Root/
1 | |
2 | config PRINTK_TIME |
3 | bool "Show timing information on printks" |
4 | depends on PRINTK |
5 | help |
6 | Selecting this option causes time stamps of the printk() |
7 | messages to be added to the output of the syslog() system |
8 | call and at the console. |
9 | |
10 | The timestamp is always recorded internally, and exported |
11 | to /dev/kmsg. This flag just specifies if the timestamp should |
12 | be included, not that the timestamp is recorded. |
13 | |
14 | The behavior is also controlled by the kernel command line |
15 | parameter printk.time=1. See Documentation/kernel-parameters.txt |
16 | |
17 | config DEFAULT_MESSAGE_LOGLEVEL |
18 | int "Default message log level (1-7)" |
19 | range 1 7 |
20 | default "4" |
21 | help |
22 | Default log level for printk statements with no specified priority. |
23 | |
24 | This was hard-coded to KERN_WARNING since at least 2.6.10 but folks |
25 | that are auditing their logs closely may want to set it to a lower |
26 | priority. |
27 | |
28 | config ENABLE_WARN_DEPRECATED |
29 | bool "Enable __deprecated logic" |
30 | default y |
31 | help |
32 | Enable the __deprecated logic in the kernel build. |
33 | Disable this to suppress the "warning: 'foo' is deprecated |
34 | (declared at kernel/power/somefile.c:1234)" messages. |
35 | |
36 | config ENABLE_MUST_CHECK |
37 | bool "Enable __must_check logic" |
38 | default y |
39 | help |
40 | Enable the __must_check logic in the kernel build. Disable this to |
41 | suppress the "warning: ignoring return value of 'foo', declared with |
42 | attribute warn_unused_result" messages. |
43 | |
44 | config FRAME_WARN |
45 | int "Warn for stack frames larger than (needs gcc 4.4)" |
46 | range 0 8192 |
47 | default 1024 if !64BIT |
48 | default 2048 if 64BIT |
49 | help |
50 | Tell gcc to warn at build time for stack frames larger than this. |
51 | Setting this too low will cause a lot of warnings. |
52 | Setting it to 0 disables the warning. |
53 | Requires gcc 4.4 |
54 | |
55 | config MAGIC_SYSRQ |
56 | bool "Magic SysRq key" |
57 | depends on !UML |
58 | help |
59 | If you say Y here, you will have some control over the system even |
60 | if the system crashes for example during kernel debugging (e.g., you |
61 | will be able to flush the buffer cache to disk, reboot the system |
62 | immediately or dump some status information). This is accomplished |
63 | by pressing various keys while holding SysRq (Alt+PrintScreen). It |
64 | also works on a serial console (on PC hardware at least), if you |
65 | send a BREAK and then within 5 seconds a command keypress. The |
66 | keys are documented in <file:Documentation/sysrq.txt>. Don't say Y |
67 | unless you really know what this hack does. |
68 | |
69 | config STRIP_ASM_SYMS |
70 | bool "Strip assembler-generated symbols during link" |
71 | default n |
72 | help |
73 | Strip internal assembler-generated symbols during a link (symbols |
74 | that look like '.Lxxx') so they don't pollute the output of |
75 | get_wchan() and suchlike. |
76 | |
77 | config READABLE_ASM |
78 | bool "Generate readable assembler code" |
79 | depends on DEBUG_KERNEL |
80 | help |
81 | Disable some compiler optimizations that tend to generate human unreadable |
82 | assembler output. This may make the kernel slightly slower, but it helps |
83 | to keep kernel developers who have to stare a lot at assembler listings |
84 | sane. |
85 | |
86 | config UNUSED_SYMBOLS |
87 | bool "Enable unused/obsolete exported symbols" |
88 | default y if X86 |
89 | help |
90 | Unused but exported symbols make the kernel needlessly bigger. For |
91 | that reason most of these unused exports will soon be removed. This |
92 | option is provided temporarily to provide a transition period in case |
93 | some external kernel module needs one of these symbols anyway. If you |
94 | encounter such a case in your module, consider if you are actually |
95 | using the right API. (rationale: since nobody in the kernel is using |
96 | this in a module, there is a pretty good chance it's actually the |
97 | wrong interface to use). If you really need the symbol, please send a |
98 | mail to the linux kernel mailing list mentioning the symbol and why |
99 | you really need it, and what the merge plan to the mainline kernel for |
100 | your module is. |
101 | |
102 | config DEBUG_FS |
103 | bool "Debug Filesystem" |
104 | help |
105 | debugfs is a virtual file system that kernel developers use to put |
106 | debugging files into. Enable this option to be able to read and |
107 | write to these files. |
108 | |
109 | For detailed documentation on the debugfs API, see |
110 | Documentation/DocBook/filesystems. |
111 | |
112 | If unsure, say N. |
113 | |
114 | config HEADERS_CHECK |
115 | bool "Run 'make headers_check' when building vmlinux" |
116 | depends on !UML |
117 | help |
118 | This option will extract the user-visible kernel headers whenever |
119 | building the kernel, and will run basic sanity checks on them to |
120 | ensure that exported files do not attempt to include files which |
121 | were not exported, etc. |
122 | |
123 | If you're making modifications to header files which are |
124 | relevant for userspace, say 'Y', and check the headers |
125 | exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in |
126 | your build tree), to make sure they're suitable. |
127 | |
128 | config DEBUG_SECTION_MISMATCH |
129 | bool "Enable full Section mismatch analysis" |
130 | help |
131 | The section mismatch analysis checks if there are illegal |
132 | references from one section to another section. |
133 | During linktime or runtime, some sections are dropped; |
134 | any use of code/data previously in these sections would |
135 | most likely result in an oops. |
136 | In the code, functions and variables are annotated with |
137 | __init, __cpuinit, etc. (see the full list in include/linux/init.h), |
138 | which results in the code/data being placed in specific sections. |
139 | The section mismatch analysis is always performed after a full |
140 | kernel build, and enabling this option causes the following |
141 | additional steps to occur: |
142 | - Add the option -fno-inline-functions-called-once to gcc commands. |
143 | When inlining a function annotated with __init in a non-init |
144 | function, we would lose the section information and thus |
145 | the analysis would not catch the illegal reference. |
146 | This option tells gcc to inline less (but it does result in |
147 | a larger kernel). |
148 | - Run the section mismatch analysis for each module/built-in.o file. |
149 | When we run the section mismatch analysis on vmlinux.o, we |
150 | lose valueble information about where the mismatch was |
151 | introduced. |
152 | Running the analysis for each module/built-in.o file |
153 | tells where the mismatch happens much closer to the |
154 | source. The drawback is that the same mismatch is |
155 | reported at least twice. |
156 | - Enable verbose reporting from modpost in order to help resolve |
157 | the section mismatches that are reported. |
158 | |
159 | config DEBUG_KERNEL |
160 | bool "Kernel debugging" |
161 | help |
162 | Say Y here if you are developing drivers or trying to debug and |
163 | identify kernel problems. |
164 | |
165 | config DEBUG_SHIRQ |
166 | bool "Debug shared IRQ handlers" |
167 | depends on DEBUG_KERNEL && GENERIC_HARDIRQS |
168 | help |
169 | Enable this to generate a spurious interrupt as soon as a shared |
170 | interrupt handler is registered, and just before one is deregistered. |
