| blob | 1501aa553221497a1d8e632439d75a36917fb687 |
1 menu "printk and dmesg options"
3 config PRINTK_TIME
4 bool "Show timing information on printks"
5 depends on PRINTK
6 help
7 Selecting this option causes time stamps of the printk()
8 messages to be added to the output of the syslog() system
9 call and at the console.
11 The timestamp is always recorded internally, and exported
12 to /dev/kmsg. This flag just specifies if the timestamp should
13 be included, not that the timestamp is recorded.
15 The behavior is also controlled by the kernel command line
16 parameter printk.time=1. See Documentation/kernel-parameters.txt
18 config DEFAULT_MESSAGE_LOGLEVEL
19 int "Default message log level (1-7)"
20 range 1 7
21 default "4"
22 help
23 Default log level for printk statements with no specified priority.
25 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
26 that are auditing their logs closely may want to set it to a lower
27 priority.
29 config BOOT_PRINTK_DELAY
30 bool "Delay each boot printk message by N milliseconds"
31 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
32 help
33 This build option allows you to read kernel boot messages
34 by inserting a short delay after each one. The delay is
35 specified in milliseconds on the kernel command line,
36 using "boot_delay=N".
38 It is likely that you would also need to use "lpj=M" to preset
39 the "loops per jiffie" value.
40 See a previous boot log for the "lpj" value to use for your
41 system, and then set "lpj=M" before setting "boot_delay=N".
42 NOTE: Using this option may adversely affect SMP systems.
43 I.e., processors other than the first one may not boot up.
44 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
45 what it believes to be lockup conditions.
47 config DYNAMIC_DEBUG
48 bool "Enable dynamic printk() support"
49 default n
50 depends on PRINTK
51 depends on DEBUG_FS
52 help
54 Compiles debug level messages into the kernel, which would not
55 otherwise be available at runtime. These messages can then be
56 enabled/disabled based on various levels of scope - per source file,
57 function, module, format string, and line number. This mechanism
58 implicitly compiles in all pr_debug() and dev_dbg() calls, which
59 enlarges the kernel text size by about 2%.
61 If a source file is compiled with DEBUG flag set, any
62 pr_debug() calls in it are enabled by default, but can be
63 disabled at runtime as below. Note that DEBUG flag is
64 turned on by many CONFIG_*DEBUG* options.
66 Usage:
68 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
69 which is contained in the 'debugfs' filesystem. Thus, the debugfs
70 filesystem must first be mounted before making use of this feature.
71 We refer the control file as: <debugfs>/dynamic_debug/control. This
72 file contains a list of the debug statements that can be enabled. The
73 format for each line of the file is:
75 filename:lineno [module]function flags format
77 filename : source file of the debug statement
78 lineno : line number of the debug statement
79 module : module that contains the debug statement
80 function : function that contains the debug statement
81 flags : '=p' means the line is turned 'on' for printing
82 format : the format used for the debug statement
84 From a live system:
86 nullarbor:~ # cat <debugfs>/dynamic_debug/control
87 # filename:lineno [module]function flags format
88 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
89 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
90 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
92 Example usage:
94 // enable the message at line 1603 of file svcsock.c
95 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
96 <debugfs>/dynamic_debug/control
98 // enable all the messages in file svcsock.c
99 nullarbor:~ # echo -n 'file svcsock.c +p' >
100 <debugfs>/dynamic_debug/control
102 // enable all the messages in the NFS server module
103 nullarbor:~ # echo -n 'module nfsd +p' >
104 <debugfs>/dynamic_debug/control
106 // enable all 12 messages in the function svc_process()
107 nullarbor:~ # echo -n 'func svc_process +p' >
108 <debugfs>/dynamic_debug/control
110 // disable all 12 messages in the function svc_process()
111 nullarbor:~ # echo -n 'func svc_process -p' >
112 <debugfs>/dynamic_debug/control
114 See Documentation/dynamic-debug-howto.txt for additional information.
116 endmenu # "printk and dmesg options"
118 menu "Compile-time checks and compiler options"
120 config DEBUG_INFO
121 bool "Compile the kernel with debug info"
122 depends on DEBUG_KERNEL
123 help
124 If you say Y here the resulting kernel image will include
125 debugging info resulting in a larger kernel image.
126 This adds debug symbols to the kernel and modules (gcc -g), and
127 is needed if you intend to use kernel crashdump or binary object
128 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
129 Say Y here only if you plan to debug the kernel.
131 If unsure, say N.
133 config DEBUG_INFO_REDUCED
134 bool "Reduce debugging information"
135 depends on DEBUG_INFO
136 help
137 If you say Y here gcc is instructed to generate less debugging
138 information for structure types. This means that tools that
139 need full debugging information (like kgdb or systemtap) won't
140 be happy. But if you merely need debugging information to
141 resolve line numbers there is no loss. Advantage is that
142 build directory object sizes shrink dramatically over a full
143 DEBUG_INFO build and compile times are reduced too.
144 Only works with newer gcc versions.
146 config ENABLE_WARN_DEPRECATED
147 bool "Enable __deprecated logic"
148 default y
149 help
150 Enable the __deprecated logic in the kernel build.
151 Disable this to suppress the "warning: 'foo' is deprecated
152 (declared at kernel/power/somefile.c:1234)" messages.
154 config ENABLE_MUST_CHECK
155 bool "Enable __must_check logic"
156 default y
157 help
158 Enable the __must_check logic in the kernel build. Disable this to
159 suppress the "warning: ignoring return value of 'foo', declared with
160 attribute warn_unused_result" messages.
162 config FRAME_WARN
163 int "Warn for stack frames larger than (needs gcc 4.4)"
164 range 0 8192
165 default 1024 if !64BIT
166 default 2048 if 64BIT
167 help
168 Tell gcc to warn at build time for stack frames larger than this.
169 Setting this too low will cause a lot of warnings.
170 Setting it to 0 disables the warning.
171 Requires gcc 4.4
173 config STRIP_ASM_SYMS
174 bool "Strip assembler-generated symbols during link"
175 default n
176 help
177 Strip internal assembler-generated symbols during a link (symbols
178 that look like '.Lxxx') so they don't pollute the output of
179 get_wchan() and suchlike.
181 config READABLE_ASM
182 bool "Generate readable assembler code"
183 depends on DEBUG_KERNEL
184 help
185 Disable some compiler optimizations that tend to generate human unreadable
186 assembler output. This may make the kernel slightly slower, but it helps
187 to keep kernel developers who have to stare a lot at assembler listings
188 sane.
