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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"
Ingo Molnar50dd26ba2006-01-08 01:01:42 -0800303 depends on DEBUG_KERNEL && SLAB
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"
315 depends on SLUB && SLUB_DEBUG
316 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339config DEBUG_PREEMPT
340 bool "Debug preemptible kernel"
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100341 depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 default y
343 help
344 If you say Y here then the kernel will use a debug variant of the
345 commonly used smp_processor_id() function and will print warnings
346 if kernel code uses it in a preemption-unsafe way. Also, the kernel
347 will detect preemption count underflows.
348
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700349config DEBUG_RT_MUTEXES
350 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700351 depends on DEBUG_KERNEL && RT_MUTEXES
352 help
353 This allows rt mutex semantics violations and rt mutex related
354 deadlocks (lockups) to be detected and reported automatically.
355
356config DEBUG_PI_LIST
357 bool
358 default y
359 depends on DEBUG_RT_MUTEXES
360
Thomas Gleixner61a87122006-06-27 02:54:56 -0700361config RT_MUTEX_TESTER
362 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700363 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700364 help
365 This option enables a rt-mutex tester.
366
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700368 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 depends on DEBUG_KERNEL
370 help
371 Say Y here and build SMP to catch missing spinlock initialization
372 and certain other kinds of spinlock errors commonly made. This is
373 best used in conjunction with the NMI watchdog so that spinlock
374 deadlocks are also debuggable.
375
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700376config DEBUG_MUTEXES
377 bool "Mutex debugging: basic checks"
378 depends on DEBUG_KERNEL
379 help
380 This feature allows mutex semantics violations to be detected and
381 reported.
382
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700383config DEBUG_LOCK_ALLOC
384 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700385 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700386 select DEBUG_SPINLOCK
387 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700388 select LOCKDEP
389 help
390 This feature will check whether any held lock (spinlock, rwlock,
391 mutex or rwsem) is incorrectly freed by the kernel, via any of the
392 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
393 vfree(), etc.), whether a live lock is incorrectly reinitialized via
394 spin_lock_init()/mutex_init()/etc., or whether there is any lock
395 held during task exit.
396
397config PROVE_LOCKING
398 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700399 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700400 select LOCKDEP
401 select DEBUG_SPINLOCK
402 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700403 select DEBUG_LOCK_ALLOC
404 default n
405 help
406 This feature enables the kernel to prove that all locking
407 that occurs in the kernel runtime is mathematically
408 correct: that under no circumstance could an arbitrary (and
409 not yet triggered) combination of observed locking
410 sequences (on an arbitrary number of CPUs, running an
411 arbitrary number of tasks and interrupt contexts) cause a
412 deadlock.
413
414 In short, this feature enables the kernel to report locking
415 related deadlocks before they actually occur.
416
417 The proof does not depend on how hard and complex a
418 deadlock scenario would be to trigger: how many
419 participant CPUs, tasks and irq-contexts would be needed
420 for it to trigger. The proof also does not depend on
421 timing: if a race and a resulting deadlock is possible
422 theoretically (no matter how unlikely the race scenario
423 is), it will be proven so and will immediately be
424 reported by the kernel (once the event is observed that
425 makes the deadlock theoretically possible).
426
427 If a deadlock is impossible (i.e. the locking rules, as
428 observed by the kernel, are mathematically correct), the
429 kernel reports nothing.
430
431 NOTE: this feature can also be enabled for rwlocks, mutexes
432 and rwsems - in which case all dependencies between these
433 different locking variants are observed and mapped too, and
434 the proof of observed correctness is also maintained for an
435 arbitrary combination of these separate locking variants.
436
437 For more details, see Documentation/lockdep-design.txt.
438
439config LOCKDEP
440 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700441 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700442 select STACKTRACE
Heiko Carstens75ee0342009-04-23 13:58:10 +0200443 select FRAME_POINTER if !X86 && !MIPS && !PPC && !ARM_UNWIND && !S390
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700444 select KALLSYMS
445 select KALLSYMS_ALL
446
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700447config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700448 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700449 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
450 select LOCKDEP
451 select DEBUG_SPINLOCK
452 select DEBUG_MUTEXES
453 select DEBUG_LOCK_ALLOC
454 default n
455 help
456 This feature enables tracking lock contention points
457
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700458 For more details, see Documentation/lockstat.txt
459
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700460config DEBUG_LOCKDEP
461 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700462 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700463 help
464 If you say Y here, the lock dependency engine will do
465 additional runtime checks to debug itself, at the price
466 of more runtime overhead.
