blob: 891155817bc6e05aa52abc88e2fe7f93a9c41baa [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001
2config PRINTK_TIME
3 bool "Show timing information on printks"
Randy Dunlapd3b8b6e2006-12-06 20:36:38 -08004 depends on PRINTK
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 help
6 Selecting this option causes timing information to be
7 included in printk output. This allows you to measure
8 the interval between kernel operations, including bootup
9 operations. This is useful for identifying long delays
10 in kernel startup.
11
Jeff Garzikde488442007-10-25 04:06:13 -040012config ENABLE_WARN_DEPRECATED
13 bool "Enable __deprecated logic"
14 default y
15 help
16 Enable the __deprecated logic in the kernel build.
17 Disable this to suppress the "warning: 'foo' is deprecated
18 (declared at kernel/power/somefile.c:1234)" messages.
19
Andrew Mortoncebc04b2006-08-14 22:43:18 -070020config ENABLE_MUST_CHECK
21 bool "Enable __must_check logic"
22 default y
23 help
24 Enable the __must_check logic in the kernel build. Disable this to
25 suppress the "warning: ignoring return value of 'foo', declared with
26 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
Andi Kleen35bb5b12008-02-22 15:15:03 +010028config FRAME_WARN
29 int "Warn for stack frames larger than (needs gcc 4.4)"
30 range 0 8192
31 default 1024 if !64BIT
32 default 2048 if 64BIT
33 help
34 Tell gcc to warn at build time for stack frames larger than this.
35 Setting this too low will cause a lot of warnings.
36 Setting it to 0 disables the warning.
37 Requires gcc 4.4
38
Linus Torvalds1da177e2005-04-16 15:20:36 -070039config MAGIC_SYSRQ
40 bool "Magic SysRq key"
Adrian Bunkf346f4b2006-01-09 20:54:51 -080041 depends on !UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 help
43 If you say Y here, you will have some control over the system even
44 if the system crashes for example during kernel debugging (e.g., you
45 will be able to flush the buffer cache to disk, reboot the system
46 immediately or dump some status information). This is accomplished
47 by pressing various keys while holding SysRq (Alt+PrintScreen). It
48 also works on a serial console (on PC hardware at least), if you
49 send a BREAK and then within 5 seconds a command keypress. The
50 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
51 unless you really know what this hack does.
52
Randy Dunlap99657c72009-09-18 12:49:22 -070053config STRIP_ASM_SYMS
54 bool "Strip assembler-generated symbols during link"
55 default n
56 help
57 Strip internal assembler-generated symbols during a link (symbols
58 that look like '.Lxxx') so they don't pollute the output of
59 get_wchan() and suchlike.
60
Arjan van de Venf71d20e2006-06-28 04:26:45 -070061config UNUSED_SYMBOLS
62 bool "Enable unused/obsolete exported symbols"
63 default y if X86
64 help
65 Unused but exported symbols make the kernel needlessly bigger. For
66 that reason most of these unused exports will soon be removed. This
67 option is provided temporarily to provide a transition period in case
68 some external kernel module needs one of these symbols anyway. If you
69 encounter such a case in your module, consider if you are actually
70 using the right API. (rationale: since nobody in the kernel is using
71 this in a module, there is a pretty good chance it's actually the
72 wrong interface to use). If you really need the symbol, please send a
73 mail to the linux kernel mailing list mentioning the symbol and why
74 you really need it, and what the merge plan to the mainline kernel for
75 your module is.
76
Don Mullisbf4735a2006-12-10 02:18:37 -080077config DEBUG_FS
78 bool "Debug Filesystem"
79 depends on SYSFS
80 help
81 debugfs is a virtual file system that kernel developers use to put
82 debugging files into. Enable this option to be able to read and
83 write to these files.
84
Robert P. J. Dayff543332008-05-20 00:06:00 +020085 For detailed documentation on the debugfs API, see
86 Documentation/DocBook/filesystems.
87
Don Mullisbf4735a2006-12-10 02:18:37 -080088 If unsure, say N.
89
90config HEADERS_CHECK
91 bool "Run 'make headers_check' when building vmlinux"
92 depends on !UML
93 help
94 This option will extract the user-visible kernel headers whenever
95 building the kernel, and will run basic sanity checks on them to
96 ensure that exported files do not attempt to include files which
97 were not exported, etc.
98
99 If you're making modifications to header files which are
100 relevant for userspace, say 'Y', and check the headers
101 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
102 your build tree), to make sure they're suitable.
103
Sam Ravnborg91341d42008-01-21 21:31:44 +0100104config DEBUG_SECTION_MISMATCH
105 bool "Enable full Section mismatch analysis"
Sam Ravnborge5f95c82008-02-02 18:57:18 +0100106 depends on UNDEFINED
Sam Ravnborgfa2144b2008-02-15 13:53:11 +0100107 # This option is on purpose disabled for now.
108 # It will be enabled when we are down to a resonable number
109 # of section mismatch warnings (< 10 for an allyesconfig build)
Sam Ravnborg91341d42008-01-21 21:31:44 +0100110 help
111 The section mismatch analysis checks if there are illegal
112 references from one section to another section.
113 Linux will during link or during runtime drop some sections
114 and any use of code/data previously in these sections will
115 most likely result in an oops.
116 In the code functions and variables are annotated with
117 __init, __devinit etc. (see full list in include/linux/init.h)
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100118 which results in the code/data being placed in specific sections.
