blob: 4c32b1a1a06e393ad5d8844cdbefa00994965c2a [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
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100343 select DEBUG_FS if SYSFS
344 select STACKTRACE if STACKTRACE_SUPPORT
345 select KALLSYMS
346 help
347 Say Y here if you want to enable the memory leak
348 detector. The memory allocation/freeing is traced in a way
349 similar to the Boehm's conservative garbage collector, the
350 difference being that the orphan objects are not freed but
351 only shown in /sys/kernel/debug/kmemleak. Enabling this
352 feature will introduce an overhead to memory
353 allocations. See Documentation/kmemleak.txt for more
354 details.
355
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100356 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
357 of finding leaks due to the slab objects poisoning.
358
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100359 In order to access the kmemleak file, debugfs needs to be
360 mounted (usually at /sys/kernel/debug).
361
Catalin Marinas0822ee42009-06-11 13:24:14 +0100362config DEBUG_KMEMLEAK_TEST
363 tristate "Simple test for the kernel memory leak detector"
364 depends on DEBUG_KMEMLEAK
365 help
366 Say Y or M here to build a test for the kernel memory leak
367 detector. This option enables a module that explicitly leaks
368 memory.
369
370 If unsure, say N.
371
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372config DEBUG_PREEMPT
373 bool "Debug preemptible kernel"
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100374 depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 default y
376 help
377 If you say Y here then the kernel will use a debug variant of the
378 commonly used smp_processor_id() function and will print warnings
379 if kernel code uses it in a preemption-unsafe way. Also, the kernel
380 will detect preemption count underflows.
381
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700382config DEBUG_RT_MUTEXES
383 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700384 depends on DEBUG_KERNEL && RT_MUTEXES
385 help
386 This allows rt mutex semantics violations and rt mutex related
387 deadlocks (lockups) to be detected and reported automatically.
388
389config DEBUG_PI_LIST
390 bool
391 default y
392 depends on DEBUG_RT_MUTEXES
393
Thomas Gleixner61a87122006-06-27 02:54:56 -0700394config RT_MUTEX_TESTER
395 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700396 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700397 help
398 This option enables a rt-mutex tester.
399
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700401 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 depends on DEBUG_KERNEL
403 help
404 Say Y here and build SMP to catch missing spinlock initialization
405 and certain other kinds of spinlock errors commonly made. This is
406 best used in conjunction with the NMI watchdog so that spinlock
407 deadlocks are also debuggable.
408
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700409config DEBUG_MUTEXES
410 bool "Mutex debugging: basic checks"
411 depends on DEBUG_KERNEL
412 help
413 This feature allows mutex semantics violations to be detected and
414 reported.
415
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700416config DEBUG_LOCK_ALLOC
417 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700418 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700419 select DEBUG_SPINLOCK
420 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700421 select LOCKDEP
422 help
423 This feature will check whether any held lock (spinlock, rwlock,
424 mutex or rwsem) is incorrectly freed by the kernel, via any of the
425 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
426 vfree(), etc.), whether a live lock is incorrectly reinitialized via
427 spin_lock_init()/mutex_init()/etc., or whether there is any lock
428 held during task exit.
429
430config PROVE_LOCKING
431 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700432 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700433 select LOCKDEP
434 select DEBUG_SPINLOCK
435 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700436 select DEBUG_LOCK_ALLOC
437 default n
438 help
439 This feature enables the kernel to prove that all locking
440 that occurs in the kernel runtime is mathematically
441 correct: that under no circumstance could an arbitrary (and
442 not yet triggered) combination of observed locking
443 sequences (on an arbitrary number of CPUs, running an
444 arbitrary number of tasks and interrupt contexts) cause a
445 deadlock.
446
447 In short, this feature enables the kernel to report locking
448 related deadlocks before they actually occur.
449
450 The proof does not depend on how hard and complex a
451 deadlock scenario would be to trigger: how many
452 participant CPUs, tasks and irq-contexts would be needed
453 for it to trigger. The proof also does not depend on
454 timing: if a race and a resulting deadlock is possible
455 theoretically (no matter how unlikely the race scenario
456 is), it will be proven so and will immediately be
457 reported by the kernel (once the event is observed that
458 makes the deadlock theoretically possible).
459
460 If a deadlock is impossible (i.e. the locking rules, as
461 observed by the kernel, are mathematically correct), the
462 kernel reports nothing.