467
468config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700469 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700470 bool
471 default y
472 depends on TRACE_IRQFLAGS_SUPPORT
473 depends on PROVE_LOCKING
474
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700476 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 depends on DEBUG_KERNEL
478 help
479 If you say Y here, various routines which may sleep will become very
480 noisy if they are called with a spinlock held.
481
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700482config DEBUG_LOCKING_API_SELFTESTS
483 bool "Locking API boot-time self-tests"
484 depends on DEBUG_KERNEL
485 help
486 Say Y here if you want the kernel to run a short self-test during
487 bootup. The self-test checks whether common types of locking bugs
488 are detected by debugging mechanisms or not. (if you disable
489 lock debugging then those bugs wont be detected of course.)
490 The following locking APIs are covered: spinlocks, rwlocks,
491 mutexes and rwsems.
492
Ingo Molnar8637c092006-07-03 00:24:38 -0700493config STACKTRACE
494 bool
495 depends on STACKTRACE_SUPPORT
496
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497config DEBUG_KOBJECT
498 bool "kobject debugging"
499 depends on DEBUG_KERNEL
500 help
501 If you say Y here, some extra kobject debugging messages will be sent
502 to the syslog.
503
504config DEBUG_HIGHMEM
505 bool "Highmem debugging"
506 depends on DEBUG_KERNEL && HIGHMEM
507 help
508 This options enables addition error checking for high memory systems.
509 Disable for production systems.
510
511config DEBUG_BUGVERBOSE
512 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700513 depends on BUG
David Howellsb920de12008-02-08 04:19:31 -0800514 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
515 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 default !EMBEDDED
517 help
518 Say Y here to make BUG() panics output the file name and line number
519 of the BUG call as well as the EIP and oops trace. This aids
520 debugging but costs about 70-100K of memory.
521
522config DEBUG_INFO
523 bool "Compile the kernel with debug info"
524 depends on DEBUG_KERNEL
525 help
526 If you say Y here the resulting kernel image will include
527 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600528 This adds debug symbols to the kernel and modules (gcc -g), and
529 is needed if you intend to use kernel crashdump or binary object
530 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 Say Y here only if you plan to debug the kernel.
532
533 If unsure, say N.
534
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800535config DEBUG_VM
536 bool "Debug VM"
537 depends on DEBUG_KERNEL
538 help
Nick Piggin13e74442006-01-06 00:10:58 -0800539 Enable this to turn on extended checks in the virtual-memory system
540 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800541
542 If unsure, say N.
543
Jiri Slaby59ea7462008-06-12 13:56:40 +0200544config DEBUG_VIRTUAL
545 bool "Debug VM translations"
546 depends on DEBUG_KERNEL && X86
547 help
548 Enable some costly sanity checks in virtual to page code. This can
549 catch mistakes with virt_to_page() and friends.
550
551 If unsure, say N.
552
David Howells8feae132009-01-08 12:04:47 +0000553config DEBUG_NOMMU_REGIONS
554 bool "Debug the global anon/private NOMMU mapping region tree"
555 depends on DEBUG_KERNEL && !MMU
556 help
557 This option causes the global tree of anonymous and private mapping
558 regions to be regularly checked for invalid topology.
559
Dave Hansenad775f52008-02-15 14:38:01 -0800560config DEBUG_WRITECOUNT
561 bool "Debug filesystem writers count"
562 depends on DEBUG_KERNEL
563 help
564 Enable this to catch wrong use of the writers count in struct
565 vfsmount. This will increase the size of each file struct by
566 32 bits.
567
568 If unsure, say N.
569
Mel Gorman6b74ab92008-07-23 21:26:49 -0700570config DEBUG_MEMORY_INIT
571 bool "Debug memory initialisation" if EMBEDDED
572 default !EMBEDDED
573 help
574 Enable this for additional checks during memory initialisation.
575 The sanity checks verify aspects of the VM such as the memory model
576 and other information provided by the architecture. Verbose
577 information will be printed at KERN_DEBUG loglevel depending
578 on the mminit_loglevel= command-line option.
