blob: 2f22cf4576dbe719754d329adf18e041c19e2f19 [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 Molnarb642b6d32007-07-09 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 && \
358 (X86 || ARM || PPC || S390)
359
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100360 select DEBUG_FS if SYSFS
361 select STACKTRACE if STACKTRACE_SUPPORT
362 select KALLSYMS
363 help
364 Say Y here if you want to enable the memory leak
365 detector. The memory allocation/freeing is traced in a way
366 similar to the Boehm's conservative garbage collector, the
367 difference being that the orphan objects are not freed but
368 only shown in /sys/kernel/debug/kmemleak. Enabling this
369 feature will introduce an overhead to memory
370 allocations. See Documentation/kmemleak.txt for more
371 details.
372
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100373 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
374 of finding leaks due to the slab objects poisoning.
375
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100376 In order to access the kmemleak file, debugfs needs to be
377 mounted (usually at /sys/kernel/debug).
378
Catalin Marinasa9d90582009-06-25 10:16:11 +0100379config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
380 int "Maximum kmemleak early log entries"
381 depends on DEBUG_KMEMLEAK
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200382 range 200 40000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100383 default 400
384 help
385 Kmemleak must track all the memory allocations to avoid
386 reporting false positives. Since memory may be allocated or
387 freed before kmemleak is initialised, an early log buffer is
388 used to store these actions. If kmemleak reports "early log
389 buffer exceeded", please increase this value.
390
Catalin Marinas0822ee42009-06-11 13:24:14 +0100391config DEBUG_KMEMLEAK_TEST
392 tristate "Simple test for the kernel memory leak detector"
393 depends on DEBUG_KMEMLEAK
394 help
395 Say Y or M here to build a test for the kernel memory leak
396 detector. This option enables a module that explicitly leaks
397 memory.
398
399 If unsure, say N.
400
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401config DEBUG_PREEMPT
402 bool "Debug preemptible kernel"
Kumar Gala01deab92009-10-16 07:21:39 +0000403 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404 default y
405 help
406 If you say Y here then the kernel will use a debug variant of the
407 commonly used smp_processor_id() function and will print warnings
408 if kernel code uses it in a preemption-unsafe way. Also, the kernel
409 will detect preemption count underflows.
410
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700411config DEBUG_RT_MUTEXES
412 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700413 depends on DEBUG_KERNEL && RT_MUTEXES
414 help
415 This allows rt mutex semantics violations and rt mutex related
416 deadlocks (lockups) to be detected and reported automatically.
417
418config DEBUG_PI_LIST
419 bool
420 default y
421 depends on DEBUG_RT_MUTEXES
422
Thomas Gleixner61a87122006-06-27 02:54:56 -0700423config RT_MUTEX_TESTER
424 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700425 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700426 help
427 This option enables a rt-mutex tester.
428
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700430 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 depends on DEBUG_KERNEL
432 help
433 Say Y here and build SMP to catch missing spinlock initialization
434 and certain other kinds of spinlock errors commonly made. This is
435 best used in conjunction with the NMI watchdog so that spinlock
436 deadlocks are also debuggable.
437
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700438config DEBUG_MUTEXES
439 bool "Mutex debugging: basic checks"
440 depends on DEBUG_KERNEL
441 help
442 This feature allows mutex semantics violations to be detected and
443 reported.
444
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700445config DEBUG_LOCK_ALLOC
446 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700447 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700448 select DEBUG_SPINLOCK
449 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700450 select LOCKDEP
451 help
452 This feature will check whether any held lock (spinlock, rwlock,
453 mutex or rwsem) is incorrectly freed by the kernel, via any of the
454 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
455 vfree(), etc.), whether a live lock is incorrectly reinitialized via
456 spin_lock_init()/mutex_init()/etc., or whether there is any lock
457 held during task exit.
