Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | |
2 | config PRINTK_TIME | |
3 | bool "Show timing information on printks" | |
d3b8b6e5 | 4 | depends on PRINTK |
1da177e4 LT |
5 | 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 | ||
de488443 JG |
12 | config ENABLE_WARN_DEPRECATED |
13 | bool "Enable __deprecated logic" | |
14 | default y | |
15 | help | |
16 | Enable the __deprecated logic in the kernel build. | |
17 | Disable this to suppress the "warning: 'foo' is deprecated | |
18 | (declared at kernel/power/somefile.c:1234)" messages. | |
19 | ||
cebc04ba AM |
20 | config ENABLE_MUST_CHECK |
21 | bool "Enable __must_check logic" | |
22 | default y | |
23 | help | |
24 | Enable the __must_check logic in the kernel build. Disable this to | |
25 | suppress the "warning: ignoring return value of 'foo', declared with | |
26 | attribute warn_unused_result" messages. | |
1da177e4 | 27 | |
35bb5b1e AK |
28 | config FRAME_WARN |
29 | int "Warn for stack frames larger than (needs gcc 4.4)" | |
30 | range 0 8192 | |
31 | default 1024 if !64BIT | |
32 | default 2048 if 64BIT | |
33 | help | |
34 | Tell gcc to warn at build time for stack frames larger than this. | |
35 | Setting this too low will cause a lot of warnings. | |
36 | Setting it to 0 disables the warning. | |
37 | Requires gcc 4.4 | |
38 | ||
1da177e4 LT |
39 | config MAGIC_SYSRQ |
40 | bool "Magic SysRq key" | |
f346f4b3 | 41 | depends on !UML |
1da177e4 LT |
42 | help |
43 | If you say Y here, you will have some control over the system even | |
44 | if the system crashes for example during kernel debugging (e.g., you | |
45 | will be able to flush the buffer cache to disk, reboot the system | |
46 | immediately or dump some status information). This is accomplished | |
47 | by pressing various keys while holding SysRq (Alt+PrintScreen). It | |
48 | also works on a serial console (on PC hardware at least), if you | |
49 | send a BREAK and then within 5 seconds a command keypress. The | |
50 | keys are documented in <file:Documentation/sysrq.txt>. Don't say Y | |
51 | unless you really know what this hack does. | |
52 | ||
f71d20e9 AV |
53 | config UNUSED_SYMBOLS |
54 | bool "Enable unused/obsolete exported symbols" | |
55 | default y if X86 | |
56 | help | |
57 | Unused but exported symbols make the kernel needlessly bigger. For | |
58 | that reason most of these unused exports will soon be removed. This | |
59 | option is provided temporarily to provide a transition period in case | |
60 | some external kernel module needs one of these symbols anyway. If you | |
61 | encounter such a case in your module, consider if you are actually | |
62 | using the right API. (rationale: since nobody in the kernel is using | |
63 | this in a module, there is a pretty good chance it's actually the | |
64 | wrong interface to use). If you really need the symbol, please send a | |
65 | mail to the linux kernel mailing list mentioning the symbol and why | |
66 | you really need it, and what the merge plan to the mainline kernel for | |
67 | your module is. | |
68 | ||
bf4735a4 DM |
69 | config DEBUG_FS |
70 | bool "Debug Filesystem" | |
71 | depends on SYSFS | |
72 | help | |
73 | debugfs is a virtual file system that kernel developers use to put | |
74 | debugging files into. Enable this option to be able to read and | |
75 | write to these files. | |
76 | ||
ff543332 RD |
77 | For detailed documentation on the debugfs API, see |
78 | Documentation/DocBook/filesystems. | |
79 | ||
bf4735a4 DM |
80 | If unsure, say N. |
81 | ||
82 | config HEADERS_CHECK | |
83 | bool "Run 'make headers_check' when building vmlinux" | |
84 | depends on !UML | |
85 | help | |
86 | This option will extract the user-visible kernel headers whenever | |
87 | building the kernel, and will run basic sanity checks on them to | |
88 | ensure that exported files do not attempt to include files which | |
89 | were not exported, etc. | |
90 | ||
91 | If you're making modifications to header files which are | |
92 | relevant for userspace, say 'Y', and check the headers | |
93 | exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in | |
94 | your build tree), to make sure they're suitable. | |
95 | ||
91341d4b SR |
96 | config DEBUG_SECTION_MISMATCH |
97 | bool "Enable full Section mismatch analysis" | |
e5f95c8b | 98 | depends on UNDEFINED |
fa2144ba SR |
99 | # This option is on purpose disabled for now. |
100 | # It will be enabled when we are down to a resonable number | |
101 | # of section mismatch warnings (< 10 for an allyesconfig build) | |
91341d4b SR |
102 | help |
103 | The section mismatch analysis checks if there are illegal | |
104 | references from one section to another section. | |
105 | Linux will during link or during runtime drop some sections | |
106 | and any use of code/data previously in these sections will | |
107 | most likely result in an oops. | |
108 | In the code functions and variables are annotated with | |
109 | __init, __devinit etc. (see full list in include/linux/init.h) | |
d6fbfa4f GU |
110 | which results in the code/data being placed in specific sections. |
111 | The section mismatch analysis is always done after a full | |
112 | kernel build but enabling this option will in addition | |
91341d4b SR |
113 | do the following: |
114 | - Add the option -fno-inline-functions-called-once to gcc | |
115 | When inlining a function annotated __init in a non-init | |