171 | Drivers ought to be able to handle interrupts coming in at those |
172 | points; some don't and need to be caught. |
173 | |
174 | config LOCKUP_DETECTOR |
175 | bool "Detect Hard and Soft Lockups" |
176 | depends on DEBUG_KERNEL && !S390 |
177 | help |
178 | Say Y here to enable the kernel to act as a watchdog to detect |
179 | hard and soft lockups. |
180 | |
181 | Softlockups are bugs that cause the kernel to loop in kernel |
182 | mode for more than 20 seconds, without giving other tasks a |
183 | chance to run. The current stack trace is displayed upon |
184 | detection and the system will stay locked up. |
185 | |
186 | Hardlockups are bugs that cause the CPU to loop in kernel mode |
187 | for more than 10 seconds, without letting other interrupts have a |
188 | chance to run. The current stack trace is displayed upon detection |
189 | and the system will stay locked up. |
190 | |
191 | The overhead should be minimal. A periodic hrtimer runs to |
192 | generate interrupts and kick the watchdog task every 4 seconds. |
193 | An NMI is generated every 10 seconds or so to check for hardlockups. |
194 | |
195 | The frequency of hrtimer and NMI events and the soft and hard lockup |
196 | thresholds can be controlled through the sysctl watchdog_thresh. |
197 | |
198 | config HARDLOCKUP_DETECTOR |
199 | def_bool y |
200 | depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG |
201 | depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI |
202 | |
203 | config BOOTPARAM_HARDLOCKUP_PANIC |
204 | bool "Panic (Reboot) On Hard Lockups" |
205 | depends on HARDLOCKUP_DETECTOR |
206 | help |
207 | Say Y here to enable the kernel to panic on "hard lockups", |
208 | which are bugs that cause the kernel to loop in kernel |
209 | mode with interrupts disabled for more than 10 seconds (configurable |
210 | using the watchdog_thresh sysctl). |
211 | |
212 | Say N if unsure. |
213 | |
214 | config BOOTPARAM_HARDLOCKUP_PANIC_VALUE |
215 | int |
216 | depends on HARDLOCKUP_DETECTOR |
217 | range 0 1 |
218 | default 0 if !BOOTPARAM_HARDLOCKUP_PANIC |
219 | default 1 if BOOTPARAM_HARDLOCKUP_PANIC |
220 | |
221 | config BOOTPARAM_SOFTLOCKUP_PANIC |
222 | bool "Panic (Reboot) On Soft Lockups" |
223 | depends on LOCKUP_DETECTOR |
224 | help |
225 | Say Y here to enable the kernel to panic on "soft lockups", |
226 | which are bugs that cause the kernel to loop in kernel |
227 | mode for more than 20 seconds (configurable using the watchdog_thresh |
228 | sysctl), without giving other tasks a chance to run. |
229 | |
230 | The panic can be used in combination with panic_timeout, |
231 | to cause the system to reboot automatically after a |
232 | lockup has been detected. This feature is useful for |
233 | high-availability systems that have uptime guarantees and |
234 | where a lockup must be resolved ASAP. |
235 | |
236 | Say N if unsure. |
237 | |
238 | config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE |
239 | int |
240 | depends on LOCKUP_DETECTOR |
241 | range 0 1 |
242 | default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC |
243 | default 1 if BOOTPARAM_SOFTLOCKUP_PANIC |
244 | |
245 | config PANIC_ON_OOPS |
246 | bool "Panic on Oops" |
247 | help |
248 | Say Y here to enable the kernel to panic when it oopses. This |
249 | has the same effect as setting oops=panic on the kernel command |
250 | line. |
251 | |
252 | This feature is useful to ensure that the kernel does not do |
253 | anything erroneous after an oops which could result in data |
254 | corruption or other issues. |
255 | |
256 | Say N if unsure. |
257 | |
258 | config PANIC_ON_OOPS_VALUE |
259 | int |
260 | range 0 1 |
261 | default 0 if !PANIC_ON_OOPS |
262 | default 1 if PANIC_ON_OOPS |
263 | |
264 | config DETECT_HUNG_TASK |
265 | bool "Detect Hung Tasks" |
266 | depends on DEBUG_KERNEL |
267 | default LOCKUP_DETECTOR |
268 | help |
269 | Say Y here to enable the kernel to detect "hung tasks", |
270 | which are bugs that cause the task to be stuck in |
271 | uninterruptible "D" state indefinitiley. |
272 | |
273 | When a hung task is detected, the kernel will print the |
274 | current stack trace (which you should report), but the |
275 | task will stay in uninterruptible state. If lockdep is |
276 | enabled then all held locks will also be reported. This |
277 | feature has negligible overhead. |
278 | |
279 | config DEFAULT_HUNG_TASK_TIMEOUT |
280 | int "Default timeout for hung task detection (in seconds)" |
281 | depends on DETECT_HUNG_TASK |
282 | default 120 |
283 | help |
284 | This option controls the default timeout (in seconds) used |
285 | to determine when a task has become non-responsive and should |
286 | be considered hung. |
287 | |
288 | It can be adjusted at runtime via the kernel.hung_task_timeout_secs |
289 | sysctl or by writing a value to |
290 | /proc/sys/kernel/hung_task_timeout_secs. |
291 | |
292 | A timeout of 0 disables the check. The default is two minutes. |
293 | Keeping the default should be fine in most cases. |
294 | |
295 | config BOOTPARAM_HUNG_TASK_PANIC |
296 | bool "Panic (Reboot) On Hung Tasks" |
297 | depends on DETECT_HUNG_TASK |
298 | help |
299 | Say Y here to enable the kernel to panic on "hung tasks", |
300 | which are bugs that cause the kernel to leave a task stuck |
301 | in uninterruptible "D" state. |
302 | |
303 | The panic can be used in combination with panic_timeout, |
304 | to cause the system to reboot automatically after a |
305 | hung task has been detected. This feature is useful for |
306 | high-availability systems that have uptime guarantees and |
307 | where a hung tasks must be resolved ASAP. |
308 | |
309 | Say N if unsure. |
310 | |
311 | config BOOTPARAM_HUNG_TASK_PANIC_VALUE |
312 | int |
313 | depends on DETECT_HUNG_TASK |
314 | range 0 1 |
315 | default 0 if !BOOTPARAM_HUNG_TASK_PANIC |
316 | default 1 if BOOTPARAM_HUNG_TASK_PANIC |
317 | |
318 | config SCHED_DEBUG |
319 | bool "Collect scheduler debugging info" |
320 | depends on DEBUG_KERNEL && PROC_FS |
321 | default y |
322 | help |
323 | If you say Y here, the /proc/sched_debug file will be provided |
324 | that can help debug the scheduler. The runtime overhead of this |
325 | option is minimal. |
326 | |
327 | config SCHEDSTATS |
328 | bool "Collect scheduler statistics" |
329 | depends on DEBUG_KERNEL && PROC_FS |
330 | help |
331 | If you say Y here, additional code will be inserted into the |
332 | scheduler and related routines to collect statistics about |
333 | scheduler behavior and provide them in /proc/schedstat. These |
334 | stats may be useful for both tuning and debugging the scheduler |
335 | If you aren't debugging the scheduler or trying to tune a specific |
336 | application, you can say N to avoid the very slight overhead |
337 | this adds. |
338 | |
339 | config TIMER_STATS |
340 | bool "Collect kernel timers statistics" |
341 | depends on DEBUG_KERNEL && PROC_FS |
342 | help |
343 | If you say Y here, additional code will be inserted into the |
344 | timer routines to collect statistics about kernel timers being |
345 | reprogrammed. The statistics can be read from /proc/timer_stats. |
346 | The statistics collection is started by writing 1 to /proc/timer_stats, |
347 | writing 0 stops it. This feature is useful to collect information |
348 | about timer usage patterns in kernel and userspace. This feature |
349 | is lightweight if enabled in the kernel config but not activated |
350 | (it defaults to deactivated on bootup and will only be activated |
