blob: 732b9f6ab1ee8bcf0d7deca60a3e0e2377c2a2c3 [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"
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200349 depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
350 (X86 || ARM || PPC || S390)
351
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100352 select DEBUG_FS if SYSFS
353 select STACKTRACE if STACKTRACE_SUPPORT
354 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800355 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100356 help
357 Say Y here if you want to enable the memory leak
358 detector. The memory allocation/freeing is traced in a way
359 similar to the Boehm's conservative garbage collector, the
360 difference being that the orphan objects are not freed but
361 only shown in /sys/kernel/debug/kmemleak. Enabling this
362 feature will introduce an overhead to memory
363 allocations. See Documentation/kmemleak.txt for more
364 details.
365
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100366 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
367 of finding leaks due to the slab objects poisoning.
368
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100369 In order to access the kmemleak file, debugfs needs to be
370 mounted (usually at /sys/kernel/debug).
371
Catalin Marinasa9d90582009-06-25 10:16:11 +0100372config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
373 int "Maximum kmemleak early log entries"
374 depends on DEBUG_KMEMLEAK
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200375 range 200 40000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100376 default 400
377 help
378 Kmemleak must track all the memory allocations to avoid
379 reporting false positives. Since memory may be allocated or
380 freed before kmemleak is initialised, an early log buffer is
381 used to store these actions. If kmemleak reports "early log
382 buffer exceeded", please increase this value.
383
Catalin Marinas0822ee42009-06-11 13:24:14 +0100384config DEBUG_KMEMLEAK_TEST
385 tristate "Simple test for the kernel memory leak detector"
386 depends on DEBUG_KMEMLEAK
387 help
388 Say Y or M here to build a test for the kernel memory leak
389 detector. This option enables a module that explicitly leaks
390 memory.
391
392 If unsure, say N.
393
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394config DEBUG_PREEMPT
395 bool "Debug preemptible kernel"
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100396 depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397 default y
398 help
399 If you say Y here then the kernel will use a debug variant of the
400 commonly used smp_processor_id() function and will print warnings
401 if kernel code uses it in a preemption-unsafe way. Also, the kernel
402 will detect preemption count underflows.
403
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700404config DEBUG_RT_MUTEXES
405 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700406 depends on DEBUG_KERNEL && RT_MUTEXES
407 help
408 This allows rt mutex semantics violations and rt mutex related
409 deadlocks (lockups) to be detected and reported automatically.
410
411config DEBUG_PI_LIST
412 bool
413 default y
414 depends on DEBUG_RT_MUTEXES
415
Thomas Gleixner61a87122006-06-27 02:54:56 -0700416config RT_MUTEX_TESTER
417 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700418 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700419 help
420 This option enables a rt-mutex tester.
421
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700423 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 depends on DEBUG_KERNEL
425 help
426 Say Y here and build SMP to catch missing spinlock initialization
427 and certain other kinds of spinlock errors commonly made. This is
428 best used in conjunction with the NMI watchdog so that spinlock
429 deadlocks are also debuggable.
430
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700431config DEBUG_MUTEXES
432 bool "Mutex debugging: basic checks"
433 depends on DEBUG_KERNEL
434 help
435 This feature allows mutex semantics violations to be detected and
436 reported.
437
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700438config DEBUG_LOCK_ALLOC
439 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700440 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700441 select DEBUG_SPINLOCK
442 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700443 select LOCKDEP
444 help
445 This feature will check whether any held lock (spinlock, rwlock,
446 mutex or rwsem) is incorrectly freed by the kernel, via any of the
447 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
448 vfree(), etc.), whether a live lock is incorrectly reinitialized via
449 spin_lock_init()/mutex_init()/etc., or whether there is any lock
450 held during task exit.
451
452config PROVE_LOCKING
453 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700454 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700455 select LOCKDEP
456 select DEBUG_SPINLOCK
457 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700458 select DEBUG_LOCK_ALLOC
459 default n
460 help
461 This feature enables the kernel to prove that all locking
462 that occurs in the kernel runtime is mathematically
463 correct: that under no circumstance could an arbitrary (and
464 not yet triggered) combination of observed locking
465 sequences (on an arbitrary number of CPUs, running an
466 arbitrary number of tasks and interrupt contexts) cause a
467 deadlock.
