blob: 1fafb4b99c9bb30c37e151a2db441e3cc9c5fb5f [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"
Mike Frysinger1d536612010-03-23 13:35:17 -0700106 depends on UNDEFINED || (BLACKFIN)
107 default y
Sam Ravnborgfa2144b2008-02-15 13:53:11 +0100108 # This option is on purpose disabled for now.
André Goddard Rosaaf901ca2009-11-14 13:09:05 -0200109 # It will be enabled when we are down to a reasonable number
Sam Ravnborgfa2144b2008-02-15 13:53:11 +0100110 # of section mismatch warnings (< 10 for an allyesconfig build)
Sam Ravnborg91341d42008-01-21 21:31:44 +0100111 help
112 The section mismatch analysis checks if there are illegal
113 references from one section to another section.
114 Linux will during link or during runtime drop some sections
115 and any use of code/data previously in these sections will
116 most likely result in an oops.
117 In the code functions and variables are annotated with
118 __init, __devinit etc. (see full list in include/linux/init.h)
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100119 which results in the code/data being placed in specific sections.
120 The section mismatch analysis is always done after a full
121 kernel build but enabling this option will in addition
Sam Ravnborg91341d42008-01-21 21:31:44 +0100122 do the following:
123 - Add the option -fno-inline-functions-called-once to gcc
124 When inlining a function annotated __init in a non-init
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100125 function we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100126 the analysis would not catch the illegal reference.
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100127 This option tells gcc to inline less but will also
Sam Ravnborg91341d42008-01-21 21:31:44 +0100128 result in a larger kernel.
129 - Run the section mismatch analysis for each module/built-in.o
130 When we run the section mismatch analysis on vmlinux.o we
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100131 lose valueble information about where the mismatch was
Sam Ravnborg91341d42008-01-21 21:31:44 +0100132 introduced.
133 Running the analysis for each module/built-in.o file
134 will tell where the mismatch happens much closer to the
135 source. The drawback is that we will report the same
136 mismatch at least twice.
Sam Ravnborg588ccd72008-01-24 21:12:37 +0100137 - Enable verbose reporting from modpost to help solving
138 the section mismatches reported.
Sam Ravnborg91341d42008-01-21 21:31:44 +0100139
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800140config DEBUG_KERNEL
141 bool "Kernel debugging"
142 help
143 Say Y here if you are developing drivers or trying to debug and
144 identify kernel problems.
145
David Woodhousea304e1b2007-02-12 00:52:00 -0800146config DEBUG_SHIRQ
147 bool "Debug shared IRQ handlers"
148 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
149 help
150 Enable this to generate a spurious interrupt as soon as a shared
151 interrupt handler is registered, and just before one is deregistered.
152 Drivers ought to be able to handle interrupts coming in at those
153 points; some don't and need to be caught.
154
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700155config DETECT_SOFTLOCKUP
156 bool "Detect Soft Lockups"
Heiko Carstensdea20a32006-10-11 01:20:44 -0700157 depends on DEBUG_KERNEL && !S390
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700158 default y
159 help
160 Say Y here to enable the kernel to detect "soft lockups",
161 which are bugs that cause the kernel to loop in kernel
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200162 mode for more than 60 seconds, without giving other tasks a
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700163 chance to run.
164
165 When a soft-lockup is detected, the kernel will print the
166 current stack trace (which you should report), but the
167 system will stay locked up. This feature has negligible
168 overhead.
169
170 (Note that "hard lockups" are separate type of bugs that
171 can be detected via the NMI-watchdog, on platforms that
172 support it.)
173
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200174config BOOTPARAM_SOFTLOCKUP_PANIC
175 bool "Panic (Reboot) On Soft Lockups"
176 depends on DETECT_SOFTLOCKUP
177 help
178 Say Y here to enable the kernel to panic on "soft lockups",
179 which are bugs that cause the kernel to loop in kernel
180 mode for more than 60 seconds, without giving other tasks a
181 chance to run.
182
183 The panic can be used in combination with panic_timeout,
184 to cause the system to reboot automatically after a
185 lockup has been detected. This feature is useful for
186 high-availability systems that have uptime guarantees and
187 where a lockup must be resolved ASAP.
188
189 Say N if unsure.
190
191config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
192 int
193 depends on DETECT_SOFTLOCKUP
194 range 0 1
195 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
196 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
197
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800198config DETECT_HUNG_TASK
199 bool "Detect Hung Tasks"
200 depends on DEBUG_KERNEL
Ingo Molnar77d05632009-04-07 08:55:36 +0200201 default DETECT_SOFTLOCKUP
Mandeep Singh Bainese162b392009-01-15 11:08:40 -0800202 help
203 Say Y here to enable the kernel to detect "hung tasks",
204 which are bugs that cause the task to be stuck in
205 uninterruptible "D" state indefinitiley.
206
207 When a hung task is detected, the kernel will print the
208 current stack trace (which you should report), but the
209 task will stay in uninterruptible state. If lockdep is
210 enabled then all held locks will also be reported. This
211 feature has negligible overhead.
