blob: b520ec1f33c515d478e3e598a4101b4a8d49f334 [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.
André Goddard Rosaaf901ca2009-11-14 13:09:05 -0200108 # It will be enabled when we are down to a reasonable number
Sam Ravnborgfa2144b2008-02-15 13:53:11 +0100109 # 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
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900301config DEBUG_OBJECTS_WORK
302 bool "Debug work objects"
303 depends on DEBUG_OBJECTS
304 help
305 If you say Y here, additional code will be inserted into the
306 work queue routines to track the life time of work objects and
307 validate the work operations.
308
Ingo Molnar3ae70202008-11-26 10:02:00 +0100309config DEBUG_OBJECTS_ENABLE_DEFAULT
310 int "debug_objects bootup default value (0-1)"
311 range 0 1
312 default "1"
313 depends on DEBUG_OBJECTS
314 help
315 Debug objects boot parameter default value
316
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800318 bool "Debug slab memory allocations"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200319 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 help
321 Say Y here to have the kernel do limited verification on memory
322 allocation as well as poisoning memory on free to catch use of freed
323 memory. This can make kmalloc/kfree-intensive workloads much slower.
324
Al Viro871751e2006-03-25 03:06:39 -0800325config DEBUG_SLAB_LEAK
326 bool "Memory leak debugging"
327 depends on DEBUG_SLAB
328
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700329config SLUB_DEBUG_ON
330 bool "SLUB debugging on by default"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200331 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700332 default n
333 help
334 Boot with debugging on by default. SLUB boots by default with
335 the runtime debug capabilities switched off. Enabling this is
336 equivalent to specifying the "slub_debug" parameter on boot.
337 There is no support for more fine grained debug control like
338 possible with slub_debug=xxx. SLUB debugging may be switched
339 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
340 "slub_debug=-".
341
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800342config SLUB_STATS
343 default n
344 bool "Enable SLUB performance statistics"
Christoph Lameter5b06c8532008-04-14 18:51:34 +0300345 depends on SLUB && SLUB_DEBUG && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800346 help
347 SLUB statistics are useful to debug SLUBs allocation behavior in
348 order find ways to optimize the allocator. This should never be
349 enabled for production use since keeping statistics slows down
350 the allocator by a few percentage points. The slabinfo command
351 supports the determination of the most active slabs to figure
352 out which slabs are relevant to a particular load.
353 Try running: slabinfo -DA
354
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100355config DEBUG_KMEMLEAK
356 bool "Kernel memory leak detector"
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200357 depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
Chris Smith660e2ac2010-01-27 22:03:11 +0900358 (X86 || ARM || PPC || S390 || SUPERH)
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200359
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100360 select DEBUG_FS if SYSFS
361 select STACKTRACE if STACKTRACE_SUPPORT
362 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800363 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100364 help
365 Say Y here if you want to enable the memory leak
366 detector. The memory allocation/freeing is traced in a way
367 similar to the Boehm's conservative garbage collector, the
368 difference being that the orphan objects are not freed but
369 only shown in /sys/kernel/debug/kmemleak. Enabling this
370 feature will introduce an overhead to memory
371 allocations. See Documentation/kmemleak.txt for more
372 details.
373
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100374 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
375 of finding leaks due to the slab objects poisoning.
376
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100377 In order to access the kmemleak file, debugfs needs to be
378 mounted (usually at /sys/kernel/debug).
379
Catalin Marinasa9d90582009-06-25 10:16:11 +0100380config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
381 int "Maximum kmemleak early log entries"
382 depends on DEBUG_KMEMLEAK
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200383 range 200 40000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100384 default 400
385 help
386 Kmemleak must track all the memory allocations to avoid
387 reporting false positives. Since memory may be allocated or
388 freed before kmemleak is initialised, an early log buffer is
389 used to store these actions. If kmemleak reports "early log
390 buffer exceeded", please increase this value.
