blob: 9638d99644afe4b5ff04d4ac8fcd194d1b67f614 [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
Arjan van de Venf71d20e2006-06-28 04:26:45 -070053config UNUSED_SYMBOLS
54 bool "Enable unused/obsolete exported symbols"
55 default y if X86
56 help
57 Unused but exported symbols make the kernel needlessly bigger. For
58 that reason most of these unused exports will soon be removed. This
59 option is provided temporarily to provide a transition period in case
60 some external kernel module needs one of these symbols anyway. If you
61 encounter such a case in your module, consider if you are actually
62 using the right API. (rationale: since nobody in the kernel is using
63 this in a module, there is a pretty good chance it's actually the
64 wrong interface to use). If you really need the symbol, please send a
65 mail to the linux kernel mailing list mentioning the symbol and why
66 you really need it, and what the merge plan to the mainline kernel for
67 your module is.
68
Don Mullisbf4735a2006-12-10 02:18:37 -080069config DEBUG_FS
70 bool "Debug Filesystem"
71 depends on SYSFS
72 help
73 debugfs is a virtual file system that kernel developers use to put
74 debugging files into. Enable this option to be able to read and
75 write to these files.
76
Robert P. J. Dayff543332008-05-20 00:06:00 +020077 For detailed documentation on the debugfs API, see
78 Documentation/DocBook/filesystems.
79
Don Mullisbf4735a2006-12-10 02:18:37 -080080 If unsure, say N.
81
82config HEADERS_CHECK
83 bool "Run 'make headers_check' when building vmlinux"
84 depends on !UML
85 help
86 This option will extract the user-visible kernel headers whenever
87 building the kernel, and will run basic sanity checks on them to
88 ensure that exported files do not attempt to include files which
89 were not exported, etc.
90
91 If you're making modifications to header files which are
92 relevant for userspace, say 'Y', and check the headers
93 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
94 your build tree), to make sure they're suitable.
95
Sam Ravnborg91341d42008-01-21 21:31:44 +010096config DEBUG_SECTION_MISMATCH
97 bool "Enable full Section mismatch analysis"
Sam Ravnborge5f95c82008-02-02 18:57:18 +010098 depends on UNDEFINED
Sam Ravnborgfa2144b2008-02-15 13:53:11 +010099 # This option is on purpose disabled for now.
100 # It will be enabled when we are down to a resonable number
101 # of section mismatch warnings (< 10 for an allyesconfig build)
Sam Ravnborg91341d42008-01-21 21:31:44 +0100102 help
103 The section mismatch analysis checks if there are illegal
104 references from one section to another section.
105 Linux will during link or during runtime drop some sections
106 and any use of code/data previously in these sections will
107 most likely result in an oops.
108 In the code functions and variables are annotated with
109 __init, __devinit etc. (see full list in include/linux/init.h)
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100110 which results in the code/data being placed in specific sections.
111 The section mismatch analysis is always done after a full
112 kernel build but enabling this option will in addition
Sam Ravnborg91341d42008-01-21 21:31:44 +0100113 do the following:
114 - Add the option -fno-inline-functions-called-once to gcc
115 When inlining a function annotated __init in a non-init
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100116 function we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100117 the analysis would not catch the illegal reference.
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100118 This option tells gcc to inline less but will also
Sam Ravnborg91341d42008-01-21 21:31:44 +0100119 result in a larger kernel.
120 - Run the section mismatch analysis for each module/built-in.o
121 When we run the section mismatch analysis on vmlinux.o we
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100122 lose valueble information about where the mismatch was
Sam Ravnborg91341d42008-01-21 21:31:44 +0100123 introduced.
124 Running the analysis for each module/built-in.o file
125 will tell where the mismatch happens much closer to the
126 source. The drawback is that we will report the same
127 mismatch at least twice.
Sam Ravnborg588ccd72008-01-24 21:12:37 +0100128 - Enable verbose reporting from modpost to help solving
129 the section mismatches reported.
Sam Ravnborg91341d42008-01-21 21:31:44 +0100130
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800131config DEBUG_KERNEL
132 bool "Kernel debugging"
133 help
134 Say Y here if you are developing drivers or trying to debug and
135 identify kernel problems.
136
David Woodhousea304e1b2007-02-12 00:52:00 -0800137config DEBUG_SHIRQ
138 bool "Debug shared IRQ handlers"
139 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
140 help
141 Enable this to generate a spurious interrupt as soon as a shared
142 interrupt handler is registered, and just before one is deregistered.