d6fbfa4f | 116 | function we would lose the section information and thus |
91341d4b | 117 | the analysis would not catch the illegal reference. |
d6fbfa4f | 118 | This option tells gcc to inline less but will also |
91341d4b SR |
119 | result in a larger kernel. |
120 | - Run the section mismatch analysis for each module/built-in.o | |
121 | When we run the section mismatch analysis on vmlinux.o we | |
d6fbfa4f | 122 | lose valueble information about where the mismatch was |
91341d4b SR |
123 | introduced. |
124 | Running the analysis for each module/built-in.o file | |
125 | will tell where the mismatch happens much closer to the | |
126 | source. The drawback is that we will report the same | |
127 | mismatch at least twice. | |
588ccd73 SR |
128 | - Enable verbose reporting from modpost to help solving |
129 | the section mismatches reported. | |
91341d4b | 130 | |
f346f4b3 AB |
131 | config DEBUG_KERNEL |
132 | bool "Kernel debugging" | |
133 | help | |
134 | Say Y here if you are developing drivers or trying to debug and | |
135 | identify kernel problems. | |
136 | ||
a304e1b8 DW |
137 | config DEBUG_SHIRQ |
138 | bool "Debug shared IRQ handlers" | |
139 | depends on DEBUG_KERNEL && GENERIC_HARDIRQS | |
140 | help | |
141 | Enable this to generate a spurious interrupt as soon as a shared | |
142 | interrupt handler is registered, and just before one is deregistered. | |
143 | Drivers ought to be able to handle interrupts coming in at those | |
144 | points; some don't and need to be caught. | |
145 | ||
8446f1d3 IM |
146 | config DETECT_SOFTLOCKUP |
147 | bool "Detect Soft Lockups" | |
dea20a3f | 148 | depends on DEBUG_KERNEL && !S390 |
8446f1d3 IM |
149 | default y |
150 | help | |
151 | Say Y here to enable the kernel to detect "soft lockups", | |
152 | which are bugs that cause the kernel to loop in kernel | |
9c44bc03 | 153 | mode for more than 60 seconds, without giving other tasks a |
8446f1d3 IM |
154 | chance to run. |
155 | ||
156 | When a soft-lockup is detected, the kernel will print the | |
157 | current stack trace (which you should report), but the | |
158 | system will stay locked up. This feature has negligible | |
159 | overhead. | |
160 | ||
161 | (Note that "hard lockups" are separate type of bugs that | |
162 | can be detected via the NMI-watchdog, on platforms that | |
163 | support it.) | |
164 | ||
9c44bc03 IM |
165 | config BOOTPARAM_SOFTLOCKUP_PANIC |
166 | bool "Panic (Reboot) On Soft Lockups" | |
167 | depends on DETECT_SOFTLOCKUP | |
168 | help | |
169 | Say Y here to enable the kernel to panic on "soft lockups", | |
170 | which are bugs that cause the kernel to loop in kernel | |
171 | mode for more than 60 seconds, without giving other tasks a | |
172 | chance to run. | |
173 | ||
174 | The panic can be used in combination with panic_timeout, | |
175 | to cause the system to reboot automatically after a | |
176 | lockup has been detected. This feature is useful for | |
177 | high-availability systems that have uptime guarantees and | |
178 | where a lockup must be resolved ASAP. | |
179 | ||
180 | Say N if unsure. | |
181 | ||
182 | config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE | |
183 | int | |
184 | depends on DETECT_SOFTLOCKUP | |
185 | range 0 1 | |
186 | default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC | |
187 | default 1 if BOOTPARAM_SOFTLOCKUP_PANIC | |
188 | ||
e162b39a MSB |
189 | config DETECT_HUNG_TASK |
190 | bool "Detect Hung Tasks" | |
191 | depends on DEBUG_KERNEL | |
77d05632 | 192 | default DETECT_SOFTLOCKUP |
e162b39a MSB |
193 | help |
194 | Say Y here to enable the kernel to detect "hung tasks", | |
195 | which are bugs that cause the task to be stuck in | |
196 | uninterruptible "D" state indefinitiley. | |
197 | ||
198 | When a hung task is detected, the kernel will print the | |
199 | current stack trace (which you should report), but the | |
200 | task will stay in uninterruptible state. If lockdep is | |
201 | enabled then all held locks will also be reported. This | |
202 | feature has negligible overhead. | |
203 | ||
204 | config BOOTPARAM_HUNG_TASK_PANIC | |
205 | bool "Panic (Reboot) On Hung Tasks" | |
206 | depends on DETECT_HUNG_TASK | |
207 | help | |
208 | Say Y here to enable the kernel to panic on "hung tasks", | |
209 | which are bugs that cause the kernel to leave a task stuck | |
210 | in uninterruptible "D" state. | |
211 | ||
212 | The panic can be used in combination with panic_timeout, | |
213 | to cause the system to reboot automatically after a | |
214 | hung task has been detected. This feature is useful for | |
215 | high-availability systems that have uptime guarantees and | |
216 | where a hung tasks must be resolved ASAP. | |
217 | ||
218 | Say N if unsure. | |
219 | ||
220 | config BOOTPARAM_HUNG_TASK_PANIC_VALUE | |
221 | int | |
222 | depends on DETECT_HUNG_TASK | |
223 | range 0 1 | |
224 | default 0 if !BOOTPARAM_HUNG_TASK_PANIC | |
225 | default 1 if BOOTPARAM_HUNG_TASK_PANIC | |
226 | ||
b642b6d3 IM |
227 | config SCHED_DEBUG |
228 | bool "Collect scheduler debugging info" | |
229 | depends on DEBUG_KERNEL && PROC_FS | |
230 | default y | |
231 | help | |
232 | If you say Y here, the /proc/sched_debug file will be provided | |
233 | that can help debug the scheduler. The runtime overhead of this | |
234 | option is minimal. | |
235 | ||
1da177e4 LT |
236 | config SCHEDSTATS |
237 | bool "Collect scheduler statistics" | |
238 | depends on DEBUG_KERNEL && PROC_FS | |