468
469 In short, this feature enables the kernel to report locking
470 related deadlocks before they actually occur.
471
472 The proof does not depend on how hard and complex a
473 deadlock scenario would be to trigger: how many
474 participant CPUs, tasks and irq-contexts would be needed
475 for it to trigger. The proof also does not depend on
476 timing: if a race and a resulting deadlock is possible
477 theoretically (no matter how unlikely the race scenario
478 is), it will be proven so and will immediately be
479 reported by the kernel (once the event is observed that
480 makes the deadlock theoretically possible).
481
482 If a deadlock is impossible (i.e. the locking rules, as
483 observed by the kernel, are mathematically correct), the
484 kernel reports nothing.
485
486 NOTE: this feature can also be enabled for rwlocks, mutexes
487 and rwsems - in which case all dependencies between these
488 different locking variants are observed and mapped too, and
489 the proof of observed correctness is also maintained for an
490 arbitrary combination of these separate locking variants.
491
492 For more details, see Documentation/lockdep-design.txt.
493
494config LOCKDEP
495 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700496 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700497 select STACKTRACE
Peter Zijlstra00540e52009-06-12 10:04:01 +0200498 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700499 select KALLSYMS
500 select KALLSYMS_ALL
501
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700502config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700503 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700504 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
505 select LOCKDEP
506 select DEBUG_SPINLOCK
507 select DEBUG_MUTEXES
508 select DEBUG_LOCK_ALLOC
509 default n
510 help
511 This feature enables tracking lock contention points
512
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700513 For more details, see Documentation/lockstat.txt
514
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700515config DEBUG_LOCKDEP
516 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700517 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700518 help
519 If you say Y here, the lock dependency engine will do
520 additional runtime checks to debug itself, at the price
521 of more runtime overhead.
522
523config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700524 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700525 bool
526 default y
527 depends on TRACE_IRQFLAGS_SUPPORT
528 depends on PROVE_LOCKING
529
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700531 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 depends on DEBUG_KERNEL
533 help
534 If you say Y here, various routines which may sleep will become very
535 noisy if they are called with a spinlock held.
536
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700537config DEBUG_LOCKING_API_SELFTESTS
538 bool "Locking API boot-time self-tests"
539 depends on DEBUG_KERNEL
540 help
541 Say Y here if you want the kernel to run a short self-test during
542 bootup. The self-test checks whether common types of locking bugs
543 are detected by debugging mechanisms or not. (if you disable
544 lock debugging then those bugs wont be detected of course.)
545 The following locking APIs are covered: spinlocks, rwlocks,
546 mutexes and rwsems.
547
Ingo Molnar8637c092006-07-03 00:24:38 -0700548config STACKTRACE
549 bool
550 depends on STACKTRACE_SUPPORT
551
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552config DEBUG_KOBJECT
553 bool "kobject debugging"
554 depends on DEBUG_KERNEL
555 help
556 If you say Y here, some extra kobject debugging messages will be sent
557 to the syslog.
558
559config DEBUG_HIGHMEM
560 bool "Highmem debugging"
561 depends on DEBUG_KERNEL && HIGHMEM
562 help
563 This options enables addition error checking for high memory systems.
564 Disable for production systems.
565
566config DEBUG_BUGVERBOSE
567 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700568 depends on BUG
David Howellsb920de12008-02-08 04:19:31 -0800569 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
570 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 default !EMBEDDED
572 help
573 Say Y here to make BUG() panics output the file name and line number
574 of the BUG call as well as the EIP and oops trace. This aids
575 debugging but costs about 70-100K of memory.
576
577config DEBUG_INFO
578 bool "Compile the kernel with debug info"
579 depends on DEBUG_KERNEL
580 help
581 If you say Y here the resulting kernel image will include
582 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600583 This adds debug symbols to the kernel and modules (gcc -g), and
584 is needed if you intend to use kernel crashdump or binary object
585 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586 Say Y here only if you plan to debug the kernel.