458
459config PROVE_LOCKING
460 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700461 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700462 select LOCKDEP
463 select DEBUG_SPINLOCK
464 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700465 select DEBUG_LOCK_ALLOC
466 default n
467 help
468 This feature enables the kernel to prove that all locking
469 that occurs in the kernel runtime is mathematically
470 correct: that under no circumstance could an arbitrary (and
471 not yet triggered) combination of observed locking
472 sequences (on an arbitrary number of CPUs, running an
473 arbitrary number of tasks and interrupt contexts) cause a
474 deadlock.
475
476 In short, this feature enables the kernel to report locking
477 related deadlocks before they actually occur.
478
479 The proof does not depend on how hard and complex a
480 deadlock scenario would be to trigger: how many
481 participant CPUs, tasks and irq-contexts would be needed
482 for it to trigger. The proof also does not depend on
483 timing: if a race and a resulting deadlock is possible
484 theoretically (no matter how unlikely the race scenario
485 is), it will be proven so and will immediately be
486 reported by the kernel (once the event is observed that
487 makes the deadlock theoretically possible).
488
489 If a deadlock is impossible (i.e. the locking rules, as
490 observed by the kernel, are mathematically correct), the
491 kernel reports nothing.
492
493 NOTE: this feature can also be enabled for rwlocks, mutexes
494 and rwsems - in which case all dependencies between these
495 different locking variants are observed and mapped too, and
496 the proof of observed correctness is also maintained for an
497 arbitrary combination of these separate locking variants.
498
499 For more details, see Documentation/lockdep-design.txt.
500
501config LOCKDEP
502 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700503 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700504 select STACKTRACE
Peter Zijlstra00540e52009-06-12 10:04:01 +0200505 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700506 select KALLSYMS
507 select KALLSYMS_ALL
508
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700509config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700510 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700511 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
512 select LOCKDEP
513 select DEBUG_SPINLOCK
514 select DEBUG_MUTEXES
515 select DEBUG_LOCK_ALLOC
516 default n
517 help
518 This feature enables tracking lock contention points
519
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700520 For more details, see Documentation/lockstat.txt
521
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700522config DEBUG_LOCKDEP
523 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700524 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700525 help
526 If you say Y here, the lock dependency engine will do
527 additional runtime checks to debug itself, at the price
528 of more runtime overhead.
529
530config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700531 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700532 bool
533 default y
534 depends on TRACE_IRQFLAGS_SUPPORT
535 depends on PROVE_LOCKING
536
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700538 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 depends on DEBUG_KERNEL
540 help
541 If you say Y here, various routines which may sleep will become very
542 noisy if they are called with a spinlock held.
543
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700544config DEBUG_LOCKING_API_SELFTESTS
545 bool "Locking API boot-time self-tests"
546 depends on DEBUG_KERNEL
547 help
548 Say Y here if you want the kernel to run a short self-test during
549 bootup. The self-test checks whether common types of locking bugs
550 are detected by debugging mechanisms or not. (if you disable
551 lock debugging then those bugs wont be detected of course.)
552 The following locking APIs are covered: spinlocks, rwlocks,
553 mutexes and rwsems.
554
Ingo Molnar8637c092006-07-03 00:24:38 -0700555config STACKTRACE
556 bool
557 depends on STACKTRACE_SUPPORT
558
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559config DEBUG_KOBJECT
560 bool "kobject debugging"
561 depends on DEBUG_KERNEL
562 help
563 If you say Y here, some extra kobject debugging messages will be sent
564 to the syslog.
565
566config DEBUG_HIGHMEM
567 bool "Highmem debugging"
568 depends on DEBUG_KERNEL && HIGHMEM
569 help
570 This options enables addition error checking for high memory systems.
571 Disable for production systems.
572
573config DEBUG_BUGVERBOSE
574 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700575 depends on BUG
David Howellsb920de12008-02-08 04:19:31 -0800576 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
577 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 default !EMBEDDED
579 help
580 Say Y here to make BUG() panics output the file name and line number
581 of the BUG call as well as the EIP and oops trace. This aids
582 debugging but costs about 70-100K of memory.
583
584config DEBUG_INFO
585 bool "Compile the kernel with debug info"
586 depends on DEBUG_KERNEL
587 help
588 If you say Y here the resulting kernel image will include
589 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600590 This adds debug symbols to the kernel and modules (gcc -g), and
591 is needed if you intend to use kernel crashdump or binary object
592 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 Say Y here only if you plan to debug the kernel.
