blob: fbc5c622acb05db13d5cb5d248e42837470b1ca4 [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
129 about timer usage patterns in kernel and userspace.
130
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800132 bool "Debug slab memory allocations"
Ingo Molnar50dd26ba2006-01-08 01:01:42 -0800133 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 help
135 Say Y here to have the kernel do limited verification on memory
136 allocation as well as poisoning memory on free to catch use of freed
137 memory. This can make kmalloc/kfree-intensive workloads much slower.
138
Al Viro871751e2006-03-25 03:06:39 -0800139config DEBUG_SLAB_LEAK
140 bool "Memory leak debugging"
141 depends on DEBUG_SLAB
142
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143config DEBUG_PREEMPT
144 bool "Debug preemptible kernel"
Ingo Molnar8637c092006-07-03 00:24:38 -0700145 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 default y
147 help
148 If you say Y here then the kernel will use a debug variant of the
149 commonly used smp_processor_id() function and will print warnings
150 if kernel code uses it in a preemption-unsafe way. Also, the kernel
151 will detect preemption count underflows.
152
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700153config DEBUG_RT_MUTEXES
154 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700155 depends on DEBUG_KERNEL && RT_MUTEXES
156 help
157 This allows rt mutex semantics violations and rt mutex related
158 deadlocks (lockups) to be detected and reported automatically.
159
160config DEBUG_PI_LIST
161 bool
162 default y
163 depends on DEBUG_RT_MUTEXES
164
Thomas Gleixner61a87122006-06-27 02:54:56 -0700165config RT_MUTEX_TESTER
166 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700167 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700168 help
169 This option enables a rt-mutex tester.
170
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700172 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 depends on DEBUG_KERNEL
174 help
175 Say Y here and build SMP to catch missing spinlock initialization
176 and certain other kinds of spinlock errors commonly made. This is
177 best used in conjunction with the NMI watchdog so that spinlock
178 deadlocks are also debuggable.
179
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700180config DEBUG_MUTEXES
181 bool "Mutex debugging: basic checks"
182 depends on DEBUG_KERNEL
183 help
184 This feature allows mutex semantics violations to be detected and
185 reported.
186
Robert P. J. Dayc761c842007-05-08 00:25:02 -0700187config DEBUG_SEMAPHORE
188 bool "Semaphore debugging"
189 depends on DEBUG_KERNEL
190 depends on ALPHA || FRV
191 default n
192 help
193 If you say Y here then semaphore processing will issue lots of
194 verbose debugging messages. If you suspect a semaphore problem or a
195 kernel hacker asks for this option then say Y. Otherwise say N.
196
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700197config DEBUG_LOCK_ALLOC
198 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700199 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700200 select DEBUG_SPINLOCK
201 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700202 select LOCKDEP
203 help
204 This feature will check whether any held lock (spinlock, rwlock,
205 mutex or rwsem) is incorrectly freed by the kernel, via any of the
206 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
207 vfree(), etc.), whether a live lock is incorrectly reinitialized via
208 spin_lock_init()/mutex_init()/etc., or whether there is any lock
209 held during task exit.
210
211config PROVE_LOCKING
212 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700213 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700214 select LOCKDEP
215 select DEBUG_SPINLOCK
216 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700217 select DEBUG_LOCK_ALLOC
218 default n
219 help
220 This feature enables the kernel to prove that all locking
221 that occurs in the kernel runtime is mathematically
222 correct: that under no circumstance could an arbitrary (and
223 not yet triggered) combination of observed locking
224 sequences (on an arbitrary number of CPUs, running an
225 arbitrary number of tasks and interrupt contexts) cause a
226 deadlock.
227
228 In short, this feature enables the kernel to report locking
229 related deadlocks before they actually occur.
230
231 The proof does not depend on how hard and complex a
232 deadlock scenario would be to trigger: how many
233 participant CPUs, tasks and irq-contexts would be needed
234 for it to trigger. The proof also does not depend on
235 timing: if a race and a resulting deadlock is possible
236 theoretically (no matter how unlikely the race scenario
237 is), it will be proven so and will immediately be
238 reported by the kernel (once the event is observed that
239 makes the deadlock theoretically possible).
