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Linus Torvalds1da177e2005-04-16 15:20:36 -07001
2config PRINTK_TIME
3 bool "Show timing information on printks"
Randy Dunlapd3b8b6e2006-12-06 20:36:38 -08004 depends on PRINTK
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 help
Kay Sievers649e6ee2012-05-10 04:30:45 +02006 Selecting this option causes time stamps of the printk()
7 messages to be added to the output of the syslog() system
8 call and at the console.
9
10 The timestamp is always recorded internally, and exported
11 to /dev/kmsg. This flag just specifies if the timestamp should
12 be included, not that the timestamp is recorded.
13
14 The behavior is also controlled by the kernel command line
15 parameter printk.time=1. See Documentation/kernel-parameters.txt
Linus Torvalds1da177e2005-04-16 15:20:36 -070016
Mandeep Singh Baines5af5bcb2011-03-22 16:34:23 -070017config DEFAULT_MESSAGE_LOGLEVEL
18 int "Default message log level (1-7)"
19 range 1 7
20 default "4"
21 help
22 Default log level for printk statements with no specified priority.
23
24 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
25 that are auditing their logs closely may want to set it to a lower
26 priority.
27
Dave Hansen6dfc0662013-07-01 13:04:46 -070028menu "Compile-time checks and compiler options"
29
30config DEBUG_INFO
31 bool "Compile the kernel with debug info"
32 depends on DEBUG_KERNEL
33 help
34 If you say Y here the resulting kernel image will include
35 debugging info resulting in a larger kernel image.
36 This adds debug symbols to the kernel and modules (gcc -g), and
37 is needed if you intend to use kernel crashdump or binary object
38 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
39 Say Y here only if you plan to debug the kernel.
40
41 If unsure, say N.
42
43config DEBUG_INFO_REDUCED
44 bool "Reduce debugging information"
45 depends on DEBUG_INFO
46 help
47 If you say Y here gcc is instructed to generate less debugging
48 information for structure types. This means that tools that
49 need full debugging information (like kgdb or systemtap) won't
50 be happy. But if you merely need debugging information to
51 resolve line numbers there is no loss. Advantage is that
52 build directory object sizes shrink dramatically over a full
53 DEBUG_INFO build and compile times are reduced too.
54 Only works with newer gcc versions.
55
Jeff Garzikde488442007-10-25 04:06:13 -040056config ENABLE_WARN_DEPRECATED
57 bool "Enable __deprecated logic"
58 default y
59 help
60 Enable the __deprecated logic in the kernel build.
61 Disable this to suppress the "warning: 'foo' is deprecated
62 (declared at kernel/power/somefile.c:1234)" messages.
63
Andrew Mortoncebc04b2006-08-14 22:43:18 -070064config ENABLE_MUST_CHECK
65 bool "Enable __must_check logic"
66 default y
67 help
68 Enable the __must_check logic in the kernel build. Disable this to
69 suppress the "warning: ignoring return value of 'foo', declared with
70 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
Andi Kleen35bb5b12008-02-22 15:15:03 +010072config FRAME_WARN
73 int "Warn for stack frames larger than (needs gcc 4.4)"
74 range 0 8192
75 default 1024 if !64BIT
76 default 2048 if 64BIT
77 help
78 Tell gcc to warn at build time for stack frames larger than this.
79 Setting this too low will cause a lot of warnings.
80 Setting it to 0 disables the warning.
81 Requires gcc 4.4
82
Randy Dunlap99657c72009-09-18 12:49:22 -070083config STRIP_ASM_SYMS
84 bool "Strip assembler-generated symbols during link"
85 default n
86 help
87 Strip internal assembler-generated symbols during a link (symbols
88 that look like '.Lxxx') so they don't pollute the output of
89 get_wchan() and suchlike.
90
Andi Kleen1873e872012-03-28 11:51:18 -070091config READABLE_ASM
92 bool "Generate readable assembler code"
93 depends on DEBUG_KERNEL
94 help
95 Disable some compiler optimizations that tend to generate human unreadable
96 assembler output. This may make the kernel slightly slower, but it helps
97 to keep kernel developers who have to stare a lot at assembler listings
98 sane.
99
Arjan van de Venf71d20e2006-06-28 04:26:45 -0700100config UNUSED_SYMBOLS
101 bool "Enable unused/obsolete exported symbols"
102 default y if X86
103 help
104 Unused but exported symbols make the kernel needlessly bigger. For
105 that reason most of these unused exports will soon be removed. This
106 option is provided temporarily to provide a transition period in case
107 some external kernel module needs one of these symbols anyway. If you
108 encounter such a case in your module, consider if you are actually
109 using the right API. (rationale: since nobody in the kernel is using
110 this in a module, there is a pretty good chance it's actually the
111 wrong interface to use). If you really need the symbol, please send a
112 mail to the linux kernel mailing list mentioning the symbol and why
113 you really need it, and what the merge plan to the mainline kernel for
114 your module is.
115
Don Mullisbf4735a2006-12-10 02:18:37 -0800116config DEBUG_FS
117 bool "Debug Filesystem"
Don Mullisbf4735a2006-12-10 02:18:37 -0800118 help
119 debugfs is a virtual file system that kernel developers use to put
120 debugging files into. Enable this option to be able to read and
121 write to these files.
122
Robert P. J. Dayff543332008-05-20 00:06:00 +0200123 For detailed documentation on the debugfs API, see
124 Documentation/DocBook/filesystems.
125
Don Mullisbf4735a2006-12-10 02:18:37 -0800126 If unsure, say N.
127
128config HEADERS_CHECK
129 bool "Run 'make headers_check' when building vmlinux"
130 depends on !UML
131 help
132 This option will extract the user-visible kernel headers whenever
133 building the kernel, and will run basic sanity checks on them to
134 ensure that exported files do not attempt to include files which
135 were not exported, etc.
136
137 If you're making modifications to header files which are
138 relevant for userspace, say 'Y', and check the headers
139 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
140 your build tree), to make sure they're suitable.
141
Sam Ravnborg91341d42008-01-21 21:31:44 +0100142config DEBUG_SECTION_MISMATCH
143 bool "Enable full Section mismatch analysis"
Sam Ravnborg91341d42008-01-21 21:31:44 +0100144 help
145 The section mismatch analysis checks if there are illegal
146 references from one section to another section.
Michael Wittene809ab02011-04-17 04:08:48 +0000147 During linktime or runtime, some sections are dropped;
148 any use of code/data previously in these sections would
Sam Ravnborg91341d42008-01-21 21:31:44 +0100149 most likely result in an oops.
Michael Wittene809ab02011-04-17 04:08:48 +0000150 In the code, functions and variables are annotated with
Greg Kroah-Hartman6ae14172012-12-21 15:16:45 -0800151 __init, __cpuinit, etc. (see the full list in include/linux/init.h),
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100152 which results in the code/data being placed in specific sections.
Michael Wittene809ab02011-04-17 04:08:48 +0000153 The section mismatch analysis is always performed after a full
154 kernel build, and enabling this option causes the following
155 additional steps to occur:
156 - Add the option -fno-inline-functions-called-once to gcc commands.
157 When inlining a function annotated with __init in a non-init
158 function, we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100159 the analysis would not catch the illegal reference.
Michael Wittene809ab02011-04-17 04:08:48 +0000160 This option tells gcc to inline less (but it does result in
161 a larger kernel).
162 - Run the section mismatch analysis for each module/built-in.o file.
163 When we run the section mismatch analysis on vmlinux.o, we
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100164 lose valueble information about where the mismatch was
Sam Ravnborg91341d42008-01-21 21:31:44 +0100165 introduced.
166 Running the analysis for each module/built-in.o file
Michael Wittene809ab02011-04-17 04:08:48 +0000167 tells where the mismatch happens much closer to the
168 source. The drawback is that the same mismatch is
169 reported at least twice.
