Root/
1 | |
2 | config PRINTK_TIME |
3 | bool "Show timing information on printks" |
4 | depends on PRINTK |
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 | |
12 | config DEFAULT_MESSAGE_LOGLEVEL |
13 | int "Default message log level (1-7)" |
14 | range 1 7 |
15 | default "4" |
16 | help |
17 | Default log level for printk statements with no specified priority. |
18 | |
19 | This was hard-coded to KERN_WARNING since at least 2.6.10 but folks |
20 | that are auditing their logs closely may want to set it to a lower |
21 | priority. |
22 | |
23 | config ENABLE_WARN_DEPRECATED |
24 | bool "Enable __deprecated logic" |
25 | default y |
26 | help |
27 | Enable the __deprecated logic in the kernel build. |
28 | Disable this to suppress the "warning: 'foo' is deprecated |
29 | (declared at kernel/power/somefile.c:1234)" messages. |
30 | |
31 | config ENABLE_MUST_CHECK |
32 | bool "Enable __must_check logic" |
33 | default y |
34 | help |
35 | Enable the __must_check logic in the kernel build. Disable this to |
36 | suppress the "warning: ignoring return value of 'foo', declared with |
37 | attribute warn_unused_result" messages. |
38 | |
39 | config FRAME_WARN |
40 | int "Warn for stack frames larger than (needs gcc 4.4)" |
41 | range 0 8192 |
42 | default 1024 if !64BIT |
43 | default 2048 if 64BIT |
44 | help |
45 | Tell gcc to warn at build time for stack frames larger than this. |
46 | Setting this too low will cause a lot of warnings. |
47 | Setting it to 0 disables the warning. |
48 | Requires gcc 4.4 |
49 | |
50 | config MAGIC_SYSRQ |
51 | bool "Magic SysRq key" |
52 | depends on !UML |
53 | help |
54 | If you say Y here, you will have some control over the system even |
55 | if the system crashes for example during kernel debugging (e.g., you |
56 | will be able to flush the buffer cache to disk, reboot the system |
57 | immediately or dump some status information). This is accomplished |
58 | by pressing various keys while holding SysRq (Alt+PrintScreen). It |
59 | also works on a serial console (on PC hardware at least), if you |
60 | send a BREAK and then within 5 seconds a command keypress. The |
61 | keys are documented in <file:Documentation/sysrq.txt>. Don't say Y |
62 | unless you really know what this hack does. |
63 | |
64 | config STRIP_ASM_SYMS |
65 | bool "Strip assembler-generated symbols during link" |
66 | default n |
67 | help |
68 | Strip internal assembler-generated symbols during a link (symbols |
69 | that look like '.Lxxx') so they don't pollute the output of |
70 | get_wchan() and suchlike. |
71 | |
72 | config UNUSED_SYMBOLS |
73 | bool "Enable unused/obsolete exported symbols" |
74 | default y if X86 |
75 | help |
76 | Unused but exported symbols make the kernel needlessly bigger. For |
77 | that reason most of these unused exports will soon be removed. This |
78 | option is provided temporarily to provide a transition period in case |
79 | some external kernel module needs one of these symbols anyway. If you |
80 | encounter such a case in your module, consider if you are actually |
81 | using the right API. (rationale: since nobody in the kernel is using |
82 | this in a module, there is a pretty good chance it's actually the |
83 | wrong interface to use). If you really need the symbol, please send a |
84 | mail to the linux kernel mailing list mentioning the symbol and why |
85 | you really need it, and what the merge plan to the mainline kernel for |
86 | your module is. |
87 | |
88 | config DEBUG_FS |
89 | bool "Debug Filesystem" |
90 | help |
91 | debugfs is a virtual file system that kernel developers use to put |
92 | debugging files into. Enable this option to be able to read and |
93 | write to these files. |
94 | |
95 | For detailed documentation on the debugfs API, see |
96 | Documentation/DocBook/filesystems. |
97 | |
98 | If unsure, say N. |
99 | |
100 | config HEADERS_CHECK |
101 | bool "Run 'make headers_check' when building vmlinux" |
102 | depends on !UML |
103 | help |
104 | This option will extract the user-visible kernel headers whenever |
105 | building the kernel, and will run basic sanity checks on them to |
106 | ensure that exported files do not attempt to include files which |
107 | were not exported, etc. |
108 | |
109 | If you're making modifications to header files which are |
110 | relevant for userspace, say 'Y', and check the headers |
111 | exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in |
112 | your build tree), to make sure they're suitable. |
113 | |
114 | config DEBUG_SECTION_MISMATCH |
115 | bool "Enable full Section mismatch analysis" |
116 | help |
117 | The section mismatch analysis checks if there are illegal |
118 | references from one section to another section. |
119 | Linux will during link or during runtime drop some sections |
120 | and any use of code/data previously in these sections will |
121 | most likely result in an oops. |
122 | In the code functions and variables are annotated with |
123 | __init, __devinit etc. (see full list in include/linux/init.h) |
124 | which results in the code/data being placed in specific sections. |
125 | The section mismatch analysis is always done after a full |
126 | kernel build but enabling this option will in addition |
127 | do the following: |
128 | - Add the option -fno-inline-functions-called-once to gcc |
129 | When inlining a function annotated __init in a non-init |
130 | function we would lose the section information and thus |
131 | the analysis would not catch the illegal reference. |
132 | This option tells gcc to inline less but will also |
133 | result in a larger kernel. |
134 | - Run the section mismatch analysis for each module/built-in.o |
135 | When we run the section mismatch analysis on vmlinux.o we |
136 | lose valueble information about where the mismatch was |
137 | introduced. |
138 | Running the analysis for each module/built-in.o file |
139 | will tell where the mismatch happens much closer to the |
140 | source. The drawback is that we will report the same |
141 | mismatch at least twice. |
142 | - Enable verbose reporting from modpost to help solving |
143 | the section mismatches reported. |
144 | |
145 | config DEBUG_KERNEL |
146 | bool "Kernel debugging" |
147 | help |
148 | Say Y here if you are developing drivers or trying to debug and |
149 | identify kernel problems. |
150 | |
151 | config DEBUG_SHIRQ |