143 Drivers ought to be able to handle interrupts coming in at those
144 points; some don't and need to be caught.
145
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700146config DETECT_SOFTLOCKUP
147 bool "Detect Soft Lockups"
Heiko Carstensdea20a32006-10-11 01:20:44 -0700148 depends on DEBUG_KERNEL && !S390
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700149 default y
150 help
151 Say Y here to enable the kernel to detect "soft lockups",
152 which are bugs that cause the kernel to loop in kernel
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200153 mode for more than 60 seconds, without giving other tasks a
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700154 chance to run.
155
156 When a soft-lockup is detected, the kernel will print the
157 current stack trace (which you should report), but the
158 system will stay locked up. This feature has negligible
159 overhead.
160
161 (Note that "hard lockups" are separate type of bugs that
162 can be detected via the NMI-watchdog, on platforms that
163 support it.)
164
Ingo Molnar9c44bc02008-05-12 21:21:04 +0200165config BOOTPARAM_SOFTLOCKUP_PANIC
166 bool "Panic (Reboot) On Soft Lockups"
167 depends on DETECT_SOFTLOCKUP
168 help
169 Say Y here to enable the kernel to panic on "soft lockups",
170 which are bugs that cause the kernel to loop in kernel
171 mode for more than 60 seconds, without giving other tasks a
172 chance to run.
173
174 The panic can be used in combination with panic_timeout,
175 to cause the system to reboot automatically after a
176 lockup has been detected. This feature is useful for
177 high-availability systems that have uptime guarantees and
178 where a lockup must be resolved ASAP.
179
180 Say N if unsure.
181
182config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
183 int
184 depends on DETECT_SOFTLOCKUP
185 range 0 1
186 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
187 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
188
Ingo Molnarb642b6d2007-07-09 18:52:00 +0200189config SCHED_DEBUG
190 bool "Collect scheduler debugging info"
191 depends on DEBUG_KERNEL && PROC_FS
192 default y
193 help
194 If you say Y here, the /proc/sched_debug file will be provided
195 that can help debug the scheduler. The runtime overhead of this
196 option is minimal.
197
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198config SCHEDSTATS
199 bool "Collect scheduler statistics"
200 depends on DEBUG_KERNEL && PROC_FS
201 help
202 If you say Y here, additional code will be inserted into the
203 scheduler and related routines to collect statistics about
204 scheduler behavior and provide them in /proc/schedstat. These
205 stats may be useful for both tuning and debugging the scheduler
206 If you aren't debugging the scheduler or trying to tune a specific
207 application, you can say N to avoid the very slight overhead
208 this adds.
209
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800210config TIMER_STATS
211 bool "Collect kernel timers statistics"
212 depends on DEBUG_KERNEL && PROC_FS
213 help
214 If you say Y here, additional code will be inserted into the
215 timer routines to collect statistics about kernel timers being
216 reprogrammed. The statistics can be read from /proc/timer_stats.
217 The statistics collection is started by writing 1 to /proc/timer_stats,
218 writing 0 stops it. This feature is useful to collect information
Ingo Molnarc1a834d2007-06-01 00:47:16 -0700219 about timer usage patterns in kernel and userspace. This feature
220 is lightweight if enabled in the kernel config but not activated
221 (it defaults to deactivated on bootup and will only be activated
222 if some application like powertop activates it explicitly).
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800223
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700224config DEBUG_OBJECTS
225 bool "Debug object operations"
226 depends on DEBUG_KERNEL
227 help
228 If you say Y here, additional code will be inserted into the
229 kernel to track the life time of various objects and validate
230 the operations on those objects.
231
232config DEBUG_OBJECTS_SELFTEST
233 bool "Debug objects selftest"
234 depends on DEBUG_OBJECTS
235 help
236 This enables the selftest of the object debug code.
237
238config DEBUG_OBJECTS_FREE
239 bool "Debug objects in freed memory"
240 depends on DEBUG_OBJECTS
241 help
242 This enables checks whether a k/v free operation frees an area
243 which contains an object which has not been deactivated
244 properly. This can make kmalloc/kfree-intensive workloads
245 much slower.
246
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700247config DEBUG_OBJECTS_TIMERS
248 bool "Debug timer objects"
249 depends on DEBUG_OBJECTS
250 help
251 If you say Y here, additional code will be inserted into the
252 timer routines to track the life time of timer objects and
253 validate the timer operations.
