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Linus Torvalds1da177e2005-04-16 15:20:36 -07001
2config PRINTK_TIME
3 bool "Show timing information on printks"
Randy Dunlapd3b8b6e2006-12-06 20:36:38 -08004 depends on PRINTK
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 help
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 Marinasa9d90582009-06-25 10:16:11 +0100362config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
363 int "Maximum kmemleak early log entries"
364 depends on DEBUG_KMEMLEAK
365 range 200 2000
366 default 400
367 help
368 Kmemleak must track all the memory allocations to avoid
369 reporting false positives. Since memory may be allocated or
370 freed before kmemleak is initialised, an early log buffer is
371 used to store these actions. If kmemleak reports "early log
372 buffer exceeded", please increase this value.
373
Catalin Marinas0822ee42009-06-11 13:24:14 +0100374config DEBUG_KMEMLEAK_TEST
375 tristate "Simple test for the kernel memory leak detector"
376 depends on DEBUG_KMEMLEAK
377 help
378 Say Y or M here to build a test for the kernel memory leak
379 detector. This option enables a module that explicitly leaks
380 memory.
381
382 If unsure, say N.
383
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384config DEBUG_PREEMPT
385 bool "Debug preemptible kernel"
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100386 depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 default y
388 help
389 If you say Y here then the kernel will use a debug variant of the
390 commonly used smp_processor_id() function and will print warnings
391 if kernel code uses it in a preemption-unsafe way. Also, the kernel
392 will detect preemption count underflows.
393
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700394config DEBUG_RT_MUTEXES
395 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700396 depends on DEBUG_KERNEL && RT_MUTEXES
397 help
398 This allows rt mutex semantics violations and rt mutex related
399 deadlocks (lockups) to be detected and reported automatically.
400
401config DEBUG_PI_LIST
402 bool
403 default y
404 depends on DEBUG_RT_MUTEXES
405
Thomas Gleixner61a87122006-06-27 02:54:56 -0700406config RT_MUTEX_TESTER
407 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700408 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700409 help
410 This option enables a rt-mutex tester.
411
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700413 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 depends on DEBUG_KERNEL
415 help
416 Say Y here and build SMP to catch missing spinlock initialization
417 and certain other kinds of spinlock errors commonly made. This is
418 best used in conjunction with the NMI watchdog so that spinlock
419 deadlocks are also debuggable.
420
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700421config DEBUG_MUTEXES
422 bool "Mutex debugging: basic checks"
423 depends on DEBUG_KERNEL
424 help
425 This feature allows mutex semantics violations to be detected and
426 reported.
427
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700428config DEBUG_LOCK_ALLOC
429 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700430 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700431 select DEBUG_SPINLOCK
432 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700433 select LOCKDEP
434 help
435 This feature will check whether any held lock (spinlock, rwlock,
436 mutex or rwsem) is incorrectly freed by the kernel, via any of the
437 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
438 vfree(), etc.), whether a live lock is incorrectly reinitialized via
439 spin_lock_init()/mutex_init()/etc., or whether there is any lock
440 held during task exit.
441
442config PROVE_LOCKING
443 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700444 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700445 select LOCKDEP
446 select DEBUG_SPINLOCK
447 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700448 select DEBUG_LOCK_ALLOC
449 default n
450 help
451 This feature enables the kernel to prove that all locking
452 that occurs in the kernel runtime is mathematically
453 correct: that under no circumstance could an arbitrary (and
454 not yet triggered) combination of observed locking
455 sequences (on an arbitrary number of CPUs, running an
456 arbitrary number of tasks and interrupt contexts) cause a
457 deadlock.
458
459 In short, this feature enables the kernel to report locking
460 related deadlocks before they actually occur.
461
462 The proof does not depend on how hard and complex a
463 deadlock scenario would be to trigger: how many
464 participant CPUs, tasks and irq-contexts would be needed
465 for it to trigger. The proof also does not depend on
466 timing: if a race and a resulting deadlock is possible
467 theoretically (no matter how unlikely the race scenario
468 is), it will be proven so and will immediately be
469 reported by the kernel (once the event is observed that
470 makes the deadlock theoretically possible).
471
472 If a deadlock is impossible (i.e. the locking rules, as
473 observed by the kernel, are mathematically correct), the
474 kernel reports nothing.
475
476 NOTE: this feature can also be enabled for rwlocks, mutexes
477 and rwsems - in which case all dependencies between these
478 different locking variants are observed and mapped too, and
479 the proof of observed correctness is also maintained for an
480 arbitrary combination of these separate locking variants.
