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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
153 mode for more than 10 seconds, without giving other tasks a
154 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 Molnarb642b6d2007-07-09 18:52:00 +0200165config SCHED_DEBUG
166 bool "Collect scheduler debugging info"
167 depends on DEBUG_KERNEL && PROC_FS
168 default y
169 help
170 If you say Y here, the /proc/sched_debug file will be provided
171 that can help debug the scheduler. The runtime overhead of this
172 option is minimal.
173
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174config SCHEDSTATS
175 bool "Collect scheduler statistics"
176 depends on DEBUG_KERNEL && PROC_FS
177 help
178 If you say Y here, additional code will be inserted into the
179 scheduler and related routines to collect statistics about
180 scheduler behavior and provide them in /proc/schedstat. These
181 stats may be useful for both tuning and debugging the scheduler
182 If you aren't debugging the scheduler or trying to tune a specific
183 application, you can say N to avoid the very slight overhead
184 this adds.
185
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800186config TIMER_STATS
187 bool "Collect kernel timers statistics"
188 depends on DEBUG_KERNEL && PROC_FS
189 help
190 If you say Y here, additional code will be inserted into the
191 timer routines to collect statistics about kernel timers being
192 reprogrammed. The statistics can be read from /proc/timer_stats.
193 The statistics collection is started by writing 1 to /proc/timer_stats,
194 writing 0 stops it. This feature is useful to collect information
Ingo Molnarc1a834d2007-06-01 00:47:16 -0700195 about timer usage patterns in kernel and userspace. This feature
196 is lightweight if enabled in the kernel config but not activated
197 (it defaults to deactivated on bootup and will only be activated
198 if some application like powertop activates it explicitly).
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800199
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700200config DEBUG_OBJECTS
201 bool "Debug object operations"
202 depends on DEBUG_KERNEL
203 help
204 If you say Y here, additional code will be inserted into the
205 kernel to track the life time of various objects and validate
206 the operations on those objects.
207
208config DEBUG_OBJECTS_SELFTEST
209 bool "Debug objects selftest"
210 depends on DEBUG_OBJECTS
211 help
212 This enables the selftest of the object debug code.
213
214config DEBUG_OBJECTS_FREE
215 bool "Debug objects in freed memory"
216 depends on DEBUG_OBJECTS
217 help
218 This enables checks whether a k/v free operation frees an area
219 which contains an object which has not been deactivated
220 properly. This can make kmalloc/kfree-intensive workloads
221 much slower.
222
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700223config DEBUG_OBJECTS_TIMERS
224 bool "Debug timer objects"
225 depends on DEBUG_OBJECTS
226 help
227 If you say Y here, additional code will be inserted into the
228 timer routines to track the life time of timer objects and
229 validate the timer operations.
230
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800232 bool "Debug slab memory allocations"
Ingo Molnar50dd26b2006-01-08 01:01:42 -0800233 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 help
235 Say Y here to have the kernel do limited verification on memory
236 allocation as well as poisoning memory on free to catch use of freed
237 memory. This can make kmalloc/kfree-intensive workloads much slower.
238
Al Viro871751e2006-03-25 03:06:39 -0800239config DEBUG_SLAB_LEAK
240 bool "Memory leak debugging"
241 depends on DEBUG_SLAB
242
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700243config SLUB_DEBUG_ON
244 bool "SLUB debugging on by default"
245 depends on SLUB && SLUB_DEBUG
246 default n
247 help
248 Boot with debugging on by default. SLUB boots by default with
249 the runtime debug capabilities switched off. Enabling this is
250 equivalent to specifying the "slub_debug" parameter on boot.
251 There is no support for more fine grained debug control like
252 possible with slub_debug=xxx. SLUB debugging may be switched
253 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
254 "slub_debug=-".
255
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800256config SLUB_STATS
257 default n
258 bool "Enable SLUB performance statistics"
Christoph Lameter5b06c8532008-04-14 18:51:34 +0300259 depends on SLUB && SLUB_DEBUG && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800260 help
261 SLUB statistics are useful to debug SLUBs allocation behavior in
262 order find ways to optimize the allocator. This should never be
263 enabled for production use since keeping statistics slows down
264 the allocator by a few percentage points. The slabinfo command
265 supports the determination of the most active slabs to figure
266 out which slabs are relevant to a particular load.