190 config UNUSED_SYMBOLS
191 bool "Enable unused/obsolete exported symbols"
192 default y if X86
193 help
194 Unused but exported symbols make the kernel needlessly bigger. For
195 that reason most of these unused exports will soon be removed. This
196 option is provided temporarily to provide a transition period in case
197 some external kernel module needs one of these symbols anyway. If you
198 encounter such a case in your module, consider if you are actually
199 using the right API. (rationale: since nobody in the kernel is using
200 this in a module, there is a pretty good chance it's actually the
201 wrong interface to use). If you really need the symbol, please send a
202 mail to the linux kernel mailing list mentioning the symbol and why
203 you really need it, and what the merge plan to the mainline kernel for
204 your module is.
206 config DEBUG_FS
207 bool "Debug Filesystem"
208 help
209 debugfs is a virtual file system that kernel developers use to put
210 debugging files into. Enable this option to be able to read and
211 write to these files.
213 For detailed documentation on the debugfs API, see
214 Documentation/DocBook/filesystems.
216 If unsure, say N.
218 config HEADERS_CHECK
219 bool "Run 'make headers_check' when building vmlinux"
220 depends on !UML
221 help
222 This option will extract the user-visible kernel headers whenever
223 building the kernel, and will run basic sanity checks on them to
224 ensure that exported files do not attempt to include files which
225 were not exported, etc.
227 If you're making modifications to header files which are
228 relevant for userspace, say 'Y', and check the headers
229 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
230 your build tree), to make sure they're suitable.
232 config DEBUG_SECTION_MISMATCH
233 bool "Enable full Section mismatch analysis"
234 help
235 The section mismatch analysis checks if there are illegal
236 references from one section to another section.
237 During linktime or runtime, some sections are dropped;
238 any use of code/data previously in these sections would
239 most likely result in an oops.
240 In the code, functions and variables are annotated with
241 __init,, etc. (see the full list in include/linux/init.h),
242 which results in the code/data being placed in specific sections.
243 The section mismatch analysis is always performed after a full
244 kernel build, and enabling this option causes the following
245 additional steps to occur:
246 - Add the option -fno-inline-functions-called-once to gcc commands.
247 When inlining a function annotated with __init in a non-init
248 function, we would lose the section information and thus
249 the analysis would not catch the illegal reference.
250 This option tells gcc to inline less (but it does result in
251 a larger kernel).
252 - Run the section mismatch analysis for each module/built-in.o file.
253 When we run the section mismatch analysis on vmlinux.o, we
254 lose valueble information about where the mismatch was
255 introduced.
256 Running the analysis for each module/built-in.o file
257 tells where the mismatch happens much closer to the
258 source. The drawback is that the same mismatch is
259 reported at least twice.
260 - Enable verbose reporting from modpost in order to help resolve
261 the section mismatches that are reported.
263 #
264 # Select this config option from the architecture Kconfig, if it
265 # is preferred to always offer frame pointers as a config
266 # option on the architecture (regardless of KERNEL_DEBUG):
267 #
268 config ARCH_WANT_FRAME_POINTERS
269 bool
270 help
272 config FRAME_POINTER
273 bool "Compile the kernel with frame pointers"
274 depends on DEBUG_KERNEL && \
275 (CRIS || M68K || FRV || UML || \
276 AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \
277 ARCH_WANT_FRAME_POINTERS
278 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
279 help
280 If you say Y here the resulting kernel image will be slightly
281 larger and slower, but it gives very useful debugging information
282 in case of kernel bugs. (precise oopses/stacktraces/warnings)
284 config DEBUG_FORCE_WEAK_PER_CPU
285 bool "Force weak per-cpu definitions"
286 depends on DEBUG_KERNEL
287 help
288 s390 and alpha require percpu variables in modules to be
289 defined weak to work around addressing range issue which
290 puts the following two restrictions on percpu variable
291 definitions.
293 1. percpu symbols must be unique whether static or not
294 2. percpu variables can't be defined inside a function
296 To ensure that generic code follows the above rules, this
297 option forces all percpu variables to be defined as weak.
299 endmenu # "Compiler options"
301 config MAGIC_SYSRQ
302 bool "Magic SysRq key"
303 depends on !UML
304 help
305 If you say Y here, you will have some control over the system even
306 if the system crashes for example during kernel debugging (e.g., you
307 will be able to flush the buffer cache to disk, reboot the system
308 immediately or dump some status information). This is accomplished
309 by pressing various keys while holding SysRq (Alt+PrintScreen). It
310 also works on a serial console (on PC hardware at least), if you
311 send a BREAK and then within 5 seconds a command keypress. The
312 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
313 unless you really know what this hack does.
315 config DEBUG_KERNEL
316 bool "Kernel debugging"
317 help
318 Say Y here if you are developing drivers or trying to debug and
319 identify kernel problems.
321 menu "Memory Debugging"
323 source mm/Kconfig.debug
325 config DEBUG_OBJECTS
326 bool "Debug object operations"
327 depends on DEBUG_KERNEL
328 help
329 If you say Y here, additional code will be inserted into the
330 kernel to track the life time of various objects and validate
331 the operations on those objects.
333 config DEBUG_OBJECTS_SELFTEST
334 bool "Debug objects selftest"
335 depends on DEBUG_OBJECTS
336 help
337 This enables the selftest of the object debug code.
339 config DEBUG_OBJECTS_FREE
340 bool "Debug objects in freed memory"
341 depends on DEBUG_OBJECTS
342 help
343 This enables checks whether a k/v free operation frees an area
344 which contains an object which has not been deactivated
345 properly. This can make kmalloc/kfree-intensive workloads
346 much slower.
348 config DEBUG_OBJECTS_TIMERS
349 bool "Debug timer objects"
350 depends on DEBUG_OBJECTS
351 help
352 If you say Y here, additional code will be inserted into the
353 timer routines to track the life time of timer objects and
354 validate the timer operations.
356 config DEBUG_OBJECTS_WORK
357 bool "Debug work objects"
358 depends on DEBUG_OBJECTS
359 help
360 If you say Y here, additional code will be inserted into the
361 work queue routines to track the life time of work objects and
362 validate the work operations.
364 config DEBUG_OBJECTS_RCU_HEAD
365 bool "Debug RCU callbacks objects"
366 depends on DEBUG_OBJECTS
367 help
368 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
370 config DEBUG_OBJECTS_PERCPU_COUNTER
371 bool "Debug percpu counter objects"
372 depends on DEBUG_OBJECTS
373 help
374 If you say Y here, additional code will be inserted into the
375 percpu counter routines to track the life time of percpu counter
376 objects and validate the percpu counter operations.