391
Catalin Marinas0822ee42009-06-11 13:24:14 +0100392config DEBUG_KMEMLEAK_TEST
393 tristate "Simple test for the kernel memory leak detector"
394 depends on DEBUG_KMEMLEAK
395 help
396 Say Y or M here to build a test for the kernel memory leak
397 detector. This option enables a module that explicitly leaks
398 memory.
399
400 If unsure, say N.
401
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402config DEBUG_PREEMPT
403 bool "Debug preemptible kernel"
Kumar Gala01deab92009-10-16 07:21:39 +0000404 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 default y
406 help
407 If you say Y here then the kernel will use a debug variant of the
408 commonly used smp_processor_id() function and will print warnings
409 if kernel code uses it in a preemption-unsafe way. Also, the kernel
410 will detect preemption count underflows.
411
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700412config DEBUG_RT_MUTEXES
413 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700414 depends on DEBUG_KERNEL && RT_MUTEXES
415 help
416 This allows rt mutex semantics violations and rt mutex related
417 deadlocks (lockups) to be detected and reported automatically.
418
419config DEBUG_PI_LIST
420 bool
421 default y
422 depends on DEBUG_RT_MUTEXES
423
Thomas Gleixner61a87122006-06-27 02:54:56 -0700424config RT_MUTEX_TESTER
425 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700426 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700427 help
428 This option enables a rt-mutex tester.
429
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700431 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 depends on DEBUG_KERNEL
433 help
434 Say Y here and build SMP to catch missing spinlock initialization
435 and certain other kinds of spinlock errors commonly made. This is
436 best used in conjunction with the NMI watchdog so that spinlock
437 deadlocks are also debuggable.
438
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700439config DEBUG_MUTEXES
440 bool "Mutex debugging: basic checks"
441 depends on DEBUG_KERNEL
442 help
443 This feature allows mutex semantics violations to be detected and
444 reported.
445
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700446config DEBUG_LOCK_ALLOC
447 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700448 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700449 select DEBUG_SPINLOCK
450 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700451 select LOCKDEP
452 help
453 This feature will check whether any held lock (spinlock, rwlock,
454 mutex or rwsem) is incorrectly freed by the kernel, via any of the
455 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
456 vfree(), etc.), whether a live lock is incorrectly reinitialized via
457 spin_lock_init()/mutex_init()/etc., or whether there is any lock
458 held during task exit.
459
460config PROVE_LOCKING
461 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700462 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700463 select LOCKDEP
464 select DEBUG_SPINLOCK
465 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700466 select DEBUG_LOCK_ALLOC
467 default n
468 help
469 This feature enables the kernel to prove that all locking
470 that occurs in the kernel runtime is mathematically
471 correct: that under no circumstance could an arbitrary (and
472 not yet triggered) combination of observed locking
473 sequences (on an arbitrary number of CPUs, running an
474 arbitrary number of tasks and interrupt contexts) cause a
475 deadlock.
476
477 In short, this feature enables the kernel to report locking
478 related deadlocks before they actually occur.
479
480 The proof does not depend on how hard and complex a
481 deadlock scenario would be to trigger: how many
482 participant CPUs, tasks and irq-contexts would be needed
483 for it to trigger. The proof also does not depend on
484 timing: if a race and a resulting deadlock is possible
485 theoretically (no matter how unlikely the race scenario
486 is), it will be proven so and will immediately be
487 reported by the kernel (once the event is observed that
488 makes the deadlock theoretically possible).
489
490 If a deadlock is impossible (i.e. the locking rules, as
491 observed by the kernel, are mathematically correct), the
492 kernel reports nothing.
493
494 NOTE: this feature can also be enabled for rwlocks, mutexes
495 and rwsems - in which case all dependencies between these
496 different locking variants are observed and mapped too, and
497 the proof of observed correctness is also maintained for an
498 arbitrary combination of these separate locking variants.
499
500 For more details, see Documentation/lockdep-design.txt.
501
Paul E. McKenney632ee202010-02-22 17:04:45 -0800502config PROVE_RCU
503 bool "RCU debugging: prove RCU correctness"
504 depends on PROVE_LOCKING
505 default n
506 help
507 This feature enables lockdep extensions that check for correct
508 use of RCU APIs. This is currently under development. Say Y
509 if you want to debug RCU usage or help work on the PROVE_RCU
510 feature.
