blob: 6b0c2d8a21294e9de3a1ca3738134746c035f2d5 [file] [log] [blame]
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
6 Selecting this option causes timing information to be
7 included in printk output. This allows you to measure
8 the interval between kernel operations, including bootup
9 operations. This is useful for identifying long delays
10 in kernel startup.
11
Jeff Garzikde488442007-10-25 04:06:13 -040012config ENABLE_WARN_DEPRECATED
13 bool "Enable __deprecated logic"
14 default y
15 help
16 Enable the __deprecated logic in the kernel build.
17 Disable this to suppress the "warning: 'foo' is deprecated
18 (declared at kernel/power/somefile.c:1234)" messages.
19
Andrew Mortoncebc04b2006-08-14 22:43:18 -070020config ENABLE_MUST_CHECK
21 bool "Enable __must_check logic"
22 default y
23 help
24 Enable the __must_check logic in the kernel build. Disable this to
25 suppress the "warning: ignoring return value of 'foo', declared with
26 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
Andi Kleen35bb5b12008-02-22 15:15:03 +010028config FRAME_WARN
29 int "Warn for stack frames larger than (needs gcc 4.4)"
30 range 0 8192
31 default 1024 if !64BIT
32 default 2048 if 64BIT
33 help
34 Tell gcc to warn at build time for stack frames larger than this.
35 Setting this too low will cause a lot of warnings.
36 Setting it to 0 disables the warning.
37 Requires gcc 4.4
38
Linus Torvalds1da177e2005-04-16 15:20:36 -070039config MAGIC_SYSRQ
40 bool "Magic SysRq key"
Adrian Bunkf346f4b2006-01-09 20:54:51 -080041 depends on !UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 help
43 If you say Y here, you will have some control over the system even
44 if the system crashes for example during kernel debugging (e.g., you
45 will be able to flush the buffer cache to disk, reboot the system
46 immediately or dump some status information). This is accomplished
47 by pressing various keys while holding SysRq (Alt+PrintScreen). It
48 also works on a serial console (on PC hardware at least), if you
49 send a BREAK and then within 5 seconds a command keypress. The
50 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
51 unless you really know what this hack does.
52
Arjan van de Venf71d20e2006-06-28 04:26:45 -070053config UNUSED_SYMBOLS
54 bool "Enable unused/obsolete exported symbols"
55 default y if X86
56 help
57 Unused but exported symbols make the kernel needlessly bigger. For
58 that reason most of these unused exports will soon be removed. This
59 option is provided temporarily to provide a transition period in case
60 some external kernel module needs one of these symbols anyway. If you
61 encounter such a case in your module, consider if you are actually
62 using the right API. (rationale: since nobody in the kernel is using
63 this in a module, there is a pretty good chance it's actually the
64 wrong interface to use). If you really need the symbol, please send a
65 mail to the linux kernel mailing list mentioning the symbol and why
66 you really need it, and what the merge plan to the mainline kernel for
67 your module is.
68
Don Mullisbf4735a2006-12-10 02:18:37 -080069config DEBUG_FS
70 bool "Debug Filesystem"
71 depends on SYSFS
72 help
73 debugfs is a virtual file system that kernel developers use to put
74 debugging files into. Enable this option to be able to read and
75 write to these files.
76
Robert P. J. Dayff543332008-05-20 00:06:00 +020077 For detailed documentation on the debugfs API, see
78 Documentation/DocBook/filesystems.
79
Don Mullisbf4735a2006-12-10 02:18:37 -080080 If unsure, say N.
81
82config HEADERS_CHECK
83 bool "Run 'make headers_check' when building vmlinux"
84 depends on !UML
85 help
86 This option will extract the user-visible kernel headers whenever
87 building the kernel, and will run basic sanity checks on them to
88 ensure that exported files do not attempt to include files which
89 were not exported, etc.
90
91 If you're making modifications to header files which are
92 relevant for userspace, say 'Y', and check the headers
93 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
94 your build tree), to make sure they're suitable.
95
Sam Ravnborg91341d42008-01-21 21:31:44 +010096config DEBUG_SECTION_MISMATCH
97 bool "Enable full Section mismatch analysis"
Sam Ravnborge5f95c82008-02-02 18:57:18 +010098 depends on UNDEFINED
Sam Ravnborgfa2144b2008-02-15 13:53:11 +010099 # This option is on purpose disabled for now.
100 # It will be enabled when we are down to a resonable number
101 # of section mismatch warnings (< 10 for an allyesconfig build)
Sam Ravnborg91341d42008-01-21 21:31:44 +0100102 help
103 The section mismatch analysis checks if there are illegal
104 references from one section to another section.
105 Linux will during link or during runtime drop some sections
106 and any use of code/data previously in these sections will
107 most likely result in an oops.
108 In the code functions and variables are annotated with
109 __init, __devinit etc. (see full list in include/linux/init.h)
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100110 which results in the code/data being placed in specific sections.
111 The section mismatch analysis is always done after a full
112 kernel build but enabling this option will in addition
Sam Ravnborg91341d42008-01-21 21:31:44 +0100113 do the following:
114 - Add the option -fno-inline-functions-called-once to gcc
115 When inlining a function annotated __init in a non-init
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100116 function we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100117 the analysis would not catch the illegal reference.