239 | help | |
240 | If you say Y here, additional code will be inserted into the | |
241 | scheduler and related routines to collect statistics about | |
242 | scheduler behavior and provide them in /proc/schedstat. These | |
243 | stats may be useful for both tuning and debugging the scheduler | |
244 | If you aren't debugging the scheduler or trying to tune a specific | |
245 | application, you can say N to avoid the very slight overhead | |
246 | this adds. | |
247 | ||
82f67cd9 IM |
248 | config TIMER_STATS |
249 | bool "Collect kernel timers statistics" | |
250 | depends on DEBUG_KERNEL && PROC_FS | |
251 | help | |
252 | If you say Y here, additional code will be inserted into the | |
253 | timer routines to collect statistics about kernel timers being | |
254 | reprogrammed. The statistics can be read from /proc/timer_stats. | |
255 | The statistics collection is started by writing 1 to /proc/timer_stats, | |
256 | writing 0 stops it. This feature is useful to collect information | |
c1a834dc IM |
257 | about timer usage patterns in kernel and userspace. This feature |
258 | is lightweight if enabled in the kernel config but not activated | |
259 | (it defaults to deactivated on bootup and will only be activated | |
260 | if some application like powertop activates it explicitly). | |
82f67cd9 | 261 | |
3ac7fe5a TG |
262 | config DEBUG_OBJECTS |
263 | bool "Debug object operations" | |
264 | depends on DEBUG_KERNEL | |
265 | help | |
266 | If you say Y here, additional code will be inserted into the | |
267 | kernel to track the life time of various objects and validate | |
268 | the operations on those objects. | |
269 | ||
270 | config DEBUG_OBJECTS_SELFTEST | |
271 | bool "Debug objects selftest" | |
272 | depends on DEBUG_OBJECTS | |
273 | help | |
274 | This enables the selftest of the object debug code. | |
275 | ||
276 | config DEBUG_OBJECTS_FREE | |
277 | bool "Debug objects in freed memory" | |
278 | depends on DEBUG_OBJECTS | |
279 | help | |
280 | This enables checks whether a k/v free operation frees an area | |
281 | which contains an object which has not been deactivated | |
282 | properly. This can make kmalloc/kfree-intensive workloads | |
283 | much slower. | |
284 | ||
c6f3a97f TG |
285 | config DEBUG_OBJECTS_TIMERS |
286 | bool "Debug timer objects" | |
287 | depends on DEBUG_OBJECTS | |
288 | help | |
289 | If you say Y here, additional code will be inserted into the | |
290 | timer routines to track the life time of timer objects and | |
291 | validate the timer operations. | |
292 | ||
3ae70205 IM |
293 | config DEBUG_OBJECTS_ENABLE_DEFAULT |
294 | int "debug_objects bootup default value (0-1)" | |
295 | range 0 1 | |
296 | default "1" | |
297 | depends on DEBUG_OBJECTS | |
298 | help | |
299 | Debug objects boot parameter default value | |
300 | ||
1da177e4 | 301 | config DEBUG_SLAB |
4a2f0acf | 302 | bool "Debug slab memory allocations" |
50dd26ba | 303 | depends on DEBUG_KERNEL && SLAB |
1da177e4 LT |
304 | help |
305 | Say Y here to have the kernel do limited verification on memory | |
306 | allocation as well as poisoning memory on free to catch use of freed | |
307 | memory. This can make kmalloc/kfree-intensive workloads much slower. | |
308 | ||
871751e2 AV |
309 | config DEBUG_SLAB_LEAK |
310 | bool "Memory leak debugging" | |
311 | depends on DEBUG_SLAB | |
312 | ||
f0630fff CL |
313 | config SLUB_DEBUG_ON |
314 | bool "SLUB debugging on by default" | |
315 | depends on SLUB && SLUB_DEBUG | |
316 | default n | |
317 | help | |
318 | Boot with debugging on by default. SLUB boots by default with | |
319 | the runtime debug capabilities switched off. Enabling this is | |
320 | equivalent to specifying the "slub_debug" parameter on boot. | |
321 | There is no support for more fine grained debug control like | |
322 | possible with slub_debug=xxx. SLUB debugging may be switched | |
323 | off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying | |
324 | "slub_debug=-". | |
325 | ||
8ff12cfc CL |
326 | config SLUB_STATS |
327 | default n | |
328 | bool "Enable SLUB performance statistics" | |
5b06c853 | 329 | depends on SLUB && SLUB_DEBUG && SYSFS |
8ff12cfc CL |
330 | help |
331 | SLUB statistics are useful to debug SLUBs allocation behavior in | |
332 | order find ways to optimize the allocator. This should never be | |
333 | enabled for production use since keeping statistics slows down | |
334 | the allocator by a few percentage points. The slabinfo command | |
335 | supports the determination of the most active slabs to figure | |
336 | out which slabs are relevant to a particular load. | |
337 | Try running: slabinfo -DA | |
338 | ||
1da177e4 LT |
339 | config DEBUG_PREEMPT |
340 | bool "Debug preemptible kernel" | |
048c8bc9 | 341 | depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64) |
1da177e4 LT |
342 | default y |
343 | help | |
344 | If you say Y here then the kernel will use a debug variant of the | |
345 | commonly used smp_processor_id() function and will print warnings | |
346 | if kernel code uses it in a preemption-unsafe way. Also, the kernel | |
347 | will detect preemption count underflows. | |
348 | ||
e7eebaf6 IM |
349 | config DEBUG_RT_MUTEXES |
350 | bool "RT Mutex debugging, deadlock detection" | |
e7eebaf6 IM |
351 | depends on DEBUG_KERNEL && RT_MUTEXES |
352 | help | |
353 | This allows rt mutex semantics violations and rt mutex related | |
354 | deadlocks (lockups) to be detected and reported automatically. | |