378 config DEBUG_OBJECTS_ENABLE_DEFAULT
379 int "debug_objects bootup default value (0-1)"
380 range 0 1
381 default "1"
382 depends on DEBUG_OBJECTS
383 help
384 Debug objects boot parameter default value
386 config DEBUG_SLAB
387 bool "Debug slab memory allocations"
388 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
389 help
390 Say Y here to have the kernel do limited verification on memory
391 allocation as well as poisoning memory on free to catch use of freed
392 memory. This can make kmalloc/kfree-intensive workloads much slower.
394 config DEBUG_SLAB_LEAK
395 bool "Memory leak debugging"
396 depends on DEBUG_SLAB
398 config SLUB_DEBUG_ON
399 bool "SLUB debugging on by default"
400 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
401 default n
402 help
403 Boot with debugging on by default. SLUB boots by default with
404 the runtime debug capabilities switched off. Enabling this is
405 equivalent to specifying the "slub_debug" parameter on boot.
406 There is no support for more fine grained debug control like
407 possible with slub_debug=xxx. SLUB debugging may be switched
408 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
409 "slub_debug=-".
411 config SLUB_STATS
412 default n
413 bool "Enable SLUB performance statistics"
414 depends on SLUB && SYSFS
415 help
416 SLUB statistics are useful to debug SLUBs allocation behavior in
417 order find ways to optimize the allocator. This should never be
418 enabled for production use since keeping statistics slows down
419 the allocator by a few percentage points. The slabinfo command
420 supports the determination of the most active slabs to figure
421 out which slabs are relevant to a particular load.
422 Try running: slabinfo -DA
424 config HAVE_DEBUG_KMEMLEAK
425 bool
427 config DEBUG_KMEMLEAK
428 bool "Kernel memory leak detector"
429 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
430 select DEBUG_FS
431 select STACKTRACE if STACKTRACE_SUPPORT
432 select KALLSYMS
433 select CRC32
434 help
435 Say Y here if you want to enable the memory leak
436 detector. The memory allocation/freeing is traced in a way
437 similar to the Boehm's conservative garbage collector, the
438 difference being that the orphan objects are not freed but
439 only shown in /sys/kernel/debug/kmemleak. Enabling this
440 feature will introduce an overhead to memory
441 allocations. See Documentation/kmemleak.txt for more
442 details.
444 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
445 of finding leaks due to the slab objects poisoning.
447 In order to access the kmemleak file, debugfs needs to be
448 mounted (usually at /sys/kernel/debug).
450 config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
451 int "Maximum kmemleak early log entries"
452 depends on DEBUG_KMEMLEAK
453 range 200 40000
454 default 400
455 help
456 Kmemleak must track all the memory allocations to avoid
457 reporting false positives. Since memory may be allocated or
458 freed before kmemleak is initialised, an early log buffer is
459 used to store these actions. If kmemleak reports "early log
460 buffer exceeded", please increase this value.
462 config DEBUG_KMEMLEAK_TEST
463 tristate "Simple test for the kernel memory leak detector"
464 depends on DEBUG_KMEMLEAK && m
465 help
466 This option enables a module that explicitly leaks memory.
468 If unsure, say N.
470 config DEBUG_KMEMLEAK_DEFAULT_OFF
471 bool "Default kmemleak to off"
472 depends on DEBUG_KMEMLEAK
473 help
474 Say Y here to disable kmemleak by default. It can then be enabled
475 on the command line via kmemleak=on.
477 config DEBUG_STACK_USAGE
478 bool "Stack utilization instrumentation"
479 depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG
480 help
481 Enables the display of the minimum amount of free stack which each
482 task has ever had available in the sysrq-T and sysrq-P debug output.
484 This option will slow down process creation somewhat.
486 config DEBUG_VM
487 bool "Debug VM"
488 depends on DEBUG_KERNEL
489 help
490 Enable this to turn on extended checks in the virtual-memory system
491 that may impact performance.
493 If unsure, say N.
495 config DEBUG_VM_RB
496 bool "Debug VM red-black trees"
497 depends on DEBUG_VM
498 help
499 Enable this to turn on more extended checks in the virtual-memory
500 system that may impact performance.
502 If unsure, say N.
504 config DEBUG_VIRTUAL
505 bool "Debug VM translations"
506 depends on DEBUG_KERNEL && X86
507 help
508 Enable some costly sanity checks in virtual to page code. This can
509 catch mistakes with virt_to_page() and friends.
511 If unsure, say N.
513 config DEBUG_NOMMU_REGIONS
514 bool "Debug the global anon/private NOMMU mapping region tree"
515 depends on DEBUG_KERNEL && !MMU
516 help
517 This option causes the global tree of anonymous and private mapping
518 regions to be regularly checked for invalid topology.
520 config DEBUG_MEMORY_INIT
521 bool "Debug memory initialisation" if EXPERT
522 default !EXPERT
523 help
524 Enable this for additional checks during memory initialisation.
525 The sanity checks verify aspects of the VM such as the memory model
526 and other information provided by the architecture. Verbose
527 information will be printed at KERN_DEBUG loglevel depending
528 on the mminit_loglevel= command-line option.
530 If unsure, say Y
532 config MEMORY_NOTIFIER_ERROR_INJECT
533 tristate "Memory hotplug notifier error injection module"
534 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
535 help
536 This option provides the ability to inject artificial errors to
537 memory hotplug notifier chain callbacks. It is controlled through
538 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
540 If the notifier call chain should be failed with some events
541 notified, write the error code to "actions/<notifier event>/error".
543 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
545 # cd /sys/kernel/debug/notifier-error-inject/memory
546 # echo -12 > actions/MEM_GOING_OFFLINE/error
547 # echo offline > /sys/devices/system/memory/memoryXXX/state
548 bash: echo: write error: Cannot allocate memory
550 To compile this code as a module, choose M here: the module will
551 be called memory-notifier-error-inject.
553 If unsure, say N.
555 config DEBUG_PER_CPU_MAPS
556 bool "Debug access to per_cpu maps"
557 depends on DEBUG_KERNEL
558 depends on SMP
559 help
560 Say Y to verify that the per_cpu map being accessed has
561 been set up. This adds a fair amount of code to kernel memory
562 and decreases performance.
564 Say N if unsure.
566 config DEBUG_HIGHMEM
567 bool "Highmem debugging"
568 depends on DEBUG_KERNEL && HIGHMEM
569 help
570 This options enables addition error checking for high memory systems.
571 Disable for production systems.
573 config HAVE_DEBUG_STACKOVERFLOW
574 bool
576 config DEBUG_STACKOVERFLOW
577 bool "Check for stack overflows"
578 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
579 ---help---
580 Say Y here if you want to check for overflows of kernel, IRQ
581 and exception stacks (if your archicture uses them). This
582 option will show detailed messages if free stack space drops
583 below a certain limit.