152 | bool "Debug shared IRQ handlers" |
153 | depends on DEBUG_KERNEL && GENERIC_HARDIRQS |
154 | help |
155 | Enable this to generate a spurious interrupt as soon as a shared |
156 | interrupt handler is registered, and just before one is deregistered. |
157 | Drivers ought to be able to handle interrupts coming in at those |
158 | points; some don't and need to be caught. |
159 | |
160 | config LOCKUP_DETECTOR |
161 | bool "Detect Hard and Soft Lockups" |
162 | depends on DEBUG_KERNEL && !S390 |
163 | help |
164 | Say Y here to enable the kernel to act as a watchdog to detect |
165 | hard and soft lockups. |
166 | |
167 | Softlockups are bugs that cause the kernel to loop in kernel |
168 | mode for more than 60 seconds, without giving other tasks a |
169 | chance to run. The current stack trace is displayed upon |
170 | detection and the system will stay locked up. |
171 | |
172 | Hardlockups are bugs that cause the CPU to loop in kernel mode |
173 | for more than 60 seconds, without letting other interrupts have a |
174 | chance to run. The current stack trace is displayed upon detection |
175 | and the system will stay locked up. |
176 | |
177 | The overhead should be minimal. A periodic hrtimer runs to |
178 | generate interrupts and kick the watchdog task every 10-12 seconds. |
179 | An NMI is generated every 60 seconds or so to check for hardlockups. |
180 | |
181 | config HARDLOCKUP_DETECTOR |
182 | def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI && \ |
183 | !ARCH_HAS_NMI_WATCHDOG |
184 | |
185 | config BOOTPARAM_HARDLOCKUP_PANIC |
186 | bool "Panic (Reboot) On Hard Lockups" |
187 | depends on LOCKUP_DETECTOR |
188 | help |
189 | Say Y here to enable the kernel to panic on "hard lockups", |
190 | which are bugs that cause the kernel to loop in kernel |
191 | mode with interrupts disabled for more than 60 seconds. |
192 | |
193 | Say N if unsure. |
194 | |
195 | config BOOTPARAM_HARDLOCKUP_PANIC_VALUE |
196 | int |
197 | depends on LOCKUP_DETECTOR |
198 | range 0 1 |
199 | default 0 if !BOOTPARAM_HARDLOCKUP_PANIC |
200 | default 1 if BOOTPARAM_HARDLOCKUP_PANIC |
201 | |
202 | config BOOTPARAM_SOFTLOCKUP_PANIC |
203 | bool "Panic (Reboot) On Soft Lockups" |
204 | depends on LOCKUP_DETECTOR |
205 | help |
206 | Say Y here to enable the kernel to panic on "soft lockups", |
207 | which are bugs that cause the kernel to loop in kernel |
208 | mode for more than 60 seconds, without giving other tasks a |
209 | chance to run. |
210 | |
211 | The panic can be used in combination with panic_timeout, |
212 | to cause the system to reboot automatically after a |
213 | lockup has been detected. This feature is useful for |
214 | high-availability systems that have uptime guarantees and |
215 | where a lockup must be resolved ASAP. |
216 | |
217 | Say N if unsure. |
218 | |
219 | config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE |
220 | int |
221 | depends on LOCKUP_DETECTOR |
222 | range 0 1 |
223 | default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC |
224 | default 1 if BOOTPARAM_SOFTLOCKUP_PANIC |
225 | |
226 | config DETECT_HUNG_TASK |
227 | bool "Detect Hung Tasks" |
228 | depends on DEBUG_KERNEL |
229 | default DETECT_SOFTLOCKUP |
230 | help |
231 | Say Y here to enable the kernel to detect "hung tasks", |
232 | which are bugs that cause the task to be stuck in |
233 | uninterruptible "D" state indefinitiley. |
234 | |
235 | When a hung task is detected, the kernel will print the |
236 | current stack trace (which you should report), but the |
237 | task will stay in uninterruptible state. If lockdep is |
238 | enabled then all held locks will also be reported. This |
239 | feature has negligible overhead. |
240 | |
241 | config BOOTPARAM_HUNG_TASK_PANIC |
242 | bool "Panic (Reboot) On Hung Tasks" |
243 | depends on DETECT_HUNG_TASK |
244 | help |
245 | Say Y here to enable the kernel to panic on "hung tasks", |
246 | which are bugs that cause the kernel to leave a task stuck |
247 | in uninterruptible "D" state. |
248 | |
249 | The panic can be used in combination with panic_timeout, |
250 | to cause the system to reboot automatically after a |
251 | hung task has been detected. This feature is useful for |
252 | high-availability systems that have uptime guarantees and |
253 | where a hung tasks must be resolved ASAP. |
254 | |
255 | Say N if unsure. |
256 | |
257 | config BOOTPARAM_HUNG_TASK_PANIC_VALUE |
258 | int |
259 | depends on DETECT_HUNG_TASK |
260 | range 0 1 |
261 | default 0 if !BOOTPARAM_HUNG_TASK_PANIC |
262 | default 1 if BOOTPARAM_HUNG_TASK_PANIC |
263 | |
264 | config SCHED_DEBUG |
265 | bool "Collect scheduler debugging info" |
266 | depends on DEBUG_KERNEL && PROC_FS |
267 | default y |
268 | help |
269 | If you say Y here, the /proc/sched_debug file will be provided |
270 | that can help debug the scheduler. The runtime overhead of this |
271 | option is minimal. |
272 | |
273 | config SCHEDSTATS |
274 | bool "Collect scheduler statistics" |
275 | depends on DEBUG_KERNEL && PROC_FS |
276 | help |
277 | If you say Y here, additional code will be inserted into the |
278 | scheduler and related routines to collect statistics about |
279 | scheduler behavior and provide them in /proc/schedstat. These |
280 | stats may be useful for both tuning and debugging the scheduler |
281 | If you aren't debugging the scheduler or trying to tune a specific |
282 | application, you can say N to avoid the very slight overhead |
283 | this adds. |
284 | |
285 | config TIMER_STATS |
286 | bool "Collect kernel timers statistics" |
287 | depends on DEBUG_KERNEL && PROC_FS |
288 | help |
289 | If you say Y here, additional code will be inserted into the |
290 | timer routines to collect statistics about kernel timers being |
291 | reprogrammed. The statistics can be read from /proc/timer_stats. |
292 | The statistics collection is started by writing 1 to /proc/timer_stats, |
293 | writing 0 stops it. This feature is useful to collect information |
294 | about timer usage patterns in kernel and userspace. This feature |
295 | is lightweight if enabled in the kernel config but not activated |
296 | (it defaults to deactivated on bootup and will only be activated |
297 | if some application like powertop activates it explicitly). |
298 | |
299 | config DEBUG_OBJECTS |
300 | bool "Debug object operations" |
301 | depends on DEBUG_KERNEL |
302 | help |