511
512 Say N if you are unsure.
513
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700514config LOCKDEP
515 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700516 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700517 select STACKTRACE
Peter Zijlstra00540e52009-06-12 10:04:01 +0200518 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700519 select KALLSYMS
520 select KALLSYMS_ALL
521
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700522config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700523 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700524 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
525 select LOCKDEP
526 select DEBUG_SPINLOCK
527 select DEBUG_MUTEXES
528 select DEBUG_LOCK_ALLOC
529 default n
530 help
531 This feature enables tracking lock contention points
532
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700533 For more details, see Documentation/lockstat.txt
534
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700535config DEBUG_LOCKDEP
536 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700537 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700538 help
539 If you say Y here, the lock dependency engine will do
540 additional runtime checks to debug itself, at the price
541 of more runtime overhead.
542
543config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700544 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700545 bool
546 default y
547 depends on TRACE_IRQFLAGS_SUPPORT
548 depends on PROVE_LOCKING
549
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700551 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 depends on DEBUG_KERNEL
553 help
554 If you say Y here, various routines which may sleep will become very
555 noisy if they are called with a spinlock held.
556
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700557config DEBUG_LOCKING_API_SELFTESTS
558 bool "Locking API boot-time self-tests"
559 depends on DEBUG_KERNEL
560 help
561 Say Y here if you want the kernel to run a short self-test during
562 bootup. The self-test checks whether common types of locking bugs
563 are detected by debugging mechanisms or not. (if you disable
564 lock debugging then those bugs wont be detected of course.)
565 The following locking APIs are covered: spinlocks, rwlocks,
566 mutexes and rwsems.
567
Ingo Molnar8637c092006-07-03 00:24:38 -0700568config STACKTRACE
569 bool
570 depends on STACKTRACE_SUPPORT
571
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572config DEBUG_KOBJECT
573 bool "kobject debugging"
574 depends on DEBUG_KERNEL
575 help
576 If you say Y here, some extra kobject debugging messages will be sent
577 to the syslog.
578
579config DEBUG_HIGHMEM
580 bool "Highmem debugging"
581 depends on DEBUG_KERNEL && HIGHMEM
582 help
583 This options enables addition error checking for high memory systems.
584 Disable for production systems.
585
586config DEBUG_BUGVERBOSE
587 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700588 depends on BUG
David Howellsb920de12008-02-08 04:19:31 -0800589 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
590 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
Alexey Dobriyan8420e7e2009-12-14 18:00:25 -0800591 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 help
593 Say Y here to make BUG() panics output the file name and line number
594 of the BUG call as well as the EIP and oops trace. This aids
595 debugging but costs about 70-100K of memory.
596
597config DEBUG_INFO
598 bool "Compile the kernel with debug info"
599 depends on DEBUG_KERNEL
600 help
601 If you say Y here the resulting kernel image will include
602 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600603 This adds debug symbols to the kernel and modules (gcc -g), and
604 is needed if you intend to use kernel crashdump or binary object
605 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 Say Y here only if you plan to debug the kernel.
607
608 If unsure, say N.
609
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800610config DEBUG_VM
611 bool "Debug VM"
612 depends on DEBUG_KERNEL
613 help
Nick Piggin13e74442006-01-06 00:10:58 -0800614 Enable this to turn on extended checks in the virtual-memory system
615 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800616
617 If unsure, say N.
618
Jiri Slaby59ea7462008-06-12 13:56:40 +0200619config DEBUG_VIRTUAL
620 bool "Debug VM translations"
621 depends on DEBUG_KERNEL && X86
622 help
623 Enable some costly sanity checks in virtual to page code. This can
624 catch mistakes with virt_to_page() and friends.