254
Ingo Molnar3ae70202008-11-26 10:02:00 +0100255config DEBUG_OBJECTS_ENABLE_DEFAULT
256 int "debug_objects bootup default value (0-1)"
257 range 0 1
258 default "1"
259 depends on DEBUG_OBJECTS
260 help
261 Debug objects boot parameter default value
262
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800264 bool "Debug slab memory allocations"
Ingo Molnar50dd26b2006-01-08 01:01:42 -0800265 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 help
267 Say Y here to have the kernel do limited verification on memory
268 allocation as well as poisoning memory on free to catch use of freed
269 memory. This can make kmalloc/kfree-intensive workloads much slower.
270
Al Viro871751e2006-03-25 03:06:39 -0800271config DEBUG_SLAB_LEAK
272 bool "Memory leak debugging"
273 depends on DEBUG_SLAB
274
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700275config SLUB_DEBUG_ON
276 bool "SLUB debugging on by default"
277 depends on SLUB && SLUB_DEBUG
278 default n
279 help
280 Boot with debugging on by default. SLUB boots by default with
281 the runtime debug capabilities switched off. Enabling this is
282 equivalent to specifying the "slub_debug" parameter on boot.
283 There is no support for more fine grained debug control like
284 possible with slub_debug=xxx. SLUB debugging may be switched
285 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
286 "slub_debug=-".
287
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800288config SLUB_STATS
289 default n
290 bool "Enable SLUB performance statistics"
Christoph Lameter5b06c8532008-04-14 18:51:34 +0300291 depends on SLUB && SLUB_DEBUG && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800292 help
293 SLUB statistics are useful to debug SLUBs allocation behavior in
294 order find ways to optimize the allocator. This should never be
295 enabled for production use since keeping statistics slows down
296 the allocator by a few percentage points. The slabinfo command
297 supports the determination of the most active slabs to figure
298 out which slabs are relevant to a particular load.
299 Try running: slabinfo -DA
300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301config DEBUG_PREEMPT
302 bool "Debug preemptible kernel"
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100303 depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 default y
305 help
306 If you say Y here then the kernel will use a debug variant of the
307 commonly used smp_processor_id() function and will print warnings
308 if kernel code uses it in a preemption-unsafe way. Also, the kernel
309 will detect preemption count underflows.
310
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700311config DEBUG_RT_MUTEXES
312 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700313 depends on DEBUG_KERNEL && RT_MUTEXES
314 help
315 This allows rt mutex semantics violations and rt mutex related
316 deadlocks (lockups) to be detected and reported automatically.
317
318config DEBUG_PI_LIST
319 bool
320 default y
321 depends on DEBUG_RT_MUTEXES
322
Thomas Gleixner61a87122006-06-27 02:54:56 -0700323config RT_MUTEX_TESTER
324 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700325 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700326 help
327 This option enables a rt-mutex tester.
328
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700330 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 depends on DEBUG_KERNEL
332 help
333 Say Y here and build SMP to catch missing spinlock initialization
334 and certain other kinds of spinlock errors commonly made. This is
335 best used in conjunction with the NMI watchdog so that spinlock
336 deadlocks are also debuggable.
337
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700338config DEBUG_MUTEXES
339 bool "Mutex debugging: basic checks"
340 depends on DEBUG_KERNEL
341 help
342 This feature allows mutex semantics violations to be detected and
343 reported.
344
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700345config DEBUG_LOCK_ALLOC
346 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700347 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700348 select DEBUG_SPINLOCK
349 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700350 select LOCKDEP
351 help
352 This feature will check whether any held lock (spinlock, rwlock,
353 mutex or rwsem) is incorrectly freed by the kernel, via any of the
354 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
355 vfree(), etc.), whether a live lock is incorrectly reinitialized via
356 spin_lock_init()/mutex_init()/etc., or whether there is any lock
357 held during task exit.
358
359config PROVE_LOCKING
360 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700361 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700362 select LOCKDEP
363 select DEBUG_SPINLOCK
364 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700365 select DEBUG_LOCK_ALLOC
366 default n
367 help
368 This feature enables the kernel to prove that all locking
369 that occurs in the kernel runtime is mathematically
370 correct: that under no circumstance could an arbitrary (and
371 not yet triggered) combination of observed locking
372 sequences (on an arbitrary number of CPUs, running an
373 arbitrary number of tasks and interrupt contexts) cause a
374 deadlock.
375
376 In short, this feature enables the kernel to report locking
377 related deadlocks before they actually occur.
378
379 The proof does not depend on how hard and complex a
380 deadlock scenario would be to trigger: how many
381 participant CPUs, tasks and irq-contexts would be needed
382 for it to trigger. The proof also does not depend on
383 timing: if a race and a resulting deadlock is possible
384 theoretically (no matter how unlikely the race scenario
385 is), it will be proven so and will immediately be
386 reported by the kernel (once the event is observed that
387 makes the deadlock theoretically possible).