212
213config BOOTPARAM_HUNG_TASK_PANIC
214 bool "Panic (Reboot) On Hung Tasks"
215 depends on DETECT_HUNG_TASK
216 help
217 Say Y here to enable the kernel to panic on "hung tasks",
218 which are bugs that cause the kernel to leave a task stuck
219 in uninterruptible "D" state.
220
221 The panic can be used in combination with panic_timeout,
222 to cause the system to reboot automatically after a
223 hung task has been detected. This feature is useful for
224 high-availability systems that have uptime guarantees and
225 where a hung tasks must be resolved ASAP.
226
227 Say N if unsure.
228
229config BOOTPARAM_HUNG_TASK_PANIC_VALUE
230 int
231 depends on DETECT_HUNG_TASK
232 range 0 1
233 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
234 default 1 if BOOTPARAM_HUNG_TASK_PANIC
235
Ingo Molnarb642b6d2007-07-09 18:52:00 +0200236config SCHED_DEBUG
237 bool "Collect scheduler debugging info"
238 depends on DEBUG_KERNEL && PROC_FS
239 default y
240 help
241 If you say Y here, the /proc/sched_debug file will be provided
242 that can help debug the scheduler. The runtime overhead of this
243 option is minimal.
244
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245config SCHEDSTATS
246 bool "Collect scheduler statistics"
247 depends on DEBUG_KERNEL && PROC_FS
248 help
249 If you say Y here, additional code will be inserted into the
250 scheduler and related routines to collect statistics about
251 scheduler behavior and provide them in /proc/schedstat. These
252 stats may be useful for both tuning and debugging the scheduler
253 If you aren't debugging the scheduler or trying to tune a specific
254 application, you can say N to avoid the very slight overhead
255 this adds.
256
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800257config TIMER_STATS
258 bool "Collect kernel timers statistics"
259 depends on DEBUG_KERNEL && PROC_FS
260 help
261 If you say Y here, additional code will be inserted into the
262 timer routines to collect statistics about kernel timers being
263 reprogrammed. The statistics can be read from /proc/timer_stats.
264 The statistics collection is started by writing 1 to /proc/timer_stats,
265 writing 0 stops it. This feature is useful to collect information
Ingo Molnarc1a834d2007-06-01 00:47:16 -0700266 about timer usage patterns in kernel and userspace. This feature
267 is lightweight if enabled in the kernel config but not activated
268 (it defaults to deactivated on bootup and will only be activated
269 if some application like powertop activates it explicitly).
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800270
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700271config DEBUG_OBJECTS
272 bool "Debug object operations"
273 depends on DEBUG_KERNEL
274 help
275 If you say Y here, additional code will be inserted into the
276 kernel to track the life time of various objects and validate
277 the operations on those objects.
278
279config DEBUG_OBJECTS_SELFTEST
280 bool "Debug objects selftest"
281 depends on DEBUG_OBJECTS
282 help
283 This enables the selftest of the object debug code.
284
285config DEBUG_OBJECTS_FREE
286 bool "Debug objects in freed memory"
287 depends on DEBUG_OBJECTS
288 help
289 This enables checks whether a k/v free operation frees an area
290 which contains an object which has not been deactivated
291 properly. This can make kmalloc/kfree-intensive workloads
292 much slower.
293
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700294config DEBUG_OBJECTS_TIMERS
295 bool "Debug timer objects"
296 depends on DEBUG_OBJECTS
297 help
298 If you say Y here, additional code will be inserted into the
299 timer routines to track the life time of timer objects and
300 validate the timer operations.
301
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900302config DEBUG_OBJECTS_WORK
303 bool "Debug work objects"
304 depends on DEBUG_OBJECTS
305 help
306 If you say Y here, additional code will be inserted into the
307 work queue routines to track the life time of work objects and
308 validate the work operations.
309
Ingo Molnar3ae70202008-11-26 10:02:00 +0100310config DEBUG_OBJECTS_ENABLE_DEFAULT
311 int "debug_objects bootup default value (0-1)"
312 range 0 1
313 default "1"
314 depends on DEBUG_OBJECTS
315 help
316 Debug objects boot parameter default value
317
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800319 bool "Debug slab memory allocations"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200320 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 help
322 Say Y here to have the kernel do limited verification on memory
323 allocation as well as poisoning memory on free to catch use of freed
324 memory. This can make kmalloc/kfree-intensive workloads much slower.
325
Al Viro871751e2006-03-25 03:06:39 -0800326config DEBUG_SLAB_LEAK
327 bool "Memory leak debugging"
328 depends on DEBUG_SLAB
329
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700330config SLUB_DEBUG_ON
331 bool "SLUB debugging on by default"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200332 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700333 default n
334 help
335 Boot with debugging on by default. SLUB boots by default with
336 the runtime debug capabilities switched off. Enabling this is
337 equivalent to specifying the "slub_debug" parameter on boot.
338 There is no support for more fine grained debug control like
339 possible with slub_debug=xxx. SLUB debugging may be switched
340 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
341 "slub_debug=-".