351 | if some application like powertop activates it explicitly). |
352 | |
353 | config DEBUG_OBJECTS |
354 | bool "Debug object operations" |
355 | depends on DEBUG_KERNEL |
356 | help |
357 | If you say Y here, additional code will be inserted into the |
358 | kernel to track the life time of various objects and validate |
359 | the operations on those objects. |
360 | |
361 | config DEBUG_OBJECTS_SELFTEST |
362 | bool "Debug objects selftest" |
363 | depends on DEBUG_OBJECTS |
364 | help |
365 | This enables the selftest of the object debug code. |
366 | |
367 | config DEBUG_OBJECTS_FREE |
368 | bool "Debug objects in freed memory" |
369 | depends on DEBUG_OBJECTS |
370 | help |
371 | This enables checks whether a k/v free operation frees an area |
372 | which contains an object which has not been deactivated |
373 | properly. This can make kmalloc/kfree-intensive workloads |
374 | much slower. |
375 | |
376 | config DEBUG_OBJECTS_TIMERS |
377 | bool "Debug timer objects" |
378 | depends on DEBUG_OBJECTS |
379 | help |
380 | If you say Y here, additional code will be inserted into the |
381 | timer routines to track the life time of timer objects and |
382 | validate the timer operations. |
383 | |
384 | config DEBUG_OBJECTS_WORK |
385 | bool "Debug work objects" |
386 | depends on DEBUG_OBJECTS |
387 | help |
388 | If you say Y here, additional code will be inserted into the |
389 | work queue routines to track the life time of work objects and |
390 | validate the work operations. |
391 | |
392 | config DEBUG_OBJECTS_RCU_HEAD |
393 | bool "Debug RCU callbacks objects" |
394 | depends on DEBUG_OBJECTS |
395 | help |
396 | Enable this to turn on debugging of RCU list heads (call_rcu() usage). |
397 | |
398 | config DEBUG_OBJECTS_PERCPU_COUNTER |
399 | bool "Debug percpu counter objects" |
400 | depends on DEBUG_OBJECTS |
401 | help |
402 | If you say Y here, additional code will be inserted into the |
403 | percpu counter routines to track the life time of percpu counter |
404 | objects and validate the percpu counter operations. |
405 | |
406 | config DEBUG_OBJECTS_ENABLE_DEFAULT |
407 | int "debug_objects bootup default value (0-1)" |
408 | range 0 1 |
409 | default "1" |
410 | depends on DEBUG_OBJECTS |
411 | help |
412 | Debug objects boot parameter default value |
413 | |
414 | config DEBUG_SLAB |
415 | bool "Debug slab memory allocations" |
416 | depends on DEBUG_KERNEL && SLAB && !KMEMCHECK |
417 | help |
418 | Say Y here to have the kernel do limited verification on memory |
419 | allocation as well as poisoning memory on free to catch use of freed |
420 | memory. This can make kmalloc/kfree-intensive workloads much slower. |
421 | |
422 | config DEBUG_SLAB_LEAK |
423 | bool "Memory leak debugging" |
424 | depends on DEBUG_SLAB |
425 | |
426 | config SLUB_DEBUG_ON |
427 | bool "SLUB debugging on by default" |
428 | depends on SLUB && SLUB_DEBUG && !KMEMCHECK |
429 | default n |
430 | help |
431 | Boot with debugging on by default. SLUB boots by default with |
432 | the runtime debug capabilities switched off. Enabling this is |
433 | equivalent to specifying the "slub_debug" parameter on boot. |
434 | There is no support for more fine grained debug control like |
435 | possible with slub_debug=xxx. SLUB debugging may be switched |
436 | off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying |
437 | "slub_debug=-". |
438 | |
439 | config SLUB_STATS |
440 | default n |
441 | bool "Enable SLUB performance statistics" |
442 | depends on SLUB && SYSFS |
443 | help |
444 | SLUB statistics are useful to debug SLUBs allocation behavior in |
445 | order find ways to optimize the allocator. This should never be |
446 | enabled for production use since keeping statistics slows down |
447 | the allocator by a few percentage points. The slabinfo command |
448 | supports the determination of the most active slabs to figure |
449 | out which slabs are relevant to a particular load. |
450 | Try running: slabinfo -DA |
451 | |
452 | config HAVE_DEBUG_KMEMLEAK |
453 | bool |
454 | |
455 | config DEBUG_KMEMLEAK |
456 | bool "Kernel memory leak detector" |
457 | depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK |
458 | select DEBUG_FS |
459 | select STACKTRACE if STACKTRACE_SUPPORT |
460 | select KALLSYMS |
461 | select CRC32 |
462 | help |
463 | Say Y here if you want to enable the memory leak |
464 | detector. The memory allocation/freeing is traced in a way |
465 | similar to the Boehm's conservative garbage collector, the |
466 | difference being that the orphan objects are not freed but |
467 | only shown in /sys/kernel/debug/kmemleak. Enabling this |
468 | feature will introduce an overhead to memory |
469 | allocations. See Documentation/kmemleak.txt for more |
470 | details. |
471 | |
472 | Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances |
473 | of finding leaks due to the slab objects poisoning. |
474 | |
475 | In order to access the kmemleak file, debugfs needs to be |
476 | mounted (usually at /sys/kernel/debug). |
477 | |
478 | config DEBUG_KMEMLEAK_EARLY_LOG_SIZE |
479 | int "Maximum kmemleak early log entries" |
480 | depends on DEBUG_KMEMLEAK |
481 | range 200 40000 |
482 | default 400 |
483 | help |
484 | Kmemleak must track all the memory allocations to avoid |
485 | reporting false positives. Since memory may be allocated or |
486 | freed before kmemleak is initialised, an early log buffer is |
487 | used to store these actions. If kmemleak reports "early log |
488 | buffer exceeded", please increase this value. |
489 | |
490 | config DEBUG_KMEMLEAK_TEST |
491 | tristate "Simple test for the kernel memory leak detector" |
492 | depends on DEBUG_KMEMLEAK && m |
493 | help |
494 | This option enables a module that explicitly leaks memory. |
495 | |
496 | If unsure, say N. |
497 | |
498 | config DEBUG_KMEMLEAK_DEFAULT_OFF |
499 | bool "Default kmemleak to off" |
500 | depends on DEBUG_KMEMLEAK |
501 | help |
502 | Say Y here to disable kmemleak by default. It can then be enabled |
503 | on the command line via kmemleak=on. |
504 | |
505 | config DEBUG_PREEMPT |
506 | bool "Debug preemptible kernel" |
507 | depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT |
508 | default y |
509 | help |
510 | If you say Y here then the kernel will use a debug variant of the |
511 | commonly used smp_processor_id() function and will print warnings |
512 | if kernel code uses it in a preemption-unsafe way. Also, the kernel |
513 | will detect preemption count underflows. |
514 | |
515 | config DEBUG_RT_MUTEXES |
516 | bool "RT Mutex debugging, deadlock detection" |
517 | depends on DEBUG_KERNEL && RT_MUTEXES |
518 | help |
519 | This allows rt mutex semantics violations and rt mutex related |
520 | deadlocks (lockups) to be detected and reported automatically. |
521 | |
522 | config DEBUG_PI_LIST |
523 | bool |
524 | default y |
525 | depends on DEBUG_RT_MUTEXES |
526 | |
527 | config RT_MUTEX_TESTER |
528 | bool "Built-in scriptable tester for rt-mutexes" |
529 | depends on DEBUG_KERNEL && RT_MUTEXES |
530 | help |
531 | This option enables a rt-mutex tester. |
532 | |
533 | config DEBUG_SPINLOCK |
534 | bool "Spinlock and rw-lock debugging: basic checks" |
535 | depends on DEBUG_KERNEL |
536 | select UNINLINE_SPIN_UNLOCK |
537 | help |
538 | Say Y here and build SMP to catch missing spinlock initialization |
539 | and certain other kinds of spinlock errors commonly made. This is |
540 | best used in conjunction with the NMI watchdog so that spinlock |
