blob: 5c2681875b9ac31b1a363c63d909120cbc82b930 [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
Linus Torvalds1da177e2005-04-16 15:20:36 -070080config LOG_BUF_SHIFT
81 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
82 range 12 21
Ingo Molnarfbb9ce92006-07-03 00:24:50 -070083 default 17 if S390 || LOCKDEP
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 default 16 if X86_NUMAQ || IA64
85 default 15 if SMP
86 default 14
87 help
88 Select kernel log buffer size as a power of 2.
89 Defaults and Examples:
90 17 => 128 KB for S/390
91 16 => 64 KB for x86 NUMAQ or IA-64
92 15 => 32 KB for SMP
93 14 => 16 KB for uniprocessor
94 13 => 8 KB
95 12 => 4 KB
96
Ingo Molnar8446f1d2005-09-06 15:16:27 -070097config DETECT_SOFTLOCKUP
98 bool "Detect Soft Lockups"
Heiko Carstensdea20a32006-10-11 01:20:44 -070099 depends on DEBUG_KERNEL && !S390
Ingo Molnar8446f1d2005-09-06 15:16:27 -0700100 default y
101 help
102 Say Y here to enable the kernel to detect "soft lockups",
103 which are bugs that cause the kernel to loop in kernel
104 mode for more than 10 seconds, without giving other tasks a
105 chance to run.
106
107 When a soft-lockup is detected, the kernel will print the
108 current stack trace (which you should report), but the
109 system will stay locked up. This feature has negligible
110 overhead.
111
112 (Note that "hard lockups" are separate type of bugs that
113 can be detected via the NMI-watchdog, on platforms that
114 support it.)
115
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116config SCHEDSTATS
117 bool "Collect scheduler statistics"
118 depends on DEBUG_KERNEL && PROC_FS
119 help
120 If you say Y here, additional code will be inserted into the
121 scheduler and related routines to collect statistics about
122 scheduler behavior and provide them in /proc/schedstat. These
123 stats may be useful for both tuning and debugging the scheduler
124 If you aren't debugging the scheduler or trying to tune a specific
125 application, you can say N to avoid the very slight overhead
126 this adds.
127
128config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800129 bool "Debug slab memory allocations"
Ingo Molnar50dd26b2006-01-08 01:01:42 -0800130 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 help
132 Say Y here to have the kernel do limited verification on memory
133 allocation as well as poisoning memory on free to catch use of freed
134 memory. This can make kmalloc/kfree-intensive workloads much slower.
135
Al Viro871751e2006-03-25 03:06:39 -0800136config DEBUG_SLAB_LEAK
137 bool "Memory leak debugging"
138 depends on DEBUG_SLAB
139
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140config DEBUG_PREEMPT
141 bool "Debug preemptible kernel"
Ingo Molnar8637c092006-07-03 00:24:38 -0700142 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 default y
144 help
145 If you say Y here then the kernel will use a debug variant of the
146 commonly used smp_processor_id() function and will print warnings
147 if kernel code uses it in a preemption-unsafe way. Also, the kernel
148 will detect preemption count underflows.
149
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700150config DEBUG_RT_MUTEXES
151 bool "RT Mutex debugging, deadlock detection"
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700152 depends on DEBUG_KERNEL && RT_MUTEXES
153 help
154 This allows rt mutex semantics violations and rt mutex related
155 deadlocks (lockups) to be detected and reported automatically.
156
157config DEBUG_PI_LIST
158 bool
159 default y
160 depends on DEBUG_RT_MUTEXES
161
Thomas Gleixner61a87122006-06-27 02:54:56 -0700162config RT_MUTEX_TESTER
163 bool "Built-in scriptable tester for rt-mutexes"
Roman Zippela1583d32006-06-27 02:55:00 -0700164 depends on DEBUG_KERNEL && RT_MUTEXES
Thomas Gleixner61a87122006-06-27 02:54:56 -0700165 help
166 This option enables a rt-mutex tester.
167
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700169 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 depends on DEBUG_KERNEL
171 help
172 Say Y here and build SMP to catch missing spinlock initialization
173 and certain other kinds of spinlock errors commonly made. This is
174 best used in conjunction with the NMI watchdog so that spinlock
175 deadlocks are also debuggable.
176
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700177config DEBUG_MUTEXES
178 bool "Mutex debugging: basic checks"
179 depends on DEBUG_KERNEL
180 help
181 This feature allows mutex semantics violations to be detected and
182 reported.
183
184config DEBUG_RWSEMS
185 bool "RW-sem debugging: basic checks"
186 depends on DEBUG_KERNEL
187 help
188 This feature allows read-write semaphore semantics violations to
189 be detected and reported.