119 The section mismatch analysis is always done after a full
120 kernel build but enabling this option will in addition
Sam Ravnborg91341d42008-01-21 21:31:44 +0100121 do the following:
122 - Add the option -fno-inline-functions-called-once to gcc
123 When inlining a function annotated __init in a non-init
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100124 function we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100125 the analysis would not catch the illegal reference.
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100126 This option tells gcc to inline less but will also
Sam Ravnborg91341d42008-01-21 21:31:44 +0100127 result in a larger kernel.
128 - Run the section mismatch analysis for each module/built-in.o
129 When we run the section mismatch analysis on vmlinux.o we
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100130 lose valueble information about where the mismatch was
Sam Ravnborg91341d42008-01-21 21:31:44 +0100131 introduced.
132 Running the analysis for each module/built-in.o file
133 will tell where the mismatch happens much closer to the
134 source. The drawback is that we will report the same
135 mismatch at least twice.
Sam Ravnborg588ccd72008-01-24 21:12:37 +0100136 - Enable verbose reporting from modpost to help solving
137 the section mismatches reported.
Sam Ravnborg91341d42008-01-21 21:31:44 +0100138
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800139config DEBUG_KERNEL
140 bool "Kernel debugging"
141 help
142 Say Y here if you are developing drivers or trying to debug and
143 identify kernel problems.
144
David Woodhousea304e1b2007-02-12 00:52:00 -0800145config DEBUG_SHIRQ
146 bool "Debug shared IRQ handlers"
147 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
148 help
149 Enable this to generate a spurious interrupt as soon as a shared
150 interrupt handler is registered, and just before one is deregistered.
151 Drivers ought to be able to handle interrupts coming in at those
152 points; some don't and need to be caught.
153
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700154config DETECT_SOFTLOCKUP
155 bool "Detect Soft Lockups"
Heiko Carstensdea20a32006-10-11 01:20:44 -0700156 depends on DEBUG_KERNEL && !S390
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700157 default y
158 help
159 Say Y here to enable the kernel to detect "soft lockups",
160 which are bugs that cause the kernel to loop in kernel
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200161 mode for more than 60 seconds, without giving other tasks a
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700162 chance to run.
163
164 When a soft-lockup is detected, the kernel will print the
165 current stack trace (which you should report), but the
166 system will stay locked up. This feature has negligible
167 overhead.
168
169 (Note that "hard lockups" are separate type of bugs that
170 can be detected via the NMI-watchdog, on platforms that
171 support it.)
172
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200173config BOOTPARAM_SOFTLOCKUP_PANIC
174 bool "Panic (Reboot) On Soft Lockups"
175 depends on DETECT_SOFTLOCKUP
176 help
177 Say Y here to enable the kernel to panic on "soft lockups",
178 which are bugs that cause the kernel to loop in kernel
179 mode for more than 60 seconds, without giving other tasks a
180 chance to run.
181
182 The panic can be used in combination with panic_timeout,
183 to cause the system to reboot automatically after a
184 lockup has been detected. This feature is useful for
185 high-availability systems that have uptime guarantees and
186 where a lockup must be resolved ASAP.
187
188 Say N if unsure.
189
190config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
191 int
192 depends on DETECT_SOFTLOCKUP
193 range 0 1
194 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
195 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
196
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800197config DETECT_HUNG_TASK
198 bool "Detect Hung Tasks"
199 depends on DEBUG_KERNEL
Ingo Molnar77d05632009-04-07 08:55:36 +0200200 default DETECT_SOFTLOCKUP
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800201 help
202 Say Y here to enable the kernel to detect "hung tasks",
203 which are bugs that cause the task to be stuck in
204 uninterruptible "D" state indefinitiley.
205
206 When a hung task is detected, the kernel will print the
207 current stack trace (which you should report), but the
208 task will stay in uninterruptible state. If lockdep is
209 enabled then all held locks will also be reported. This
210 feature has negligible overhead.
211
212config BOOTPARAM_HUNG_TASK_PANIC
213 bool "Panic (Reboot) On Hung Tasks"
214 depends on DETECT_HUNG_TASK
215 help
216 Say Y here to enable the kernel to panic on "hung tasks",
217 which are bugs that cause the kernel to leave a task stuck
218 in uninterruptible "D" state.
219
220 The panic can be used in combination with panic_timeout,
221 to cause the system to reboot automatically after a
222 hung task has been detected. This feature is useful for
223 high-availability systems that have uptime guarantees and
224 where a hung tasks must be resolved ASAP.
225
226 Say N if unsure.
227
228config BOOTPARAM_HUNG_TASK_PANIC_VALUE
229 int
230 depends on DETECT_HUNG_TASK
231 range 0 1
232 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
233 default 1 if BOOTPARAM_HUNG_TASK_PANIC
234
Ingo Molnarb642b6d2007-07-09 18:52:00 +0200235config SCHED_DEBUG
236 bool "Collect scheduler debugging info"
237 depends on DEBUG_KERNEL && PROC_FS
238 default y
239 help
240 If you say Y here, the /proc/sched_debug file will be provided
241 that can help debug the scheduler. The runtime overhead of this
242 option is minimal.
