blob: 4448f91b865c10a48933a6a8d1c4ea645266b90c [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
Andrew Mortoncebc04b2006-08-14 22:43:18 -070012config ENABLE_MUST_CHECK
13 bool "Enable __must_check logic"
14 default y
15 help
16 Enable the __must_check logic in the kernel build. Disable this to
17 suppress the "warning: ignoring return value of 'foo', declared with
18 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -070019
Linus Torvalds1da177e2005-04-16 15:20:36 -070020config MAGIC_SYSRQ
21 bool "Magic SysRq key"
Adrian Bunkf346f4b2006-01-09 20:54:51 -080022 depends on !UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070023 help
24 If you say Y here, you will have some control over the system even
25 if the system crashes for example during kernel debugging (e.g., you
26 will be able to flush the buffer cache to disk, reboot the system
27 immediately or dump some status information). This is accomplished
28 by pressing various keys while holding SysRq (Alt+PrintScreen). It
29 also works on a serial console (on PC hardware at least), if you
30 send a BREAK and then within 5 seconds a command keypress. The
31 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
32 unless you really know what this hack does.
33
Arjan van de Venf71d20e2006-06-28 04:26:45 -070034config UNUSED_SYMBOLS
35 bool "Enable unused/obsolete exported symbols"
36 default y if X86
37 help
38 Unused but exported symbols make the kernel needlessly bigger. For
39 that reason most of these unused exports will soon be removed. This
40 option is provided temporarily to provide a transition period in case
41 some external kernel module needs one of these symbols anyway. If you
42 encounter such a case in your module, consider if you are actually
43 using the right API. (rationale: since nobody in the kernel is using
44 this in a module, there is a pretty good chance it's actually the
45 wrong interface to use). If you really need the symbol, please send a
46 mail to the linux kernel mailing list mentioning the symbol and why
47 you really need it, and what the merge plan to the mainline kernel for
48 your module is.
49
Don Mullisbf4735a2006-12-10 02:18:37 -080050config DEBUG_FS
51 bool "Debug Filesystem"
52 depends on SYSFS
53 help
54 debugfs is a virtual file system that kernel developers use to put
55 debugging files into. Enable this option to be able to read and
56 write to these files.
57
58 If unsure, say N.
59
60config HEADERS_CHECK
61 bool "Run 'make headers_check' when building vmlinux"
62 depends on !UML
63 help
64 This option will extract the user-visible kernel headers whenever
65 building the kernel, and will run basic sanity checks on them to
66 ensure that exported files do not attempt to include files which
67 were not exported, etc.
68
69 If you're making modifications to header files which are
70 relevant for userspace, say 'Y', and check the headers
71 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
72 your build tree), to make sure they're suitable.
73
Adrian Bunkf346f4b2006-01-09 20:54:51 -080074config DEBUG_KERNEL
75 bool "Kernel debugging"
76 help
77 Say Y here if you are developing drivers or trying to debug and
78 identify kernel problems.
79
David Woodhousea304e1b2007-02-12 00:52:00 -080080config DEBUG_SHIRQ
81 bool "Debug shared IRQ handlers"
82 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
83 help
84 Enable this to generate a spurious interrupt as soon as a shared
85 interrupt handler is registered, and just before one is deregistered.
86 Drivers ought to be able to handle interrupts coming in at those
87 points; some don't and need to be caught.
88
Linus Torvalds1da177e2005-04-16 15:20:36 -070089config LOG_BUF_SHIFT
90 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
91 range 12 21
Ingo Molnarfbb9ce952006-07-03 00:24:50 -070092 default 17 if S390 || LOCKDEP
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 default 16 if X86_NUMAQ || IA64
94 default 15 if SMP
95 default 14
96 help
97 Select kernel log buffer size as a power of 2.
98 Defaults and Examples:
99 17 => 128 KB for S/390
100 16 => 64 KB for x86 NUMAQ or IA-64
101 15 => 32 KB for SMP
102 14 => 16 KB for uniprocessor
103 13 => 8 KB
104 12 => 4 KB
105
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700106config DETECT_SOFTLOCKUP
107 bool "Detect Soft Lockups"
Heiko Carstensdea20a32006-10-11 01:20:44 -0700108 depends on DEBUG_KERNEL && !S390
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700109 default y
110 help
111 Say Y here to enable the kernel to detect "soft lockups",
112 which are bugs that cause the kernel to loop in kernel
113 mode for more than 10 seconds, without giving other tasks a
114 chance to run.