240
241 If a deadlock is impossible (i.e. the locking rules, as
242 observed by the kernel, are mathematically correct), the
243 kernel reports nothing.
244
245 NOTE: this feature can also be enabled for rwlocks, mutexes
246 and rwsems - in which case all dependencies between these
247 different locking variants are observed and mapped too, and
248 the proof of observed correctness is also maintained for an
249 arbitrary combination of these separate locking variants.
250
251 For more details, see Documentation/lockdep-design.txt.
252
253config LOCKDEP
254 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700255 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700256 select STACKTRACE
Franck Bui-Huu14cf2322007-04-26 00:20:15 -0700257 select FRAME_POINTER if !X86 && !MIPS
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700258 select KALLSYMS
259 select KALLSYMS_ALL
260
261config DEBUG_LOCKDEP
262 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700263 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700264 help
265 If you say Y here, the lock dependency engine will do
266 additional runtime checks to debug itself, at the price
267 of more runtime overhead.
268
269config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700270 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700271 bool
272 default y
273 depends on TRACE_IRQFLAGS_SUPPORT
274 depends on PROVE_LOCKING
275
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700277 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 depends on DEBUG_KERNEL
279 help
280 If you say Y here, various routines which may sleep will become very
281 noisy if they are called with a spinlock held.
282
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700283config DEBUG_LOCKING_API_SELFTESTS
284 bool "Locking API boot-time self-tests"
285 depends on DEBUG_KERNEL
286 help
287 Say Y here if you want the kernel to run a short self-test during
288 bootup. The self-test checks whether common types of locking bugs
289 are detected by debugging mechanisms or not. (if you disable
290 lock debugging then those bugs wont be detected of course.)
291 The following locking APIs are covered: spinlocks, rwlocks,
292 mutexes and rwsems.
293
Ingo Molnar8637c092006-07-03 00:24:38 -0700294config STACKTRACE
295 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700296 depends on DEBUG_KERNEL
Ingo Molnar8637c092006-07-03 00:24:38 -0700297 depends on STACKTRACE_SUPPORT
298
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299config DEBUG_KOBJECT
300 bool "kobject debugging"
301 depends on DEBUG_KERNEL
302 help
303 If you say Y here, some extra kobject debugging messages will be sent
304 to the syslog.
305
306config DEBUG_HIGHMEM
307 bool "Highmem debugging"
308 depends on DEBUG_KERNEL && HIGHMEM
309 help
310 This options enables addition error checking for high memory systems.
311 Disable for production systems.
312
313config DEBUG_BUGVERBOSE
314 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700315 depends on BUG
Bryan Wu1394f032007-05-06 14:50:22 -0700316 depends on ARM || ARM26 || AVR32 || M32R || M68K || SPARC32 || SPARC64 || FRV || SUPERH || GENERIC_BUG || BFIN
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 default !EMBEDDED
318 help
319 Say Y here to make BUG() panics output the file name and line number
320 of the BUG call as well as the EIP and oops trace. This aids
321 debugging but costs about 70-100K of memory.
322
323config DEBUG_INFO
324 bool "Compile the kernel with debug info"
325 depends on DEBUG_KERNEL
326 help
327 If you say Y here the resulting kernel image will include
328 debugging info resulting in a larger kernel image.
Andreas Dilgerb72e53f2007-03-27 15:21:33 -0600329 This adds debug symbols to the kernel and modules (gcc -g), and
330 is needed if you intend to use kernel crashdump or binary object
331 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332 Say Y here only if you plan to debug the kernel.