594
595 If unsure, say N.
596
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800597config DEBUG_VM
598 bool "Debug VM"
599 depends on DEBUG_KERNEL
600 help
Nick Piggin13e74442006-01-06 00:10:58 -0800601 Enable this to turn on extended checks in the virtual-memory system
602 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800603
604 If unsure, say N.
605
Jiri Slaby59ea7462008-06-12 13:56:40 +0200606config DEBUG_VIRTUAL
607 bool "Debug VM translations"
608 depends on DEBUG_KERNEL && X86
609 help
610 Enable some costly sanity checks in virtual to page code. This can
611 catch mistakes with virt_to_page() and friends.
612
613 If unsure, say N.
614
David Howells8feae132009-01-08 12:04:47 +0000615config DEBUG_NOMMU_REGIONS
616 bool "Debug the global anon/private NOMMU mapping region tree"
617 depends on DEBUG_KERNEL && !MMU
618 help
619 This option causes the global tree of anonymous and private mapping
620 regions to be regularly checked for invalid topology.
621
Dave Hansenad775f52008-02-15 14:38:01 -0800622config DEBUG_WRITECOUNT
623 bool "Debug filesystem writers count"
624 depends on DEBUG_KERNEL
625 help
626 Enable this to catch wrong use of the writers count in struct
627 vfsmount. This will increase the size of each file struct by
628 32 bits.
629
630 If unsure, say N.
631
Mel Gorman6b74ab92008-07-23 21:26:49 -0700632config DEBUG_MEMORY_INIT
633 bool "Debug memory initialisation" if EMBEDDED
634 default !EMBEDDED
635 help
636 Enable this for additional checks during memory initialisation.
637 The sanity checks verify aspects of the VM such as the memory model
638 and other information provided by the architecture. Verbose
639 information will be printed at KERN_DEBUG loglevel depending
640 on the mminit_loglevel= command-line option.
641
642 If unsure, say Y
643
Dave Jones199a9af2006-09-29 01:59:00 -0700644config DEBUG_LIST
645 bool "Debug linked list manipulation"
646 depends on DEBUG_KERNEL
647 help
648 Enable this to turn on extended checks in the linked-list
649 walking routines.
650
651 If unsure, say N.
652
Jens Axboed6ec0842007-10-22 20:01:06 +0200653config DEBUG_SG
654 bool "Debug SG table operations"
655 depends on DEBUG_KERNEL
656 help
657 Enable this to turn on checks on scatter-gather tables. This can
658 help find problems with drivers that do not properly initialize
659 their sg tables.
660
661 If unsure, say N.
662
Arjan van de Ven1b2439d2008-08-15 15:29:38 -0700663config DEBUG_NOTIFIERS
664 bool "Debug notifier call chains"
665 depends on DEBUG_KERNEL
666 help
667 Enable this to turn on sanity checking for notifier call chains.
668 This is most useful for kernel developers to make sure that
669 modules properly unregister themselves from notifier chains.
670 This is a relatively cheap check but if you care about maximum
671 performance, say N.
672
David Howellse0e81732009-09-02 09:13:40 +0100673config DEBUG_CREDENTIALS
674 bool "Debug credential management"
675 depends on DEBUG_KERNEL
676 help
677 Enable this to turn on some debug checking for credential
678 management. The additional code keeps track of the number of
679 pointers from task_structs to any given cred struct, and checks to
680 see that this number never exceeds the usage count of the cred
681 struct.
682
683 Furthermore, if SELinux is enabled, this also checks that the
684 security pointer in the cred struct is never seen to be invalid.