625
626 If unsure, say N.
627
David Howells8feae132009-01-08 12:04:47 +0000628config DEBUG_NOMMU_REGIONS
629 bool "Debug the global anon/private NOMMU mapping region tree"
630 depends on DEBUG_KERNEL && !MMU
631 help
632 This option causes the global tree of anonymous and private mapping
633 regions to be regularly checked for invalid topology.
634
Dave Hansenad775f52008-02-15 14:38:01 -0800635config DEBUG_WRITECOUNT
636 bool "Debug filesystem writers count"
637 depends on DEBUG_KERNEL
638 help
639 Enable this to catch wrong use of the writers count in struct
640 vfsmount. This will increase the size of each file struct by
641 32 bits.
642
643 If unsure, say N.
644
Mel Gorman6b74ab92008-07-23 21:26:49 -0700645config DEBUG_MEMORY_INIT
646 bool "Debug memory initialisation" if EMBEDDED
647 default !EMBEDDED
648 help
649 Enable this for additional checks during memory initialisation.
650 The sanity checks verify aspects of the VM such as the memory model
651 and other information provided by the architecture. Verbose
652 information will be printed at KERN_DEBUG loglevel depending
653 on the mminit_loglevel= command-line option.
654
655 If unsure, say Y
656
Dave Jones199a9af2006-09-29 01:59:00 -0700657config DEBUG_LIST
658 bool "Debug linked list manipulation"
659 depends on DEBUG_KERNEL
660 help
661 Enable this to turn on extended checks in the linked-list
662 walking routines.
663
664 If unsure, say N.
665
Jens Axboed6ec0842007-10-22 20:01:06 +0200666config DEBUG_SG
667 bool "Debug SG table operations"
668 depends on DEBUG_KERNEL
669 help
670 Enable this to turn on checks on scatter-gather tables. This can
671 help find problems with drivers that do not properly initialize
672 their sg tables.
673
674 If unsure, say N.
675
Arjan van de Ven1b2439d2008-08-15 15:29:38 -0700676config DEBUG_NOTIFIERS
677 bool "Debug notifier call chains"
678 depends on DEBUG_KERNEL
679 help
680 Enable this to turn on sanity checking for notifier call chains.
681 This is most useful for kernel developers to make sure that
682 modules properly unregister themselves from notifier chains.
683 This is a relatively cheap check but if you care about maximum
684 performance, say N.
685
David Howellse0e81732009-09-02 09:13:40 +0100686config DEBUG_CREDENTIALS
687 bool "Debug credential management"
688 depends on DEBUG_KERNEL
689 help
690 Enable this to turn on some debug checking for credential
691 management. The additional code keeps track of the number of
692 pointers from task_structs to any given cred struct, and checks to
693 see that this number never exceeds the usage count of the cred
694 struct.
695
696 Furthermore, if SELinux is enabled, this also checks that the
697 security pointer in the cred struct is never seen to be invalid.
698
699 If unsure, say N.
700
Jeff Mahoney64dec402009-01-16 13:23:35 -0500701#
702# Select this config option from the architecture Kconfig, if it
703# it is preferred to always offer frame pointers as a config
704# option on the architecture (regardless of KERNEL_DEBUG):
705#
706config ARCH_WANT_FRAME_POINTERS
707 bool
708 help
709
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710config FRAME_POINTER
711 bool "Compile the kernel with frame pointers"
David Howellsb920de12008-02-08 04:19:31 -0800712 depends on DEBUG_KERNEL && \
Heiko Carstens75ee0342009-04-23 13:58:10 +0200713 (CRIS || M68K || M68KNOMMU || FRV || UML || \
Ingo Molnarda4276b2009-01-07 11:05:10 +0100714 AVR32 || SUPERH || BLACKFIN || MN10300) || \
715 ARCH_WANT_FRAME_POINTERS
716 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 help
Ingo Molnarda4276b2009-01-07 11:05:10 +0100718 If you say Y here the resulting kernel image will be slightly
719 larger and slower, but it gives very useful debugging information
720 in case of kernel bugs. (precise oopses/stacktraces/warnings)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700722config BOOT_PRINTK_DELAY
723 bool "Delay each boot printk message by N milliseconds"
724 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
725 help
726 This build option allows you to read kernel boot messages
727 by inserting a short delay after each one. The delay is
728 specified in milliseconds on the kernel command line,
729 using "boot_delay=N".