342
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800343config SLUB_STATS
344 default n
345 bool "Enable SLUB performance statistics"
Christoph Lameter5b06c8532008-04-14 18:51:34 +0300346 depends on SLUB && SLUB_DEBUG && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800347 help
348 SLUB statistics are useful to debug SLUBs allocation behavior in
349 order find ways to optimize the allocator. This should never be
350 enabled for production use since keeping statistics slows down
351 the allocator by a few percentage points. The slabinfo command
352 supports the determination of the most active slabs to figure
353 out which slabs are relevant to a particular load.
354 Try running: slabinfo -DA
355
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100356config DEBUG_KMEMLEAK
357 bool "Kernel memory leak detector"
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200358 depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
Chris Smith660e2ac2010-01-27 22:03:11 +0900359 (X86 || ARM || PPC || S390 || SUPERH)
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200360
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100361 select DEBUG_FS if SYSFS
362 select STACKTRACE if STACKTRACE_SUPPORT
363 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800364 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100365 help
366 Say Y here if you want to enable the memory leak
367 detector. The memory allocation/freeing is traced in a way
368 similar to the Boehm's conservative garbage collector, the
369 difference being that the orphan objects are not freed but
370 only shown in /sys/kernel/debug/kmemleak. Enabling this
371 feature will introduce an overhead to memory
372 allocations. See Documentation/kmemleak.txt for more
373 details.
374
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100375 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
376 of finding leaks due to the slab objects poisoning.
377
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100378 In order to access the kmemleak file, debugfs needs to be
379 mounted (usually at /sys/kernel/debug).
380
Catalin Marinasa9d90582009-06-25 10:16:11 +0100381config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
382 int "Maximum kmemleak early log entries"
383 depends on DEBUG_KMEMLEAK
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200384 range 200 40000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100385 default 400
386 help
387 Kmemleak must track all the memory allocations to avoid
388 reporting false positives. Since memory may be allocated or
389 freed before kmemleak is initialised, an early log buffer is
390 used to store these actions. If kmemleak reports "early log
391 buffer exceeded", please increase this value.
392
Catalin Marinas0822ee42009-06-11 13:24:14 +0100393config DEBUG_KMEMLEAK_TEST
394 tristate "Simple test for the kernel memory leak detector"
395 depends on DEBUG_KMEMLEAK
396 help
397 Say Y or M here to build a test for the kernel memory leak
398 detector. This option enables a module that explicitly leaks
399 memory.
400
401 If unsure, say N.
402
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403config DEBUG_PREEMPT
404 bool "Debug preemptible kernel"
Kumar Gala01deab92009-10-16 07:21:39 +0000405 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 default y
407 help
408 If you say Y here then the kernel will use a debug variant of the
409 commonly used smp_processor_id() function and will print warnings
410 if kernel code uses it in a preemption-unsafe way. Also, the kernel
411 will detect preemption count underflows.
412
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700413config DEBUG_RT_MUTEXES
414 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700415 depends on DEBUG_KERNEL && RT_MUTEXES
416 help
417 This allows rt mutex semantics violations and rt mutex related
418 deadlocks (lockups) to be detected and reported automatically.
419
420config DEBUG_PI_LIST
421 bool
422 default y
423 depends on DEBUG_RT_MUTEXES
424
Thomas Gleixner61a87122006-06-27 02:54:56 -0700425config RT_MUTEX_TESTER
426 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700427 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700428 help
429 This option enables a rt-mutex tester.
430
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700432 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 depends on DEBUG_KERNEL
434 help
435 Say Y here and build SMP to catch missing spinlock initialization
436 and certain other kinds of spinlock errors commonly made. This is
437 best used in conjunction with the NMI watchdog so that spinlock
438 deadlocks are also debuggable.
439
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700440config DEBUG_MUTEXES
441 bool "Mutex debugging: basic checks"
442 depends on DEBUG_KERNEL
443 help
444 This feature allows mutex semantics violations to be detected and
445 reported.
446
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700447config DEBUG_LOCK_ALLOC
448 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700449 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700450 select DEBUG_SPINLOCK
451 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700452 select LOCKDEP
453 help
454 This feature will check whether any held lock (spinlock, rwlock,
455 mutex or rwsem) is incorrectly freed by the kernel, via any of the
456 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
457 vfree(), etc.), whether a live lock is incorrectly reinitialized via
458 spin_lock_init()/mutex_init()/etc., or whether there is any lock
459 held during task exit.
460
461config PROVE_LOCKING
462 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700463 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700464 select LOCKDEP
465 select DEBUG_SPINLOCK
466 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700467 select DEBUG_LOCK_ALLOC
468 default n
469 help
470 This feature enables the kernel to prove that all locking
471 that occurs in the kernel runtime is mathematically
472 correct: that under no circumstance could an arbitrary (and
473 not yet triggered) combination of observed locking
474 sequences (on an arbitrary number of CPUs, running an
475 arbitrary number of tasks and interrupt contexts) cause a
476 deadlock.
477
478 In short, this feature enables the kernel to report locking
479 related deadlocks before they actually occur.
