blob: 6eccc643c32edc3e2b11920ba17c1bd73ba11609 [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
Adrian Bunkf346f4b2006-01-09 20:54:51 -080050config DEBUG_KERNEL
51 bool "Kernel debugging"
52 help
53 Say Y here if you are developing drivers or trying to debug and
54 identify kernel problems.
55
Linus Torvalds1da177e2005-04-16 15:20:36 -070056config LOG_BUF_SHIFT
57 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
58 range 12 21
Ingo Molnarfbb9ce952006-07-03 00:24:50 -070059 default 17 if S390 || LOCKDEP
Linus Torvalds1da177e2005-04-16 15:20:36 -070060 default 16 if X86_NUMAQ || IA64
61 default 15 if SMP
62 default 14
63 help
64 Select kernel log buffer size as a power of 2.
65 Defaults and Examples:
66 17 => 128 KB for S/390
67 16 => 64 KB for x86 NUMAQ or IA-64
68 15 => 32 KB for SMP
69 14 => 16 KB for uniprocessor
70 13 => 8 KB
71 12 => 4 KB
72
Ingo Molnar8446f1d2005-09-06 15:16:27 -070073config DETECT_SOFTLOCKUP
74 bool "Detect Soft Lockups"
Heiko Carstensdea20a32006-10-11 01:20:44 -070075 depends on DEBUG_KERNEL && !S390
Ingo Molnar8446f1d2005-09-06 15:16:27 -070076 default y
77 help
78 Say Y here to enable the kernel to detect "soft lockups",
79 which are bugs that cause the kernel to loop in kernel
80 mode for more than 10 seconds, without giving other tasks a
81 chance to run.
82
83 When a soft-lockup is detected, the kernel will print the
84 current stack trace (which you should report), but the
85 system will stay locked up. This feature has negligible
86 overhead.
87
88 (Note that "hard lockups" are separate type of bugs that
89 can be detected via the NMI-watchdog, on platforms that
90 support it.)
91
Linus Torvalds1da177e2005-04-16 15:20:36 -070092config SCHEDSTATS
93 bool "Collect scheduler statistics"
94 depends on DEBUG_KERNEL && PROC_FS
95 help
96 If you say Y here, additional code will be inserted into the
97 scheduler and related routines to collect statistics about
98 scheduler behavior and provide them in /proc/schedstat. These
99 stats may be useful for both tuning and debugging the scheduler
100 If you aren't debugging the scheduler or trying to tune a specific
101 application, you can say N to avoid the very slight overhead
102 this adds.
103
104config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800105 bool "Debug slab memory allocations"
Ingo Molnar50dd26ba2006-01-08 01:01:42 -0800106 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 help
108 Say Y here to have the kernel do limited verification on memory
109 allocation as well as poisoning memory on free to catch use of freed
110 memory. This can make kmalloc/kfree-intensive workloads much slower.
111
Al Viro871751e2006-03-25 03:06:39 -0800112config DEBUG_SLAB_LEAK
113 bool "Memory leak debugging"
114 depends on DEBUG_SLAB
115
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116config DEBUG_PREEMPT
117 bool "Debug preemptible kernel"
Ingo Molnar8637c092006-07-03 00:24:38 -0700118 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 default y
120 help
121 If you say Y here then the kernel will use a debug variant of the
122 commonly used smp_processor_id() function and will print warnings
123 if kernel code uses it in a preemption-unsafe way. Also, the kernel
124 will detect preemption count underflows.
125
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700126config DEBUG_RT_MUTEXES
127 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700128 depends on DEBUG_KERNEL && RT_MUTEXES
129 help
130 This allows rt mutex semantics violations and rt mutex related
131 deadlocks (lockups) to be detected and reported automatically.