170 - Enable verbose reporting from modpost in order to help resolve
171 the section mismatches that are reported.
Sam Ravnborg91341d42008-01-21 21:31:44 +0100172
Dave Hansen6dfc0662013-07-01 13:04:46 -0700173#
174# Select this config option from the architecture Kconfig, if it
175# is preferred to always offer frame pointers as a config
176# option on the architecture (regardless of KERNEL_DEBUG):
177#
178config ARCH_WANT_FRAME_POINTERS
179 bool
180 help
181
182config FRAME_POINTER
183 bool "Compile the kernel with frame pointers"
184 depends on DEBUG_KERNEL && \
185 (CRIS || M68K || FRV || UML || \
186 AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \
187 ARCH_WANT_FRAME_POINTERS
188 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
189 help
190 If you say Y here the resulting kernel image will be slightly
191 larger and slower, but it gives very useful debugging information
192 in case of kernel bugs. (precise oopses/stacktraces/warnings)
193
194config DEBUG_FORCE_WEAK_PER_CPU
195 bool "Force weak per-cpu definitions"
196 depends on DEBUG_KERNEL
197 help
198 s390 and alpha require percpu variables in modules to be
199 defined weak to work around addressing range issue which
200 puts the following two restrictions on percpu variable
201 definitions.
202
203 1. percpu symbols must be unique whether static or not
204 2. percpu variables can't be defined inside a function
205
206 To ensure that generic code follows the above rules, this
207 option forces all percpu variables to be defined as weak.
208
209endmenu # "Compiler options"
210
211config MAGIC_SYSRQ
212 bool "Magic SysRq key"
213 depends on !UML
214 help
215 If you say Y here, you will have some control over the system even
216 if the system crashes for example during kernel debugging (e.g., you
217 will be able to flush the buffer cache to disk, reboot the system
218 immediately or dump some status information). This is accomplished
219 by pressing various keys while holding SysRq (Alt+PrintScreen). It
220 also works on a serial console (on PC hardware at least), if you
221 send a BREAK and then within 5 seconds a command keypress. The
222 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
223 unless you really know what this hack does.
224
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800225config DEBUG_KERNEL
226 bool "Kernel debugging"
227 help
228 Say Y here if you are developing drivers or trying to debug and
229 identify kernel problems.
230
Dave Hansen0610c8a2013-07-01 13:04:43 -0700231menu "Memory Debugging"
232
233source mm/Kconfig.debug
234
235config DEBUG_OBJECTS
236 bool "Debug object operations"
237 depends on DEBUG_KERNEL
238 help
239 If you say Y here, additional code will be inserted into the
240 kernel to track the life time of various objects and validate
241 the operations on those objects.
242
243config DEBUG_OBJECTS_SELFTEST
244 bool "Debug objects selftest"
245 depends on DEBUG_OBJECTS
246 help
247 This enables the selftest of the object debug code.
248
249config DEBUG_OBJECTS_FREE
250 bool "Debug objects in freed memory"
251 depends on DEBUG_OBJECTS
252 help
253 This enables checks whether a k/v free operation frees an area
254 which contains an object which has not been deactivated
255 properly. This can make kmalloc/kfree-intensive workloads
256 much slower.
257
258config DEBUG_OBJECTS_TIMERS
259 bool "Debug timer objects"
260 depends on DEBUG_OBJECTS
261 help
262 If you say Y here, additional code will be inserted into the
263 timer routines to track the life time of timer objects and
264 validate the timer operations.
265
266config DEBUG_OBJECTS_WORK
267 bool "Debug work objects"
268 depends on DEBUG_OBJECTS
269 help
270 If you say Y here, additional code will be inserted into the
271 work queue routines to track the life time of work objects and
272 validate the work operations.
273
274config DEBUG_OBJECTS_RCU_HEAD
275 bool "Debug RCU callbacks objects"
276 depends on DEBUG_OBJECTS
277 help
278 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
279
280config DEBUG_OBJECTS_PERCPU_COUNTER
281 bool "Debug percpu counter objects"
282 depends on DEBUG_OBJECTS
283 help
284 If you say Y here, additional code will be inserted into the
285 percpu counter routines to track the life time of percpu counter
286 objects and validate the percpu counter operations.
287
288config DEBUG_OBJECTS_ENABLE_DEFAULT
289 int "debug_objects bootup default value (0-1)"
290 range 0 1
291 default "1"
292 depends on DEBUG_OBJECTS
293 help
294 Debug objects boot parameter default value
295
296config DEBUG_SLAB
297 bool "Debug slab memory allocations"
298 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
299 help
300 Say Y here to have the kernel do limited verification on memory
301 allocation as well as poisoning memory on free to catch use of freed
302 memory. This can make kmalloc/kfree-intensive workloads much slower.
303
304config DEBUG_SLAB_LEAK
305 bool "Memory leak debugging"
306 depends on DEBUG_SLAB
307
308config SLUB_DEBUG_ON
309 bool "SLUB debugging on by default"
310 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
311 default n
312 help
313 Boot with debugging on by default. SLUB boots by default with
314 the runtime debug capabilities switched off. Enabling this is
315 equivalent to specifying the "slub_debug" parameter on boot.
316 There is no support for more fine grained debug control like
317 possible with slub_debug=xxx. SLUB debugging may be switched
318 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
319 "slub_debug=-".
320
321config SLUB_STATS
322 default n
323 bool "Enable SLUB performance statistics"
324 depends on SLUB && SYSFS
325 help
326 SLUB statistics are useful to debug SLUBs allocation behavior in
327 order find ways to optimize the allocator. This should never be
328 enabled for production use since keeping statistics slows down
329 the allocator by a few percentage points. The slabinfo command
330 supports the determination of the most active slabs to figure
331 out which slabs are relevant to a particular load.
332 Try running: slabinfo -DA
333
334config HAVE_DEBUG_KMEMLEAK
335 bool
336
337config DEBUG_KMEMLEAK
338 bool "Kernel memory leak detector"
339 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
340 select DEBUG_FS
341 select STACKTRACE if STACKTRACE_SUPPORT
342 select KALLSYMS
343 select CRC32
344 help
345 Say Y here if you want to enable the memory leak
346 detector. The memory allocation/freeing is traced in a way
347 similar to the Boehm's conservative garbage collector, the
348 difference being that the orphan objects are not freed but
349 only shown in /sys/kernel/debug/kmemleak. Enabling this
350 feature will introduce an overhead to memory
351 allocations. See Documentation/kmemleak.txt for more
352 details.
353
354 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
355 of finding leaks due to the slab objects poisoning.
356
357 In order to access the kmemleak file, debugfs needs to be
358 mounted (usually at /sys/kernel/debug).
359
360config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
361 int "Maximum kmemleak early log entries"
362 depends on DEBUG_KMEMLEAK
363 range 200 40000
364 default 400
365 help
366 Kmemleak must track all the memory allocations to avoid
367 reporting false positives. Since memory may be allocated or
368 freed before kmemleak is initialised, an early log buffer is
369 used to store these actions. If kmemleak reports "early log
370 buffer exceeded", please increase this value.
371
372config DEBUG_KMEMLEAK_TEST
373 tristate "Simple test for the kernel memory leak detector"
374 depends on DEBUG_KMEMLEAK && m
375 help
376 This option enables a module that explicitly leaks memory.
377
378 If unsure, say N.
379
380config DEBUG_KMEMLEAK_DEFAULT_OFF
381 bool "Default kmemleak to off"
382 depends on DEBUG_KMEMLEAK
383 help
384 Say Y here to disable kmemleak by default. It can then be enabled
385 on the command line via kmemleak=on.
386
387config DEBUG_STACK_USAGE
388 bool "Stack utilization instrumentation"
389 depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG
390 help
391 Enables the display of the minimum amount of free stack which each
392 task has ever had available in the sysrq-T and sysrq-P debug output.