115
116 When a soft-lockup is detected, the kernel will print the
117 current stack trace (which you should report), but the
118 system will stay locked up. This feature has negligible
119 overhead.
120
121 (Note that "hard lockups" are separate type of bugs that
122 can be detected via the NMI-watchdog, on platforms that
123 support it.)
124
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125config SCHEDSTATS
126 bool "Collect scheduler statistics"
127 depends on DEBUG_KERNEL && PROC_FS
128 help
129 If you say Y here, additional code will be inserted into the
130 scheduler and related routines to collect statistics about
131 scheduler behavior and provide them in /proc/schedstat. These
132 stats may be useful for both tuning and debugging the scheduler
133 If you aren't debugging the scheduler or trying to tune a specific
134 application, you can say N to avoid the very slight overhead
135 this adds.
136
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800137config TIMER_STATS
138 bool "Collect kernel timers statistics"
139 depends on DEBUG_KERNEL && PROC_FS
140 help
141 If you say Y here, additional code will be inserted into the
142 timer routines to collect statistics about kernel timers being
143 reprogrammed. The statistics can be read from /proc/timer_stats.
144 The statistics collection is started by writing 1 to /proc/timer_stats,
145 writing 0 stops it. This feature is useful to collect information
146 about timer usage patterns in kernel and userspace.
147
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800149 bool "Debug slab memory allocations"
Ingo Molnar50dd26ba2006-01-08 01:01:42 -0800150 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 help
152 Say Y here to have the kernel do limited verification on memory
153 allocation as well as poisoning memory on free to catch use of freed
154 memory. This can make kmalloc/kfree-intensive workloads much slower.
155
Al Viro871751e2006-03-25 03:06:39 -0800156config DEBUG_SLAB_LEAK
157 bool "Memory leak debugging"
158 depends on DEBUG_SLAB
159
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160config DEBUG_PREEMPT
161 bool "Debug preemptible kernel"
Ingo Molnar8637c092006-07-03 00:24:38 -0700162 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 default y
164 help
165 If you say Y here then the kernel will use a debug variant of the
166 commonly used smp_processor_id() function and will print warnings
167 if kernel code uses it in a preemption-unsafe way. Also, the kernel
168 will detect preemption count underflows.
169
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700170config DEBUG_RT_MUTEXES
171 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700172 depends on DEBUG_KERNEL && RT_MUTEXES
173 help
174 This allows rt mutex semantics violations and rt mutex related
175 deadlocks (lockups) to be detected and reported automatically.
176
177config DEBUG_PI_LIST
178 bool
179 default y
180 depends on DEBUG_RT_MUTEXES
181
Thomas Gleixner61a87122006-06-27 02:54:56 -0700182config RT_MUTEX_TESTER
183 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700184 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700185 help
186 This option enables a rt-mutex tester.
187
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700189 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 depends on DEBUG_KERNEL
191 help
192 Say Y here and build SMP to catch missing spinlock initialization
193 and certain other kinds of spinlock errors commonly made. This is
194 best used in conjunction with the NMI watchdog so that spinlock
195 deadlocks are also debuggable.
196
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700197config DEBUG_MUTEXES
198 bool "Mutex debugging: basic checks"
199 depends on DEBUG_KERNEL
200 help
201 This feature allows mutex semantics violations to be detected and
202 reported.
203
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700204config DEBUG_LOCK_ALLOC
205 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700206 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700207 select DEBUG_SPINLOCK
208 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700209 select LOCKDEP
210 help
211 This feature will check whether any held lock (spinlock, rwlock,
212 mutex or rwsem) is incorrectly freed by the kernel, via any of the
213 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
214 vfree(), etc.), whether a live lock is incorrectly reinitialized via
215 spin_lock_init()/mutex_init()/etc., or whether there is any lock
216 held during task exit.