243
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244config SCHEDSTATS
245 bool "Collect scheduler statistics"
246 depends on DEBUG_KERNEL && PROC_FS
247 help
248 If you say Y here, additional code will be inserted into the
249 scheduler and related routines to collect statistics about
250 scheduler behavior and provide them in /proc/schedstat. These
251 stats may be useful for both tuning and debugging the scheduler
252 If you aren't debugging the scheduler or trying to tune a specific
253 application, you can say N to avoid the very slight overhead
254 this adds.
255
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800256config TIMER_STATS
257 bool "Collect kernel timers statistics"
258 depends on DEBUG_KERNEL && PROC_FS
259 help
260 If you say Y here, additional code will be inserted into the
261 timer routines to collect statistics about kernel timers being
262 reprogrammed. The statistics can be read from /proc/timer_stats.
263 The statistics collection is started by writing 1 to /proc/timer_stats,
264 writing 0 stops it. This feature is useful to collect information
Ingo Molnarc1a834d2007-06-01 00:47:16 -0700265 about timer usage patterns in kernel and userspace. This feature
266 is lightweight if enabled in the kernel config but not activated
267 (it defaults to deactivated on bootup and will only be activated
268 if some application like powertop activates it explicitly).
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800269
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700270config DEBUG_OBJECTS
271 bool "Debug object operations"
272 depends on DEBUG_KERNEL
273 help
274 If you say Y here, additional code will be inserted into the
275 kernel to track the life time of various objects and validate
276 the operations on those objects.
277
278config DEBUG_OBJECTS_SELFTEST
279 bool "Debug objects selftest"
280 depends on DEBUG_OBJECTS
281 help
282 This enables the selftest of the object debug code.
283
284config DEBUG_OBJECTS_FREE
285 bool "Debug objects in freed memory"
286 depends on DEBUG_OBJECTS
287 help
288 This enables checks whether a k/v free operation frees an area
289 which contains an object which has not been deactivated
290 properly. This can make kmalloc/kfree-intensive workloads
291 much slower.
292
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700293config DEBUG_OBJECTS_TIMERS
294 bool "Debug timer objects"
295 depends on DEBUG_OBJECTS
296 help
297 If you say Y here, additional code will be inserted into the
298 timer routines to track the life time of timer objects and
299 validate the timer operations.
300
Ingo Molnar3ae70202008-11-26 10:02:00 +0100301config DEBUG_OBJECTS_ENABLE_DEFAULT
302 int "debug_objects bootup default value (0-1)"
303 range 0 1
304 default "1"
305 depends on DEBUG_OBJECTS
306 help
307 Debug objects boot parameter default value
308
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800310 bool "Debug slab memory allocations"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200311 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 help
313 Say Y here to have the kernel do limited verification on memory
314 allocation as well as poisoning memory on free to catch use of freed
315 memory. This can make kmalloc/kfree-intensive workloads much slower.
316
Al Viro871751e2006-03-25 03:06:39 -0800317config DEBUG_SLAB_LEAK
318 bool "Memory leak debugging"
319 depends on DEBUG_SLAB
320
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700321config SLUB_DEBUG_ON
322 bool "SLUB debugging on by default"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200323 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700324 default n
325 help
326 Boot with debugging on by default. SLUB boots by default with
327 the runtime debug capabilities switched off. Enabling this is
328 equivalent to specifying the "slub_debug" parameter on boot.
329 There is no support for more fine grained debug control like
330 possible with slub_debug=xxx. SLUB debugging may be switched
331 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
332 "slub_debug=-".
333
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800334config SLUB_STATS
335 default n
336 bool "Enable SLUB performance statistics"
Christoph Lameter5b06c8532008-04-14 18:51:34 +0300337 depends on SLUB && SLUB_DEBUG && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800338 help
339 SLUB statistics are useful to debug SLUBs allocation behavior in
340 order find ways to optimize the allocator. This should never be
341 enabled for production use since keeping statistics slows down
342 the allocator by a few percentage points. The slabinfo command
343 supports the determination of the most active slabs to figure
344 out which slabs are relevant to a particular load.
345 Try running: slabinfo -DA
346
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100347config DEBUG_KMEMLEAK
348 bool "Kernel memory leak detector"
Michael Ellermanbbdc16f2009-07-15 15:25:22 +0000349 depends on DEBUG_KERNEL && EXPERIMENTAL && (X86 || ARM || PPC) && \
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100350 !MEMORY_HOTPLUG
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100351 select DEBUG_FS if SYSFS
352 select STACKTRACE if STACKTRACE_SUPPORT
353 select KALLSYMS
354 help
355 Say Y here if you want to enable the memory leak
356 detector. The memory allocation/freeing is traced in a way
357 similar to the Boehm's conservative garbage collector, the
358 difference being that the orphan objects are not freed but
359 only shown in /sys/kernel/debug/kmemleak. Enabling this
360 feature will introduce an overhead to memory
361 allocations. See Documentation/kmemleak.txt for more
362 details.
363
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100364 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
365 of finding leaks due to the slab objects poisoning.
366
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100367 In order to access the kmemleak file, debugfs needs to be
368 mounted (usually at /sys/kernel/debug).
369
Catalin Marinasa9d90582009-06-25 10:16:11 +0100370config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
371 int "Maximum kmemleak early log entries"
372 depends on DEBUG_KMEMLEAK
373 range 200 2000
374 default 400
375 help
376 Kmemleak must track all the memory allocations to avoid
377 reporting false positives. Since memory may be allocated or
378 freed before kmemleak is initialised, an early log buffer is
379 used to store these actions. If kmemleak reports "early log
380 buffer exceeded", please increase this value.