393
394 This option will slow down process creation somewhat.
395
396config DEBUG_VM
397 bool "Debug VM"
398 depends on DEBUG_KERNEL
399 help
400 Enable this to turn on extended checks in the virtual-memory system
401 that may impact performance.
402
403 If unsure, say N.
404
405config DEBUG_VM_RB
406 bool "Debug VM red-black trees"
407 depends on DEBUG_VM
408 help
409 Enable this to turn on more extended checks in the virtual-memory
410 system that may impact performance.
411
412 If unsure, say N.
413
414config DEBUG_VIRTUAL
415 bool "Debug VM translations"
416 depends on DEBUG_KERNEL && X86
417 help
418 Enable some costly sanity checks in virtual to page code. This can
419 catch mistakes with virt_to_page() and friends.
420
421 If unsure, say N.
422
423config DEBUG_NOMMU_REGIONS
424 bool "Debug the global anon/private NOMMU mapping region tree"
425 depends on DEBUG_KERNEL && !MMU
426 help
427 This option causes the global tree of anonymous and private mapping
428 regions to be regularly checked for invalid topology.
429
430config DEBUG_MEMORY_INIT
431 bool "Debug memory initialisation" if EXPERT
432 default !EXPERT
433 help
434 Enable this for additional checks during memory initialisation.
435 The sanity checks verify aspects of the VM such as the memory model
436 and other information provided by the architecture. Verbose
437 information will be printed at KERN_DEBUG loglevel depending
438 on the mminit_loglevel= command-line option.
439
440 If unsure, say Y
441
442config MEMORY_NOTIFIER_ERROR_INJECT
443 tristate "Memory hotplug notifier error injection module"
444 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
445 help
446 This option provides the ability to inject artificial errors to
447 memory hotplug notifier chain callbacks. It is controlled through
448 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
449
450 If the notifier call chain should be failed with some events
451 notified, write the error code to "actions/<notifier event>/error".
452
453 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
454
455 # cd /sys/kernel/debug/notifier-error-inject/memory
456 # echo -12 > actions/MEM_GOING_OFFLINE/error
457 # echo offline > /sys/devices/system/memory/memoryXXX/state
458 bash: echo: write error: Cannot allocate memory
459
460 To compile this code as a module, choose M here: the module will
461 be called memory-notifier-error-inject.
462
463 If unsure, say N.
464
465config DEBUG_PER_CPU_MAPS
466 bool "Debug access to per_cpu maps"
467 depends on DEBUG_KERNEL
468 depends on SMP
469 help
470 Say Y to verify that the per_cpu map being accessed has
471 been set up. This adds a fair amount of code to kernel memory
472 and decreases performance.
473
474 Say N if unsure.
475
476config DEBUG_HIGHMEM
477 bool "Highmem debugging"
478 depends on DEBUG_KERNEL && HIGHMEM
479 help
480 This options enables addition error checking for high memory systems.
481 Disable for production systems.
482
483config HAVE_DEBUG_STACKOVERFLOW
484 bool
485
486config DEBUG_STACKOVERFLOW
487 bool "Check for stack overflows"
488 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
489 ---help---
490 Say Y here if you want to check for overflows of kernel, IRQ
491 and exception stacks (if your archicture uses them). This
492 option will show detailed messages if free stack space drops
493 below a certain limit.
494
495 These kinds of bugs usually occur when call-chains in the
496 kernel get too deep, especially when interrupts are
497 involved.
498
499 Use this in cases where you see apparently random memory
500 corruption, especially if it appears in 'struct thread_info'
501
502 If in doubt, say "N".
503
504source "lib/Kconfig.kmemcheck"
505
506endmenu # "Memory Debugging"
507
David Woodhousea304e1b2007-02-12 00:52:00 -0800508config DEBUG_SHIRQ
509 bool "Debug shared IRQ handlers"
510 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
511 help
512 Enable this to generate a spurious interrupt as soon as a shared
513 interrupt handler is registered, and just before one is deregistered.
514 Drivers ought to be able to handle interrupts coming in at those
515 points; some don't and need to be caught.
516
Don Zickus58687ac2010-05-07 17:11:44 -0400517config LOCKUP_DETECTOR
518 bool "Detect Hard and Soft Lockups"
Heiko Carstensdea20a32006-10-11 01:20:44 -0700519 depends on DEBUG_KERNEL && !S390
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700520 help
Don Zickus58687ac2010-05-07 17:11:44 -0400521 Say Y here to enable the kernel to act as a watchdog to detect
522 hard and soft lockups.
Don Zickus84e478c2010-02-05 21:47:05 -0500523
Don Zickus58687ac2010-05-07 17:11:44 -0400524 Softlockups are bugs that cause the kernel to loop in kernel
Fernando Luis Vázquez Cao5f329082012-02-09 17:42:21 -0500525 mode for more than 20 seconds, without giving other tasks a
Don Zickus58687ac2010-05-07 17:11:44 -0400526 chance to run. The current stack trace is displayed upon
527 detection and the system will stay locked up.
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700528
Don Zickus58687ac2010-05-07 17:11:44 -0400529 Hardlockups are bugs that cause the CPU to loop in kernel mode
Fernando Luis Vázquez Cao5f329082012-02-09 17:42:21 -0500530 for more than 10 seconds, without letting other interrupts have a
Don Zickus58687ac2010-05-07 17:11:44 -0400531 chance to run. The current stack trace is displayed upon detection
532 and the system will stay locked up.
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700533
Don Zickus58687ac2010-05-07 17:11:44 -0400534 The overhead should be minimal. A periodic hrtimer runs to
Fernando Luis Vázquez Cao5f329082012-02-09 17:42:21 -0500535 generate interrupts and kick the watchdog task every 4 seconds.
536 An NMI is generated every 10 seconds or so to check for hardlockups.
537
538 The frequency of hrtimer and NMI events and the soft and hard lockup
539 thresholds can be controlled through the sysctl watchdog_thresh.
Don Zickus84e478c2010-02-05 21:47:05 -0500540
Frederic Weisbecker23637d42010-05-15 23:15:20 +0200541config HARDLOCKUP_DETECTOR
Jan Beulich8f1f66e2012-10-04 17:13:17 -0700542 def_bool y
543 depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG
544 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700545
Don Zickusfef2c9b2011-03-22 16:34:16 -0700546config BOOTPARAM_HARDLOCKUP_PANIC
547 bool "Panic (Reboot) On Hard Lockups"
Jan Beulich8f1f66e2012-10-04 17:13:17 -0700548 depends on HARDLOCKUP_DETECTOR
Don Zickusfef2c9b2011-03-22 16:34:16 -0700549 help
550 Say Y here to enable the kernel to panic on "hard lockups",
551 which are bugs that cause the kernel to loop in kernel
Fernando Luis Vázquez Cao5f329082012-02-09 17:42:21 -0500552 mode with interrupts disabled for more than 10 seconds (configurable
553 using the watchdog_thresh sysctl).
Don Zickusfef2c9b2011-03-22 16:34:16 -0700554
555 Say N if unsure.
556
557config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
558 int
Jan Beulich8f1f66e2012-10-04 17:13:17 -0700559 depends on HARDLOCKUP_DETECTOR
Don Zickusfef2c9b2011-03-22 16:34:16 -0700560 range 0 1
561 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
562 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
563
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200564config BOOTPARAM_SOFTLOCKUP_PANIC
565 bool "Panic (Reboot) On Soft Lockups"
Frederic Weisbecker89d7ce22010-05-13 00:27:20 +0200566 depends on LOCKUP_DETECTOR
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200567 help
568 Say Y here to enable the kernel to panic on "soft lockups",
569 which are bugs that cause the kernel to loop in kernel
Fernando Luis Vázquez Cao5f329082012-02-09 17:42:21 -0500570 mode for more than 20 seconds (configurable using the watchdog_thresh
571 sysctl), without giving other tasks a chance to run.