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100118 This option tells gcc to inline less but will also
Sam Ravnborg91341d42008-01-21 21:31:44 +0100119 result in a larger kernel.
120 - Run the section mismatch analysis for each module/built-in.o
121 When we run the section mismatch analysis on vmlinux.o we
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100122 lose valueble information about where the mismatch was
Sam Ravnborg91341d42008-01-21 21:31:44 +0100123 introduced.
124 Running the analysis for each module/built-in.o file
125 will tell where the mismatch happens much closer to the
126 source. The drawback is that we will report the same
127 mismatch at least twice.
Sam Ravnborg588ccd72008-01-24 21:12:37 +0100128 - Enable verbose reporting from modpost to help solving
129 the section mismatches reported.
Sam Ravnborg91341d42008-01-21 21:31:44 +0100130
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800131config DEBUG_KERNEL
132 bool "Kernel debugging"
133 help
134 Say Y here if you are developing drivers or trying to debug and
135 identify kernel problems.
136
David Woodhousea304e1b2007-02-12 00:52:00 -0800137config DEBUG_SHIRQ
138 bool "Debug shared IRQ handlers"
139 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
140 help
141 Enable this to generate a spurious interrupt as soon as a shared
142 interrupt handler is registered, and just before one is deregistered.
143 Drivers ought to be able to handle interrupts coming in at those
144 points; some don't and need to be caught.
145
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700146config DETECT_SOFTLOCKUP
147 bool "Detect Soft Lockups"
Heiko Carstensdea20a32006-10-11 01:20:44 -0700148 depends on DEBUG_KERNEL && !S390
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700149 default y
150 help
151 Say Y here to enable the kernel to detect "soft lockups",
152 which are bugs that cause the kernel to loop in kernel
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200153 mode for more than 60 seconds, without giving other tasks a
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700154 chance to run.
155
156 When a soft-lockup is detected, the kernel will print the
157 current stack trace (which you should report), but the
158 system will stay locked up. This feature has negligible
159 overhead.
160
161 (Note that "hard lockups" are separate type of bugs that
162 can be detected via the NMI-watchdog, on platforms that
163 support it.)
164
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200165config BOOTPARAM_SOFTLOCKUP_PANIC
166 bool "Panic (Reboot) On Soft Lockups"
167 depends on DETECT_SOFTLOCKUP
168 help
169 Say Y here to enable the kernel to panic on "soft lockups",
170 which are bugs that cause the kernel to loop in kernel
171 mode for more than 60 seconds, without giving other tasks a
172 chance to run.
173
174 The panic can be used in combination with panic_timeout,
175 to cause the system to reboot automatically after a
176 lockup has been detected. This feature is useful for
177 high-availability systems that have uptime guarantees and
178 where a lockup must be resolved ASAP.
179
180 Say N if unsure.
181
182config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
183 int
184 depends on DETECT_SOFTLOCKUP
185 range 0 1
186 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
187 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
188
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800189config DETECT_HUNG_TASK
190 bool "Detect Hung Tasks"
191 depends on DEBUG_KERNEL
Ingo Molnar77d05632009-04-07 08:55:36 +0200192 default DETECT_SOFTLOCKUP
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800193 help
194 Say Y here to enable the kernel to detect "hung tasks",
195 which are bugs that cause the task to be stuck in
196 uninterruptible "D" state indefinitiley.
197
198 When a hung task is detected, the kernel will print the
199 current stack trace (which you should report), but the
200 task will stay in uninterruptible state. If lockdep is
201 enabled then all held locks will also be reported. This
202 feature has negligible overhead.
203
204config BOOTPARAM_HUNG_TASK_PANIC
205 bool "Panic (Reboot) On Hung Tasks"
206 depends on DETECT_HUNG_TASK
207 help
208 Say Y here to enable the kernel to panic on "hung tasks",
209 which are bugs that cause the kernel to leave a task stuck
210 in uninterruptible "D" state.
211
212 The panic can be used in combination with panic_timeout,
213 to cause the system to reboot automatically after a
214 hung task has been detected. This feature is useful for
215 high-availability systems that have uptime guarantees and
216 where a hung tasks must be resolved ASAP.
217
218 Say N if unsure.
219
220config BOOTPARAM_HUNG_TASK_PANIC_VALUE
221 int
222 depends on DETECT_HUNG_TASK
223 range 0 1
224 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
225 default 1 if BOOTPARAM_HUNG_TASK_PANIC
226
Ingo Molnarb642b6d2007-07-09 18:52:00 +0200227config SCHED_DEBUG
228 bool "Collect scheduler debugging info"
229 depends on DEBUG_KERNEL && PROC_FS
230 default y
231 help
232 If you say Y here, the /proc/sched_debug file will be provided
233 that can help debug the scheduler. The runtime overhead of this
234 option is minimal.
