Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | |
2 | config PRINTK_TIME | |
3 | bool "Show timing information on printks" | |
d3b8b6e5 | 4 | depends on PRINTK |
1da177e4 LT |
5 | help |
6 | Selecting this option causes timing information to be | |
7 | included in printk output. This allows you to measure | |
8 | the interval between kernel operations, including bootup | |
9 | operations. This is useful for identifying long delays | |
10 | in kernel startup. | |
11 | ||
de488443 JG |
12 | config ENABLE_WARN_DEPRECATED |
13 | bool "Enable __deprecated logic" | |
14 | default y | |
15 | help | |
16 | Enable the __deprecated logic in the kernel build. | |
17 | Disable this to suppress the "warning: 'foo' is deprecated | |
18 | (declared at kernel/power/somefile.c:1234)" messages. | |
19 | ||
cebc04ba AM |
20 | config ENABLE_MUST_CHECK |
21 | bool "Enable __must_check logic" | |
22 | default y | |
23 | help | |
24 | Enable the __must_check logic in the kernel build. Disable this to | |
25 | suppress the "warning: ignoring return value of 'foo', declared with | |
26 | attribute warn_unused_result" messages. | |
1da177e4 | 27 | |
35bb5b1e AK |
28 | config FRAME_WARN |
29 | int "Warn for stack frames larger than (needs gcc 4.4)" | |
30 | range 0 8192 | |
31 | default 1024 if !64BIT | |
32 | default 2048 if 64BIT | |
33 | help | |
34 | Tell gcc to warn at build time for stack frames larger than this. | |
35 | Setting this too low will cause a lot of warnings. | |
36 | Setting it to 0 disables the warning. | |
37 | Requires gcc 4.4 | |
38 | ||
1da177e4 LT |
39 | config MAGIC_SYSRQ |
40 | bool "Magic SysRq key" | |
f346f4b3 | 41 | depends on !UML |
1da177e4 LT |
42 | help |
43 | If you say Y here, you will have some control over the system even | |
44 | if the system crashes for example during kernel debugging (e.g., you | |
45 | will be able to flush the buffer cache to disk, reboot the system | |
46 | immediately or dump some status information). This is accomplished | |
47 | by pressing various keys while holding SysRq (Alt+PrintScreen). It | |
48 | also works on a serial console (on PC hardware at least), if you | |
49 | send a BREAK and then within 5 seconds a command keypress. The | |
50 | keys are documented in <file:Documentation/sysrq.txt>. Don't say Y | |
51 | unless you really know what this hack does. | |
52 | ||
99657c78 RD |
53 | config STRIP_ASM_SYMS |
54 | bool "Strip assembler-generated symbols during link" | |
55 | default n | |
56 | help | |
57 | Strip internal assembler-generated symbols during a link (symbols | |
58 | that look like '.Lxxx') so they don't pollute the output of | |
59 | get_wchan() and suchlike. | |
60 | ||
f71d20e9 AV |
61 | config UNUSED_SYMBOLS |
62 | bool "Enable unused/obsolete exported symbols" | |
63 | default y if X86 | |
64 | help | |
65 | Unused but exported symbols make the kernel needlessly bigger. For | |
66 | that reason most of these unused exports will soon be removed. This | |
67 | option is provided temporarily to provide a transition period in case | |
68 | some external kernel module needs one of these symbols anyway. If you | |
69 | encounter such a case in your module, consider if you are actually | |
70 | using the right API. (rationale: since nobody in the kernel is using | |
71 | this in a module, there is a pretty good chance it's actually the | |
72 | wrong interface to use). If you really need the symbol, please send a | |
73 | mail to the linux kernel mailing list mentioning the symbol and why | |
74 | you really need it, and what the merge plan to the mainline kernel for | |
75 | your module is. | |
76 | ||
bf4735a4 DM |
77 | config DEBUG_FS |
78 | bool "Debug Filesystem" | |
79 | depends on SYSFS | |
80 | help | |
81 | debugfs is a virtual file system that kernel developers use to put | |
82 | debugging files into. Enable this option to be able to read and | |
83 | write to these files. | |
84 | ||
ff543332 RD |
85 | For detailed documentation on the debugfs API, see |
86 | Documentation/DocBook/filesystems. | |
87 | ||
bf4735a4 DM |
88 | If unsure, say N. |
89 | ||
90 | config HEADERS_CHECK | |
91 | bool "Run 'make headers_check' when building vmlinux" | |