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200572
573 The panic can be used in combination with panic_timeout,
574 to cause the system to reboot automatically after a
575 lockup has been detected. This feature is useful for
576 high-availability systems that have uptime guarantees and
577 where a lockup must be resolved ASAP.
578
579 Say N if unsure.
580
581config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
582 int
Frederic Weisbeckere16bb1d2010-05-15 22:30:22 +0200583 depends on LOCKUP_DETECTOR
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200584 range 0 1
585 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
586 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
587
Kyle McMartin2a01bb32012-04-11 08:15:29 -0400588config PANIC_ON_OOPS
Kyle McMartin76e84022013-02-21 16:43:04 -0800589 bool "Panic on Oops"
Kyle McMartin2a01bb32012-04-11 08:15:29 -0400590 help
591 Say Y here to enable the kernel to panic when it oopses. This
592 has the same effect as setting oops=panic on the kernel command
593 line.
594
595 This feature is useful to ensure that the kernel does not do
596 anything erroneous after an oops which could result in data
597 corruption or other issues.
598
599 Say N if unsure.
600
601config PANIC_ON_OOPS_VALUE
602 int
603 range 0 1
604 default 0 if !PANIC_ON_OOPS
605 default 1 if PANIC_ON_OOPS
606
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800607config DETECT_HUNG_TASK
608 bool "Detect Hung Tasks"
609 depends on DEBUG_KERNEL
Anton Blanchard8edbb832011-07-05 13:32:40 +1000610 default LOCKUP_DETECTOR
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800611 help
612 Say Y here to enable the kernel to detect "hung tasks",
613 which are bugs that cause the task to be stuck in
614 uninterruptible "D" state indefinitiley.
615
616 When a hung task is detected, the kernel will print the
617 current stack trace (which you should report), but the
618 task will stay in uninterruptible state. If lockdep is
619 enabled then all held locks will also be reported. This
620 feature has negligible overhead.
621
Jeff Mahoneye11feaa2011-04-27 14:27:24 -0400622config DEFAULT_HUNG_TASK_TIMEOUT
623 int "Default timeout for hung task detection (in seconds)"
624 depends on DETECT_HUNG_TASK
625 default 120
626 help
627 This option controls the default timeout (in seconds) used
628 to determine when a task has become non-responsive and should
629 be considered hung.
630
Jiaju Zhangc51eaac2011-10-31 17:10:07 -0700631 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
632 sysctl or by writing a value to
633 /proc/sys/kernel/hung_task_timeout_secs.
Jeff Mahoneye11feaa2011-04-27 14:27:24 -0400634
635 A timeout of 0 disables the check. The default is two minutes.
636 Keeping the default should be fine in most cases.
637
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800638config BOOTPARAM_HUNG_TASK_PANIC
639 bool "Panic (Reboot) On Hung Tasks"
640 depends on DETECT_HUNG_TASK
641 help
642 Say Y here to enable the kernel to panic on "hung tasks",
643 which are bugs that cause the kernel to leave a task stuck
644 in uninterruptible "D" state.
645
646 The panic can be used in combination with panic_timeout,
647 to cause the system to reboot automatically after a
648 hung task has been detected. This feature is useful for
649 high-availability systems that have uptime guarantees and
650 where a hung tasks must be resolved ASAP.
651
652 Say N if unsure.
653
654config BOOTPARAM_HUNG_TASK_PANIC_VALUE
655 int
656 depends on DETECT_HUNG_TASK
657 range 0 1
658 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
659 default 1 if BOOTPARAM_HUNG_TASK_PANIC
660
Ingo Molnarb642b6d2007-07-09 18:52:00 +0200661config SCHED_DEBUG
662 bool "Collect scheduler debugging info"
663 depends on DEBUG_KERNEL && PROC_FS
664 default y
665 help
666 If you say Y here, the /proc/sched_debug file will be provided
667 that can help debug the scheduler. The runtime overhead of this
668 option is minimal.
669
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670config SCHEDSTATS
671 bool "Collect scheduler statistics"
672 depends on DEBUG_KERNEL && PROC_FS
673 help
674 If you say Y here, additional code will be inserted into the
675 scheduler and related routines to collect statistics about
676 scheduler behavior and provide them in /proc/schedstat. These
677 stats may be useful for both tuning and debugging the scheduler
678 If you aren't debugging the scheduler or trying to tune a specific
679 application, you can say N to avoid the very slight overhead
680 this adds.
681
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800682config TIMER_STATS
683 bool "Collect kernel timers statistics"
684 depends on DEBUG_KERNEL && PROC_FS
685 help
686 If you say Y here, additional code will be inserted into the
687 timer routines to collect statistics about kernel timers being
688 reprogrammed. The statistics can be read from /proc/timer_stats.
689 The statistics collection is started by writing 1 to /proc/timer_stats,
690 writing 0 stops it. This feature is useful to collect information
Ingo Molnarc1a834d2007-06-01 00:47:16 -0700691 about timer usage patterns in kernel and userspace. This feature
692 is lightweight if enabled in the kernel config but not activated
693 (it defaults to deactivated on bootup and will only be activated
694 if some application like powertop activates it explicitly).
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800695
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696config DEBUG_PREEMPT
697 bool "Debug preemptible kernel"
Kumar Gala01deab92009-10-16 07:21:39 +0000698 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 default y
700 help
701 If you say Y here then the kernel will use a debug variant of the
702 commonly used smp_processor_id() function and will print warnings
703 if kernel code uses it in a preemption-unsafe way. Also, the kernel
704 will detect preemption count underflows.
705
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700706config DEBUG_RT_MUTEXES
707 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700708 depends on DEBUG_KERNEL && RT_MUTEXES
709 help
710 This allows rt mutex semantics violations and rt mutex related
711 deadlocks (lockups) to be detected and reported automatically.
712
713config DEBUG_PI_LIST
714 bool
715 default y
716 depends on DEBUG_RT_MUTEXES
717
Thomas Gleixner61a87122006-06-27 02:54:56 -0700718config RT_MUTEX_TESTER
719 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700720 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700721 help
722 This option enables a rt-mutex tester.
723
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700725 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +0530727 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 help
729 Say Y here and build SMP to catch missing spinlock initialization
730 and certain other kinds of spinlock errors commonly made. This is
731 best used in conjunction with the NMI watchdog so that spinlock
732 deadlocks are also debuggable.
733
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700734config DEBUG_MUTEXES
735 bool "Mutex debugging: basic checks"
736 depends on DEBUG_KERNEL
737 help
738 This feature allows mutex semantics violations to be detected and
739 reported.
740
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700741config DEBUG_LOCK_ALLOC
742 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700743 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700744 select DEBUG_SPINLOCK
745 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700746 select LOCKDEP
747 help
748 This feature will check whether any held lock (spinlock, rwlock,
749 mutex or rwsem) is incorrectly freed by the kernel, via any of the
750 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
751 vfree(), etc.), whether a live lock is incorrectly reinitialized via
752 spin_lock_init()/mutex_init()/etc., or whether there is any lock
753 held during task exit.
754
755config PROVE_LOCKING
756 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700757 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700758 select LOCKDEP
759 select DEBUG_SPINLOCK
760 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700761 select DEBUG_LOCK_ALLOC
Steven Rostedt46b93b72010-08-31 16:35:20 -0400762 select TRACE_IRQFLAGS
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700763 default n
764 help
765 This feature enables the kernel to prove that all locking
766 that occurs in the kernel runtime is mathematically
767 correct: that under no circumstance could an arbitrary (and
768 not yet triggered) combination of observed locking
769 sequences (on an arbitrary number of CPUs, running an
770 arbitrary number of tasks and interrupt contexts) cause a
771 deadlock.
772
773 In short, this feature enables the kernel to report locking
774 related deadlocks before they actually occur.