541 | deadlocks are also debuggable. |
542 | |
543 | config DEBUG_MUTEXES |
544 | bool "Mutex debugging: basic checks" |
545 | depends on DEBUG_KERNEL |
546 | help |
547 | This feature allows mutex semantics violations to be detected and |
548 | reported. |
549 | |
550 | config DEBUG_LOCK_ALLOC |
551 | bool "Lock debugging: detect incorrect freeing of live locks" |
552 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
553 | select DEBUG_SPINLOCK |
554 | select DEBUG_MUTEXES |
555 | select LOCKDEP |
556 | help |
557 | This feature will check whether any held lock (spinlock, rwlock, |
558 | mutex or rwsem) is incorrectly freed by the kernel, via any of the |
559 | memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), |
560 | vfree(), etc.), whether a live lock is incorrectly reinitialized via |
561 | spin_lock_init()/mutex_init()/etc., or whether there is any lock |
562 | held during task exit. |
563 | |
564 | config PROVE_LOCKING |
565 | bool "Lock debugging: prove locking correctness" |
566 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
567 | select LOCKDEP |
568 | select DEBUG_SPINLOCK |
569 | select DEBUG_MUTEXES |
570 | select DEBUG_LOCK_ALLOC |
571 | select TRACE_IRQFLAGS |
572 | default n |
573 | help |
574 | This feature enables the kernel to prove that all locking |
575 | that occurs in the kernel runtime is mathematically |
576 | correct: that under no circumstance could an arbitrary (and |
577 | not yet triggered) combination of observed locking |
578 | sequences (on an arbitrary number of CPUs, running an |
579 | arbitrary number of tasks and interrupt contexts) cause a |
580 | deadlock. |
581 | |
582 | In short, this feature enables the kernel to report locking |
583 | related deadlocks before they actually occur. |
584 | |
585 | The proof does not depend on how hard and complex a |
586 | deadlock scenario would be to trigger: how many |
587 | participant CPUs, tasks and irq-contexts would be needed |
588 | for it to trigger. The proof also does not depend on |
589 | timing: if a race and a resulting deadlock is possible |
590 | theoretically (no matter how unlikely the race scenario |
591 | is), it will be proven so and will immediately be |
592 | reported by the kernel (once the event is observed that |
593 | makes the deadlock theoretically possible). |
594 | |
595 | If a deadlock is impossible (i.e. the locking rules, as |
596 | observed by the kernel, are mathematically correct), the |
597 | kernel reports nothing. |
598 | |
599 | NOTE: this feature can also be enabled for rwlocks, mutexes |
600 | and rwsems - in which case all dependencies between these |
601 | different locking variants are observed and mapped too, and |
602 | the proof of observed correctness is also maintained for an |
603 | arbitrary combination of these separate locking variants. |
604 | |
605 | For more details, see Documentation/lockdep-design.txt. |
606 | |
607 | config LOCKDEP |
608 | bool |
609 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
610 | select STACKTRACE |
611 | select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE |
612 | select KALLSYMS |
613 | select KALLSYMS_ALL |
614 | |
615 | config LOCK_STAT |
616 | bool "Lock usage statistics" |
617 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
618 | select LOCKDEP |
619 | select DEBUG_SPINLOCK |
620 | select DEBUG_MUTEXES |
621 | select DEBUG_LOCK_ALLOC |
622 | default n |
623 | help |
624 | This feature enables tracking lock contention points |
625 | |
626 | For more details, see Documentation/lockstat.txt |
627 | |
628 | This also enables lock events required by "perf lock", |
629 | subcommand of perf. |
630 | If you want to use "perf lock", you also need to turn on |
631 | CONFIG_EVENT_TRACING. |
632 | |
633 | CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. |
634 | (CONFIG_LOCKDEP defines "acquire" and "release" events.) |
635 | |
636 | config DEBUG_LOCKDEP |
637 | bool "Lock dependency engine debugging" |
638 | depends on DEBUG_KERNEL && LOCKDEP |
639 | help |
640 | If you say Y here, the lock dependency engine will do |
641 | additional runtime checks to debug itself, at the price |
642 | of more runtime overhead. |
643 | |
644 | config TRACE_IRQFLAGS |
645 | bool |
646 | help |
647 | Enables hooks to interrupt enabling and disabling for |
648 | either tracing or lock debugging. |
649 | |
650 | config DEBUG_ATOMIC_SLEEP |
651 | bool "Sleep inside atomic section checking" |
652 | select PREEMPT_COUNT |
653 | depends on DEBUG_KERNEL |
654 | help |
655 | If you say Y here, various routines which may sleep will become very |
656 | noisy if they are called inside atomic sections: when a spinlock is |
657 | held, inside an rcu read side critical section, inside preempt disabled |
658 | sections, inside an interrupt, etc... |
659 | |
660 | config DEBUG_LOCKING_API_SELFTESTS |
661 | bool "Locking API boot-time self-tests" |
662 | depends on DEBUG_KERNEL |
663 | help |
664 | Say Y here if you want the kernel to run a short self-test during |
665 | bootup. The self-test checks whether common types of locking bugs |
666 | are detected by debugging mechanisms or not. (if you disable |
667 | lock debugging then those bugs wont be detected of course.) |
668 | The following locking APIs are covered: spinlocks, rwlocks, |
669 | mutexes and rwsems. |
670 | |
671 | config STACKTRACE |
672 | bool |
673 | depends on STACKTRACE_SUPPORT |
674 | |
675 | config DEBUG_STACK_USAGE |
676 | bool "Stack utilization instrumentation" |
677 | depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG |
678 | help |
679 | Enables the display of the minimum amount of free stack which each |
680 | task has ever had available in the sysrq-T and sysrq-P debug output. |
681 | |
682 | This option will slow down process creation somewhat. |
683 | |
684 | config DEBUG_KOBJECT |
685 | bool "kobject debugging" |
686 | depends on DEBUG_KERNEL |
687 | help |
688 | If you say Y here, some extra kobject debugging messages will be sent |
689 | to the syslog. |
690 | |
691 | config DEBUG_HIGHMEM |
692 | bool "Highmem debugging" |
693 | depends on DEBUG_KERNEL && HIGHMEM |
694 | help |
695 | This options enables addition error checking for high memory systems. |
696 | Disable for production systems. |
697 | |
698 | config HAVE_DEBUG_BUGVERBOSE |
699 | bool |
700 | |
701 | config DEBUG_BUGVERBOSE |
702 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT |
703 | depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE) |
704 | default y |
705 | help |
706 | Say Y here to make BUG() panics output the file name and line number |
707 | of the BUG call as well as the EIP and oops trace. This aids |
708 | debugging but costs about 70-100K of memory. |
709 | |
710 | config DEBUG_INFO |
711 | bool "Compile the kernel with debug info" |
712 | depends on DEBUG_KERNEL |
713 | help |
714 | If you say Y here the resulting kernel image will include |
715 | debugging info resulting in a larger kernel image. |
716 | This adds debug symbols to the kernel and modules (gcc -g), and |
717 | is needed if you intend to use kernel crashdump or binary object |
718 | tools like crash, kgdb, LKCD, gdb, etc on the kernel. |
719 | Say Y here only if you plan to debug the kernel. |
720 | |
721 | If unsure, say N. |
722 | |
723 | config DEBUG_INFO_REDUCED |
724 | bool "Reduce debugging information" |
725 | depends on DEBUG_INFO |
726 | help |
727 | If you say Y here gcc is instructed to generate less debugging |