585 These kinds of bugs usually occur when call-chains in the
586 kernel get too deep, especially when interrupts are
587 involved.
589 Use this in cases where you see apparently random memory
590 corruption, especially if it appears in 'struct thread_info'
592 If in doubt, say "N".
594 source "lib/Kconfig.kmemcheck"
596 endmenu # "Memory Debugging"
598 config DEBUG_SHIRQ
599 bool "Debug shared IRQ handlers"
600 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
601 help
602 Enable this to generate a spurious interrupt as soon as a shared
603 interrupt handler is registered, and just before one is deregistered.
604 Drivers ought to be able to handle interrupts coming in at those
605 points; some don't and need to be caught.
607 menu "Debug Lockups and Hangs"
609 config LOCKUP_DETECTOR
610 bool "Detect Hard and Soft Lockups"
611 depends on DEBUG_KERNEL && !S390
612 help
613 Say Y here to enable the kernel to act as a watchdog to detect
614 hard and soft lockups.
616 Softlockups are bugs that cause the kernel to loop in kernel
617 mode for more than 20 seconds, without giving other tasks a
618 chance to run. The current stack trace is displayed upon
619 detection and the system will stay locked up.
621 Hardlockups are bugs that cause the CPU to loop in kernel mode
622 for more than 10 seconds, without letting other interrupts have a
623 chance to run. The current stack trace is displayed upon detection
624 and the system will stay locked up.
626 The overhead should be minimal. A periodic hrtimer runs to
627 generate interrupts and kick the watchdog task every 4 seconds.
628 An NMI is generated every 10 seconds or so to check for hardlockups.
630 The frequency of hrtimer and NMI events and the soft and hard lockup
631 thresholds can be controlled through the sysctl watchdog_thresh.
633 config HARDLOCKUP_DETECTOR
634 def_bool y
635 depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG
636 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
638 config BOOTPARAM_HARDLOCKUP_PANIC
639 bool "Panic (Reboot) On Hard Lockups"
640 depends on HARDLOCKUP_DETECTOR
641 help
642 Say Y here to enable the kernel to panic on "hard lockups",
643 which are bugs that cause the kernel to loop in kernel
644 mode with interrupts disabled for more than 10 seconds (configurable
645 using the watchdog_thresh sysctl).
647 Say N if unsure.
649 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
650 int
651 depends on HARDLOCKUP_DETECTOR
652 range 0 1
653 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
654 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
656 config BOOTPARAM_SOFTLOCKUP_PANIC
657 bool "Panic (Reboot) On Soft Lockups"
658 depends on LOCKUP_DETECTOR
659 help
660 Say Y here to enable the kernel to panic on "soft lockups",
661 which are bugs that cause the kernel to loop in kernel
662 mode for more than 20 seconds (configurable using the watchdog_thresh
663 sysctl), without giving other tasks a chance to run.
665 The panic can be used in combination with panic_timeout,
666 to cause the system to reboot automatically after a
667 lockup has been detected. This feature is useful for
668 high-availability systems that have uptime guarantees and
669 where a lockup must be resolved ASAP.
671 Say N if unsure.
673 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
674 int
675 depends on LOCKUP_DETECTOR
676 range 0 1
677 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
678 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
680 config DETECT_HUNG_TASK
681 bool "Detect Hung Tasks"
682 depends on DEBUG_KERNEL
683 default LOCKUP_DETECTOR
684 help
685 Say Y here to enable the kernel to detect "hung tasks",
686 which are bugs that cause the task to be stuck in
687 uninterruptible "D" state indefinitiley.
689 When a hung task is detected, the kernel will print the
690 current stack trace (which you should report), but the
691 task will stay in uninterruptible state. If lockdep is
692 enabled then all held locks will also be reported. This
693 feature has negligible overhead.
695 config DEFAULT_HUNG_TASK_TIMEOUT
696 int "Default timeout for hung task detection (in seconds)"
697 depends on DETECT_HUNG_TASK
698 default 120
699 help
700 This option controls the default timeout (in seconds) used
701 to determine when a task has become non-responsive and should
702 be considered hung.
704 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
705 sysctl or by writing a value to
706 /proc/sys/kernel/hung_task_timeout_secs.
708 A timeout of 0 disables the check. The default is two minutes.
709 Keeping the default should be fine in most cases.
711 config BOOTPARAM_HUNG_TASK_PANIC
712 bool "Panic (Reboot) On Hung Tasks"
713 depends on DETECT_HUNG_TASK
714 help
715 Say Y here to enable the kernel to panic on "hung tasks",
716 which are bugs that cause the kernel to leave a task stuck
717 in uninterruptible "D" state.
719 The panic can be used in combination with panic_timeout,
720 to cause the system to reboot automatically after a
721 hung task has been detected. This feature is useful for
722 high-availability systems that have uptime guarantees and
723 where a hung tasks must be resolved ASAP.
725 Say N if unsure.
727 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
728 int
729 depends on DETECT_HUNG_TASK
730 range 0 1
731 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
732 default 1 if BOOTPARAM_HUNG_TASK_PANIC
734 endmenu # "Debug lockups and hangs"
736 config PANIC_ON_OOPS
737 bool "Panic on Oops"
738 help
739 Say Y here to enable the kernel to panic when it oopses. This
740 has the same effect as setting oops=panic on the kernel command
741 line.
743 This feature is useful to ensure that the kernel does not do
744 anything erroneous after an oops which could result in data
745 corruption or other issues.
747 Say N if unsure.
749 config PANIC_ON_OOPS_VALUE
750 int
751 range 0 1
752 default 0 if !PANIC_ON_OOPS
753 default 1 if PANIC_ON_OOPS
755 config SCHED_DEBUG
756 bool "Collect scheduler debugging info"
757 depends on DEBUG_KERNEL && PROC_FS
758 default y
759 help
760 If you say Y here, the /proc/sched_debug file will be provided
761 that can help debug the scheduler. The runtime overhead of this
762 option is minimal.
764 config SCHEDSTATS
765 bool "Collect scheduler statistics"
766 depends on DEBUG_KERNEL && PROC_FS
767 help
768 If you say Y here, additional code will be inserted into the
769 scheduler and related routines to collect statistics about
770 scheduler behavior and provide them in /proc/schedstat. These
771 stats may be useful for both tuning and debugging the scheduler
772 If you aren't debugging the scheduler or trying to tune a specific
773 application, you can say N to avoid the very slight overhead
774 this adds.
776 config TIMER_STATS
777 bool "Collect kernel timers statistics"
778 depends on DEBUG_KERNEL && PROC_FS
779 help
780 If you say Y here, additional code will be inserted into the
781 timer routines to collect statistics about kernel timers being
782 reprogrammed. The statistics can be read from /proc/timer_stats.