381
Catalin Marinas0822ee42009-06-11 13:24:14 +0100382config DEBUG_KMEMLEAK_TEST
383 tristate "Simple test for the kernel memory leak detector"
384 depends on DEBUG_KMEMLEAK
385 help
386 Say Y or M here to build a test for the kernel memory leak
387 detector. This option enables a module that explicitly leaks
388 memory.
389
390 If unsure, say N.
391
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392config DEBUG_PREEMPT
393 bool "Debug preemptible kernel"
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100394 depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 default y
396 help
397 If you say Y here then the kernel will use a debug variant of the
398 commonly used smp_processor_id() function and will print warnings
399 if kernel code uses it in a preemption-unsafe way. Also, the kernel
400 will detect preemption count underflows.
401
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700402config DEBUG_RT_MUTEXES
403 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700404 depends on DEBUG_KERNEL && RT_MUTEXES
405 help
406 This allows rt mutex semantics violations and rt mutex related
407 deadlocks (lockups) to be detected and reported automatically.
408
409config DEBUG_PI_LIST
410 bool
411 default y
412 depends on DEBUG_RT_MUTEXES
413
Thomas Gleixner61a87122006-06-27 02:54:56 -0700414config RT_MUTEX_TESTER
415 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700416 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700417 help
418 This option enables a rt-mutex tester.
419
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700421 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 depends on DEBUG_KERNEL
423 help
424 Say Y here and build SMP to catch missing spinlock initialization
425 and certain other kinds of spinlock errors commonly made. This is
426 best used in conjunction with the NMI watchdog so that spinlock
427 deadlocks are also debuggable.
428
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700429config DEBUG_MUTEXES
430 bool "Mutex debugging: basic checks"
431 depends on DEBUG_KERNEL
432 help
433 This feature allows mutex semantics violations to be detected and
434 reported.
435
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700436config DEBUG_LOCK_ALLOC
437 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700438 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700439 select DEBUG_SPINLOCK
440 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700441 select LOCKDEP
442 help
443 This feature will check whether any held lock (spinlock, rwlock,
444 mutex or rwsem) is incorrectly freed by the kernel, via any of the
445 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
446 vfree(), etc.), whether a live lock is incorrectly reinitialized via
447 spin_lock_init()/mutex_init()/etc., or whether there is any lock
448 held during task exit.
449
450config PROVE_LOCKING
451 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700452 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700453 select LOCKDEP
454 select DEBUG_SPINLOCK
455 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700456 select DEBUG_LOCK_ALLOC
457 default n
458 help
459 This feature enables the kernel to prove that all locking
460 that occurs in the kernel runtime is mathematically
461 correct: that under no circumstance could an arbitrary (and
462 not yet triggered) combination of observed locking
463 sequences (on an arbitrary number of CPUs, running an
464 arbitrary number of tasks and interrupt contexts) cause a
465 deadlock.
466
467 In short, this feature enables the kernel to report locking
468 related deadlocks before they actually occur.
469
470 The proof does not depend on how hard and complex a
471 deadlock scenario would be to trigger: how many
472 participant CPUs, tasks and irq-contexts would be needed
473 for it to trigger. The proof also does not depend on
474 timing: if a race and a resulting deadlock is possible
475 theoretically (no matter how unlikely the race scenario
476 is), it will be proven so and will immediately be
477 reported by the kernel (once the event is observed that
478 makes the deadlock theoretically possible).
479
480 If a deadlock is impossible (i.e. the locking rules, as
481 observed by the kernel, are mathematically correct), the
482 kernel reports nothing.
483
484 NOTE: this feature can also be enabled for rwlocks, mutexes
485 and rwsems - in which case all dependencies between these
486 different locking variants are observed and mapped too, and
487 the proof of observed correctness is also maintained for an
488 arbitrary combination of these separate locking variants.
489
490 For more details, see Documentation/lockdep-design.txt.
491
492config LOCKDEP
493 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700494 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700495 select STACKTRACE
Peter Zijlstra00540e52009-06-12 10:04:01 +0200496 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700497 select KALLSYMS
498 select KALLSYMS_ALL
499
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700500config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700501 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700502 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
503 select LOCKDEP
504 select DEBUG_SPINLOCK
505 select DEBUG_MUTEXES
506 select DEBUG_LOCK_ALLOC
507 default n
508 help
509 This feature enables tracking lock contention points
510
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700511 For more details, see Documentation/lockstat.txt
512
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700513config DEBUG_LOCKDEP
514 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700515 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700516 help
517 If you say Y here, the lock dependency engine will do
518 additional runtime checks to debug itself, at the price
519 of more runtime overhead.
520
521config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700522 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700523 bool
524 default y
525 depends on TRACE_IRQFLAGS_SUPPORT
526 depends on PROVE_LOCKING
527
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700529 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 depends on DEBUG_KERNEL
531 help
532 If you say Y here, various routines which may sleep will become very
533 noisy if they are called with a spinlock held.
534
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700535config DEBUG_LOCKING_API_SELFTESTS
536 bool "Locking API boot-time self-tests"
537 depends on DEBUG_KERNEL
538 help
539 Say Y here if you want the kernel to run a short self-test during
540 bootup. The self-test checks whether common types of locking bugs
541 are detected by debugging mechanisms or not. (if you disable
542 lock debugging then those bugs wont be detected of course.)