303 | If you say Y here, additional code will be inserted into the |
304 | kernel to track the life time of various objects and validate |
305 | the operations on those objects. |
306 | |
307 | config DEBUG_OBJECTS_SELFTEST |
308 | bool "Debug objects selftest" |
309 | depends on DEBUG_OBJECTS |
310 | help |
311 | This enables the selftest of the object debug code. |
312 | |
313 | config DEBUG_OBJECTS_FREE |
314 | bool "Debug objects in freed memory" |
315 | depends on DEBUG_OBJECTS |
316 | help |
317 | This enables checks whether a k/v free operation frees an area |
318 | which contains an object which has not been deactivated |
319 | properly. This can make kmalloc/kfree-intensive workloads |
320 | much slower. |
321 | |
322 | config DEBUG_OBJECTS_TIMERS |
323 | bool "Debug timer objects" |
324 | depends on DEBUG_OBJECTS |
325 | help |
326 | If you say Y here, additional code will be inserted into the |
327 | timer routines to track the life time of timer objects and |
328 | validate the timer operations. |
329 | |
330 | config DEBUG_OBJECTS_WORK |
331 | bool "Debug work objects" |
332 | depends on DEBUG_OBJECTS |
333 | help |
334 | If you say Y here, additional code will be inserted into the |
335 | work queue routines to track the life time of work objects and |
336 | validate the work operations. |
337 | |
338 | config DEBUG_OBJECTS_RCU_HEAD |
339 | bool "Debug RCU callbacks objects" |
340 | depends on DEBUG_OBJECTS && PREEMPT |
341 | help |
342 | Enable this to turn on debugging of RCU list heads (call_rcu() usage). |
343 | |
344 | config DEBUG_OBJECTS_PERCPU_COUNTER |
345 | bool "Debug percpu counter objects" |
346 | depends on DEBUG_OBJECTS |
347 | help |
348 | If you say Y here, additional code will be inserted into the |
349 | percpu counter routines to track the life time of percpu counter |
350 | objects and validate the percpu counter operations. |
351 | |
352 | config DEBUG_OBJECTS_ENABLE_DEFAULT |
353 | int "debug_objects bootup default value (0-1)" |
354 | range 0 1 |
355 | default "1" |
356 | depends on DEBUG_OBJECTS |
357 | help |
358 | Debug objects boot parameter default value |
359 | |
360 | config DEBUG_SLAB |
361 | bool "Debug slab memory allocations" |
362 | depends on DEBUG_KERNEL && SLAB && !KMEMCHECK |
363 | help |
364 | Say Y here to have the kernel do limited verification on memory |
365 | allocation as well as poisoning memory on free to catch use of freed |
366 | memory. This can make kmalloc/kfree-intensive workloads much slower. |
367 | |
368 | config DEBUG_SLAB_LEAK |
369 | bool "Memory leak debugging" |
370 | depends on DEBUG_SLAB |
371 | |
372 | config SLUB_DEBUG_ON |
373 | bool "SLUB debugging on by default" |
374 | depends on SLUB && SLUB_DEBUG && !KMEMCHECK |
375 | default n |
376 | help |
377 | Boot with debugging on by default. SLUB boots by default with |
378 | the runtime debug capabilities switched off. Enabling this is |
379 | equivalent to specifying the "slub_debug" parameter on boot. |
380 | There is no support for more fine grained debug control like |
381 | possible with slub_debug=xxx. SLUB debugging may be switched |
382 | off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying |
383 | "slub_debug=-". |
384 | |
385 | config SLUB_STATS |
386 | default n |
387 | bool "Enable SLUB performance statistics" |
388 | depends on SLUB && SYSFS |
389 | help |
390 | SLUB statistics are useful to debug SLUBs allocation behavior in |
391 | order find ways to optimize the allocator. This should never be |
392 | enabled for production use since keeping statistics slows down |
393 | the allocator by a few percentage points. The slabinfo command |
394 | supports the determination of the most active slabs to figure |
395 | out which slabs are relevant to a particular load. |
396 | Try running: slabinfo -DA |
397 | |
398 | config DEBUG_KMEMLEAK |
399 | bool "Kernel memory leak detector" |
400 | depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \ |
401 | (X86 || ARM || PPC || S390 || SPARC64 || SUPERH || MICROBLAZE || TILE) |
402 | |
403 | select DEBUG_FS if SYSFS |
404 | select STACKTRACE if STACKTRACE_SUPPORT |
405 | select KALLSYMS |
406 | select CRC32 |
407 | help |
408 | Say Y here if you want to enable the memory leak |
409 | detector. The memory allocation/freeing is traced in a way |
410 | similar to the Boehm's conservative garbage collector, the |
411 | difference being that the orphan objects are not freed but |
412 | only shown in /sys/kernel/debug/kmemleak. Enabling this |
413 | feature will introduce an overhead to memory |
414 | allocations. See Documentation/kmemleak.txt for more |
415 | details. |
416 | |
417 | Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances |
418 | of finding leaks due to the slab objects poisoning. |
419 | |
420 | In order to access the kmemleak file, debugfs needs to be |
421 | mounted (usually at /sys/kernel/debug). |
422 | |
423 | config DEBUG_KMEMLEAK_EARLY_LOG_SIZE |
424 | int "Maximum kmemleak early log entries" |
425 | depends on DEBUG_KMEMLEAK |
426 | range 200 40000 |
427 | default 400 |
428 | help |
429 | Kmemleak must track all the memory allocations to avoid |
430 | reporting false positives. Since memory may be allocated or |
431 | freed before kmemleak is initialised, an early log buffer is |
432 | used to store these actions. If kmemleak reports "early log |
433 | buffer exceeded", please increase this value. |
434 | |
435 | config DEBUG_KMEMLEAK_TEST |
436 | tristate "Simple test for the kernel memory leak detector" |
437 | depends on DEBUG_KMEMLEAK && m |
438 | help |
439 | This option enables a module that explicitly leaks memory. |
440 | |
441 | If unsure, say N. |
442 | |
443 | config DEBUG_KMEMLEAK_DEFAULT_OFF |
444 | bool "Default kmemleak to off" |
445 | depends on DEBUG_KMEMLEAK |
446 | help |
447 | Say Y here to disable kmemleak by default. It can then be enabled |
448 | on the command line via kmemleak=on. |
449 | |
450 | config DEBUG_PREEMPT |
451 | bool "Debug preemptible kernel" |
452 | depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT |
453 | default y |
454 | help |
455 | If you say Y here then the kernel will use a debug variant of the |
456 | commonly used smp_processor_id() function and will print warnings |
457 | if kernel code uses it in a preemption-unsafe way. Also, the kernel |
458 | will detect preemption count underflows. |
459 | |