728 | information for structure types. This means that tools that |
729 | need full debugging information (like kgdb or systemtap) won't |
730 | be happy. But if you merely need debugging information to |
731 | resolve line numbers there is no loss. Advantage is that |
732 | build directory object sizes shrink dramatically over a full |
733 | DEBUG_INFO build and compile times are reduced too. |
734 | Only works with newer gcc versions. |
735 | |
736 | config DEBUG_VM |
737 | bool "Debug VM" |
738 | depends on DEBUG_KERNEL |
739 | help |
740 | Enable this to turn on extended checks in the virtual-memory system |
741 | that may impact performance. |
742 | |
743 | If unsure, say N. |
744 | |
745 | config DEBUG_VM_RB |
746 | bool "Debug VM red-black trees" |
747 | depends on DEBUG_VM |
748 | help |
749 | Enable this to turn on more extended checks in the virtual-memory |
750 | system that may impact performance. |
751 | |
752 | If unsure, say N. |
753 | |
754 | config DEBUG_VIRTUAL |
755 | bool "Debug VM translations" |
756 | depends on DEBUG_KERNEL && X86 |
757 | help |
758 | Enable some costly sanity checks in virtual to page code. This can |
759 | catch mistakes with virt_to_page() and friends. |
760 | |
761 | If unsure, say N. |
762 | |
763 | config DEBUG_NOMMU_REGIONS |
764 | bool "Debug the global anon/private NOMMU mapping region tree" |
765 | depends on DEBUG_KERNEL && !MMU |
766 | help |
767 | This option causes the global tree of anonymous and private mapping |
768 | regions to be regularly checked for invalid topology. |
769 | |
770 | config DEBUG_WRITECOUNT |
771 | bool "Debug filesystem writers count" |
772 | depends on DEBUG_KERNEL |
773 | help |
774 | Enable this to catch wrong use of the writers count in struct |
775 | vfsmount. This will increase the size of each file struct by |
776 | 32 bits. |
777 | |
778 | If unsure, say N. |
779 | |
780 | config DEBUG_MEMORY_INIT |
781 | bool "Debug memory initialisation" if EXPERT |
782 | default !EXPERT |
783 | help |
784 | Enable this for additional checks during memory initialisation. |
785 | The sanity checks verify aspects of the VM such as the memory model |
786 | and other information provided by the architecture. Verbose |
787 | information will be printed at KERN_DEBUG loglevel depending |
788 | on the mminit_loglevel= command-line option. |
789 | |
790 | If unsure, say Y |
791 | |
792 | config DEBUG_LIST |
793 | bool "Debug linked list manipulation" |
794 | depends on DEBUG_KERNEL |
795 | help |
796 | Enable this to turn on extended checks in the linked-list |
797 | walking routines. |
798 | |
799 | If unsure, say N. |
800 | |
801 | config TEST_LIST_SORT |
802 | bool "Linked list sorting test" |
803 | depends on DEBUG_KERNEL |
804 | help |
805 | Enable this to turn on 'list_sort()' function test. This test is |
806 | executed only once during system boot, so affects only boot time. |
807 | |
808 | If unsure, say N. |
809 | |
810 | config DEBUG_SG |
811 | bool "Debug SG table operations" |
812 | depends on DEBUG_KERNEL |
813 | help |
814 | Enable this to turn on checks on scatter-gather tables. This can |
815 | help find problems with drivers that do not properly initialize |
816 | their sg tables. |
817 | |
818 | If unsure, say N. |
819 | |
820 | config DEBUG_NOTIFIERS |
821 | bool "Debug notifier call chains" |
822 | depends on DEBUG_KERNEL |
823 | help |
824 | Enable this to turn on sanity checking for notifier call chains. |
825 | This is most useful for kernel developers to make sure that |
826 | modules properly unregister themselves from notifier chains. |
827 | This is a relatively cheap check but if you care about maximum |
828 | performance, say N. |
829 | |
830 | config DEBUG_CREDENTIALS |
831 | bool "Debug credential management" |
832 | depends on DEBUG_KERNEL |
833 | help |
834 | Enable this to turn on some debug checking for credential |
835 | management. The additional code keeps track of the number of |
836 | pointers from task_structs to any given cred struct, and checks to |
837 | see that this number never exceeds the usage count of the cred |
838 | struct. |
839 | |
840 | Furthermore, if SELinux is enabled, this also checks that the |
841 | security pointer in the cred struct is never seen to be invalid. |
842 | |
843 | If unsure, say N. |
844 | |
845 | # |
846 | # Select this config option from the architecture Kconfig, if it |
847 | # is preferred to always offer frame pointers as a config |
848 | # option on the architecture (regardless of KERNEL_DEBUG): |
849 | # |
850 | config ARCH_WANT_FRAME_POINTERS |
851 | bool |
852 | help |
853 | |
854 | config FRAME_POINTER |
855 | bool "Compile the kernel with frame pointers" |
856 | depends on DEBUG_KERNEL && \ |
857 | (CRIS || M68K || FRV || UML || \ |
858 | AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \ |
859 | ARCH_WANT_FRAME_POINTERS |
860 | default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS |
861 | help |
862 | If you say Y here the resulting kernel image will be slightly |
863 | larger and slower, but it gives very useful debugging information |
864 | in case of kernel bugs. (precise oopses/stacktraces/warnings) |
865 | |
866 | config BOOT_PRINTK_DELAY |
867 | bool "Delay each boot printk message by N milliseconds" |
868 | depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY |
869 | help |
870 | This build option allows you to read kernel boot messages |
871 | by inserting a short delay after each one. The delay is |
872 | specified in milliseconds on the kernel command line, |
873 | using "boot_delay=N". |
874 | |
875 | It is likely that you would also need to use "lpj=M" to preset |
876 | the "loops per jiffie" value. |
877 | See a previous boot log for the "lpj" value to use for your |
878 | system, and then set "lpj=M" before setting "boot_delay=N". |
879 | NOTE: Using this option may adversely affect SMP systems. |
880 | I.e., processors other than the first one may not boot up. |
881 | BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect |
882 | what it believes to be lockup conditions. |
883 | |
884 | menu "RCU Debugging" |
885 | |
886 | config PROVE_RCU |
887 | bool "RCU debugging: prove RCU correctness" |
888 | depends on PROVE_LOCKING |
889 | default n |
890 | help |
891 | This feature enables lockdep extensions that check for correct |
892 | use of RCU APIs. This is currently under development. Say Y |
893 | if you want to debug RCU usage or help work on the PROVE_RCU |
894 | feature. |
895 | |
896 | Say N if you are unsure. |
897 | |
898 | config PROVE_RCU_REPEATEDLY |
899 | bool "RCU debugging: don't disable PROVE_RCU on first splat" |
900 | depends on PROVE_RCU |
901 | default n |
902 | help |
903 | By itself, PROVE_RCU will disable checking upon issuing the |
904 | first warning (or "splat"). This feature prevents such |
905 | disabling, allowing multiple RCU-lockdep warnings to be printed |
906 | on a single reboot. |
907 | |
908 | Say Y to allow multiple RCU-lockdep warnings per boot. |
909 | |
910 | Say N if you are unsure. |
911 | |
912 | config PROVE_RCU_DELAY |
913 | bool "RCU debugging: preemptible RCU race provocation" |
914 | depends on DEBUG_KERNEL && PREEMPT_RCU |
915 | default n |
916 | help |
917 | There is a class of races that involve an unlikely preemption |
918 | of __rcu_read_unlock() just after ->rcu_read_lock_nesting has |
919 | been set to INT_MIN. This feature inserts a delay at that |
920 | point to increase the probability of these races. |
921 | |
922 | Say Y to increase probability of preemption of __rcu_read_unlock(). |