775
776 The proof does not depend on how hard and complex a
777 deadlock scenario would be to trigger: how many
778 participant CPUs, tasks and irq-contexts would be needed
779 for it to trigger. The proof also does not depend on
780 timing: if a race and a resulting deadlock is possible
781 theoretically (no matter how unlikely the race scenario
782 is), it will be proven so and will immediately be
783 reported by the kernel (once the event is observed that
784 makes the deadlock theoretically possible).
785
786 If a deadlock is impossible (i.e. the locking rules, as
787 observed by the kernel, are mathematically correct), the
788 kernel reports nothing.
789
790 NOTE: this feature can also be enabled for rwlocks, mutexes
791 and rwsems - in which case all dependencies between these
792 different locking variants are observed and mapped too, and
793 the proof of observed correctness is also maintained for an
794 arbitrary combination of these separate locking variants.
795
796 For more details, see Documentation/lockdep-design.txt.
797
798config LOCKDEP
799 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700800 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700801 select STACKTRACE
Michal Simek79aac882010-05-25 11:33:26 +0200802 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700803 select KALLSYMS
804 select KALLSYMS_ALL
805
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700806config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700807 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700808 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
809 select LOCKDEP
810 select DEBUG_SPINLOCK
811 select DEBUG_MUTEXES
812 select DEBUG_LOCK_ALLOC
813 default n
814 help
815 This feature enables tracking lock contention points
816
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700817 For more details, see Documentation/lockstat.txt
818
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +0100819 This also enables lock events required by "perf lock",
820 subcommand of perf.
821 If you want to use "perf lock", you also need to turn on
822 CONFIG_EVENT_TRACING.
Hitoshi Mitake84c6f882010-02-04 16:08:15 +0900823
824 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +0100825 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
Hitoshi Mitake84c6f882010-02-04 16:08:15 +0900826
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700827config DEBUG_LOCKDEP
828 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700829 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700830 help
831 If you say Y here, the lock dependency engine will do
832 additional runtime checks to debug itself, at the price
833 of more runtime overhead.
834
835config TRACE_IRQFLAGS
836 bool
Steven Rostedt46b93b72010-08-31 16:35:20 -0400837 help
838 Enables hooks to interrupt enabling and disabling for
839 either tracing or lock debugging.
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700840
Frederic Weisbeckerd902db12011-06-08 19:31:56 +0200841config DEBUG_ATOMIC_SLEEP
842 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +0200843 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 depends on DEBUG_KERNEL
845 help
846 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +0200847 noisy if they are called inside atomic sections: when a spinlock is
848 held, inside an rcu read side critical section, inside preempt disabled
849 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700851config DEBUG_LOCKING_API_SELFTESTS
852 bool "Locking API boot-time self-tests"
853 depends on DEBUG_KERNEL
854 help
855 Say Y here if you want the kernel to run a short self-test during
856 bootup. The self-test checks whether common types of locking bugs
857 are detected by debugging mechanisms or not. (if you disable
858 lock debugging then those bugs wont be detected of course.)
859 The following locking APIs are covered: spinlocks, rwlocks,
860 mutexes and rwsems.
861
Ingo Molnar8637c092006-07-03 00:24:38 -0700862config STACKTRACE
863 bool
864 depends on STACKTRACE_SUPPORT
865
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866config DEBUG_KOBJECT
867 bool "kobject debugging"
868 depends on DEBUG_KERNEL
869 help
870 If you say Y here, some extra kobject debugging messages will be sent
871 to the syslog.
872
Catalin Marinas9b2a60c2012-10-08 16:28:13 -0700873config HAVE_DEBUG_BUGVERBOSE
874 bool
875
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876config DEBUG_BUGVERBOSE
David Rientjes6a108a12011-01-20 14:44:16 -0800877 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
Catalin Marinas9b2a60c2012-10-08 16:28:13 -0700878 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
Alexey Dobriyan8420e7e2009-12-14 18:00:25 -0800879 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880 help
881 Say Y here to make BUG() panics output the file name and line number
882 of the BUG call as well as the EIP and oops trace. This aids
883 debugging but costs about 70-100K of memory.
884
Dave Hansenad775f52008-02-15 14:38:01 -0800885config DEBUG_WRITECOUNT
886 bool "Debug filesystem writers count"
887 depends on DEBUG_KERNEL
888 help
889 Enable this to catch wrong use of the writers count in struct
890 vfsmount. This will increase the size of each file struct by
891 32 bits.
892
893 If unsure, say N.
894
Dave Jones199a9af2006-09-29 01:59:00 -0700895config DEBUG_LIST
896 bool "Debug linked list manipulation"
897 depends on DEBUG_KERNEL
898 help
899 Enable this to turn on extended checks in the linked-list
900 walking routines.
901
902 If unsure, say N.
903
Jens Axboed6ec0842007-10-22 20:01:06 +0200904config DEBUG_SG
905 bool "Debug SG table operations"
906 depends on DEBUG_KERNEL
907 help
908 Enable this to turn on checks on scatter-gather tables. This can
909 help find problems with drivers that do not properly initialize
910 their sg tables.
911
912 If unsure, say N.
913
Arjan van de Ven1b2439d2008-08-15 15:29:38 -0700914config DEBUG_NOTIFIERS
915 bool "Debug notifier call chains"
916 depends on DEBUG_KERNEL
917 help
918 Enable this to turn on sanity checking for notifier call chains.
919 This is most useful for kernel developers to make sure that
920 modules properly unregister themselves from notifier chains.
921 This is a relatively cheap check but if you care about maximum
922 performance, say N.
923
David Howellse0e81732009-09-02 09:13:40 +0100924config DEBUG_CREDENTIALS
925 bool "Debug credential management"
926 depends on DEBUG_KERNEL
927 help
928 Enable this to turn on some debug checking for credential
929 management. The additional code keeps track of the number of
930 pointers from task_structs to any given cred struct, and checks to
931 see that this number never exceeds the usage count of the cred
932 struct.
933
934 Furthermore, if SELinux is enabled, this also checks that the
935 security pointer in the cred struct is never seen to be invalid.
936
937 If unsure, say N.
938
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700939config BOOT_PRINTK_DELAY
940 bool "Delay each boot printk message by N milliseconds"
941 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
942 help
943 This build option allows you to read kernel boot messages
944 by inserting a short delay after each one. The delay is
945 specified in milliseconds on the kernel command line,
946 using "boot_delay=N".
947
948 It is likely that you would also need to use "lpj=M" to preset
949 the "loops per jiffie" value.
950 See a previous boot log for the "lpj" value to use for your
951 system, and then set "lpj=M" before setting "boot_delay=N".
952 NOTE: Using this option may adversely affect SMP systems.
953 I.e., processors other than the first one may not boot up.
Anton Blanchard8edbb832011-07-05 13:32:40 +1000954 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700955 what it believes to be lockup conditions.
956
Dave Hansen2f03e3c2013-01-07 08:19:23 -0800957menu "RCU Debugging"
958
959config PROVE_RCU
960 bool "RCU debugging: prove RCU correctness"
961 depends on PROVE_LOCKING
962 default n
963 help
964 This feature enables lockdep extensions that check for correct
965 use of RCU APIs. This is currently under development. Say Y
966 if you want to debug RCU usage or help work on the PROVE_RCU
967 feature.
968
969 Say N if you are unsure.
970
971config PROVE_RCU_REPEATEDLY
972 bool "RCU debugging: don't disable PROVE_RCU on first splat"
973 depends on PROVE_RCU
974 default n
975 help
976 By itself, PROVE_RCU will disable checking upon issuing the
977 first warning (or "splat"). This feature prevents such
978 disabling, allowing multiple RCU-lockdep warnings to be printed
979 on a single reboot.