481
482 For more details, see Documentation/lockdep-design.txt.
483
484config LOCKDEP
485 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700486 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700487 select STACKTRACE
Peter Zijlstra00540e52009-06-12 10:04:01 +0200488 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700489 select KALLSYMS
490 select KALLSYMS_ALL
491
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700492config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700493 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700494 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
495 select LOCKDEP
496 select DEBUG_SPINLOCK
497 select DEBUG_MUTEXES
498 select DEBUG_LOCK_ALLOC
499 default n
500 help
501 This feature enables tracking lock contention points
502
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700503 For more details, see Documentation/lockstat.txt
504
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700505config DEBUG_LOCKDEP
506 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700507 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700508 help
509 If you say Y here, the lock dependency engine will do
510 additional runtime checks to debug itself, at the price
511 of more runtime overhead.
512
513config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700514 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700515 bool
516 default y
517 depends on TRACE_IRQFLAGS_SUPPORT
518 depends on PROVE_LOCKING
519
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700521 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 depends on DEBUG_KERNEL
523 help
524 If you say Y here, various routines which may sleep will become very
525 noisy if they are called with a spinlock held.
526
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700527config DEBUG_LOCKING_API_SELFTESTS
528 bool "Locking API boot-time self-tests"
529 depends on DEBUG_KERNEL
530 help
531 Say Y here if you want the kernel to run a short self-test during
532 bootup. The self-test checks whether common types of locking bugs
533 are detected by debugging mechanisms or not. (if you disable
534 lock debugging then those bugs wont be detected of course.)
535 The following locking APIs are covered: spinlocks, rwlocks,
536 mutexes and rwsems.
537
Ingo Molnar8637c092006-07-03 00:24:38 -0700538config STACKTRACE
539 bool
540 depends on STACKTRACE_SUPPORT
541
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542config DEBUG_KOBJECT
543 bool "kobject debugging"
544 depends on DEBUG_KERNEL
545 help
546 If you say Y here, some extra kobject debugging messages will be sent
547 to the syslog.
548
549config DEBUG_HIGHMEM
550 bool "Highmem debugging"
551 depends on DEBUG_KERNEL && HIGHMEM
552 help
553 This options enables addition error checking for high memory systems.
554 Disable for production systems.
555
556config DEBUG_BUGVERBOSE
557 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700558 depends on BUG
David Howellsb920de12008-02-08 04:19:31 -0800559 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
560 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 default !EMBEDDED
562 help
563 Say Y here to make BUG() panics output the file name and line number
564 of the BUG call as well as the EIP and oops trace. This aids
565 debugging but costs about 70-100K of memory.
566
567config DEBUG_INFO
568 bool "Compile the kernel with debug info"
569 depends on DEBUG_KERNEL
570 help
571 If you say Y here the resulting kernel image will include
572 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600573 This adds debug symbols to the kernel and modules (gcc -g), and
574 is needed if you intend to use kernel crashdump or binary object
575 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576 Say Y here only if you plan to debug the kernel.
577
578 If unsure, say N.
579
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800580config DEBUG_VM
581 bool "Debug VM"
582 depends on DEBUG_KERNEL
583 help
Nick Piggin13e74442006-01-06 00:10:58 -0800584 Enable this to turn on extended checks in the virtual-memory system
585 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800586
587 If unsure, say N.
588
Jiri Slaby59ea7462008-06-12 13:56:40 +0200589config DEBUG_VIRTUAL
590 bool "Debug VM translations"
591 depends on DEBUG_KERNEL && X86
592 help
593 Enable some costly sanity checks in virtual to page code. This can
594 catch mistakes with virt_to_page() and friends.
595
596 If unsure, say N.
597
David Howells8feae132009-01-08 12:04:47 +0000598config DEBUG_NOMMU_REGIONS
599 bool "Debug the global anon/private NOMMU mapping region tree"
600 depends on DEBUG_KERNEL && !MMU
601 help
602 This option causes the global tree of anonymous and private mapping
603 regions to be regularly checked for invalid topology.
604
Dave Hansenad775f52008-02-15 14:38:01 -0800605config DEBUG_WRITECOUNT
606 bool "Debug filesystem writers count"
607 depends on DEBUG_KERNEL
608 help
609 Enable this to catch wrong use of the writers count in struct
610 vfsmount. This will increase the size of each file struct by
611 32 bits.