355 | ||
356 | config DEBUG_PI_LIST | |
357 | bool | |
358 | default y | |
359 | depends on DEBUG_RT_MUTEXES | |
360 | ||
61a87122 TG |
361 | config RT_MUTEX_TESTER |
362 | bool "Built-in scriptable tester for rt-mutexes" | |
a1583d3e | 363 | depends on DEBUG_KERNEL && RT_MUTEXES |
61a87122 TG |
364 | help |
365 | This option enables a rt-mutex tester. | |
366 | ||
1da177e4 | 367 | config DEBUG_SPINLOCK |
4d9f34ad | 368 | bool "Spinlock and rw-lock debugging: basic checks" |
1da177e4 LT |
369 | depends on DEBUG_KERNEL |
370 | help | |
371 | Say Y here and build SMP to catch missing spinlock initialization | |
372 | and certain other kinds of spinlock errors commonly made. This is | |
373 | best used in conjunction with the NMI watchdog so that spinlock | |
374 | deadlocks are also debuggable. | |
375 | ||
4d9f34ad IM |
376 | config DEBUG_MUTEXES |
377 | bool "Mutex debugging: basic checks" | |
378 | depends on DEBUG_KERNEL | |
379 | help | |
380 | This feature allows mutex semantics violations to be detected and | |
381 | reported. | |
382 | ||
4d9f34ad IM |
383 | config DEBUG_LOCK_ALLOC |
384 | bool "Lock debugging: detect incorrect freeing of live locks" | |
517e7aa5 | 385 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
386 | select DEBUG_SPINLOCK |
387 | select DEBUG_MUTEXES | |
4d9f34ad IM |
388 | select LOCKDEP |
389 | help | |
390 | This feature will check whether any held lock (spinlock, rwlock, | |
391 | mutex or rwsem) is incorrectly freed by the kernel, via any of the | |
392 | memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), | |
393 | vfree(), etc.), whether a live lock is incorrectly reinitialized via | |
394 | spin_lock_init()/mutex_init()/etc., or whether there is any lock | |
395 | held during task exit. | |
396 | ||
397 | config PROVE_LOCKING | |
398 | bool "Lock debugging: prove locking correctness" | |
517e7aa5 | 399 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
400 | select LOCKDEP |
401 | select DEBUG_SPINLOCK | |
402 | select DEBUG_MUTEXES | |
4d9f34ad IM |
403 | select DEBUG_LOCK_ALLOC |
404 | default n | |
405 | help | |
406 | This feature enables the kernel to prove that all locking | |
407 | that occurs in the kernel runtime is mathematically | |
408 | correct: that under no circumstance could an arbitrary (and | |
409 | not yet triggered) combination of observed locking | |
410 | sequences (on an arbitrary number of CPUs, running an | |
411 | arbitrary number of tasks and interrupt contexts) cause a | |
412 | deadlock. | |
413 | ||
414 | In short, this feature enables the kernel to report locking | |
415 | related deadlocks before they actually occur. | |
416 | ||
417 | The proof does not depend on how hard and complex a | |
418 | deadlock scenario would be to trigger: how many | |
419 | participant CPUs, tasks and irq-contexts would be needed | |
420 | for it to trigger. The proof also does not depend on | |
421 | timing: if a race and a resulting deadlock is possible | |
422 | theoretically (no matter how unlikely the race scenario | |
423 | is), it will be proven so and will immediately be | |
424 | reported by the kernel (once the event is observed that | |
425 | makes the deadlock theoretically possible). | |
426 | ||
427 | If a deadlock is impossible (i.e. the locking rules, as | |
428 | observed by the kernel, are mathematically correct), the | |
429 | kernel reports nothing. | |
430 | ||
431 | NOTE: this feature can also be enabled for rwlocks, mutexes | |
432 | and rwsems - in which case all dependencies between these | |
433 | different locking variants are observed and mapped too, and | |
434 | the proof of observed correctness is also maintained for an | |
435 | arbitrary combination of these separate locking variants. | |
436 | ||
437 | For more details, see Documentation/lockdep-design.txt. | |
438 | ||
439 | config LOCKDEP | |
440 | bool | |
517e7aa5 | 441 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad | 442 | select STACKTRACE |
75ee034a | 443 | select FRAME_POINTER if !X86 && !MIPS && !PPC && !ARM_UNWIND && !S390 |
4d9f34ad IM |
444 | select KALLSYMS |
445 | select KALLSYMS_ALL | |
446 | ||
f20786ff | 447 | config LOCK_STAT |
fdfb870f | 448 | bool "Lock usage statistics" |
f20786ff PZ |
449 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
450 | select LOCKDEP | |
451 | select DEBUG_SPINLOCK | |
452 | select DEBUG_MUTEXES | |
453 | select DEBUG_LOCK_ALLOC | |
454 | default n | |
455 | help | |
456 | This feature enables tracking lock contention points | |
457 | ||
a560aa48 PZ |
458 | For more details, see Documentation/lockstat.txt |
459 | ||
4d9f34ad IM |
460 | config DEBUG_LOCKDEP |
461 | bool "Lock dependency engine debugging" | |
517e7aa5 | 462 | depends on DEBUG_KERNEL && LOCKDEP |
4d9f34ad IM |
463 | help |
464 | If you say Y here, the lock dependency engine will do | |
465 | additional runtime checks to debug itself, at the price | |
466 | of more runtime overhead. | |
467 | ||
468 | config TRACE_IRQFLAGS | |
517e7aa5 | 469 | depends on DEBUG_KERNEL |
4d9f34ad IM |
470 | bool |
471 | default y | |
472 | depends on TRACE_IRQFLAGS_SUPPORT | |
473 | depends on PROVE_LOCKING | |
474 | ||
1da177e4 | 475 | config DEBUG_SPINLOCK_SLEEP |
4d9f34ad | 476 | bool "Spinlock debugging: sleep-inside-spinlock checking" |
1da177e4 LT |
477 | depends on DEBUG_KERNEL |
478 | help | |
479 | If you say Y here, various routines which may sleep will become very | |