460 | config DEBUG_RT_MUTEXES |
461 | bool "RT Mutex debugging, deadlock detection" |
462 | depends on DEBUG_KERNEL && RT_MUTEXES |
463 | help |
464 | This allows rt mutex semantics violations and rt mutex related |
465 | deadlocks (lockups) to be detected and reported automatically. |
466 | |
467 | config DEBUG_PI_LIST |
468 | bool |
469 | default y |
470 | depends on DEBUG_RT_MUTEXES |
471 | |
472 | config RT_MUTEX_TESTER |
473 | bool "Built-in scriptable tester for rt-mutexes" |
474 | depends on DEBUG_KERNEL && RT_MUTEXES |
475 | help |
476 | This option enables a rt-mutex tester. |
477 | |
478 | config DEBUG_SPINLOCK |
479 | bool "Spinlock and rw-lock debugging: basic checks" |
480 | depends on DEBUG_KERNEL |
481 | help |
482 | Say Y here and build SMP to catch missing spinlock initialization |
483 | and certain other kinds of spinlock errors commonly made. This is |
484 | best used in conjunction with the NMI watchdog so that spinlock |
485 | deadlocks are also debuggable. |
486 | |
487 | config DEBUG_MUTEXES |
488 | bool "Mutex debugging: basic checks" |
489 | depends on DEBUG_KERNEL |
490 | help |
491 | This feature allows mutex semantics violations to be detected and |
492 | reported. |
493 | |
494 | config DEBUG_LOCK_ALLOC |
495 | bool "Lock debugging: detect incorrect freeing of live locks" |
496 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
497 | select DEBUG_SPINLOCK |
498 | select DEBUG_MUTEXES |
499 | select LOCKDEP |
500 | help |
501 | This feature will check whether any held lock (spinlock, rwlock, |
502 | mutex or rwsem) is incorrectly freed by the kernel, via any of the |
503 | memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), |
504 | vfree(), etc.), whether a live lock is incorrectly reinitialized via |
505 | spin_lock_init()/mutex_init()/etc., or whether there is any lock |
506 | held during task exit. |
507 | |
508 | config PROVE_LOCKING |
509 | bool "Lock debugging: prove locking correctness" |
510 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
511 | select LOCKDEP |
512 | select DEBUG_SPINLOCK |
513 | select DEBUG_MUTEXES |
514 | select DEBUG_LOCK_ALLOC |
515 | select TRACE_IRQFLAGS |
516 | default n |
517 | help |
518 | This feature enables the kernel to prove that all locking |
519 | that occurs in the kernel runtime is mathematically |
520 | correct: that under no circumstance could an arbitrary (and |
521 | not yet triggered) combination of observed locking |
522 | sequences (on an arbitrary number of CPUs, running an |
523 | arbitrary number of tasks and interrupt contexts) cause a |
524 | deadlock. |
525 | |
526 | In short, this feature enables the kernel to report locking |
527 | related deadlocks before they actually occur. |
528 | |
529 | The proof does not depend on how hard and complex a |
530 | deadlock scenario would be to trigger: how many |
531 | participant CPUs, tasks and irq-contexts would be needed |
532 | for it to trigger. The proof also does not depend on |
533 | timing: if a race and a resulting deadlock is possible |
534 | theoretically (no matter how unlikely the race scenario |
535 | is), it will be proven so and will immediately be |
536 | reported by the kernel (once the event is observed that |
537 | makes the deadlock theoretically possible). |
538 | |
539 | If a deadlock is impossible (i.e. the locking rules, as |
540 | observed by the kernel, are mathematically correct), the |
541 | kernel reports nothing. |
542 | |
543 | NOTE: this feature can also be enabled for rwlocks, mutexes |
544 | and rwsems - in which case all dependencies between these |
545 | different locking variants are observed and mapped too, and |
546 | the proof of observed correctness is also maintained for an |
547 | arbitrary combination of these separate locking variants. |
548 | |
549 | For more details, see Documentation/lockdep-design.txt. |
550 | |
551 | config PROVE_RCU |
552 | bool "RCU debugging: prove RCU correctness" |
553 | depends on PROVE_LOCKING |
554 | default n |
555 | help |
556 | This feature enables lockdep extensions that check for correct |
557 | use of RCU APIs. This is currently under development. Say Y |
558 | if you want to debug RCU usage or help work on the PROVE_RCU |
559 | feature. |
560 | |
561 | Say N if you are unsure. |
562 | |
563 | config PROVE_RCU_REPEATEDLY |
564 | bool "RCU debugging: don't disable PROVE_RCU on first splat" |
565 | depends on PROVE_RCU |
566 | default n |
567 | help |
568 | By itself, PROVE_RCU will disable checking upon issuing the |
569 | first warning (or "splat"). This feature prevents such |
570 | disabling, allowing multiple RCU-lockdep warnings to be printed |
571 | on a single reboot. |
572 | |
573 | Say Y to allow multiple RCU-lockdep warnings per boot. |
574 | |
575 | Say N if you are unsure. |
576 | |
577 | config SPARSE_RCU_POINTER |
578 | bool "RCU debugging: sparse-based checks for pointer usage" |
579 | default n |
580 | help |
581 | This feature enables the __rcu sparse annotation for |
582 | RCU-protected pointers. This annotation will cause sparse |
583 | to flag any non-RCU used of annotated pointers. This can be |
584 | helpful when debugging RCU usage. Please note that this feature |
585 | is not intended to enforce code cleanliness; it is instead merely |
586 | a debugging aid. |
587 | |
588 | Say Y to make sparse flag questionable use of RCU-protected pointers |
589 | |
590 | Say N if you are unsure. |
591 | |
592 | config LOCKDEP |
593 | bool |
594 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
595 | select STACKTRACE |
596 | select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE |
597 | select KALLSYMS |
598 | select KALLSYMS_ALL |
599 | |
600 | config LOCK_STAT |
601 | bool "Lock usage statistics" |
602 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
603 | select LOCKDEP |
604 | select DEBUG_SPINLOCK |
605 | select DEBUG_MUTEXES |
606 | select DEBUG_LOCK_ALLOC |
607 | default n |
608 | help |
609 | This feature enables tracking lock contention points |
610 | |
611 | For more details, see Documentation/lockstat.txt |
612 | |
613 | This also enables lock events required by "perf lock", |
614 | subcommand of perf. |
615 | If you want to use "perf lock", you also need to turn on |
616 | CONFIG_EVENT_TRACING. |
617 | |
618 | CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. |
619 | (CONFIG_LOCKDEP defines "acquire" and "release" events.) |