463
464 NOTE: this feature can also be enabled for rwlocks, mutexes
465 and rwsems - in which case all dependencies between these
466 different locking variants are observed and mapped too, and
467 the proof of observed correctness is also maintained for an
468 arbitrary combination of these separate locking variants.
469
470 For more details, see Documentation/lockdep-design.txt.
471
472config LOCKDEP
473 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700474 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700475 select STACKTRACE
Peter Zijlstra00540e52009-06-12 10:04:01 +0200476 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700477 select KALLSYMS
478 select KALLSYMS_ALL
479
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700480config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700481 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700482 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
483 select LOCKDEP
484 select DEBUG_SPINLOCK
485 select DEBUG_MUTEXES
486 select DEBUG_LOCK_ALLOC
487 default n
488 help
489 This feature enables tracking lock contention points
490
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700491 For more details, see Documentation/lockstat.txt
492
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700493config DEBUG_LOCKDEP
494 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700495 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700496 help
497 If you say Y here, the lock dependency engine will do
498 additional runtime checks to debug itself, at the price
499 of more runtime overhead.
500
501config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700502 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700503 bool
504 default y
505 depends on TRACE_IRQFLAGS_SUPPORT
506 depends on PROVE_LOCKING
507
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700509 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 depends on DEBUG_KERNEL
511 help
512 If you say Y here, various routines which may sleep will become very
513 noisy if they are called with a spinlock held.
514
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700515config DEBUG_LOCKING_API_SELFTESTS
516 bool "Locking API boot-time self-tests"
517 depends on DEBUG_KERNEL
518 help
519 Say Y here if you want the kernel to run a short self-test during
520 bootup. The self-test checks whether common types of locking bugs
521 are detected by debugging mechanisms or not. (if you disable
522 lock debugging then those bugs wont be detected of course.)
523 The following locking APIs are covered: spinlocks, rwlocks,
524 mutexes and rwsems.
525
Ingo Molnar8637c092006-07-03 00:24:38 -0700526config STACKTRACE
527 bool
528 depends on STACKTRACE_SUPPORT
529
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530config DEBUG_KOBJECT
531 bool "kobject debugging"
532 depends on DEBUG_KERNEL
533 help
534 If you say Y here, some extra kobject debugging messages will be sent
535 to the syslog.
536
537config DEBUG_HIGHMEM
538 bool "Highmem debugging"
539 depends on DEBUG_KERNEL && HIGHMEM
540 help
541 This options enables addition error checking for high memory systems.
542 Disable for production systems.
543
544config DEBUG_BUGVERBOSE
545 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700546 depends on BUG
David Howellsb920de12008-02-08 04:19:31 -0800547 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
548 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 default !EMBEDDED
550 help
551 Say Y here to make BUG() panics output the file name and line number
552 of the BUG call as well as the EIP and oops trace. This aids
553 debugging but costs about 70-100K of memory.
554
555config DEBUG_INFO
556 bool "Compile the kernel with debug info"
557 depends on DEBUG_KERNEL
558 help
559 If you say Y here the resulting kernel image will include
560 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600561 This adds debug symbols to the kernel and modules (gcc -g), and
562 is needed if you intend to use kernel crashdump or binary object
563 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 Say Y here only if you plan to debug the kernel.
565
566 If unsure, say N.
567
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800568config DEBUG_VM
569 bool "Debug VM"
570 depends on DEBUG_KERNEL
571 help
Nick Piggin13e74442006-01-06 00:10:58 -0800572 Enable this to turn on extended checks in the virtual-memory system
573 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800574
575 If unsure, say N.
576
Jiri Slaby59ea7462008-06-12 13:56:40 +0200577config DEBUG_VIRTUAL
578 bool "Debug VM translations"
579 depends on DEBUG_KERNEL && X86
580 help
581 Enable some costly sanity checks in virtual to page code. This can
582 catch mistakes with virt_to_page() and friends.
583
584 If unsure, say N.
585
David Howells8feae132009-01-08 12:04:47 +0000586config DEBUG_NOMMU_REGIONS
587 bool "Debug the global anon/private NOMMU mapping region tree"
588 depends on DEBUG_KERNEL && !MMU
589 help
590 This option causes the global tree of anonymous and private mapping
591 regions to be regularly checked for invalid topology.
592
Dave Hansenad775f52008-02-15 14:38:01 -0800593config DEBUG_WRITECOUNT
594 bool "Debug filesystem writers count"
595 depends on DEBUG_KERNEL
596 help
597 Enable this to catch wrong use of the writers count in struct
598 vfsmount. This will increase the size of each file struct by
599 32 bits.