388
389 If a deadlock is impossible (i.e. the locking rules, as
390 observed by the kernel, are mathematically correct), the
391 kernel reports nothing.
392
393 NOTE: this feature can also be enabled for rwlocks, mutexes
394 and rwsems - in which case all dependencies between these
395 different locking variants are observed and mapped too, and
396 the proof of observed correctness is also maintained for an
397 arbitrary combination of these separate locking variants.
398
399 For more details, see Documentation/lockdep-design.txt.
400
401config LOCKDEP
402 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700403 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700404 select STACKTRACE
Catalin Marinasadf8b372009-02-12 13:56:34 +0100405 select FRAME_POINTER if !X86 && !MIPS && !PPC && !ARM_UNWIND
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700406 select KALLSYMS
407 select KALLSYMS_ALL
408
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700409config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700410 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700411 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
412 select LOCKDEP
413 select DEBUG_SPINLOCK
414 select DEBUG_MUTEXES
415 select DEBUG_LOCK_ALLOC
416 default n
417 help
418 This feature enables tracking lock contention points
419
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700420 For more details, see Documentation/lockstat.txt
421
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700422config DEBUG_LOCKDEP
423 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700424 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700425 help
426 If you say Y here, the lock dependency engine will do
427 additional runtime checks to debug itself, at the price
428 of more runtime overhead.
429
430config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700431 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700432 bool
433 default y
434 depends on TRACE_IRQFLAGS_SUPPORT
435 depends on PROVE_LOCKING
436
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700438 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 depends on DEBUG_KERNEL
440 help
441 If you say Y here, various routines which may sleep will become very
442 noisy if they are called with a spinlock held.
443
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700444config DEBUG_LOCKING_API_SELFTESTS
445 bool "Locking API boot-time self-tests"
446 depends on DEBUG_KERNEL
447 help
448 Say Y here if you want the kernel to run a short self-test during
449 bootup. The self-test checks whether common types of locking bugs
450 are detected by debugging mechanisms or not. (if you disable
451 lock debugging then those bugs wont be detected of course.)
452 The following locking APIs are covered: spinlocks, rwlocks,
453 mutexes and rwsems.
454
Ingo Molnar8637c092006-07-03 00:24:38 -0700455config STACKTRACE
456 bool
457 depends on STACKTRACE_SUPPORT
458
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459config DEBUG_KOBJECT
460 bool "kobject debugging"
461 depends on DEBUG_KERNEL
462 help
463 If you say Y here, some extra kobject debugging messages will be sent
464 to the syslog.
465
466config DEBUG_HIGHMEM
467 bool "Highmem debugging"
468 depends on DEBUG_KERNEL && HIGHMEM
469 help
470 This options enables addition error checking for high memory systems.
471 Disable for production systems.
472
473config DEBUG_BUGVERBOSE
474 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700475 depends on BUG
David Howellsb920de12008-02-08 04:19:31 -0800476 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
477 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 default !EMBEDDED
479 help
480 Say Y here to make BUG() panics output the file name and line number
481 of the BUG call as well as the EIP and oops trace. This aids
482 debugging but costs about 70-100K of memory.
483
484config DEBUG_INFO
485 bool "Compile the kernel with debug info"
486 depends on DEBUG_KERNEL
487 help
488 If you say Y here the resulting kernel image will include
489 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600490 This adds debug symbols to the kernel and modules (gcc -g), and
491 is needed if you intend to use kernel crashdump or binary object
492 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493 Say Y here only if you plan to debug the kernel.
494
495 If unsure, say N.
496
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800497config DEBUG_VM
498 bool "Debug VM"
499 depends on DEBUG_KERNEL
500 help
Nick Piggin13e74442006-01-06 00:10:58 -0800501 Enable this to turn on extended checks in the virtual-memory system
502 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800503
504 If unsure, say N.
505
Jiri Slaby59ea7462008-06-12 13:56:40 +0200506config DEBUG_VIRTUAL
507 bool "Debug VM translations"
508 depends on DEBUG_KERNEL && X86
509 help
510 Enable some costly sanity checks in virtual to page code. This can
511 catch mistakes with virt_to_page() and friends.