923 | |
924 | Say N if you are unsure. |
925 | |
926 | config SPARSE_RCU_POINTER |
927 | bool "RCU debugging: sparse-based checks for pointer usage" |
928 | default n |
929 | help |
930 | This feature enables the __rcu sparse annotation for |
931 | RCU-protected pointers. This annotation will cause sparse |
932 | to flag any non-RCU used of annotated pointers. This can be |
933 | helpful when debugging RCU usage. Please note that this feature |
934 | is not intended to enforce code cleanliness; it is instead merely |
935 | a debugging aid. |
936 | |
937 | Say Y to make sparse flag questionable use of RCU-protected pointers |
938 | |
939 | Say N if you are unsure. |
940 | |
941 | config RCU_TORTURE_TEST |
942 | tristate "torture tests for RCU" |
943 | depends on DEBUG_KERNEL |
944 | default n |
945 | help |
946 | This option provides a kernel module that runs torture tests |
947 | on the RCU infrastructure. The kernel module may be built |
948 | after the fact on the running kernel to be tested, if desired. |
949 | |
950 | Say Y here if you want RCU torture tests to be built into |
951 | the kernel. |
952 | Say M if you want the RCU torture tests to build as a module. |
953 | Say N if you are unsure. |
954 | |
955 | config RCU_TORTURE_TEST_RUNNABLE |
956 | bool "torture tests for RCU runnable by default" |
957 | depends on RCU_TORTURE_TEST = y |
958 | default n |
959 | help |
960 | This option provides a way to build the RCU torture tests |
961 | directly into the kernel without them starting up at boot |
962 | time. You can use /proc/sys/kernel/rcutorture_runnable |
963 | to manually override this setting. This /proc file is |
964 | available only when the RCU torture tests have been built |
965 | into the kernel. |
966 | |
967 | Say Y here if you want the RCU torture tests to start during |
968 | boot (you probably don't). |
969 | Say N here if you want the RCU torture tests to start only |
970 | after being manually enabled via /proc. |
971 | |
972 | config RCU_CPU_STALL_TIMEOUT |
973 | int "RCU CPU stall timeout in seconds" |
974 | depends on RCU_STALL_COMMON |
975 | range 3 300 |
976 | default 21 |
977 | help |
978 | If a given RCU grace period extends more than the specified |
979 | number of seconds, a CPU stall warning is printed. If the |
980 | RCU grace period persists, additional CPU stall warnings are |
981 | printed at more widely spaced intervals. |
982 | |
983 | config RCU_CPU_STALL_VERBOSE |
984 | bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR" |
985 | depends on TREE_PREEMPT_RCU |
986 | default y |
987 | help |
988 | This option causes RCU to printk detailed per-task information |
989 | for any tasks that are stalling the current RCU grace period. |
990 | |
991 | Say N if you are unsure. |
992 | |
993 | Say Y if you want to enable such checks. |
994 | |
995 | config RCU_CPU_STALL_INFO |
996 | bool "Print additional diagnostics on RCU CPU stall" |
997 | depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL |
998 | default n |
999 | help |
1000 | For each stalled CPU that is aware of the current RCU grace |
1001 | period, print out additional per-CPU diagnostic information |
1002 | regarding scheduling-clock ticks, idle state, and, |
1003 | for RCU_FAST_NO_HZ kernels, idle-entry state. |
1004 | |
1005 | Say N if you are unsure. |
1006 | |
1007 | Say Y if you want to enable such diagnostics. |
1008 | |
1009 | config RCU_TRACE |
1010 | bool "Enable tracing for RCU" |
1011 | depends on DEBUG_KERNEL |
1012 | select TRACE_CLOCK |
1013 | help |
1014 | This option provides tracing in RCU which presents stats |
1015 | in debugfs for debugging RCU implementation. |
1016 | |
1017 | Say Y here if you want to enable RCU tracing |
1018 | Say N if you are unsure. |
1019 | |
1020 | endmenu # "RCU Debugging" |
1021 | |
1022 | config KPROBES_SANITY_TEST |
1023 | bool "Kprobes sanity tests" |
1024 | depends on DEBUG_KERNEL |
1025 | depends on KPROBES |
1026 | default n |
1027 | help |
1028 | This option provides for testing basic kprobes functionality on |
1029 | boot. A sample kprobe, jprobe and kretprobe are inserted and |
1030 | verified for functionality. |
1031 | |
1032 | Say N if you are unsure. |
1033 | |
1034 | config BACKTRACE_SELF_TEST |
1035 | tristate "Self test for the backtrace code" |
1036 | depends on DEBUG_KERNEL |
1037 | default n |
1038 | help |
1039 | This option provides a kernel module that can be used to test |
1040 | the kernel stack backtrace code. This option is not useful |
1041 | for distributions or general kernels, but only for kernel |
1042 | developers working on architecture code. |
1043 | |
1044 | Note that if you want to also test saved backtraces, you will |
1045 | have to enable STACKTRACE as well. |
1046 | |
1047 | Say N if you are unsure. |
1048 | |
1049 | config DEBUG_BLOCK_EXT_DEVT |
1050 | bool "Force extended block device numbers and spread them" |
1051 | depends on DEBUG_KERNEL |
1052 | depends on BLOCK |
1053 | default n |
1054 | help |
1055 | BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON |
1056 | SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT |
1057 | YOU ARE DOING. Distros, please enable this and fix whatever |
1058 | is broken. |
1059 | |
1060 | Conventionally, block device numbers are allocated from |
1061 | predetermined contiguous area. However, extended block area |
1062 | may introduce non-contiguous block device numbers. This |
1063 | option forces most block device numbers to be allocated from |
1064 | the extended space and spreads them to discover kernel or |
1065 | userland code paths which assume predetermined contiguous |
1066 | device number allocation. |
1067 | |
1068 | Note that turning on this debug option shuffles all the |
1069 | device numbers for all IDE and SCSI devices including libata |
1070 | ones, so root partition specified using device number |
1071 | directly (via rdev or root=MAJ:MIN) won't work anymore. |
1072 | Textual device names (root=/dev/sdXn) will continue to work. |
1073 | |
1074 | Say N if you are unsure. |
1075 | |
1076 | config DEBUG_FORCE_WEAK_PER_CPU |
1077 | bool "Force weak per-cpu definitions" |
1078 | depends on DEBUG_KERNEL |
1079 | help |
1080 | s390 and alpha require percpu variables in modules to be |
1081 | defined weak to work around addressing range issue which |
1082 | puts the following two restrictions on percpu variable |
1083 | definitions. |
1084 | |
1085 | 1. percpu symbols must be unique whether static or not |
1086 | 2. percpu variables can't be defined inside a function |
1087 | |
1088 | To ensure that generic code follows the above rules, this |
1089 | option forces all percpu variables to be defined as weak. |
1090 | |
1091 | config DEBUG_PER_CPU_MAPS |
1092 | bool "Debug access to per_cpu maps" |
1093 | depends on DEBUG_KERNEL |
1094 | depends on SMP |
1095 | help |
1096 | Say Y to verify that the per_cpu map being accessed has |
1097 | been set up. This adds a fair amount of code to kernel memory |
1098 | and decreases performance. |
1099 | |
1100 | Say N if unsure. |
1101 | |
1102 | config LKDTM |
1103 | tristate "Linux Kernel Dump Test Tool Module" |
1104 | depends on DEBUG_FS |
1105 | depends on BLOCK |
1106 | default n |
1107 | help |
1108 | This module enables testing of the different dumping mechanisms by |
1109 | inducing system failures at predefined crash points. |
1110 | If you don't need it: say N |
1111 | Choose M here to compile this code as a module. The module will be |
1112 | called lkdtm. |
1113 | |
