Version:  2.0.40 2.2.26 2.4.37 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15

Linux/lib/Kconfig.debug

  1 menu "printk and dmesg options"
  2 
  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.
 10 
 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.
 14 
 15           The behavior is also controlled by the kernel command line
 16           parameter printk.time=1. See Documentation/kernel-parameters.txt
 17 
 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.
 24 
 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.
 28 
 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".
 37 
 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.
 46 
 47 config DYNAMIC_DEBUG
 48         bool "Enable dynamic printk() support"
 49         default n
 50         depends on PRINTK
 51         depends on DEBUG_FS
 52         help
 53 
 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%.
 60 
 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.
 65 
 66           Usage:
 67 
 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:
 74 
 75                 filename:lineno [module]function flags format
 76 
 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
 83 
 84           From a live system:
 85 
 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"
 91 
 92           Example usage:
 93 
 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
 97 
 98                 // enable all the messages in file svcsock.c
 99                 nullarbor:~ # echo -n 'file svcsock.c +p' >
100                                                 <debugfs>/dynamic_debug/control
101 
102                 // enable all the messages in the NFS server module
103                 nullarbor:~ # echo -n 'module nfsd +p' >
104                                                 <debugfs>/dynamic_debug/control
105 
106                 // enable all 12 messages in the function svc_process()
107                 nullarbor:~ # echo -n 'func svc_process +p' >
108                                                 <debugfs>/dynamic_debug/control
109 
110                 // disable all 12 messages in the function svc_process()
111                 nullarbor:~ # echo -n 'func svc_process -p' >
112                                                 <debugfs>/dynamic_debug/control
113 
114           See Documentation/dynamic-debug-howto.txt for additional information.
115 
116 endmenu # "printk and dmesg options"
117 
118 menu "Compile-time checks and compiler options"
119 
120 config DEBUG_INFO
121         bool "Compile the kernel with debug info"
122         depends on DEBUG_KERNEL && !COMPILE_TEST
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.
130 
131           If unsure, say N.
132 
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.
145 
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.
153 
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.
161 
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
172 
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.
180 
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.
189 
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.
205 
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.
212 
213           For detailed documentation on the debugfs API, see
214           Documentation/DocBook/filesystems.
215 
216           If unsure, say N.
217 
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.
226 
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.
231 
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.
262 
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
271 
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)
283 
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.
292 
293           1. percpu symbols must be unique whether static or not
294           2. percpu variables can't be defined inside a function
295 
296           To ensure that generic code follows the above rules, this
297           option forces all percpu variables to be defined as weak.
298 
299 endmenu # "Compiler options"
300 
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.
314 
315 config MAGIC_SYSRQ_DEFAULT_ENABLE
316         hex "Enable magic SysRq key functions by default"
317         depends on MAGIC_SYSRQ
318         default 0x1
319         help
320           Specifies which SysRq key functions are enabled by default.
321           This may be set to 1 or 0 to enable or disable them all, or
322           to a bitmask as described in Documentation/sysrq.txt.
323 
324 config DEBUG_KERNEL
325         bool "Kernel debugging"
326         help
327           Say Y here if you are developing drivers or trying to debug and
328           identify kernel problems.
329 
330 menu "Memory Debugging"
331 
332 source mm/Kconfig.debug
333 
334 config DEBUG_OBJECTS
335         bool "Debug object operations"
336         depends on DEBUG_KERNEL
337         help
338           If you say Y here, additional code will be inserted into the
339           kernel to track the life time of various objects and validate
340           the operations on those objects.
341 
342 config DEBUG_OBJECTS_SELFTEST
343         bool "Debug objects selftest"
344         depends on DEBUG_OBJECTS
345         help
346           This enables the selftest of the object debug code.
347 
348 config DEBUG_OBJECTS_FREE
349         bool "Debug objects in freed memory"
350         depends on DEBUG_OBJECTS
351         help
352           This enables checks whether a k/v free operation frees an area
353           which contains an object which has not been deactivated
354           properly. This can make kmalloc/kfree-intensive workloads
355           much slower.
356 
357 config DEBUG_OBJECTS_TIMERS
358         bool "Debug timer objects"
359         depends on DEBUG_OBJECTS
360         help
361           If you say Y here, additional code will be inserted into the
362           timer routines to track the life time of timer objects and
363           validate the timer operations.
364 
365 config DEBUG_OBJECTS_WORK
366         bool "Debug work objects"
367         depends on DEBUG_OBJECTS
368         help
369           If you say Y here, additional code will be inserted into the
370           work queue routines to track the life time of work objects and
371           validate the work operations.
372 
373 config DEBUG_OBJECTS_RCU_HEAD
374         bool "Debug RCU callbacks objects"
375         depends on DEBUG_OBJECTS
376         help
377           Enable this to turn on debugging of RCU list heads (call_rcu() usage).
378 
379 config DEBUG_OBJECTS_PERCPU_COUNTER
380         bool "Debug percpu counter objects"
381         depends on DEBUG_OBJECTS
382         help
383           If you say Y here, additional code will be inserted into the
384           percpu counter routines to track the life time of percpu counter
385           objects and validate the percpu counter operations.
386 
387 config DEBUG_OBJECTS_ENABLE_DEFAULT
388         int "debug_objects bootup default value (0-1)"
389         range 0 1
390         default "1"
391         depends on DEBUG_OBJECTS
392         help
393           Debug objects boot parameter default value
394 
395 config DEBUG_SLAB
396         bool "Debug slab memory allocations"
397         depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
398         help
399           Say Y here to have the kernel do limited verification on memory
400           allocation as well as poisoning memory on free to catch use of freed
401           memory. This can make kmalloc/kfree-intensive workloads much slower.
402 
403 config DEBUG_SLAB_LEAK
404         bool "Memory leak debugging"
405         depends on DEBUG_SLAB
406 
407 config SLUB_DEBUG_ON
408         bool "SLUB debugging on by default"
409         depends on SLUB && SLUB_DEBUG && !KMEMCHECK
410         default n
411         help
412           Boot with debugging on by default. SLUB boots by default with
413           the runtime debug capabilities switched off. Enabling this is
414           equivalent to specifying the "slub_debug" parameter on boot.
415           There is no support for more fine grained debug control like
416           possible with slub_debug=xxx. SLUB debugging may be switched
417           off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
418           "slub_debug=-".