730
731 It is likely that you would also need to use "lpj=M" to preset
732 the "loops per jiffie" value.
733 See a previous boot log for the "lpj" value to use for your
734 system, and then set "lpj=M" before setting "boot_delay=N".
735 NOTE: Using this option may adversely affect SMP systems.
736 I.e., processors other than the first one may not boot up.
737 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
738 what it believes to be lockup conditions.
739
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800740config RCU_TORTURE_TEST
741 tristate "torture tests for RCU"
742 depends on DEBUG_KERNEL
743 default n
744 help
745 This option provides a kernel module that runs torture tests
746 on the RCU infrastructure. The kernel module may be built
747 after the fact on the running kernel to be tested, if desired.
748
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700749 Say Y here if you want RCU torture tests to be built into
750 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800751 Say M if you want the RCU torture tests to build as a module.
752 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700753
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700754config RCU_TORTURE_TEST_RUNNABLE
755 bool "torture tests for RCU runnable by default"
756 depends on RCU_TORTURE_TEST = y
757 default n
758 help
759 This option provides a way to build the RCU torture tests
760 directly into the kernel without them starting up at boot
761 time. You can use /proc/sys/kernel/rcutorture_runnable
762 to manually override this setting. This /proc file is
763 available only when the RCU torture tests have been built
764 into the kernel.
765
766 Say Y here if you want the RCU torture tests to start during
767 boot (you probably don't).
768 Say N here if you want the RCU torture tests to start only
769 after being manually enabled via /proc.
770
Paul E. McKenney2133b5d2008-10-02 16:06:39 -0700771config RCU_CPU_STALL_DETECTOR
Paul E. McKenney67182ae2008-08-10 18:35:38 -0700772 bool "Check for stalled CPUs delaying RCU grace periods"
Paul E. McKenney6b3ef482009-08-22 13:56:53 -0700773 depends on TREE_RCU || TREE_PREEMPT_RCU
Paul E. McKenney8bfb2f82009-12-02 12:10:16 -0800774 default y
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100775 help
776 This option causes RCU to printk information on which
777 CPUs are delaying the current grace period, but only when
778 the grace period extends for excessive time periods.
779
Paul E. McKenney4c540052010-01-14 16:10:57 -0800780 Say N if you want to disable such checks.
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100781
Paul E. McKenney4c540052010-01-14 16:10:57 -0800782 Say Y if you are unsure.
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100783
Paul E. McKenney1ed509a2010-02-22 17:05:05 -0800784config RCU_CPU_STALL_VERBOSE
785 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
786 depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU
787 default n
788 help
789 This option causes RCU to printk detailed per-task information
790 for any tasks that are stalling the current RCU grace period.
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100791
792 Say N if you are unsure.
793
Paul E. McKenney1ed509a2010-02-22 17:05:05 -0800794 Say Y if you want to enable such checks.
795
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +0100796config KPROBES_SANITY_TEST
797 bool "Kprobes sanity tests"
798 depends on DEBUG_KERNEL
799 depends on KPROBES
800 default n
801 help
802 This option provides for testing basic kprobes functionality on
803 boot. A sample kprobe, jprobe and kretprobe are inserted and
804 verified for functionality.
805
806 Say N if you are unsure.
807
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100808config BACKTRACE_SELF_TEST
809 tristate "Self test for the backtrace code"
810 depends on DEBUG_KERNEL
811 default n
812 help
813 This option provides a kernel module that can be used to test
814 the kernel stack backtrace code. This option is not useful
815 for distributions or general kernels, but only for kernel
816 developers working on architecture code.
817
Vegard Nossumad118c52008-06-27 18:04:48 +0200818 Note that if you want to also test saved backtraces, you will
819 have to enable STACKTRACE as well.
820
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100821 Say N if you are unsure.