612
613 If unsure, say N.
614
Mel Gorman6b74ab92008-07-23 21:26:49 -0700615config DEBUG_MEMORY_INIT
616 bool "Debug memory initialisation" if EMBEDDED
617 default !EMBEDDED
618 help
619 Enable this for additional checks during memory initialisation.
620 The sanity checks verify aspects of the VM such as the memory model
621 and other information provided by the architecture. Verbose
622 information will be printed at KERN_DEBUG loglevel depending
623 on the mminit_loglevel= command-line option.
624
625 If unsure, say Y
626
Dave Jones199a9af2006-09-29 01:59:00 -0700627config DEBUG_LIST
628 bool "Debug linked list manipulation"
629 depends on DEBUG_KERNEL
630 help
631 Enable this to turn on extended checks in the linked-list
632 walking routines.
633
634 If unsure, say N.
635
Jens Axboed6ec0842007-10-22 20:01:06 +0200636config DEBUG_SG
637 bool "Debug SG table operations"
638 depends on DEBUG_KERNEL
639 help
640 Enable this to turn on checks on scatter-gather tables. This can
641 help find problems with drivers that do not properly initialize
642 their sg tables.
643
644 If unsure, say N.
645
Arjan van de Ven1b2439d2008-08-15 15:29:38 -0700646config DEBUG_NOTIFIERS
647 bool "Debug notifier call chains"
648 depends on DEBUG_KERNEL
649 help
650 Enable this to turn on sanity checking for notifier call chains.
651 This is most useful for kernel developers to make sure that
652 modules properly unregister themselves from notifier chains.
653 This is a relatively cheap check but if you care about maximum
654 performance, say N.
655
David Howellse0e81732009-09-02 09:13:40 +0100656config DEBUG_CREDENTIALS
657 bool "Debug credential management"
658 depends on DEBUG_KERNEL
659 help
660 Enable this to turn on some debug checking for credential
661 management. The additional code keeps track of the number of
662 pointers from task_structs to any given cred struct, and checks to
663 see that this number never exceeds the usage count of the cred
664 struct.
665
666 Furthermore, if SELinux is enabled, this also checks that the
667 security pointer in the cred struct is never seen to be invalid.
668
669 If unsure, say N.
670
Jeff Mahoney64dec402009-01-16 13:23:35 -0500671#
672# Select this config option from the architecture Kconfig, if it
673# it is preferred to always offer frame pointers as a config
674# option on the architecture (regardless of KERNEL_DEBUG):
675#
676config ARCH_WANT_FRAME_POINTERS
677 bool
678 help
679
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680config FRAME_POINTER
681 bool "Compile the kernel with frame pointers"
David Howellsb920de12008-02-08 04:19:31 -0800682 depends on DEBUG_KERNEL && \
Heiko Carstens75ee0342009-04-23 13:58:10 +0200683 (CRIS || M68K || M68KNOMMU || FRV || UML || \
Ingo Molnarda4276b2009-01-07 11:05:10 +0100684 AVR32 || SUPERH || BLACKFIN || MN10300) || \
685 ARCH_WANT_FRAME_POINTERS
686 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 help
Ingo Molnarda4276b2009-01-07 11:05:10 +0100688 If you say Y here the resulting kernel image will be slightly
689 larger and slower, but it gives very useful debugging information
690 in case of kernel bugs. (precise oopses/stacktraces/warnings)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700692config BOOT_PRINTK_DELAY
693 bool "Delay each boot printk message by N milliseconds"
694 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
695 help
696 This build option allows you to read kernel boot messages
697 by inserting a short delay after each one. The delay is
698 specified in milliseconds on the kernel command line,
699 using "boot_delay=N".
700
701 It is likely that you would also need to use "lpj=M" to preset
702 the "loops per jiffie" value.
703 See a previous boot log for the "lpj" value to use for your
704 system, and then set "lpj=M" before setting "boot_delay=N".
705 NOTE: Using this option may adversely affect SMP systems.
706 I.e., processors other than the first one may not boot up.
707 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
708 what it believes to be lockup conditions.
709
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800710config RCU_TORTURE_TEST
711 tristate "torture tests for RCU"
712 depends on DEBUG_KERNEL
713 default n
714 help
715 This option provides a kernel module that runs torture tests
716 on the RCU infrastructure. The kernel module may be built
717 after the fact on the running kernel to be tested, if desired.
718
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700719 Say Y here if you want RCU torture tests to be built into
720 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800721 Say M if you want the RCU torture tests to build as a module.