132
133config DEBUG_PI_LIST
134 bool
135 default y
136 depends on DEBUG_RT_MUTEXES
137
Thomas Gleixner61a87122006-06-27 02:54:56 -0700138config RT_MUTEX_TESTER
139 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700140 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700141 help
142 This option enables a rt-mutex tester.
143
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700145 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 depends on DEBUG_KERNEL
147 help
148 Say Y here and build SMP to catch missing spinlock initialization
149 and certain other kinds of spinlock errors commonly made. This is
150 best used in conjunction with the NMI watchdog so that spinlock
151 deadlocks are also debuggable.
152
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700153config DEBUG_MUTEXES
154 bool "Mutex debugging: basic checks"
155 depends on DEBUG_KERNEL
156 help
157 This feature allows mutex semantics violations to be detected and
158 reported.
159
160config DEBUG_RWSEMS
161 bool "RW-sem debugging: basic checks"
162 depends on DEBUG_KERNEL
163 help
164 This feature allows read-write semaphore semantics violations to
165 be detected and reported.
166
167config DEBUG_LOCK_ALLOC
168 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700169 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700170 select DEBUG_SPINLOCK
171 select DEBUG_MUTEXES
172 select DEBUG_RWSEMS
173 select LOCKDEP
174 help
175 This feature will check whether any held lock (spinlock, rwlock,
176 mutex or rwsem) is incorrectly freed by the kernel, via any of the
177 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
178 vfree(), etc.), whether a live lock is incorrectly reinitialized via
179 spin_lock_init()/mutex_init()/etc., or whether there is any lock
180 held during task exit.
181
182config PROVE_LOCKING
183 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700184 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700185 select LOCKDEP
186 select DEBUG_SPINLOCK
187 select DEBUG_MUTEXES
188 select DEBUG_RWSEMS
189 select DEBUG_LOCK_ALLOC
190 default n
191 help
192 This feature enables the kernel to prove that all locking
193 that occurs in the kernel runtime is mathematically
194 correct: that under no circumstance could an arbitrary (and
195 not yet triggered) combination of observed locking
196 sequences (on an arbitrary number of CPUs, running an
197 arbitrary number of tasks and interrupt contexts) cause a
198 deadlock.
199
200 In short, this feature enables the kernel to report locking
201 related deadlocks before they actually occur.
202
203 The proof does not depend on how hard and complex a
204 deadlock scenario would be to trigger: how many
205 participant CPUs, tasks and irq-contexts would be needed
206 for it to trigger. The proof also does not depend on
207 timing: if a race and a resulting deadlock is possible
208 theoretically (no matter how unlikely the race scenario
209 is), it will be proven so and will immediately be
210 reported by the kernel (once the event is observed that
211 makes the deadlock theoretically possible).
212
213 If a deadlock is impossible (i.e. the locking rules, as
214 observed by the kernel, are mathematically correct), the
215 kernel reports nothing.
216
217 NOTE: this feature can also be enabled for rwlocks, mutexes
218 and rwsems - in which case all dependencies between these
219 different locking variants are observed and mapped too, and
220 the proof of observed correctness is also maintained for an
221 arbitrary combination of these separate locking variants.
222
223 For more details, see Documentation/lockdep-design.txt.
224
225config LOCKDEP
226 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700227 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700228 select STACKTRACE
Andi Kleen3b8d1fe2006-09-26 10:52:34 +0200229 select FRAME_POINTER if !X86
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700230 select KALLSYMS
231 select KALLSYMS_ALL
232
233config DEBUG_LOCKDEP
234 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700235 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700236 help
237 If you say Y here, the lock dependency engine will do
238 additional runtime checks to debug itself, at the price
239 of more runtime overhead.
240
241config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700242 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700243 bool
244 default y
245 depends on TRACE_IRQFLAGS_SUPPORT
246 depends on PROVE_LOCKING
247
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700249 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 depends on DEBUG_KERNEL
251 help
252 If you say Y here, various routines which may sleep will become very
253 noisy if they are called with a spinlock held.
254
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700255config DEBUG_LOCKING_API_SELFTESTS
256 bool "Locking API boot-time self-tests"
257 depends on DEBUG_KERNEL
258 help
259 Say Y here if you want the kernel to run a short self-test during
260 bootup. The self-test checks whether common types of locking bugs
261 are detected by debugging mechanisms or not. (if you disable
262 lock debugging then those bugs wont be detected of course.)