235
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236config SCHEDSTATS
237 bool "Collect scheduler statistics"
238 depends on DEBUG_KERNEL && PROC_FS
239 help
240 If you say Y here, additional code will be inserted into the
241 scheduler and related routines to collect statistics about
242 scheduler behavior and provide them in /proc/schedstat. These
243 stats may be useful for both tuning and debugging the scheduler
244 If you aren't debugging the scheduler or trying to tune a specific
245 application, you can say N to avoid the very slight overhead
246 this adds.
247
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800248config TIMER_STATS
249 bool "Collect kernel timers statistics"
250 depends on DEBUG_KERNEL && PROC_FS
251 help
252 If you say Y here, additional code will be inserted into the
253 timer routines to collect statistics about kernel timers being
254 reprogrammed. The statistics can be read from /proc/timer_stats.
255 The statistics collection is started by writing 1 to /proc/timer_stats,
256 writing 0 stops it. This feature is useful to collect information
Ingo Molnarc1a834d2007-06-01 00:47:16 -0700257 about timer usage patterns in kernel and userspace. This feature
258 is lightweight if enabled in the kernel config but not activated
259 (it defaults to deactivated on bootup and will only be activated
260 if some application like powertop activates it explicitly).
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800261
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700262config DEBUG_OBJECTS
263 bool "Debug object operations"
264 depends on DEBUG_KERNEL
265 help
266 If you say Y here, additional code will be inserted into the
267 kernel to track the life time of various objects and validate
268 the operations on those objects.
269
270config DEBUG_OBJECTS_SELFTEST
271 bool "Debug objects selftest"
272 depends on DEBUG_OBJECTS
273 help
274 This enables the selftest of the object debug code.
275
276config DEBUG_OBJECTS_FREE
277 bool "Debug objects in freed memory"
278 depends on DEBUG_OBJECTS
279 help
280 This enables checks whether a k/v free operation frees an area
281 which contains an object which has not been deactivated
282 properly. This can make kmalloc/kfree-intensive workloads
283 much slower.
284
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700285config DEBUG_OBJECTS_TIMERS
286 bool "Debug timer objects"
287 depends on DEBUG_OBJECTS
288 help
289 If you say Y here, additional code will be inserted into the
290 timer routines to track the life time of timer objects and
291 validate the timer operations.
292
Ingo Molnar3ae70202008-11-26 10:02:00 +0100293config DEBUG_OBJECTS_ENABLE_DEFAULT
294 int "debug_objects bootup default value (0-1)"
295 range 0 1
296 default "1"
297 depends on DEBUG_OBJECTS
298 help
299 Debug objects boot parameter default value
300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800302 bool "Debug slab memory allocations"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200303 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 help
305 Say Y here to have the kernel do limited verification on memory
306 allocation as well as poisoning memory on free to catch use of freed
307 memory. This can make kmalloc/kfree-intensive workloads much slower.
308
Al Viro871751e2006-03-25 03:06:39 -0800309config DEBUG_SLAB_LEAK
310 bool "Memory leak debugging"
311 depends on DEBUG_SLAB
312
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700313config SLUB_DEBUG_ON
314 bool "SLUB debugging on by default"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200315 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700316 default n
317 help
318 Boot with debugging on by default. SLUB boots by default with
319 the runtime debug capabilities switched off. Enabling this is
320 equivalent to specifying the "slub_debug" parameter on boot.
321 There is no support for more fine grained debug control like
322 possible with slub_debug=xxx. SLUB debugging may be switched
323 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
324 "slub_debug=-".
325
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800326config SLUB_STATS
327 default n
328 bool "Enable SLUB performance statistics"
Christoph Lameter5b06c8532008-04-14 18:51:34 +0300329 depends on SLUB && SLUB_DEBUG && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800330 help
331 SLUB statistics are useful to debug SLUBs allocation behavior in
332 order find ways to optimize the allocator. This should never be
333 enabled for production use since keeping statistics slows down
334 the allocator by a few percentage points. The slabinfo command
335 supports the determination of the most active slabs to figure
336 out which slabs are relevant to a particular load.
337 Try running: slabinfo -DA
338
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100339config DEBUG_KMEMLEAK
340 bool "Kernel memory leak detector"
341 depends on DEBUG_KERNEL && EXPERIMENTAL && (X86 || ARM) && \
342 !MEMORY_HOTPLUG
343 select DEBUG_SLAB if SLAB
344 select SLUB_DEBUG if SLUB
345 select DEBUG_FS if SYSFS
346 select STACKTRACE if STACKTRACE_SUPPORT
347 select KALLSYMS
348 help
349 Say Y here if you want to enable the memory leak
350 detector. The memory allocation/freeing is traced in a way
351 similar to the Boehm's conservative garbage collector, the
352 difference being that the orphan objects are not freed but
353 only shown in /sys/kernel/debug/kmemleak. Enabling this
354 feature will introduce an overhead to memory
355 allocations. See Documentation/kmemleak.txt for more
356 details.
357
358 In order to access the kmemleak file, debugfs needs to be
359 mounted (usually at /sys/kernel/debug).