92 | depends on !UML | |
93 | help | |
94 | This option will extract the user-visible kernel headers whenever | |
95 | building the kernel, and will run basic sanity checks on them to | |
96 | ensure that exported files do not attempt to include files which | |
97 | were not exported, etc. | |
98 | ||
99 | If you're making modifications to header files which are | |
100 | relevant for userspace, say 'Y', and check the headers | |
101 | exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in | |
102 | your build tree), to make sure they're suitable. | |
103 | ||
91341d4b SR |
104 | config DEBUG_SECTION_MISMATCH |
105 | bool "Enable full Section mismatch analysis" | |
1d53661d MF |
106 | depends on UNDEFINED || (BLACKFIN) |
107 | default y | |
fa2144ba | 108 | # This option is on purpose disabled for now. |
af901ca1 | 109 | # It will be enabled when we are down to a reasonable number |
fa2144ba | 110 | # of section mismatch warnings (< 10 for an allyesconfig build) |
91341d4b SR |
111 | help |
112 | The section mismatch analysis checks if there are illegal | |
113 | references from one section to another section. | |
114 | Linux will during link or during runtime drop some sections | |
115 | and any use of code/data previously in these sections will | |
116 | most likely result in an oops. | |
117 | In the code functions and variables are annotated with | |
118 | __init, __devinit etc. (see full list in include/linux/init.h) | |
d6fbfa4f GU |
119 | which results in the code/data being placed in specific sections. |
120 | The section mismatch analysis is always done after a full | |
121 | kernel build but enabling this option will in addition | |
91341d4b SR |
122 | do the following: |
123 | - Add the option -fno-inline-functions-called-once to gcc | |
124 | When inlining a function annotated __init in a non-init | |
d6fbfa4f | 125 | function we would lose the section information and thus |
91341d4b | 126 | the analysis would not catch the illegal reference. |
d6fbfa4f | 127 | This option tells gcc to inline less but will also |
91341d4b SR |
128 | result in a larger kernel. |
129 | - Run the section mismatch analysis for each module/built-in.o | |
130 | When we run the section mismatch analysis on vmlinux.o we | |
d6fbfa4f | 131 | lose valueble information about where the mismatch was |
91341d4b SR |
132 | introduced. |
133 | Running the analysis for each module/built-in.o file | |
134 | will tell where the mismatch happens much closer to the | |
135 | source. The drawback is that we will report the same | |
136 | mismatch at least twice. | |
588ccd73 SR |
137 | - Enable verbose reporting from modpost to help solving |
138 | the section mismatches reported. | |
91341d4b | 139 | |
f346f4b3 AB |
140 | config DEBUG_KERNEL |
141 | bool "Kernel debugging" | |
142 | help | |
143 | Say Y here if you are developing drivers or trying to debug and | |
144 | identify kernel problems. | |
145 | ||
a304e1b8 DW |
146 | config DEBUG_SHIRQ |
147 | bool "Debug shared IRQ handlers" | |
148 | depends on DEBUG_KERNEL && GENERIC_HARDIRQS | |
149 | help | |
150 | Enable this to generate a spurious interrupt as soon as a shared | |
151 | interrupt handler is registered, and just before one is deregistered. | |
152 | Drivers ought to be able to handle interrupts coming in at those | |
153 | points; some don't and need to be caught. | |
154 | ||
58687acb DZ |
155 | config LOCKUP_DETECTOR |
156 | bool "Detect Hard and Soft Lockups" | |
dea20a3f | 157 | depends on DEBUG_KERNEL && !S390 |
8446f1d3 | 158 | help |
58687acb DZ |
159 | Say Y here to enable the kernel to act as a watchdog to detect |
160 | hard and soft lockups. | |
161 | ||
162 | Softlockups are bugs that cause the kernel to loop in kernel | |
9c44bc03 | 163 | mode for more than 60 seconds, without giving other tasks a |
58687acb DZ |
164 | chance to run. The current stack trace is displayed upon |
165 | detection and the system will stay locked up. | |
8446f1d3 | 166 | |
58687acb DZ |
167 | Hardlockups are bugs that cause the CPU to loop in kernel mode |
168 | for more than 60 seconds, without letting other interrupts have a | |