980
981 Say Y to allow multiple RCU-lockdep warnings per boot.
982
983 Say N if you are unsure.
984
985config PROVE_RCU_DELAY
986 bool "RCU debugging: preemptible RCU race provocation"
987 depends on DEBUG_KERNEL && PREEMPT_RCU
988 default n
989 help
990 There is a class of races that involve an unlikely preemption
991 of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
992 been set to INT_MIN. This feature inserts a delay at that
993 point to increase the probability of these races.
994
995 Say Y to increase probability of preemption of __rcu_read_unlock().
996
997 Say N if you are unsure.
998
999config SPARSE_RCU_POINTER
1000 bool "RCU debugging: sparse-based checks for pointer usage"
1001 default n
1002 help
1003 This feature enables the __rcu sparse annotation for
1004 RCU-protected pointers. This annotation will cause sparse
1005 to flag any non-RCU used of annotated pointers. This can be
1006 helpful when debugging RCU usage. Please note that this feature
1007 is not intended to enforce code cleanliness; it is instead merely
1008 a debugging aid.
1009
1010 Say Y to make sparse flag questionable use of RCU-protected pointers
1011
1012 Say N if you are unsure.
1013
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001014config RCU_TORTURE_TEST
1015 tristate "torture tests for RCU"
1016 depends on DEBUG_KERNEL
1017 default n
1018 help
1019 This option provides a kernel module that runs torture tests
1020 on the RCU infrastructure. The kernel module may be built
1021 after the fact on the running kernel to be tested, if desired.
1022
Paul E. McKenney31a72bc2008-06-18 09:26:49 -07001023 Say Y here if you want RCU torture tests to be built into
1024 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001025 Say M if you want the RCU torture tests to build as a module.
1026 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -07001027
Paul E. McKenney31a72bc2008-06-18 09:26:49 -07001028config RCU_TORTURE_TEST_RUNNABLE
1029 bool "torture tests for RCU runnable by default"
1030 depends on RCU_TORTURE_TEST = y
1031 default n
1032 help
1033 This option provides a way to build the RCU torture tests
1034 directly into the kernel without them starting up at boot
1035 time. You can use /proc/sys/kernel/rcutorture_runnable
1036 to manually override this setting. This /proc file is
1037 available only when the RCU torture tests have been built
1038 into the kernel.
1039
1040 Say Y here if you want the RCU torture tests to start during
1041 boot (you probably don't).
1042 Say N here if you want the RCU torture tests to start only
1043 after being manually enabled via /proc.
1044
Paul E. McKenneyb1637602010-06-02 16:21:38 -07001045config RCU_CPU_STALL_TIMEOUT
1046 int "RCU CPU stall timeout in seconds"
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -07001047 depends on RCU_STALL_COMMON
Paul E. McKenneyb1637602010-06-02 16:21:38 -07001048 range 3 300
Paul E. McKenneyc8960542012-10-25 17:59:23 -07001049 default 21
Paul E. McKenneyb1637602010-06-02 16:21:38 -07001050 help
1051 If a given RCU grace period extends more than the specified
1052 number of seconds, a CPU stall warning is printed. If the
1053 RCU grace period persists, additional CPU stall warnings are
1054 printed at more widely spaced intervals.
1055
Paul E. McKenney1ed509a2010-02-22 17:05:05 -08001056config RCU_CPU_STALL_VERBOSE
1057 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
Paul E. McKenneya00e0d712011-02-08 17:14:39 -08001058 depends on TREE_PREEMPT_RCU
Paul E. McKenney55ec9362010-04-13 12:22:33 -07001059 default y
Paul E. McKenney1ed509a2010-02-22 17:05:05 -08001060 help
1061 This option causes RCU to printk detailed per-task information
1062 for any tasks that are stalling the current RCU grace period.
Paul E. McKenney64db4cf2008-12-18 21:55:32 +01001063
1064 Say N if you are unsure.
1065
Paul E. McKenney1ed509a2010-02-22 17:05:05 -08001066 Say Y if you want to enable such checks.
1067
Paul E. McKenneya858af22012-01-16 13:29:10 -08001068config RCU_CPU_STALL_INFO
1069 bool "Print additional diagnostics on RCU CPU stall"
1070 depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
1071 default n
1072 help
1073 For each stalled CPU that is aware of the current RCU grace
1074 period, print out additional per-CPU diagnostic information
1075 regarding scheduling-clock ticks, idle state, and,
1076 for RCU_FAST_NO_HZ kernels, idle-entry state.
1077
1078 Say N if you are unsure.
1079
1080 Say Y if you want to enable such diagnostics.
1081
Paul E. McKenney5c8806a2012-01-06 15:10:44 -08001082config RCU_TRACE
1083 bool "Enable tracing for RCU"
1084 depends on DEBUG_KERNEL
Paul E. McKenney52494532012-11-14 16:26:40 -08001085 select TRACE_CLOCK
Paul E. McKenney5c8806a2012-01-06 15:10:44 -08001086 help
1087 This option provides tracing in RCU which presents stats
1088 in debugfs for debugging RCU implementation.
1089
1090 Say Y here if you want to enable RCU tracing
1091 Say N if you are unsure.
1092
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001093endmenu # "RCU Debugging"
1094
Tejun Heo870d6652008-08-25 19:47:25 +09001095config DEBUG_BLOCK_EXT_DEVT
1096 bool "Force extended block device numbers and spread them"
1097 depends on DEBUG_KERNEL
1098 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +02001099 default n
Tejun Heo870d6652008-08-25 19:47:25 +09001100 help
Tejun Heo0e11e342008-10-13 10:46:01 +02001101 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1102 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1103 YOU ARE DOING. Distros, please enable this and fix whatever
1104 is broken.
1105
Tejun Heo870d6652008-08-25 19:47:25 +09001106 Conventionally, block device numbers are allocated from
1107 predetermined contiguous area. However, extended block area
1108 may introduce non-contiguous block device numbers. This
1109 option forces most block device numbers to be allocated from
1110 the extended space and spreads them to discover kernel or
1111 userland code paths which assume predetermined contiguous
1112 device number allocation.
1113
Tejun Heo55dc7db2008-09-01 13:44:35 +02001114 Note that turning on this debug option shuffles all the
1115 device numbers for all IDE and SCSI devices including libata
1116 ones, so root partition specified using device number
1117 directly (via rdev or root=MAJ:MIN) won't work anymore.
1118 Textual device names (root=/dev/sdXn) will continue to work.
1119
Tejun Heo870d6652008-08-25 19:47:25 +09001120 Say N if you are unsure.
1121
Akinobu Mita8d438282012-07-30 14:43:02 -07001122config NOTIFIER_ERROR_INJECTION
1123 tristate "Notifier error injection"
1124 depends on DEBUG_KERNEL
1125 select DEBUG_FS
1126 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001127 This option provides the ability to inject artificial errors to
Akinobu Mita8d438282012-07-30 14:43:02 -07001128 specified notifier chain callbacks. It is useful to test the error
1129 handling of notifier call chain failures.
1130
1131 Say N if unsure.
1132
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001133config CPU_NOTIFIER_ERROR_INJECT
1134 tristate "CPU notifier error injection module"
Akinobu Mitaf5a9f522012-07-30 14:43:03 -07001135 depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001136 help
1137 This option provides a kernel module that can be used to test
Masanari Iidae41e85c2012-11-30 16:44:39 +09001138 the error handling of the cpu notifiers by injecting artificial
Akinobu Mitaf5a9f522012-07-30 14:43:03 -07001139 errors to CPU notifier chain callbacks. It is controlled through
1140 debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu
1141
1142 If the notifier call chain should be failed with some events
1143 notified, write the error code to "actions/<notifier event>/error".
1144
1145 Example: Inject CPU offline error (-1 == -EPERM)
1146
1147 # cd /sys/kernel/debug/notifier-error-inject/cpu
1148 # echo -1 > actions/CPU_DOWN_PREPARE/error
1149 # echo 0 > /sys/devices/system/cpu/cpu1/online
1150 bash: echo: write error: Operation not permitted
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001151
1152 To compile this code as a module, choose M here: the module will
1153 be called cpu-notifier-error-inject.