480 | noisy if they are called with a spinlock held. | |
481 | ||
cae2ed9a IM |
482 | config DEBUG_LOCKING_API_SELFTESTS |
483 | bool "Locking API boot-time self-tests" | |
484 | depends on DEBUG_KERNEL | |
485 | help | |
486 | Say Y here if you want the kernel to run a short self-test during | |
487 | bootup. The self-test checks whether common types of locking bugs | |
488 | are detected by debugging mechanisms or not. (if you disable | |
489 | lock debugging then those bugs wont be detected of course.) | |
490 | The following locking APIs are covered: spinlocks, rwlocks, | |
491 | mutexes and rwsems. | |
492 | ||
8637c099 IM |
493 | config STACKTRACE |
494 | bool | |
495 | depends on STACKTRACE_SUPPORT | |
496 | ||
1da177e4 LT |
497 | config DEBUG_KOBJECT |
498 | bool "kobject debugging" | |
499 | depends on DEBUG_KERNEL | |
500 | help | |
501 | If you say Y here, some extra kobject debugging messages will be sent | |
502 | to the syslog. | |
503 | ||
504 | config DEBUG_HIGHMEM | |
505 | bool "Highmem debugging" | |
506 | depends on DEBUG_KERNEL && HIGHMEM | |
507 | help | |
508 | This options enables addition error checking for high memory systems. | |
509 | Disable for production systems. | |
510 | ||
511 | config DEBUG_BUGVERBOSE | |
512 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED | |
c8538a7a | 513 | depends on BUG |
b920de1b DH |
514 | depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \ |
515 | FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300 | |
1da177e4 LT |
516 | default !EMBEDDED |
517 | help | |
518 | Say Y here to make BUG() panics output the file name and line number | |
519 | of the BUG call as well as the EIP and oops trace. This aids | |
520 | debugging but costs about 70-100K of memory. | |
521 | ||
522 | config DEBUG_INFO | |
523 | bool "Compile the kernel with debug info" | |
524 | depends on DEBUG_KERNEL | |
525 | help | |
526 | If you say Y here the resulting kernel image will include | |
527 | debugging info resulting in a larger kernel image. | |
b72e53f8 AD |
528 | This adds debug symbols to the kernel and modules (gcc -g), and |
529 | is needed if you intend to use kernel crashdump or binary object | |
530 | tools like crash, kgdb, LKCD, gdb, etc on the kernel. | |
1da177e4 LT |
531 | Say Y here only if you plan to debug the kernel. |
532 | ||
533 | If unsure, say N. | |
534 | ||
a241ec65 PM |
535 | config DEBUG_VM |
536 | bool "Debug VM" | |
537 | depends on DEBUG_KERNEL | |
538 | help | |
13e7444b NP |
539 | Enable this to turn on extended checks in the virtual-memory system |
540 | that may impact performance. | |
a241ec65 PM |
541 | |
542 | If unsure, say N. | |
543 | ||
59ea7463 JS |
544 | config DEBUG_VIRTUAL |
545 | bool "Debug VM translations" | |
546 | depends on DEBUG_KERNEL && X86 | |
547 | help | |
548 | Enable some costly sanity checks in virtual to page code. This can | |
549 | catch mistakes with virt_to_page() and friends. | |
550 | ||
551 | If unsure, say N. | |
552 | ||
8feae131 DH |
553 | config DEBUG_NOMMU_REGIONS |
554 | bool "Debug the global anon/private NOMMU mapping region tree" | |
555 | depends on DEBUG_KERNEL && !MMU | |
556 | help | |
557 | This option causes the global tree of anonymous and private mapping | |
558 | regions to be regularly checked for invalid topology. | |
559 | ||
ad775f5a DH |
560 | config DEBUG_WRITECOUNT |
561 | bool "Debug filesystem writers count" | |
562 | depends on DEBUG_KERNEL | |
563 | help | |
564 | Enable this to catch wrong use of the writers count in struct | |
565 | vfsmount. This will increase the size of each file struct by | |
566 | 32 bits. | |
567 | ||
568 | If unsure, say N. | |
569 | ||
6b74ab97 MG |
570 | config DEBUG_MEMORY_INIT |
571 | bool "Debug memory initialisation" if EMBEDDED | |
572 | default !EMBEDDED | |
573 | help | |
574 | Enable this for additional checks during memory initialisation. | |
575 | The sanity checks verify aspects of the VM such as the memory model | |
576 | and other information provided by the architecture. Verbose | |
577 | information will be printed at KERN_DEBUG loglevel depending | |
578 | on the mminit_loglevel= command-line option. | |
579 | ||
580 | If unsure, say Y | |
581 | ||
199a9afc DJ |
582 | config DEBUG_LIST |
583 | bool "Debug linked list manipulation" | |
584 | depends on DEBUG_KERNEL | |
585 | help | |
586 | Enable this to turn on extended checks in the linked-list | |
587 | walking routines. | |
588 | ||
589 | If unsure, say N. | |
590 | ||
d6ec0842 JA |
591 | config DEBUG_SG |
592 | bool "Debug SG table operations" | |
593 | depends on DEBUG_KERNEL | |
594 | help | |
595 | Enable this to turn on checks on scatter-gather tables. This can | |
596 | help find problems with drivers that do not properly initialize | |
597 | their sg tables. | |
598 | ||
599 | If unsure, say N. | |
600 | ||
1b2439db AV |
601 | config DEBUG_NOTIFIERS |
602 | bool "Debug notifier call chains" | |
603 | depends on DEBUG_KERNEL | |
604 | help | |
605 | Enable this to turn on sanity checking for notifier call chains. | |
606 | This is most useful for kernel developers to make sure that | |
607 | modules properly unregister themselves from notifier chains. | |
608 | This is a relatively cheap check but if you care about maximum | |
609 | performance, say N. | |
610 | ||
64dec40d JM |
611 | # |
612 | # Select this config option from the architecture Kconfig, if it | |
613 | # it is preferred to always offer frame pointers as a config | |