419 
420 config SLUB_STATS
421         default n
422         bool "Enable SLUB performance statistics"
423         depends on SLUB && SYSFS
424         help
425           SLUB statistics are useful to debug SLUBs allocation behavior in
426           order find ways to optimize the allocator. This should never be
427           enabled for production use since keeping statistics slows down
428           the allocator by a few percentage points. The slabinfo command
429           supports the determination of the most active slabs to figure
430           out which slabs are relevant to a particular load.
431           Try running: slabinfo -DA
432 
433 config HAVE_DEBUG_KMEMLEAK
434         bool
435 
436 config DEBUG_KMEMLEAK
437         bool "Kernel memory leak detector"
438         depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
439         select DEBUG_FS
440         select STACKTRACE if STACKTRACE_SUPPORT
441         select KALLSYMS
442         select CRC32
443         help
444           Say Y here if you want to enable the memory leak
445           detector. The memory allocation/freeing is traced in a way
446           similar to the Boehm's conservative garbage collector, the
447           difference being that the orphan objects are not freed but
448           only shown in /sys/kernel/debug/kmemleak. Enabling this
449           feature will introduce an overhead to memory
450           allocations. See Documentation/kmemleak.txt for more
451           details.
452 
453           Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
454           of finding leaks due to the slab objects poisoning.
455 
456           In order to access the kmemleak file, debugfs needs to be
457           mounted (usually at /sys/kernel/debug).
458 
459 config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
460         int "Maximum kmemleak early log entries"
461         depends on DEBUG_KMEMLEAK
462         range 200 40000
463         default 400
464         help
465           Kmemleak must track all the memory allocations to avoid
466           reporting false positives. Since memory may be allocated or
467           freed before kmemleak is initialised, an early log buffer is
468           used to store these actions. If kmemleak reports "early log
469           buffer exceeded", please increase this value.
470 
471 config DEBUG_KMEMLEAK_TEST
472         tristate "Simple test for the kernel memory leak detector"
473         depends on DEBUG_KMEMLEAK && m
474         help
475           This option enables a module that explicitly leaks memory.
476 
477           If unsure, say N.
478 
479 config DEBUG_KMEMLEAK_DEFAULT_OFF
480         bool "Default kmemleak to off"
481         depends on DEBUG_KMEMLEAK
482         help
483           Say Y here to disable kmemleak by default. It can then be enabled
484           on the command line via kmemleak=on.
485 
486 config DEBUG_STACK_USAGE
487         bool "Stack utilization instrumentation"
488         depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG
489         help
490           Enables the display of the minimum amount of free stack which each
491           task has ever had available in the sysrq-T and sysrq-P debug output.
492 
493           This option will slow down process creation somewhat.
494 
495 config DEBUG_VM
496         bool "Debug VM"
497         depends on DEBUG_KERNEL
498         help
499           Enable this to turn on extended checks in the virtual-memory system
500           that may impact performance.
501 
502           If unsure, say N.
503 
504 config DEBUG_VM_RB
505         bool "Debug VM red-black trees"
506         depends on DEBUG_VM
507         help
508           Enable VM red-black tree debugging information and extra validations.
509 
510           If unsure, say N.
511 
512 config DEBUG_VIRTUAL
513         bool "Debug VM translations"
514         depends on DEBUG_KERNEL && X86
515         help
516           Enable some costly sanity checks in virtual to page code. This can
517           catch mistakes with virt_to_page() and friends.
518 
519           If unsure, say N.
520 
521 config DEBUG_NOMMU_REGIONS
522         bool "Debug the global anon/private NOMMU mapping region tree"
523         depends on DEBUG_KERNEL && !MMU
524         help
525           This option causes the global tree of anonymous and private mapping
526           regions to be regularly checked for invalid topology.
527 
528 config DEBUG_MEMORY_INIT
529         bool "Debug memory initialisation" if EXPERT
530         default !EXPERT
531         help
532           Enable this for additional checks during memory initialisation.
533           The sanity checks verify aspects of the VM such as the memory model
534           and other information provided by the architecture. Verbose
535           information will be printed at KERN_DEBUG loglevel depending
536           on the mminit_loglevel= command-line option.
537 
538           If unsure, say Y
539 
540 config MEMORY_NOTIFIER_ERROR_INJECT
541         tristate "Memory hotplug notifier error injection module"
542         depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
543         help
544           This option provides the ability to inject artificial errors to
545           memory hotplug notifier chain callbacks.  It is controlled through
546           debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
547 
548           If the notifier call chain should be failed with some events
549           notified, write the error code to "actions/<notifier event>/error".
550 
551           Example: Inject memory hotplug offline error (-12 == -ENOMEM)
552 
553           # cd /sys/kernel/debug/notifier-error-inject/memory
554           # echo -12 > actions/MEM_GOING_OFFLINE/error
555           # echo offline > /sys/devices/system/memory/memoryXXX/state
556           bash: echo: write error: Cannot allocate memory
557 
558           To compile this code as a module, choose M here: the module will
559           be called memory-notifier-error-inject.
560 
561           If unsure, say N.
562 
563 config DEBUG_PER_CPU_MAPS
564         bool "Debug access to per_cpu maps"
565         depends on DEBUG_KERNEL
566         depends on SMP
567         help
568           Say Y to verify that the per_cpu map being accessed has
569           been set up. This adds a fair amount of code to kernel memory
570           and decreases performance.
571 
572           Say N if unsure.
573 
574 config DEBUG_HIGHMEM
575         bool "Highmem debugging"
576         depends on DEBUG_KERNEL && HIGHMEM
577         help
578           This options enables addition error checking for high memory systems.
579           Disable for production systems.
580 
581 config HAVE_DEBUG_STACKOVERFLOW
582         bool
583 
584 config DEBUG_STACKOVERFLOW
585         bool "Check for stack overflows"
586         depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
587         ---help---
588           Say Y here if you want to check for overflows of kernel, IRQ
589           and exception stacks (if your archicture uses them). This
590           option will show detailed messages if free stack space drops
591           below a certain limit.
592 
593           These kinds of bugs usually occur when call-chains in the
594           kernel get too deep, especially when interrupts are
595           involved.