263 The following locking APIs are covered: spinlocks, rwlocks,
264 mutexes and rwsems.
265
Ingo Molnar8637c092006-07-03 00:24:38 -0700266config STACKTRACE
267 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700268 depends on DEBUG_KERNEL
Ingo Molnar8637c092006-07-03 00:24:38 -0700269 depends on STACKTRACE_SUPPORT
270
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271config DEBUG_KOBJECT
272 bool "kobject debugging"
273 depends on DEBUG_KERNEL
274 help
275 If you say Y here, some extra kobject debugging messages will be sent
276 to the syslog.
277
278config DEBUG_HIGHMEM
279 bool "Highmem debugging"
280 depends on DEBUG_KERNEL && HIGHMEM
281 help
282 This options enables addition error checking for high memory systems.
283 Disable for production systems.
284
285config DEBUG_BUGVERBOSE
286 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700287 depends on BUG
Jeremy Fitzhardinge91768d62006-12-08 02:36:21 -0800288 depends on ARM || ARM26 || AVR32 || M32R || M68K || SPARC32 || SPARC64 || FRV || SUPERH || GENERIC_BUG
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 default !EMBEDDED
290 help
291 Say Y here to make BUG() panics output the file name and line number
292 of the BUG call as well as the EIP and oops trace. This aids
293 debugging but costs about 70-100K of memory.
294
295config DEBUG_INFO
296 bool "Compile the kernel with debug info"
297 depends on DEBUG_KERNEL
298 help
299 If you say Y here the resulting kernel image will include
300 debugging info resulting in a larger kernel image.
301 Say Y here only if you plan to debug the kernel.
302
303 If unsure, say N.
304
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305config DEBUG_FS
306 bool "Debug Filesystem"
Jens Axboeae36b882006-03-26 14:38:54 +0200307 depends on SYSFS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 help
309 debugfs is a virtual file system that kernel developers use to put
310 debugging files into. Enable this option to be able to read and
311 write to these files.
312
313 If unsure, say N.
314
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800315config DEBUG_VM
316 bool "Debug VM"
317 depends on DEBUG_KERNEL
318 help
Nick Piggin13e74442006-01-06 00:10:58 -0800319 Enable this to turn on extended checks in the virtual-memory system
320 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800321
322 If unsure, say N.
323
Dave Jones199a9af2006-09-29 01:59:00 -0700324config DEBUG_LIST
325 bool "Debug linked list manipulation"
326 depends on DEBUG_KERNEL
327 help
328 Enable this to turn on extended checks in the linked-list
329 walking routines.
330
331 If unsure, say N.
332
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333config FRAME_POINTER
334 bool "Compile the kernel with frame pointers"
Paul Mundt2549b322006-09-27 16:22:33 +0900335 depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390 || AVR32 || SUPERH)
Paolo 'Blaisorblade' Giarrusso37fce852005-05-28 15:51:59 -0700336 default y if DEBUG_INFO && UML
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 help
338 If you say Y here the resulting kernel image will be slightly larger
Jesper Juhl2a38bcc2005-10-30 15:02:51 -0800339 and slower, but it might give very useful debugging information on
340 some architectures or if you use external debuggers.
Andi Kleenaeb39982005-09-12 18:49:25 +0200341 If you don't debug the kernel, you can say N.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342
Jan Beulich604bf5a2006-03-24 03:16:19 -0800343config UNWIND_INFO
344 bool "Compile the kernel with frame unwind information"
Kevin Hilman75e31aa2006-10-25 23:07:50 +0100345 depends on !IA64 && !PARISC && !ARM
Jan Beulich4552d5d2006-06-26 13:57:28 +0200346 depends on !MODULES || !(MIPS || PPC || SUPERH || V850)
Jan Beulich604bf5a2006-03-24 03:16:19 -0800347 help
348 If you say Y here the resulting kernel image will be slightly larger
349 but not slower, and it will give very useful debugging information.