169 | chance to run. The current stack trace is displayed upon detection | |
170 | and the system will stay locked up. | |
8446f1d3 | 171 | |
58687acb DZ |
172 | The overhead should be minimal. A periodic hrtimer runs to |
173 | generate interrupts and kick the watchdog task every 10-12 seconds. | |
174 | An NMI is generated every 60 seconds or so to check for hardlockups. | |
8446f1d3 | 175 | |
23637d47 FW |
176 | config HARDLOCKUP_DETECTOR |
177 | def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI | |
8446f1d3 | 178 | |
9c44bc03 IM |
179 | config BOOTPARAM_SOFTLOCKUP_PANIC |
180 | bool "Panic (Reboot) On Soft Lockups" | |
89d7ce2a | 181 | depends on LOCKUP_DETECTOR |
9c44bc03 IM |
182 | help |
183 | Say Y here to enable the kernel to panic on "soft lockups", | |
184 | which are bugs that cause the kernel to loop in kernel | |
185 | mode for more than 60 seconds, without giving other tasks a | |
186 | chance to run. | |
187 | ||
188 | The panic can be used in combination with panic_timeout, | |
189 | to cause the system to reboot automatically after a | |
190 | lockup has been detected. This feature is useful for | |
191 | high-availability systems that have uptime guarantees and | |
192 | where a lockup must be resolved ASAP. | |
193 | ||
194 | Say N if unsure. | |
195 | ||
196 | config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE | |
197 | int | |
e16bb1d7 | 198 | depends on LOCKUP_DETECTOR |
9c44bc03 IM |
199 | range 0 1 |
200 | default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC | |
201 | default 1 if BOOTPARAM_SOFTLOCKUP_PANIC | |
202 | ||
e162b39a MSB |
203 | config DETECT_HUNG_TASK |
204 | bool "Detect Hung Tasks" | |
205 | depends on DEBUG_KERNEL | |
77d05632 | 206 | default DETECT_SOFTLOCKUP |
e162b39a MSB |
207 | help |
208 | Say Y here to enable the kernel to detect "hung tasks", | |
209 | which are bugs that cause the task to be stuck in | |
210 | uninterruptible "D" state indefinitiley. | |
211 | ||
212 | When a hung task is detected, the kernel will print the | |
213 | current stack trace (which you should report), but the | |
214 | task will stay in uninterruptible state. If lockdep is | |
215 | enabled then all held locks will also be reported. This | |
216 | feature has negligible overhead. | |
217 | ||
218 | config BOOTPARAM_HUNG_TASK_PANIC | |
219 | bool "Panic (Reboot) On Hung Tasks" | |
220 | depends on DETECT_HUNG_TASK | |
221 | help | |
222 | Say Y here to enable the kernel to panic on "hung tasks", | |
223 | which are bugs that cause the kernel to leave a task stuck | |
224 | in uninterruptible "D" state. | |
225 | ||
226 | The panic can be used in combination with panic_timeout, | |
227 | to cause the system to reboot automatically after a | |
228 | hung task has been detected. This feature is useful for | |
229 | high-availability systems that have uptime guarantees and | |
230 | where a hung tasks must be resolved ASAP. | |
231 | ||
232 | Say N if unsure. | |
233 | ||
234 | config BOOTPARAM_HUNG_TASK_PANIC_VALUE | |
235 | int | |
236 | depends on DETECT_HUNG_TASK | |
237 | range 0 1 | |
238 | default 0 if !BOOTPARAM_HUNG_TASK_PANIC | |
239 | default 1 if BOOTPARAM_HUNG_TASK_PANIC | |
240 | ||
b642b6d3 IM |
241 | config SCHED_DEBUG |
242 | bool "Collect scheduler debugging info" | |
243 | depends on DEBUG_KERNEL && PROC_FS | |
244 | default y | |
245 | help | |
246 | If you say Y here, the /proc/sched_debug file will be provided | |
247 | that can help debug the scheduler. The runtime overhead of this | |
248 | option is minimal. | |
249 | ||
1da177e4 LT |
250 | config SCHEDSTATS |
251 | bool "Collect scheduler statistics" | |
252 | depends on DEBUG_KERNEL && PROC_FS | |
253 | help | |
254 | If you say Y here, additional code will be inserted into the | |
255 | scheduler and related routines to collect statistics about | |
256 | scheduler behavior and provide them in /proc/schedstat. These | |
257 | stats may be useful for both tuning and debugging the scheduler | |
258 | If you aren't debugging the scheduler or trying to tune a specific | |
259 | application, you can say N to avoid the very slight overhead | |
260 | this adds. | |
261 | ||
82f67cd9 IM |
262 | config TIMER_STATS |
