blob: da95e10cfd7094e8996ab08bb38c1f1bd5d4d6f9 [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
Ingo Molnar8446f1d2005-09-06 15:16:27 -070089config DETECT_SOFTLOCKUP
90 bool "Detect Soft Lockups"
Heiko Carstensdea20a32006-10-11 01:20:44 -070091 depends on DEBUG_KERNEL && !S390
Ingo Molnar8446f1d2005-09-06 15:16:27 -070092 default y
93 help
94 Say Y here to enable the kernel to detect "soft lockups",
95 which are bugs that cause the kernel to loop in kernel
96 mode for more than 10 seconds, without giving other tasks a
97 chance to run.
98
99 When a soft-lockup is detected, the kernel will print the
100 current stack trace (which you should report), but the
101 system will stay locked up. This feature has negligible
102 overhead.
103
104 (Note that "hard lockups" are separate type of bugs that
105 can be detected via the NMI-watchdog, on platforms that
106 support it.)
107
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108config SCHEDSTATS
109 bool "Collect scheduler statistics"
110 depends on DEBUG_KERNEL && PROC_FS
111 help
112 If you say Y here, additional code will be inserted into the
113 scheduler and related routines to collect statistics about
114 scheduler behavior and provide them in /proc/schedstat. These
115 stats may be useful for both tuning and debugging the scheduler
116 If you aren't debugging the scheduler or trying to tune a specific
117 application, you can say N to avoid the very slight overhead
118 this adds.
119
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800120config TIMER_STATS
121 bool "Collect kernel timers statistics"
122 depends on DEBUG_KERNEL && PROC_FS
123 help
124 If you say Y here, additional code will be inserted into the
125 timer routines to collect statistics about kernel timers being
126 reprogrammed. The statistics can be read from /proc/timer_stats.
127 The statistics collection is started by writing 1 to /proc/timer_stats,
128 writing 0 stops it. This feature is useful to collect information
Ingo Molnarc1a834d2007-06-01 00:47:16 -0700129 about timer usage patterns in kernel and userspace. This feature
130 is lightweight if enabled in the kernel config but not activated
131 (it defaults to deactivated on bootup and will only be activated
132 if some application like powertop activates it explicitly).
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800133
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800135 bool "Debug slab memory allocations"
Ingo Molnar50dd26ba2006-01-08 01:01:42 -0800136 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 help
138 Say Y here to have the kernel do limited verification on memory
139 allocation as well as poisoning memory on free to catch use of freed
140 memory. This can make kmalloc/kfree-intensive workloads much slower.
141
Al Viro871751e2006-03-25 03:06:39 -0800142config DEBUG_SLAB_LEAK
143 bool "Memory leak debugging"
144 depends on DEBUG_SLAB
145
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146config DEBUG_PREEMPT
147 bool "Debug preemptible kernel"
Ingo Molnar8637c092006-07-03 00:24:38 -0700148 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 default y
150 help
151 If you say Y here then the kernel will use a debug variant of the
152 commonly used smp_processor_id() function and will print warnings
153 if kernel code uses it in a preemption-unsafe way. Also, the kernel
154 will detect preemption count underflows.
155
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700156config DEBUG_RT_MUTEXES
157 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700158 depends on DEBUG_KERNEL && RT_MUTEXES
159 help
160 This allows rt mutex semantics violations and rt mutex related
161 deadlocks (lockups) to be detected and reported automatically.
162
163config DEBUG_PI_LIST
164 bool
165 default y
166 depends on DEBUG_RT_MUTEXES
167
Thomas Gleixner61a87122006-06-27 02:54:56 -0700168config RT_MUTEX_TESTER
169 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700170 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700171 help
172 This option enables a rt-mutex tester.
173
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700175 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 depends on DEBUG_KERNEL
177 help
178 Say Y here and build SMP to catch missing spinlock initialization
179 and certain other kinds of spinlock errors commonly made. This is
180 best used in conjunction with the NMI watchdog so that spinlock
181 deadlocks are also debuggable.
182
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700183config DEBUG_MUTEXES
184 bool "Mutex debugging: basic checks"
185 depends on DEBUG_KERNEL
186 help
187 This feature allows mutex semantics violations to be detected and
188 reported.
189
Robert P. J. Dayc761c842007-05-08 00:25:02 -0700190config DEBUG_SEMAPHORE
191 bool "Semaphore debugging"
192 depends on DEBUG_KERNEL
193 depends on ALPHA || FRV
194 default n
195 help
196 If you say Y here then semaphore processing will issue lots of
197 verbose debugging messages. If you suspect a semaphore problem or a
198 kernel hacker asks for this option then say Y. Otherwise say N.