217
218config PROVE_LOCKING
219 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700220 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700221 select LOCKDEP
222 select DEBUG_SPINLOCK
223 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700224 select DEBUG_LOCK_ALLOC
225 default n
226 help
227 This feature enables the kernel to prove that all locking
228 that occurs in the kernel runtime is mathematically
229 correct: that under no circumstance could an arbitrary (and
230 not yet triggered) combination of observed locking
231 sequences (on an arbitrary number of CPUs, running an
232 arbitrary number of tasks and interrupt contexts) cause a
233 deadlock.
234
235 In short, this feature enables the kernel to report locking
236 related deadlocks before they actually occur.
237
238 The proof does not depend on how hard and complex a
239 deadlock scenario would be to trigger: how many
240 participant CPUs, tasks and irq-contexts would be needed
241 for it to trigger. The proof also does not depend on
242 timing: if a race and a resulting deadlock is possible
243 theoretically (no matter how unlikely the race scenario
244 is), it will be proven so and will immediately be
245 reported by the kernel (once the event is observed that
246 makes the deadlock theoretically possible).
247
248 If a deadlock is impossible (i.e. the locking rules, as
249 observed by the kernel, are mathematically correct), the
250 kernel reports nothing.
251
252 NOTE: this feature can also be enabled for rwlocks, mutexes
253 and rwsems - in which case all dependencies between these
254 different locking variants are observed and mapped too, and
255 the proof of observed correctness is also maintained for an
256 arbitrary combination of these separate locking variants.
257
258 For more details, see Documentation/lockdep-design.txt.
259
260config LOCKDEP
261 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700262 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700263 select STACKTRACE
Andi Kleen3b8d1fe2006-09-26 10:52:34 +0200264 select FRAME_POINTER if !X86
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700265 select KALLSYMS
266 select KALLSYMS_ALL
267
268config DEBUG_LOCKDEP
269 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700270 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700271 help
272 If you say Y here, the lock dependency engine will do
273 additional runtime checks to debug itself, at the price
274 of more runtime overhead.
275
276config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700277 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700278 bool
279 default y
280 depends on TRACE_IRQFLAGS_SUPPORT
281 depends on PROVE_LOCKING
282
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700284 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 depends on DEBUG_KERNEL
286 help
287 If you say Y here, various routines which may sleep will become very
288 noisy if they are called with a spinlock held.
289
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700290config DEBUG_LOCKING_API_SELFTESTS
291 bool "Locking API boot-time self-tests"
292 depends on DEBUG_KERNEL
293 help
294 Say Y here if you want the kernel to run a short self-test during
295 bootup. The self-test checks whether common types of locking bugs
296 are detected by debugging mechanisms or not. (if you disable
297 lock debugging then those bugs wont be detected of course.)
298 The following locking APIs are covered: spinlocks, rwlocks,
299 mutexes and rwsems.
300
Ingo Molnar8637c092006-07-03 00:24:38 -0700301config STACKTRACE
302 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700303 depends on DEBUG_KERNEL
Ingo Molnar8637c092006-07-03 00:24:38 -0700304 depends on STACKTRACE_SUPPORT
305
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306config DEBUG_KOBJECT
307 bool "kobject debugging"
308 depends on DEBUG_KERNEL
309 help
310 If you say Y here, some extra kobject debugging messages will be sent
311 to the syslog.
312
313config DEBUG_HIGHMEM
314 bool "Highmem debugging"
315 depends on DEBUG_KERNEL && HIGHMEM
316 help
317 This options enables addition error checking for high memory systems.
318 Disable for production systems.
319
320config DEBUG_BUGVERBOSE
321 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700322 depends on BUG
Jeremy Fitzhardinge91768d62006-12-08 02:36:21 -0800323 depends on ARM || ARM26 || AVR32 || M32R || M68K || SPARC32 || SPARC64 || FRV || SUPERH || GENERIC_BUG
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 default !EMBEDDED
325 help
326 Say Y here to make BUG() panics output the file name and line number
327 of the BUG call as well as the EIP and oops trace. This aids
328 debugging but costs about 70-100K of memory.
329
330config DEBUG_INFO
331 bool "Compile the kernel with debug info"
332 depends on DEBUG_KERNEL
333 help
334 If you say Y here the resulting kernel image will include
335 debugging info resulting in a larger kernel image.