360
Catalin Marinas0822ee42009-06-11 13:24:14 +0100361config DEBUG_KMEMLEAK_TEST
362 tristate "Simple test for the kernel memory leak detector"
363 depends on DEBUG_KMEMLEAK
364 help
365 Say Y or M here to build a test for the kernel memory leak
366 detector. This option enables a module that explicitly leaks
367 memory.
368
369 If unsure, say N.
370
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371config DEBUG_PREEMPT
372 bool "Debug preemptible kernel"
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100373 depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 default y
375 help
376 If you say Y here then the kernel will use a debug variant of the
377 commonly used smp_processor_id() function and will print warnings
378 if kernel code uses it in a preemption-unsafe way. Also, the kernel
379 will detect preemption count underflows.
380
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700381config DEBUG_RT_MUTEXES
382 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700383 depends on DEBUG_KERNEL && RT_MUTEXES
384 help
385 This allows rt mutex semantics violations and rt mutex related
386 deadlocks (lockups) to be detected and reported automatically.
387
388config DEBUG_PI_LIST
389 bool
390 default y
391 depends on DEBUG_RT_MUTEXES
392
Thomas Gleixner61a87122006-06-27 02:54:56 -0700393config RT_MUTEX_TESTER
394 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700395 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700396 help
397 This option enables a rt-mutex tester.
398
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700400 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 depends on DEBUG_KERNEL
402 help
403 Say Y here and build SMP to catch missing spinlock initialization
404 and certain other kinds of spinlock errors commonly made. This is
405 best used in conjunction with the NMI watchdog so that spinlock
406 deadlocks are also debuggable.
407
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700408config DEBUG_MUTEXES
409 bool "Mutex debugging: basic checks"
410 depends on DEBUG_KERNEL
411 help
412 This feature allows mutex semantics violations to be detected and
413 reported.
414
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700415config DEBUG_LOCK_ALLOC
416 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700417 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700418 select DEBUG_SPINLOCK
419 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700420 select LOCKDEP
421 help
422 This feature will check whether any held lock (spinlock, rwlock,
423 mutex or rwsem) is incorrectly freed by the kernel, via any of the
424 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
425 vfree(), etc.), whether a live lock is incorrectly reinitialized via
426 spin_lock_init()/mutex_init()/etc., or whether there is any lock
427 held during task exit.
428
429config PROVE_LOCKING
430 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700431 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700432 select LOCKDEP
433 select DEBUG_SPINLOCK
434 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700435 select DEBUG_LOCK_ALLOC
436 default n
437 help
438 This feature enables the kernel to prove that all locking
439 that occurs in the kernel runtime is mathematically
440 correct: that under no circumstance could an arbitrary (and
441 not yet triggered) combination of observed locking
442 sequences (on an arbitrary number of CPUs, running an
443 arbitrary number of tasks and interrupt contexts) cause a
444 deadlock.
445
446 In short, this feature enables the kernel to report locking
447 related deadlocks before they actually occur.
448
449 The proof does not depend on how hard and complex a
450 deadlock scenario would be to trigger: how many
451 participant CPUs, tasks and irq-contexts would be needed
452 for it to trigger. The proof also does not depend on
453 timing: if a race and a resulting deadlock is possible
454 theoretically (no matter how unlikely the race scenario
455 is), it will be proven so and will immediately be
456 reported by the kernel (once the event is observed that
457 makes the deadlock theoretically possible).
458
459 If a deadlock is impossible (i.e. the locking rules, as
460 observed by the kernel, are mathematically correct), the
461 kernel reports nothing.
462
463 NOTE: this feature can also be enabled for rwlocks, mutexes
464 and rwsems - in which case all dependencies between these
465 different locking variants are observed and mapped too, and
466 the proof of observed correctness is also maintained for an
467 arbitrary combination of these separate locking variants.
468
469 For more details, see Documentation/lockdep-design.txt.
470
471config LOCKDEP
472 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700473 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700474 select STACKTRACE
Heiko Carstens75ee0342009-04-23 13:58:10 +0200475 select FRAME_POINTER if !X86 && !MIPS && !PPC && !ARM_UNWIND && !S390
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700476 select KALLSYMS
477 select KALLSYMS_ALL
478
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700479config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700480 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700481 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
482 select LOCKDEP
483 select DEBUG_SPINLOCK
484 select DEBUG_MUTEXES
485 select DEBUG_LOCK_ALLOC
486 default n
487 help
488 This feature enables tracking lock contention points
489
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700490 For more details, see Documentation/lockstat.txt
491
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700492config DEBUG_LOCKDEP
493 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700494 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700495 help
496 If you say Y here, the lock dependency engine will do
497 additional runtime checks to debug itself, at the price
498 of more runtime overhead.
499
500config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700501 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700502 bool
503 default y
504 depends on TRACE_IRQFLAGS_SUPPORT
505 depends on PROVE_LOCKING
506
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700508 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 depends on DEBUG_KERNEL
510 help
511 If you say Y here, various routines which may sleep will become very
512 noisy if they are called with a spinlock held.
513
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700514config DEBUG_LOCKING_API_SELFTESTS
515 bool "Locking API boot-time self-tests"
516 depends on DEBUG_KERNEL
517 help
518 Say Y here if you want the kernel to run a short self-test during
519 bootup. The self-test checks whether common types of locking bugs
520 are detected by debugging mechanisms or not. (if you disable
521 lock debugging then those bugs wont be detected of course.)