263 | bool "Collect kernel timers statistics" | |
264 | depends on DEBUG_KERNEL && PROC_FS | |
265 | help | |
266 | If you say Y here, additional code will be inserted into the | |
267 | timer routines to collect statistics about kernel timers being | |
268 | reprogrammed. The statistics can be read from /proc/timer_stats. | |
269 | The statistics collection is started by writing 1 to /proc/timer_stats, | |
270 | writing 0 stops it. This feature is useful to collect information | |
c1a834dc IM |
271 | about timer usage patterns in kernel and userspace. This feature |
272 | is lightweight if enabled in the kernel config but not activated | |
273 | (it defaults to deactivated on bootup and will only be activated | |
274 | if some application like powertop activates it explicitly). | |
82f67cd9 | 275 | |
3ac7fe5a TG |
276 | config DEBUG_OBJECTS |
277 | bool "Debug object operations" | |
278 | depends on DEBUG_KERNEL | |
279 | help | |
280 | If you say Y here, additional code will be inserted into the | |
281 | kernel to track the life time of various objects and validate | |
282 | the operations on those objects. | |
283 | ||
284 | config DEBUG_OBJECTS_SELFTEST | |
285 | bool "Debug objects selftest" | |
286 | depends on DEBUG_OBJECTS | |
287 | help | |
288 | This enables the selftest of the object debug code. | |
289 | ||
290 | config DEBUG_OBJECTS_FREE | |
291 | bool "Debug objects in freed memory" | |
292 | depends on DEBUG_OBJECTS | |
293 | help | |
294 | This enables checks whether a k/v free operation frees an area | |
295 | which contains an object which has not been deactivated | |
296 | properly. This can make kmalloc/kfree-intensive workloads | |
297 | much slower. | |
298 | ||
c6f3a97f TG |
299 | config DEBUG_OBJECTS_TIMERS |
300 | bool "Debug timer objects" | |
301 | depends on DEBUG_OBJECTS | |
302 | help | |
303 | If you say Y here, additional code will be inserted into the | |
304 | timer routines to track the life time of timer objects and | |
305 | validate the timer operations. | |
306 | ||
dc186ad7 TG |
307 | config DEBUG_OBJECTS_WORK |
308 | bool "Debug work objects" | |
309 | depends on DEBUG_OBJECTS | |
310 | help | |
311 | If you say Y here, additional code will be inserted into the | |
312 | work queue routines to track the life time of work objects and | |
313 | validate the work operations. | |
314 | ||
551d55a9 MD |
315 | config DEBUG_OBJECTS_RCU_HEAD |
316 | bool "Debug RCU callbacks objects" | |
317 | depends on DEBUG_OBJECTS && PREEMPT | |
318 | help | |
319 | Enable this to turn on debugging of RCU list heads (call_rcu() usage). | |
320 | ||
3ae70205 IM |
321 | config DEBUG_OBJECTS_ENABLE_DEFAULT |
322 | int "debug_objects bootup default value (0-1)" | |
323 | range 0 1 | |
324 | default "1" | |
325 | depends on DEBUG_OBJECTS | |
326 | help | |
327 | Debug objects boot parameter default value | |
328 | ||
1da177e4 | 329 | config DEBUG_SLAB |
4a2f0acf | 330 | bool "Debug slab memory allocations" |
7d46d9e6 | 331 | depends on DEBUG_KERNEL && SLAB && !KMEMCHECK |
1da177e4 LT |
332 | help |
333 | Say Y here to have the kernel do limited verification on memory | |
334 | allocation as well as poisoning memory on free to catch use of freed | |
335 | memory. This can make kmalloc/kfree-intensive workloads much slower. | |
336 | ||
871751e2 AV |
337 | config DEBUG_SLAB_LEAK |
338 | bool "Memory leak debugging" | |
339 | depends on DEBUG_SLAB | |
340 | ||
f0630fff CL |
341 | config SLUB_DEBUG_ON |
342 | bool "SLUB debugging on by default" | |
7d46d9e6 | 343 | depends on SLUB && SLUB_DEBUG && !KMEMCHECK |
f0630fff CL |
344 | default n |
345 | help | |
346 | Boot with debugging on by default. SLUB boots by default with | |
347 | the runtime debug capabilities switched off. Enabling this is | |
348 | equivalent to specifying the "slub_debug" parameter on boot. | |
349 | There is no support for more fine grained debug control like | |
350 | possible with slub_debug=xxx. SLUB debugging may be switched | |
351 | off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying | |
352 | "slub_debug=-". | |
353 | ||
8ff12cfc CL |
354 | config SLUB_STATS |
355 | default n | |
356 | bool "Enable SLUB performance statistics" | |