600
601 If unsure, say N.
602
Mel Gorman6b74ab92008-07-23 21:26:49 -0700603config DEBUG_MEMORY_INIT
604 bool "Debug memory initialisation" if EMBEDDED
605 default !EMBEDDED
606 help
607 Enable this for additional checks during memory initialisation.
608 The sanity checks verify aspects of the VM such as the memory model
609 and other information provided by the architecture. Verbose
610 information will be printed at KERN_DEBUG loglevel depending
611 on the mminit_loglevel= command-line option.
612
613 If unsure, say Y
614
Dave Jones199a9af2006-09-29 01:59:00 -0700615config DEBUG_LIST
616 bool "Debug linked list manipulation"
617 depends on DEBUG_KERNEL
618 help
619 Enable this to turn on extended checks in the linked-list
620 walking routines.
621
622 If unsure, say N.
623
Jens Axboed6ec0842007-10-22 20:01:06 +0200624config DEBUG_SG
625 bool "Debug SG table operations"
626 depends on DEBUG_KERNEL
627 help
628 Enable this to turn on checks on scatter-gather tables. This can
629 help find problems with drivers that do not properly initialize
630 their sg tables.
631
632 If unsure, say N.
633
Arjan van de Ven1b2439d2008-08-15 15:29:38 -0700634config DEBUG_NOTIFIERS
635 bool "Debug notifier call chains"
636 depends on DEBUG_KERNEL
637 help
638 Enable this to turn on sanity checking for notifier call chains.
639 This is most useful for kernel developers to make sure that
640 modules properly unregister themselves from notifier chains.
641 This is a relatively cheap check but if you care about maximum
642 performance, say N.
643
Jeff Mahoney64dec402009-01-16 13:23:35 -0500644#
645# Select this config option from the architecture Kconfig, if it
646# it is preferred to always offer frame pointers as a config
647# option on the architecture (regardless of KERNEL_DEBUG):
648#
649config ARCH_WANT_FRAME_POINTERS
650 bool
651 help
652
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653config FRAME_POINTER
654 bool "Compile the kernel with frame pointers"
David Howellsb920de12008-02-08 04:19:31 -0800655 depends on DEBUG_KERNEL && \
Heiko Carstens75ee0342009-04-23 13:58:10 +0200656 (CRIS || M68K || M68KNOMMU || FRV || UML || \
Ingo Molnarda4276b2009-01-07 11:05:10 +0100657 AVR32 || SUPERH || BLACKFIN || MN10300) || \
658 ARCH_WANT_FRAME_POINTERS
659 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 help
Ingo Molnarda4276b2009-01-07 11:05:10 +0100661 If you say Y here the resulting kernel image will be slightly
662 larger and slower, but it gives very useful debugging information
663 in case of kernel bugs. (precise oopses/stacktraces/warnings)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700665config BOOT_PRINTK_DELAY
666 bool "Delay each boot printk message by N milliseconds"
667 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
668 help
669 This build option allows you to read kernel boot messages
670 by inserting a short delay after each one. The delay is
671 specified in milliseconds on the kernel command line,
672 using "boot_delay=N".
673
674 It is likely that you would also need to use "lpj=M" to preset
675 the "loops per jiffie" value.
676 See a previous boot log for the "lpj" value to use for your
677 system, and then set "lpj=M" before setting "boot_delay=N".
678 NOTE: Using this option may adversely affect SMP systems.
679 I.e., processors other than the first one may not boot up.
680 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
681 what it believes to be lockup conditions.
682
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800683config RCU_TORTURE_TEST
684 tristate "torture tests for RCU"
685 depends on DEBUG_KERNEL
686 default n
687 help
688 This option provides a kernel module that runs torture tests
689 on the RCU infrastructure. The kernel module may be built
690 after the fact on the running kernel to be tested, if desired.
691
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700692 Say Y here if you want RCU torture tests to be built into
693 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800694 Say M if you want the RCU torture tests to build as a module.
695 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700696
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700697config RCU_TORTURE_TEST_RUNNABLE
698 bool "torture tests for RCU runnable by default"
699 depends on RCU_TORTURE_TEST = y
700 default n
701 help
702 This option provides a way to build the RCU torture tests
703 directly into the kernel without them starting up at boot
704 time. You can use /proc/sys/kernel/rcutorture_runnable
705 to manually override this setting. This /proc file is
706 available only when the RCU torture tests have been built
707 into the kernel.
