohci driver. It enables unfiltered
959 remote DMA in firewire-ohci.
960 See Documentation/debugging-via-ohci1394.txt for more information.
962 If unsure, say N.
964 config BUILD_DOCSRC
965 bool "Build targets in Documentation/ tree"
966 depends on HEADERS_CHECK
967 help
968 This option attempts to build objects from the source files in the
969 kernel Documentation/ tree.
971 Say N if you are unsure.
973 config DYNAMIC_DEBUG
974 bool "Enable dynamic printk() support"
975 default n
976 depends on PRINTK
977 depends on DEBUG_FS
978 help
980 Compiles debug level messages into the kernel, which would not
981 otherwise be available at runtime. These messages can then be
982 enabled/disabled based on various levels of scope - per source file,
983 function, module, format string, and line number. This mechanism
984 implicitly enables all pr_debug() and dev_dbg() calls. The impact of
985 this compile option is a larger kernel text size of about 2%.
987 Usage:
989 Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file,
990 which is contained in the 'debugfs' filesystem. Thus, the debugfs
991 filesystem must first be mounted before making use of this feature.
992 We refer the control file as: <debugfs>/dynamic_debug/ddebug. This
993 file contains a list of the debug statements that can be enabled. The
994 format for each line of the file is:
996 filename:lineno [module]function flags format
998 filename : source file of the debug statement
999 lineno : line number of the debug statement
1000 module : module that contains the debug statement
1001 function : function that contains the debug statement
1002 flags : 'p' means the line is turned 'on' for printing
1003 format : the format used for the debug statement
1005 From a live system:
1007 nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
1008 # filename:lineno [module]function flags format
1009 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
1010 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
1011 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
1013 Example usage:
1015 // enable the message at line 1603 of file svcsock.c
1016 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
1017 <debugfs>/dynamic_debug/ddebug
1019 // enable all the messages in file svcsock.c
1020 nullarbor:~ # echo -n 'file svcsock.c +p' >
1021 <debugfs>/dynamic_debug/ddebug
1023 // enable all the messages in the NFS server module
1024 nullarbor:~ # echo -n 'module nfsd +p' >
1025 <debugfs>/dynamic_debug/ddebug
1027 // enable all 12 messages in the function svc_process()
1028 nullarbor:~ # echo -n 'func svc_process +p' >
1029 <debugfs>/dynamic_debug/ddebug
1031 // disable all 12 messages in the function svc_process()
1032 nullarbor:~ # echo -n 'func svc_process -p' >
1033 <debugfs>/dynamic_debug/ddebug
1035 See Documentation/dynamic-debug-howto.txt for additional information.
1037 config DMA_API_DEBUG
1038 bool "Enable debugging of DMA-API usage"
1039 depends on HAVE_DMA_API_DEBUG
1040 help
1041 Enable this option to debug the use of the DMA API by device drivers.
1042 With this option you will be able to detect common bugs in device
1043 drivers like double-freeing of DMA mappings or freeing mappings that
1044 were never allocated.
1045 This option causes a performance degredation. Use only if you want
1046 to debug device drivers. If unsure, say N.
1048 source "samples/Kconfig"
1050 source "lib/Kconfig.kgdb"
1052 source "lib/Kconfig.kmemcheck"