267 Try running: slabinfo -DA
268
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269config DEBUG_PREEMPT
270 bool "Debug preemptible kernel"
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100271 depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 default y
273 help
274 If you say Y here then the kernel will use a debug variant of the
275 commonly used smp_processor_id() function and will print warnings
276 if kernel code uses it in a preemption-unsafe way. Also, the kernel
277 will detect preemption count underflows.
278
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700279config DEBUG_RT_MUTEXES
280 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700281 depends on DEBUG_KERNEL && RT_MUTEXES
282 help
283 This allows rt mutex semantics violations and rt mutex related
284 deadlocks (lockups) to be detected and reported automatically.
285
286config DEBUG_PI_LIST
287 bool
288 default y
289 depends on DEBUG_RT_MUTEXES
290
Thomas Gleixner61a87122006-06-27 02:54:56 -0700291config RT_MUTEX_TESTER
292 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700293 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700294 help
295 This option enables a rt-mutex tester.
296
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700298 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 depends on DEBUG_KERNEL
300 help
301 Say Y here and build SMP to catch missing spinlock initialization
302 and certain other kinds of spinlock errors commonly made. This is
303 best used in conjunction with the NMI watchdog so that spinlock
304 deadlocks are also debuggable.
305
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700306config DEBUG_MUTEXES
307 bool "Mutex debugging: basic checks"
308 depends on DEBUG_KERNEL
309 help
310 This feature allows mutex semantics violations to be detected and
311 reported.
312
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700313config DEBUG_LOCK_ALLOC
314 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700315 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700316 select DEBUG_SPINLOCK
317 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700318 select LOCKDEP
319 help
320 This feature will check whether any held lock (spinlock, rwlock,
321 mutex or rwsem) is incorrectly freed by the kernel, via any of the
322 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
323 vfree(), etc.), whether a live lock is incorrectly reinitialized via
324 spin_lock_init()/mutex_init()/etc., or whether there is any lock
325 held during task exit.
326
327config PROVE_LOCKING
328 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700329 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700330 select LOCKDEP
331 select DEBUG_SPINLOCK
332 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700333 select DEBUG_LOCK_ALLOC
334 default n
335 help
336 This feature enables the kernel to prove that all locking
337 that occurs in the kernel runtime is mathematically
338 correct: that under no circumstance could an arbitrary (and
339 not yet triggered) combination of observed locking
340 sequences (on an arbitrary number of CPUs, running an
341 arbitrary number of tasks and interrupt contexts) cause a
342 deadlock.
343
344 In short, this feature enables the kernel to report locking
345 related deadlocks before they actually occur.
346
347 The proof does not depend on how hard and complex a
348 deadlock scenario would be to trigger: how many
349 participant CPUs, tasks and irq-contexts would be needed
350 for it to trigger. The proof also does not depend on
351 timing: if a race and a resulting deadlock is possible
352 theoretically (no matter how unlikely the race scenario
353 is), it will be proven so and will immediately be
354 reported by the kernel (once the event is observed that
355 makes the deadlock theoretically possible).
356
357 If a deadlock is impossible (i.e. the locking rules, as
358 observed by the kernel, are mathematically correct), the
359 kernel reports nothing.
360
361 NOTE: this feature can also be enabled for rwlocks, mutexes
362 and rwsems - in which case all dependencies between these
363 different locking variants are observed and mapped too, and
364 the proof of observed correctness is also maintained for an
365 arbitrary combination of these separate locking variants.
366
367 For more details, see Documentation/lockdep-design.txt.
368
369config LOCKDEP
370 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700371 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700372 select STACKTRACE
Franck Bui-Huu14cf2322007-04-26 00:20:15 -0700373 select FRAME_POINTER if !X86 && !MIPS
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700374 select KALLSYMS
375 select KALLSYMS_ALL
376
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700377config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700378 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700379 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
380 select LOCKDEP
381 select DEBUG_SPINLOCK
382 select DEBUG_MUTEXES
383 select DEBUG_LOCK_ALLOC
384 default n
385 help
386 This feature enables tracking lock contention points
387
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700388 For more details, see Documentation/lockstat.txt
389
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700390config DEBUG_LOCKDEP
391 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700392 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700393 help
394 If you say Y here, the lock dependency engine will do
395 additional runtime checks to debug itself, at the price
396 of more runtime overhead.