480
481 The proof does not depend on how hard and complex a
482 deadlock scenario would be to trigger: how many
483 participant CPUs, tasks and irq-contexts would be needed
484 for it to trigger. The proof also does not depend on
485 timing: if a race and a resulting deadlock is possible
486 theoretically (no matter how unlikely the race scenario
487 is), it will be proven so and will immediately be
488 reported by the kernel (once the event is observed that
489 makes the deadlock theoretically possible).
490
491 If a deadlock is impossible (i.e. the locking rules, as
492 observed by the kernel, are mathematically correct), the
493 kernel reports nothing.
494
495 NOTE: this feature can also be enabled for rwlocks, mutexes
496 and rwsems - in which case all dependencies between these
497 different locking variants are observed and mapped too, and
498 the proof of observed correctness is also maintained for an
499 arbitrary combination of these separate locking variants.
500
501 For more details, see Documentation/lockdep-design.txt.
502
Paul E. McKenney632ee202010-02-22 17:04:45 -0800503config PROVE_RCU
504 bool "RCU debugging: prove RCU correctness"
505 depends on PROVE_LOCKING
506 default n
507 help
508 This feature enables lockdep extensions that check for correct
509 use of RCU APIs. This is currently under development. Say Y
510 if you want to debug RCU usage or help work on the PROVE_RCU
511 feature.
512
513 Say N if you are unsure.
514
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700515config LOCKDEP
516 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700517 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700518 select STACKTRACE
Peter Zijlstra00540e52009-06-12 10:04:01 +0200519 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700520 select KALLSYMS
521 select KALLSYMS_ALL
522
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700523config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700524 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700525 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
526 select LOCKDEP
527 select DEBUG_SPINLOCK
528 select DEBUG_MUTEXES
529 select DEBUG_LOCK_ALLOC
530 default n
531 help
532 This feature enables tracking lock contention points
533
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700534 For more details, see Documentation/lockstat.txt
535
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +0100536 This also enables lock events required by "perf lock",
537 subcommand of perf.
538 If you want to use "perf lock", you also need to turn on
539 CONFIG_EVENT_TRACING.
Hitoshi Mitake84c6f882010-02-04 16:08:15 +0900540
541 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +0100542 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
Hitoshi Mitake84c6f882010-02-04 16:08:15 +0900543
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700544config DEBUG_LOCKDEP
545 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700546 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700547 help
548 If you say Y here, the lock dependency engine will do
549 additional runtime checks to debug itself, at the price
550 of more runtime overhead.
551
552config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700553 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700554 bool
555 default y
556 depends on TRACE_IRQFLAGS_SUPPORT
557 depends on PROVE_LOCKING
558
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700560 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 depends on DEBUG_KERNEL
562 help
563 If you say Y here, various routines which may sleep will become very
564 noisy if they are called with a spinlock held.
565
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700566config DEBUG_LOCKING_API_SELFTESTS
567 bool "Locking API boot-time self-tests"
568 depends on DEBUG_KERNEL
569 help
570 Say Y here if you want the kernel to run a short self-test during
571 bootup. The self-test checks whether common types of locking bugs
572 are detected by debugging mechanisms or not. (if you disable
573 lock debugging then those bugs wont be detected of course.)
574 The following locking APIs are covered: spinlocks, rwlocks,
575 mutexes and rwsems.
576
Ingo Molnar8637c092006-07-03 00:24:38 -0700577config STACKTRACE
578 bool
579 depends on STACKTRACE_SUPPORT
580
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581config DEBUG_KOBJECT
582 bool "kobject debugging"
583 depends on DEBUG_KERNEL
584 help
585 If you say Y here, some extra kobject debugging messages will be sent
586 to the syslog.
587
588config DEBUG_HIGHMEM
589 bool "Highmem debugging"
590 depends on DEBUG_KERNEL && HIGHMEM
591 help
592 This options enables addition error checking for high memory systems.
593 Disable for production systems.
594
595config DEBUG_BUGVERBOSE
596 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700597 depends on BUG
David Howellsb920de12008-02-08 04:19:31 -0800598 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
599 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
Alexey Dobriyan8420e7e2009-12-14 18:00:25 -0800600 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 help
602 Say Y here to make BUG() panics output the file name and line number
603 of the BUG call as well as the EIP and oops trace. This aids
604 debugging but costs about 70-100K of memory.
605
606config DEBUG_INFO
607 bool "Compile the kernel with debug info"
608 depends on DEBUG_KERNEL
609 help
610 If you say Y here the resulting kernel image will include
611 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600612 This adds debug symbols to the kernel and modules (gcc -g), and
613 is needed if you intend to use kernel crashdump or binary object
614 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 Say Y here only if you plan to debug the kernel.
616
617 If unsure, say N.
618
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800619config DEBUG_VM
620 bool "Debug VM"
621 depends on DEBUG_KERNEL
622 help
Nick Piggin13e74442006-01-06 00:10:58 -0800623 Enable this to turn on extended checks in the virtual-memory system
624 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800625
626 If unsure, say N.
627
Jiri Slaby59ea7462008-06-12 13:56:40 +0200628config DEBUG_VIRTUAL
629 bool "Debug VM translations"
630 depends on DEBUG_KERNEL && X86
631 help
632 Enable some costly sanity checks in virtual to page code. This can
633 catch mistakes with virt_to_page() and friends.