350 If you don't debug the kernel, you can say N, but we may not be able
351 to solve problems without frame unwind information or frame pointers.
352
Jan Beulich4552d5d2006-06-26 13:57:28 +0200353config STACK_UNWIND
354 bool "Stack unwind support"
355 depends on UNWIND_INFO
Jan Beulich176a2712006-06-26 13:57:41 +0200356 depends on X86
Jan Beulich4552d5d2006-06-26 13:57:28 +0200357 help
358 This enables more precise stack traces, omitting all unrelated
359 occurrences of pointers into kernel code from the dump.
360
Ingo Molnara9df3d02006-01-14 13:21:33 -0800361config FORCED_INLINING
362 bool "Force gcc to inline functions marked 'inline'"
363 depends on DEBUG_KERNEL
364 default y
365 help
366 This option determines if the kernel forces gcc to inline the functions
367 developers have marked 'inline'. Doing so takes away freedom from gcc to
368 do what it thinks is best, which is desirable for the gcc 3.x series of
369 compilers. The gcc 4.x series have a rewritten inlining algorithm and
370 disabling this option will generate a smaller kernel there. Hopefully
371 this algorithm is so good that allowing gcc4 to make the decision can
372 become the default in the future, until then this option is there to
373 test gcc for this.
374
David Woodhouse0f836e5f2006-10-11 01:21:43 -0700375config HEADERS_CHECK
376 bool "Run 'make headers_check' when building vmlinux"
Al Viro1b958172006-10-12 19:10:04 +0100377 depends on !UML
David Woodhouse0f836e5f2006-10-11 01:21:43 -0700378 help
379 This option will extract the user-visible kernel headers whenever
380 building the kernel, and will run basic sanity checks on them to
381 ensure that exported files do not attempt to include files which
382 were not exported, etc.
383
384 If you're making modifications to header files which are
385 relevant for userspace, say 'Y', and check the headers
386 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
387 your build tree), to make sure they're suitable.
388
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800389config RCU_TORTURE_TEST
390 tristate "torture tests for RCU"
391 depends on DEBUG_KERNEL
392 default n
393 help
394 This option provides a kernel module that runs torture tests
395 on the RCU infrastructure. The kernel module may be built
396 after the fact on the running kernel to be tested, if desired.
397
398 Say Y here if you want RCU torture tests to start automatically
399 at boot time (you probably don't).
400 Say M if you want the RCU torture tests to build as a module.
401 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700402
403config LKDTM
404 tristate "Linux Kernel Dump Test Tool Module"
405 depends on KPROBES
406 default n
407 help
408 This module enables testing of the different dumping mechanisms by
409 inducing system failures at predefined crash points.
410 If you don't need it: say N
411 Choose M here to compile this code as a module. The module will be
412 called lkdtm.
413
414 Documentation on how to use the module can be found in
415 drivers/misc/lkdtm.c
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800416
417config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800418 bool "Fault-injection framework"
419 depends on DEBUG_KERNEL
Andrew Morton83ba2542006-12-08 02:39:49 -0800420 depends on STACKTRACE
Akinobu Mita329409a2006-12-08 02:39:48 -0800421 select FRAME_POINTER
422 help
423 Provide fault-injection framework.
424 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800425
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800426config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800427 bool "Fault-injection capability for kmalloc"
428 depends on FAULT_INJECTION
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800429 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800430 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800431
Akinobu Mita933e3122006-12-08 02:39:45 -0800432config FAIL_PAGE_ALLOC
433 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800434 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800435 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800436 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800437
Akinobu Mitac17bb492006-12-08 02:39:46 -0800438config FAIL_MAKE_REQUEST
439 bool "Fault-injection capabilitiy for disk IO"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800440 depends on FAULT_INJECTION
Akinobu Mitac17bb492006-12-08 02:39:46 -0800441 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800442 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800443
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800444config FAULT_INJECTION_DEBUG_FS
445 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800446 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800447 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -0800448 Enable configuration of fault-injection capabilities via debugfs.