822
Tejun Heo870d6652008-08-25 19:47:25 +0900823config DEBUG_BLOCK_EXT_DEVT
824 bool "Force extended block device numbers and spread them"
825 depends on DEBUG_KERNEL
826 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +0200827 default n
Tejun Heo870d6652008-08-25 19:47:25 +0900828 help
Tejun Heo0e11e342008-10-13 10:46:01 +0200829 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
830 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
831 YOU ARE DOING. Distros, please enable this and fix whatever
832 is broken.
833
Tejun Heo870d6652008-08-25 19:47:25 +0900834 Conventionally, block device numbers are allocated from
835 predetermined contiguous area. However, extended block area
836 may introduce non-contiguous block device numbers. This
837 option forces most block device numbers to be allocated from
838 the extended space and spreads them to discover kernel or
839 userland code paths which assume predetermined contiguous
840 device number allocation.
841
Tejun Heo55dc7db2008-09-01 13:44:35 +0200842 Note that turning on this debug option shuffles all the
843 device numbers for all IDE and SCSI devices including libata
844 ones, so root partition specified using device number
845 directly (via rdev or root=MAJ:MIN) won't work anymore.
846 Textual device names (root=/dev/sdXn) will continue to work.
847
Tejun Heo870d6652008-08-25 19:47:25 +0900848 Say N if you are unsure.
849
Tejun Heo7c756e62009-06-24 15:13:50 +0900850config DEBUG_FORCE_WEAK_PER_CPU
851 bool "Force weak per-cpu definitions"
852 depends on DEBUG_KERNEL
853 help
854 s390 and alpha require percpu variables in modules to be
855 defined weak to work around addressing range issue which
856 puts the following two restrictions on percpu variable
857 definitions.
858
859 1. percpu symbols must be unique whether static or not
860 2. percpu variables can't be defined inside a function
861
862 To ensure that generic code follows the above rules, this
863 option forces all percpu variables to be defined as weak.
864
Ankita Garg8bb31b92006-10-02 02:17:36 -0700865config LKDTM
866 tristate "Linux Kernel Dump Test Tool Module"
Simon Kagstrom0347af42010-03-05 13:42:49 -0800867 depends on DEBUG_FS
Chris Snookfddd9cf2008-02-23 15:23:26 -0800868 depends on BLOCK
Ankita Garg8bb31b92006-10-02 02:17:36 -0700869 default n
870 help
871 This module enables testing of the different dumping mechanisms by
872 inducing system failures at predefined crash points.
873 If you don't need it: say N
874 Choose M here to compile this code as a module. The module will be
875 called lkdtm.
876
877 Documentation on how to use the module can be found in
Simon Kagstrom0347af42010-03-05 13:42:49 -0800878 Documentation/fault-injection/provoke-crashes.txt
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800879
880config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800881 bool "Fault-injection framework"
882 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -0800883 help
884 Provide fault-injection framework.
885 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800886
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800887config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800888 bool "Fault-injection capability for kmalloc"
889 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +0900890 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800891 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800892 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800893
Akinobu Mita933e3122006-12-08 02:39:45 -0800894config FAIL_PAGE_ALLOC
895 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800896 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800897 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800898 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800899
Akinobu Mitac17bb492006-12-08 02:39:46 -0800900config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100901 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -0700902 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -0800903 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800904 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800905
Jens Axboe581d4e22008-09-14 05:56:33 -0700906config FAIL_IO_TIMEOUT
907 bool "Faul-injection capability for faking disk interrupts"
908 depends on FAULT_INJECTION && BLOCK
909 help
910 Provide fault-injection capability on end IO handling. This
911 will make the block layer "forget" an interrupt as configured,
912 thus exercising the error handling.
913
914 Only works with drivers that use the generic timeout handling,
915 for others it wont do anything.