5b06c853 | 357 | depends on SLUB && SLUB_DEBUG && SYSFS |
8ff12cfc CL |
358 | help |
359 | SLUB statistics are useful to debug SLUBs allocation behavior in | |
360 | order find ways to optimize the allocator. This should never be | |
361 | enabled for production use since keeping statistics slows down | |
362 | the allocator by a few percentage points. The slabinfo command | |
363 | supports the determination of the most active slabs to figure | |
364 | out which slabs are relevant to a particular load. | |
365 | Try running: slabinfo -DA | |
366 | ||
3bba00d7 CM |
367 | config DEBUG_KMEMLEAK |
368 | bool "Kernel memory leak detector" | |
dfcc3e6a | 369 | depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \ |
9343af08 | 370 | (X86 || ARM || PPC || S390 || SPARC64 || SUPERH || MICROBLAZE) |
dfcc3e6a | 371 | |
3bba00d7 CM |
372 | select DEBUG_FS if SYSFS |
373 | select STACKTRACE if STACKTRACE_SUPPORT | |
374 | select KALLSYMS | |
b60e26a2 | 375 | select CRC32 |
3bba00d7 CM |
376 | help |
377 | Say Y here if you want to enable the memory leak | |
378 | detector. The memory allocation/freeing is traced in a way | |
379 | similar to the Boehm's conservative garbage collector, the | |
380 | difference being that the orphan objects are not freed but | |
381 | only shown in /sys/kernel/debug/kmemleak. Enabling this | |
382 | feature will introduce an overhead to memory | |
383 | allocations. See Documentation/kmemleak.txt for more | |
384 | details. | |
385 | ||
bf96d1e3 CM |
386 | Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances |
387 | of finding leaks due to the slab objects poisoning. | |
388 | ||
3bba00d7 CM |
389 | In order to access the kmemleak file, debugfs needs to be |
390 | mounted (usually at /sys/kernel/debug). | |
391 | ||
a9d9058a CM |
392 | config DEBUG_KMEMLEAK_EARLY_LOG_SIZE |
393 | int "Maximum kmemleak early log entries" | |
394 | depends on DEBUG_KMEMLEAK | |
dfcc3e6a | 395 | range 200 40000 |
a9d9058a CM |
396 | default 400 |
397 | help | |
398 | Kmemleak must track all the memory allocations to avoid | |
399 | reporting false positives. Since memory may be allocated or | |
400 | freed before kmemleak is initialised, an early log buffer is | |
401 | used to store these actions. If kmemleak reports "early log | |
402 | buffer exceeded", please increase this value. | |
403 | ||
0822ee4a CM |
404 | config DEBUG_KMEMLEAK_TEST |
405 | tristate "Simple test for the kernel memory leak detector" | |
406 | depends on DEBUG_KMEMLEAK | |
407 | help | |
408 | Say Y or M here to build a test for the kernel memory leak | |
409 | detector. This option enables a module that explicitly leaks | |
410 | memory. | |
411 | ||
412 | If unsure, say N. | |
413 | ||
1da177e4 LT |
414 | config DEBUG_PREEMPT |
415 | bool "Debug preemptible kernel" | |
01deab98 | 416 | depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT |
1da177e4 LT |
417 | default y |
418 | help | |
419 | If you say Y here then the kernel will use a debug variant of the | |
420 | commonly used smp_processor_id() function and will print warnings | |
421 | if kernel code uses it in a preemption-unsafe way. Also, the kernel | |
422 | will detect preemption count underflows. | |
423 | ||
e7eebaf6 IM |
424 | config DEBUG_RT_MUTEXES |
425 | bool "RT Mutex debugging, deadlock detection" | |
e7eebaf6 IM |
426 | depends on DEBUG_KERNEL && RT_MUTEXES |
427 | help | |
428 | This allows rt mutex semantics violations and rt mutex related | |
429 | deadlocks (lockups) to be detected and reported automatically. | |
430 | ||
431 | config DEBUG_PI_LIST | |
432 | bool | |
433 | default y | |
434 | depends on DEBUG_RT_MUTEXES | |
435 | ||
61a87122 TG |
436 | config RT_MUTEX_TESTER |
437 | bool "Built-in scriptable tester for rt-mutexes" | |
a1583d3e | 438 | depends on DEBUG_KERNEL && RT_MUTEXES |
61a87122 TG |
439 | help |
440 | This option enables a rt-mutex tester. | |
441 | ||
1da177e4 | 442 | config DEBUG_SPINLOCK |
4d9f34ad | 443 | bool "Spinlock and rw-lock debugging: basic checks" |
1da177e4 LT |
444 | depends on DEBUG_KERNEL |
445 | help | |
446 | Say Y here and build SMP to catch missing spinlock initialization | |