596 
597           Use this in cases where you see apparently random memory
598           corruption, especially if it appears in 'struct thread_info'
599 
600           If in doubt, say "N".
601 
602 source "lib/Kconfig.kmemcheck"
603 
604 endmenu # "Memory Debugging"
605 
606 config DEBUG_SHIRQ
607         bool "Debug shared IRQ handlers"
608         depends on DEBUG_KERNEL
609         help
610           Enable this to generate a spurious interrupt as soon as a shared
611           interrupt handler is registered, and just before one is deregistered.
612           Drivers ought to be able to handle interrupts coming in at those
613           points; some don't and need to be caught.
614 
615 menu "Debug Lockups and Hangs"
616 
617 config LOCKUP_DETECTOR
618         bool "Detect Hard and Soft Lockups"
619         depends on DEBUG_KERNEL && !S390
620         help
621           Say Y here to enable the kernel to act as a watchdog to detect
622           hard and soft lockups.
623 
624           Softlockups are bugs that cause the kernel to loop in kernel
625           mode for more than 20 seconds, without giving other tasks a
626           chance to run.  The current stack trace is displayed upon
627           detection and the system will stay locked up.
628 
629           Hardlockups are bugs that cause the CPU to loop in kernel mode
630           for more than 10 seconds, without letting other interrupts have a
631           chance to run.  The current stack trace is displayed upon detection
632           and the system will stay locked up.
633 
634           The overhead should be minimal.  A periodic hrtimer runs to
635           generate interrupts and kick the watchdog task every 4 seconds.
636           An NMI is generated every 10 seconds or so to check for hardlockups.
637 
638           The frequency of hrtimer and NMI events and the soft and hard lockup
639           thresholds can be controlled through the sysctl watchdog_thresh.
640 
641 config HARDLOCKUP_DETECTOR
642         def_bool y
643         depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG
644         depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
645 
646 config BOOTPARAM_HARDLOCKUP_PANIC
647         bool "Panic (Reboot) On Hard Lockups"
648         depends on HARDLOCKUP_DETECTOR
649         help
650           Say Y here to enable the kernel to panic on "hard lockups",
651           which are bugs that cause the kernel to loop in kernel
652           mode with interrupts disabled for more than 10 seconds (configurable
653           using the watchdog_thresh sysctl).
654 
655           Say N if unsure.
656 
657 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
658         int
659         depends on HARDLOCKUP_DETECTOR
660         range 0 1
661         default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
662         default 1 if BOOTPARAM_HARDLOCKUP_PANIC
663 
664 config BOOTPARAM_SOFTLOCKUP_PANIC
665         bool "Panic (Reboot) On Soft Lockups"
666         depends on LOCKUP_DETECTOR
667         help
668           Say Y here to enable the kernel to panic on "soft lockups",
669           which are bugs that cause the kernel to loop in kernel
670           mode for more than 20 seconds (configurable using the watchdog_thresh
671           sysctl), without giving other tasks a chance to run.
672 
673           The panic can be used in combination with panic_timeout,
674           to cause the system to reboot automatically after a
675           lockup has been detected. This feature is useful for
676           high-availability systems that have uptime guarantees and
677           where a lockup must be resolved ASAP.
678 
679           Say N if unsure.
680 
681 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
682         int
683         depends on LOCKUP_DETECTOR
684         range 0 1
685         default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
686         default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
687 
688 config DETECT_HUNG_TASK
689         bool "Detect Hung Tasks"
690         depends on DEBUG_KERNEL
691         default LOCKUP_DETECTOR
692         help
693           Say Y here to enable the kernel to detect "hung tasks",
694           which are bugs that cause the task to be stuck in
695           uninterruptible "D" state indefinitiley.
696 
697           When a hung task is detected, the kernel will print the
698           current stack trace (which you should report), but the
699           task will stay in uninterruptible state. If lockdep is
700           enabled then all held locks will also be reported. This
701           feature has negligible overhead.
702 
703 config DEFAULT_HUNG_TASK_TIMEOUT
704         int "Default timeout for hung task detection (in seconds)"
705         depends on DETECT_HUNG_TASK
706         default 120
707         help
708           This option controls the default timeout (in seconds) used
709           to determine when a task has become non-responsive and should
710           be considered hung.
711 
712           It can be adjusted at runtime via the kernel.hung_task_timeout_secs
713           sysctl or by writing a value to
714           /proc/sys/kernel/hung_task_timeout_secs.
715 
716           A timeout of 0 disables the check.  The default is two minutes.
717           Keeping the default should be fine in most cases.
718 
719 config BOOTPARAM_HUNG_TASK_PANIC
720         bool "Panic (Reboot) On Hung Tasks"
721         depends on DETECT_HUNG_TASK
722         help
723           Say Y here to enable the kernel to panic on "hung tasks",
724           which are bugs that cause the kernel to leave a task stuck
725           in uninterruptible "D" state.
726 
727           The panic can be used in combination with panic_timeout,
728           to cause the system to reboot automatically after a
729           hung task has been detected. This feature is useful for
730           high-availability systems that have uptime guarantees and
731           where a hung tasks must be resolved ASAP.
732 
733           Say N if unsure.
734 
735 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
736         int
737         depends on DETECT_HUNG_TASK
738         range 0 1
739         default 0 if !BOOTPARAM_HUNG_TASK_PANIC
740         default 1 if BOOTPARAM_HUNG_TASK_PANIC
741 
742 endmenu # "Debug lockups and hangs"
743 
744 config PANIC_ON_OOPS
745         bool "Panic on Oops"
746         help
747           Say Y here to enable the kernel to panic when it oopses. This
748           has the same effect as setting oops=panic on the kernel command
749           line.
750 
751           This feature is useful to ensure that the kernel does not do
752           anything erroneous after an oops which could result in data
753           corruption or other issues.
754 
755           Say N if unsure.
756 
757 config PANIC_ON_OOPS_VALUE
758         int
759         range 0 1
760         default 0 if !PANIC_ON_OOPS
761         default 1 if PANIC_ON_OOPS
762 
763 config PANIC_TIMEOUT
764         int "panic timeout"
765         default 0
766         help
767           Set the timeout value (in seconds) until a reboot occurs when the
768           the kernel panics. If n = 0, then we wait forever. A timeout
769           value n > 0 will wait n seconds before rebooting, while a timeout
770           value n < 0 will reboot immediately.