620 | |
621 | config DEBUG_LOCKDEP |
622 | bool "Lock dependency engine debugging" |
623 | depends on DEBUG_KERNEL && LOCKDEP |
624 | help |
625 | If you say Y here, the lock dependency engine will do |
626 | additional runtime checks to debug itself, at the price |
627 | of more runtime overhead. |
628 | |
629 | config TRACE_IRQFLAGS |
630 | bool |
631 | help |
632 | Enables hooks to interrupt enabling and disabling for |
633 | either tracing or lock debugging. |
634 | |
635 | config DEBUG_SPINLOCK_SLEEP |
636 | bool "Spinlock debugging: sleep-inside-spinlock checking" |
637 | depends on DEBUG_KERNEL |
638 | help |
639 | If you say Y here, various routines which may sleep will become very |
640 | noisy if they are called with a spinlock held. |
641 | |
642 | config DEBUG_LOCKING_API_SELFTESTS |
643 | bool "Locking API boot-time self-tests" |
644 | depends on DEBUG_KERNEL |
645 | help |
646 | Say Y here if you want the kernel to run a short self-test during |
647 | bootup. The self-test checks whether common types of locking bugs |
648 | are detected by debugging mechanisms or not. (if you disable |
649 | lock debugging then those bugs wont be detected of course.) |
650 | The following locking APIs are covered: spinlocks, rwlocks, |
651 | mutexes and rwsems. |
652 | |
653 | config STACKTRACE |
654 | bool |
655 | depends on STACKTRACE_SUPPORT |
656 | |
657 | config DEBUG_KOBJECT |
658 | bool "kobject debugging" |
659 | depends on DEBUG_KERNEL |
660 | help |
661 | If you say Y here, some extra kobject debugging messages will be sent |
662 | to the syslog. |
663 | |
664 | config DEBUG_HIGHMEM |
665 | bool "Highmem debugging" |
666 | depends on DEBUG_KERNEL && HIGHMEM |
667 | help |
668 | This options enables addition error checking for high memory systems. |
669 | Disable for production systems. |
670 | |
671 | config DEBUG_BUGVERBOSE |
672 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT |
673 | depends on BUG |
674 | depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \ |
675 | FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300 |
676 | default y |
677 | help |
678 | Say Y here to make BUG() panics output the file name and line number |
679 | of the BUG call as well as the EIP and oops trace. This aids |
680 | debugging but costs about 70-100K of memory. |
681 | |
682 | config DEBUG_INFO |
683 | bool "Compile the kernel with debug info" |
684 | depends on DEBUG_KERNEL |
685 | help |
686 | If you say Y here the resulting kernel image will include |
687 | debugging info resulting in a larger kernel image. |
688 | This adds debug symbols to the kernel and modules (gcc -g), and |
689 | is needed if you intend to use kernel crashdump or binary object |
690 | tools like crash, kgdb, LKCD, gdb, etc on the kernel. |
691 | Say Y here only if you plan to debug the kernel. |
692 | |
693 | If unsure, say N. |
694 | |
695 | config DEBUG_INFO_REDUCED |
696 | bool "Reduce debugging information" |
697 | depends on DEBUG_INFO |
698 | help |
699 | If you say Y here gcc is instructed to generate less debugging |
700 | information for structure types. This means that tools that |
701 | need full debugging information (like kgdb or systemtap) won't |
702 | be happy. But if you merely need debugging information to |
703 | resolve line numbers there is no loss. Advantage is that |
704 | build directory object sizes shrink dramatically over a full |
705 | DEBUG_INFO build and compile times are reduced too. |
706 | Only works with newer gcc versions. |
707 | |
708 | config DEBUG_VM |
709 | bool "Debug VM" |
710 | depends on DEBUG_KERNEL |
711 | help |
712 | Enable this to turn on extended checks in the virtual-memory system |
713 | that may impact performance. |
714 | |
715 | If unsure, say N. |
716 | |
717 | config DEBUG_VIRTUAL |
718 | bool "Debug VM translations" |
719 | depends on DEBUG_KERNEL && X86 |
720 | help |
721 | Enable some costly sanity checks in virtual to page code. This can |
722 | catch mistakes with virt_to_page() and friends. |
723 | |
724 | If unsure, say N. |
725 | |
726 | config DEBUG_NOMMU_REGIONS |
727 | bool "Debug the global anon/private NOMMU mapping region tree" |
728 | depends on DEBUG_KERNEL && !MMU |
729 | help |
730 | This option causes the global tree of anonymous and private mapping |
731 | regions to be regularly checked for invalid topology. |
732 | |
733 | config DEBUG_WRITECOUNT |
734 | bool "Debug filesystem writers count" |
735 | depends on DEBUG_KERNEL |
736 | help |
737 | Enable this to catch wrong use of the writers count in struct |
738 | vfsmount. This will increase the size of each file struct by |
739 | 32 bits. |
740 | |
741 | If unsure, say N. |
742 | |
743 | config DEBUG_MEMORY_INIT |
744 | bool "Debug memory initialisation" if EXPERT |
745 | default !EXPERT |
746 | help |
747 | Enable this for additional checks during memory initialisation. |
748 | The sanity checks verify aspects of the VM such as the memory model |
749 | and other information provided by the architecture. Verbose |
750 | information will be printed at KERN_DEBUG loglevel depending |
751 | on the mminit_loglevel= command-line option. |
752 | |
753 | If unsure, say Y |
754 | |
755 | config DEBUG_LIST |
756 | bool "Debug linked list manipulation" |
757 | depends on DEBUG_KERNEL |
758 | help |
759 | Enable this to turn on extended checks in the linked-list |
760 | walking routines. |
761 | |
762 | If unsure, say N. |
763 | |
764 | config TEST_LIST_SORT |
765 | bool "Linked list sorting test" |
766 | depends on DEBUG_KERNEL |
767 | help |
768 | Enable this to turn on 'list_sort()' function test. This test is |
769 | executed only once during system boot, so affects only boot time. |
770 | |
771 | If unsure, say N. |
772 | |
773 | config DEBUG_SG |
774 | bool "Debug SG table operations" |
775 | depends on DEBUG_KERNEL |
776 | help |
777 | Enable this to turn on checks on scatter-gather tables. This can |
778 | help find problems with drivers that do not properly initialize |
779 | their sg tables. |
780 | |
781 | If unsure, say N. |
782 | |
783 | config DEBUG_NOTIFIERS |
784 | bool "Debug notifier call chains" |
785 | depends on DEBUG_KERNEL |
786 | help |
787 | Enable this to turn on sanity checking for notifier call chains. |
788 | This is most useful for kernel developers to make sure that |
789 | modules properly unregister themselves from notifier chains. |