614 | # option on the architecture (regardless of KERNEL_DEBUG): | |
615 | # | |
616 | config ARCH_WANT_FRAME_POINTERS | |
617 | bool | |
618 | help | |
619 | ||
1da177e4 LT |
620 | config FRAME_POINTER |
621 | bool "Compile the kernel with frame pointers" | |
b920de1b | 622 | depends on DEBUG_KERNEL && \ |
75ee034a | 623 | (CRIS || M68K || M68KNOMMU || FRV || UML || \ |
da4276b8 IM |
624 | AVR32 || SUPERH || BLACKFIN || MN10300) || \ |
625 | ARCH_WANT_FRAME_POINTERS | |
626 | default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS | |
627 | help | |
628 | If you say Y here the resulting kernel image will be slightly | |
629 | larger and slower, but it gives very useful debugging information | |
630 | in case of kernel bugs. (precise oopses/stacktraces/warnings) | |
1da177e4 | 631 | |
bfe8df3d RD |
632 | config BOOT_PRINTK_DELAY |
633 | bool "Delay each boot printk message by N milliseconds" | |
634 | depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY | |
635 | help | |
636 | This build option allows you to read kernel boot messages | |
637 | by inserting a short delay after each one. The delay is | |
638 | specified in milliseconds on the kernel command line, | |
639 | using "boot_delay=N". | |
640 | ||
641 | It is likely that you would also need to use "lpj=M" to preset | |
642 | the "loops per jiffie" value. | |
643 | See a previous boot log for the "lpj" value to use for your | |
644 | system, and then set "lpj=M" before setting "boot_delay=N". | |
645 | NOTE: Using this option may adversely affect SMP systems. | |
646 | I.e., processors other than the first one may not boot up. | |
647 | BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect | |
648 | what it believes to be lockup conditions. | |
649 | ||
a241ec65 PM |
650 | config RCU_TORTURE_TEST |
651 | tristate "torture tests for RCU" | |
652 | depends on DEBUG_KERNEL | |
653 | default n | |
654 | help | |
655 | This option provides a kernel module that runs torture tests | |
656 | on the RCU infrastructure. The kernel module may be built | |
657 | after the fact on the running kernel to be tested, if desired. | |
658 | ||
31a72bce PM |
659 | Say Y here if you want RCU torture tests to be built into |
660 | the kernel. | |
a241ec65 PM |
661 | Say M if you want the RCU torture tests to build as a module. |
662 | Say N if you are unsure. | |
8bb31b9d | 663 | |
31a72bce PM |
664 | config RCU_TORTURE_TEST_RUNNABLE |
665 | bool "torture tests for RCU runnable by default" | |
666 | depends on RCU_TORTURE_TEST = y | |
667 | default n | |
668 | help | |
669 | This option provides a way to build the RCU torture tests | |
670 | directly into the kernel without them starting up at boot | |
671 | time. You can use /proc/sys/kernel/rcutorture_runnable | |
672 | to manually override this setting. This /proc file is | |
673 | available only when the RCU torture tests have been built | |
674 | into the kernel. | |
675 | ||
676 | Say Y here if you want the RCU torture tests to start during | |
677 | boot (you probably don't). | |
678 | Say N here if you want the RCU torture tests to start only | |
679 | after being manually enabled via /proc. | |
680 | ||
64db4cff PM |
681 | config RCU_CPU_STALL_DETECTOR |
682 | bool "Check for stalled CPUs delaying RCU grace periods" | |
683 | depends on CLASSIC_RCU || TREE_RCU | |
684 | default n | |
685 | help | |
686 | This option causes RCU to printk information on which | |
687 | CPUs are delaying the current grace period, but only when | |
688 | the grace period extends for excessive time periods. | |
67182ae1 PM |
689 | |
690 | Say Y if you want RCU to perform such checks. | |
691 | ||
692 | Say N if you are unsure. | |
693 | ||
8c1c9356 AM |
694 | config KPROBES_SANITY_TEST |
695 | bool "Kprobes sanity tests" | |
696 | depends on DEBUG_KERNEL | |
697 | depends on KPROBES | |
698 | default n | |
699 | help | |
700 | This option provides for testing basic kprobes functionality on | |
701 | boot. A sample kprobe, jprobe and kretprobe are inserted and | |
702 | verified for functionality. | |
703 | ||
704 | Say N if you are unsure. | |
705 | ||
6dab2778 AV |
706 | config BACKTRACE_SELF_TEST |
707 | tristate "Self test for the backtrace code" | |
708 | depends on DEBUG_KERNEL | |
709 | default n | |
710 | help | |
711 | This option provides a kernel module that can be used to test | |
712 | the kernel stack backtrace code. This option is not useful | |
713 | for distributions or general kernels, but only for kernel | |
714 | developers working on architecture code. | |
715 | ||
ad118c54 VN |
716 | Note that if you want to also test saved backtraces, you will |
717 | have to enable STACKTRACE as well. | |
718 | ||
6dab2778 AV |
719 | Say N if you are unsure. |
720 | ||
870d6656 TH |
721 | config DEBUG_BLOCK_EXT_DEVT |
722 | bool "Force extended block device numbers and spread them" | |
723 | depends on DEBUG_KERNEL | |
724 | depends on BLOCK | |
759f8ca3 | 725 | default n |
870d6656 | 726 | help |
0e11e342 TH |
727 | BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON |
728 | SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT | |
729 | YOU ARE DOING. Distros, please enable this and fix whatever | |
730 | is broken. | |
731 | ||
870d6656 TH |
732 | Conventionally, block device numbers are allocated from |
733 | predetermined contiguous area. However, extended block area | |
734 | may introduce non-contiguous block device numbers. This | |