771 
772 config SCHED_DEBUG
773         bool "Collect scheduler debugging info"
774         depends on DEBUG_KERNEL && PROC_FS
775         default y
776         help
777           If you say Y here, the /proc/sched_debug file will be provided
778           that can help debug the scheduler. The runtime overhead of this
779           option is minimal.
780 
781 config SCHEDSTATS
782         bool "Collect scheduler statistics"
783         depends on DEBUG_KERNEL && PROC_FS
784         help
785           If you say Y here, additional code will be inserted into the
786           scheduler and related routines to collect statistics about
787           scheduler behavior and provide them in /proc/schedstat.  These
788           stats may be useful for both tuning and debugging the scheduler
789           If you aren't debugging the scheduler or trying to tune a specific
790           application, you can say N to avoid the very slight overhead
791           this adds.
792 
793 config TIMER_STATS
794         bool "Collect kernel timers statistics"
795         depends on DEBUG_KERNEL && PROC_FS
796         help
797           If you say Y here, additional code will be inserted into the
798           timer routines to collect statistics about kernel timers being
799           reprogrammed. The statistics can be read from /proc/timer_stats.
800           The statistics collection is started by writing 1 to /proc/timer_stats,
801           writing 0 stops it. This feature is useful to collect information
802           about timer usage patterns in kernel and userspace. This feature
803           is lightweight if enabled in the kernel config but not activated
804           (it defaults to deactivated on bootup and will only be activated
805           if some application like powertop activates it explicitly).
806 
807 config DEBUG_PREEMPT
808         bool "Debug preemptible kernel"
809         depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
810         default y
811         help
812           If you say Y here then the kernel will use a debug variant of the
813           commonly used smp_processor_id() function and will print warnings
814           if kernel code uses it in a preemption-unsafe way. Also, the kernel
815           will detect preemption count underflows.
816 
817 menu "Lock Debugging (spinlocks, mutexes, etc...)"
818 
819 config DEBUG_RT_MUTEXES
820         bool "RT Mutex debugging, deadlock detection"
821         depends on DEBUG_KERNEL && RT_MUTEXES
822         help
823          This allows rt mutex semantics violations and rt mutex related
824          deadlocks (lockups) to be detected and reported automatically.
825 
826 config DEBUG_PI_LIST
827         bool
828         default y
829         depends on DEBUG_RT_MUTEXES
830 
831 config RT_MUTEX_TESTER
832         bool "Built-in scriptable tester for rt-mutexes"
833         depends on DEBUG_KERNEL && RT_MUTEXES
834         help
835           This option enables a rt-mutex tester.
836 
837 config DEBUG_SPINLOCK
838         bool "Spinlock and rw-lock debugging: basic checks"
839         depends on DEBUG_KERNEL
840         select UNINLINE_SPIN_UNLOCK
841         help
842           Say Y here and build SMP to catch missing spinlock initialization
843           and certain other kinds of spinlock errors commonly made.  This is
844           best used in conjunction with the NMI watchdog so that spinlock
845           deadlocks are also debuggable.
846 
847 config DEBUG_MUTEXES
848         bool "Mutex debugging: basic checks"
849         depends on DEBUG_KERNEL
850         help
851          This feature allows mutex semantics violations to be detected and
852          reported.
853 
854 config DEBUG_WW_MUTEX_SLOWPATH
855         bool "Wait/wound mutex debugging: Slowpath testing"
856         depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
857         select DEBUG_LOCK_ALLOC
858         select DEBUG_SPINLOCK
859         select DEBUG_MUTEXES
860         help
861          This feature enables slowpath testing for w/w mutex users by
862          injecting additional -EDEADLK wound/backoff cases. Together with
863          the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
864          will test all possible w/w mutex interface abuse with the
865          exception of simply not acquiring all the required locks.
866 
867 config DEBUG_LOCK_ALLOC
868         bool "Lock debugging: detect incorrect freeing of live locks"
869         depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
870         select DEBUG_SPINLOCK
871         select DEBUG_MUTEXES
872         select LOCKDEP
873         help
874          This feature will check whether any held lock (spinlock, rwlock,
875          mutex or rwsem) is incorrectly freed by the kernel, via any of the
876          memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
877          vfree(), etc.), whether a live lock is incorrectly reinitialized via
878          spin_lock_init()/mutex_init()/etc., or whether there is any lock
879          held during task exit.
880 
881 config PROVE_LOCKING
882         bool "Lock debugging: prove locking correctness"
883         depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
884         select LOCKDEP
885         select DEBUG_SPINLOCK
886         select DEBUG_MUTEXES
887         select DEBUG_LOCK_ALLOC
888         select TRACE_IRQFLAGS
889         default n
890         help
891          This feature enables the kernel to prove that all locking
892          that occurs in the kernel runtime is mathematically
893          correct: that under no circumstance could an arbitrary (and
894          not yet triggered) combination of observed locking
895          sequences (on an arbitrary number of CPUs, running an
896          arbitrary number of tasks and interrupt contexts) cause a
897          deadlock.
898 
899          In short, this feature enables the kernel to report locking
900          related deadlocks before they actually occur.
901 
902          The proof does not depend on how hard and complex a
903          deadlock scenario would be to trigger: how many
904          participant CPUs, tasks and irq-contexts would be needed
905          for it to trigger. The proof also does not depend on
906          timing: if a race and a resulting deadlock is possible
907          theoretically (no matter how unlikely the race scenario
908          is), it will be proven so and will immediately be
909          reported by the kernel (once the event is observed that
910          makes the deadlock theoretically possible).
911 
912          If a deadlock is impossible (i.e. the locking rules, as
913          observed by the kernel, are mathematically correct), the
914          kernel reports nothing.
915 
916          NOTE: this feature can also be enabled for rwlocks, mutexes
917          and rwsems - in which case all dependencies between these
918          different locking variants are observed and mapped too, and
919          the proof of observed correctness is also maintained for an
920          arbitrary combination of these separate locking variants.
921 
922          For more details, see Documentation/lockdep-design.txt.
923 
924 config LOCKDEP
925         bool
926         depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
927         select STACKTRACE
928         select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC
929         select KALLSYMS
930         select KALLSYMS_ALL
931 
932 config LOCK_STAT
933         bool "Lock usage statistics"
934         depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
935         select LOCKDEP
936         select DEBUG_SPINLOCK
937         select DEBUG_MUTEXES
938         select DEBUG_LOCK_ALLOC
939         default n
940         help
941          This feature enables tracking lock contention points
942 
943          For more details, see Documentation/lockstat.txt
944 
945          This also enables lock events required by "perf lock",
946          subcommand of perf.