783 The statistics collection is started by writing 1 to /proc/timer_stats,
784 writing 0 stops it. This feature is useful to collect information
785 about timer usage patterns in kernel and userspace. This feature
786 is lightweight if enabled in the kernel config but not activated
787 (it defaults to deactivated on bootup and will only be activated
788 if some application like powertop activates it explicitly).
790 config DEBUG_PREEMPT
791 bool "Debug preemptible kernel"
792 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
793 default y
794 help
795 If you say Y here then the kernel will use a debug variant of the
796 commonly used smp_processor_id() function and will print warnings
797 if kernel code uses it in a preemption-unsafe way. Also, the kernel
798 will detect preemption count underflows.
800 menu "Lock Debugging (spinlocks, mutexes, etc...)"
802 config DEBUG_RT_MUTEXES
803 bool "RT Mutex debugging, deadlock detection"
804 depends on DEBUG_KERNEL && RT_MUTEXES
805 help
806 This allows rt mutex semantics violations and rt mutex related
807 deadlocks (lockups) to be detected and reported automatically.
809 config DEBUG_PI_LIST
810 bool
811 default y
812 depends on DEBUG_RT_MUTEXES
814 config RT_MUTEX_TESTER
815 bool "Built-in scriptable tester for rt-mutexes"
816 depends on DEBUG_KERNEL && RT_MUTEXES
817 help
818 This option enables a rt-mutex tester.
820 config DEBUG_SPINLOCK
821 bool "Spinlock and rw-lock debugging: basic checks"
822 depends on DEBUG_KERNEL
823 select UNINLINE_SPIN_UNLOCK
824 help
825 Say Y here and build SMP to catch missing spinlock initialization
826 and certain other kinds of spinlock errors commonly made. This is
827 best used in conjunction with the NMI watchdog so that spinlock
828 deadlocks are also debuggable.
830 config DEBUG_MUTEXES
831 bool "Mutex debugging: basic checks"
832 depends on DEBUG_KERNEL
833 help
834 This feature allows mutex semantics violations to be detected and
835 reported.
837 config DEBUG_WW_MUTEX_SLOWPATH
838 bool "Wait/wound mutex debugging: Slowpath testing"
839 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
840 select DEBUG_LOCK_ALLOC
841 select DEBUG_SPINLOCK
842 select DEBUG_MUTEXES
843 help
844 This feature enables slowpath testing for w/w mutex users by
845 injecting additional -EDEADLK wound/backoff cases. Together with
846 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
847 will test all possible w/w mutex interface abuse with the
848 exception of simply not acquiring all the required locks.
850 config DEBUG_LOCK_ALLOC
851 bool "Lock debugging: detect incorrect freeing of live locks"
852 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
853 select DEBUG_SPINLOCK
854 select DEBUG_MUTEXES
855 select LOCKDEP
856 help
857 This feature will check whether any held lock (spinlock, rwlock,
858 mutex or rwsem) is incorrectly freed by the kernel, via any of the
859 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
860 vfree(), etc.), whether a live lock is incorrectly reinitialized via
861 spin_lock_init()/mutex_init()/etc., or whether there is any lock
862 held during task exit.
864 config PROVE_LOCKING
865 bool "Lock debugging: prove locking correctness"
866 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
867 select LOCKDEP
868 select DEBUG_SPINLOCK
869 select DEBUG_MUTEXES
870 select DEBUG_LOCK_ALLOC
871 select TRACE_IRQFLAGS
872 default n
873 help
874 This feature enables the kernel to prove that all locking
875 that occurs in the kernel runtime is mathematically
876 correct: that under no circumstance could an arbitrary (and
877 not yet triggered) combination of observed locking
878 sequences (on an arbitrary number of CPUs, running an
879 arbitrary number of tasks and interrupt contexts) cause a
880 deadlock.
882 In short, this feature enables the kernel to report locking
883 related deadlocks before they actually occur.
885 The proof does not depend on how hard and complex a
886 deadlock scenario would be to trigger: how many
887 participant CPUs, tasks and irq-contexts would be needed
888 for it to trigger. The proof also does not depend on
889 timing: if a race and a resulting deadlock is possible
890 theoretically (no matter how unlikely the race scenario
891 is), it will be proven so and will immediately be
892 reported by the kernel (once the event is observed that
893 makes the deadlock theoretically possible).
895 If a deadlock is impossible (i.e. the locking rules, as
896 observed by the kernel, are mathematically correct), the
897 kernel reports nothing.
899 NOTE: this feature can also be enabled for rwlocks, mutexes
900 and rwsems - in which case all dependencies between these
901 different locking variants are observed and mapped too, and
902 the proof of observed correctness is also maintained for an
903 arbitrary combination of these separate locking variants.
905 For more details, see Documentation/lockdep-design.txt.
907 config LOCKDEP
908 bool
909 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
910 select STACKTRACE
911 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
912 select KALLSYMS
913 select KALLSYMS_ALL
915 config LOCK_STAT
916 bool "Lock usage statistics"
917 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
918 select LOCKDEP
919 select DEBUG_SPINLOCK
920 select DEBUG_MUTEXES
921 select DEBUG_LOCK_ALLOC
922 default n
923 help
924 This feature enables tracking lock contention points
926 For more details, see Documentation/lockstat.txt
928 This also enables lock events required by "perf lock",
929 subcommand of perf.
930 If you want to use "perf lock", you also need to turn on
931 CONFIG_EVENT_TRACING.
933 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
934 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
936 config DEBUG_LOCKDEP
937 bool "Lock dependency engine debugging"
938 depends on DEBUG_KERNEL && LOCKDEP
939 help
940 If you say Y here, the lock dependency engine will do
941 additional runtime checks to debug itself, at the price
942 of more runtime overhead.
944 config DEBUG_ATOMIC_SLEEP
945 bool "Sleep inside atomic section checking"
946 select PREEMPT_COUNT
947 depends on DEBUG_KERNEL
948 help
949 If you say Y here, various routines which may sleep will become very
950 noisy if they are called inside atomic sections: when a spinlock is
951 held, inside an rcu read side critical section, inside preempt disabled
952 sections, inside an interrupt, etc...
954 config DEBUG_LOCKING_API_SELFTESTS
955 bool "Locking API boot-time self-tests"
956 depends on DEBUG_KERNEL
957 help
958 Say Y here if you want the kernel to run a short self-test during
959 bootup. The self-test checks whether common types of locking bugs
960 are detected by debugging mechanisms or not. (if you disable
961 lock debugging then those bugs wont be detected of course.)
962 The following locking APIs are covered: spinlocks, rwlocks,
963 mutexes and rwsems.