199
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700200config DEBUG_LOCK_ALLOC
201 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700202 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700203 select DEBUG_SPINLOCK
204 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700205 select LOCKDEP
206 help
207 This feature will check whether any held lock (spinlock, rwlock,
208 mutex or rwsem) is incorrectly freed by the kernel, via any of the
209 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
210 vfree(), etc.), whether a live lock is incorrectly reinitialized via
211 spin_lock_init()/mutex_init()/etc., or whether there is any lock
212 held during task exit.
213
214config PROVE_LOCKING
215 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700216 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700217 select LOCKDEP
218 select DEBUG_SPINLOCK
219 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700220 select DEBUG_LOCK_ALLOC
221 default n
222 help
223 This feature enables the kernel to prove that all locking
224 that occurs in the kernel runtime is mathematically
225 correct: that under no circumstance could an arbitrary (and
226 not yet triggered) combination of observed locking
227 sequences (on an arbitrary number of CPUs, running an
228 arbitrary number of tasks and interrupt contexts) cause a
229 deadlock.
230
231 In short, this feature enables the kernel to report locking
232 related deadlocks before they actually occur.
233
234 The proof does not depend on how hard and complex a
235 deadlock scenario would be to trigger: how many
236 participant CPUs, tasks and irq-contexts would be needed
237 for it to trigger. The proof also does not depend on
238 timing: if a race and a resulting deadlock is possible
239 theoretically (no matter how unlikely the race scenario
240 is), it will be proven so and will immediately be
241 reported by the kernel (once the event is observed that
242 makes the deadlock theoretically possible).
243
244 If a deadlock is impossible (i.e. the locking rules, as
245 observed by the kernel, are mathematically correct), the
246 kernel reports nothing.
247
248 NOTE: this feature can also be enabled for rwlocks, mutexes
249 and rwsems - in which case all dependencies between these
250 different locking variants are observed and mapped too, and
251 the proof of observed correctness is also maintained for an
252 arbitrary combination of these separate locking variants.
253
254 For more details, see Documentation/lockdep-design.txt.
255
256config LOCKDEP
257 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700258 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700259 select STACKTRACE
Franck Bui-Huu14cf2322007-04-26 00:20:15 -0700260 select FRAME_POINTER if !X86 && !MIPS
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700261 select KALLSYMS
262 select KALLSYMS_ALL
263
264config DEBUG_LOCKDEP
265 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700266 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700267 help
268 If you say Y here, the lock dependency engine will do
269 additional runtime checks to debug itself, at the price
270 of more runtime overhead.
271
272config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700273 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700274 bool
275 default y
276 depends on TRACE_IRQFLAGS_SUPPORT
277 depends on PROVE_LOCKING
278
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700280 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 depends on DEBUG_KERNEL
282 help
283 If you say Y here, various routines which may sleep will become very
284 noisy if they are called with a spinlock held.
285
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700286config DEBUG_LOCKING_API_SELFTESTS
287 bool "Locking API boot-time self-tests"
288 depends on DEBUG_KERNEL
289 help
290 Say Y here if you want the kernel to run a short self-test during
291 bootup. The self-test checks whether common types of locking bugs
292 are detected by debugging mechanisms or not. (if you disable
293 lock debugging then those bugs wont be detected of course.)
294 The following locking APIs are covered: spinlocks, rwlocks,
295 mutexes and rwsems.
296
Ingo Molnar8637c092006-07-03 00:24:38 -0700297config STACKTRACE
298 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700299 depends on DEBUG_KERNEL
Ingo Molnar8637c092006-07-03 00:24:38 -0700300 depends on STACKTRACE_SUPPORT
301
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302config DEBUG_KOBJECT
303 bool "kobject debugging"
304 depends on DEBUG_KERNEL
305 help
306 If you say Y here, some extra kobject debugging messages will be sent
307 to the syslog.
308
309config DEBUG_HIGHMEM
310 bool "Highmem debugging"
311 depends on DEBUG_KERNEL && HIGHMEM
312 help
313 This options enables addition error checking for high memory systems.
314 Disable for production systems.
315
316config DEBUG_BUGVERBOSE
317 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700318 depends on BUG
Bryan Wu1394f032007-05-06 14:50:22 -0700319 depends on ARM || ARM26 || AVR32 || M32R || M68K || SPARC32 || SPARC64 || FRV || SUPERH || GENERIC_BUG || BFIN
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 default !EMBEDDED
321 help
322 Say Y here to make BUG() panics output the file name and line number
323 of the BUG call as well as the EIP and oops trace. This aids
324 debugging but costs about 70-100K of memory.