543 The following locking APIs are covered: spinlocks, rwlocks,
544 mutexes and rwsems.
545
Ingo Molnar8637c092006-07-03 00:24:38 -0700546config STACKTRACE
547 bool
548 depends on STACKTRACE_SUPPORT
549
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550config DEBUG_KOBJECT
551 bool "kobject debugging"
552 depends on DEBUG_KERNEL
553 help
554 If you say Y here, some extra kobject debugging messages will be sent
555 to the syslog.
556
557config DEBUG_HIGHMEM
558 bool "Highmem debugging"
559 depends on DEBUG_KERNEL && HIGHMEM
560 help
561 This options enables addition error checking for high memory systems.
562 Disable for production systems.
563
564config DEBUG_BUGVERBOSE
565 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700566 depends on BUG
David Howellsb920de12008-02-08 04:19:31 -0800567 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
568 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 default !EMBEDDED
570 help
571 Say Y here to make BUG() panics output the file name and line number
572 of the BUG call as well as the EIP and oops trace. This aids
573 debugging but costs about 70-100K of memory.
574
575config DEBUG_INFO
576 bool "Compile the kernel with debug info"
577 depends on DEBUG_KERNEL
578 help
579 If you say Y here the resulting kernel image will include
580 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600581 This adds debug symbols to the kernel and modules (gcc -g), and
582 is needed if you intend to use kernel crashdump or binary object
583 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 Say Y here only if you plan to debug the kernel.
585
586 If unsure, say N.
587
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800588config DEBUG_VM
589 bool "Debug VM"
590 depends on DEBUG_KERNEL
591 help
Nick Piggin13e74442006-01-06 00:10:58 -0800592 Enable this to turn on extended checks in the virtual-memory system
593 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800594
595 If unsure, say N.
596
Jiri Slaby59ea7462008-06-12 13:56:40 +0200597config DEBUG_VIRTUAL
598 bool "Debug VM translations"
599 depends on DEBUG_KERNEL && X86
600 help
601 Enable some costly sanity checks in virtual to page code. This can
602 catch mistakes with virt_to_page() and friends.
603
604 If unsure, say N.
605
David Howells8feae132009-01-08 12:04:47 +0000606config DEBUG_NOMMU_REGIONS
607 bool "Debug the global anon/private NOMMU mapping region tree"
608 depends on DEBUG_KERNEL && !MMU
609 help
610 This option causes the global tree of anonymous and private mapping
611 regions to be regularly checked for invalid topology.
612
Dave Hansenad775f52008-02-15 14:38:01 -0800613config DEBUG_WRITECOUNT
614 bool "Debug filesystem writers count"
615 depends on DEBUG_KERNEL
616 help
617 Enable this to catch wrong use of the writers count in struct
618 vfsmount. This will increase the size of each file struct by
619 32 bits.
620
621 If unsure, say N.
622
Mel Gorman6b74ab92008-07-23 21:26:49 -0700623config DEBUG_MEMORY_INIT
624 bool "Debug memory initialisation" if EMBEDDED
625 default !EMBEDDED
626 help
627 Enable this for additional checks during memory initialisation.
628 The sanity checks verify aspects of the VM such as the memory model
629 and other information provided by the architecture. Verbose
630 information will be printed at KERN_DEBUG loglevel depending
631 on the mminit_loglevel= command-line option.
632
633 If unsure, say Y
634
Dave Jones199a9af2006-09-29 01:59:00 -0700635config DEBUG_LIST
636 bool "Debug linked list manipulation"
637 depends on DEBUG_KERNEL
638 help
639 Enable this to turn on extended checks in the linked-list
640 walking routines.
641
642 If unsure, say N.
643
Jens Axboed6ec0842007-10-22 20:01:06 +0200644config DEBUG_SG
645 bool "Debug SG table operations"
646 depends on DEBUG_KERNEL
647 help
648 Enable this to turn on checks on scatter-gather tables. This can
649 help find problems with drivers that do not properly initialize
650 their sg tables.
651
652 If unsure, say N.
653
Arjan van de Ven1b2439d2008-08-15 15:29:38 -0700654config DEBUG_NOTIFIERS
655 bool "Debug notifier call chains"
656 depends on DEBUG_KERNEL
657 help
658 Enable this to turn on sanity checking for notifier call chains.
659 This is most useful for kernel developers to make sure that
660 modules properly unregister themselves from notifier chains.
661 This is a relatively cheap check but if you care about maximum
662 performance, say N.
663
David Howellse0e81732009-09-02 09:13:40 +0100664config DEBUG_CREDENTIALS
665 bool "Debug credential management"
666 depends on DEBUG_KERNEL
667 help
668 Enable this to turn on some debug checking for credential
669 management. The additional code keeps track of the number of
670 pointers from task_structs to any given cred struct, and checks to
671 see that this number never exceeds the usage count of the cred
672 struct.
673
674 Furthermore, if SELinux is enabled, this also checks that the
675 security pointer in the cred struct is never seen to be invalid.