965 endmenu # lock debugging
967 config TRACE_IRQFLAGS
968 bool
969 help
970 Enables hooks to interrupt enabling and disabling for
971 either tracing or lock debugging.
973 config STACKTRACE
974 bool
975 depends on STACKTRACE_SUPPORT
977 config DEBUG_KOBJECT
978 bool "kobject debugging"
979 depends on DEBUG_KERNEL
980 help
981 If you say Y here, some extra kobject debugging messages will be sent
982 to the syslog.
984 config HAVE_DEBUG_BUGVERBOSE
985 bool
987 config DEBUG_BUGVERBOSE
988 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
989 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
990 default y
991 help
992 Say Y here to make BUG() panics output the file name and line number
993 of the BUG call as well as the EIP and oops trace. This aids
994 debugging but costs about 70-100K of memory.
996 config DEBUG_WRITECOUNT
997 bool "Debug filesystem writers count"
998 depends on DEBUG_KERNEL
999 help
1000 Enable this to catch wrong use of the writers count in struct
1001 vfsmount. This will increase the size of each file struct by
1002 32 bits.
1004 If unsure, say N.
1006 config DEBUG_LIST
1007 bool "Debug linked list manipulation"
1008 depends on DEBUG_KERNEL
1009 help
1010 Enable this to turn on extended checks in the linked-list
1011 walking routines.
1013 If unsure, say N.
1015 config DEBUG_SG
1016 bool "Debug SG table operations"
1017 depends on DEBUG_KERNEL
1018 help
1019 Enable this to turn on checks on scatter-gather tables. This can
1020 help find problems with drivers that do not properly initialize
1021 their sg tables.
1023 If unsure, say N.
1025 config DEBUG_NOTIFIERS
1026 bool "Debug notifier call chains"
1027 depends on DEBUG_KERNEL
1028 help
1029 Enable this to turn on sanity checking for notifier call chains.
1030 This is most useful for kernel developers to make sure that
1031 modules properly unregister themselves from notifier chains.
1032 This is a relatively cheap check but if you care about maximum
1033 performance, say N.
1035 config DEBUG_CREDENTIALS
1036 bool "Debug credential management"
1037 depends on DEBUG_KERNEL
1038 help
1039 Enable this to turn on some debug checking for credential
1040 management. The additional code keeps track of the number of
1041 pointers from task_structs to any given cred struct, and checks to
1042 see that this number never exceeds the usage count of the cred
1043 struct.
1045 Furthermore, if SELinux is enabled, this also checks that the
1046 security pointer in the cred struct is never seen to be invalid.
1048 If unsure, say N.
1050 menu "RCU Debugging"
1052 config PROVE_RCU
1053 bool "RCU debugging: prove RCU correctness"
1054 depends on PROVE_LOCKING
1055 default n
1056 help
1057 This feature enables lockdep extensions that check for correct
1058 use of RCU APIs. This is currently under development. Say Y
1059 if you want to debug RCU usage or help work on the PROVE_RCU
1060 feature.
1062 Say N if you are unsure.
1064 config PROVE_RCU_REPEATEDLY
1065 bool "RCU debugging: don't disable PROVE_RCU on first splat"
1066 depends on PROVE_RCU
1067 default n
1068 help
1069 By itself, PROVE_RCU will disable checking upon issuing the
1070 first warning (or "splat"). This feature prevents such
1071 disabling, allowing multiple RCU-lockdep warnings to be printed
1072 on a single reboot.
1074 Say Y to allow multiple RCU-lockdep warnings per boot.
1076 Say N if you are unsure.
1078 config PROVE_RCU_DELAY
1079 bool "RCU debugging: preemptible RCU race provocation"
1080 depends on DEBUG_KERNEL && PREEMPT_RCU
1081 default n
1082 help
1083 There is a class of races that involve an unlikely preemption
1084 of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
1085 been set to INT_MIN. This feature inserts a delay at that
1086 point to increase the probability of these races.
1088 Say Y to increase probability of preemption of __rcu_read_unlock().
1090 Say N if you are unsure.
1092 config SPARSE_RCU_POINTER
1093 bool "RCU debugging: sparse-based checks for pointer usage"
1094 default n
1095 help
1096 This feature enables the __rcu sparse annotation for
1097 RCU-protected pointers. This annotation will cause sparse
1098 to flag any non-RCU used of annotated pointers. This can be
1099 helpful when debugging RCU usage. Please note that this feature
1100 is not intended to enforce code cleanliness; it is instead merely
1101 a debugging aid.
1103 Say Y to make sparse flag questionable use of RCU-protected pointers
1105 Say N if you are unsure.
1107 config RCU_TORTURE_TEST
1108 tristate "torture tests for RCU"
1109 depends on DEBUG_KERNEL
1110 default n
1111 help
1112 This option provides a kernel module that runs torture tests
1113 on the RCU infrastructure. The kernel module may be built
1114 after the fact on the running kernel to be tested, if desired.
1116 Say Y here if you want RCU torture tests to be built into
1117 the kernel.
1118 Say M if you want the RCU torture tests to build as a module.
1119 Say N if you are unsure.
1121 config RCU_TORTURE_TEST_RUNNABLE
1122 bool "torture tests for RCU runnable by default"
1123 depends on RCU_TORTURE_TEST = y
1124 default n
1125 help
1126 This option provides a way to build the RCU torture tests
1127 directly into the kernel without them starting up at boot
1128 time. You can use /proc/sys/kernel/rcutorture_runnable
1129 to manually override this setting. This /proc file is
1130 available only when the RCU torture tests have been built
1131 into the kernel.
1133 Say Y here if you want the RCU torture tests to start during
1134 boot (you probably don't).
1135 Say N here if you want the RCU torture tests to start only
1136 after being manually enabled via /proc.
1138 config RCU_CPU_STALL_TIMEOUT
1139 int "RCU CPU stall timeout in seconds"
1140 depends on RCU_STALL_COMMON
1141 range 3 300
1142 default 21
1143 help
1144 If a given RCU grace period extends more than the specified
1145 number of seconds, a CPU stall warning is printed. If the
1146 RCU grace period persists, additional CPU stall warnings are
1147 printed at more widely spaced intervals.
1149 config RCU_CPU_STALL_VERBOSE
1150 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
1151 depends on TREE_PREEMPT_RCU
1152 default y
1153 help
1154 This option causes RCU to printk detailed per-task information
1155 for any tasks that are stalling the current RCU grace period.
1157 Say N if you are unsure.
1159 Say Y if you want to enable such checks.
1161 config RCU_CPU_STALL_INFO
1162 bool "Print additional diagnostics on RCU CPU stall"
1163 depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
1164 default n
1165 help
1166 For each stalled CPU that is aware of the current RCU grace
1167 period, print out additional per-CPU diagnostic information
1168 regarding scheduling-clock ticks, idle state, and,
1169 for RCU_FAST_NO_HZ kernels, idle-entry state.