190
191config DEBUG_LOCK_ALLOC
192 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700193 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700194 select DEBUG_SPINLOCK
195 select DEBUG_MUTEXES
196 select DEBUG_RWSEMS
197 select LOCKDEP
198 help
199 This feature will check whether any held lock (spinlock, rwlock,
200 mutex or rwsem) is incorrectly freed by the kernel, via any of the
201 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
202 vfree(), etc.), whether a live lock is incorrectly reinitialized via
203 spin_lock_init()/mutex_init()/etc., or whether there is any lock
204 held during task exit.
205
206config PROVE_LOCKING
207 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700208 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700209 select LOCKDEP
210 select DEBUG_SPINLOCK
211 select DEBUG_MUTEXES
212 select DEBUG_RWSEMS
213 select DEBUG_LOCK_ALLOC
214 default n
215 help
216 This feature enables the kernel to prove that all locking
217 that occurs in the kernel runtime is mathematically
218 correct: that under no circumstance could an arbitrary (and
219 not yet triggered) combination of observed locking
220 sequences (on an arbitrary number of CPUs, running an
221 arbitrary number of tasks and interrupt contexts) cause a
222 deadlock.
223
224 In short, this feature enables the kernel to report locking
225 related deadlocks before they actually occur.
226
227 The proof does not depend on how hard and complex a
228 deadlock scenario would be to trigger: how many
229 participant CPUs, tasks and irq-contexts would be needed
230 for it to trigger. The proof also does not depend on
231 timing: if a race and a resulting deadlock is possible
232 theoretically (no matter how unlikely the race scenario
233 is), it will be proven so and will immediately be
234 reported by the kernel (once the event is observed that
235 makes the deadlock theoretically possible).
236
237 If a deadlock is impossible (i.e. the locking rules, as
238 observed by the kernel, are mathematically correct), the
239 kernel reports nothing.
240
241 NOTE: this feature can also be enabled for rwlocks, mutexes
242 and rwsems - in which case all dependencies between these
243 different locking variants are observed and mapped too, and
244 the proof of observed correctness is also maintained for an
245 arbitrary combination of these separate locking variants.
246
247 For more details, see Documentation/lockdep-design.txt.
248
249config LOCKDEP
250 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700251 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700252 select STACKTRACE
Andi Kleen3b8d1fe2006-09-26 10:52:34 +0200253 select FRAME_POINTER if !X86
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700254 select KALLSYMS
255 select KALLSYMS_ALL
256
257config DEBUG_LOCKDEP
258 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700259 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700260 help
261 If you say Y here, the lock dependency engine will do
262 additional runtime checks to debug itself, at the price
263 of more runtime overhead.
264
265config TRACE_IRQFLAGS
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700266 depends on DEBUG_KERNEL
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700267 bool
268 default y
269 depends on TRACE_IRQFLAGS_SUPPORT
270 depends on PROVE_LOCKING
271
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272config DEBUG_SPINLOCK_SLEEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700273 bool "Spinlock debugging: sleep-inside-spinlock checking"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 depends on DEBUG_KERNEL
275 help
276 If you say Y here, various routines which may sleep will become very
277 noisy if they are called with a spinlock held.
278
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700279config DEBUG_LOCKING_API_SELFTESTS
280 bool "Locking API boot-time self-tests"
281 depends on DEBUG_KERNEL
282 help
283 Say Y here if you want the kernel to run a short self-test during
284 bootup. The self-test checks whether common types of locking bugs
285 are detected by debugging mechanisms or not. (if you disable
286 lock debugging then those bugs wont be detected of course.)
287 The following locking APIs are covered: spinlocks, rwlocks,
288 mutexes and rwsems.
289
Ingo Molnar8637c092006-07-03 00:24:38 -0700290config STACKTRACE
291 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700292 depends on DEBUG_KERNEL
Ingo Molnar8637c092006-07-03 00:24:38 -0700293 depends on STACKTRACE_SUPPORT
294
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295config DEBUG_KOBJECT
296 bool "kobject debugging"
297 depends on DEBUG_KERNEL
298 help
299 If you say Y here, some extra kobject debugging messages will be sent
300 to the syslog.
301
302config DEBUG_HIGHMEM
303 bool "Highmem debugging"
304 depends on DEBUG_KERNEL && HIGHMEM
305 help
306 This options enables addition error checking for high memory systems.
307 Disable for production systems.
308
309config DEBUG_BUGVERBOSE
310 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700311 depends on BUG
Jeremy Fitzhardinge91768d62006-12-08 02:36:21 -0800312 depends on ARM || ARM26 || AVR32 || M32R || M68K || SPARC32 || SPARC64 || FRV || SUPERH || GENERIC_BUG
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 default !EMBEDDED
314 help
315 Say Y here to make BUG() panics output the file name and line number
316 of the BUG call as well as the EIP and oops trace. This aids
317 debugging but costs about 70-100K of memory.