634
635 If unsure, say N.
636
David Howells8feae132009-01-08 12:04:47 +0000637config DEBUG_NOMMU_REGIONS
638 bool "Debug the global anon/private NOMMU mapping region tree"
639 depends on DEBUG_KERNEL && !MMU
640 help
641 This option causes the global tree of anonymous and private mapping
642 regions to be regularly checked for invalid topology.
643
Dave Hansenad775f52008-02-15 14:38:01 -0800644config DEBUG_WRITECOUNT
645 bool "Debug filesystem writers count"
646 depends on DEBUG_KERNEL
647 help
648 Enable this to catch wrong use of the writers count in struct
649 vfsmount. This will increase the size of each file struct by
650 32 bits.
651
652 If unsure, say N.
653
Mel Gorman6b74ab92008-07-23 21:26:49 -0700654config DEBUG_MEMORY_INIT
655 bool "Debug memory initialisation" if EMBEDDED
656 default !EMBEDDED
657 help
658 Enable this for additional checks during memory initialisation.
659 The sanity checks verify aspects of the VM such as the memory model
660 and other information provided by the architecture. Verbose
661 information will be printed at KERN_DEBUG loglevel depending
662 on the mminit_loglevel= command-line option.
663
664 If unsure, say Y
665
Dave Jones199a9af2006-09-29 01:59:00 -0700666config DEBUG_LIST
667 bool "Debug linked list manipulation"
668 depends on DEBUG_KERNEL
669 help
670 Enable this to turn on extended checks in the linked-list
671 walking routines.
672
673 If unsure, say N.
674
Jens Axboed6ec0842007-10-22 20:01:06 +0200675config DEBUG_SG
676 bool "Debug SG table operations"
677 depends on DEBUG_KERNEL
678 help
679 Enable this to turn on checks on scatter-gather tables. This can
680 help find problems with drivers that do not properly initialize
681 their sg tables.
682
683 If unsure, say N.
684
Arjan van de Ven1b2439d2008-08-15 15:29:38 -0700685config DEBUG_NOTIFIERS
686 bool "Debug notifier call chains"
687 depends on DEBUG_KERNEL
688 help
689 Enable this to turn on sanity checking for notifier call chains.
690 This is most useful for kernel developers to make sure that
691 modules properly unregister themselves from notifier chains.
692 This is a relatively cheap check but if you care about maximum
693 performance, say N.
694
David Howellse0e81732009-09-02 09:13:40 +0100695config DEBUG_CREDENTIALS
696 bool "Debug credential management"
697 depends on DEBUG_KERNEL
698 help
699 Enable this to turn on some debug checking for credential
700 management. The additional code keeps track of the number of
701 pointers from task_structs to any given cred struct, and checks to
702 see that this number never exceeds the usage count of the cred
703 struct.
704
705 Furthermore, if SELinux is enabled, this also checks that the
706 security pointer in the cred struct is never seen to be invalid.
707
708 If unsure, say N.
709
Jeff Mahoney64dec402009-01-16 13:23:35 -0500710#
711# Select this config option from the architecture Kconfig, if it
712# it is preferred to always offer frame pointers as a config
713# option on the architecture (regardless of KERNEL_DEBUG):
714#
715config ARCH_WANT_FRAME_POINTERS
716 bool
717 help
718
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719config FRAME_POINTER
720 bool "Compile the kernel with frame pointers"
David Howellsb920de12008-02-08 04:19:31 -0800721 depends on DEBUG_KERNEL && \
Heiko Carstens75ee0342009-04-23 13:58:10 +0200722 (CRIS || M68K || M68KNOMMU || FRV || UML || \
Ingo Molnarda4276b2009-01-07 11:05:10 +0100723 AVR32 || SUPERH || BLACKFIN || MN10300) || \
724 ARCH_WANT_FRAME_POINTERS
725 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 help
Ingo Molnarda4276b2009-01-07 11:05:10 +0100727 If you say Y here the resulting kernel image will be slightly
728 larger and slower, but it gives very useful debugging information
729 in case of kernel bugs. (precise oopses/stacktraces/warnings)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700731config BOOT_PRINTK_DELAY
732 bool "Delay each boot printk message by N milliseconds"
733 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
734 help
735 This build option allows you to read kernel boot messages
736 by inserting a short delay after each one. The delay is
737 specified in milliseconds on the kernel command line,
738 using "boot_delay=N".
739
740 It is likely that you would also need to use "lpj=M" to preset
741 the "loops per jiffie" value.
742 See a previous boot log for the "lpj" value to use for your
743 system, and then set "lpj=M" before setting "boot_delay=N".
744 NOTE: Using this option may adversely affect SMP systems.
745 I.e., processors other than the first one may not boot up.
746 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
747 what it believes to be lockup conditions.