512
513 If unsure, say N.
514
David Howells8feae132009-01-08 12:04:47 +0000515config DEBUG_NOMMU_REGIONS
516 bool "Debug the global anon/private NOMMU mapping region tree"
517 depends on DEBUG_KERNEL && !MMU
518 help
519 This option causes the global tree of anonymous and private mapping
520 regions to be regularly checked for invalid topology.
521
Dave Hansenad775f52008-02-15 14:38:01 -0800522config DEBUG_WRITECOUNT
523 bool "Debug filesystem writers count"
524 depends on DEBUG_KERNEL
525 help
526 Enable this to catch wrong use of the writers count in struct
527 vfsmount. This will increase the size of each file struct by
528 32 bits.
529
530 If unsure, say N.
531
Mel Gorman6b74ab92008-07-23 21:26:49 -0700532config DEBUG_MEMORY_INIT
533 bool "Debug memory initialisation" if EMBEDDED
534 default !EMBEDDED
535 help
536 Enable this for additional checks during memory initialisation.
537 The sanity checks verify aspects of the VM such as the memory model
538 and other information provided by the architecture. Verbose
539 information will be printed at KERN_DEBUG loglevel depending
540 on the mminit_loglevel= command-line option.
541
542 If unsure, say Y
543
Dave Jones199a9af2006-09-29 01:59:00 -0700544config DEBUG_LIST
545 bool "Debug linked list manipulation"
546 depends on DEBUG_KERNEL
547 help
548 Enable this to turn on extended checks in the linked-list
549 walking routines.
550
551 If unsure, say N.
552
Jens Axboed6ec0842007-10-22 20:01:06 +0200553config DEBUG_SG
554 bool "Debug SG table operations"
555 depends on DEBUG_KERNEL
556 help
557 Enable this to turn on checks on scatter-gather tables. This can
558 help find problems with drivers that do not properly initialize
559 their sg tables.
560
561 If unsure, say N.
562
Arjan van de Ven1b2439d2008-08-15 15:29:38 -0700563config DEBUG_NOTIFIERS
564 bool "Debug notifier call chains"
565 depends on DEBUG_KERNEL
566 help
567 Enable this to turn on sanity checking for notifier call chains.
568 This is most useful for kernel developers to make sure that
569 modules properly unregister themselves from notifier chains.
570 This is a relatively cheap check but if you care about maximum
571 performance, say N.
572
Jeff Mahoney64dec402009-01-16 13:23:35 -0500573#
574# Select this config option from the architecture Kconfig, if it
575# it is preferred to always offer frame pointers as a config
576# option on the architecture (regardless of KERNEL_DEBUG):
577#
578config ARCH_WANT_FRAME_POINTERS
579 bool
580 help
581
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582config FRAME_POINTER
583 bool "Compile the kernel with frame pointers"
David Howellsb920de12008-02-08 04:19:31 -0800584 depends on DEBUG_KERNEL && \
Ingo Molnarda4276b2009-01-07 11:05:10 +0100585 (CRIS || M68K || M68KNOMMU || FRV || UML || S390 || \
586 AVR32 || SUPERH || BLACKFIN || MN10300) || \
587 ARCH_WANT_FRAME_POINTERS
588 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 help
Ingo Molnarda4276b2009-01-07 11:05:10 +0100590 If you say Y here the resulting kernel image will be slightly
591 larger and slower, but it gives very useful debugging information
592 in case of kernel bugs. (precise oopses/stacktraces/warnings)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700594config BOOT_PRINTK_DELAY
595 bool "Delay each boot printk message by N milliseconds"
596 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
597 help
598 This build option allows you to read kernel boot messages
599 by inserting a short delay after each one. The delay is
600 specified in milliseconds on the kernel command line,
601 using "boot_delay=N".
602
603 It is likely that you would also need to use "lpj=M" to preset
604 the "loops per jiffie" value.
605 See a previous boot log for the "lpj" value to use for your
606 system, and then set "lpj=M" before setting "boot_delay=N".
607 NOTE: Using this option may adversely affect SMP systems.
608 I.e., processors other than the first one may not boot up.
609 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
610 what it believes to be lockup conditions.
611
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800612config RCU_TORTURE_TEST
613 tristate "torture tests for RCU"
614 depends on DEBUG_KERNEL
615 default n
616 help
617 This option provides a kernel module that runs torture tests
618 on the RCU infrastructure. The kernel module may be built
619 after the fact on the running kernel to be tested, if desired.
620
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700621 Say Y here if you want RCU torture tests to be built into
622 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800623 Say M if you want the RCU torture tests to build as a module.