447 | and certain other kinds of spinlock errors commonly made. This is | |
448 | best used in conjunction with the NMI watchdog so that spinlock | |
449 | deadlocks are also debuggable. | |
450 | ||
4d9f34ad IM |
451 | config DEBUG_MUTEXES |
452 | bool "Mutex debugging: basic checks" | |
453 | depends on DEBUG_KERNEL | |
454 | help | |
455 | This feature allows mutex semantics violations to be detected and | |
456 | reported. | |
457 | ||
4d9f34ad IM |
458 | config DEBUG_LOCK_ALLOC |
459 | bool "Lock debugging: detect incorrect freeing of live locks" | |
517e7aa5 | 460 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
461 | select DEBUG_SPINLOCK |
462 | select DEBUG_MUTEXES | |
4d9f34ad IM |
463 | select LOCKDEP |
464 | help | |
465 | This feature will check whether any held lock (spinlock, rwlock, | |
466 | mutex or rwsem) is incorrectly freed by the kernel, via any of the | |
467 | memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), | |
468 | vfree(), etc.), whether a live lock is incorrectly reinitialized via | |
469 | spin_lock_init()/mutex_init()/etc., or whether there is any lock | |
470 | held during task exit. | |
471 | ||
472 | config PROVE_LOCKING | |
473 | bool "Lock debugging: prove locking correctness" | |
517e7aa5 | 474 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
475 | select LOCKDEP |
476 | select DEBUG_SPINLOCK | |
477 | select DEBUG_MUTEXES | |
4d9f34ad IM |
478 | select DEBUG_LOCK_ALLOC |
479 | default n | |
480 | help | |
481 | This feature enables the kernel to prove that all locking | |
482 | that occurs in the kernel runtime is mathematically | |
483 | correct: that under no circumstance could an arbitrary (and | |
484 | not yet triggered) combination of observed locking | |
485 | sequences (on an arbitrary number of CPUs, running an | |
486 | arbitrary number of tasks and interrupt contexts) cause a | |
487 | deadlock. | |
488 | ||
489 | In short, this feature enables the kernel to report locking | |
490 | related deadlocks before they actually occur. | |
491 | ||
492 | The proof does not depend on how hard and complex a | |
493 | deadlock scenario would be to trigger: how many | |
494 | participant CPUs, tasks and irq-contexts would be needed | |
495 | for it to trigger. The proof also does not depend on | |
496 | timing: if a race and a resulting deadlock is possible | |
497 | theoretically (no matter how unlikely the race scenario | |
498 | is), it will be proven so and will immediately be | |
499 | reported by the kernel (once the event is observed that | |
500 | makes the deadlock theoretically possible). | |
501 | ||
502 | If a deadlock is impossible (i.e. the locking rules, as | |
503 | observed by the kernel, are mathematically correct), the | |
504 | kernel reports nothing. | |
505 | ||
506 | NOTE: this feature can also be enabled for rwlocks, mutexes | |
507 | and rwsems - in which case all dependencies between these | |
508 | different locking variants are observed and mapped too, and | |
509 | the proof of observed correctness is also maintained for an | |
510 | arbitrary combination of these separate locking variants. | |
511 | ||
512 | For more details, see Documentation/lockdep-design.txt. | |
513 | ||
632ee200 PM |
514 | config PROVE_RCU |
515 | bool "RCU debugging: prove RCU correctness" | |
516 | depends on PROVE_LOCKING | |
517 | default n | |
518 | help | |
519 | This feature enables lockdep extensions that check for correct | |
520 | use of RCU APIs. This is currently under development. Say Y | |
521 | if you want to debug RCU usage or help work on the PROVE_RCU | |
522 | feature. | |
523 | ||
524 | Say N if you are unsure. | |
525 | ||
2b3fc35f LJ |
526 | config PROVE_RCU_REPEATEDLY |
527 | bool "RCU debugging: don't disable PROVE_RCU on first splat" | |
528 | depends on PROVE_RCU | |
529 | default n | |
530 | help | |
531 | By itself, PROVE_RCU will disable checking upon issuing the | |
532 | first warning (or "splat"). This feature prevents such | |
533 | disabling, allowing multiple RCU-lockdep warnings to be printed | |
534 | on a single reboot. | |
535 | ||
536 | Say N if you are unsure. | |
537 | ||
4d9f34ad IM |
538 | config LOCKDEP |
539 | bool | |