748
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800749config RCU_TORTURE_TEST
750 tristate "torture tests for RCU"
751 depends on DEBUG_KERNEL
752 default n
753 help
754 This option provides a kernel module that runs torture tests
755 on the RCU infrastructure. The kernel module may be built
756 after the fact on the running kernel to be tested, if desired.
757
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700758 Say Y here if you want RCU torture tests to be built into
759 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800760 Say M if you want the RCU torture tests to build as a module.
761 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700762
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700763config RCU_TORTURE_TEST_RUNNABLE
764 bool "torture tests for RCU runnable by default"
765 depends on RCU_TORTURE_TEST = y
766 default n
767 help
768 This option provides a way to build the RCU torture tests
769 directly into the kernel without them starting up at boot
770 time. You can use /proc/sys/kernel/rcutorture_runnable
771 to manually override this setting. This /proc file is
772 available only when the RCU torture tests have been built
773 into the kernel.
774
775 Say Y here if you want the RCU torture tests to start during
776 boot (you probably don't).
777 Say N here if you want the RCU torture tests to start only
778 after being manually enabled via /proc.
779
Paul E. McKenney2133b5d2008-10-02 16:06:39 -0700780config RCU_CPU_STALL_DETECTOR
Paul E. McKenney67182ae2008-08-10 18:35:38 -0700781 bool "Check for stalled CPUs delaying RCU grace periods"
Paul E. McKenney6b3ef482009-08-22 13:56:53 -0700782 depends on TREE_RCU || TREE_PREEMPT_RCU
Paul E. McKenney8bfb2f82009-12-02 12:10:16 -0800783 default y
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100784 help
785 This option causes RCU to printk information on which
786 CPUs are delaying the current grace period, but only when
787 the grace period extends for excessive time periods.
788
Paul E. McKenney4c540052010-01-14 16:10:57 -0800789 Say N if you want to disable such checks.
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100790
Paul E. McKenney4c540052010-01-14 16:10:57 -0800791 Say Y if you are unsure.
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100792
Paul E. McKenney1ed509a2010-02-22 17:05:05 -0800793config RCU_CPU_STALL_VERBOSE
794 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
795 depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU
796 default n
797 help
798 This option causes RCU to printk detailed per-task information
799 for any tasks that are stalling the current RCU grace period.
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100800
801 Say N if you are unsure.
802
Paul E. McKenney1ed509a2010-02-22 17:05:05 -0800803 Say Y if you want to enable such checks.
804
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +0100805config KPROBES_SANITY_TEST
806 bool "Kprobes sanity tests"
807 depends on DEBUG_KERNEL
808 depends on KPROBES
809 default n
810 help
811 This option provides for testing basic kprobes functionality on
812 boot. A sample kprobe, jprobe and kretprobe are inserted and
813 verified for functionality.
814
815 Say N if you are unsure.
816
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100817config BACKTRACE_SELF_TEST
818 tristate "Self test for the backtrace code"
819 depends on DEBUG_KERNEL
820 default n
821 help
822 This option provides a kernel module that can be used to test
823 the kernel stack backtrace code. This option is not useful
824 for distributions or general kernels, but only for kernel
825 developers working on architecture code.
826
Vegard Nossumad118c52008-06-27 18:04:48 +0200827 Note that if you want to also test saved backtraces, you will
828 have to enable STACKTRACE as well.
829
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100830 Say N if you are unsure.
831
Tejun Heo870d6652008-08-25 19:47:25 +0900832config DEBUG_BLOCK_EXT_DEVT
833 bool "Force extended block device numbers and spread them"
834 depends on DEBUG_KERNEL
835 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +0200836 default n
Tejun Heo870d6652008-08-25 19:47:25 +0900837 help
Tejun Heo0e11e342008-10-13 10:46:01 +0200838 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
839 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
840 YOU ARE DOING. Distros, please enable this and fix whatever
841 is broken.
842
Tejun Heo870d6652008-08-25 19:47:25 +0900843 Conventionally, block device numbers are allocated from
844 predetermined contiguous area. However, extended block area
845 may introduce non-contiguous block device numbers. This
846 option forces most block device numbers to be allocated from
847 the extended space and spreads them to discover kernel or
848 userland code paths which assume predetermined contiguous
849 device number allocation.
850
Tejun Heo55dc7db2008-09-01 13:44:35 +0200851 Note that turning on this debug option shuffles all the
852 device numbers for all IDE and SCSI devices including libata
853 ones, so root partition specified using device number
854 directly (via rdev or root=MAJ:MIN) won't work anymore.
855 Textual device names (root=/dev/sdXn) will continue to work.
856
Tejun Heo870d6652008-08-25 19:47:25 +0900857 Say N if you are unsure.
858
Tejun Heo7c756e62009-06-24 15:13:50 +0900859config DEBUG_FORCE_WEAK_PER_CPU
860 bool "Force weak per-cpu definitions"
861 depends on DEBUG_KERNEL
862 help
863 s390 and alpha require percpu variables in modules to be
864 defined weak to work around addressing range issue which
865 puts the following two restrictions on percpu variable
866 definitions.
867
868 1. percpu symbols must be unique whether static or not
869 2. percpu variables can't be defined inside a function
870
871 To ensure that generic code follows the above rules, this
872 option forces all percpu variables to be defined as weak.