916
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800917config FAULT_INJECTION_DEBUG_FS
918 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800919 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800920 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800921 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -0800922
923config FAULT_INJECTION_STACKTRACE_FILTER
924 bool "stacktrace filter for fault-injection capabilities"
925 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -0700926 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -0800927 select STACKTRACE
Heiko Carstens75ee0342009-04-23 13:58:10 +0200928 select FRAME_POINTER if !PPC && !S390
Akinobu Mita1df49002007-02-20 13:57:56 -0800929 help
930 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700931
Arjan van de Ven97455122008-01-25 21:08:34 +0100932config LATENCYTOP
933 bool "Latency measuring infrastructure"
Heiko Carstens75ee0342009-04-23 13:58:10 +0200934 select FRAME_POINTER if !MIPS && !PPC && !S390
Arjan van de Ven97455122008-01-25 21:08:34 +0100935 select KALLSYMS
936 select KALLSYMS_ALL
937 select STACKTRACE
938 select SCHEDSTATS
939 select SCHED_DEBUG
Heiko Carstensaa7d9352008-02-01 17:45:14 +0100940 depends on HAVE_LATENCYTOP_SUPPORT
Arjan van de Ven97455122008-01-25 21:08:34 +0100941 help
942 Enable this option if you want to use the LatencyTOP tool
943 to find out which userspace is blocking on what kernel operations.
944
Andi Kleen9e94cd32008-08-16 07:53:05 +0200945config SYSCTL_SYSCALL_CHECK
946 bool "Sysctl checks"
Eric W. Biederman83ac2012009-04-03 02:22:26 -0700947 depends on SYSCTL
Andi Kleen9e94cd32008-08-16 07:53:05 +0200948 ---help---
949 sys_sysctl uses binary paths that have been found challenging
950 to properly maintain and use. This enables checks that help
951 you to keep things correct.
952
Akinobu Mita6a11f752009-03-31 15:23:17 -0700953source mm/Kconfig.debug
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +0200954source kernel/trace/Kconfig
955
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100956config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +0100957 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100958 depends on PCI && X86
959 help
960 If you want to debug problems which hang or crash the kernel early
961 on boot and the crashing machine has a FireWire port, you can use
962 this feature to remotely access the memory of the crashed machine
963 over FireWire. This employs remote DMA as part of the OHCI1394
964 specification which is now the standard for FireWire controllers.
965
966 With remote DMA, you can monitor the printk buffer remotely using
967 firescope and access all memory below 4GB using fireproxy from gdb.
968 Even controlling a kernel debugger is possible using remote DMA.
969
970 Usage:
971
972 If ohci1394_dma=early is used as boot parameter, it will initialize
973 all OHCI1394 controllers which are found in the PCI config space.
974
975 As all changes to the FireWire bus such as enabling and disabling
976 devices cause a bus reset and thereby disable remote DMA for all
977 devices, be sure to have the cable plugged and FireWire enabled on
978 the debugging host before booting the debug target for debugging.
979
980 This code (~1k) is freed after boot. By then, the firewire stack
981 in charge of the OHCI-1394 controllers should be used instead.
982
983 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +0100984
Stefan Richter080de8c2008-02-28 20:54:43 +0100985config FIREWIRE_OHCI_REMOTE_DMA
986 bool "Remote debugging over FireWire with firewire-ohci"
987 depends on FIREWIRE_OHCI
988 help
989 This option lets you use the FireWire bus for remote debugging
990 with help of the firewire-ohci driver. It enables unfiltered
991 remote DMA in firewire-ohci.
992 See Documentation/debugging-via-ohci1394.txt for more information.
993
994 If unsure, say N.
995
Randy Dunlap152de302009-02-20 15:38:47 -0800996config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -0700997 bool "Build targets in Documentation/ tree"
998 depends on HEADERS_CHECK
999 help
1000 This option attempts to build objects from the source files in the
1001 kernel Documentation/ tree.