735 | option forces most block device numbers to be allocated from | |
736 | the extended space and spreads them to discover kernel or | |
737 | userland code paths which assume predetermined contiguous | |
738 | device number allocation. | |
739 | ||
55dc7db7 TH |
740 | Note that turning on this debug option shuffles all the |
741 | device numbers for all IDE and SCSI devices including libata | |
742 | ones, so root partition specified using device number | |
743 | directly (via rdev or root=MAJ:MIN) won't work anymore. | |
744 | Textual device names (root=/dev/sdXn) will continue to work. | |
745 | ||
870d6656 TH |
746 | Say N if you are unsure. |
747 | ||
8bb31b9d AG |
748 | config LKDTM |
749 | tristate "Linux Kernel Dump Test Tool Module" | |
bf4735a4 | 750 | depends on DEBUG_KERNEL |
8bb31b9d | 751 | depends on KPROBES |
fddd9cf8 | 752 | depends on BLOCK |
8bb31b9d AG |
753 | default n |
754 | help | |
755 | This module enables testing of the different dumping mechanisms by | |
756 | inducing system failures at predefined crash points. | |
757 | If you don't need it: say N | |
758 | Choose M here to compile this code as a module. The module will be | |
759 | called lkdtm. | |
760 | ||
761 | Documentation on how to use the module can be found in | |
762 | drivers/misc/lkdtm.c | |
6ff1cb35 AM |
763 | |
764 | config FAULT_INJECTION | |
1ab8509a AM |
765 | bool "Fault-injection framework" |
766 | depends on DEBUG_KERNEL | |
329409ae AM |
767 | help |
768 | Provide fault-injection framework. | |
769 | For more details, see Documentation/fault-injection/. | |
6ff1cb35 | 770 | |
8a8b6502 | 771 | config FAILSLAB |
1ab8509a AM |
772 | bool "Fault-injection capability for kmalloc" |
773 | depends on FAULT_INJECTION | |
773ff60e | 774 | depends on SLAB || SLUB |
8a8b6502 | 775 | help |
1ab8509a | 776 | Provide fault-injection capability for kmalloc. |
8a8b6502 | 777 | |
933e312e AM |
778 | config FAIL_PAGE_ALLOC |
779 | bool "Fault-injection capabilitiy for alloc_pages()" | |
1ab8509a | 780 | depends on FAULT_INJECTION |
933e312e | 781 | help |
1ab8509a | 782 | Provide fault-injection capability for alloc_pages(). |
933e312e | 783 | |
c17bb495 | 784 | config FAIL_MAKE_REQUEST |
86327d19 | 785 | bool "Fault-injection capability for disk IO" |
581d4e28 | 786 | depends on FAULT_INJECTION && BLOCK |
c17bb495 | 787 | help |
1ab8509a | 788 | Provide fault-injection capability for disk IO. |
c17bb495 | 789 | |
581d4e28 JA |
790 | config FAIL_IO_TIMEOUT |
791 | bool "Faul-injection capability for faking disk interrupts" | |
792 | depends on FAULT_INJECTION && BLOCK | |
793 | help | |
794 | Provide fault-injection capability on end IO handling. This | |
795 | will make the block layer "forget" an interrupt as configured, | |
796 | thus exercising the error handling. | |
797 | ||
798 | Only works with drivers that use the generic timeout handling, | |
799 | for others it wont do anything. | |
800 | ||
6ff1cb35 AM |
801 | config FAULT_INJECTION_DEBUG_FS |
802 | bool "Debugfs entries for fault-injection capabilities" | |
1ab8509a | 803 | depends on FAULT_INJECTION && SYSFS && DEBUG_FS |
6ff1cb35 | 804 | help |
1ab8509a | 805 | Enable configuration of fault-injection capabilities via debugfs. |
1df49008 AM |
806 | |
807 | config FAULT_INJECTION_STACKTRACE_FILTER | |
808 | bool "stacktrace filter for fault-injection capabilities" | |
809 | depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT | |
6d690dca | 810 | depends on !X86_64 |
1df49008 | 811 | select STACKTRACE |
75ee034a | 812 | select FRAME_POINTER if !PPC && !S390 |
1df49008 AM |
813 | help |
814 | Provide stacktrace filter for fault-injection capabilities | |
267c4025 | 815 | |
9745512c AV |
816 | config LATENCYTOP |
817 | bool "Latency measuring infrastructure" | |
75ee034a | 818 | select FRAME_POINTER if !MIPS && !PPC && !S390 |
9745512c AV |
819 | select KALLSYMS |
820 | select KALLSYMS_ALL | |
821 | select STACKTRACE | |
822 | select SCHEDSTATS | |
823 | select SCHED_DEBUG | |
aa7d9350 | 824 | depends on HAVE_LATENCYTOP_SUPPORT |
9745512c AV |
825 | help |
826 | Enable this option if you want to use the LatencyTOP tool | |
827 | to find out which userspace is blocking on what kernel operations. | |
828 | ||
9e94cd32 AK |
829 | config SYSCTL_SYSCALL_CHECK |
830 | bool "Sysctl checks" | |
831 | depends on SYSCTL_SYSCALL | |
832 | ---help--- | |
833 | sys_sysctl uses binary paths that have been found challenging | |
834 | to properly maintain and use. This enables checks that help | |
835 | you to keep things correct. | |
836 | ||
6a11f75b | 837 | source mm/Kconfig.debug |
16444a8a ACM |
838 | source kernel/trace/Kconfig |
839 | ||
f212ec4b | 840 | config PROVIDE_OHCI1394_DMA_INIT |
080de8c2 | 841 | bool "Remote debugging over FireWire early on boot" |
f212ec4b BK |
842 | depends on PCI && X86 |
843 | help | |
844 | If you want to debug problems which hang or crash the kernel early | |
845 | on boot and the crashing machine has a FireWire port, you can use | |
846 | this feature to remotely access the memory of the crashed machine | |
847 | over FireWire. This employs remote DMA as part of the OHCI1394 | |
848 | specification which is now the standard for FireWire controllers. | |
849 | ||
850 | With remote DMA, you can monitor the printk buffer remotely using | |
851 | firescope and access all memory below 4GB using fireproxy from gdb. | |
852 | Even controlling a kernel debugger is possible using remote DMA. | |