873
Ankita Garg8bb31b92006-10-02 02:17:36 -0700874config LKDTM
875 tristate "Linux Kernel Dump Test Tool Module"
Simon Kagstrom0347af42010-03-05 13:42:49 -0800876 depends on DEBUG_FS
Chris Snookfddd9cf2008-02-23 15:23:26 -0800877 depends on BLOCK
Ankita Garg8bb31b92006-10-02 02:17:36 -0700878 default n
879 help
880 This module enables testing of the different dumping mechanisms by
881 inducing system failures at predefined crash points.
882 If you don't need it: say N
883 Choose M here to compile this code as a module. The module will be
884 called lkdtm.
885
886 Documentation on how to use the module can be found in
Simon Kagstrom0347af42010-03-05 13:42:49 -0800887 Documentation/fault-injection/provoke-crashes.txt
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800888
889config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800890 bool "Fault-injection framework"
891 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -0800892 help
893 Provide fault-injection framework.
894 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800895
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800896config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800897 bool "Fault-injection capability for kmalloc"
898 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +0900899 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800900 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800901 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800902
Akinobu Mita933e3122006-12-08 02:39:45 -0800903config FAIL_PAGE_ALLOC
904 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800905 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800906 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800907 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800908
Akinobu Mitac17bb492006-12-08 02:39:46 -0800909config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100910 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -0700911 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -0800912 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800913 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800914
Jens Axboe581d4e22008-09-14 05:56:33 -0700915config FAIL_IO_TIMEOUT
916 bool "Faul-injection capability for faking disk interrupts"
917 depends on FAULT_INJECTION && BLOCK
918 help
919 Provide fault-injection capability on end IO handling. This
920 will make the block layer "forget" an interrupt as configured,
921 thus exercising the error handling.
922
923 Only works with drivers that use the generic timeout handling,
924 for others it wont do anything.
925
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800926config FAULT_INJECTION_DEBUG_FS
927 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800928 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800929 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800930 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -0800931
932config FAULT_INJECTION_STACKTRACE_FILTER
933 bool "stacktrace filter for fault-injection capabilities"
934 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -0700935 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -0800936 select STACKTRACE
Heiko Carstens75ee0342009-04-23 13:58:10 +0200937 select FRAME_POINTER if !PPC && !S390
Akinobu Mita1df49002007-02-20 13:57:56 -0800938 help
939 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700940
Arjan van de Ven97455122008-01-25 21:08:34 +0100941config LATENCYTOP
942 bool "Latency measuring infrastructure"
Heiko Carstens75ee0342009-04-23 13:58:10 +0200943 select FRAME_POINTER if !MIPS && !PPC && !S390
Arjan van de Ven97455122008-01-25 21:08:34 +0100944 select KALLSYMS
945 select KALLSYMS_ALL
946 select STACKTRACE
947 select SCHEDSTATS
948 select SCHED_DEBUG
Heiko Carstensaa7d9352008-02-01 17:45:14 +0100949 depends on HAVE_LATENCYTOP_SUPPORT
Arjan van de Ven97455122008-01-25 21:08:34 +0100950 help
951 Enable this option if you want to use the LatencyTOP tool
952 to find out which userspace is blocking on what kernel operations.
953
Andi Kleen9e94cd32008-08-16 07:53:05 +0200954config SYSCTL_SYSCALL_CHECK
955 bool "Sysctl checks"
Eric W. Biederman83ac2012009-04-03 02:22:26 -0700956 depends on SYSCTL
Andi Kleen9e94cd32008-08-16 07:53:05 +0200957 ---help---
958 sys_sysctl uses binary paths that have been found challenging
959 to properly maintain and use. This enables checks that help
960 you to keep things correct.
961
Akinobu Mita6a11f752009-03-31 15:23:17 -0700962source mm/Kconfig.debug
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +0200963source kernel/trace/Kconfig
964
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100965config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +0100966 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100967 depends on PCI && X86
968 help
969 If you want to debug problems which hang or crash the kernel early
970 on boot and the crashing machine has a FireWire port, you can use
971 this feature to remotely access the memory of the crashed machine
972 over FireWire. This employs remote DMA as part of the OHCI1394
973 specification which is now the standard for FireWire controllers.
974
975 With remote DMA, you can monitor the printk buffer remotely using
976 firescope and access all memory below 4GB using fireproxy from gdb.
977 Even controlling a kernel debugger is possible using remote DMA.
978
979 Usage:
980
981 If ohci1394_dma=early is used as boot parameter, it will initialize
982 all OHCI1394 controllers which are found in the PCI config space.
983
984 As all changes to the FireWire bus such as enabling and disabling
985 devices cause a bus reset and thereby disable remote DMA for all
986 devices, be sure to have the cable plugged and FireWire enabled on
987 the debugging host before booting the debug target for debugging.
988
989 This code (~1k) is freed after boot. By then, the firewire stack
990 in charge of the OHCI-1394 controllers should be used instead.