333
334 If unsure, say N.
335
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800336config DEBUG_VM
337 bool "Debug VM"
338 depends on DEBUG_KERNEL
339 help
Nick Piggin13e74442006-01-06 00:10:58 -0800340 Enable this to turn on extended checks in the virtual-memory system
341 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800342
343 If unsure, say N.
344
Dave Jones199a9af2006-09-29 01:59:00 -0700345config DEBUG_LIST
346 bool "Debug linked list manipulation"
347 depends on DEBUG_KERNEL
348 help
349 Enable this to turn on extended checks in the linked-list
350 walking routines.
351
352 If unsure, say N.
353
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354config FRAME_POINTER
355 bool "Compile the kernel with frame pointers"
Bryan Wu1394f032007-05-06 14:50:22 -0700356 depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390 || AVR32 || SUPERH || BFIN)
Paolo 'Blaisorblade' Giarrusso37fce852005-05-28 15:51:59 -0700357 default y if DEBUG_INFO && UML
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 help
359 If you say Y here the resulting kernel image will be slightly larger
Jesper Juhl2a38bcc2005-10-30 15:02:51 -0800360 and slower, but it might give very useful debugging information on
361 some architectures or if you use external debuggers.
Andi Kleenaeb39982005-09-12 18:49:25 +0200362 If you don't debug the kernel, you can say N.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363
Ingo Molnara9df3d02006-01-14 13:21:33 -0800364config FORCED_INLINING
365 bool "Force gcc to inline functions marked 'inline'"
366 depends on DEBUG_KERNEL
367 default y
368 help
369 This option determines if the kernel forces gcc to inline the functions
370 developers have marked 'inline'. Doing so takes away freedom from gcc to
371 do what it thinks is best, which is desirable for the gcc 3.x series of
372 compilers. The gcc 4.x series have a rewritten inlining algorithm and
373 disabling this option will generate a smaller kernel there. Hopefully
374 this algorithm is so good that allowing gcc4 to make the decision can
375 become the default in the future, until then this option is there to
376 test gcc for this.
377
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800378config RCU_TORTURE_TEST
379 tristate "torture tests for RCU"
380 depends on DEBUG_KERNEL
381 default n
382 help
383 This option provides a kernel module that runs torture tests
384 on the RCU infrastructure. The kernel module may be built
385 after the fact on the running kernel to be tested, if desired.
386
387 Say Y here if you want RCU torture tests to start automatically
388 at boot time (you probably don't).
389 Say M if you want the RCU torture tests to build as a module.
390 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700391
392config LKDTM
393 tristate "Linux Kernel Dump Test Tool Module"
Don Mullisbf4735a2006-12-10 02:18:37 -0800394 depends on DEBUG_KERNEL
Ankita Garg8bb31b92006-10-02 02:17:36 -0700395 depends on KPROBES
396 default n
397 help
398 This module enables testing of the different dumping mechanisms by
399 inducing system failures at predefined crash points.
400 If you don't need it: say N
401 Choose M here to compile this code as a module. The module will be
402 called lkdtm.
403
404 Documentation on how to use the module can be found in
405 drivers/misc/lkdtm.c
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800406
407config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800408 bool "Fault-injection framework"
409 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -0800410 help
411 Provide fault-injection framework.
412 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800413
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800414config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800415 bool "Fault-injection capability for kmalloc"
416 depends on FAULT_INJECTION
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800417 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800418 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800419
Akinobu Mita933e3122006-12-08 02:39:45 -0800420config FAIL_PAGE_ALLOC
421 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800422 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800423 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800424 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800425
Akinobu Mitac17bb492006-12-08 02:39:46 -0800426config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100427 bool "Fault-injection capability for disk IO"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800428 depends on FAULT_INJECTION
Akinobu Mitac17bb492006-12-08 02:39:46 -0800429 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800430 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800431
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800432config FAULT_INJECTION_DEBUG_FS
433 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800434 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800435 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800436 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -0800437
438config FAULT_INJECTION_STACKTRACE_FILTER
439 bool "stacktrace filter for fault-injection capabilities"
440 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -0700441 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -0800442 select STACKTRACE
443 select FRAME_POINTER
444 help
445 Provide stacktrace filter for fault-injection capabilities