522 The following locking APIs are covered: spinlocks, rwlocks,
523 mutexes and rwsems.
524
Ingo Molnar8637c092006-07-03 00:24:38 -0700525config STACKTRACE
526 bool
527 depends on STACKTRACE_SUPPORT
528
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529config DEBUG_KOBJECT
530 bool "kobject debugging"
531 depends on DEBUG_KERNEL
532 help
533 If you say Y here, some extra kobject debugging messages will be sent
534 to the syslog.
535
536config DEBUG_HIGHMEM
537 bool "Highmem debugging"
538 depends on DEBUG_KERNEL && HIGHMEM
539 help
540 This options enables addition error checking for high memory systems.
541 Disable for production systems.
542
543config DEBUG_BUGVERBOSE
544 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700545 depends on BUG
David Howellsb920de12008-02-08 04:19:31 -0800546 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
547 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 default !EMBEDDED
549 help
550 Say Y here to make BUG() panics output the file name and line number
551 of the BUG call as well as the EIP and oops trace. This aids
552 debugging but costs about 70-100K of memory.
553
554config DEBUG_INFO
555 bool "Compile the kernel with debug info"
556 depends on DEBUG_KERNEL
557 help
558 If you say Y here the resulting kernel image will include
559 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600560 This adds debug symbols to the kernel and modules (gcc -g), and
561 is needed if you intend to use kernel crashdump or binary object
562 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 Say Y here only if you plan to debug the kernel.
564
565 If unsure, say N.
566
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800567config DEBUG_VM
568 bool "Debug VM"
569 depends on DEBUG_KERNEL
570 help
Nick Piggin13e74442006-01-06 00:10:58 -0800571 Enable this to turn on extended checks in the virtual-memory system
572 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800573
574 If unsure, say N.
575
Jiri Slaby59ea7462008-06-12 13:56:40 +0200576config DEBUG_VIRTUAL
577 bool "Debug VM translations"
578 depends on DEBUG_KERNEL && X86
579 help
580 Enable some costly sanity checks in virtual to page code. This can
581 catch mistakes with virt_to_page() and friends.
582
583 If unsure, say N.
584
David Howells8feae132009-01-08 12:04:47 +0000585config DEBUG_NOMMU_REGIONS
586 bool "Debug the global anon/private NOMMU mapping region tree"
587 depends on DEBUG_KERNEL && !MMU
588 help
589 This option causes the global tree of anonymous and private mapping
590 regions to be regularly checked for invalid topology.
591
Dave Hansenad775f52008-02-15 14:38:01 -0800592config DEBUG_WRITECOUNT
593 bool "Debug filesystem writers count"
594 depends on DEBUG_KERNEL
595 help
596 Enable this to catch wrong use of the writers count in struct
597 vfsmount. This will increase the size of each file struct by
598 32 bits.
599
600 If unsure, say N.
601
Mel Gorman6b74ab92008-07-23 21:26:49 -0700602config DEBUG_MEMORY_INIT
603 bool "Debug memory initialisation" if EMBEDDED
604 default !EMBEDDED
605 help
606 Enable this for additional checks during memory initialisation.
607 The sanity checks verify aspects of the VM such as the memory model
608 and other information provided by the architecture. Verbose
609 information will be printed at KERN_DEBUG loglevel depending
610 on the mminit_loglevel= command-line option.
611
612 If unsure, say Y
613
Dave Jones199a9af2006-09-29 01:59:00 -0700614config DEBUG_LIST
615 bool "Debug linked list manipulation"
616 depends on DEBUG_KERNEL
617 help
618 Enable this to turn on extended checks in the linked-list
619 walking routines.
620
621 If unsure, say N.
622
Jens Axboed6ec0842007-10-22 20:01:06 +0200623config DEBUG_SG
624 bool "Debug SG table operations"
625 depends on DEBUG_KERNEL
626 help
627 Enable this to turn on checks on scatter-gather tables. This can
628 help find problems with drivers that do not properly initialize
629 their sg tables.
630
631 If unsure, say N.
632
Arjan van de Ven1b2439d2008-08-15 15:29:38 -0700633config DEBUG_NOTIFIERS
634 bool "Debug notifier call chains"
635 depends on DEBUG_KERNEL
636 help
637 Enable this to turn on sanity checking for notifier call chains.
638 This is most useful for kernel developers to make sure that
639 modules properly unregister themselves from notifier chains.
640 This is a relatively cheap check but if you care about maximum
641 performance, say N.