624 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700625
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700626config RCU_TORTURE_TEST_RUNNABLE
627 bool "torture tests for RCU runnable by default"
628 depends on RCU_TORTURE_TEST = y
629 default n
630 help
631 This option provides a way to build the RCU torture tests
632 directly into the kernel without them starting up at boot
633 time. You can use /proc/sys/kernel/rcutorture_runnable
634 to manually override this setting. This /proc file is
635 available only when the RCU torture tests have been built
636 into the kernel.
637
638 Say Y here if you want the RCU torture tests to start during
639 boot (you probably don't).
640 Say N here if you want the RCU torture tests to start only
641 after being manually enabled via /proc.
642
Paul E. McKenney2133b5d2008-10-02 16:06:39 -0700643config RCU_CPU_STALL_DETECTOR
Paul E. McKenney67182ae2008-08-10 18:35:38 -0700644 bool "Check for stalled CPUs delaying RCU grace periods"
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100645 depends on CLASSIC_RCU || TREE_RCU
646 default n
647 help
648 This option causes RCU to printk information on which
649 CPUs are delaying the current grace period, but only when
650 the grace period extends for excessive time periods.
651
652 Say Y if you want RCU to perform such checks.
653
654 Say N if you are unsure.
655
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +0100656config KPROBES_SANITY_TEST
657 bool "Kprobes sanity tests"
658 depends on DEBUG_KERNEL
659 depends on KPROBES
660 default n
661 help
662 This option provides for testing basic kprobes functionality on
663 boot. A sample kprobe, jprobe and kretprobe are inserted and
664 verified for functionality.
665
666 Say N if you are unsure.
667
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100668config BACKTRACE_SELF_TEST
669 tristate "Self test for the backtrace code"
670 depends on DEBUG_KERNEL
671 default n
672 help
673 This option provides a kernel module that can be used to test
674 the kernel stack backtrace code. This option is not useful
675 for distributions or general kernels, but only for kernel
676 developers working on architecture code.
677
Vegard Nossumad118c52008-06-27 18:04:48 +0200678 Note that if you want to also test saved backtraces, you will
679 have to enable STACKTRACE as well.
680
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100681 Say N if you are unsure.
682
Tejun Heo870d6652008-08-25 19:47:25 +0900683config DEBUG_BLOCK_EXT_DEVT
684 bool "Force extended block device numbers and spread them"
685 depends on DEBUG_KERNEL
686 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +0200687 default n
Tejun Heo870d6652008-08-25 19:47:25 +0900688 help
Tejun Heo0e11e342008-10-13 10:46:01 +0200689 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
690 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
691 YOU ARE DOING. Distros, please enable this and fix whatever
692 is broken.
693
Tejun Heo870d6652008-08-25 19:47:25 +0900694 Conventionally, block device numbers are allocated from
695 predetermined contiguous area. However, extended block area
696 may introduce non-contiguous block device numbers. This
697 option forces most block device numbers to be allocated from
698 the extended space and spreads them to discover kernel or
699 userland code paths which assume predetermined contiguous
700 device number allocation.
701
Tejun Heo55dc7db2008-09-01 13:44:35 +0200702 Note that turning on this debug option shuffles all the
703 device numbers for all IDE and SCSI devices including libata
704 ones, so root partition specified using device number
705 directly (via rdev or root=MAJ:MIN) won't work anymore.
706 Textual device names (root=/dev/sdXn) will continue to work.
707
Tejun Heo870d6652008-08-25 19:47:25 +0900708 Say N if you are unsure.
709
Ankita Garg8bb31b92006-10-02 02:17:36 -0700710config LKDTM
711 tristate "Linux Kernel Dump Test Tool Module"
Don Mullisbf4735a2006-12-10 02:18:37 -0800712 depends on DEBUG_KERNEL
Ankita Garg8bb31b92006-10-02 02:17:36 -0700713 depends on KPROBES
Chris Snookfddd9cf2008-02-23 15:23:26 -0800714 depends on BLOCK
Ankita Garg8bb31b92006-10-02 02:17:36 -0700715 default n
716 help
717 This module enables testing of the different dumping mechanisms by
718 inducing system failures at predefined crash points.
719 If you don't need it: say N
720 Choose M here to compile this code as a module. The module will be
721 called lkdtm.