1114 | Documentation on how to use the module can be found in |
1115 | Documentation/fault-injection/provoke-crashes.txt |
1116 | |
1117 | config NOTIFIER_ERROR_INJECTION |
1118 | tristate "Notifier error injection" |
1119 | depends on DEBUG_KERNEL |
1120 | select DEBUG_FS |
1121 | help |
1122 | This option provides the ability to inject artificial errors to |
1123 | specified notifier chain callbacks. It is useful to test the error |
1124 | handling of notifier call chain failures. |
1125 | |
1126 | Say N if unsure. |
1127 | |
1128 | config CPU_NOTIFIER_ERROR_INJECT |
1129 | tristate "CPU notifier error injection module" |
1130 | depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION |
1131 | help |
1132 | This option provides a kernel module that can be used to test |
1133 | the error handling of the cpu notifiers by injecting artificial |
1134 | errors to CPU notifier chain callbacks. It is controlled through |
1135 | debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu |
1136 | |
1137 | If the notifier call chain should be failed with some events |
1138 | notified, write the error code to "actions/<notifier event>/error". |
1139 | |
1140 | Example: Inject CPU offline error (-1 == -EPERM) |
1141 | |
1142 | # cd /sys/kernel/debug/notifier-error-inject/cpu |
1143 | # echo -1 > actions/CPU_DOWN_PREPARE/error |
1144 | # echo 0 > /sys/devices/system/cpu/cpu1/online |
1145 | bash: echo: write error: Operation not permitted |
1146 | |
1147 | To compile this code as a module, choose M here: the module will |
1148 | be called cpu-notifier-error-inject. |
1149 | |
1150 | If unsure, say N. |
1151 | |
1152 | config PM_NOTIFIER_ERROR_INJECT |
1153 | tristate "PM notifier error injection module" |
1154 | depends on PM && NOTIFIER_ERROR_INJECTION |
1155 | default m if PM_DEBUG |
1156 | help |
1157 | This option provides the ability to inject artificial errors to |
1158 | PM notifier chain callbacks. It is controlled through debugfs |
1159 | interface /sys/kernel/debug/notifier-error-inject/pm |
1160 | |
1161 | If the notifier call chain should be failed with some events |
1162 | notified, write the error code to "actions/<notifier event>/error". |
1163 | |
1164 | Example: Inject PM suspend error (-12 = -ENOMEM) |
1165 | |
1166 | # cd /sys/kernel/debug/notifier-error-inject/pm/ |
1167 | # echo -12 > actions/PM_SUSPEND_PREPARE/error |
1168 | # echo mem > /sys/power/state |
1169 | bash: echo: write error: Cannot allocate memory |
1170 | |
1171 | To compile this code as a module, choose M here: the module will |
1172 | be called pm-notifier-error-inject. |
1173 | |
1174 | If unsure, say N. |
1175 | |
1176 | config MEMORY_NOTIFIER_ERROR_INJECT |
1177 | tristate "Memory hotplug notifier error injection module" |
1178 | depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION |
1179 | help |
1180 | This option provides the ability to inject artificial errors to |
1181 | memory hotplug notifier chain callbacks. It is controlled through |
1182 | debugfs interface under /sys/kernel/debug/notifier-error-inject/memory |
1183 | |
1184 | If the notifier call chain should be failed with some events |
1185 | notified, write the error code to "actions/<notifier event>/error". |
1186 | |
1187 | Example: Inject memory hotplug offline error (-12 == -ENOMEM) |
1188 | |
1189 | # cd /sys/kernel/debug/notifier-error-inject/memory |
1190 | # echo -12 > actions/MEM_GOING_OFFLINE/error |
1191 | # echo offline > /sys/devices/system/memory/memoryXXX/state |
1192 | bash: echo: write error: Cannot allocate memory |
1193 | |
1194 | To compile this code as a module, choose M here: the module will |
1195 | be called pSeries-reconfig-notifier-error-inject. |
1196 | |
1197 | If unsure, say N. |
1198 | |
1199 | config OF_RECONFIG_NOTIFIER_ERROR_INJECT |
1200 | tristate "OF reconfig notifier error injection module" |
1201 | depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION |
1202 | help |
1203 | This option provides the ability to inject artificial errors to |
1204 | OF reconfig notifier chain callbacks. It is controlled |
1205 | through debugfs interface under |
1206 | /sys/kernel/debug/notifier-error-inject/OF-reconfig/ |
1207 | |
1208 | If the notifier call chain should be failed with some events |
1209 | notified, write the error code to "actions/<notifier event>/error". |
1210 | |
1211 | To compile this code as a module, choose M here: the module will |
1212 | be called memory-notifier-error-inject. |
1213 | |
1214 | If unsure, say N. |
1215 | |
1216 | config FAULT_INJECTION |
1217 | bool "Fault-injection framework" |
1218 | depends on DEBUG_KERNEL |
1219 | help |
1220 | Provide fault-injection framework. |
1221 | For more details, see Documentation/fault-injection/. |
1222 | |
1223 | config FAILSLAB |
1224 | bool "Fault-injection capability for kmalloc" |
1225 | depends on FAULT_INJECTION |
1226 | depends on SLAB || SLUB |
1227 | help |
1228 | Provide fault-injection capability for kmalloc. |
1229 | |
1230 | config FAIL_PAGE_ALLOC |
1231 | bool "Fault-injection capabilitiy for alloc_pages()" |
1232 | depends on FAULT_INJECTION |
1233 | help |
1234 | Provide fault-injection capability for alloc_pages(). |
1235 | |
1236 | config FAIL_MAKE_REQUEST |
1237 | bool "Fault-injection capability for disk IO" |
1238 | depends on FAULT_INJECTION && BLOCK |
1239 | help |
1240 | Provide fault-injection capability for disk IO. |
1241 | |
1242 | config FAIL_IO_TIMEOUT |
1243 | bool "Fault-injection capability for faking disk interrupts" |
1244 | depends on FAULT_INJECTION && BLOCK |
1245 | help |
1246 | Provide fault-injection capability on end IO handling. This |
1247 | will make the block layer "forget" an interrupt as configured, |
1248 | thus exercising the error handling. |
1249 | |
1250 | Only works with drivers that use the generic timeout handling, |
1251 | for others it wont do anything. |
1252 | |
1253 | config FAIL_MMC_REQUEST |
1254 | bool "Fault-injection capability for MMC IO" |
1255 | select DEBUG_FS |
1256 | depends on FAULT_INJECTION && MMC |
1257 | help |
1258 | Provide fault-injection capability for MMC IO. |
1259 | This will make the mmc core return data errors. This is |
1260 | useful to test the error handling in the mmc block device |
1261 | and to test how the mmc host driver handles retries from |
1262 | the block device. |
1263 | |
1264 | config FAULT_INJECTION_DEBUG_FS |
1265 | bool "Debugfs entries for fault-injection capabilities" |
1266 | depends on FAULT_INJECTION && SYSFS && DEBUG_FS |
1267 | help |
1268 | Enable configuration of fault-injection capabilities via debugfs. |
1269 | |
1270 | config FAULT_INJECTION_STACKTRACE_FILTER |
1271 | bool "stacktrace filter for fault-injection capabilities" |
1272 | depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT |
1273 | depends on !X86_64 |
1274 | select STACKTRACE |
1275 | select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND |
1276 | help |
1277 | Provide stacktrace filter for fault-injection capabilities |
1278 | |
1279 | config LATENCYTOP |
1280 | bool "Latency measuring infrastructure" |
1281 | depends on HAVE_LATENCYTOP_SUPPORT |
1282 | depends on DEBUG_KERNEL |
1283 | depends on STACKTRACE_SUPPORT |
1284 | depends on PROC_FS |
1285 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND |
1286 | select KALLSYMS |
1287 | select KALLSYMS_ALL |
1288 | select STACKTRACE |
1289 | select SCHEDSTATS |
1290 | select SCHED_DEBUG |
1291 | help |
1292 | Enable this option if you want to use the LatencyTOP tool |