642
Jeff Mahoney64dec402009-01-16 13:23:35 -0500643#
644# Select this config option from the architecture Kconfig, if it
645# it is preferred to always offer frame pointers as a config
646# option on the architecture (regardless of KERNEL_DEBUG):
647#
648config ARCH_WANT_FRAME_POINTERS
649 bool
650 help
651
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652config FRAME_POINTER
653 bool "Compile the kernel with frame pointers"
David Howellsb920de12008-02-08 04:19:31 -0800654 depends on DEBUG_KERNEL && \
Heiko Carstens75ee0342009-04-23 13:58:10 +0200655 (CRIS || M68K || M68KNOMMU || FRV || UML || \
Ingo Molnarda4276b2009-01-07 11:05:10 +0100656 AVR32 || SUPERH || BLACKFIN || MN10300) || \
657 ARCH_WANT_FRAME_POINTERS
658 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 help
Ingo Molnarda4276b2009-01-07 11:05:10 +0100660 If you say Y here the resulting kernel image will be slightly
661 larger and slower, but it gives very useful debugging information
662 in case of kernel bugs. (precise oopses/stacktraces/warnings)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700664config BOOT_PRINTK_DELAY
665 bool "Delay each boot printk message by N milliseconds"
666 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
667 help
668 This build option allows you to read kernel boot messages
669 by inserting a short delay after each one. The delay is
670 specified in milliseconds on the kernel command line,
671 using "boot_delay=N".
672
673 It is likely that you would also need to use "lpj=M" to preset
674 the "loops per jiffie" value.
675 See a previous boot log for the "lpj" value to use for your
676 system, and then set "lpj=M" before setting "boot_delay=N".
677 NOTE: Using this option may adversely affect SMP systems.
678 I.e., processors other than the first one may not boot up.
679 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
680 what it believes to be lockup conditions.
681
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800682config RCU_TORTURE_TEST
683 tristate "torture tests for RCU"
684 depends on DEBUG_KERNEL
685 default n
686 help
687 This option provides a kernel module that runs torture tests
688 on the RCU infrastructure. The kernel module may be built
689 after the fact on the running kernel to be tested, if desired.
690
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700691 Say Y here if you want RCU torture tests to be built into
692 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800693 Say M if you want the RCU torture tests to build as a module.
694 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700695
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700696config RCU_TORTURE_TEST_RUNNABLE
697 bool "torture tests for RCU runnable by default"
698 depends on RCU_TORTURE_TEST = y
699 default n
700 help
701 This option provides a way to build the RCU torture tests
702 directly into the kernel without them starting up at boot
703 time. You can use /proc/sys/kernel/rcutorture_runnable
704 to manually override this setting. This /proc file is
705 available only when the RCU torture tests have been built
706 into the kernel.
707
708 Say Y here if you want the RCU torture tests to start during
709 boot (you probably don't).
710 Say N here if you want the RCU torture tests to start only
711 after being manually enabled via /proc.
712
Paul E. McKenney2133b5d2008-10-02 16:06:39 -0700713config RCU_CPU_STALL_DETECTOR
Paul E. McKenney67182ae2008-08-10 18:35:38 -0700714 bool "Check for stalled CPUs delaying RCU grace periods"
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100715 depends on CLASSIC_RCU || TREE_RCU
716 default n
717 help
718 This option causes RCU to printk information on which
719 CPUs are delaying the current grace period, but only when
720 the grace period extends for excessive time periods.
721
722 Say Y if you want RCU to perform such checks.
723
724 Say N if you are unsure.
725
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +0100726config KPROBES_SANITY_TEST
727 bool "Kprobes sanity tests"
728 depends on DEBUG_KERNEL
729 depends on KPROBES
730 default n
731 help
732 This option provides for testing basic kprobes functionality on
733 boot. A sample kprobe, jprobe and kretprobe are inserted and
734 verified for functionality.
735
736 Say N if you are unsure.
737
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100738config BACKTRACE_SELF_TEST
739 tristate "Self test for the backtrace code"
740 depends on DEBUG_KERNEL
741 default n
742 help
743 This option provides a kernel module that can be used to test
744 the kernel stack backtrace code. This option is not useful
745 for distributions or general kernels, but only for kernel
746 developers working on architecture code.
747
Vegard Nossumad118c52008-06-27 18:04:48 +0200748 Note that if you want to also test saved backtraces, you will
749 have to enable STACKTRACE as well.
750
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100751 Say N if you are unsure.
752
Tejun Heo870d6652008-08-25 19:47:25 +0900753config DEBUG_BLOCK_EXT_DEVT
754 bool "Force extended block device numbers and spread them"
755 depends on DEBUG_KERNEL
756 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +0200757 default n
Tejun Heo870d6652008-08-25 19:47:25 +0900758 help
Tejun Heo0e11e342008-10-13 10:46:01 +0200759 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
760 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
761 YOU ARE DOING. Distros, please enable this and fix whatever
762 is broken.
763
Tejun Heo870d6652008-08-25 19:47:25 +0900764 Conventionally, block device numbers are allocated from
765 predetermined contiguous area. However, extended block area
766 may introduce non-contiguous block device numbers. This
767 option forces most block device numbers to be allocated from
768 the extended space and spreads them to discover kernel or
769 userland code paths which assume predetermined contiguous
770 device number allocation.
771
Tejun Heo55dc7db2008-09-01 13:44:35 +0200772 Note that turning on this debug option shuffles all the
773 device numbers for all IDE and SCSI devices including libata
774 ones, so root partition specified using device number
775 directly (via rdev or root=MAJ:MIN) won't work anymore.