947          If you want to use "perf lock", you also need to turn on
948          CONFIG_EVENT_TRACING.
949 
950          CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
951          (CONFIG_LOCKDEP defines "acquire" and "release" events.)
952 
953 config DEBUG_LOCKDEP
954         bool "Lock dependency engine debugging"
955         depends on DEBUG_KERNEL && LOCKDEP
956         help
957           If you say Y here, the lock dependency engine will do
958           additional runtime checks to debug itself, at the price
959           of more runtime overhead.
960 
961 config DEBUG_ATOMIC_SLEEP
962         bool "Sleep inside atomic section checking"
963         select PREEMPT_COUNT
964         depends on DEBUG_KERNEL
965         help
966           If you say Y here, various routines which may sleep will become very
967           noisy if they are called inside atomic sections: when a spinlock is
968           held, inside an rcu read side critical section, inside preempt disabled
969           sections, inside an interrupt, etc...
970 
971 config DEBUG_LOCKING_API_SELFTESTS
972         bool "Locking API boot-time self-tests"
973         depends on DEBUG_KERNEL
974         help
975           Say Y here if you want the kernel to run a short self-test during
976           bootup. The self-test checks whether common types of locking bugs
977           are detected by debugging mechanisms or not. (if you disable
978           lock debugging then those bugs wont be detected of course.)
979           The following locking APIs are covered: spinlocks, rwlocks,
980           mutexes and rwsems.
981 
982 config LOCK_TORTURE_TEST
983         tristate "torture tests for locking"
984         depends on DEBUG_KERNEL
985         select TORTURE_TEST
986         default n
987         help
988           This option provides a kernel module that runs torture tests
989           on kernel locking primitives.  The kernel module may be built
990           after the fact on the running kernel to be tested, if desired.
991 
992           Say Y here if you want kernel locking-primitive torture tests
993           to be built into the kernel.
994           Say M if you want these torture tests to build as a module.
995           Say N if you are unsure.
996 
997 endmenu # lock debugging
998 
999 config TRACE_IRQFLAGS
1000         bool
1001         help
1002           Enables hooks to interrupt enabling and disabling for
1003           either tracing or lock debugging.
1004 
1005 config STACKTRACE
1006         bool
1007         depends on STACKTRACE_SUPPORT
1008 
1009 config DEBUG_KOBJECT
1010         bool "kobject debugging"
1011         depends on DEBUG_KERNEL
1012         help
1013           If you say Y here, some extra kobject debugging messages will be sent
1014           to the syslog. 
1015 
1016 config DEBUG_KOBJECT_RELEASE
1017         bool "kobject release debugging"
1018         depends on DEBUG_OBJECTS_TIMERS
1019         help
1020           kobjects are reference counted objects.  This means that their
1021           last reference count put is not predictable, and the kobject can
1022           live on past the point at which a driver decides to drop it's
1023           initial reference to the kobject gained on allocation.  An
1024           example of this would be a struct device which has just been
1025           unregistered.
1026 
1027           However, some buggy drivers assume that after such an operation,
1028           the memory backing the kobject can be immediately freed.  This
1029           goes completely against the principles of a refcounted object.
1030 
1031           If you say Y here, the kernel will delay the release of kobjects
1032           on the last reference count to improve the visibility of this
1033           kind of kobject release bug.
1034 
1035 config HAVE_DEBUG_BUGVERBOSE
1036         bool
1037 
1038 config DEBUG_BUGVERBOSE
1039         bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
1040         depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
1041         default y
1042         help
1043           Say Y here to make BUG() panics output the file name and line number
1044           of the BUG call as well as the EIP and oops trace.  This aids
1045           debugging but costs about 70-100K of memory.
1046 
1047 config DEBUG_LIST
1048         bool "Debug linked list manipulation"
1049         depends on DEBUG_KERNEL
1050         help
1051           Enable this to turn on extended checks in the linked-list
1052           walking routines.
1053 
1054           If unsure, say N.
1055 
1056 config DEBUG_SG
1057         bool "Debug SG table operations"
1058         depends on DEBUG_KERNEL
1059         help
1060           Enable this to turn on checks on scatter-gather tables. This can
1061           help find problems with drivers that do not properly initialize
1062           their sg tables.
1063 
1064           If unsure, say N.
1065 
1066 config DEBUG_NOTIFIERS
1067         bool "Debug notifier call chains"
1068         depends on DEBUG_KERNEL
1069         help
1070           Enable this to turn on sanity checking for notifier call chains.
1071           This is most useful for kernel developers to make sure that
1072           modules properly unregister themselves from notifier chains.
1073           This is a relatively cheap check but if you care about maximum
1074           performance, say N.
1075 
1076 config DEBUG_CREDENTIALS
1077         bool "Debug credential management"
1078         depends on DEBUG_KERNEL
1079         help
1080           Enable this to turn on some debug checking for credential
1081           management.  The additional code keeps track of the number of
1082           pointers from task_structs to any given cred struct, and checks to
1083           see that this number never exceeds the usage count of the cred
1084           struct.
1085 
1086           Furthermore, if SELinux is enabled, this also checks that the
1087           security pointer in the cred struct is never seen to be invalid.
1088 
1089           If unsure, say N.
1090 
1091 menu "RCU Debugging"
1092 
1093 config PROVE_RCU
1094         bool "RCU debugging: prove RCU correctness"
1095         depends on PROVE_LOCKING
1096         default n
1097         help
1098          This feature enables lockdep extensions that check for correct
1099          use of RCU APIs.  This is currently under development.  Say Y
1100          if you want to debug RCU usage or help work on the PROVE_RCU
1101          feature.
1102 
1103          Say N if you are unsure.
1104 
1105 config PROVE_RCU_REPEATEDLY
1106         bool "RCU debugging: don't disable PROVE_RCU on first splat"
1107         depends on PROVE_RCU
1108         default n
1109         help
1110          By itself, PROVE_RCU will disable checking upon issuing the
1111          first warning (or "splat").  This feature prevents such
1112          disabling, allowing multiple RCU-lockdep warnings to be printed
1113          on a single reboot.