708
709 Say Y here if you want the RCU torture tests to start during
710 boot (you probably don't).
711 Say N here if you want the RCU torture tests to start only
712 after being manually enabled via /proc.
713
Paul E. McKenney2133b5d2008-10-02 16:06:39 -0700714config RCU_CPU_STALL_DETECTOR
Paul E. McKenney67182ae2008-08-10 18:35:38 -0700715 bool "Check for stalled CPUs delaying RCU grace periods"
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100716 depends on CLASSIC_RCU || TREE_RCU
717 default n
718 help
719 This option causes RCU to printk information on which
720 CPUs are delaying the current grace period, but only when
721 the grace period extends for excessive time periods.
722
723 Say Y if you want RCU to perform such checks.
724
725 Say N if you are unsure.
726
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +0100727config KPROBES_SANITY_TEST
728 bool "Kprobes sanity tests"
729 depends on DEBUG_KERNEL
730 depends on KPROBES
731 default n
732 help
733 This option provides for testing basic kprobes functionality on
734 boot. A sample kprobe, jprobe and kretprobe are inserted and
735 verified for functionality.
736
737 Say N if you are unsure.
738
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100739config BACKTRACE_SELF_TEST
740 tristate "Self test for the backtrace code"
741 depends on DEBUG_KERNEL
742 default n
743 help
744 This option provides a kernel module that can be used to test
745 the kernel stack backtrace code. This option is not useful
746 for distributions or general kernels, but only for kernel
747 developers working on architecture code.
748
Vegard Nossumad118c52008-06-27 18:04:48 +0200749 Note that if you want to also test saved backtraces, you will
750 have to enable STACKTRACE as well.
751
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100752 Say N if you are unsure.
753
Tejun Heo870d6652008-08-25 19:47:25 +0900754config DEBUG_BLOCK_EXT_DEVT
755 bool "Force extended block device numbers and spread them"
756 depends on DEBUG_KERNEL
757 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +0200758 default n
Tejun Heo870d6652008-08-25 19:47:25 +0900759 help
Tejun Heo0e11e342008-10-13 10:46:01 +0200760 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
761 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
762 YOU ARE DOING. Distros, please enable this and fix whatever
763 is broken.
764
Tejun Heo870d6652008-08-25 19:47:25 +0900765 Conventionally, block device numbers are allocated from
766 predetermined contiguous area. However, extended block area
767 may introduce non-contiguous block device numbers. This
768 option forces most block device numbers to be allocated from
769 the extended space and spreads them to discover kernel or
770 userland code paths which assume predetermined contiguous
771 device number allocation.
772
Tejun Heo55dc7db2008-09-01 13:44:35 +0200773 Note that turning on this debug option shuffles all the
774 device numbers for all IDE and SCSI devices including libata
775 ones, so root partition specified using device number
776 directly (via rdev or root=MAJ:MIN) won't work anymore.
777 Textual device names (root=/dev/sdXn) will continue to work.
778
Tejun Heo870d6652008-08-25 19:47:25 +0900779 Say N if you are unsure.
780
Ankita Garg8bb31b92006-10-02 02:17:36 -0700781config LKDTM
782 tristate "Linux Kernel Dump Test Tool Module"
Don Mullisbf4735a2006-12-10 02:18:37 -0800783 depends on DEBUG_KERNEL
Ankita Garg8bb31b92006-10-02 02:17:36 -0700784 depends on KPROBES
Chris Snookfddd9cf2008-02-23 15:23:26 -0800785 depends on BLOCK
Ankita Garg8bb31b92006-10-02 02:17:36 -0700786 default n
787 help
788 This module enables testing of the different dumping mechanisms by
789 inducing system failures at predefined crash points.
790 If you don't need it: say N
791 Choose M here to compile this code as a module. The module will be
792 called lkdtm.