676
677 If unsure, say N.
678
Jeff Mahoney64dec402009-01-16 13:23:35 -0500679#
680# Select this config option from the architecture Kconfig, if it
681# it is preferred to always offer frame pointers as a config
682# option on the architecture (regardless of KERNEL_DEBUG):
683#
684config ARCH_WANT_FRAME_POINTERS
685 bool
686 help
687
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688config FRAME_POINTER
689 bool "Compile the kernel with frame pointers"
David Howellsb920de12008-02-08 04:19:31 -0800690 depends on DEBUG_KERNEL && \
Heiko Carstens75ee0342009-04-23 13:58:10 +0200691 (CRIS || M68K || M68KNOMMU || FRV || UML || \
Ingo Molnarda4276b2009-01-07 11:05:10 +0100692 AVR32 || SUPERH || BLACKFIN || MN10300) || \
693 ARCH_WANT_FRAME_POINTERS
694 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695 help
Ingo Molnarda4276b2009-01-07 11:05:10 +0100696 If you say Y here the resulting kernel image will be slightly
697 larger and slower, but it gives very useful debugging information
698 in case of kernel bugs. (precise oopses/stacktraces/warnings)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700700config BOOT_PRINTK_DELAY
701 bool "Delay each boot printk message by N milliseconds"
702 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
703 help
704 This build option allows you to read kernel boot messages
705 by inserting a short delay after each one. The delay is
706 specified in milliseconds on the kernel command line,
707 using "boot_delay=N".
708
709 It is likely that you would also need to use "lpj=M" to preset
710 the "loops per jiffie" value.
711 See a previous boot log for the "lpj" value to use for your
712 system, and then set "lpj=M" before setting "boot_delay=N".
713 NOTE: Using this option may adversely affect SMP systems.
714 I.e., processors other than the first one may not boot up.
715 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
716 what it believes to be lockup conditions.
717
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800718config RCU_TORTURE_TEST
719 tristate "torture tests for RCU"
720 depends on DEBUG_KERNEL
721 default n
722 help
723 This option provides a kernel module that runs torture tests
724 on the RCU infrastructure. The kernel module may be built
725 after the fact on the running kernel to be tested, if desired.
726
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700727 Say Y here if you want RCU torture tests to be built into
728 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800729 Say M if you want the RCU torture tests to build as a module.
730 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700731
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700732config RCU_TORTURE_TEST_RUNNABLE
733 bool "torture tests for RCU runnable by default"
734 depends on RCU_TORTURE_TEST = y
735 default n
736 help
737 This option provides a way to build the RCU torture tests
738 directly into the kernel without them starting up at boot
739 time. You can use /proc/sys/kernel/rcutorture_runnable
740 to manually override this setting. This /proc file is
741 available only when the RCU torture tests have been built
742 into the kernel.
743
744 Say Y here if you want the RCU torture tests to start during
745 boot (you probably don't).
746 Say N here if you want the RCU torture tests to start only
747 after being manually enabled via /proc.
748
Paul E. McKenney2133b5d2008-10-02 16:06:39 -0700749config RCU_CPU_STALL_DETECTOR
Paul E. McKenney67182ae2008-08-10 18:35:38 -0700750 bool "Check for stalled CPUs delaying RCU grace periods"
Paul E. McKenney6b3ef482009-08-22 13:56:53 -0700751 depends on TREE_RCU || TREE_PREEMPT_RCU
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100752 default n
753 help
754 This option causes RCU to printk information on which
755 CPUs are delaying the current grace period, but only when
756 the grace period extends for excessive time periods.
757
758 Say Y if you want RCU to perform such checks.
759
760 Say N if you are unsure.
761
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +0100762config KPROBES_SANITY_TEST
763 bool "Kprobes sanity tests"
764 depends on DEBUG_KERNEL
765 depends on KPROBES
766 default n
767 help
768 This option provides for testing basic kprobes functionality on
769 boot. A sample kprobe, jprobe and kretprobe are inserted and
770 verified for functionality.
771
772 Say N if you are unsure.
773
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100774config BACKTRACE_SELF_TEST
775 tristate "Self test for the backtrace code"
776 depends on DEBUG_KERNEL
777 default n
778 help
779 This option provides a kernel module that can be used to test
780 the kernel stack backtrace code. This option is not useful
781 for distributions or general kernels, but only for kernel
782 developers working on architecture code.
783
Vegard Nossumad118c52008-06-27 18:04:48 +0200784 Note that if you want to also test saved backtraces, you will
785 have to enable STACKTRACE as well.
786
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100787 Say N if you are unsure.
788
Tejun Heo870d6652008-08-25 19:47:25 +0900789config DEBUG_BLOCK_EXT_DEVT
790 bool "Force extended block device numbers and spread them"
791 depends on DEBUG_KERNEL
792 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +0200793 default n
Tejun Heo870d6652008-08-25 19:47:25 +0900794 help
Tejun Heo0e11e342008-10-13 10:46:01 +0200795 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
796 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
797 YOU ARE DOING. Distros, please enable this and fix whatever
798 is broken.
799
Tejun Heo870d6652008-08-25 19:47:25 +0900800 Conventionally, block device numbers are allocated from
801 predetermined contiguous area. However, extended block area
802 may introduce non-contiguous block device numbers. This
803 option forces most block device numbers to be allocated from
804 the extended space and spreads them to discover kernel or
805 userland code paths which assume predetermined contiguous
806 device number allocation.
807
Tejun Heo55dc7db2008-09-01 13:44:35 +0200808 Note that turning on this debug option shuffles all the
809 device numbers for all IDE and SCSI devices including libata
810 ones, so root partition specified using device number
811 directly (via rdev or root=MAJ:MIN) won't work anymore.
812 Textual device names (root=/dev/sdXn) will continue to work.
813
Tejun Heo870d6652008-08-25 19:47:25 +0900814 Say N if you are unsure.