587
588 If unsure, say N.
589
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800590config DEBUG_VM
591 bool "Debug VM"
592 depends on DEBUG_KERNEL
593 help
Nick Piggin13e74442006-01-06 00:10:58 -0800594 Enable this to turn on extended checks in the virtual-memory system
595 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800596
597 If unsure, say N.
598
Jiri Slaby59ea7462008-06-12 13:56:40 +0200599config DEBUG_VIRTUAL
600 bool "Debug VM translations"
601 depends on DEBUG_KERNEL && X86
602 help
603 Enable some costly sanity checks in virtual to page code. This can
604 catch mistakes with virt_to_page() and friends.
605
606 If unsure, say N.
607
David Howells8feae132009-01-08 12:04:47 +0000608config DEBUG_NOMMU_REGIONS
609 bool "Debug the global anon/private NOMMU mapping region tree"
610 depends on DEBUG_KERNEL && !MMU
611 help
612 This option causes the global tree of anonymous and private mapping
613 regions to be regularly checked for invalid topology.
614
Dave Hansenad775f52008-02-15 14:38:01 -0800615config DEBUG_WRITECOUNT
616 bool "Debug filesystem writers count"
617 depends on DEBUG_KERNEL
618 help
619 Enable this to catch wrong use of the writers count in struct
620 vfsmount. This will increase the size of each file struct by
621 32 bits.
622
623 If unsure, say N.
624
Mel Gorman6b74ab92008-07-23 21:26:49 -0700625config DEBUG_MEMORY_INIT
626 bool "Debug memory initialisation" if EMBEDDED
627 default !EMBEDDED
628 help
629 Enable this for additional checks during memory initialisation.
630 The sanity checks verify aspects of the VM such as the memory model
631 and other information provided by the architecture. Verbose
632 information will be printed at KERN_DEBUG loglevel depending
633 on the mminit_loglevel= command-line option.
634
635 If unsure, say Y
636
Dave Jones199a9af2006-09-29 01:59:00 -0700637config DEBUG_LIST
638 bool "Debug linked list manipulation"
639 depends on DEBUG_KERNEL
640 help
641 Enable this to turn on extended checks in the linked-list
642 walking routines.
643
644 If unsure, say N.
645
Jens Axboed6ec0842007-10-22 20:01:06 +0200646config DEBUG_SG
647 bool "Debug SG table operations"
648 depends on DEBUG_KERNEL
649 help
650 Enable this to turn on checks on scatter-gather tables. This can
651 help find problems with drivers that do not properly initialize
652 their sg tables.
653
654 If unsure, say N.
655
Arjan van de Ven1b2439d2008-08-15 15:29:38 -0700656config DEBUG_NOTIFIERS
657 bool "Debug notifier call chains"
658 depends on DEBUG_KERNEL
659 help
660 Enable this to turn on sanity checking for notifier call chains.
661 This is most useful for kernel developers to make sure that
662 modules properly unregister themselves from notifier chains.
663 This is a relatively cheap check but if you care about maximum
664 performance, say N.
665
David Howellse0e81732009-09-02 09:13:40 +0100666config DEBUG_CREDENTIALS
667 bool "Debug credential management"
668 depends on DEBUG_KERNEL
669 help
670 Enable this to turn on some debug checking for credential
671 management. The additional code keeps track of the number of
672 pointers from task_structs to any given cred struct, and checks to
673 see that this number never exceeds the usage count of the cred
674 struct.
675
676 Furthermore, if SELinux is enabled, this also checks that the
677 security pointer in the cred struct is never seen to be invalid.