722
723 Documentation on how to use the module can be found in
724 drivers/misc/lkdtm.c
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800725
726config FAULT_INJECTION
Andrew Morton1ab85092006-12-08 02:39:49 -0800727 bool "Fault-injection framework"
728 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -0800729 help
730 Provide fault-injection framework.
731 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800732
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800733config FAILSLAB
Andrew Morton1ab85092006-12-08 02:39:49 -0800734 bool "Fault-injection capability for kmalloc"
735 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +0900736 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800737 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800738 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800739
Akinobu Mita933e3122006-12-08 02:39:45 -0800740config FAIL_PAGE_ALLOC
741 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab85092006-12-08 02:39:49 -0800742 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800743 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800744 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800745
Akinobu Mitac17bb492006-12-08 02:39:46 -0800746config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100747 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -0700748 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -0800749 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800750 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800751
Jens Axboe581d4e22008-09-14 05:56:33 -0700752config FAIL_IO_TIMEOUT
753 bool "Faul-injection capability for faking disk interrupts"
754 depends on FAULT_INJECTION && BLOCK
755 help
756 Provide fault-injection capability on end IO handling. This
757 will make the block layer "forget" an interrupt as configured,
758 thus exercising the error handling.
759
760 Only works with drivers that use the generic timeout handling,
761 for others it wont do anything.
762
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800763config FAULT_INJECTION_DEBUG_FS
764 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab85092006-12-08 02:39:49 -0800765 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800766 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800767 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -0800768
769config FAULT_INJECTION_STACKTRACE_FILTER
770 bool "stacktrace filter for fault-injection capabilities"
771 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -0700772 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -0800773 select STACKTRACE
Tony Breeds7563dc62008-09-02 16:50:38 +1000774 select FRAME_POINTER if !PPC
Akinobu Mita1df49002007-02-20 13:57:56 -0800775 help
776 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700777
Arjan van de Ven97455122008-01-25 21:08:34 +0100778config LATENCYTOP
779 bool "Latency measuring infrastructure"
Tony Breeds7563dc62008-09-02 16:50:38 +1000780 select FRAME_POINTER if !MIPS && !PPC
Arjan van de Ven97455122008-01-25 21:08:34 +0100781 select KALLSYMS
782 select KALLSYMS_ALL
783 select STACKTRACE
784 select SCHEDSTATS
785 select SCHED_DEBUG
Heiko Carstensaa7d9352008-02-01 17:45:14 +0100786 depends on HAVE_LATENCYTOP_SUPPORT
Arjan van de Ven97455122008-01-25 21:08:34 +0100787 help
788 Enable this option if you want to use the LatencyTOP tool
789 to find out which userspace is blocking on what kernel operations.
790
Andi Kleen9e94cd32008-08-16 07:53:05 +0200791config SYSCTL_SYSCALL_CHECK
792 bool "Sysctl checks"
793 depends on SYSCTL_SYSCALL
794 ---help---
795 sys_sysctl uses binary paths that have been found challenging
796 to properly maintain and use. This enables checks that help
797 you to keep things correct.
798
Akinobu Mita6a11f752009-03-31 15:23:17 -0700799source mm/Kconfig.debug
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +0200800source kernel/trace/Kconfig
801
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100802config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +0100803 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100804 depends on PCI && X86
805 help
806 If you want to debug problems which hang or crash the kernel early
807 on boot and the crashing machine has a FireWire port, you can use
808 this feature to remotely access the memory of the crashed machine
809 over FireWire. This employs remote DMA as part of the OHCI1394
810 specification which is now the standard for FireWire controllers.
811
812 With remote DMA, you can monitor the printk buffer remotely using
813 firescope and access all memory below 4GB using fireproxy from gdb.
814 Even controlling a kernel debugger is possible using remote DMA.
815
816 Usage:
817
818 If ohci1394_dma=early is used as boot parameter, it will initialize
819 all OHCI1394 controllers which are found in the PCI config space.
820
821 As all changes to the FireWire bus such as enabling and disabling
822 devices cause a bus reset and thereby disable remote DMA for all
823 devices, be sure to have the cable plugged and FireWire enabled on
824 the debugging host before booting the debug target for debugging.
825
826 This code (~1k) is freed after boot. By then, the firewire stack
827 in charge of the OHCI-1394 controllers should be used instead.
828
829 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +0100830
Stefan Richter080de8c2008-02-28 20:54:43 +0100831config FIREWIRE_OHCI_REMOTE_DMA
832 bool "Remote debugging over FireWire with firewire-ohci"
833 depends on FIREWIRE_OHCI
834 help
835 This option lets you use the FireWire bus for remote debugging
836 with help of the firewire-ohci driver. It enables unfiltered
837 remote DMA in firewire-ohci.