722 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700723
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700724config RCU_TORTURE_TEST_RUNNABLE
725 bool "torture tests for RCU runnable by default"
726 depends on RCU_TORTURE_TEST = y
727 default n
728 help
729 This option provides a way to build the RCU torture tests
730 directly into the kernel without them starting up at boot
731 time. You can use /proc/sys/kernel/rcutorture_runnable
732 to manually override this setting. This /proc file is
733 available only when the RCU torture tests have been built
734 into the kernel.
735
736 Say Y here if you want the RCU torture tests to start during
737 boot (you probably don't).
738 Say N here if you want the RCU torture tests to start only
739 after being manually enabled via /proc.
740
Paul E. McKenney2133b5d2008-10-02 16:06:39 -0700741config RCU_CPU_STALL_DETECTOR
Paul E. McKenney67182ae2008-08-10 18:35:38 -0700742 bool "Check for stalled CPUs delaying RCU grace periods"
Paul E. McKenney6b3ef482009-08-22 13:56:53 -0700743 depends on TREE_RCU || TREE_PREEMPT_RCU
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100744 default n
745 help
746 This option causes RCU to printk information on which
747 CPUs are delaying the current grace period, but only when
748 the grace period extends for excessive time periods.
749
750 Say Y if you want RCU to perform such checks.
751
752 Say N if you are unsure.
753
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +0100754config KPROBES_SANITY_TEST
755 bool "Kprobes sanity tests"
756 depends on DEBUG_KERNEL
757 depends on KPROBES
758 default n
759 help
760 This option provides for testing basic kprobes functionality on
761 boot. A sample kprobe, jprobe and kretprobe are inserted and
762 verified for functionality.
763
764 Say N if you are unsure.
765
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100766config BACKTRACE_SELF_TEST
767 tristate "Self test for the backtrace code"
768 depends on DEBUG_KERNEL
769 default n
770 help
771 This option provides a kernel module that can be used to test
772 the kernel stack backtrace code. This option is not useful
773 for distributions or general kernels, but only for kernel
774 developers working on architecture code.
775
Vegard Nossumad118c52008-06-27 18:04:48 +0200776 Note that if you want to also test saved backtraces, you will
777 have to enable STACKTRACE as well.
778
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100779 Say N if you are unsure.
780
Tejun Heo870d6652008-08-25 19:47:25 +0900781config DEBUG_BLOCK_EXT_DEVT
782 bool "Force extended block device numbers and spread them"
783 depends on DEBUG_KERNEL
784 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +0200785 default n
Tejun Heo870d6652008-08-25 19:47:25 +0900786 help
Tejun Heo0e11e342008-10-13 10:46:01 +0200787 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
788 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
789 YOU ARE DOING. Distros, please enable this and fix whatever
790 is broken.
791
Tejun Heo870d6652008-08-25 19:47:25 +0900792 Conventionally, block device numbers are allocated from
793 predetermined contiguous area. However, extended block area
794 may introduce non-contiguous block device numbers. This
795 option forces most block device numbers to be allocated from
796 the extended space and spreads them to discover kernel or
797 userland code paths which assume predetermined contiguous
798 device number allocation.
799
Tejun Heo55dc7db2008-09-01 13:44:35 +0200800 Note that turning on this debug option shuffles all the
801 device numbers for all IDE and SCSI devices including libata
802 ones, so root partition specified using device number
803 directly (via rdev or root=MAJ:MIN) won't work anymore.
804 Textual device names (root=/dev/sdXn) will continue to work.
805
Tejun Heo870d6652008-08-25 19:47:25 +0900806 Say N if you are unsure.
807
Ankita Garg8bb31b92006-10-02 02:17:36 -0700808config LKDTM
809 tristate "Linux Kernel Dump Test Tool Module"
Don Mullisbf4735a2006-12-10 02:18:37 -0800810 depends on DEBUG_KERNEL
Ankita Garg8bb31b92006-10-02 02:17:36 -0700811 depends on KPROBES
Chris Snookfddd9cf2008-02-23 15:23:26 -0800812 depends on BLOCK
Ankita Garg8bb31b92006-10-02 02:17:36 -0700813 default n
814 help
815 This module enables testing of the different dumping mechanisms by
816 inducing system failures at predefined crash points.
817 If you don't need it: say N
818 Choose M here to compile this code as a module. The module will be
819 called lkdtm.