1002
1003 Say N if you are unsure.
1004
Jason Barone9d376f2009-02-05 11:51:38 -05001005config DYNAMIC_DEBUG
Jason Baron86151fd2009-02-05 11:53:15 -05001006 bool "Enable dynamic printk() support"
Jason Baron346e15b2008-08-12 16:46:19 -04001007 default n
1008 depends on PRINTK
Jason Baron86151fd2009-02-05 11:53:15 -05001009 depends on DEBUG_FS
Jason Baron346e15b2008-08-12 16:46:19 -04001010 help
1011
1012 Compiles debug level messages into the kernel, which would not
1013 otherwise be available at runtime. These messages can then be
Jason Baron86151fd2009-02-05 11:53:15 -05001014 enabled/disabled based on various levels of scope - per source file,
1015 function, module, format string, and line number. This mechanism
1016 implicitly enables all pr_debug() and dev_dbg() calls. The impact of
1017 this compile option is a larger kernel text size of about 2%.
Jason Baron346e15b2008-08-12 16:46:19 -04001018
1019 Usage:
1020
Jason Baron86151fd2009-02-05 11:53:15 -05001021 Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file,
1022 which is contained in the 'debugfs' filesystem. Thus, the debugfs
1023 filesystem must first be mounted before making use of this feature.
1024 We refer the control file as: <debugfs>/dynamic_debug/ddebug. This
1025 file contains a list of the debug statements that can be enabled. The
1026 format for each line of the file is:
Jason Baron346e15b2008-08-12 16:46:19 -04001027
Jason Baron86151fd2009-02-05 11:53:15 -05001028 filename:lineno [module]function flags format
Jason Baron346e15b2008-08-12 16:46:19 -04001029
Jason Baron86151fd2009-02-05 11:53:15 -05001030 filename : source file of the debug statement
1031 lineno : line number of the debug statement
1032 module : module that contains the debug statement
1033 function : function that contains the debug statement
1034 flags : 'p' means the line is turned 'on' for printing
1035 format : the format used for the debug statement
Jason Baron346e15b2008-08-12 16:46:19 -04001036
1037 From a live system:
1038
Jason Baron86151fd2009-02-05 11:53:15 -05001039 nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
1040 # filename:lineno [module]function flags format
1041 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
1042 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
1043 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
Jason Baron346e15b2008-08-12 16:46:19 -04001044
Jason Baron86151fd2009-02-05 11:53:15 -05001045 Example usage:
Jason Baron346e15b2008-08-12 16:46:19 -04001046
Jason Baron86151fd2009-02-05 11:53:15 -05001047 // enable the message at line 1603 of file svcsock.c
1048 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
1049 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001050
Jason Baron86151fd2009-02-05 11:53:15 -05001051 // enable all the messages in file svcsock.c
1052 nullarbor:~ # echo -n 'file svcsock.c +p' >
1053 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001054
Jason Baron86151fd2009-02-05 11:53:15 -05001055 // enable all the messages in the NFS server module
1056 nullarbor:~ # echo -n 'module nfsd +p' >
1057 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001058
Jason Baron86151fd2009-02-05 11:53:15 -05001059 // enable all 12 messages in the function svc_process()
1060 nullarbor:~ # echo -n 'func svc_process +p' >
1061 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001062
Jason Baron86151fd2009-02-05 11:53:15 -05001063 // disable all 12 messages in the function svc_process()
1064 nullarbor:~ # echo -n 'func svc_process -p' >
1065 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001066
Jason Baron86151fd2009-02-05 11:53:15 -05001067 See Documentation/dynamic-debug-howto.txt for additional information.
Jason Baron346e15b2008-08-12 16:46:19 -04001068
Joerg Roedel5ee00bd2009-01-09 12:14:24 +01001069config DMA_API_DEBUG
1070 bool "Enable debugging of DMA-API usage"
1071 depends on HAVE_DMA_API_DEBUG
1072 help
1073 Enable this option to debug the use of the DMA API by device drivers.
1074 With this option you will be able to detect common bugs in device
1075 drivers like double-freeing of DMA mappings or freeing mappings that
1076 were never allocated.
1077 This option causes a performance degredation. Use only if you want
1078 to debug device drivers. If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -04001079
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001080source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02001081
1082source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001083
1084source "lib/Kconfig.kmemcheck"