1154
1155 If unsure, say N.
1156
Akinobu Mita048b9c352012-07-30 14:43:07 -07001157config PM_NOTIFIER_ERROR_INJECT
1158 tristate "PM notifier error injection module"
1159 depends on PM && NOTIFIER_ERROR_INJECTION
1160 default m if PM_DEBUG
1161 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001162 This option provides the ability to inject artificial errors to
Akinobu Mita048b9c352012-07-30 14:43:07 -07001163 PM notifier chain callbacks. It is controlled through debugfs
1164 interface /sys/kernel/debug/notifier-error-inject/pm
1165
1166 If the notifier call chain should be failed with some events
1167 notified, write the error code to "actions/<notifier event>/error".
1168
1169 Example: Inject PM suspend error (-12 = -ENOMEM)
1170
1171 # cd /sys/kernel/debug/notifier-error-inject/pm/
1172 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1173 # echo mem > /sys/power/state
1174 bash: echo: write error: Cannot allocate memory
1175
1176 To compile this code as a module, choose M here: the module will
1177 be called pm-notifier-error-inject.
1178
1179 If unsure, say N.
1180
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001181config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1182 tristate "OF reconfig notifier error injection module"
1183 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001184 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001185 This option provides the ability to inject artificial errors to
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001186 OF reconfig notifier chain callbacks. It is controlled
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001187 through debugfs interface under
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001188 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001189
1190 If the notifier call chain should be failed with some events
1191 notified, write the error code to "actions/<notifier event>/error".
1192
1193 To compile this code as a module, choose M here: the module will
Akinobu Mitae12a95f2013-04-30 15:28:49 -07001194 be called of-reconfig-notifier-error-inject.
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001195
1196 If unsure, say N.
1197
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001198config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001199 bool "Fault-injection framework"
1200 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001201 help
1202 Provide fault-injection framework.
1203 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001204
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001205config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001206 bool "Fault-injection capability for kmalloc"
1207 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001208 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001209 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001210 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001211
Akinobu Mita933e3122006-12-08 02:39:45 -08001212config FAIL_PAGE_ALLOC
1213 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001214 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001215 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001216 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001217
Akinobu Mitac17bb492006-12-08 02:39:46 -08001218config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001219 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001220 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001221 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001222 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001223
Jens Axboe581d4e22008-09-14 05:56:33 -07001224config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d01432010-07-21 16:05:53 +09001225 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001226 depends on FAULT_INJECTION && BLOCK
1227 help
1228 Provide fault-injection capability on end IO handling. This
1229 will make the block layer "forget" an interrupt as configured,
1230 thus exercising the error handling.
1231
1232 Only works with drivers that use the generic timeout handling,
1233 for others it wont do anything.
1234
Per Forlin1b676f72011-08-19 14:52:37 +02001235config FAIL_MMC_REQUEST
1236 bool "Fault-injection capability for MMC IO"
1237 select DEBUG_FS
1238 depends on FAULT_INJECTION && MMC
1239 help
1240 Provide fault-injection capability for MMC IO.
1241 This will make the mmc core return data errors. This is
1242 useful to test the error handling in the mmc block device
1243 and to test how the mmc host driver handles retries from
1244 the block device.
1245
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001246config FAULT_INJECTION_DEBUG_FS
1247 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001248 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001249 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001250 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -08001251
1252config FAULT_INJECTION_STACKTRACE_FILTER
1253 bool "stacktrace filter for fault-injection capabilities"
1254 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001255 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001256 select STACKTRACE
Arnd Bergmann89bace62011-06-10 14:12:21 +00001257 select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
Akinobu Mita1df49002007-02-20 13:57:56 -08001258 help
1259 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001260
Arjan van de Ven97455122008-01-25 21:08:34 +01001261config LATENCYTOP
1262 bool "Latency measuring infrastructure"
Randy Dunlap625fdca2010-08-12 12:31:21 -07001263 depends on HAVE_LATENCYTOP_SUPPORT
1264 depends on DEBUG_KERNEL
1265 depends on STACKTRACE_SUPPORT
1266 depends on PROC_FS
Arnd Bergmann89bace62011-06-10 14:12:21 +00001267 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
Arjan van de Ven97455122008-01-25 21:08:34 +01001268 select KALLSYMS
1269 select KALLSYMS_ALL
1270 select STACKTRACE
1271 select SCHEDSTATS
1272 select SCHED_DEBUG
Arjan van de Ven97455122008-01-25 21:08:34 +01001273 help
1274 Enable this option if you want to use the LatencyTOP tool
1275 to find out which userspace is blocking on what kernel operations.
1276
Stephen Boyd446f24d2013-04-30 15:28:42 -07001277config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1278 bool
1279
1280config DEBUG_STRICT_USER_COPY_CHECKS
1281 bool "Strict user copy size checks"
1282 depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1283 depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING
1284 help
1285 Enabling this option turns a certain set of sanity checks for user
1286 copy operations into compile time failures.
1287
1288 The copy_from_user() etc checks are there to help test if there
1289 are sufficient security checks on the length argument of
1290 the copy operation, by having gcc prove that the argument is
1291 within bounds.
1292
1293 If unsure, say N.
1294
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001295source kernel/trace/Kconfig
1296
Dave Hansen881c5142013-07-01 13:04:44 -07001297menu "Runtime Testing"
1298
1299config LKDTM
1300 tristate "Linux Kernel Dump Test Tool Module"
1301 depends on DEBUG_FS
1302 depends on BLOCK
1303 default n
1304 help
1305 This module enables testing of the different dumping mechanisms by
1306 inducing system failures at predefined crash points.
1307 If you don't need it: say N
1308 Choose M here to compile this code as a module. The module will be
1309 called lkdtm.
1310
1311 Documentation on how to use the module can be found in
1312 Documentation/fault-injection/provoke-crashes.txt
1313
1314config TEST_LIST_SORT
1315 bool "Linked list sorting test"
1316 depends on DEBUG_KERNEL
1317 help
1318 Enable this to turn on 'list_sort()' function test. This test is
1319 executed only once during system boot, so affects only boot time.
1320
1321 If unsure, say N.
1322
1323config KPROBES_SANITY_TEST
1324 bool "Kprobes sanity tests"
1325 depends on DEBUG_KERNEL
1326 depends on KPROBES
1327 default n
1328 help
1329 This option provides for testing basic kprobes functionality on
1330 boot. A sample kprobe, jprobe and kretprobe are inserted and
1331 verified for functionality.
1332
1333 Say N if you are unsure.
1334
1335config BACKTRACE_SELF_TEST
1336 tristate "Self test for the backtrace code"
1337 depends on DEBUG_KERNEL
1338 default n
1339 help
1340 This option provides a kernel module that can be used to test
1341 the kernel stack backtrace code. This option is not useful
1342 for distributions or general kernels, but only for kernel
1343 developers working on architecture code.
1344
1345 Note that if you want to also test saved backtraces, you will
1346 have to enable STACKTRACE as well.
1347
1348 Say N if you are unsure.
1349
Michel Lespinasse910a7422012-10-08 16:30:39 -07001350config RBTREE_TEST
1351 tristate "Red-Black tree test"
1352 depends on m && DEBUG_KERNEL
1353 help
1354 A benchmark measuring the performance of the rbtree library.
1355 Also includes rbtree invariant checks.
1356
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001357config INTERVAL_TREE_TEST
1358 tristate "Interval tree test"
1359 depends on m && DEBUG_KERNEL
1360 help
1361 A benchmark measuring the performance of the interval tree library
1362
Dave Hansen881c5142013-07-01 13:04:44 -07001363config ATOMIC64_SELFTEST
1364 bool "Perform an atomic64_t self-test at boot"
1365 help
1366 Enable this option to test the atomic64_t functions at boot.
1367
1368 If unsure, say N.
1369
1370config ASYNC_RAID6_TEST
1371 tristate "Self test for hardware accelerated raid6 recovery"
1372 depends on ASYNC_RAID6_RECOV
1373 select ASYNC_MEMCPY
1374 ---help---
1375 This is a one-shot self test that permutes through the
1376 recovery of all the possible two disk failure scenarios for a
1377 N-disk array. Recovery is performed with the asynchronous
1378 raid6 recovery routines, and will optionally use an offload
1379 engine if one is available.