991
992 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +0100993
Stefan Richter080de8c2008-02-28 20:54:43 +0100994config FIREWIRE_OHCI_REMOTE_DMA
995 bool "Remote debugging over FireWire with firewire-ohci"
996 depends on FIREWIRE_OHCI
997 help
998 This option lets you use the FireWire bus for remote debugging
999 with help of the firewire-ohci driver. It enables unfiltered
1000 remote DMA in firewire-ohci.
1001 See Documentation/debugging-via-ohci1394.txt for more information.
1002
1003 If unsure, say N.
1004
Randy Dunlap152de302009-02-20 15:38:47 -08001005config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -07001006 bool "Build targets in Documentation/ tree"
1007 depends on HEADERS_CHECK
1008 help
1009 This option attempts to build objects from the source files in the
1010 kernel Documentation/ tree.
1011
1012 Say N if you are unsure.
1013
Jason Barone9d376f2009-02-05 11:51:38 -05001014config DYNAMIC_DEBUG
Jason Baron86151fd2009-02-05 11:53:15 -05001015 bool "Enable dynamic printk() support"
Jason Baron346e15b2008-08-12 16:46:19 -04001016 default n
1017 depends on PRINTK
Jason Baron86151fd2009-02-05 11:53:15 -05001018 depends on DEBUG_FS
Jason Baron346e15b2008-08-12 16:46:19 -04001019 help
1020
1021 Compiles debug level messages into the kernel, which would not
1022 otherwise be available at runtime. These messages can then be
Jason Baron86151fd2009-02-05 11:53:15 -05001023 enabled/disabled based on various levels of scope - per source file,
1024 function, module, format string, and line number. This mechanism
1025 implicitly enables all pr_debug() and dev_dbg() calls. The impact of
1026 this compile option is a larger kernel text size of about 2%.
Jason Baron346e15b2008-08-12 16:46:19 -04001027
1028 Usage:
1029
Jason Baron86151fd2009-02-05 11:53:15 -05001030 Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file,
1031 which is contained in the 'debugfs' filesystem. Thus, the debugfs
1032 filesystem must first be mounted before making use of this feature.
1033 We refer the control file as: <debugfs>/dynamic_debug/ddebug. This
1034 file contains a list of the debug statements that can be enabled. The
1035 format for each line of the file is:
Jason Baron346e15b2008-08-12 16:46:19 -04001036
Jason Baron86151fd2009-02-05 11:53:15 -05001037 filename:lineno [module]function flags format
Jason Baron346e15b2008-08-12 16:46:19 -04001038
Jason Baron86151fd2009-02-05 11:53:15 -05001039 filename : source file of the debug statement
1040 lineno : line number of the debug statement
1041 module : module that contains the debug statement
1042 function : function that contains the debug statement
1043 flags : 'p' means the line is turned 'on' for printing
1044 format : the format used for the debug statement
Jason Baron346e15b2008-08-12 16:46:19 -04001045
1046 From a live system:
1047
Jason Baron86151fd2009-02-05 11:53:15 -05001048 nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
1049 # filename:lineno [module]function flags format
1050 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
1051 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
1052 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
Jason Baron346e15b2008-08-12 16:46:19 -04001053
Jason Baron86151fd2009-02-05 11:53:15 -05001054 Example usage:
Jason Baron346e15b2008-08-12 16:46:19 -04001055
Jason Baron86151fd2009-02-05 11:53:15 -05001056 // enable the message at line 1603 of file svcsock.c
1057 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
1058 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001059
Jason Baron86151fd2009-02-05 11:53:15 -05001060 // enable all the messages in file svcsock.c
1061 nullarbor:~ # echo -n 'file svcsock.c +p' >
1062 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001063
Jason Baron86151fd2009-02-05 11:53:15 -05001064 // enable all the messages in the NFS server module
1065 nullarbor:~ # echo -n 'module nfsd +p' >
1066 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001067
Jason Baron86151fd2009-02-05 11:53:15 -05001068 // enable all 12 messages in the function svc_process()
1069 nullarbor:~ # echo -n 'func svc_process +p' >
1070 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001071
Jason Baron86151fd2009-02-05 11:53:15 -05001072 // disable all 12 messages in the function svc_process()
1073 nullarbor:~ # echo -n 'func svc_process -p' >
1074 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001075
Jason Baron86151fd2009-02-05 11:53:15 -05001076 See Documentation/dynamic-debug-howto.txt for additional information.
Jason Baron346e15b2008-08-12 16:46:19 -04001077
Joerg Roedel5ee00bd2009-01-09 12:14:24 +01001078config DMA_API_DEBUG
1079 bool "Enable debugging of DMA-API usage"
1080 depends on HAVE_DMA_API_DEBUG
1081 help
1082 Enable this option to debug the use of the DMA API by device drivers.
1083 With this option you will be able to detect common bugs in device
1084 drivers like double-freeing of DMA mappings or freeing mappings that
1085 were never allocated.
1086 This option causes a performance degredation. Use only if you want
1087 to debug device drivers. If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -04001088
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001089source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02001090
1091source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001092
1093source "lib/Kconfig.kmemcheck"