579
580 If unsure, say Y
581
Dave Jones199a9af2006-09-29 01:59:00 -0700582config DEBUG_LIST
583 bool "Debug linked list manipulation"
584 depends on DEBUG_KERNEL
585 help
586 Enable this to turn on extended checks in the linked-list
587 walking routines.
588
589 If unsure, say N.
590
Jens Axboed6ec0842007-10-22 20:01:06 +0200591config DEBUG_SG
592 bool "Debug SG table operations"
593 depends on DEBUG_KERNEL
594 help
595 Enable this to turn on checks on scatter-gather tables. This can
596 help find problems with drivers that do not properly initialize
597 their sg tables.
598
599 If unsure, say N.
600
Arjan van de Ven1b2439d2008-08-15 15:29:38 -0700601config DEBUG_NOTIFIERS
602 bool "Debug notifier call chains"
603 depends on DEBUG_KERNEL
604 help
605 Enable this to turn on sanity checking for notifier call chains.
606 This is most useful for kernel developers to make sure that
607 modules properly unregister themselves from notifier chains.
608 This is a relatively cheap check but if you care about maximum
609 performance, say N.
610
Jeff Mahoney64dec402009-01-16 13:23:35 -0500611#
612# Select this config option from the architecture Kconfig, if it
613# it is preferred to always offer frame pointers as a config
614# option on the architecture (regardless of KERNEL_DEBUG):
615#
616config ARCH_WANT_FRAME_POINTERS
617 bool
618 help
619
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620config FRAME_POINTER
621 bool "Compile the kernel with frame pointers"
David Howellsb920de12008-02-08 04:19:31 -0800622 depends on DEBUG_KERNEL && \
Heiko Carstens75ee0342009-04-23 13:58:10 +0200623 (CRIS || M68K || M68KNOMMU || FRV || UML || \
Ingo Molnarda4276b2009-01-07 11:05:10 +0100624 AVR32 || SUPERH || BLACKFIN || MN10300) || \
625 ARCH_WANT_FRAME_POINTERS
626 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627 help
Ingo Molnarda4276b2009-01-07 11:05:10 +0100628 If you say Y here the resulting kernel image will be slightly
629 larger and slower, but it gives very useful debugging information
630 in case of kernel bugs. (precise oopses/stacktraces/warnings)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700632config BOOT_PRINTK_DELAY
633 bool "Delay each boot printk message by N milliseconds"
634 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
635 help
636 This build option allows you to read kernel boot messages
637 by inserting a short delay after each one. The delay is
638 specified in milliseconds on the kernel command line,
639 using "boot_delay=N".
640
641 It is likely that you would also need to use "lpj=M" to preset
642 the "loops per jiffie" value.
643 See a previous boot log for the "lpj" value to use for your
644 system, and then set "lpj=M" before setting "boot_delay=N".
645 NOTE: Using this option may adversely affect SMP systems.
646 I.e., processors other than the first one may not boot up.
647 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
648 what it believes to be lockup conditions.
649
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800650config RCU_TORTURE_TEST
651 tristate "torture tests for RCU"
652 depends on DEBUG_KERNEL
653 default n
654 help
655 This option provides a kernel module that runs torture tests
656 on the RCU infrastructure. The kernel module may be built
657 after the fact on the running kernel to be tested, if desired.
658
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700659 Say Y here if you want RCU torture tests to be built into
660 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800661 Say M if you want the RCU torture tests to build as a module.
662 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700663
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700664config RCU_TORTURE_TEST_RUNNABLE
665 bool "torture tests for RCU runnable by default"
666 depends on RCU_TORTURE_TEST = y
667 default n
668 help
669 This option provides a way to build the RCU torture tests
670 directly into the kernel without them starting up at boot
671 time. You can use /proc/sys/kernel/rcutorture_runnable
672 to manually override this setting. This /proc file is
673 available only when the RCU torture tests have been built
674 into the kernel.
675
676 Say Y here if you want the RCU torture tests to start during
677 boot (you probably don't).
678 Say N here if you want the RCU torture tests to start only
679 after being manually enabled via /proc.