678
679 If unsure, say N.
680
Jeff Mahoney64dec402009-01-16 13:23:35 -0500681#
682# Select this config option from the architecture Kconfig, if it
683# it is preferred to always offer frame pointers as a config
684# option on the architecture (regardless of KERNEL_DEBUG):
685#
686config ARCH_WANT_FRAME_POINTERS
687 bool
688 help
689
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690config FRAME_POINTER
691 bool "Compile the kernel with frame pointers"
David Howellsb920de12008-02-08 04:19:31 -0800692 depends on DEBUG_KERNEL && \
Heiko Carstens75ee0342009-04-23 13:58:10 +0200693 (CRIS || M68K || M68KNOMMU || FRV || UML || \
Ingo Molnarda4276b2009-01-07 11:05:10 +0100694 AVR32 || SUPERH || BLACKFIN || MN10300) || \
695 ARCH_WANT_FRAME_POINTERS
696 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 help
Ingo Molnarda4276b2009-01-07 11:05:10 +0100698 If you say Y here the resulting kernel image will be slightly
699 larger and slower, but it gives very useful debugging information
700 in case of kernel bugs. (precise oopses/stacktraces/warnings)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700702config BOOT_PRINTK_DELAY
703 bool "Delay each boot printk message by N milliseconds"
704 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
705 help
706 This build option allows you to read kernel boot messages
707 by inserting a short delay after each one. The delay is
708 specified in milliseconds on the kernel command line,
709 using "boot_delay=N".
710
711 It is likely that you would also need to use "lpj=M" to preset
712 the "loops per jiffie" value.
713 See a previous boot log for the "lpj" value to use for your
714 system, and then set "lpj=M" before setting "boot_delay=N".
715 NOTE: Using this option may adversely affect SMP systems.
716 I.e., processors other than the first one may not boot up.
717 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
718 what it believes to be lockup conditions.
719
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800720config RCU_TORTURE_TEST
721 tristate "torture tests for RCU"
722 depends on DEBUG_KERNEL
723 default n
724 help
725 This option provides a kernel module that runs torture tests
726 on the RCU infrastructure. The kernel module may be built
727 after the fact on the running kernel to be tested, if desired.
728
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700729 Say Y here if you want RCU torture tests to be built into
730 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800731 Say M if you want the RCU torture tests to build as a module.
732 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700733
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700734config RCU_TORTURE_TEST_RUNNABLE
735 bool "torture tests for RCU runnable by default"
736 depends on RCU_TORTURE_TEST = y
737 default n
738 help
739 This option provides a way to build the RCU torture tests
740 directly into the kernel without them starting up at boot
741 time. You can use /proc/sys/kernel/rcutorture_runnable
742 to manually override this setting. This /proc file is
743 available only when the RCU torture tests have been built
744 into the kernel.
745
746 Say Y here if you want the RCU torture tests to start during
747 boot (you probably don't).
748 Say N here if you want the RCU torture tests to start only
749 after being manually enabled via /proc.
750
Paul E. McKenney2133b5d2008-10-02 16:06:39 -0700751config RCU_CPU_STALL_DETECTOR
Paul E. McKenney67182ae2008-08-10 18:35:38 -0700752 bool "Check for stalled CPUs delaying RCU grace periods"
Paul E. McKenney6b3ef482009-08-22 13:56:53 -0700753 depends on TREE_RCU || TREE_PREEMPT_RCU
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100754 default n
755 help
756 This option causes RCU to printk information on which
757 CPUs are delaying the current grace period, but only when
758 the grace period extends for excessive time periods.
759
760 Say Y if you want RCU to perform such checks.
761
762 Say N if you are unsure.
763
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +0100764config KPROBES_SANITY_TEST
765 bool "Kprobes sanity tests"
766 depends on DEBUG_KERNEL
767 depends on KPROBES
768 default n
769 help
770 This option provides for testing basic kprobes functionality on
771 boot. A sample kprobe, jprobe and kretprobe are inserted and
772 verified for functionality.
773
774 Say N if you are unsure.
775
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100776config BACKTRACE_SELF_TEST
777 tristate "Self test for the backtrace code"
778 depends on DEBUG_KERNEL
779 default n
780 help
781 This option provides a kernel module that can be used to test
782 the kernel stack backtrace code. This option is not useful
783 for distributions or general kernels, but only for kernel
784 developers working on architecture code.