685
686 If unsure, say N.
687
Jeff Mahoney64dec402009-01-16 13:23:35 -0500688#
689# Select this config option from the architecture Kconfig, if it
690# it is preferred to always offer frame pointers as a config
691# option on the architecture (regardless of KERNEL_DEBUG):
692#
693config ARCH_WANT_FRAME_POINTERS
694 bool
695 help
696
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697config FRAME_POINTER
698 bool "Compile the kernel with frame pointers"
David Howellsb920de12008-02-08 04:19:31 -0800699 depends on DEBUG_KERNEL && \
Heiko Carstens75ee0342009-04-23 13:58:10 +0200700 (CRIS || M68K || M68KNOMMU || FRV || UML || \
Ingo Molnarda4276b2009-01-07 11:05:10 +0100701 AVR32 || SUPERH || BLACKFIN || MN10300) || \
702 ARCH_WANT_FRAME_POINTERS
703 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 help
Ingo Molnarda4276b2009-01-07 11:05:10 +0100705 If you say Y here the resulting kernel image will be slightly
706 larger and slower, but it gives very useful debugging information
707 in case of kernel bugs. (precise oopses/stacktraces/warnings)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700709config BOOT_PRINTK_DELAY
710 bool "Delay each boot printk message by N milliseconds"
711 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
712 help
713 This build option allows you to read kernel boot messages
714 by inserting a short delay after each one. The delay is
715 specified in milliseconds on the kernel command line,
716 using "boot_delay=N".
717
718 It is likely that you would also need to use "lpj=M" to preset
719 the "loops per jiffie" value.
720 See a previous boot log for the "lpj" value to use for your
721 system, and then set "lpj=M" before setting "boot_delay=N".
722 NOTE: Using this option may adversely affect SMP systems.
723 I.e., processors other than the first one may not boot up.
724 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
725 what it believes to be lockup conditions.
726
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800727config RCU_TORTURE_TEST
728 tristate "torture tests for RCU"
729 depends on DEBUG_KERNEL
730 default n
731 help
732 This option provides a kernel module that runs torture tests
733 on the RCU infrastructure. The kernel module may be built
734 after the fact on the running kernel to be tested, if desired.
735
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700736 Say Y here if you want RCU torture tests to be built into
737 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800738 Say M if you want the RCU torture tests to build as a module.
739 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700740
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700741config RCU_TORTURE_TEST_RUNNABLE
742 bool "torture tests for RCU runnable by default"
743 depends on RCU_TORTURE_TEST = y
744 default n
745 help
746 This option provides a way to build the RCU torture tests
747 directly into the kernel without them starting up at boot
748 time. You can use /proc/sys/kernel/rcutorture_runnable
749 to manually override this setting. This /proc file is
750 available only when the RCU torture tests have been built
751 into the kernel.
752
753 Say Y here if you want the RCU torture tests to start during
754 boot (you probably don't).
755 Say N here if you want the RCU torture tests to start only
756 after being manually enabled via /proc.
757
Paul E. McKenney2133b5d2008-10-02 16:06:39 -0700758config RCU_CPU_STALL_DETECTOR
Paul E. McKenney67182ae2008-08-10 18:35:38 -0700759 bool "Check for stalled CPUs delaying RCU grace periods"
Paul E. McKenney6b3ef482009-08-22 13:56:53 -0700760 depends on TREE_RCU || TREE_PREEMPT_RCU
Paul E. McKenney8bfb2f82009-12-02 12:10:16 -0800761 default y
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100762 help
763 This option causes RCU to printk information on which
764 CPUs are delaying the current grace period, but only when
765 the grace period extends for excessive time periods.
766
767 Say Y if you want RCU to perform such checks.
768
769 Say N if you are unsure.
770
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +0100771config KPROBES_SANITY_TEST
772 bool "Kprobes sanity tests"
773 depends on DEBUG_KERNEL
774 depends on KPROBES
775 default n
776 help
777 This option provides for testing basic kprobes functionality on
778 boot. A sample kprobe, jprobe and kretprobe are inserted and
779 verified for functionality.
780
781 Say N if you are unsure.
782
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100783config BACKTRACE_SELF_TEST
784 tristate "Self test for the backtrace code"
785 depends on DEBUG_KERNEL
786 default n
787 help
788 This option provides a kernel module that can be used to test
789 the kernel stack backtrace code. This option is not useful
790 for distributions or general kernels, but only for kernel
791 developers working on architecture code.