680
Paul E. McKenney2133b5d2008-10-02 16:06:39 -0700681config RCU_CPU_STALL_DETECTOR
Paul E. McKenney67182ae2008-08-10 18:35:38 -0700682 bool "Check for stalled CPUs delaying RCU grace periods"
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100683 depends on CLASSIC_RCU || TREE_RCU
684 default n
685 help
686 This option causes RCU to printk information on which
687 CPUs are delaying the current grace period, but only when
688 the grace period extends for excessive time periods.
689
690 Say Y if you want RCU to perform such checks.
691
692 Say N if you are unsure.
693
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +0100694config KPROBES_SANITY_TEST
695 bool "Kprobes sanity tests"
696 depends on DEBUG_KERNEL
697 depends on KPROBES
698 default n
699 help
700 This option provides for testing basic kprobes functionality on
701 boot. A sample kprobe, jprobe and kretprobe are inserted and
702 verified for functionality.
703
704 Say N if you are unsure.
705
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100706config BACKTRACE_SELF_TEST
707 tristate "Self test for the backtrace code"
708 depends on DEBUG_KERNEL
709 default n
710 help
711 This option provides a kernel module that can be used to test
712 the kernel stack backtrace code. This option is not useful
713 for distributions or general kernels, but only for kernel
714 developers working on architecture code.
715
Vegard Nossumad118c52008-06-27 18:04:48 +0200716 Note that if you want to also test saved backtraces, you will
717 have to enable STACKTRACE as well.
718
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100719 Say N if you are unsure.
720
Tejun Heo870d6652008-08-25 19:47:25 +0900721config DEBUG_BLOCK_EXT_DEVT
722 bool "Force extended block device numbers and spread them"
723 depends on DEBUG_KERNEL
724 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +0200725 default n
Tejun Heo870d6652008-08-25 19:47:25 +0900726 help
Tejun Heo0e11e342008-10-13 10:46:01 +0200727 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
728 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
729 YOU ARE DOING. Distros, please enable this and fix whatever
730 is broken.
731
Tejun Heo870d6652008-08-25 19:47:25 +0900732 Conventionally, block device numbers are allocated from
733 predetermined contiguous area. However, extended block area
734 may introduce non-contiguous block device numbers. This
735 option forces most block device numbers to be allocated from
736 the extended space and spreads them to discover kernel or
737 userland code paths which assume predetermined contiguous
738 device number allocation.
739
Tejun Heo55dc7db2008-09-01 13:44:35 +0200740 Note that turning on this debug option shuffles all the
741 device numbers for all IDE and SCSI devices including libata
742 ones, so root partition specified using device number
743 directly (via rdev or root=MAJ:MIN) won't work anymore.
744 Textual device names (root=/dev/sdXn) will continue to work.
745
Tejun Heo870d6652008-08-25 19:47:25 +0900746 Say N if you are unsure.
747
Ankita Garg8bb31b92006-10-02 02:17:36 -0700748config LKDTM
749 tristate "Linux Kernel Dump Test Tool Module"
Don Mullisbf4735a2006-12-10 02:18:37 -0800750 depends on DEBUG_KERNEL
Ankita Garg8bb31b92006-10-02 02:17:36 -0700751 depends on KPROBES
Chris Snookfddd9cf2008-02-23 15:23:26 -0800752 depends on BLOCK
Ankita Garg8bb31b92006-10-02 02:17:36 -0700753 default n
754 help
755 This module enables testing of the different dumping mechanisms by
756 inducing system failures at predefined crash points.
757 If you don't need it: say N
758 Choose M here to compile this code as a module. The module will be
759 called lkdtm.
760
761 Documentation on how to use the module can be found in
762 drivers/misc/lkdtm.c
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800763
764config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800765 bool "Fault-injection framework"
766 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -0800767 help
768 Provide fault-injection framework.
769 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800770
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800771config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800772 bool "Fault-injection capability for kmalloc"
773 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +0900774 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800775 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800776 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800777
Akinobu Mita933e3122006-12-08 02:39:45 -0800778config FAIL_PAGE_ALLOC
779 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800780 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800781 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800782 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800783
Akinobu Mitac17bb492006-12-08 02:39:46 -0800784config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100785 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -0700786 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -0800787 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800788 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800789
Jens Axboe581d4e22008-09-14 05:56:33 -0700790config FAIL_IO_TIMEOUT
791 bool "Faul-injection capability for faking disk interrupts"
792 depends on FAULT_INJECTION && BLOCK
793 help
794 Provide fault-injection capability on end IO handling. This
795 will make the block layer "forget" an interrupt as configured,
796 thus exercising the error handling.