397
398config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700399 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700400 bool
401 default y
402 depends on TRACE_IRQFLAGS_SUPPORT
403 depends on PROVE_LOCKING
404
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700406 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407 depends on DEBUG_KERNEL
408 help
409 If you say Y here, various routines which may sleep will become very
410 noisy if they are called with a spinlock held.
411
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700412config DEBUG_LOCKING_API_SELFTESTS
413 bool "Locking API boot-time self-tests"
414 depends on DEBUG_KERNEL
415 help
416 Say Y here if you want the kernel to run a short self-test during
417 bootup. The self-test checks whether common types of locking bugs
418 are detected by debugging mechanisms or not. (if you disable
419 lock debugging then those bugs wont be detected of course.)
420 The following locking APIs are covered: spinlocks, rwlocks,
421 mutexes and rwsems.
422
Ingo Molnar8637c092006-07-03 00:24:38 -0700423config STACKTRACE
424 bool
425 depends on STACKTRACE_SUPPORT
426
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427config DEBUG_KOBJECT
428 bool "kobject debugging"
429 depends on DEBUG_KERNEL
430 help
431 If you say Y here, some extra kobject debugging messages will be sent
432 to the syslog.
433
434config DEBUG_HIGHMEM
435 bool "Highmem debugging"
436 depends on DEBUG_KERNEL && HIGHMEM
437 help
438 This options enables addition error checking for high memory systems.
439 Disable for production systems.
440
441config DEBUG_BUGVERBOSE
442 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700443 depends on BUG
David Howellsb920de12008-02-08 04:19:31 -0800444 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
445 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446 default !EMBEDDED
447 help
448 Say Y here to make BUG() panics output the file name and line number
449 of the BUG call as well as the EIP and oops trace. This aids
450 debugging but costs about 70-100K of memory.
451
452config DEBUG_INFO
453 bool "Compile the kernel with debug info"
454 depends on DEBUG_KERNEL
455 help
456 If you say Y here the resulting kernel image will include
457 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600458 This adds debug symbols to the kernel and modules (gcc -g), and
459 is needed if you intend to use kernel crashdump or binary object
460 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 Say Y here only if you plan to debug the kernel.
462
463 If unsure, say N.
464
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800465config DEBUG_VM
466 bool "Debug VM"
467 depends on DEBUG_KERNEL
468 help
Nick Piggin13e74442006-01-06 00:10:58 -0800469 Enable this to turn on extended checks in the virtual-memory system
470 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800471
472 If unsure, say N.
473
Dave Hansenad775f52008-02-15 14:38:01 -0800474config DEBUG_WRITECOUNT
475 bool "Debug filesystem writers count"
476 depends on DEBUG_KERNEL
477 help
478 Enable this to catch wrong use of the writers count in struct
479 vfsmount. This will increase the size of each file struct by
480 32 bits.
481
482 If unsure, say N.
483
Dave Jones199a9af2006-09-29 01:59:00 -0700484config DEBUG_LIST
485 bool "Debug linked list manipulation"
486 depends on DEBUG_KERNEL
487 help
488 Enable this to turn on extended checks in the linked-list
489 walking routines.
490
491 If unsure, say N.
492
Jens Axboed6ec0842007-10-22 20:01:06 +0200493config DEBUG_SG
494 bool "Debug SG table operations"
495 depends on DEBUG_KERNEL
496 help
497 Enable this to turn on checks on scatter-gather tables. This can
498 help find problems with drivers that do not properly initialize
499 their sg tables.