1171 Say N if you are unsure.
1173 Say Y if you want to enable such diagnostics.
1175 config RCU_TRACE
1176 bool "Enable tracing for RCU"
1177 depends on DEBUG_KERNEL
1178 select TRACE_CLOCK
1179 help
1180 This option provides tracing in RCU which presents stats
1181 in debugfs for debugging RCU implementation.
1183 Say Y here if you want to enable RCU tracing
1184 Say N if you are unsure.
1186 endmenu # "RCU Debugging"
1188 config DEBUG_BLOCK_EXT_DEVT
1189 bool "Force extended block device numbers and spread them"
1190 depends on DEBUG_KERNEL
1191 depends on BLOCK
1192 default n
1193 help
1194 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1195 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1196 YOU ARE DOING. Distros, please enable this and fix whatever
1197 is broken.
1199 Conventionally, block device numbers are allocated from
1200 predetermined contiguous area. However, extended block area
1201 may introduce non-contiguous block device numbers. This
1202 option forces most block device numbers to be allocated from
1203 the extended space and spreads them to discover kernel or
1204 userland code paths which assume predetermined contiguous
1205 device number allocation.
1207 Note that turning on this debug option shuffles all the
1208 device numbers for all IDE and SCSI devices including libata
1209 ones, so root partition specified using device number
1210 directly (via rdev or root=MAJ:MIN) won't work anymore.
1211 Textual device names (root=/dev/sdXn) will continue to work.
1213 Say N if you are unsure.
1215 config NOTIFIER_ERROR_INJECTION
1216 tristate "Notifier error injection"
1217 depends on DEBUG_KERNEL
1218 select DEBUG_FS
1219 help
1220 This option provides the ability to inject artificial errors to
1221 specified notifier chain callbacks. It is useful to test the error
1222 handling of notifier call chain failures.
1224 Say N if unsure.
1226 config CPU_NOTIFIER_ERROR_INJECT
1227 tristate "CPU notifier error injection module"
1228 depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
1229 help
1230 This option provides a kernel module that can be used to test
1231 the error handling of the cpu notifiers by injecting artificial
1232 errors to CPU notifier chain callbacks. It is controlled through
1233 debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu
1235 If the notifier call chain should be failed with some events
1236 notified, write the error code to "actions/<notifier event>/error".
1238 Example: Inject CPU offline error (-1 == -EPERM)
1240 # cd /sys/kernel/debug/notifier-error-inject/cpu
1241 # echo -1 > actions/CPU_DOWN_PREPARE/error
1242 # echo 0 > /sys/devices/system/cpu/cpu1/online
1243 bash: echo: write error: Operation not permitted
1245 To compile this code as a module, choose M here: the module will
1246 be called cpu-notifier-error-inject.
1248 If unsure, say N.
1250 config PM_NOTIFIER_ERROR_INJECT
1251 tristate "PM notifier error injection module"
1252 depends on PM && NOTIFIER_ERROR_INJECTION
1253 default m if PM_DEBUG
1254 help
1255 This option provides the ability to inject artificial errors to
1256 PM notifier chain callbacks. It is controlled through debugfs
1257 interface /sys/kernel/debug/notifier-error-inject/pm
1259 If the notifier call chain should be failed with some events
1260 notified, write the error code to "actions/<notifier event>/error".
1262 Example: Inject PM suspend error (-12 = -ENOMEM)
1264 # cd /sys/kernel/debug/notifier-error-inject/pm/
1265 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1266 # echo mem > /sys/power/state
1267 bash: echo: write error: Cannot allocate memory
1269 To compile this code as a module, choose M here: the module will
1270 be called pm-notifier-error-inject.
1272 If unsure, say N.
1274 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1275 tristate "OF reconfig notifier error injection module"
1276 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1277 help
1278 This option provides the ability to inject artificial errors to
1279 OF reconfig notifier chain callbacks. It is controlled
1280 through debugfs interface under
1281 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1283 If the notifier call chain should be failed with some events
1284 notified, write the error code to "actions/<notifier event>/error".
1286 To compile this code as a module, choose M here: the module will
1287 be called of-reconfig-notifier-error-inject.
1289 If unsure, say N.
1291 config FAULT_INJECTION
1292 bool "Fault-injection framework"
1293 depends on DEBUG_KERNEL
1294 help
1295 Provide fault-injection framework.
1296 For more details, see Documentation/fault-injection/.
1298 config FAILSLAB
1299 bool "Fault-injection capability for kmalloc"
1300 depends on FAULT_INJECTION
1301 depends on SLAB || SLUB
1302 help
1303 Provide fault-injection capability for kmalloc.
1305 config FAIL_PAGE_ALLOC
1306 bool "Fault-injection capabilitiy for alloc_pages()"
1307 depends on FAULT_INJECTION
1308 help
1309 Provide fault-injection capability for alloc_pages().
1311 config FAIL_MAKE_REQUEST
1312 bool "Fault-injection capability for disk IO"
1313 depends on FAULT_INJECTION && BLOCK
1314 help
1315 Provide fault-injection capability for disk IO.
1317 config FAIL_IO_TIMEOUT
1318 bool "Fault-injection capability for faking disk interrupts"
1319 depends on FAULT_INJECTION && BLOCK
1320 help
1321 Provide fault-injection capability on end IO handling. This
1322 will make the block layer "forget" an interrupt as configured,
1323 thus exercising the error handling.
1325 Only works with drivers that use the generic timeout handling,
1326 for others it wont do anything.
1328 config FAIL_MMC_REQUEST
1329 bool "Fault-injection capability for MMC IO"
1330 select DEBUG_FS
1331 depends on FAULT_INJECTION && MMC
1332 help
1333 Provide fault-injection capability for MMC IO.
1334 This will make the mmc core return data errors. This is
1335 useful to test the error handling in the mmc block device
1336 and to test how the mmc host driver handles retries from
1337 the block device.
1339 config FAULT_INJECTION_DEBUG_FS
1340 bool "Debugfs entries for fault-injection capabilities"
1341 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1342 help
1343 Enable configuration of fault-injection capabilities via debugfs.
1345 config FAULT_INJECTION_STACKTRACE_FILTER
1346 bool "stacktrace filter for fault-injection capabilities"
1347 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1348 depends on !X86_64
1349 select STACKTRACE
1350 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
1351 help
1352 Provide stacktrace filter for fault-injection capabilities
1354 config LATENCYTOP
1355 bool "Latency measuring infrastructure"
1356 depends on HAVE_LATENCYTOP_SUPPORT
1357 depends on DEBUG_KERNEL
1358 depends on STACKTRACE_SUPPORT
1359 depends on PROC_FS
1360 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
1361 select KALLSYMS
1362 select KALLSYMS_ALL
1363 select STACKTRACE
1364 select SCHEDSTATS
1365 select SCHED_DEBUG
1366 help
1367 Enable this option if you want to use the LatencyTOP tool
1368 to find out which userspace is blocking on what kernel operations.