1114 
1115          Say Y to allow multiple RCU-lockdep warnings per boot.
1116 
1117          Say N if you are unsure.
1118 
1119 config PROVE_RCU_DELAY
1120         bool "RCU debugging: preemptible RCU race provocation"
1121         depends on DEBUG_KERNEL && PREEMPT_RCU
1122         default n
1123         help
1124          There is a class of races that involve an unlikely preemption
1125          of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
1126          been set to INT_MIN.  This feature inserts a delay at that
1127          point to increase the probability of these races.
1128 
1129          Say Y to increase probability of preemption of __rcu_read_unlock().
1130 
1131          Say N if you are unsure.
1132 
1133 config SPARSE_RCU_POINTER
1134         bool "RCU debugging: sparse-based checks for pointer usage"
1135         default n
1136         help
1137          This feature enables the __rcu sparse annotation for
1138          RCU-protected pointers.  This annotation will cause sparse
1139          to flag any non-RCU used of annotated pointers.  This can be
1140          helpful when debugging RCU usage.  Please note that this feature
1141          is not intended to enforce code cleanliness; it is instead merely
1142          a debugging aid.
1143 
1144          Say Y to make sparse flag questionable use of RCU-protected pointers
1145 
1146          Say N if you are unsure.
1147 
1148 config TORTURE_TEST
1149         tristate
1150         default n
1151 
1152 config RCU_TORTURE_TEST
1153         tristate "torture tests for RCU"
1154         depends on DEBUG_KERNEL
1155         select TORTURE_TEST
1156         default n
1157         help
1158           This option provides a kernel module that runs torture tests
1159           on the RCU infrastructure.  The kernel module may be built
1160           after the fact on the running kernel to be tested, if desired.
1161 
1162           Say Y here if you want RCU torture tests to be built into
1163           the kernel.
1164           Say M if you want the RCU torture tests to build as a module.
1165           Say N if you are unsure.
1166 
1167 config RCU_TORTURE_TEST_RUNNABLE
1168         bool "torture tests for RCU runnable by default"
1169         depends on RCU_TORTURE_TEST = y
1170         default n
1171         help
1172           This option provides a way to build the RCU torture tests
1173           directly into the kernel without them starting up at boot
1174           time.  You can use /proc/sys/kernel/rcutorture_runnable
1175           to manually override this setting.  This /proc file is
1176           available only when the RCU torture tests have been built
1177           into the kernel.
1178 
1179           Say Y here if you want the RCU torture tests to start during
1180           boot (you probably don't).
1181           Say N here if you want the RCU torture tests to start only
1182           after being manually enabled via /proc.
1183 
1184 config RCU_CPU_STALL_TIMEOUT
1185         int "RCU CPU stall timeout in seconds"
1186         depends on RCU_STALL_COMMON
1187         range 3 300
1188         default 21
1189         help
1190           If a given RCU grace period extends more than the specified
1191           number of seconds, a CPU stall warning is printed.  If the
1192           RCU grace period persists, additional CPU stall warnings are
1193           printed at more widely spaced intervals.
1194 
1195 config RCU_CPU_STALL_VERBOSE
1196         bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
1197         depends on TREE_PREEMPT_RCU
1198         default y
1199         help
1200           This option causes RCU to printk detailed per-task information
1201           for any tasks that are stalling the current RCU grace period.
1202 
1203           Say N if you are unsure.
1204 
1205           Say Y if you want to enable such checks.
1206 
1207 config RCU_CPU_STALL_INFO
1208         bool "Print additional diagnostics on RCU CPU stall"
1209         depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
1210         default n
1211         help
1212           For each stalled CPU that is aware of the current RCU grace
1213           period, print out additional per-CPU diagnostic information
1214           regarding scheduling-clock ticks, idle state, and,
1215           for RCU_FAST_NO_HZ kernels, idle-entry state.
1216 
1217           Say N if you are unsure.
1218 
1219           Say Y if you want to enable such diagnostics.
1220 
1221 config RCU_TRACE
1222         bool "Enable tracing for RCU"
1223         depends on DEBUG_KERNEL
1224         select TRACE_CLOCK
1225         help
1226           This option provides tracing in RCU which presents stats
1227           in debugfs for debugging RCU implementation.
1228 
1229           Say Y here if you want to enable RCU tracing
1230           Say N if you are unsure.
1231 
1232 endmenu # "RCU Debugging"
1233 
1234 config DEBUG_BLOCK_EXT_DEVT
1235         bool "Force extended block device numbers and spread them"
1236         depends on DEBUG_KERNEL
1237         depends on BLOCK
1238         default n
1239         help
1240           BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1241           SOME DISTRIBUTIONS.  DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1242           YOU ARE DOING.  Distros, please enable this and fix whatever
1243           is broken.
1244 
1245           Conventionally, block device numbers are allocated from
1246           predetermined contiguous area.  However, extended block area
1247           may introduce non-contiguous block device numbers.  This
1248           option forces most block device numbers to be allocated from
1249           the extended space and spreads them to discover kernel or
1250           userland code paths which assume predetermined contiguous
1251           device number allocation.
1252 
1253           Note that turning on this debug option shuffles all the
1254           device numbers for all IDE and SCSI devices including libata
1255           ones, so root partition specified using device number
1256           directly (via rdev or root=MAJ:MIN) won't work anymore.
1257           Textual device names (root=/dev/sdXn) will continue to work.
1258 
1259           Say N if you are unsure.
1260 
1261 config NOTIFIER_ERROR_INJECTION
1262         tristate "Notifier error injection"
1263         depends on DEBUG_KERNEL
1264         select DEBUG_FS
1265         help
1266           This option provides the ability to inject artificial errors to
1267           specified notifier chain callbacks. It is useful to test the error
1268           handling of notifier call chain failures.
1269 
1270           Say N if unsure.
1271 
1272 config CPU_NOTIFIER_ERROR_INJECT
1273         tristate "CPU notifier error injection module"
1274         depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
1275         help
1276           This option provides a kernel module that can be used to test
1277           the error handling of the cpu notifiers by injecting artificial
1278           errors to CPU notifier chain callbacks.  It is controlled through
1279           debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu
1280 
1281           If the notifier call chain should be failed with some events
1282           notified, write the error code to "actions/<notifier event>/error".