793
794 Documentation on how to use the module can be found in
795 drivers/misc/lkdtm.c
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800796
797config FAULT_INJECTION
Andrew Morton1ab85092006-12-08 02:39:49 -0800798 bool "Fault-injection framework"
799 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -0800800 help
801 Provide fault-injection framework.
802 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800803
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800804config FAILSLAB
Andrew Morton1ab85092006-12-08 02:39:49 -0800805 bool "Fault-injection capability for kmalloc"
806 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +0900807 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800808 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800809 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800810
Akinobu Mita933e3122006-12-08 02:39:45 -0800811config FAIL_PAGE_ALLOC
812 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab85092006-12-08 02:39:49 -0800813 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800814 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800815 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800816
Akinobu Mitac17bb492006-12-08 02:39:46 -0800817config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100818 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -0700819 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -0800820 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800821 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800822
Jens Axboe581d4e22008-09-14 05:56:33 -0700823config FAIL_IO_TIMEOUT
824 bool "Faul-injection capability for faking disk interrupts"
825 depends on FAULT_INJECTION && BLOCK
826 help
827 Provide fault-injection capability on end IO handling. This
828 will make the block layer "forget" an interrupt as configured,
829 thus exercising the error handling.
830
831 Only works with drivers that use the generic timeout handling,
832 for others it wont do anything.
833
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800834config FAULT_INJECTION_DEBUG_FS
835 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab85092006-12-08 02:39:49 -0800836 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800837 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800838 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -0800839
840config FAULT_INJECTION_STACKTRACE_FILTER
841 bool "stacktrace filter for fault-injection capabilities"
842 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -0700843 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -0800844 select STACKTRACE
Heiko Carstens75ee0342009-04-23 13:58:10 +0200845 select FRAME_POINTER if !PPC && !S390
Akinobu Mita1df49002007-02-20 13:57:56 -0800846 help
847 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700848
Arjan van de Ven97455122008-01-25 21:08:34 +0100849config LATENCYTOP
850 bool "Latency measuring infrastructure"
Heiko Carstens75ee0342009-04-23 13:58:10 +0200851 select FRAME_POINTER if !MIPS && !PPC && !S390
Arjan van de Ven97455122008-01-25 21:08:34 +0100852 select KALLSYMS
853 select KALLSYMS_ALL
854 select STACKTRACE
855 select SCHEDSTATS
856 select SCHED_DEBUG
Heiko Carstensaa7d9352008-02-01 17:45:14 +0100857 depends on HAVE_LATENCYTOP_SUPPORT
Arjan van de Ven97455122008-01-25 21:08:34 +0100858 help
859 Enable this option if you want to use the LatencyTOP tool
860 to find out which userspace is blocking on what kernel operations.
861
Andi Kleen9e94cd32008-08-16 07:53:05 +0200862config SYSCTL_SYSCALL_CHECK
863 bool "Sysctl checks"
864 depends on SYSCTL_SYSCALL
865 ---help---
866 sys_sysctl uses binary paths that have been found challenging
867 to properly maintain and use. This enables checks that help
868 you to keep things correct.
869
Akinobu Mita6a11f752009-03-31 15:23:17 -0700870source mm/Kconfig.debug
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +0200871source kernel/trace/Kconfig
872
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100873config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +0100874 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100875 depends on PCI && X86
876 help
877 If you want to debug problems which hang or crash the kernel early
878 on boot and the crashing machine has a FireWire port, you can use
879 this feature to remotely access the memory of the crashed machine
880 over FireWire. This employs remote DMA as part of the OHCI1394
881 specification which is now the standard for FireWire controllers.
882
883 With remote DMA, you can monitor the printk buffer remotely using
884 firescope and access all memory below 4GB using fireproxy from gdb.
885 Even controlling a kernel debugger is possible using remote DMA.
886
887 Usage:
888
889 If ohci1394_dma=early is used as boot parameter, it will initialize
890 all OHCI1394 controllers which are found in the PCI config space.
891
892 As all changes to the FireWire bus such as enabling and disabling
893 devices cause a bus reset and thereby disable remote DMA for all
894 devices, be sure to have the cable plugged and FireWire enabled on
895 the debugging host before booting the debug target for debugging.
896
897 This code (~1k) is freed after boot. By then, the firewire stack
898 in charge of the OHCI-1394 controllers should be used instead.
899
900 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +0100901
Stefan Richter080de8c2008-02-28 20:54:43 +0100902config FIREWIRE_OHCI_REMOTE_DMA
903 bool "Remote debugging over FireWire with firewire-ohci"
904 depends on FIREWIRE_OHCI
905 help
906 This option lets you use the FireWire bus for remote debugging
907 with help of the firewire-ohci driver. It enables unfiltered
908 remote DMA in firewire-ohci.