500
501 If unsure, say N.
502
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503config FRAME_POINTER
504 bool "Compile the kernel with frame pointers"
David Howellsb920de12008-02-08 04:19:31 -0800505 depends on DEBUG_KERNEL && \
506 (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390 || \
507 AVR32 || SUPERH || BLACKFIN || MN10300)
Paolo 'Blaisorblade' Giarrusso37fce852005-05-28 15:51:59 -0700508 default y if DEBUG_INFO && UML
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 help
510 If you say Y here the resulting kernel image will be slightly larger
Jesper Juhl2a38bcc2005-10-30 15:02:51 -0800511 and slower, but it might give very useful debugging information on
512 some architectures or if you use external debuggers.
Andi Kleenaeb39982005-09-12 18:49:25 +0200513 If you don't debug the kernel, you can say N.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514
Randy Dunlapbfe8df32007-10-16 01:23:46 -0700515config BOOT_PRINTK_DELAY
516 bool "Delay each boot printk message by N milliseconds"
517 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
518 help
519 This build option allows you to read kernel boot messages
520 by inserting a short delay after each one. The delay is
521 specified in milliseconds on the kernel command line,
522 using "boot_delay=N".
523
524 It is likely that you would also need to use "lpj=M" to preset
525 the "loops per jiffie" value.
526 See a previous boot log for the "lpj" value to use for your
527 system, and then set "lpj=M" before setting "boot_delay=N".
528 NOTE: Using this option may adversely affect SMP systems.
529 I.e., processors other than the first one may not boot up.
530 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
531 what it believes to be lockup conditions.
532
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800533config RCU_TORTURE_TEST
534 tristate "torture tests for RCU"
535 depends on DEBUG_KERNEL
536 default n
537 help
538 This option provides a kernel module that runs torture tests
539 on the RCU infrastructure. The kernel module may be built
540 after the fact on the running kernel to be tested, if desired.
541
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700542 Say Y here if you want RCU torture tests to be built into
543 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800544 Say M if you want the RCU torture tests to build as a module.
545 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700546
Paul E. McKenney31a72bc2008-06-18 09:26:49 -0700547config RCU_TORTURE_TEST_RUNNABLE
548 bool "torture tests for RCU runnable by default"
549 depends on RCU_TORTURE_TEST = y
550 default n
551 help
552 This option provides a way to build the RCU torture tests
553 directly into the kernel without them starting up at boot
554 time. You can use /proc/sys/kernel/rcutorture_runnable
555 to manually override this setting. This /proc file is
556 available only when the RCU torture tests have been built
557 into the kernel.
558
559 Say Y here if you want the RCU torture tests to start during
560 boot (you probably don't).
561 Say N here if you want the RCU torture tests to start only
562 after being manually enabled via /proc.
563
Ananth N Mavinakayanahalli8c1c9352008-01-30 13:32:53 +0100564config KPROBES_SANITY_TEST
565 bool "Kprobes sanity tests"
566 depends on DEBUG_KERNEL
567 depends on KPROBES
568 default n
569 help
570 This option provides for testing basic kprobes functionality on
571 boot. A sample kprobe, jprobe and kretprobe are inserted and
572 verified for functionality.
573
574 Say N if you are unsure.
575
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100576config BACKTRACE_SELF_TEST
577 tristate "Self test for the backtrace code"
578 depends on DEBUG_KERNEL
579 default n
580 help
581 This option provides a kernel module that can be used to test
582 the kernel stack backtrace code. This option is not useful
583 for distributions or general kernels, but only for kernel
584 developers working on architecture code.
585
Vegard Nossumad118c52008-06-27 18:04:48 +0200586 Note that if you want to also test saved backtraces, you will
587 have to enable STACKTRACE as well.
588
Arjan van de Ven6dab2772008-01-30 13:33:08 +0100589 Say N if you are unsure.
590
Ankita Garg8bb31b92006-10-02 02:17:36 -0700591config LKDTM
592 tristate "Linux Kernel Dump Test Tool Module"
Don Mullisbf4735a2006-12-10 02:18:37 -0800593 depends on DEBUG_KERNEL
Ankita Garg8bb31b92006-10-02 02:17:36 -0700594 depends on KPROBES
Chris Snookfddd9cf2008-02-23 15:23:26 -0800595 depends on BLOCK
Ankita Garg8bb31b92006-10-02 02:17:36 -0700596 default n
597 help
598 This module enables testing of the different dumping mechanisms by
599 inducing system failures at predefined crash points.