792
Vegard Nossumad118c52008-06-27 18:04:48 +0200793 Note that if you want to also test saved backtraces, you will
794 have to enable STACKTRACE as well.
795
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100796 Say N if you are unsure.
797
Tejun Heo870d6652008-08-25 19:47:25 +0900798config DEBUG_BLOCK_EXT_DEVT
799 bool "Force extended block device numbers and spread them"
800 depends on DEBUG_KERNEL
801 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +0200802 default n
Tejun Heo870d6652008-08-25 19:47:25 +0900803 help
Tejun Heo0e11e342008-10-13 10:46:01 +0200804 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
805 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
806 YOU ARE DOING. Distros, please enable this and fix whatever
807 is broken.
808
Tejun Heo870d6652008-08-25 19:47:25 +0900809 Conventionally, block device numbers are allocated from
810 predetermined contiguous area. However, extended block area
811 may introduce non-contiguous block device numbers. This
812 option forces most block device numbers to be allocated from
813 the extended space and spreads them to discover kernel or
814 userland code paths which assume predetermined contiguous
815 device number allocation.
816
Tejun Heo55dc7db2008-09-01 13:44:35 +0200817 Note that turning on this debug option shuffles all the
818 device numbers for all IDE and SCSI devices including libata
819 ones, so root partition specified using device number
820 directly (via rdev or root=MAJ:MIN) won't work anymore.
821 Textual device names (root=/dev/sdXn) will continue to work.
822
Tejun Heo870d6652008-08-25 19:47:25 +0900823 Say N if you are unsure.
824
Tejun Heo7c756e62009-06-24 15:13:50 +0900825config DEBUG_FORCE_WEAK_PER_CPU
826 bool "Force weak per-cpu definitions"
827 depends on DEBUG_KERNEL
828 help
829 s390 and alpha require percpu variables in modules to be
830 defined weak to work around addressing range issue which
831 puts the following two restrictions on percpu variable
832 definitions.
833
834 1. percpu symbols must be unique whether static or not
835 2. percpu variables can't be defined inside a function
836
837 To ensure that generic code follows the above rules, this
838 option forces all percpu variables to be defined as weak.
839
Ankita Garg8bb31b92006-10-02 02:17:36 -0700840config LKDTM
841 tristate "Linux Kernel Dump Test Tool Module"
Don Mullisbf4735a2006-12-10 02:18:37 -0800842 depends on DEBUG_KERNEL
Ankita Garg8bb31b92006-10-02 02:17:36 -0700843 depends on KPROBES
Chris Snookfddd9cf2008-02-23 15:23:26 -0800844 depends on BLOCK
Ankita Garg8bb31b92006-10-02 02:17:36 -0700845 default n
846 help
847 This module enables testing of the different dumping mechanisms by
848 inducing system failures at predefined crash points.
849 If you don't need it: say N
850 Choose M here to compile this code as a module. The module will be
851 called lkdtm.
852
853 Documentation on how to use the module can be found in
854 drivers/misc/lkdtm.c
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800855
856config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800857 bool "Fault-injection framework"
858 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -0800859 help
860 Provide fault-injection framework.
861 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800862
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800863config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800864 bool "Fault-injection capability for kmalloc"
865 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +0900866 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800867 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800868 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800869
Akinobu Mita933e3122006-12-08 02:39:45 -0800870config FAIL_PAGE_ALLOC
871 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800872 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800873 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800874 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800875
Akinobu Mitac17bb492006-12-08 02:39:46 -0800876config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100877 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -0700878 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -0800879 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800880 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800881
Jens Axboe581d4e22008-09-14 05:56:33 -0700882config FAIL_IO_TIMEOUT
883 bool "Faul-injection capability for faking disk interrupts"
884 depends on FAULT_INJECTION && BLOCK
885 help
886 Provide fault-injection capability on end IO handling. This
887 will make the block layer "forget" an interrupt as configured,
888 thus exercising the error handling.
889
890 Only works with drivers that use the generic timeout handling,
891 for others it wont do anything.