815
Tejun Heo7c756e62009-06-24 15:13:50 +0900816config DEBUG_FORCE_WEAK_PER_CPU
817 bool "Force weak per-cpu definitions"
818 depends on DEBUG_KERNEL
819 help
820 s390 and alpha require percpu variables in modules to be
821 defined weak to work around addressing range issue which
822 puts the following two restrictions on percpu variable
823 definitions.
824
825 1. percpu symbols must be unique whether static or not
826 2. percpu variables can't be defined inside a function
827
828 To ensure that generic code follows the above rules, this
829 option forces all percpu variables to be defined as weak.
830
Ankita Garg8bb31b92006-10-02 02:17:36 -0700831config LKDTM
832 tristate "Linux Kernel Dump Test Tool Module"
Don Mullisbf4735a2006-12-10 02:18:37 -0800833 depends on DEBUG_KERNEL
Ankita Garg8bb31b92006-10-02 02:17:36 -0700834 depends on KPROBES
Chris Snookfddd9cf2008-02-23 15:23:26 -0800835 depends on BLOCK
Ankita Garg8bb31b92006-10-02 02:17:36 -0700836 default n
837 help
838 This module enables testing of the different dumping mechanisms by
839 inducing system failures at predefined crash points.
840 If you don't need it: say N
841 Choose M here to compile this code as a module. The module will be
842 called lkdtm.
843
844 Documentation on how to use the module can be found in
845 drivers/misc/lkdtm.c
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800846
847config FAULT_INJECTION
Andrew Morton1ab85092006-12-08 02:39:49 -0800848 bool "Fault-injection framework"
849 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -0800850 help
851 Provide fault-injection framework.
852 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800853
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800854config FAILSLAB
Andrew Morton1ab85092006-12-08 02:39:49 -0800855 bool "Fault-injection capability for kmalloc"
856 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +0900857 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800858 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800859 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800860
Akinobu Mita933e3122006-12-08 02:39:45 -0800861config FAIL_PAGE_ALLOC
862 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab85092006-12-08 02:39:49 -0800863 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800864 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800865 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800866
Akinobu Mitac17bb492006-12-08 02:39:46 -0800867config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100868 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -0700869 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -0800870 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800871 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800872
Jens Axboe581d4e22008-09-14 05:56:33 -0700873config FAIL_IO_TIMEOUT
874 bool "Faul-injection capability for faking disk interrupts"
875 depends on FAULT_INJECTION && BLOCK
876 help
877 Provide fault-injection capability on end IO handling. This
878 will make the block layer "forget" an interrupt as configured,
879 thus exercising the error handling.
880
881 Only works with drivers that use the generic timeout handling,
882 for others it wont do anything.
883
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800884config FAULT_INJECTION_DEBUG_FS
885 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab85092006-12-08 02:39:49 -0800886 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800887 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800888 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -0800889
890config FAULT_INJECTION_STACKTRACE_FILTER
891 bool "stacktrace filter for fault-injection capabilities"
892 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -0700893 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -0800894 select STACKTRACE
Heiko Carstens75ee0342009-04-23 13:58:10 +0200895 select FRAME_POINTER if !PPC && !S390
Akinobu Mita1df49002007-02-20 13:57:56 -0800896 help
897 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700898
Arjan van de Ven97455122008-01-25 21:08:34 +0100899config LATENCYTOP
900 bool "Latency measuring infrastructure"
Heiko Carstens75ee0342009-04-23 13:58:10 +0200901 select FRAME_POINTER if !MIPS && !PPC && !S390
Arjan van de Ven97455122008-01-25 21:08:34 +0100902 select KALLSYMS
903 select KALLSYMS_ALL
904 select STACKTRACE
905 select SCHEDSTATS
906 select SCHED_DEBUG
Heiko Carstensaa7d9352008-02-01 17:45:14 +0100907 depends on HAVE_LATENCYTOP_SUPPORT
Arjan van de Ven97455122008-01-25 21:08:34 +0100908 help
909 Enable this option if you want to use the LatencyTOP tool
910 to find out which userspace is blocking on what kernel operations.
911
Andi Kleen9e94cd32008-08-16 07:53:05 +0200912config SYSCTL_SYSCALL_CHECK
913 bool "Sysctl checks"
914 depends on SYSCTL_SYSCALL
915 ---help---
916 sys_sysctl uses binary paths that have been found challenging
917 to properly maintain and use. This enables checks that help
918 you to keep things correct.
919
Akinobu Mita6a11f752009-03-31 15:23:17 -0700920source mm/Kconfig.debug
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +0200921source kernel/trace/Kconfig
922
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100923config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +0100924 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100925 depends on PCI && X86
926 help
927 If you want to debug problems which hang or crash the kernel early
928 on boot and the crashing machine has a FireWire port, you can use
929 this feature to remotely access the memory of the crashed machine
930 over FireWire. This employs remote DMA as part of the OHCI1394
931 specification which is now the standard for FireWire controllers.
932
933 With remote DMA, you can monitor the printk buffer remotely using
934 firescope and access all memory below 4GB using fireproxy from gdb.
935 Even controlling a kernel debugger is possible using remote DMA.
936
937 Usage:
938
939 If ohci1394_dma=early is used as boot parameter, it will initialize
940 all OHCI1394 controllers which are found in the PCI config space.