336 Say Y here only if you plan to debug the kernel.
337
338 If unsure, say N.
339
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800340config DEBUG_VM
341 bool "Debug VM"
342 depends on DEBUG_KERNEL
343 help
Nick Piggin13e74442006-01-06 00:10:58 -0800344 Enable this to turn on extended checks in the virtual-memory system
345 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800346
347 If unsure, say N.
348
Dave Jones199a9af2006-09-29 01:59:00 -0700349config DEBUG_LIST
350 bool "Debug linked list manipulation"
351 depends on DEBUG_KERNEL
352 help
353 Enable this to turn on extended checks in the linked-list
354 walking routines.
355
356 If unsure, say N.
357
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358config FRAME_POINTER
359 bool "Compile the kernel with frame pointers"
Paul Mundt2549b322006-09-27 16:22:33 +0900360 depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390 || AVR32 || SUPERH)
Paolo 'Blaisorblade' Giarrusso37fce852005-05-28 15:51:59 -0700361 default y if DEBUG_INFO && UML
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 help
363 If you say Y here the resulting kernel image will be slightly larger
Jesper Juhl2a38bcc2005-10-30 15:02:51 -0800364 and slower, but it might give very useful debugging information on
365 some architectures or if you use external debuggers.
Andi Kleenaeb39982005-09-12 18:49:25 +0200366 If you don't debug the kernel, you can say N.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367
Ingo Molnara9df3d02006-01-14 13:21:33 -0800368config FORCED_INLINING
369 bool "Force gcc to inline functions marked 'inline'"
370 depends on DEBUG_KERNEL
371 default y
372 help
373 This option determines if the kernel forces gcc to inline the functions
374 developers have marked 'inline'. Doing so takes away freedom from gcc to
375 do what it thinks is best, which is desirable for the gcc 3.x series of
376 compilers. The gcc 4.x series have a rewritten inlining algorithm and
377 disabling this option will generate a smaller kernel there. Hopefully
378 this algorithm is so good that allowing gcc4 to make the decision can
379 become the default in the future, until then this option is there to
380 test gcc for this.
381
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800382config RCU_TORTURE_TEST
383 tristate "torture tests for RCU"
384 depends on DEBUG_KERNEL
385 default n
386 help
387 This option provides a kernel module that runs torture tests
388 on the RCU infrastructure. The kernel module may be built
389 after the fact on the running kernel to be tested, if desired.
390
391 Say Y here if you want RCU torture tests to start automatically
392 at boot time (you probably don't).
393 Say M if you want the RCU torture tests to build as a module.
394 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700395
396config LKDTM
397 tristate "Linux Kernel Dump Test Tool Module"
Don Mullisbf4735a2006-12-10 02:18:37 -0800398 depends on DEBUG_KERNEL
Ankita Garg8bb31b92006-10-02 02:17:36 -0700399 depends on KPROBES
400 default n
401 help
402 This module enables testing of the different dumping mechanisms by
403 inducing system failures at predefined crash points.
404 If you don't need it: say N
405 Choose M here to compile this code as a module. The module will be
406 called lkdtm.
407
408 Documentation on how to use the module can be found in
409 drivers/misc/lkdtm.c
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800410
411config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800412 bool "Fault-injection framework"
413 depends on DEBUG_KERNEL
Andrew Morton83ba2542006-12-08 02:39:49 -0800414 depends on STACKTRACE
Akinobu Mita329409a2006-12-08 02:39:48 -0800415 select FRAME_POINTER
416 help
417 Provide fault-injection framework.
418 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800419
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800420config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800421 bool "Fault-injection capability for kmalloc"
422 depends on FAULT_INJECTION
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800423 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800424 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800425
Akinobu Mita933e3122006-12-08 02:39:45 -0800426config FAIL_PAGE_ALLOC
427 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800428 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800429 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800430 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800431
Akinobu Mitac17bb492006-12-08 02:39:46 -0800432config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100433 bool "Fault-injection capability for disk IO"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800434 depends on FAULT_INJECTION
Akinobu Mitac17bb492006-12-08 02:39:46 -0800435 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800436 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800437
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800438config FAULT_INJECTION_DEBUG_FS
439 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800440 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800441 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800442 Enable configuration of fault-injection capabilities via debugfs.