517e7aa5 | 540 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad | 541 | select STACKTRACE |
79aac889 | 542 | select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE |
4d9f34ad IM |
543 | select KALLSYMS |
544 | select KALLSYMS_ALL | |
545 | ||
f20786ff | 546 | config LOCK_STAT |
fdfb870f | 547 | bool "Lock usage statistics" |
f20786ff PZ |
548 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
549 | select LOCKDEP | |
550 | select DEBUG_SPINLOCK | |
551 | select DEBUG_MUTEXES | |
552 | select DEBUG_LOCK_ALLOC | |
553 | default n | |
554 | help | |
555 | This feature enables tracking lock contention points | |
556 | ||
a560aa48 PZ |
557 | For more details, see Documentation/lockstat.txt |
558 | ||
dd8b1cf6 FW |
559 | This also enables lock events required by "perf lock", |
560 | subcommand of perf. | |
561 | If you want to use "perf lock", you also need to turn on | |
562 | CONFIG_EVENT_TRACING. | |
84c6f88f HM |
563 | |
564 | CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. | |
dd8b1cf6 | 565 | (CONFIG_LOCKDEP defines "acquire" and "release" events.) |
84c6f88f | 566 | |
4d9f34ad IM |
567 | config DEBUG_LOCKDEP |
568 | bool "Lock dependency engine debugging" | |
517e7aa5 | 569 | depends on DEBUG_KERNEL && LOCKDEP |
4d9f34ad IM |
570 | help |
571 | If you say Y here, the lock dependency engine will do | |
572 | additional runtime checks to debug itself, at the price | |
573 | of more runtime overhead. | |
574 | ||
575 | config TRACE_IRQFLAGS | |
517e7aa5 | 576 | depends on DEBUG_KERNEL |
4d9f34ad IM |
577 | bool |
578 | default y | |
579 | depends on TRACE_IRQFLAGS_SUPPORT | |
580 | depends on PROVE_LOCKING | |
581 | ||
1da177e4 | 582 | config DEBUG_SPINLOCK_SLEEP |
4d9f34ad | 583 | bool "Spinlock debugging: sleep-inside-spinlock checking" |
1da177e4 LT |
584 | depends on DEBUG_KERNEL |
585 | help | |
586 | If you say Y here, various routines which may sleep will become very | |
587 | noisy if they are called with a spinlock held. | |
588 | ||
cae2ed9a IM |
589 | config DEBUG_LOCKING_API_SELFTESTS |
590 | bool "Locking API boot-time self-tests" | |
591 | depends on DEBUG_KERNEL | |
592 | help | |
593 | Say Y here if you want the kernel to run a short self-test during | |
594 | bootup. The self-test checks whether common types of locking bugs | |
595 | are detected by debugging mechanisms or not. (if you disable | |
596 | lock debugging then those bugs wont be detected of course.) | |
597 | The following locking APIs are covered: spinlocks, rwlocks, | |
598 | mutexes and rwsems. | |
599 | ||
8637c099 IM |
600 | config STACKTRACE |
601 | bool | |
602 | depends on STACKTRACE_SUPPORT | |
603 | ||
1da177e4 LT |
604 | config DEBUG_KOBJECT |
605 | bool "kobject debugging" | |
606 | depends on DEBUG_KERNEL | |
607 | help | |
608 | If you say Y here, some extra kobject debugging messages will be sent | |
609 | to the syslog. | |
610 | ||
611 | config DEBUG_HIGHMEM | |
612 | bool "Highmem debugging" | |
613 | depends on DEBUG_KERNEL && HIGHMEM | |
614 | help | |
615 | This options enables addition error checking for high memory systems. | |
616 | Disable for production systems. | |
617 | ||
618 | config DEBUG_BUGVERBOSE | |
619 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED | |
c8538a7a | 620 | depends on BUG |
b920de1b DH |
621 | depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \ |
622 | FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300 | |
8420e7ef | 623 | default y |
1da177e4 LT |
624 | help |
625 | Say Y here to make BUG() panics output the file name and line number | |
626 | of the BUG call as well as the EIP and oops trace. This aids | |
627 | debugging but costs about 70-100K of memory. | |
628 | ||
629 | config DEBUG_INFO | |
630 | bool "Compile the kernel with debug info" | |
631 | depends on DEBUG_KERNEL | |
632 | help | |
633 | If you say Y here the resulting kernel image will include | |
634 | debugging info resulting in a larger kernel image. | |
b72e53f8 AD |
635 | This adds debug symbols to the kernel and modules (gcc -g), and |
636 | is needed if you intend to use kernel crashdump or binary object | |
637 | tools like crash, kgdb, LKCD, gdb, etc on the kernel. | |