1283 
1284           Example: Inject CPU offline error (-1 == -EPERM)
1285 
1286           # cd /sys/kernel/debug/notifier-error-inject/cpu
1287           # echo -1 > actions/CPU_DOWN_PREPARE/error
1288           # echo 0 > /sys/devices/system/cpu/cpu1/online
1289           bash: echo: write error: Operation not permitted
1290 
1291           To compile this code as a module, choose M here: the module will
1292           be called cpu-notifier-error-inject.
1293 
1294           If unsure, say N.
1295 
1296 config PM_NOTIFIER_ERROR_INJECT
1297         tristate "PM notifier error injection module"
1298         depends on PM && NOTIFIER_ERROR_INJECTION
1299         default m if PM_DEBUG
1300         help
1301           This option provides the ability to inject artificial errors to
1302           PM notifier chain callbacks.  It is controlled through debugfs
1303           interface /sys/kernel/debug/notifier-error-inject/pm
1304 
1305           If the notifier call chain should be failed with some events
1306           notified, write the error code to "actions/<notifier event>/error".
1307 
1308           Example: Inject PM suspend error (-12 = -ENOMEM)
1309 
1310           # cd /sys/kernel/debug/notifier-error-inject/pm/
1311           # echo -12 > actions/PM_SUSPEND_PREPARE/error
1312           # echo mem > /sys/power/state
1313           bash: echo: write error: Cannot allocate memory
1314 
1315           To compile this code as a module, choose M here: the module will
1316           be called pm-notifier-error-inject.
1317 
1318           If unsure, say N.
1319 
1320 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1321         tristate "OF reconfig notifier error injection module"
1322         depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1323         help
1324           This option provides the ability to inject artificial errors to
1325           OF reconfig notifier chain callbacks.  It is controlled
1326           through debugfs interface under
1327           /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1328 
1329           If the notifier call chain should be failed with some events
1330           notified, write the error code to "actions/<notifier event>/error".
1331 
1332           To compile this code as a module, choose M here: the module will
1333           be called of-reconfig-notifier-error-inject.
1334 
1335           If unsure, say N.
1336 
1337 config FAULT_INJECTION
1338         bool "Fault-injection framework"
1339         depends on DEBUG_KERNEL
1340         help
1341           Provide fault-injection framework.
1342           For more details, see Documentation/fault-injection/.
1343 
1344 config FAILSLAB
1345         bool "Fault-injection capability for kmalloc"
1346         depends on FAULT_INJECTION
1347         depends on SLAB || SLUB
1348         help
1349           Provide fault-injection capability for kmalloc.
1350 
1351 config FAIL_PAGE_ALLOC
1352         bool "Fault-injection capabilitiy for alloc_pages()"
1353         depends on FAULT_INJECTION
1354         help
1355           Provide fault-injection capability for alloc_pages().
1356 
1357 config FAIL_MAKE_REQUEST
1358         bool "Fault-injection capability for disk IO"
1359         depends on FAULT_INJECTION && BLOCK
1360         help
1361           Provide fault-injection capability for disk IO.
1362 
1363 config FAIL_IO_TIMEOUT
1364         bool "Fault-injection capability for faking disk interrupts"
1365         depends on FAULT_INJECTION && BLOCK
1366         help
1367           Provide fault-injection capability on end IO handling. This
1368           will make the block layer "forget" an interrupt as configured,
1369           thus exercising the error handling.
1370 
1371           Only works with drivers that use the generic timeout handling,
1372           for others it wont do anything.
1373 
1374 config FAIL_MMC_REQUEST
1375         bool "Fault-injection capability for MMC IO"
1376         select DEBUG_FS
1377         depends on FAULT_INJECTION && MMC
1378         help
1379           Provide fault-injection capability for MMC IO.
1380           This will make the mmc core return data errors. This is
1381           useful to test the error handling in the mmc block device
1382           and to test how the mmc host driver handles retries from
1383           the block device.
1384 
1385 config FAULT_INJECTION_DEBUG_FS
1386         bool "Debugfs entries for fault-injection capabilities"
1387         depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1388         help
1389           Enable configuration of fault-injection capabilities via debugfs.
1390 
1391 config FAULT_INJECTION_STACKTRACE_FILTER
1392         bool "stacktrace filter for fault-injection capabilities"
1393         depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1394         depends on !X86_64
1395         select STACKTRACE
1396         select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC
1397         help
1398           Provide stacktrace filter for fault-injection capabilities
1399 
1400 config LATENCYTOP
1401         bool "Latency measuring infrastructure"
1402         depends on HAVE_LATENCYTOP_SUPPORT
1403         depends on DEBUG_KERNEL
1404         depends on STACKTRACE_SUPPORT
1405         depends on PROC_FS
1406         select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC
1407         select KALLSYMS
1408         select KALLSYMS_ALL
1409         select STACKTRACE
1410         select SCHEDSTATS
1411         select SCHED_DEBUG
1412         help
1413           Enable this option if you want to use the LatencyTOP tool
1414           to find out which userspace is blocking on what kernel operations.
1415 
1416 config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1417         bool
1418 
1419 config DEBUG_STRICT_USER_COPY_CHECKS
1420         bool "Strict user copy size checks"
1421         depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1422         depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING
1423         help
1424           Enabling this option turns a certain set of sanity checks for user
1425           copy operations into compile time failures.
1426 
1427           The copy_from_user() etc checks are there to help test if there
1428           are sufficient security checks on the length argument of
1429           the copy operation, by having gcc prove that the argument is
1430           within bounds.
1431 
1432           If unsure, say N.
1433 
1434 source kernel/trace/Kconfig
1435 
1436 menu "Runtime Testing"
1437 
1438 config LKDTM
1439         tristate "Linux Kernel Dump Test Tool Module"
1440         depends on DEBUG_FS
1441         depends on BLOCK
1442         default n
1443         help
1444         This module enables testing of the different dumping mechanisms by
1445         inducing system failures at predefined crash points.
1446         If you don't need it: say N
1447         Choose M here to compile this code as a module. The module will be
1448         called lkdtm.
1449 
1450         Documentation on how to use the module can be found in
1451         Documentation/fault-injection/provoke-crashes.txt
1452 
1453 config TEST_LIST_SORT
1454         bool "Linked list sorting test"
1455         depends on DEBUG_KERNEL
1456         help
1457           Enable this to turn on 'list_sort()' function test. This test is
1458           executed only once during system boot, so affects only boot time.