785
Vegard Nossumad118c52008-06-27 18:04:48 +0200786 Note that if you want to also test saved backtraces, you will
787 have to enable STACKTRACE as well.
788
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100789 Say N if you are unsure.
790
Tejun Heo870d6652008-08-25 19:47:25 +0900791config DEBUG_BLOCK_EXT_DEVT
792 bool "Force extended block device numbers and spread them"
793 depends on DEBUG_KERNEL
794 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +0200795 default n
Tejun Heo870d6652008-08-25 19:47:25 +0900796 help
Tejun Heo0e11e342008-10-13 10:46:01 +0200797 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
798 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
799 YOU ARE DOING. Distros, please enable this and fix whatever
800 is broken.
801
Tejun Heo870d6652008-08-25 19:47:25 +0900802 Conventionally, block device numbers are allocated from
803 predetermined contiguous area. However, extended block area
804 may introduce non-contiguous block device numbers. This
805 option forces most block device numbers to be allocated from
806 the extended space and spreads them to discover kernel or
807 userland code paths which assume predetermined contiguous
808 device number allocation.
809
Tejun Heo55dc7db2008-09-01 13:44:35 +0200810 Note that turning on this debug option shuffles all the
811 device numbers for all IDE and SCSI devices including libata
812 ones, so root partition specified using device number
813 directly (via rdev or root=MAJ:MIN) won't work anymore.
814 Textual device names (root=/dev/sdXn) will continue to work.
815
Tejun Heo870d6652008-08-25 19:47:25 +0900816 Say N if you are unsure.
817
Tejun Heo7c756e62009-06-24 15:13:50 +0900818config DEBUG_FORCE_WEAK_PER_CPU
819 bool "Force weak per-cpu definitions"
820 depends on DEBUG_KERNEL
821 help
822 s390 and alpha require percpu variables in modules to be
823 defined weak to work around addressing range issue which
824 puts the following two restrictions on percpu variable
825 definitions.
826
827 1. percpu symbols must be unique whether static or not
828 2. percpu variables can't be defined inside a function
829
830 To ensure that generic code follows the above rules, this
831 option forces all percpu variables to be defined as weak.
832
Ankita Garg8bb31b92006-10-02 02:17:36 -0700833config LKDTM
834 tristate "Linux Kernel Dump Test Tool Module"
Don Mullisbf4735a2006-12-10 02:18:37 -0800835 depends on DEBUG_KERNEL
Ankita Garg8bb31b92006-10-02 02:17:36 -0700836 depends on KPROBES
Chris Snookfddd9cf2008-02-23 15:23:26 -0800837 depends on BLOCK
Ankita Garg8bb31b92006-10-02 02:17:36 -0700838 default n
839 help
840 This module enables testing of the different dumping mechanisms by
841 inducing system failures at predefined crash points.
842 If you don't need it: say N
843 Choose M here to compile this code as a module. The module will be
844 called lkdtm.
845
846 Documentation on how to use the module can be found in
847 drivers/misc/lkdtm.c
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800848
849config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800850 bool "Fault-injection framework"
851 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -0800852 help
853 Provide fault-injection framework.
854 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800855
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800856config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800857 bool "Fault-injection capability for kmalloc"
858 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +0900859 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800860 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800861 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800862
Akinobu Mita933e3122006-12-08 02:39:45 -0800863config FAIL_PAGE_ALLOC
864 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800865 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800866 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800867 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800868
Akinobu Mitac17bb492006-12-08 02:39:46 -0800869config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100870 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -0700871 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -0800872 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800873 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800874
Jens Axboe581d4e22008-09-14 05:56:33 -0700875config FAIL_IO_TIMEOUT
876 bool "Faul-injection capability for faking disk interrupts"
877 depends on FAULT_INJECTION && BLOCK
878 help
879 Provide fault-injection capability on end IO handling. This
880 will make the block layer "forget" an interrupt as configured,
881 thus exercising the error handling.
882
883 Only works with drivers that use the generic timeout handling,
884 for others it wont do anything.