909 See Documentation/debugging-via-ohci1394.txt for more information.
910
911 If unsure, say N.
912
Randy Dunlap152de302009-02-20 15:38:47 -0800913config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -0700914 bool "Build targets in Documentation/ tree"
915 depends on HEADERS_CHECK
916 help
917 This option attempts to build objects from the source files in the
918 kernel Documentation/ tree.
919
920 Say N if you are unsure.
921
Jason Barone9d376f2009-02-05 11:51:38 -0500922config DYNAMIC_DEBUG
Jason Baron86151fd2009-02-05 11:53:15 -0500923 bool "Enable dynamic printk() support"
Jason Baron346e15b2008-08-12 16:46:19 -0400924 default n
925 depends on PRINTK
Jason Baron86151fd2009-02-05 11:53:15 -0500926 depends on DEBUG_FS
Jason Baron346e15b2008-08-12 16:46:19 -0400927 help
928
929 Compiles debug level messages into the kernel, which would not
930 otherwise be available at runtime. These messages can then be
Jason Baron86151fd2009-02-05 11:53:15 -0500931 enabled/disabled based on various levels of scope - per source file,
932 function, module, format string, and line number. This mechanism
933 implicitly enables all pr_debug() and dev_dbg() calls. The impact of
934 this compile option is a larger kernel text size of about 2%.
Jason Baron346e15b2008-08-12 16:46:19 -0400935
936 Usage:
937
Jason Baron86151fd2009-02-05 11:53:15 -0500938 Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file,
939 which is contained in the 'debugfs' filesystem. Thus, the debugfs
940 filesystem must first be mounted before making use of this feature.
941 We refer the control file as: <debugfs>/dynamic_debug/ddebug. This
942 file contains a list of the debug statements that can be enabled. The
943 format for each line of the file is:
Jason Baron346e15b2008-08-12 16:46:19 -0400944
Jason Baron86151fd2009-02-05 11:53:15 -0500945 filename:lineno [module]function flags format
Jason Baron346e15b2008-08-12 16:46:19 -0400946
Jason Baron86151fd2009-02-05 11:53:15 -0500947 filename : source file of the debug statement
948 lineno : line number of the debug statement
949 module : module that contains the debug statement
950 function : function that contains the debug statement
951 flags : 'p' means the line is turned 'on' for printing
952 format : the format used for the debug statement
Jason Baron346e15b2008-08-12 16:46:19 -0400953
954 From a live system:
955
Jason Baron86151fd2009-02-05 11:53:15 -0500956 nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
957 # filename:lineno [module]function flags format
958 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
959 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
960 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
Jason Baron346e15b2008-08-12 16:46:19 -0400961
Jason Baron86151fd2009-02-05 11:53:15 -0500962 Example usage:
Jason Baron346e15b2008-08-12 16:46:19 -0400963
Jason Baron86151fd2009-02-05 11:53:15 -0500964 // enable the message at line 1603 of file svcsock.c
965 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
966 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400967
Jason Baron86151fd2009-02-05 11:53:15 -0500968 // enable all the messages in file svcsock.c
969 nullarbor:~ # echo -n 'file svcsock.c +p' >
970 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400971
Jason Baron86151fd2009-02-05 11:53:15 -0500972 // enable all the messages in the NFS server module
973 nullarbor:~ # echo -n 'module nfsd +p' >
974 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400975
Jason Baron86151fd2009-02-05 11:53:15 -0500976 // enable all 12 messages in the function svc_process()
977 nullarbor:~ # echo -n 'func svc_process +p' >
978 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400979
Jason Baron86151fd2009-02-05 11:53:15 -0500980 // disable all 12 messages in the function svc_process()
981 nullarbor:~ # echo -n 'func svc_process -p' >
982 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400983
Jason Baron86151fd2009-02-05 11:53:15 -0500984 See Documentation/dynamic-debug-howto.txt for additional information.
Jason Baron346e15b2008-08-12 16:46:19 -0400985
Joerg Roedel5ee00bd2009-01-09 12:14:24 +0100986config DMA_API_DEBUG
987 bool "Enable debugging of DMA-API usage"
988 depends on HAVE_DMA_API_DEBUG
989 help
990 Enable this option to debug the use of the DMA API by device drivers.
991 With this option you will be able to detect common bugs in device
992 drivers like double-freeing of DMA mappings or freeing mappings that
993 were never allocated.
994 This option causes a performance degredation. Use only if you want
995 to debug device drivers. If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -0400996
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700997source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +0200998
999source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001000
1001source "lib/Kconfig.kmemcheck"