941
942 As all changes to the FireWire bus such as enabling and disabling
943 devices cause a bus reset and thereby disable remote DMA for all
944 devices, be sure to have the cable plugged and FireWire enabled on
945 the debugging host before booting the debug target for debugging.
946
947 This code (~1k) is freed after boot. By then, the firewire stack
948 in charge of the OHCI-1394 controllers should be used instead.
949
950 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +0100951
Stefan Richter080de8c2008-02-28 20:54:43 +0100952config FIREWIRE_OHCI_REMOTE_DMA
953 bool "Remote debugging over FireWire with firewire-ohci"
954 depends on FIREWIRE_OHCI
955 help
956 This option lets you use the FireWire bus for remote debugging
957 with help of the firewire-ohci driver. It enables unfiltered
958 remote DMA in firewire-ohci.
959 See Documentation/debugging-via-ohci1394.txt for more information.
960
961 If unsure, say N.
962
Randy Dunlap152de302009-02-20 15:38:47 -0800963config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -0700964 bool "Build targets in Documentation/ tree"
965 depends on HEADERS_CHECK
966 help
967 This option attempts to build objects from the source files in the
968 kernel Documentation/ tree.
969
970 Say N if you are unsure.
971
Jason Barone9d376f2009-02-05 11:51:38 -0500972config DYNAMIC_DEBUG
Jason Baron86151fd2009-02-05 11:53:15 -0500973 bool "Enable dynamic printk() support"
Jason Baron346e15b2008-08-12 16:46:19 -0400974 default n
975 depends on PRINTK
Jason Baron86151fd2009-02-05 11:53:15 -0500976 depends on DEBUG_FS
Jason Baron346e15b2008-08-12 16:46:19 -0400977 help
978
979 Compiles debug level messages into the kernel, which would not
980 otherwise be available at runtime. These messages can then be
Jason Baron86151fd2009-02-05 11:53:15 -0500981 enabled/disabled based on various levels of scope - per source file,
982 function, module, format string, and line number. This mechanism
983 implicitly enables all pr_debug() and dev_dbg() calls. The impact of
984 this compile option is a larger kernel text size of about 2%.
Jason Baron346e15b2008-08-12 16:46:19 -0400985
986 Usage:
987
Jason Baron86151fd2009-02-05 11:53:15 -0500988 Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file,
989 which is contained in the 'debugfs' filesystem. Thus, the debugfs
990 filesystem must first be mounted before making use of this feature.
991 We refer the control file as: <debugfs>/dynamic_debug/ddebug. This
992 file contains a list of the debug statements that can be enabled. The
993 format for each line of the file is:
Jason Baron346e15b2008-08-12 16:46:19 -0400994
Jason Baron86151fd2009-02-05 11:53:15 -0500995 filename:lineno [module]function flags format
Jason Baron346e15b2008-08-12 16:46:19 -0400996
Jason Baron86151fd2009-02-05 11:53:15 -0500997 filename : source file of the debug statement
998 lineno : line number of the debug statement
999 module : module that contains the debug statement
1000 function : function that contains the debug statement
1001 flags : 'p' means the line is turned 'on' for printing
1002 format : the format used for the debug statement
Jason Baron346e15b2008-08-12 16:46:19 -04001003
1004 From a live system:
1005
Jason Baron86151fd2009-02-05 11:53:15 -05001006 nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
1007 # filename:lineno [module]function flags format
1008 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
1009 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
1010 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
Jason Baron346e15b2008-08-12 16:46:19 -04001011
Jason Baron86151fd2009-02-05 11:53:15 -05001012 Example usage:
Jason Baron346e15b2008-08-12 16:46:19 -04001013
Jason Baron86151fd2009-02-05 11:53:15 -05001014 // enable the message at line 1603 of file svcsock.c
1015 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
1016 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001017
Jason Baron86151fd2009-02-05 11:53:15 -05001018 // enable all the messages in file svcsock.c
1019 nullarbor:~ # echo -n 'file svcsock.c +p' >
1020 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001021
Jason Baron86151fd2009-02-05 11:53:15 -05001022 // enable all the messages in the NFS server module
1023 nullarbor:~ # echo -n 'module nfsd +p' >
1024 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001025
Jason Baron86151fd2009-02-05 11:53:15 -05001026 // enable all 12 messages in the function svc_process()
1027 nullarbor:~ # echo -n 'func svc_process +p' >
1028 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001029
Jason Baron86151fd2009-02-05 11:53:15 -05001030 // disable all 12 messages in the function svc_process()
1031 nullarbor:~ # echo -n 'func svc_process -p' >
1032 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001033
Jason Baron86151fd2009-02-05 11:53:15 -05001034 See Documentation/dynamic-debug-howto.txt for additional information.
Jason Baron346e15b2008-08-12 16:46:19 -04001035
Joerg Roedel5ee00bd2009-01-09 12:14:24 +01001036config DMA_API_DEBUG
1037 bool "Enable debugging of DMA-API usage"
1038 depends on HAVE_DMA_API_DEBUG
1039 help
1040 Enable this option to debug the use of the DMA API by device drivers.
1041 With this option you will be able to detect common bugs in device
1042 drivers like double-freeing of DMA mappings or freeing mappings that
1043 were never allocated.
1044 This option causes a performance degredation. Use only if you want
1045 to debug device drivers. If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -04001046
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001047source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02001048
1049source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001050
1051source "lib/Kconfig.kmemcheck"