838 See Documentation/debugging-via-ohci1394.txt for more information.
839
840 If unsure, say N.
841
Randy Dunlap152de302009-02-20 15:38:47 -0800842config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -0700843 bool "Build targets in Documentation/ tree"
844 depends on HEADERS_CHECK
845 help
846 This option attempts to build objects from the source files in the
847 kernel Documentation/ tree.
848
849 Say N if you are unsure.
850
Jason Barone9d376f2009-02-05 11:51:38 -0500851config DYNAMIC_DEBUG
Jason Baron86151fd2009-02-05 11:53:15 -0500852 bool "Enable dynamic printk() support"
Jason Baron346e15b2008-08-12 16:46:19 -0400853 default n
854 depends on PRINTK
Jason Baron86151fd2009-02-05 11:53:15 -0500855 depends on DEBUG_FS
Jason Baron346e15b2008-08-12 16:46:19 -0400856 select PRINTK_DEBUG
857 help
858
859 Compiles debug level messages into the kernel, which would not
860 otherwise be available at runtime. These messages can then be
Jason Baron86151fd2009-02-05 11:53:15 -0500861 enabled/disabled based on various levels of scope - per source file,
862 function, module, format string, and line number. This mechanism
863 implicitly enables all pr_debug() and dev_dbg() calls. The impact of
864 this compile option is a larger kernel text size of about 2%.
Jason Baron346e15b2008-08-12 16:46:19 -0400865
866 Usage:
867
Jason Baron86151fd2009-02-05 11:53:15 -0500868 Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file,
869 which is contained in the 'debugfs' filesystem. Thus, the debugfs
870 filesystem must first be mounted before making use of this feature.
871 We refer the control file as: <debugfs>/dynamic_debug/ddebug. This
872 file contains a list of the debug statements that can be enabled. The
873 format for each line of the file is:
Jason Baron346e15b2008-08-12 16:46:19 -0400874
Jason Baron86151fd2009-02-05 11:53:15 -0500875 filename:lineno [module]function flags format
Jason Baron346e15b2008-08-12 16:46:19 -0400876
Jason Baron86151fd2009-02-05 11:53:15 -0500877 filename : source file of the debug statement
878 lineno : line number of the debug statement
879 module : module that contains the debug statement
880 function : function that contains the debug statement
881 flags : 'p' means the line is turned 'on' for printing
882 format : the format used for the debug statement
Jason Baron346e15b2008-08-12 16:46:19 -0400883
884 From a live system:
885
Jason Baron86151fd2009-02-05 11:53:15 -0500886 nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
887 # filename:lineno [module]function flags format
888 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
889 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
890 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
Jason Baron346e15b2008-08-12 16:46:19 -0400891
Jason Baron86151fd2009-02-05 11:53:15 -0500892 Example usage:
Jason Baron346e15b2008-08-12 16:46:19 -0400893
Jason Baron86151fd2009-02-05 11:53:15 -0500894 // enable the message at line 1603 of file svcsock.c
895 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
896 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400897
Jason Baron86151fd2009-02-05 11:53:15 -0500898 // enable all the messages in file svcsock.c
899 nullarbor:~ # echo -n 'file svcsock.c +p' >
900 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400901
Jason Baron86151fd2009-02-05 11:53:15 -0500902 // enable all the messages in the NFS server module
903 nullarbor:~ # echo -n 'module nfsd +p' >
904 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400905
Jason Baron86151fd2009-02-05 11:53:15 -0500906 // enable all 12 messages in the function svc_process()
907 nullarbor:~ # echo -n 'func svc_process +p' >
908 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400909
Jason Baron86151fd2009-02-05 11:53:15 -0500910 // disable all 12 messages in the function svc_process()
911 nullarbor:~ # echo -n 'func svc_process -p' >
912 <debugfs>/dynamic_debug/ddebug
Jason Baron346e15b2008-08-12 16:46:19 -0400913
Jason Baron86151fd2009-02-05 11:53:15 -0500914 See Documentation/dynamic-debug-howto.txt for additional information.
Jason Baron346e15b2008-08-12 16:46:19 -0400915
Joerg Roedel5ee00bd2009-01-09 12:14:24 +0100916config DMA_API_DEBUG
917 bool "Enable debugging of DMA-API usage"
918 depends on HAVE_DMA_API_DEBUG
919 help
920 Enable this option to debug the use of the DMA API by device drivers.
921 With this option you will be able to detect common bugs in device
922 drivers like double-freeing of DMA mappings or freeing mappings that
923 were never allocated.
924 This option causes a performance degredation. Use only if you want
925 to debug device drivers. If unsure, say N.
926
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700927source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +0200928
929source "lib/Kconfig.kgdb"