853 | ||
854 | Usage: | |
855 | ||
856 | If ohci1394_dma=early is used as boot parameter, it will initialize | |
857 | all OHCI1394 controllers which are found in the PCI config space. | |
858 | ||
859 | As all changes to the FireWire bus such as enabling and disabling | |
860 | devices cause a bus reset and thereby disable remote DMA for all | |
861 | devices, be sure to have the cable plugged and FireWire enabled on | |
862 | the debugging host before booting the debug target for debugging. | |
863 | ||
864 | This code (~1k) is freed after boot. By then, the firewire stack | |
865 | in charge of the OHCI-1394 controllers should be used instead. | |
866 | ||
867 | See Documentation/debugging-via-ohci1394.txt for more information. | |
9745512c | 868 | |
080de8c2 SR |
869 | config FIREWIRE_OHCI_REMOTE_DMA |
870 | bool "Remote debugging over FireWire with firewire-ohci" | |
871 | depends on FIREWIRE_OHCI | |
872 | help | |
873 | This option lets you use the FireWire bus for remote debugging | |
874 | with help of the firewire-ohci driver. It enables unfiltered | |
875 | remote DMA in firewire-ohci. | |
876 | See Documentation/debugging-via-ohci1394.txt for more information. | |
877 | ||
878 | If unsure, say N. | |
879 | ||
152de30b | 880 | config BUILD_DOCSRC |
3794f3e8 RD |
881 | bool "Build targets in Documentation/ tree" |
882 | depends on HEADERS_CHECK | |
883 | help | |
884 | This option attempts to build objects from the source files in the | |
885 | kernel Documentation/ tree. | |
886 | ||
887 | Say N if you are unsure. | |
888 | ||
e9d376f0 | 889 | config DYNAMIC_DEBUG |
86151fdf | 890 | bool "Enable dynamic printk() support" |
346e15be JB |
891 | default n |
892 | depends on PRINTK | |
86151fdf | 893 | depends on DEBUG_FS |
346e15be JB |
894 | help |
895 | ||
896 | Compiles debug level messages into the kernel, which would not | |
897 | otherwise be available at runtime. These messages can then be | |
86151fdf JB |
898 | enabled/disabled based on various levels of scope - per source file, |
899 | function, module, format string, and line number. This mechanism | |
900 | implicitly enables all pr_debug() and dev_dbg() calls. The impact of | |
901 | this compile option is a larger kernel text size of about 2%. | |
346e15be JB |
902 | |
903 | Usage: | |
904 | ||
86151fdf JB |
905 | Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file, |
906 | which is contained in the 'debugfs' filesystem. Thus, the debugfs | |
907 | filesystem must first be mounted before making use of this feature. | |
908 | We refer the control file as: <debugfs>/dynamic_debug/ddebug. This | |
909 | file contains a list of the debug statements that can be enabled. The | |
910 | format for each line of the file is: | |
346e15be | 911 | |
86151fdf | 912 | filename:lineno [module]function flags format |
346e15be | 913 | |
86151fdf JB |
914 | filename : source file of the debug statement |
915 | lineno : line number of the debug statement | |
916 | module : module that contains the debug statement | |
917 | function : function that contains the debug statement | |
918 | flags : 'p' means the line is turned 'on' for printing | |
919 | format : the format used for the debug statement | |
346e15be JB |
920 | |
921 | From a live system: | |
922 | ||
86151fdf JB |
923 | nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug |
924 | # filename:lineno [module]function flags format | |
925 | fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012" | |
926 | fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012" | |
927 | fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012" | |
346e15be | 928 | |
86151fdf | 929 | Example usage: |
346e15be | 930 | |
86151fdf JB |
931 | // enable the message at line 1603 of file svcsock.c |
932 | nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' > | |
933 | <debugfs>/dynamic_debug/ddebug | |
346e15be | 934 | |
86151fdf JB |
935 | // enable all the messages in file svcsock.c |
936 | nullarbor:~ # echo -n 'file svcsock.c +p' > | |
937 | <debugfs>/dynamic_debug/ddebug | |
346e15be | 938 | |
86151fdf JB |
939 | // enable all the messages in the NFS server module |
940 | nullarbor:~ # echo -n 'module nfsd +p' > | |
941 | <debugfs>/dynamic_debug/ddebug | |
346e15be | 942 | |
86151fdf JB |
943 | // enable all 12 messages in the function svc_process() |
944 | nullarbor:~ # echo -n 'func svc_process +p' > | |
945 | <debugfs>/dynamic_debug/ddebug | |
346e15be | 946 | |
86151fdf JB |
947 | // disable all 12 messages in the function svc_process() |
948 | nullarbor:~ # echo -n 'func svc_process -p' > | |
949 | <debugfs>/dynamic_debug/ddebug | |
346e15be | 950 | |
86151fdf | 951 | See Documentation/dynamic-debug-howto.txt for additional information. |
346e15be | 952 | |
5ee00bd4 JR |
953 | config DMA_API_DEBUG |
954 | bool "Enable debugging of DMA-API usage" | |
955 | depends on HAVE_DMA_API_DEBUG | |
956 | help | |
957 | Enable this option to debug the use of the DMA API by device drivers. | |
958 | With this option you will be able to detect common bugs in device | |
959 | drivers like double-freeing of DMA mappings or freeing mappings that | |
960 | were never allocated. | |
961 | This option causes a performance degredation. Use only if you want | |
962 | to debug device drivers. If unsure, say N. | |
346e15be | 963 | |
267c4025 | 964 | source "samples/Kconfig" |
dc7d5527 JW |
965 | |
966 | source "lib/Kconfig.kgdb" |