790 | This is a relatively cheap check but if you care about maximum |
791 | performance, say N. |
792 | |
793 | config DEBUG_CREDENTIALS |
794 | bool "Debug credential management" |
795 | depends on DEBUG_KERNEL |
796 | help |
797 | Enable this to turn on some debug checking for credential |
798 | management. The additional code keeps track of the number of |
799 | pointers from task_structs to any given cred struct, and checks to |
800 | see that this number never exceeds the usage count of the cred |
801 | struct. |
802 | |
803 | Furthermore, if SELinux is enabled, this also checks that the |
804 | security pointer in the cred struct is never seen to be invalid. |
805 | |
806 | If unsure, say N. |
807 | |
808 | # |
809 | # Select this config option from the architecture Kconfig, if it |
810 | # it is preferred to always offer frame pointers as a config |
811 | # option on the architecture (regardless of KERNEL_DEBUG): |
812 | # |
813 | config ARCH_WANT_FRAME_POINTERS |
814 | bool |
815 | help |
816 | |
817 | config FRAME_POINTER |
818 | bool "Compile the kernel with frame pointers" |
819 | depends on DEBUG_KERNEL && \ |
820 | (CRIS || M68K || FRV || UML || \ |
821 | AVR32 || SUPERH || BLACKFIN || MN10300) || \ |
822 | ARCH_WANT_FRAME_POINTERS |
823 | default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS |
824 | help |
825 | If you say Y here the resulting kernel image will be slightly |
826 | larger and slower, but it gives very useful debugging information |
827 | in case of kernel bugs. (precise oopses/stacktraces/warnings) |
828 | |
829 | config BOOT_PRINTK_DELAY |
830 | bool "Delay each boot printk message by N milliseconds" |
831 | depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY |
832 | help |
833 | This build option allows you to read kernel boot messages |
834 | by inserting a short delay after each one. The delay is |
835 | specified in milliseconds on the kernel command line, |
836 | using "boot_delay=N". |
837 | |
838 | It is likely that you would also need to use "lpj=M" to preset |
839 | the "loops per jiffie" value. |
840 | See a previous boot log for the "lpj" value to use for your |
841 | system, and then set "lpj=M" before setting "boot_delay=N". |
842 | NOTE: Using this option may adversely affect SMP systems. |
843 | I.e., processors other than the first one may not boot up. |
844 | BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect |
845 | what it believes to be lockup conditions. |
846 | |
847 | config RCU_TORTURE_TEST |
848 | tristate "torture tests for RCU" |
849 | depends on DEBUG_KERNEL |
850 | default n |
851 | help |
852 | This option provides a kernel module that runs torture tests |
853 | on the RCU infrastructure. The kernel module may be built |
854 | after the fact on the running kernel to be tested, if desired. |
855 | |
856 | Say Y here if you want RCU torture tests to be built into |
857 | the kernel. |
858 | Say M if you want the RCU torture tests to build as a module. |
859 | Say N if you are unsure. |
860 | |
861 | config RCU_TORTURE_TEST_RUNNABLE |
862 | bool "torture tests for RCU runnable by default" |
863 | depends on RCU_TORTURE_TEST = y |
864 | default n |
865 | help |
866 | This option provides a way to build the RCU torture tests |
867 | directly into the kernel without them starting up at boot |
868 | time. You can use /proc/sys/kernel/rcutorture_runnable |
869 | to manually override this setting. This /proc file is |
870 | available only when the RCU torture tests have been built |
871 | into the kernel. |
872 | |
873 | Say Y here if you want the RCU torture tests to start during |
874 | boot (you probably don't). |
875 | Say N here if you want the RCU torture tests to start only |
876 | after being manually enabled via /proc. |
877 | |
878 | config RCU_CPU_STALL_DETECTOR |
879 | bool "Check for stalled CPUs delaying RCU grace periods" |
880 | depends on TREE_RCU || TREE_PREEMPT_RCU |
881 | default y |
882 | help |
883 | This option causes RCU to printk information on which |
884 | CPUs are delaying the current grace period, but only when |
885 | the grace period extends for excessive time periods. |
886 | |
887 | Say N if you want to disable such checks. |
888 | |
889 | Say Y if you are unsure. |
890 | |
891 | config RCU_CPU_STALL_TIMEOUT |
892 | int "RCU CPU stall timeout in seconds" |
893 | depends on RCU_CPU_STALL_DETECTOR |
894 | range 3 300 |
895 | default 60 |
896 | help |
897 | If a given RCU grace period extends more than the specified |
898 | number of seconds, a CPU stall warning is printed. If the |
899 | RCU grace period persists, additional CPU stall warnings are |
900 | printed at more widely spaced intervals. |
901 | |
902 | config RCU_CPU_STALL_DETECTOR_RUNNABLE |
903 | bool "RCU CPU stall checking starts automatically at boot" |
904 | depends on RCU_CPU_STALL_DETECTOR |
905 | default y |
906 | help |
907 | If set, start checking for RCU CPU stalls immediately on |
908 | boot. Otherwise, RCU CPU stall checking must be manually |
909 | enabled. |
910 | |
911 | Say Y if you are unsure. |
912 | |
913 | Say N if you wish to suppress RCU CPU stall checking during boot. |
914 | |
915 | config RCU_CPU_STALL_VERBOSE |
916 | bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR" |
917 | depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU |
918 | default y |
919 | help |
920 | This option causes RCU to printk detailed per-task information |
921 | for any tasks that are stalling the current RCU grace period. |
922 | |
923 | Say N if you are unsure. |
924 | |
925 | Say Y if you want to enable such checks. |
926 | |
927 | config KPROBES_SANITY_TEST |
928 | bool "Kprobes sanity tests" |
929 | depends on DEBUG_KERNEL |
930 | depends on KPROBES |
931 | default n |
932 | help |
933 | This option provides for testing basic kprobes functionality on |
934 | boot. A sample kprobe, jprobe and kretprobe are inserted and |
935 | verified for functionality. |
936 | |
937 | Say N if you are unsure. |
938 | |
939 | config BACKTRACE_SELF_TEST |
940 | tristate "Self test for the backtrace code" |
941 | depends on DEBUG_KERNEL |
942 | default n |
943 | help |
944 | This option provides a kernel module that can be used to test |
945 | the kernel stack backtrace code. This option is not useful |
946 | for distributions or general kernels, but only for kernel |
947 | developers working on architecture code. |
948 | |