318
319config DEBUG_INFO
320 bool "Compile the kernel with debug info"
321 depends on DEBUG_KERNEL
322 help
323 If you say Y here the resulting kernel image will include
324 debugging info resulting in a larger kernel image.
325 Say Y here only if you plan to debug the kernel.
326
327 If unsure, say N.
328
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800329config DEBUG_VM
330 bool "Debug VM"
331 depends on DEBUG_KERNEL
332 help
Nick Piggin13e74442006-01-06 00:10:58 -0800333 Enable this to turn on extended checks in the virtual-memory system
334 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800335
336 If unsure, say N.
337
Dave Jones199a9af2006-09-29 01:59:00 -0700338config DEBUG_LIST
339 bool "Debug linked list manipulation"
340 depends on DEBUG_KERNEL
341 help
342 Enable this to turn on extended checks in the linked-list
343 walking routines.
344
345 If unsure, say N.
346
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347config FRAME_POINTER
348 bool "Compile the kernel with frame pointers"
Paul Mundt2549b322006-09-27 16:22:33 +0900349 depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390 || AVR32 || SUPERH)
Paolo 'Blaisorblade' Giarrusso37fce852005-05-28 15:51:59 -0700350 default y if DEBUG_INFO && UML
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 help
352 If you say Y here the resulting kernel image will be slightly larger
Jesper Juhl2a38bcc2005-10-30 15:02:51 -0800353 and slower, but it might give very useful debugging information on
354 some architectures or if you use external debuggers.
Andi Kleenaeb39982005-09-12 18:49:25 +0200355 If you don't debug the kernel, you can say N.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356
Ingo Molnara9df3d02006-01-14 13:21:33 -0800357config FORCED_INLINING
358 bool "Force gcc to inline functions marked 'inline'"
359 depends on DEBUG_KERNEL
360 default y
361 help
362 This option determines if the kernel forces gcc to inline the functions
363 developers have marked 'inline'. Doing so takes away freedom from gcc to
364 do what it thinks is best, which is desirable for the gcc 3.x series of
365 compilers. The gcc 4.x series have a rewritten inlining algorithm and
366 disabling this option will generate a smaller kernel there. Hopefully
367 this algorithm is so good that allowing gcc4 to make the decision can
368 become the default in the future, until then this option is there to
369 test gcc for this.
370
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800371config RCU_TORTURE_TEST
372 tristate "torture tests for RCU"
373 depends on DEBUG_KERNEL
374 default n
375 help
376 This option provides a kernel module that runs torture tests
377 on the RCU infrastructure. The kernel module may be built
378 after the fact on the running kernel to be tested, if desired.
379
380 Say Y here if you want RCU torture tests to start automatically
381 at boot time (you probably don't).
382 Say M if you want the RCU torture tests to build as a module.
383 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -0700384
385config LKDTM
386 tristate "Linux Kernel Dump Test Tool Module"
Don Mullisbf4735a2006-12-10 02:18:37 -0800387 depends on DEBUG_KERNEL
Ankita Garg8bb31b92006-10-02 02:17:36 -0700388 depends on KPROBES
389 default n
390 help
391 This module enables testing of the different dumping mechanisms by
392 inducing system failures at predefined crash points.
393 If you don't need it: say N
394 Choose M here to compile this code as a module. The module will be
395 called lkdtm.
396
397 Documentation on how to use the module can be found in
398 drivers/misc/lkdtm.c
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800399
400config FAULT_INJECTION
Andrew Morton1ab85092006-12-08 02:39:49 -0800401 bool "Fault-injection framework"
402 depends on DEBUG_KERNEL
Andrew Morton83ba2542006-12-08 02:39:49 -0800403 depends on STACKTRACE
Akinobu Mita329409a2006-12-08 02:39:48 -0800404 select FRAME_POINTER
405 help
406 Provide fault-injection framework.
407 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800408
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800409config FAILSLAB
Andrew Morton1ab85092006-12-08 02:39:49 -0800410 bool "Fault-injection capability for kmalloc"
411 depends on FAULT_INJECTION
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800412 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800413 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -0800414
Akinobu Mita933e3122006-12-08 02:39:45 -0800415config FAIL_PAGE_ALLOC
416 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab85092006-12-08 02:39:49 -0800417 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -0800418 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800419 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -0800420
Akinobu Mitac17bb492006-12-08 02:39:46 -0800421config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +0100422 bool "Fault-injection capability for disk IO"
Andrew Morton1ab85092006-12-08 02:39:49 -0800423 depends on FAULT_INJECTION
Akinobu Mitac17bb492006-12-08 02:39:46 -0800424 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800425 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -0800426
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800427config FAULT_INJECTION_DEBUG_FS
428 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab85092006-12-08 02:39:49 -0800429 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800430 help
Andrew Morton1ab85092006-12-08 02:39:49 -0800431 Enable configuration of fault-injection capabilities via debugfs.