1293 | to find out which userspace is blocking on what kernel operations. |
1294 | |
1295 | source mm/Kconfig.debug |
1296 | source kernel/trace/Kconfig |
1297 | |
1298 | config RBTREE_TEST |
1299 | tristate "Red-Black tree test" |
1300 | depends on m && DEBUG_KERNEL |
1301 | help |
1302 | A benchmark measuring the performance of the rbtree library. |
1303 | Also includes rbtree invariant checks. |
1304 | |
1305 | config INTERVAL_TREE_TEST |
1306 | tristate "Interval tree test" |
1307 | depends on m && DEBUG_KERNEL |
1308 | help |
1309 | A benchmark measuring the performance of the interval tree library |
1310 | |
1311 | config PROVIDE_OHCI1394_DMA_INIT |
1312 | bool "Remote debugging over FireWire early on boot" |
1313 | depends on PCI && X86 |
1314 | help |
1315 | If you want to debug problems which hang or crash the kernel early |
1316 | on boot and the crashing machine has a FireWire port, you can use |
1317 | this feature to remotely access the memory of the crashed machine |
1318 | over FireWire. This employs remote DMA as part of the OHCI1394 |
1319 | specification which is now the standard for FireWire controllers. |
1320 | |
1321 | With remote DMA, you can monitor the printk buffer remotely using |
1322 | firescope and access all memory below 4GB using fireproxy from gdb. |
1323 | Even controlling a kernel debugger is possible using remote DMA. |
1324 | |
1325 | Usage: |
1326 | |
1327 | If ohci1394_dma=early is used as boot parameter, it will initialize |
1328 | all OHCI1394 controllers which are found in the PCI config space. |
1329 | |
1330 | As all changes to the FireWire bus such as enabling and disabling |
1331 | devices cause a bus reset and thereby disable remote DMA for all |
1332 | devices, be sure to have the cable plugged and FireWire enabled on |
1333 | the debugging host before booting the debug target for debugging. |
1334 | |
1335 | This code (~1k) is freed after boot. By then, the firewire stack |
1336 | in charge of the OHCI-1394 controllers should be used instead. |
1337 | |
1338 | See Documentation/debugging-via-ohci1394.txt for more information. |
1339 | |
1340 | config FIREWIRE_OHCI_REMOTE_DMA |
1341 | bool "Remote debugging over FireWire with firewire-ohci" |
1342 | depends on FIREWIRE_OHCI |
1343 | help |
1344 | This option lets you use the FireWire bus for remote debugging |
1345 | with help of the firewire-ohci driver. It enables unfiltered |
1346 | remote DMA in firewire-ohci. |
1347 | See Documentation/debugging-via-ohci1394.txt for more information. |
1348 | |
1349 | If unsure, say N. |
1350 | |
1351 | config BUILD_DOCSRC |
1352 | bool "Build targets in Documentation/ tree" |
1353 | depends on HEADERS_CHECK |
1354 | help |
1355 | This option attempts to build objects from the source files in the |
1356 | kernel Documentation/ tree. |
1357 | |
1358 | Say N if you are unsure. |
1359 | |
1360 | config DYNAMIC_DEBUG |
1361 | bool "Enable dynamic printk() support" |
1362 | default n |
1363 | depends on PRINTK |
1364 | depends on DEBUG_FS |
1365 | help |
1366 | |
1367 | Compiles debug level messages into the kernel, which would not |
1368 | otherwise be available at runtime. These messages can then be |
1369 | enabled/disabled based on various levels of scope - per source file, |
1370 | function, module, format string, and line number. This mechanism |
1371 | implicitly compiles in all pr_debug() and dev_dbg() calls, which |
1372 | enlarges the kernel text size by about 2%. |
1373 | |
1374 | If a source file is compiled with DEBUG flag set, any |
1375 | pr_debug() calls in it are enabled by default, but can be |
1376 | disabled at runtime as below. Note that DEBUG flag is |
1377 | turned on by many CONFIG_*DEBUG* options. |
1378 | |
1379 | Usage: |
1380 | |
1381 | Dynamic debugging is controlled via the 'dynamic_debug/control' file, |
1382 | which is contained in the 'debugfs' filesystem. Thus, the debugfs |
1383 | filesystem must first be mounted before making use of this feature. |
1384 | We refer the control file as: <debugfs>/dynamic_debug/control. This |
1385 | file contains a list of the debug statements that can be enabled. The |
1386 | format for each line of the file is: |
1387 | |
1388 | filename:lineno [module]function flags format |
1389 | |
1390 | filename : source file of the debug statement |
1391 | lineno : line number of the debug statement |
1392 | module : module that contains the debug statement |
1393 | function : function that contains the debug statement |
1394 | flags : '=p' means the line is turned 'on' for printing |
1395 | format : the format used for the debug statement |
1396 | |
1397 | From a live system: |
1398 | |
1399 | nullarbor:~ # cat <debugfs>/dynamic_debug/control |
1400 | # filename:lineno [module]function flags format |
1401 | fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012" |
1402 | fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012" |
1403 | fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012" |
1404 | |
1405 | Example usage: |
1406 | |
1407 | // enable the message at line 1603 of file svcsock.c |
1408 | nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' > |
1409 | <debugfs>/dynamic_debug/control |
1410 | |
1411 | // enable all the messages in file svcsock.c |
1412 | nullarbor:~ # echo -n 'file svcsock.c +p' > |
1413 | <debugfs>/dynamic_debug/control |
1414 | |
1415 | // enable all the messages in the NFS server module |
1416 | nullarbor:~ # echo -n 'module nfsd +p' > |
1417 | <debugfs>/dynamic_debug/control |
1418 | |
1419 | // enable all 12 messages in the function svc_process() |
1420 | nullarbor:~ # echo -n 'func svc_process +p' > |
1421 | <debugfs>/dynamic_debug/control |
1422 | |
1423 | // disable all 12 messages in the function svc_process() |
1424 | nullarbor:~ # echo -n 'func svc_process -p' > |
1425 | <debugfs>/dynamic_debug/control |
1426 | |
1427 | See Documentation/dynamic-debug-howto.txt for additional information. |
1428 | |
1429 | config DMA_API_DEBUG |
1430 | bool "Enable debugging of DMA-API usage" |
1431 | depends on HAVE_DMA_API_DEBUG |
1432 | help |
1433 | Enable this option to debug the use of the DMA API by device drivers. |
1434 | With this option you will be able to detect common bugs in device |
1435 | drivers like double-freeing of DMA mappings or freeing mappings that |
1436 | were never allocated. |
1437 | This option causes a performance degredation. Use only if you want |
1438 | to debug device drivers. If unsure, say N. |
1439 | |
1440 | config ATOMIC64_SELFTEST |
1441 | bool "Perform an atomic64_t self-test at boot" |
1442 | help |
1443 | Enable this option to test the atomic64_t functions at boot. |
1444 | |
1445 | If unsure, say N. |
1446 | |
1447 | config ASYNC_RAID6_TEST |
1448 | tristate "Self test for hardware accelerated raid6 recovery" |
1449 | depends on ASYNC_RAID6_RECOV |
1450 | select ASYNC_MEMCPY |
1451 | ---help--- |
1452 | This is a one-shot self test that permutes through the |
1453 | recovery of all the possible two disk failure scenarios for a |
1454 | N-disk array. Recovery is performed with the asynchronous |
1455 | raid6 recovery routines, and will optionally use an offload |
1456 | engine if one is available. |
1457 | |
1458 | If unsure, say N. |
1459 | |
1460 | source "samples/Kconfig" |
1461 | |
1462 | source "lib/Kconfig.kgdb" |
1463 | |
1464 | source "lib/Kconfig.kmemcheck" |
1465 | |
1466 | config TEST_KSTRTOX |
1467 | tristate "Test kstrto*() family of functions at runtime" |
1468 |
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