949 | Note that if you want to also test saved backtraces, you will |
950 | have to enable STACKTRACE as well. |
951 | |
952 | Say N if you are unsure. |
953 | |
954 | config DEBUG_BLOCK_EXT_DEVT |
955 | bool "Force extended block device numbers and spread them" |
956 | depends on DEBUG_KERNEL |
957 | depends on BLOCK |
958 | default n |
959 | help |
960 | BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON |
961 | SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT |
962 | YOU ARE DOING. Distros, please enable this and fix whatever |
963 | is broken. |
964 | |
965 | Conventionally, block device numbers are allocated from |
966 | predetermined contiguous area. However, extended block area |
967 | may introduce non-contiguous block device numbers. This |
968 | option forces most block device numbers to be allocated from |
969 | the extended space and spreads them to discover kernel or |
970 | userland code paths which assume predetermined contiguous |
971 | device number allocation. |
972 | |
973 | Note that turning on this debug option shuffles all the |
974 | device numbers for all IDE and SCSI devices including libata |
975 | ones, so root partition specified using device number |
976 | directly (via rdev or root=MAJ:MIN) won't work anymore. |
977 | Textual device names (root=/dev/sdXn) will continue to work. |
978 | |
979 | Say N if you are unsure. |
980 | |
981 | config DEBUG_FORCE_WEAK_PER_CPU |
982 | bool "Force weak per-cpu definitions" |
983 | depends on DEBUG_KERNEL |
984 | help |
985 | s390 and alpha require percpu variables in modules to be |
986 | defined weak to work around addressing range issue which |
987 | puts the following two restrictions on percpu variable |
988 | definitions. |
989 | |
990 | 1. percpu symbols must be unique whether static or not |
991 | 2. percpu variables can't be defined inside a function |
992 | |
993 | To ensure that generic code follows the above rules, this |
994 | option forces all percpu variables to be defined as weak. |
995 | |
996 | config LKDTM |
997 | tristate "Linux Kernel Dump Test Tool Module" |
998 | depends on DEBUG_FS |
999 | depends on BLOCK |
1000 | default n |
1001 | help |
1002 | This module enables testing of the different dumping mechanisms by |
1003 | inducing system failures at predefined crash points. |
1004 | If you don't need it: say N |
1005 | Choose M here to compile this code as a module. The module will be |
1006 | called lkdtm. |
1007 | |
1008 | Documentation on how to use the module can be found in |
1009 | Documentation/fault-injection/provoke-crashes.txt |
1010 | |
1011 | config CPU_NOTIFIER_ERROR_INJECT |
1012 | tristate "CPU notifier error injection module" |
1013 | depends on HOTPLUG_CPU && DEBUG_KERNEL |
1014 | help |
1015 | This option provides a kernel module that can be used to test |
1016 | the error handling of the cpu notifiers |
1017 | |
1018 | To compile this code as a module, choose M here: the module will |
1019 | be called cpu-notifier-error-inject. |
1020 | |
1021 | If unsure, say N. |
1022 | |
1023 | config FAULT_INJECTION |
1024 | bool "Fault-injection framework" |
1025 | depends on DEBUG_KERNEL |
1026 | help |
1027 | Provide fault-injection framework. |
1028 | For more details, see Documentation/fault-injection/. |
1029 | |
1030 | config FAILSLAB |
1031 | bool "Fault-injection capability for kmalloc" |
1032 | depends on FAULT_INJECTION |
1033 | depends on SLAB || SLUB |
1034 | help |
1035 | Provide fault-injection capability for kmalloc. |
1036 | |
1037 | config FAIL_PAGE_ALLOC |
1038 | bool "Fault-injection capabilitiy for alloc_pages()" |
1039 | depends on FAULT_INJECTION |
1040 | help |
1041 | Provide fault-injection capability for alloc_pages(). |
1042 | |
1043 | config FAIL_MAKE_REQUEST |
1044 | bool "Fault-injection capability for disk IO" |
1045 | depends on FAULT_INJECTION && BLOCK |
1046 | help |
1047 | Provide fault-injection capability for disk IO. |
1048 | |
1049 | config FAIL_IO_TIMEOUT |
1050 | bool "Fault-injection capability for faking disk interrupts" |
1051 | depends on FAULT_INJECTION && BLOCK |
1052 | help |
1053 | Provide fault-injection capability on end IO handling. This |
1054 | will make the block layer "forget" an interrupt as configured, |
1055 | thus exercising the error handling. |
1056 | |
1057 | Only works with drivers that use the generic timeout handling, |
1058 | for others it wont do anything. |
1059 | |
1060 | config FAULT_INJECTION_DEBUG_FS |
1061 | bool "Debugfs entries for fault-injection capabilities" |
1062 | depends on FAULT_INJECTION && SYSFS && DEBUG_FS |
1063 | help |
1064 | Enable configuration of fault-injection capabilities via debugfs. |
1065 | |
1066 | config FAULT_INJECTION_STACKTRACE_FILTER |
1067 | bool "stacktrace filter for fault-injection capabilities" |
1068 | depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT |
1069 | depends on !X86_64 |
1070 | select STACKTRACE |
1071 | select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE |
1072 | help |
1073 | Provide stacktrace filter for fault-injection capabilities |
1074 | |
1075 | config LATENCYTOP |
1076 | bool "Latency measuring infrastructure" |
1077 | depends on HAVE_LATENCYTOP_SUPPORT |
1078 | depends on DEBUG_KERNEL |
1079 | depends on STACKTRACE_SUPPORT |
1080 | depends on PROC_FS |
1081 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE |
1082 | select KALLSYMS |
1083 | select KALLSYMS_ALL |
1084 | select STACKTRACE |
1085 | select SCHEDSTATS |
1086 | select SCHED_DEBUG |
1087 | help |
1088 | Enable this option if you want to use the LatencyTOP tool |
1089 | to find out which userspace is blocking on what kernel operations. |
1090 | |
1091 | config SYSCTL_SYSCALL_CHECK |
1092 | bool "Sysctl checks" |
1093 | depends on SYSCTL |
1094 | ---help--- |
1095 | sys_sysctl uses binary paths that have been found challenging |
1096 | to properly maintain and use. This enables checks that help |
1097 | you to keep things correct. |
1098 | |
1099 | source mm/Kconfig.debug |
1100 | source kernel/trace/Kconfig |
1101 | |
1102 | config PROVIDE_OHCI1394_DMA_INIT |
1103 | bool "Remote debugging over FireWire early on boot" |
1104 | depends on PCI && X86 |
1105 | help |
1106 | If you want to debug problems which hang or crash the kernel early |
1107 | on boot and the crashing machine has a FireWire port, you can use |
1108 | this feature to remotely access the memory of the crashed machine |