1380
1381 If unsure, say N.
1382
1383config TEST_STRING_HELPERS
1384 tristate "Test functions located in the string_helpers module at runtime"
1385
1386config TEST_KSTRTOX
1387 tristate "Test kstrto*() family of functions at runtime"
1388
1389endmenu # runtime tests
1390
Bernhard Kaindlf212ec42008-01-30 13:34:11 +01001391config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +01001392 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +01001393 depends on PCI && X86
1394 help
1395 If you want to debug problems which hang or crash the kernel early
1396 on boot and the crashing machine has a FireWire port, you can use
1397 this feature to remotely access the memory of the crashed machine
1398 over FireWire. This employs remote DMA as part of the OHCI1394
1399 specification which is now the standard for FireWire controllers.
1400
1401 With remote DMA, you can monitor the printk buffer remotely using
1402 firescope and access all memory below 4GB using fireproxy from gdb.
1403 Even controlling a kernel debugger is possible using remote DMA.
1404
1405 Usage:
1406
1407 If ohci1394_dma=early is used as boot parameter, it will initialize
1408 all OHCI1394 controllers which are found in the PCI config space.
1409
1410 As all changes to the FireWire bus such as enabling and disabling
1411 devices cause a bus reset and thereby disable remote DMA for all
1412 devices, be sure to have the cable plugged and FireWire enabled on
1413 the debugging host before booting the debug target for debugging.
1414
1415 This code (~1k) is freed after boot. By then, the firewire stack
1416 in charge of the OHCI-1394 controllers should be used instead.
1417
1418 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +01001419
Stefan Richter080de8c2008-02-28 20:54:43 +01001420config FIREWIRE_OHCI_REMOTE_DMA
1421 bool "Remote debugging over FireWire with firewire-ohci"
1422 depends on FIREWIRE_OHCI
1423 help
1424 This option lets you use the FireWire bus for remote debugging
1425 with help of the firewire-ohci driver. It enables unfiltered
1426 remote DMA in firewire-ohci.
1427 See Documentation/debugging-via-ohci1394.txt for more information.
1428
1429 If unsure, say N.
1430
Randy Dunlap152de302009-02-20 15:38:47 -08001431config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -07001432 bool "Build targets in Documentation/ tree"
1433 depends on HEADERS_CHECK
1434 help
1435 This option attempts to build objects from the source files in the
1436 kernel Documentation/ tree.
1437
1438 Say N if you are unsure.
1439
Jason Barone9d376f2009-02-05 11:51:38 -05001440config DYNAMIC_DEBUG
Jason Baron86151fd2009-02-05 11:53:15 -05001441 bool "Enable dynamic printk() support"
Jason Baron346e15b2008-08-12 16:46:19 -04001442 default n
1443 depends on PRINTK
Jason Baron86151fd2009-02-05 11:53:15 -05001444 depends on DEBUG_FS
Jason Baron346e15b2008-08-12 16:46:19 -04001445 help
1446
1447 Compiles debug level messages into the kernel, which would not
1448 otherwise be available at runtime. These messages can then be
Jason Baron86151fd2009-02-05 11:53:15 -05001449 enabled/disabled based on various levels of scope - per source file,
1450 function, module, format string, and line number. This mechanism
Jim Cromie29e36c92012-04-27 14:30:41 -06001451 implicitly compiles in all pr_debug() and dev_dbg() calls, which
1452 enlarges the kernel text size by about 2%.
1453
1454 If a source file is compiled with DEBUG flag set, any
1455 pr_debug() calls in it are enabled by default, but can be
1456 disabled at runtime as below. Note that DEBUG flag is
1457 turned on by many CONFIG_*DEBUG* options.
Jason Baron346e15b2008-08-12 16:46:19 -04001458
1459 Usage:
1460
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001461 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
Jason Baron86151fd2009-02-05 11:53:15 -05001462 which is contained in the 'debugfs' filesystem. Thus, the debugfs
1463 filesystem must first be mounted before making use of this feature.
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001464 We refer the control file as: <debugfs>/dynamic_debug/control. This
Jason Baron86151fd2009-02-05 11:53:15 -05001465 file contains a list of the debug statements that can be enabled. The
1466 format for each line of the file is:
Jason Baron346e15b2008-08-12 16:46:19 -04001467
Jason Baron86151fd2009-02-05 11:53:15 -05001468 filename:lineno [module]function flags format
Jason Baron346e15b2008-08-12 16:46:19 -04001469
Jason Baron86151fd2009-02-05 11:53:15 -05001470 filename : source file of the debug statement
1471 lineno : line number of the debug statement
1472 module : module that contains the debug statement
1473 function : function that contains the debug statement
Jim Cromie29e36c92012-04-27 14:30:41 -06001474 flags : '=p' means the line is turned 'on' for printing
Jason Baron86151fd2009-02-05 11:53:15 -05001475 format : the format used for the debug statement
Jason Baron346e15b2008-08-12 16:46:19 -04001476
1477 From a live system:
1478
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001479 nullarbor:~ # cat <debugfs>/dynamic_debug/control
Jason Baron86151fd2009-02-05 11:53:15 -05001480 # filename:lineno [module]function flags format
Jim Cromie29e36c92012-04-27 14:30:41 -06001481 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
1482 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
1483 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
Jason Baron346e15b2008-08-12 16:46:19 -04001484
Jason Baron86151fd2009-02-05 11:53:15 -05001485 Example usage:
Jason Baron346e15b2008-08-12 16:46:19 -04001486
Jason Baron86151fd2009-02-05 11:53:15 -05001487 // enable the message at line 1603 of file svcsock.c
1488 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001489 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001490
Jason Baron86151fd2009-02-05 11:53:15 -05001491 // enable all the messages in file svcsock.c
1492 nullarbor:~ # echo -n 'file svcsock.c +p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001493 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001494
Jason Baron86151fd2009-02-05 11:53:15 -05001495 // enable all the messages in the NFS server module
1496 nullarbor:~ # echo -n 'module nfsd +p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001497 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001498
Jason Baron86151fd2009-02-05 11:53:15 -05001499 // enable all 12 messages in the function svc_process()
1500 nullarbor:~ # echo -n 'func svc_process +p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001501 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001502
Jason Baron86151fd2009-02-05 11:53:15 -05001503 // disable all 12 messages in the function svc_process()
1504 nullarbor:~ # echo -n 'func svc_process -p' >
Florian Ragwitz2b2f68b2010-05-24 14:33:21 -07001505 <debugfs>/dynamic_debug/control
Jason Baron346e15b2008-08-12 16:46:19 -04001506
Jason Baron86151fd2009-02-05 11:53:15 -05001507 See Documentation/dynamic-debug-howto.txt for additional information.
Jason Baron346e15b2008-08-12 16:46:19 -04001508
Joerg Roedel5ee00bd2009-01-09 12:14:24 +01001509config DMA_API_DEBUG
1510 bool "Enable debugging of DMA-API usage"
1511 depends on HAVE_DMA_API_DEBUG
1512 help
1513 Enable this option to debug the use of the DMA API by device drivers.
1514 With this option you will be able to detect common bugs in device
1515 drivers like double-freeing of DMA mappings or freeing mappings that
1516 were never allocated.
1517 This option causes a performance degredation. Use only if you want
1518 to debug device drivers. If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -04001519
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001520source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02001521
1522source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001523