885
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800886config FAULT_INJECTION_DEBUG_FS
887 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800888 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800889 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800890 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -0800891
892config FAULT_INJECTION_STACKTRACE_FILTER
893 bool "stacktrace filter for fault-injection capabilities"
894 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -0700895 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -0800896 select STACKTRACE
Heiko Carstens75ee0342009-04-23 13:58:10 +0200897 select FRAME_POINTER if !PPC && !S390
Akinobu Mita1df49002007-02-20 13:57:56 -0800898 help
899 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700900
Arjan van de Ven97455122008-01-25 21:08:34 +0100901config LATENCYTOP
902 bool "Latency measuring infrastructure"
Heiko Carstens75ee0342009-04-23 13:58:10 +0200903 select FRAME_POINTER if !MIPS && !PPC && !S390
Arjan van de Ven97455122008-01-25 21:08:34 +0100904 select KALLSYMS
905 select KALLSYMS_ALL
906 select STACKTRACE
907 select SCHEDSTATS
908 select SCHED_DEBUG
Heiko Carstensaa7d9352008-02-01 17:45:14 +0100909 depends on HAVE_LATENCYTOP_SUPPORT
Arjan van de Ven97455122008-01-25 21:08:34 +0100910 help
911 Enable this option if you want to use the LatencyTOP tool
912 to find out which userspace is blocking on what kernel operations.
913
Andi Kleen9e94cd32008-08-16 07:53:05 +0200914config SYSCTL_SYSCALL_CHECK
915 bool "Sysctl checks"
916 depends on SYSCTL_SYSCALL
917 ---help---
918 sys_sysctl uses binary paths that have been found challenging
919 to properly maintain and use. This enables checks that help
920 you to keep things correct.
921
Akinobu Mita6a11f752009-03-31 15:23:17 -0700922source mm/Kconfig.debug
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +0200923source kernel/trace/Kconfig
924
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100925config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +0100926 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100927 depends on PCI && X86
928 help
929 If you want to debug problems which hang or crash the kernel early
930 on boot and the crashing machine has a FireWire port, you can use
931 this feature to remotely access the memory of the crashed machine
932 over FireWire. This employs remote DMA as part of the OHCI1394
933 specification which is now the standard for FireWire controllers.
934
935 With remote DMA, you can monitor the printk buffer remotely using
936 firescope and access all memory below 4GB using fireproxy from gdb.
937 Even controlling a kernel debugger is possible using remote DMA.
938
939 Usage:
940
941 If ohci1394_dma=early is used as boot parameter, it will initialize
942 all OHCI1394 controllers which are found in the PCI config space.
943
944 As all changes to the FireWire bus such as enabling and disabling
945 devices cause a bus reset and thereby disable remote DMA for all
946 devices, be sure to have the cable plugged and FireWire enabled on
947 the debugging host before booting the debug target for debugging.
948
949 This code (~1k) is freed after boot. By then, the firewire stack
950 in charge of the OHCI-1394 controllers should be used instead.
951
952 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +0100953
Stefan Richter080de8c2008-02-28 20:54:43 +0100954config FIREWIRE_OHCI_REMOTE_DMA
955 bool "Remote debugging over FireWire with firewire-ohci"
956 depends on FIREWIRE_OHCI
957 help
958 This option lets you use the FireWire bus for remote debugging
959 with help of the firewire-ohci driver. It enables unfiltered
960 remote DMA in firewire-ohci.
961 See Documentation/debugging-via-ohci1394.txt for more information.
962
963 If unsure, say N.
964
Randy Dunlap152de302009-02-20 15:38:47 -0800965config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -0700966 bool "Build targets in Documentation/ tree"
967 depends on HEADERS_CHECK
968 help
969 This option attempts to build objects from the source files in the
970 kernel Documentation/ tree.