892
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800893config FAULT_INJECTION_DEBUG_FS
894 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800895 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800896 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800897 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -0800898
899config FAULT_INJECTION_STACKTRACE_FILTER
900 bool "stacktrace filter for fault-injection capabilities"
901 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -0700902 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -0800903 select STACKTRACE
Heiko Carstens75ee0342009-04-23 13:58:10 +0200904 select FRAME_POINTER if !PPC && !S390
Akinobu Mita1df49002007-02-20 13:57:56 -0800905 help
906 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700907
Arjan van de Ven97455122008-01-25 21:08:34 +0100908config LATENCYTOP
909 bool "Latency measuring infrastructure"
Heiko Carstens75ee0342009-04-23 13:58:10 +0200910 select FRAME_POINTER if !MIPS && !PPC && !S390
Arjan van de Ven97455122008-01-25 21:08:34 +0100911 select KALLSYMS
912 select KALLSYMS_ALL
913 select STACKTRACE
914 select SCHEDSTATS
915 select SCHED_DEBUG
Heiko Carstensaa7d93502008-02-01 17:45:14 +0100916 depends on HAVE_LATENCYTOP_SUPPORT
Arjan van de Ven97455122008-01-25 21:08:34 +0100917 help
918 Enable this option if you want to use the LatencyTOP tool
919 to find out which userspace is blocking on what kernel operations.
920
Andi Kleen9e94cd32008-08-16 07:53:05 +0200921config SYSCTL_SYSCALL_CHECK
922 bool "Sysctl checks"
Eric W. Biederman83ac2012009-04-03 02:22:26 -0700923 depends on SYSCTL
Andi Kleen9e94cd32008-08-16 07:53:05 +0200924 ---help---
925 sys_sysctl uses binary paths that have been found challenging
926 to properly maintain and use. This enables checks that help
927 you to keep things correct.
928
Akinobu Mita6a11f752009-03-31 15:23:17 -0700929source mm/Kconfig.debug
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +0200930source kernel/trace/Kconfig
931
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100932config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +0100933 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100934 depends on PCI && X86
935 help
936 If you want to debug problems which hang or crash the kernel early
937 on boot and the crashing machine has a FireWire port, you can use
938 this feature to remotely access the memory of the crashed machine
939 over FireWire. This employs remote DMA as part of the OHCI1394
940 specification which is now the standard for FireWire controllers.
941
942 With remote DMA, you can monitor the printk buffer remotely using
943 firescope and access all memory below 4GB using fireproxy from gdb.
944 Even controlling a kernel debugger is possible using remote DMA.
945
946 Usage:
947
948 If ohci1394_dma=early is used as boot parameter, it will initialize
949 all OHCI1394 controllers which are found in the PCI config space.
950
951 As all changes to the FireWire bus such as enabling and disabling
952 devices cause a bus reset and thereby disable remote DMA for all
953 devices, be sure to have the cable plugged and FireWire enabled on
954 the debugging host before booting the debug target for debugging.
955
956 This code (~1k) is freed after boot. By then, the firewire stack
957 in charge of the OHCI-1394 controllers should be used instead.
958
959 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +0100960
Stefan Richter080de8c2008-02-28 20:54:43 +0100961config FIREWIRE_OHCI_REMOTE_DMA
962 bool "Remote debugging over FireWire with firewire-ohci"
963 depends on FIREWIRE_OHCI
964 help
965 This option lets you use the FireWire bus for remote debugging
966 with help of the firewire-ohci driver. It enables unfiltered
967 remote DMA in firewire-ohci.
968 See Documentation/debugging-via-ohci1394.txt for more information.
969
970 If unsure, say N.
971
Randy Dunlap152de302009-02-20 15:38:47 -0800972config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -0700973 bool "Build targets in Documentation/ tree"
974 depends on HEADERS_CHECK
975 help
976 This option attempts to build objects from the source files in the
977 kernel Documentation/ tree.