797
798 Only works with drivers that use the generic timeout handling,
799 for others it wont do anything.
800
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800801config FAULT_INJECTION_DEBUG_FS
802 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800803 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800804 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800805 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -0800806
807config FAULT_INJECTION_STACKTRACE_FILTER
808 bool "stacktrace filter for fault-injection capabilities"
809 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -0700810 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -0800811 select STACKTRACE
Heiko Carstens75ee0342009-04-23 13:58:10 +0200812 select FRAME_POINTER if !PPC && !S390
Akinobu Mita1df49002007-02-20 13:57:56 -0800813 help
814 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700815
Arjan van de Ven97455122008-01-25 21:08:34 +0100816config LATENCYTOP
817 bool "Latency measuring infrastructure"
Heiko Carstens75ee0342009-04-23 13:58:10 +0200818 select FRAME_POINTER if !MIPS && !PPC && !S390
Arjan van de Ven97455122008-01-25 21:08:34 +0100819 select KALLSYMS
820 select KALLSYMS_ALL
821 select STACKTRACE
822 select SCHEDSTATS
823 select SCHED_DEBUG
Heiko Carstensaa7d9352008-02-01 17:45:14 +0100824 depends on HAVE_LATENCYTOP_SUPPORT
Arjan van de Ven97455122008-01-25 21:08:34 +0100825 help
826 Enable this option if you want to use the LatencyTOP tool
827 to find out which userspace is blocking on what kernel operations.
828
Andi Kleen9e94cd32008-08-16 07:53:05 +0200829config SYSCTL_SYSCALL_CHECK
830 bool "Sysctl checks"
831 depends on SYSCTL_SYSCALL
832 ---help---
833 sys_sysctl uses binary paths that have been found challenging
834 to properly maintain and use. This enables checks that help
835 you to keep things correct.
836
Akinobu Mita6a11f752009-03-31 15:23:17 -0700837source mm/Kconfig.debug
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +0200838source kernel/trace/Kconfig
839
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100840config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +0100841 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100842 depends on PCI && X86
843 help
844 If you want to debug problems which hang or crash the kernel early
845 on boot and the crashing machine has a FireWire port, you can use
846 this feature to remotely access the memory of the crashed machine
847 over FireWire. This employs remote DMA as part of the OHCI1394
848 specification which is now the standard for FireWire controllers.
849
850 With remote DMA, you can monitor the printk buffer remotely using
851 firescope and access all memory below 4GB using fireproxy from gdb.
852 Even controlling a kernel debugger is possible using remote DMA.
853
854 Usage:
855
856 If ohci1394_dma=early is used as boot parameter, it will initialize
857 all OHCI1394 controllers which are found in the PCI config space.
858
859 As all changes to the FireWire bus such as enabling and disabling
860 devices cause a bus reset and thereby disable remote DMA for all
861 devices, be sure to have the cable plugged and FireWire enabled on
862 the debugging host before booting the debug target for debugging.
863
864 This code (~1k) is freed after boot. By then, the firewire stack
865 in charge of the OHCI-1394 controllers should be used instead.
866
867 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +0100868
Stefan Richter080de8c2008-02-28 20:54:43 +0100869config FIREWIRE_OHCI_REMOTE_DMA
870 bool "Remote debugging over FireWire with firewire-ohci"
871 depends on FIREWIRE_OHCI
872 help
873 This option lets you use the FireWire bus for remote debugging
874 with help of the firewire-ohci driver. It enables unfiltered
875 remote DMA in firewire-ohci.
876 See Documentation/debugging-via-ohci1394.txt for more information.
877
878 If unsure, say N.
879
Randy Dunlap152de302009-02-20 15:38:47 -0800880config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -0700881 bool "Build targets in Documentation/ tree"
882 depends on HEADERS_CHECK
883 help
884 This option attempts to build objects from the source files in the
885 kernel Documentation/ tree.