820
821 Documentation on how to use the module can be found in
822 drivers/misc/lkdtm.c
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800823
824config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800825 bool "Fault-injection framework"
826 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -0800827 help
828 Provide fault-injection framework.
829 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800830
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800831config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800832 bool "Fault-injection capability for kmalloc"
833 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +0900834 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800835 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800836 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800837
Akinobu Mita933e3122006-12-08 02:39:45 -0800838config FAIL_PAGE_ALLOC
839 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800840 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800841 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800842 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800843
Akinobu Mitac17bb492006-12-08 02:39:46 -0800844config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100845 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -0700846 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -0800847 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800848 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800849
Jens Axboe581d4e22008-09-14 05:56:33 -0700850config FAIL_IO_TIMEOUT
851 bool "Faul-injection capability for faking disk interrupts"
852 depends on FAULT_INJECTION && BLOCK
853 help
854 Provide fault-injection capability on end IO handling. This
855 will make the block layer "forget" an interrupt as configured,
856 thus exercising the error handling.
857
858 Only works with drivers that use the generic timeout handling,
859 for others it wont do anything.
860
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800861config FAULT_INJECTION_DEBUG_FS
862 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800863 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800864 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800865 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -0800866
867config FAULT_INJECTION_STACKTRACE_FILTER
868 bool "stacktrace filter for fault-injection capabilities"
869 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -0700870 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -0800871 select STACKTRACE
Heiko Carstens75ee0342009-04-23 13:58:10 +0200872 select FRAME_POINTER if !PPC && !S390
Akinobu Mita1df49002007-02-20 13:57:56 -0800873 help
874 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700875
Arjan van de Ven97455122008-01-25 21:08:34 +0100876config LATENCYTOP
877 bool "Latency measuring infrastructure"
Heiko Carstens75ee0342009-04-23 13:58:10 +0200878 select FRAME_POINTER if !MIPS && !PPC && !S390
Arjan van de Ven97455122008-01-25 21:08:34 +0100879 select KALLSYMS
880 select KALLSYMS_ALL
881 select STACKTRACE
882 select SCHEDSTATS
883 select SCHED_DEBUG
Heiko Carstensaa7d9352008-02-01 17:45:14 +0100884 depends on HAVE_LATENCYTOP_SUPPORT
Arjan van de Ven97455122008-01-25 21:08:34 +0100885 help
886 Enable this option if you want to use the LatencyTOP tool
887 to find out which userspace is blocking on what kernel operations.
888
Andi Kleen9e94cd32008-08-16 07:53:05 +0200889config SYSCTL_SYSCALL_CHECK
890 bool "Sysctl checks"
891 depends on SYSCTL_SYSCALL
892 ---help---
893 sys_sysctl uses binary paths that have been found challenging
894 to properly maintain and use. This enables checks that help
895 you to keep things correct.
896
Akinobu Mita6a11f752009-03-31 15:23:17 -0700897source mm/Kconfig.debug
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +0200898source kernel/trace/Kconfig
899
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100900config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +0100901 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100902 depends on PCI && X86
903 help
904 If you want to debug problems which hang or crash the kernel early
905 on boot and the crashing machine has a FireWire port, you can use
906 this feature to remotely access the memory of the crashed machine
907 over FireWire. This employs remote DMA as part of the OHCI1394
908 specification which is now the standard for FireWire controllers.
909
910 With remote DMA, you can monitor the printk buffer remotely using
911 firescope and access all memory below 4GB using fireproxy from gdb.
912 Even controlling a kernel debugger is possible using remote DMA.
913
914 Usage:
915
916 If ohci1394_dma=early is used as boot parameter, it will initialize
917 all OHCI1394 controllers which are found in the PCI config space.
918
919 As all changes to the FireWire bus such as enabling and disabling
920 devices cause a bus reset and thereby disable remote DMA for all
921 devices, be sure to have the cable plugged and FireWire enabled on
922 the debugging host before booting the debug target for debugging.
923
924 This code (~1k) is freed after boot. By then, the firewire stack
925 in charge of the OHCI-1394 controllers should be used instead.
926
927 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +0100928
Stefan Richter080de8c2008-02-28 20:54:43 +0100929config FIREWIRE_OHCI_REMOTE_DMA
930 bool "Remote debugging over FireWire with firewire-ohci"
931 depends on FIREWIRE_OHCI
932 help
933 This option lets you use the FireWire bus for remote debugging
934 with help of the firewire-ohci driver. It enables unfiltered
935 remote DMA in firewire-ohci.