971
972 Say N if you are unsure.
973
Jason Barone9d376f2009-02-05 11:51:38 -0500974config DYNAMIC_DEBUG
Jason Baron86151fd2009-02-05 11:53:15 -0500975 bool "Enable dynamic printk() support"
Jason Baron346e15b2008-08-12 16:46:19 -0400976 default n
977 depends on PRINTK
Jason Baron86151fd2009-02-05 11:53:15 -0500978 depends on DEBUG_FS
Jason Baron346e15b2008-08-12 16:46:19 -0400979 help
980
981 Compiles debug level messages into the kernel, which would not
982 otherwise be available at runtime. These messages can then be
Jason Baron86151fd2009-02-05 11:53:15 -0500983 enabled/disabled based on various levels of scope - per source file,
984 function, module, format string, and line number. This mechanism
985 implicitly enables all pr_debug() and dev_dbg() calls. The impact of
986 this compile option is a larger kernel text size of about 2%.
Jason Baron346e15b2008-08-12 16:46:19 -0400987
988 Usage:
989
Jason Baron86151fd2009-02-05 11:53:15 -0500990 Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file,
991 which is contained in the 'debugfs' filesystem. Thus, the debugfs
992 filesystem must first be mounted before making use of this feature.
993 We refer the control file as: <debugfs>/dynamic_debug/ddebug. This
994 file contains a list of the debug statements that can be enabled. The
995 format for each line of the file is:
Jason Baron346e15b2008-08-12 16:46:19 -0400996
Jason Baron86151fd2009-02-05 11:53:15 -0500997 filename:lineno [module]function flags format
Jason Baron346e15b2008-08-12 16:46:19 -0400998
Jason Baron86151fd2009-02-05 11:53:15 -0500999 filename : source file of the debug statement
1000 lineno : line number of the debug statement
1001 module : module that contains the debug statement
1002 function : function that contains the debug statement
1003 flags : 'p' means the line is turned 'on' for printing
1004 format : the format used for the debug statement
Jason Baron346e15b2008-08-12 16:46:19 -04001005
1006 From a live system:
1007
Jason Baron86151fd2009-02-05 11:53:15 -05001008 nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
1009 # filename:lineno [module]function flags format
1010 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
1011 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
1012 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
Jason Baron346e15b2008-08-12 16:46:19 -04001013
Jason Baron86151fd2009-02-05 11:53:15 -05001014 Example usage:
Jason Baron346e15b2008-08-12 16:46:19 -04001015
Jason Baron86151fd2009-02-05 11:53:15 -05001016 // enable the message at line 1603 of file svcsock.c
1017 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
1018 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001019
Jason Baron86151fd2009-02-05 11:53:15 -05001020 // enable all the messages in file svcsock.c
1021 nullarbor:~ # echo -n 'file svcsock.c +p' >
1022 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001023
Jason Baron86151fd2009-02-05 11:53:15 -05001024 // enable all the messages in the NFS server module
1025 nullarbor:~ # echo -n 'module nfsd +p' >
1026 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001027
Jason Baron86151fd2009-02-05 11:53:15 -05001028 // enable all 12 messages in the function svc_process()
1029 nullarbor:~ # echo -n 'func svc_process +p' >
1030 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001031
Jason Baron86151fd2009-02-05 11:53:15 -05001032 // disable all 12 messages in the function svc_process()
1033 nullarbor:~ # echo -n 'func svc_process -p' >
1034 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001035
Jason Baron86151fd2009-02-05 11:53:15 -05001036 See Documentation/dynamic-debug-howto.txt for additional information.
Jason Baron346e15b2008-08-12 16:46:19 -04001037
Joerg Roedel5ee00bd2009-01-09 12:14:24 +01001038config DMA_API_DEBUG
1039 bool "Enable debugging of DMA-API usage"
1040 depends on HAVE_DMA_API_DEBUG
1041 help
1042 Enable this option to debug the use of the DMA API by device drivers.
1043 With this option you will be able to detect common bugs in device
1044 drivers like double-freeing of DMA mappings or freeing mappings that
1045 were never allocated.
1046 This option causes a performance degredation. Use only if you want
1047 to debug device drivers. If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -04001048
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001049source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02001050
1051source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001052
1053source "lib/Kconfig.kmemcheck"