1109 | over FireWire. This employs remote DMA as part of the OHCI1394 |
1110 | specification which is now the standard for FireWire controllers. |
1111 | |
1112 | With remote DMA, you can monitor the printk buffer remotely using |
1113 | firescope and access all memory below 4GB using fireproxy from gdb. |
1114 | Even controlling a kernel debugger is possible using remote DMA. |
1115 | |
1116 | Usage: |
1117 | |
1118 | If ohci1394_dma=early is used as boot parameter, it will initialize |
1119 | all OHCI1394 controllers which are found in the PCI config space. |
1120 | |
1121 | As all changes to the FireWire bus such as enabling and disabling |
1122 | devices cause a bus reset and thereby disable remote DMA for all |
1123 | devices, be sure to have the cable plugged and FireWire enabled on |
1124 | the debugging host before booting the debug target for debugging. |
1125 | |
1126 | This code (~1k) is freed after boot. By then, the firewire stack |
1127 | in charge of the OHCI-1394 controllers should be used instead. |
1128 | |
1129 | See Documentation/debugging-via-ohci1394.txt for more information. |
1130 | |
1131 | config FIREWIRE_OHCI_REMOTE_DMA |
1132 | bool "Remote debugging over FireWire with firewire-ohci" |
1133 | depends on FIREWIRE_OHCI |
1134 | help |
1135 | This option lets you use the FireWire bus for remote debugging |
1136 | with help of the firewire-ohci driver. It enables unfiltered |
1137 | remote DMA in firewire-ohci. |
1138 | See Documentation/debugging-via-ohci1394.txt for more information. |
1139 | |
1140 | If unsure, say N. |
1141 | |
1142 | config BUILD_DOCSRC |
1143 | bool "Build targets in Documentation/ tree" |
1144 | depends on HEADERS_CHECK |
1145 | help |
1146 | This option attempts to build objects from the source files in the |
1147 | kernel Documentation/ tree. |
1148 | |
1149 | Say N if you are unsure. |
1150 | |
1151 | config DYNAMIC_DEBUG |
1152 | bool "Enable dynamic printk() support" |
1153 | default n |
1154 | depends on PRINTK |
1155 | depends on DEBUG_FS |
1156 | help |
1157 | |
1158 | Compiles debug level messages into the kernel, which would not |
1159 | otherwise be available at runtime. These messages can then be |
1160 | enabled/disabled based on various levels of scope - per source file, |
1161 | function, module, format string, and line number. This mechanism |
1162 | implicitly enables all pr_debug() and dev_dbg() calls. The impact of |
1163 | this compile option is a larger kernel text size of about 2%. |
1164 | |
1165 | Usage: |
1166 | |
1167 | Dynamic debugging is controlled via the 'dynamic_debug/control' file, |
1168 | which is contained in the 'debugfs' filesystem. Thus, the debugfs |
1169 | filesystem must first be mounted before making use of this feature. |
1170 | We refer the control file as: <debugfs>/dynamic_debug/control. This |
1171 | file contains a list of the debug statements that can be enabled. The |
1172 | format for each line of the file is: |
1173 | |
1174 | filename:lineno [module]function flags format |
1175 | |
1176 | filename : source file of the debug statement |
1177 | lineno : line number of the debug statement |
1178 | module : module that contains the debug statement |
1179 | function : function that contains the debug statement |
1180 | flags : 'p' means the line is turned 'on' for printing |
1181 | format : the format used for the debug statement |
1182 | |
1183 | From a live system: |
1184 | |
1185 | nullarbor:~ # cat <debugfs>/dynamic_debug/control |
1186 | # filename:lineno [module]function flags format |
1187 | fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012" |
1188 | fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012" |
1189 | fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012" |
1190 | |
1191 | Example usage: |
1192 | |
1193 | // enable the message at line 1603 of file svcsock.c |
1194 | nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' > |
1195 | <debugfs>/dynamic_debug/control |
1196 | |
1197 | // enable all the messages in file svcsock.c |
1198 | nullarbor:~ # echo -n 'file svcsock.c +p' > |
1199 | <debugfs>/dynamic_debug/control |
1200 | |
1201 | // enable all the messages in the NFS server module |
1202 | nullarbor:~ # echo -n 'module nfsd +p' > |
1203 | <debugfs>/dynamic_debug/control |
1204 | |
1205 | // enable all 12 messages in the function svc_process() |
1206 | nullarbor:~ # echo -n 'func svc_process +p' > |
1207 | <debugfs>/dynamic_debug/control |
1208 | |
1209 | // disable all 12 messages in the function svc_process() |
1210 | nullarbor:~ # echo -n 'func svc_process -p' > |
1211 | <debugfs>/dynamic_debug/control |
1212 | |
1213 | See Documentation/dynamic-debug-howto.txt for additional information. |
1214 | |
1215 | config DMA_API_DEBUG |
1216 | bool "Enable debugging of DMA-API usage" |
1217 | depends on HAVE_DMA_API_DEBUG |
1218 | help |
1219 | Enable this option to debug the use of the DMA API by device drivers. |
1220 | With this option you will be able to detect common bugs in device |
1221 | drivers like double-freeing of DMA mappings or freeing mappings that |
1222 | were never allocated. |
1223 | This option causes a performance degredation. Use only if you want |
1224 | to debug device drivers. If unsure, say N. |
1225 | |
1226 | config ATOMIC64_SELFTEST |
1227 | bool "Perform an atomic64_t self-test at boot" |
1228 | help |
1229 | Enable this option to test the atomic64_t functions at boot. |
1230 | |
1231 | If unsure, say N. |
1232 | |
1233 | config ASYNC_RAID6_TEST |
1234 | tristate "Self test for hardware accelerated raid6 recovery" |
1235 | depends on ASYNC_RAID6_RECOV |
1236 | select ASYNC_MEMCPY |
1237 | ---help--- |
1238 | This is a one-shot self test that permutes through the |
1239 | recovery of all the possible two disk failure scenarios for a |
1240 | N-disk array. Recovery is performed with the asynchronous |
1241 | raid6 recovery routines, and will optionally use an offload |
1242 | engine if one is available. |
1243 | |
1244 | If unsure, say N. |
1245 | |
1246 | source "samples/Kconfig" |
1247 | |
1248 | source "lib/Kconfig.kgdb" |
1249 | |
1250 | source "lib/Kconfig.kmemcheck" |
1251 | |
1252 | config TEST_KSTRTOX |
1253 | tristate "Test kstrto*() family of functions at runtime" |
1254 |
Branches:
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
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v3.9