936 See Documentation/debugging-via-ohci1394.txt for more information.
937
938 If unsure, say N.
939
Randy Dunlap152de302009-02-20 15:38:47 -0800940config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -0700941 bool "Build targets in Documentation/ tree"
942 depends on HEADERS_CHECK
943 help
944 This option attempts to build objects from the source files in the
945 kernel Documentation/ tree.
946
947 Say N if you are unsure.
948
Jason Barone9d376f2009-02-05 11:51:38 -0500949config DYNAMIC_DEBUG
Jason Baron86151fd2009-02-05 11:53:15 -0500950 bool "Enable dynamic printk() support"
Jason Baron346e15b2008-08-12 16:46:19 -0400951 default n
952 depends on PRINTK
Jason Baron86151fd2009-02-05 11:53:15 -0500953 depends on DEBUG_FS
Jason Baron346e15b2008-08-12 16:46:19 -0400954 help
955
956 Compiles debug level messages into the kernel, which would not
957 otherwise be available at runtime. These messages can then be
Jason Baron86151fd2009-02-05 11:53:15 -0500958 enabled/disabled based on various levels of scope - per source file,
959 function, module, format string, and line number. This mechanism
960 implicitly enables all pr_debug() and dev_dbg() calls. The impact of
961 this compile option is a larger kernel text size of about 2%.
Jason Baron346e15b2008-08-12 16:46:19 -0400962
963 Usage:
964
Jason Baron86151fd2009-02-05 11:53:15 -0500965 Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file,
966 which is contained in the 'debugfs' filesystem. Thus, the debugfs
967 filesystem must first be mounted before making use of this feature.
968 We refer the control file as: <debugfs>/dynamic_debug/ddebug. This
969 file contains a list of the debug statements that can be enabled. The
970 format for each line of the file is:
Jason Baron346e15b2008-08-12 16:46:19 -0400971
Jason Baron86151fd2009-02-05 11:53:15 -0500972 filename:lineno [module]function flags format
Jason Baron346e15b2008-08-12 16:46:19 -0400973
Jason Baron86151fd2009-02-05 11:53:15 -0500974 filename : source file of the debug statement
975 lineno : line number of the debug statement
976 module : module that contains the debug statement
977 function : function that contains the debug statement
978 flags : 'p' means the line is turned 'on' for printing
979 format : the format used for the debug statement
Jason Baron346e15b2008-08-12 16:46:19 -0400980
981 From a live system:
982
Jason Baron86151fd2009-02-05 11:53:15 -0500983 nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
984 # filename:lineno [module]function flags format
985 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
986 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
987 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
Jason Baron346e15b2008-08-12 16:46:19 -0400988
Jason Baron86151fd2009-02-05 11:53:15 -0500989 Example usage:
Jason Baron346e15b2008-08-12 16:46:19 -0400990
Jason Baron86151fd2009-02-05 11:53:15 -0500991 // enable the message at line 1603 of file svcsock.c
992 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
993 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400994
Jason Baron86151fd2009-02-05 11:53:15 -0500995 // enable all the messages in file svcsock.c
996 nullarbor:~ # echo -n 'file svcsock.c +p' >
997 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400998
Jason Baron86151fd2009-02-05 11:53:15 -0500999 // enable all the messages in the NFS server module
1000 nullarbor:~ # echo -n 'module nfsd +p' >
1001 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001002
Jason Baron86151fd2009-02-05 11:53:15 -05001003 // enable all 12 messages in the function svc_process()
1004 nullarbor:~ # echo -n 'func svc_process +p' >
1005 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001006
Jason Baron86151fd2009-02-05 11:53:15 -05001007 // disable all 12 messages in the function svc_process()
1008 nullarbor:~ # echo -n 'func svc_process -p' >
1009 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001010
Jason Baron86151fd2009-02-05 11:53:15 -05001011 See Documentation/dynamic-debug-howto.txt for additional information.
Jason Baron346e15b2008-08-12 16:46:19 -04001012
Joerg Roedel5ee00bd2009-01-09 12:14:24 +01001013config DMA_API_DEBUG
1014 bool "Enable debugging of DMA-API usage"
1015 depends on HAVE_DMA_API_DEBUG
1016 help
1017 Enable this option to debug the use of the DMA API by device drivers.
1018 With this option you will be able to detect common bugs in device
1019 drivers like double-freeing of DMA mappings or freeing mappings that
1020 were never allocated.
1021 This option causes a performance degredation. Use only if you want
1022 to debug device drivers. If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -04001023
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001024source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02001025
1026source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001027
1028source "lib/Kconfig.kmemcheck"