325
326config DEBUG_INFO
327 bool "Compile the kernel with debug info"
328 depends on DEBUG_KERNEL
329 help
330 If you say Y here the resulting kernel image will include
331 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600332 This adds debug symbols to the kernel and modules (gcc -g), and
333 is needed if you intend to use kernel crashdump or binary object
334 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 Say Y here only if you plan to debug the kernel.
336
337 If unsure, say N.
338
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800339config DEBUG_VM
340 bool "Debug VM"
341 depends on DEBUG_KERNEL
342 help
Nick Piggin13e74442006-01-06 00:10:58 -0800343 Enable this to turn on extended checks in the virtual-memory system
344 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800345
346 If unsure, say N.
347
Dave Jones199a9af2006-09-29 01:59:00 -0700348config DEBUG_LIST
349 bool "Debug linked list manipulation"
350 depends on DEBUG_KERNEL
351 help
352 Enable this to turn on extended checks in the linked-list
353 walking routines.
354
355 If unsure, say N.
356
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357config FRAME_POINTER
358 bool "Compile the kernel with frame pointers"
Bryan Wu1394f032007-05-06 14:50:22 -0700359 depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390 || AVR32 || SUPERH || BFIN)
Paolo 'Blaisorblade' Giarrusso37fce852005-05-28 15:51:59 -0700360 default y if DEBUG_INFO && UML
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 help
362 If you say Y here the resulting kernel image will be slightly larger
Jesper Juhl2a38bcc2005-10-30 15:02:51 -0800363 and slower, but it might give very useful debugging information on
364 some architectures or if you use external debuggers.
Andi Kleenaeb39982005-09-12 18:49:25 +0200365 If you don't debug the kernel, you can say N.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366
Ingo Molnara9df3d02006-01-14 13:21:33 -0800367config FORCED_INLINING
368 bool "Force gcc to inline functions marked 'inline'"
369 depends on DEBUG_KERNEL
370 default y
371 help
372 This option determines if the kernel forces gcc to inline the functions
373 developers have marked 'inline'. Doing so takes away freedom from gcc to
374 do what it thinks is best, which is desirable for the gcc 3.x series of
375 compilers. The gcc 4.x series have a rewritten inlining algorithm and
376 disabling this option will generate a smaller kernel there. Hopefully
377 this algorithm is so good that allowing gcc4 to make the decision can
378 become the default in the future, until then this option is there to
379 test gcc for this.
380
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800381config RCU_TORTURE_TEST
382 tristate "torture tests for RCU"
383 depends on DEBUG_KERNEL
Paul E. McKenney9aaffc82007-05-23 13:57:41 -0700384 depends on m
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800385 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
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800391 Say M if you want the RCU torture tests to build as a module.
392 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700393
394config LKDTM
395 tristate "Linux Kernel Dump Test Tool Module"
Don Mullisbf4735a2006-12-10 02:18:37 -0800396 depends on DEBUG_KERNEL
Ankita Garg8bb31b92006-10-02 02:17:36 -0700397 depends on KPROBES
398 default n
399 help
400 This module enables testing of the different dumping mechanisms by
401 inducing system failures at predefined crash points.
402 If you don't need it: say N
403 Choose M here to compile this code as a module. The module will be
404 called lkdtm.
405
406 Documentation on how to use the module can be found in
407 drivers/misc/lkdtm.c
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800408
409config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800410 bool "Fault-injection framework"
411 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -0800412 help
413 Provide fault-injection framework.
414 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800415
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800416config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800417 bool "Fault-injection capability for kmalloc"
418 depends on FAULT_INJECTION
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800419 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800420 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800421
Akinobu Mita933e3122006-12-08 02:39:45 -0800422config FAIL_PAGE_ALLOC
423 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800424 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800425 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800426 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800427
Akinobu Mitac17bb492006-12-08 02:39:46 -0800428config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100429 bool "Fault-injection capability for disk IO"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800430 depends on FAULT_INJECTION
Akinobu Mitac17bb492006-12-08 02:39:46 -0800431 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800432 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800433
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800434config FAULT_INJECTION_DEBUG_FS
435 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800436 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800437 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800438 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -0800439
440config FAULT_INJECTION_STACKTRACE_FILTER
441 bool "stacktrace filter for fault-injection capabilities"
442 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -0700443 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -0800444 select STACKTRACE
445 select FRAME_POINTER
446 help
447 Provide stacktrace filter for fault-injection capabilities