776 Textual device names (root=/dev/sdXn) will continue to work.
777
Tejun Heo870d6652008-08-25 19:47:25 +0900778 Say N if you are unsure.
779
Ankita Garg8bb31b92006-10-02 02:17:36 -0700780config LKDTM
781 tristate "Linux Kernel Dump Test Tool Module"
Don Mullisbf4735a2006-12-10 02:18:37 -0800782 depends on DEBUG_KERNEL
Ankita Garg8bb31b92006-10-02 02:17:36 -0700783 depends on KPROBES
Chris Snookfddd9cf2008-02-23 15:23:26 -0800784 depends on BLOCK
Ankita Garg8bb31b92006-10-02 02:17:36 -0700785 default n
786 help
787 This module enables testing of the different dumping mechanisms by
788 inducing system failures at predefined crash points.
789 If you don't need it: say N
790 Choose M here to compile this code as a module. The module will be
791 called lkdtm.
792
793 Documentation on how to use the module can be found in
794 drivers/misc/lkdtm.c
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800795
796config FAULT_INJECTION
Andrew Morton1ab85092006-12-08 02:39:49 -0800797 bool "Fault-injection framework"
798 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -0800799 help
800 Provide fault-injection framework.
801 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800802
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800803config FAILSLAB
Andrew Morton1ab85092006-12-08 02:39:49 -0800804 bool "Fault-injection capability for kmalloc"
805 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +0900806 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800807 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800808 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800809
Akinobu Mita933e3122006-12-08 02:39:45 -0800810config FAIL_PAGE_ALLOC
811 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab85092006-12-08 02:39:49 -0800812 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800813 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800814 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800815
Akinobu Mitac17bb492006-12-08 02:39:46 -0800816config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100817 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -0700818 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -0800819 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800820 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800821
Jens Axboe581d4e22008-09-14 05:56:33 -0700822config FAIL_IO_TIMEOUT
823 bool "Faul-injection capability for faking disk interrupts"
824 depends on FAULT_INJECTION && BLOCK
825 help
826 Provide fault-injection capability on end IO handling. This
827 will make the block layer "forget" an interrupt as configured,
828 thus exercising the error handling.
829
830 Only works with drivers that use the generic timeout handling,
831 for others it wont do anything.
832
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800833config FAULT_INJECTION_DEBUG_FS
834 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab85092006-12-08 02:39:49 -0800835 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800836 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800837 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -0800838
839config FAULT_INJECTION_STACKTRACE_FILTER
840 bool "stacktrace filter for fault-injection capabilities"
841 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -0700842 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -0800843 select STACKTRACE
Heiko Carstens75ee0342009-04-23 13:58:10 +0200844 select FRAME_POINTER if !PPC && !S390
Akinobu Mita1df49002007-02-20 13:57:56 -0800845 help
846 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700847
Arjan van de Ven97455122008-01-25 21:08:34 +0100848config LATENCYTOP
849 bool "Latency measuring infrastructure"
Heiko Carstens75ee0342009-04-23 13:58:10 +0200850 select FRAME_POINTER if !MIPS && !PPC && !S390
Arjan van de Ven97455122008-01-25 21:08:34 +0100851 select KALLSYMS
852 select KALLSYMS_ALL
853 select STACKTRACE
854 select SCHEDSTATS
855 select SCHED_DEBUG
Heiko Carstensaa7d9352008-02-01 17:45:14 +0100856 depends on HAVE_LATENCYTOP_SUPPORT
Arjan van de Ven97455122008-01-25 21:08:34 +0100857 help
858 Enable this option if you want to use the LatencyTOP tool
859 to find out which userspace is blocking on what kernel operations.
860
Andi Kleen9e94cd32008-08-16 07:53:05 +0200861config SYSCTL_SYSCALL_CHECK
862 bool "Sysctl checks"
863 depends on SYSCTL_SYSCALL
864 ---help---
865 sys_sysctl uses binary paths that have been found challenging
866 to properly maintain and use. This enables checks that help
867 you to keep things correct.
868
Akinobu Mita6a11f752009-03-31 15:23:17 -0700869source mm/Kconfig.debug
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +0200870source kernel/trace/Kconfig
871
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100872config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +0100873 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100874 depends on PCI && X86
875 help
876 If you want to debug problems which hang or crash the kernel early
877 on boot and the crashing machine has a FireWire port, you can use
878 this feature to remotely access the memory of the crashed machine
879 over FireWire. This employs remote DMA as part of the OHCI1394
880 specification which is now the standard for FireWire controllers.
881
882 With remote DMA, you can monitor the printk buffer remotely using
883 firescope and access all memory below 4GB using fireproxy from gdb.
884 Even controlling a kernel debugger is possible using remote DMA.
885
886 Usage:
887
888 If ohci1394_dma=early is used as boot parameter, it will initialize
889 all OHCI1394 controllers which are found in the PCI config space.
890
891 As all changes to the FireWire bus such as enabling and disabling
892 devices cause a bus reset and thereby disable remote DMA for all
893 devices, be sure to have the cable plugged and FireWire enabled on
894 the debugging host before booting the debug target for debugging.