886
887 Say N if you are unsure.
888
Jason Barone9d376f2009-02-05 11:51:38 -0500889config DYNAMIC_DEBUG
Jason Baron86151fd2009-02-05 11:53:15 -0500890 bool "Enable dynamic printk() support"
Jason Baron346e15b2008-08-12 16:46:19 -0400891 default n
892 depends on PRINTK
Jason Baron86151fd2009-02-05 11:53:15 -0500893 depends on DEBUG_FS
Jason Baron346e15b2008-08-12 16:46:19 -0400894 help
895
896 Compiles debug level messages into the kernel, which would not
897 otherwise be available at runtime. These messages can then be
Jason Baron86151fd2009-02-05 11:53:15 -0500898 enabled/disabled based on various levels of scope - per source file,
899 function, module, format string, and line number. This mechanism
900 implicitly enables all pr_debug() and dev_dbg() calls. The impact of
901 this compile option is a larger kernel text size of about 2%.
Jason Baron346e15b2008-08-12 16:46:19 -0400902
903 Usage:
904
Jason Baron86151fd2009-02-05 11:53:15 -0500905 Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file,
906 which is contained in the 'debugfs' filesystem. Thus, the debugfs
907 filesystem must first be mounted before making use of this feature.
908 We refer the control file as: <debugfs>/dynamic_debug/ddebug. This
909 file contains a list of the debug statements that can be enabled. The
910 format for each line of the file is:
Jason Baron346e15b2008-08-12 16:46:19 -0400911
Jason Baron86151fd2009-02-05 11:53:15 -0500912 filename:lineno [module]function flags format
Jason Baron346e15b2008-08-12 16:46:19 -0400913
Jason Baron86151fd2009-02-05 11:53:15 -0500914 filename : source file of the debug statement
915 lineno : line number of the debug statement
916 module : module that contains the debug statement
917 function : function that contains the debug statement
918 flags : 'p' means the line is turned 'on' for printing
919 format : the format used for the debug statement
Jason Baron346e15b2008-08-12 16:46:19 -0400920
921 From a live system:
922
Jason Baron86151fd2009-02-05 11:53:15 -0500923 nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
924 # filename:lineno [module]function flags format
925 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
926 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
927 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
Jason Baron346e15b2008-08-12 16:46:19 -0400928
Jason Baron86151fd2009-02-05 11:53:15 -0500929 Example usage:
Jason Baron346e15b2008-08-12 16:46:19 -0400930
Jason Baron86151fd2009-02-05 11:53:15 -0500931 // enable the message at line 1603 of file svcsock.c
932 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
933 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400934
Jason Baron86151fd2009-02-05 11:53:15 -0500935 // enable all the messages in file svcsock.c
936 nullarbor:~ # echo -n 'file svcsock.c +p' >
937 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400938
Jason Baron86151fd2009-02-05 11:53:15 -0500939 // enable all the messages in the NFS server module
940 nullarbor:~ # echo -n 'module nfsd +p' >
941 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400942
Jason Baron86151fd2009-02-05 11:53:15 -0500943 // enable all 12 messages in the function svc_process()
944 nullarbor:~ # echo -n 'func svc_process +p' >
945 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400946
Jason Baron86151fd2009-02-05 11:53:15 -0500947 // disable all 12 messages in the function svc_process()
948 nullarbor:~ # echo -n 'func svc_process -p' >
949 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400950
Jason Baron86151fd2009-02-05 11:53:15 -0500951 See Documentation/dynamic-debug-howto.txt for additional information.
Jason Baron346e15b2008-08-12 16:46:19 -0400952
Joerg Roedel5ee00bd2009-01-09 12:14:24 +0100953config DMA_API_DEBUG
954 bool "Enable debugging of DMA-API usage"
955 depends on HAVE_DMA_API_DEBUG
956 help
957 Enable this option to debug the use of the DMA API by device drivers.
958 With this option you will be able to detect common bugs in device
959 drivers like double-freeing of DMA mappings or freeing mappings that
960 were never allocated.
961 This option causes a performance degredation. Use only if you want
962 to debug device drivers. If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -0400963
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700964source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +0200965
966source "lib/Kconfig.kgdb"