1370 config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1371 bool
1373 config DEBUG_STRICT_USER_COPY_CHECKS
1374 bool "Strict user copy size checks"
1375 depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1376 depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING
1377 help
1378 Enabling this option turns a certain set of sanity checks for user
1379 copy operations into compile time failures.
1381 The copy_from_user() etc checks are there to help test if there
1382 are sufficient security checks on the length argument of
1383 the copy operation, by having gcc prove that the argument is
1384 within bounds.
1386 If unsure, say N.
1388 source kernel/trace/Kconfig
1390 menu "Runtime Testing"
1392 config LKDTM
1393 tristate "Linux Kernel Dump Test Tool Module"
1394 depends on DEBUG_FS
1395 depends on BLOCK
1396 default n
1397 help
1398 This module enables testing of the different dumping mechanisms by
1399 inducing system failures at predefined crash points.
1400 If you don't need it: say N
1401 Choose M here to compile this code as a module. The module will be
1402 called lkdtm.
1404 Documentation on how to use the module can be found in
1405 Documentation/fault-injection/provoke-crashes.txt
1407 config TEST_LIST_SORT
1408 bool "Linked list sorting test"
1409 depends on DEBUG_KERNEL
1410 help
1411 Enable this to turn on 'list_sort()' function test. This test is
1412 executed only once during system boot, so affects only boot time.
1414 If unsure, say N.
1416 config KPROBES_SANITY_TEST
1417 bool "Kprobes sanity tests"
1418 depends on DEBUG_KERNEL
1419 depends on KPROBES
1420 default n
1421 help
1422 This option provides for testing basic kprobes functionality on
1423 boot. A sample kprobe, jprobe and kretprobe are inserted and
1424 verified for functionality.
1426 Say N if you are unsure.
1428 config BACKTRACE_SELF_TEST
1429 tristate "Self test for the backtrace code"
1430 depends on DEBUG_KERNEL
1431 default n
1432 help
1433 This option provides a kernel module that can be used to test
1434 the kernel stack backtrace code. This option is not useful
1435 for distributions or general kernels, but only for kernel
1436 developers working on architecture code.
1438 Note that if you want to also test saved backtraces, you will
1439 have to enable STACKTRACE as well.
1441 Say N if you are unsure.
1443 config RBTREE_TEST
1444 tristate "Red-Black tree test"
1445 depends on m && DEBUG_KERNEL
1446 help
1447 A benchmark measuring the performance of the rbtree library.
1448 Also includes rbtree invariant checks.
1450 config INTERVAL_TREE_TEST
1451 tristate "Interval tree test"
1452 depends on m && DEBUG_KERNEL
1453 help
1454 A benchmark measuring the performance of the interval tree library
1456 config ATOMIC64_SELFTEST
1457 bool "Perform an atomic64_t self-test at boot"
1458 help
1459 Enable this option to test the atomic64_t functions at boot.
1461 If unsure, say N.
1463 config ASYNC_RAID6_TEST
1464 tristate "Self test for hardware accelerated raid6 recovery"
1465 depends on ASYNC_RAID6_RECOV
1466 select ASYNC_MEMCPY
1467 ---help---
1468 This is a one-shot self test that permutes through the
1469 recovery of all the possible two disk failure scenarios for a
1470 N-disk array. Recovery is performed with the asynchronous
1471 raid6 recovery routines, and will optionally use an offload
1472 engine if one is available.
1474 If unsure, say N.
1476 config TEST_STRING_HELPERS
1477 tristate "Test functions located in the string_helpers module at runtime"
1479 config TEST_KSTRTOX
1480 tristate "Test kstrto*() family of functions at runtime"
1482 endmenu # runtime tests
1484 config PROVIDE_OHCI1394_DMA_INIT
1485 bool "Remote debugging over FireWire early on boot"
1486 depends on PCI && X86
1487 help
1488 If you want to debug problems which hang or crash the kernel early
1489 on boot and the crashing machine has a FireWire port, you can use
1490 this feature to remotely access the memory of the crashed machine
1491 over FireWire. This employs remote DMA as part of the OHCI1394
1492 specification which is now the standard for FireWire controllers.
1494 With remote DMA, you can monitor the printk buffer remotely using
1495 firescope and access all memory below 4GB using fireproxy from gdb.
1496 Even controlling a kernel debugger is possible using remote DMA.
1498 Usage:
1500 If ohci1394_dma=early is used as boot parameter, it will initialize
1501 all OHCI1394 controllers which are found in the PCI config space.
1503 As all changes to the FireWire bus such as enabling and disabling
1504 devices cause a bus reset and thereby disable remote DMA for all
1505 devices, be sure to have the cable plugged and FireWire enabled on
1506 the debugging host before booting the debug target for debugging.
1508 This code (~1k) is freed after boot. By then, the firewire stack
1509 in charge of the OHCI-1394 controllers should be used instead.
1511 See Documentation/debugging-via-ohci1394.txt for more information.
1513 config FIREWIRE_OHCI_REMOTE_DMA
1514 bool "Remote debugging over FireWire with firewire-ohci"
1515 depends on FIREWIRE_OHCI
1516 help
1517 This option lets you use the FireWire bus for remote debugging
1518 with help of the firewire-ohci driver. It enables unfiltered
1519 remote DMA in firewire-ohci.
1520 See Documentation/debugging-via-ohci1394.txt for more information.
1522 If unsure, say N.
1524 config BUILD_DOCSRC
1525 bool "Build targets in Documentation/ tree"
1526 depends on HEADERS_CHECK
1527 help
1528 This option attempts to build objects from the source files in the
1529 kernel Documentation/ tree.
1531 Say N if you are unsure.
1533 config DMA_API_DEBUG
1534 bool "Enable debugging of DMA-API usage"
1535 depends on HAVE_DMA_API_DEBUG
1536 help
1537 Enable this option to debug the use of the DMA API by device drivers.
1538 With this option you will be able to detect common bugs in device
1539 drivers like double-freeing of DMA mappings or freeing mappings that
1540 were never allocated.
1541 This option causes a performance degredation. Use only if you want
1542 to debug device drivers. If unsure, say N.
1544 source "samples/Kconfig"
1546 source "lib/Kconfig.kgdb"