895
896 This code (~1k) is freed after boot. By then, the firewire stack
897 in charge of the OHCI-1394 controllers should be used instead.
898
899 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +0100900
Stefan Richter080de8c2008-02-28 20:54:43 +0100901config FIREWIRE_OHCI_REMOTE_DMA
902 bool "Remote debugging over FireWire with firewire-ohci"
903 depends on FIREWIRE_OHCI
904 help
905 This option lets you use the FireWire bus for remote debugging
906 with help of the firewire-ohci driver. It enables unfiltered
907 remote DMA in firewire-ohci.
908 See Documentation/debugging-via-ohci1394.txt for more information.
909
910 If unsure, say N.
911
Randy Dunlap152de302009-02-20 15:38:47 -0800912config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -0700913 bool "Build targets in Documentation/ tree"
914 depends on HEADERS_CHECK
915 help
916 This option attempts to build objects from the source files in the
917 kernel Documentation/ tree.
918
919 Say N if you are unsure.
920
Jason Barone9d376f2009-02-05 11:51:38 -0500921config DYNAMIC_DEBUG
Jason Baron86151fd2009-02-05 11:53:15 -0500922 bool "Enable dynamic printk() support"
Jason Baron346e15b2008-08-12 16:46:19 -0400923 default n
924 depends on PRINTK
Jason Baron86151fd2009-02-05 11:53:15 -0500925 depends on DEBUG_FS
Jason Baron346e15b2008-08-12 16:46:19 -0400926 help
927
928 Compiles debug level messages into the kernel, which would not
929 otherwise be available at runtime. These messages can then be
Jason Baron86151fd2009-02-05 11:53:15 -0500930 enabled/disabled based on various levels of scope - per source file,
931 function, module, format string, and line number. This mechanism
932 implicitly enables all pr_debug() and dev_dbg() calls. The impact of
933 this compile option is a larger kernel text size of about 2%.
Jason Baron346e15b2008-08-12 16:46:19 -0400934
935 Usage:
936
Jason Baron86151fd2009-02-05 11:53:15 -0500937 Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file,
938 which is contained in the 'debugfs' filesystem. Thus, the debugfs
939 filesystem must first be mounted before making use of this feature.
940 We refer the control file as: <debugfs>/dynamic_debug/ddebug. This
941 file contains a list of the debug statements that can be enabled. The
942 format for each line of the file is:
Jason Baron346e15b2008-08-12 16:46:19 -0400943
Jason Baron86151fd2009-02-05 11:53:15 -0500944 filename:lineno [module]function flags format
Jason Baron346e15b2008-08-12 16:46:19 -0400945
Jason Baron86151fd2009-02-05 11:53:15 -0500946 filename : source file of the debug statement
947 lineno : line number of the debug statement
948 module : module that contains the debug statement
949 function : function that contains the debug statement
950 flags : 'p' means the line is turned 'on' for printing
951 format : the format used for the debug statement
Jason Baron346e15b2008-08-12 16:46:19 -0400952
953 From a live system:
954
Jason Baron86151fd2009-02-05 11:53:15 -0500955 nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
956 # filename:lineno [module]function flags format
957 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
958 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
959 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
Jason Baron346e15b2008-08-12 16:46:19 -0400960
Jason Baron86151fd2009-02-05 11:53:15 -0500961 Example usage:
Jason Baron346e15b2008-08-12 16:46:19 -0400962
Jason Baron86151fd2009-02-05 11:53:15 -0500963 // enable the message at line 1603 of file svcsock.c
964 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
965 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400966
Jason Baron86151fd2009-02-05 11:53:15 -0500967 // enable all the messages in file svcsock.c
968 nullarbor:~ # echo -n 'file svcsock.c +p' >
969 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400970
Jason Baron86151fd2009-02-05 11:53:15 -0500971 // enable all the messages in the NFS server module
972 nullarbor:~ # echo -n 'module nfsd +p' >
973 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400974
Jason Baron86151fd2009-02-05 11:53:15 -0500975 // enable all 12 messages in the function svc_process()
976 nullarbor:~ # echo -n 'func svc_process +p' >
977 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400978
Jason Baron86151fd2009-02-05 11:53:15 -0500979 // disable all 12 messages in the function svc_process()
980 nullarbor:~ # echo -n 'func svc_process -p' >
981 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400982
Jason Baron86151fd2009-02-05 11:53:15 -0500983 See Documentation/dynamic-debug-howto.txt for additional information.
Jason Baron346e15b2008-08-12 16:46:19 -0400984
Joerg Roedel5ee00bd2009-01-09 12:14:24 +0100985config DMA_API_DEBUG
986 bool "Enable debugging of DMA-API usage"
987 depends on HAVE_DMA_API_DEBUG
988 help
989 Enable this option to debug the use of the DMA API by device drivers.
990 With this option you will be able to detect common bugs in device
991 drivers like double-freeing of DMA mappings or freeing mappings that
992 were never allocated.
993 This option causes a performance degredation. Use only if you want
994 to debug device drivers. If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -0400995
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700996source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +0200997
998source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +0200999
1000source "lib/Kconfig.kmemcheck"