978
979 Say N if you are unsure.
980
Jason Barone9d376f2009-02-05 11:51:38 -0500981config DYNAMIC_DEBUG
Jason Baron86151fd2009-02-05 11:53:15 -0500982 bool "Enable dynamic printk() support"
Jason Baron346e15b2008-08-12 16:46:19 -0400983 default n
984 depends on PRINTK
Jason Baron86151fd2009-02-05 11:53:15 -0500985 depends on DEBUG_FS
Jason Baron346e15b2008-08-12 16:46:19 -0400986 help
987
988 Compiles debug level messages into the kernel, which would not
989 otherwise be available at runtime. These messages can then be
Jason Baron86151fd2009-02-05 11:53:15 -0500990 enabled/disabled based on various levels of scope - per source file,
991 function, module, format string, and line number. This mechanism
992 implicitly enables all pr_debug() and dev_dbg() calls. The impact of
993 this compile option is a larger kernel text size of about 2%.
Jason Baron346e15b2008-08-12 16:46:19 -0400994
995 Usage:
996
Jason Baron86151fd2009-02-05 11:53:15 -0500997 Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file,
998 which is contained in the 'debugfs' filesystem. Thus, the debugfs
999 filesystem must first be mounted before making use of this feature.
1000 We refer the control file as: <debugfs>/dynamic_debug/ddebug. This
1001 file contains a list of the debug statements that can be enabled. The
1002 format for each line of the file is:
Jason Baron346e15b2008-08-12 16:46:19 -04001003
Jason Baron86151fd2009-02-05 11:53:15 -05001004 filename:lineno [module]function flags format
Jason Baron346e15b2008-08-12 16:46:19 -04001005
Jason Baron86151fd2009-02-05 11:53:15 -05001006 filename : source file of the debug statement
1007 lineno : line number of the debug statement
1008 module : module that contains the debug statement
1009 function : function that contains the debug statement
1010 flags : 'p' means the line is turned 'on' for printing
1011 format : the format used for the debug statement
Jason Baron346e15b2008-08-12 16:46:19 -04001012
1013 From a live system:
1014
Jason Baron86151fd2009-02-05 11:53:15 -05001015 nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
1016 # filename:lineno [module]function flags format
1017 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
1018 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
1019 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
Jason Baron346e15b2008-08-12 16:46:19 -04001020
Jason Baron86151fd2009-02-05 11:53:15 -05001021 Example usage:
Jason Baron346e15b2008-08-12 16:46:19 -04001022
Jason Baron86151fd2009-02-05 11:53:15 -05001023 // enable the message at line 1603 of file svcsock.c
1024 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
1025 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001026
Jason Baron86151fd2009-02-05 11:53:15 -05001027 // enable all the messages in file svcsock.c
1028 nullarbor:~ # echo -n 'file svcsock.c +p' >
1029 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001030
Jason Baron86151fd2009-02-05 11:53:15 -05001031 // enable all the messages in the NFS server module
1032 nullarbor:~ # echo -n 'module nfsd +p' >
1033 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001034
Jason Baron86151fd2009-02-05 11:53:15 -05001035 // enable all 12 messages in the function svc_process()
1036 nullarbor:~ # echo -n 'func svc_process +p' >
1037 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001038
Jason Baron86151fd2009-02-05 11:53:15 -05001039 // disable all 12 messages in the function svc_process()
1040 nullarbor:~ # echo -n 'func svc_process -p' >
1041 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -04001042
Jason Baron86151fd2009-02-05 11:53:15 -05001043 See Documentation/dynamic-debug-howto.txt for additional information.
Jason Baron346e15b2008-08-12 16:46:19 -04001044
Joerg Roedel5ee00bd2009-01-09 12:14:24 +01001045config DMA_API_DEBUG
1046 bool "Enable debugging of DMA-API usage"
1047 depends on HAVE_DMA_API_DEBUG
1048 help
1049 Enable this option to debug the use of the DMA API by device drivers.
1050 With this option you will be able to detect common bugs in device
1051 drivers like double-freeing of DMA mappings or freeing mappings that
1052 were never allocated.
1053 This option causes a performance degredation. Use only if you want
1054 to debug device drivers. If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -04001055
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001056source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02001057
1058source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001059
1060source "lib/Kconfig.kmemcheck"