1459 
1460           If unsure, say N.
1461 
1462 config KPROBES_SANITY_TEST
1463         bool "Kprobes sanity tests"
1464         depends on DEBUG_KERNEL
1465         depends on KPROBES
1466         default n
1467         help
1468           This option provides for testing basic kprobes functionality on
1469           boot. A sample kprobe, jprobe and kretprobe are inserted and
1470           verified for functionality.
1471 
1472           Say N if you are unsure.
1473 
1474 config BACKTRACE_SELF_TEST
1475         tristate "Self test for the backtrace code"
1476         depends on DEBUG_KERNEL
1477         default n
1478         help
1479           This option provides a kernel module that can be used to test
1480           the kernel stack backtrace code. This option is not useful
1481           for distributions or general kernels, but only for kernel
1482           developers working on architecture code.
1483 
1484           Note that if you want to also test saved backtraces, you will
1485           have to enable STACKTRACE as well.
1486 
1487           Say N if you are unsure.
1488 
1489 config RBTREE_TEST
1490         tristate "Red-Black tree test"
1491         depends on DEBUG_KERNEL
1492         help
1493           A benchmark measuring the performance of the rbtree library.
1494           Also includes rbtree invariant checks.
1495 
1496 config INTERVAL_TREE_TEST
1497         tristate "Interval tree test"
1498         depends on m && DEBUG_KERNEL
1499         help
1500           A benchmark measuring the performance of the interval tree library
1501 
1502 config PERCPU_TEST
1503         tristate "Per cpu operations test"
1504         depends on m && DEBUG_KERNEL
1505         help
1506           Enable this option to build test module which validates per-cpu
1507           operations.
1508 
1509           If unsure, say N.
1510 
1511 config ATOMIC64_SELFTEST
1512         bool "Perform an atomic64_t self-test at boot"
1513         help
1514           Enable this option to test the atomic64_t functions at boot.
1515 
1516           If unsure, say N.
1517 
1518 config ASYNC_RAID6_TEST
1519         tristate "Self test for hardware accelerated raid6 recovery"
1520         depends on ASYNC_RAID6_RECOV
1521         select ASYNC_MEMCPY
1522         ---help---
1523           This is a one-shot self test that permutes through the
1524           recovery of all the possible two disk failure scenarios for a
1525           N-disk array.  Recovery is performed with the asynchronous
1526           raid6 recovery routines, and will optionally use an offload
1527           engine if one is available.
1528 
1529           If unsure, say N.
1530 
1531 config TEST_STRING_HELPERS
1532         tristate "Test functions located in the string_helpers module at runtime"
1533 
1534 config TEST_KSTRTOX
1535         tristate "Test kstrto*() family of functions at runtime"
1536 
1537 endmenu # runtime tests
1538 
1539 config PROVIDE_OHCI1394_DMA_INIT
1540         bool "Remote debugging over FireWire early on boot"
1541         depends on PCI && X86
1542         help
1543           If you want to debug problems which hang or crash the kernel early
1544           on boot and the crashing machine has a FireWire port, you can use
1545           this feature to remotely access the memory of the crashed machine
1546           over FireWire. This employs remote DMA as part of the OHCI1394
1547           specification which is now the standard for FireWire controllers.
1548 
1549           With remote DMA, you can monitor the printk buffer remotely using
1550           firescope and access all memory below 4GB using fireproxy from gdb.
1551           Even controlling a kernel debugger is possible using remote DMA.
1552 
1553           Usage:
1554 
1555           If ohci1394_dma=early is used as boot parameter, it will initialize
1556           all OHCI1394 controllers which are found in the PCI config space.
1557 
1558           As all changes to the FireWire bus such as enabling and disabling
1559           devices cause a bus reset and thereby disable remote DMA for all
1560           devices, be sure to have the cable plugged and FireWire enabled on
1561           the debugging host before booting the debug target for debugging.
1562 
1563           This code (~1k) is freed after boot. By then, the firewire stack
1564           in charge of the OHCI-1394 controllers should be used instead.
1565 
1566           See Documentation/debugging-via-ohci1394.txt for more information.
1567 
1568 config BUILD_DOCSRC
1569         bool "Build targets in Documentation/ tree"
1570         depends on HEADERS_CHECK
1571         help
1572           This option attempts to build objects from the source files in the
1573           kernel Documentation/ tree.
1574 
1575           Say N if you are unsure.
1576 
1577 config DMA_API_DEBUG
1578         bool "Enable debugging of DMA-API usage"
1579         depends on HAVE_DMA_API_DEBUG
1580         help
1581           Enable this option to debug the use of the DMA API by device drivers.
1582           With this option you will be able to detect common bugs in device
1583           drivers like double-freeing of DMA mappings or freeing mappings that
1584           were never allocated.
1585 
1586           This also attempts to catch cases where a page owned by DMA is
1587           accessed by the cpu in a way that could cause data corruption.  For
1588           example, this enables cow_user_page() to check that the source page is
1589           not undergoing DMA.
1590 
1591           This option causes a performance degradation.  Use only if you want to
1592           debug device drivers and dma interactions.
1593 
1594           If unsure, say N.
1595 
1596 config TEST_MODULE
1597         tristate "Test module loading with 'hello world' module"
1598         default n
1599         depends on m
1600         help
1601           This builds the "test_module" module that emits "Hello, world"
1602           on printk when loaded. It is designed to be used for basic
1603           evaluation of the module loading subsystem (for example when
1604           validating module verification). It lacks any extra dependencies,
1605           and will not normally be loaded by the system unless explicitly
1606           requested by name.
1607 
1608           If unsure, say N.
1609 
1610 config TEST_USER_COPY
1611         tristate "Test user/kernel boundary protections"
1612         default n
1613         depends on m
1614         help
1615           This builds the "test_user_copy" module that runs sanity checks
1616           on the copy_to/from_user infrastructure, making sure basic
1617           user/kernel boundary testing is working. If it fails to load,
1618           a regression has been detected in the user/kernel memory boundary
1619           protections.
1620 
1621           If unsure, say N.
1622 
1623 source "samples/Kconfig"
1624 
1625 source "lib/Kconfig.kgdb"
1626 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us