600 If you don't need it: say N
601 Choose M here to compile this code as a module. The module will be
602 called lkdtm.
603
604 Documentation on how to use the module can be found in
605 drivers/misc/lkdtm.c
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800606
607config FAULT_INJECTION
Andrew Morton1ab85092006-12-08 02:39:49 -0800608 bool "Fault-injection framework"
609 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -0800610 help
611 Provide fault-injection framework.
612 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800613
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800614config FAILSLAB
Andrew Morton1ab85092006-12-08 02:39:49 -0800615 bool "Fault-injection capability for kmalloc"
616 depends on FAULT_INJECTION
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800617 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800618 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800619
Akinobu Mita933e3122006-12-08 02:39:45 -0800620config FAIL_PAGE_ALLOC
621 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab85092006-12-08 02:39:49 -0800622 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800623 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800624 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800625
Akinobu Mitac17bb492006-12-08 02:39:46 -0800626config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100627 bool "Fault-injection capability for disk IO"
Andrew Morton1ab85092006-12-08 02:39:49 -0800628 depends on FAULT_INJECTION
Akinobu Mitac17bb492006-12-08 02:39:46 -0800629 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800630 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800631
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800632config FAULT_INJECTION_DEBUG_FS
633 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab85092006-12-08 02:39:49 -0800634 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800635 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800636 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -0800637
638config FAULT_INJECTION_STACKTRACE_FILTER
639 bool "stacktrace filter for fault-injection capabilities"
640 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -0700641 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -0800642 select STACKTRACE
643 select FRAME_POINTER
644 help
645 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700646
Arjan van de Ven97455122008-01-25 21:08:34 +0100647config LATENCYTOP
648 bool "Latency measuring infrastructure"
649 select FRAME_POINTER if !MIPS
650 select KALLSYMS
651 select KALLSYMS_ALL
652 select STACKTRACE
653 select SCHEDSTATS
654 select SCHED_DEBUG
Heiko Carstensaa7d9352008-02-01 17:45:14 +0100655 depends on HAVE_LATENCYTOP_SUPPORT
Arjan van de Ven97455122008-01-25 21:08:34 +0100656 help
657 Enable this option if you want to use the LatencyTOP tool
658 to find out which userspace is blocking on what kernel operations.
659
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +0200660source kernel/trace/Kconfig
661
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100662config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +0100663 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +0100664 depends on PCI && X86
665 help
666 If you want to debug problems which hang or crash the kernel early
667 on boot and the crashing machine has a FireWire port, you can use
668 this feature to remotely access the memory of the crashed machine
669 over FireWire. This employs remote DMA as part of the OHCI1394
670 specification which is now the standard for FireWire controllers.
671
672 With remote DMA, you can monitor the printk buffer remotely using
673 firescope and access all memory below 4GB using fireproxy from gdb.
674 Even controlling a kernel debugger is possible using remote DMA.
675
676 Usage:
677
678 If ohci1394_dma=early is used as boot parameter, it will initialize
679 all OHCI1394 controllers which are found in the PCI config space.
680
681 As all changes to the FireWire bus such as enabling and disabling
682 devices cause a bus reset and thereby disable remote DMA for all
683 devices, be sure to have the cable plugged and FireWire enabled on
684 the debugging host before booting the debug target for debugging.
685
686 This code (~1k) is freed after boot. By then, the firewire stack
687 in charge of the OHCI-1394 controllers should be used instead.
688
689 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +0100690
Stefan Richter080de8c2008-02-28 20:54:43 +0100691config FIREWIRE_OHCI_REMOTE_DMA
692 bool "Remote debugging over FireWire with firewire-ohci"
693 depends on FIREWIRE_OHCI
694 help
695 This option lets you use the FireWire bus for remote debugging
696 with help of the firewire-ohci driver. It enables unfiltered
697 remote DMA in firewire-ohci.
698 See Documentation/debugging-via-ohci1394.txt for more information.
699
700 If unsure, say N.
701
Mathieu Desnoyers267c4022007-10-18 23:41:07 -0700702source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +0200703
704source "lib/Kconfig.kgdb"