1da177e4 LT |
638 | Say Y here only if you plan to debug the kernel. |
639 | ||
640 | If unsure, say N. | |
641 | ||
d6f4ceb7 AK |
642 | config DEBUG_INFO_REDUCED |
643 | bool "Reduce debugging information" | |
644 | depends on DEBUG_INFO | |
645 | help | |
646 | If you say Y here gcc is instructed to generate less debugging | |
647 | information for structure types. This means that tools that | |
648 | need full debugging information (like kgdb or systemtap) won't | |
649 | be happy. But if you merely need debugging information to | |
650 | resolve line numbers there is no loss. Advantage is that | |
651 | build directory object sizes shrink dramatically over a full | |
652 | DEBUG_INFO build and compile times are reduced too. | |
653 | Only works with newer gcc versions. | |
654 | ||
a241ec65 PM |
655 | config DEBUG_VM |
656 | bool "Debug VM" | |
657 | depends on DEBUG_KERNEL | |
658 | help | |
13e7444b NP |
659 | Enable this to turn on extended checks in the virtual-memory system |
660 | that may impact performance. | |
a241ec65 PM |
661 | |
662 | If unsure, say N. | |
663 | ||
59ea7463 JS |
664 | config DEBUG_VIRTUAL |
665 | bool "Debug VM translations" | |
666 | depends on DEBUG_KERNEL && X86 | |
667 | help | |
668 | Enable some costly sanity checks in virtual to page code. This can | |
669 | catch mistakes with virt_to_page() and friends. | |
670 | ||
671 | If unsure, say N. | |
672 | ||
8feae131 DH |
673 | config DEBUG_NOMMU_REGIONS |
674 | bool "Debug the global anon/private NOMMU mapping region tree" | |
675 | depends on DEBUG_KERNEL && !MMU | |
676 | help | |
677 | This option causes the global tree of anonymous and private mapping | |
678 | regions to be regularly checked for invalid topology. | |
679 | ||
ad775f5a DH |
680 | config DEBUG_WRITECOUNT |
681 | bool "Debug filesystem writers count" | |
682 | depends on DEBUG_KERNEL | |
683 | help | |
684 | Enable this to catch wrong use of the writers count in struct | |
685 | vfsmount. This will increase the size of each file struct by | |
686 | 32 bits. | |
687 | ||
688 | If unsure, say N. | |
689 | ||
6b74ab97 MG |
690 | config DEBUG_MEMORY_INIT |
691 | bool "Debug memory initialisation" if EMBEDDED | |
692 | default !EMBEDDED | |
693 | help | |
694 | Enable this for additional checks during memory initialisation. | |
695 | The sanity checks verify aspects of the VM such as the memory model | |
696 | and other information provided by the architecture. Verbose | |
697 | information will be printed at KERN_DEBUG loglevel depending | |
698 | on the mminit_loglevel= command-line option. | |
699 | ||
700 | If unsure, say Y | |
701 | ||
199a9afc DJ |
702 | config DEBUG_LIST |
703 | bool "Debug linked list manipulation" | |
704 | depends on DEBUG_KERNEL | |
705 | help | |
706 | Enable this to turn on extended checks in the linked-list | |
707 | walking routines. | |
708 | ||
709 | If unsure, say N. | |
710 | ||
d6ec0842 JA |
711 | config DEBUG_SG |
712 | bool "Debug SG table operations" | |
713 | depends on DEBUG_KERNEL | |
714 | help | |
715 | Enable this to turn on checks on scatter-gather tables. This can | |
716 | help find problems with drivers that do not properly initialize | |
717 | their sg tables. | |
718 | ||
719 | If unsure, say N. | |
720 | ||
1b2439db AV |
721 | config DEBUG_NOTIFIERS |
722 | bool "Debug notifier call chains" | |
723 | depends on DEBUG_KERNEL | |
724 | help | |
725 | Enable this to turn on sanity checking for notifier call chains. | |
726 | This is most useful for kernel developers to make sure that | |
727 | modules properly unregister themselves from notifier chains. | |
728 | This is a relatively cheap check but if you care about maximum | |
729 | performance, say N. | |
730 | ||
e0e81739 DH |
731 | config DEBUG_CREDENTIALS |
732 | bool "Debug credential management" | |
733 | depends on DEBUG_KERNEL | |
734 | help | |
735 | Enable this to turn on some debug checking for credential | |
736 | management. The additional code keeps track of the number of | |
737 | pointers from task_structs to any given cred struct, and checks to | |
738 | see that this number never exceeds the usage count of the cred | |
739 | struct. | |
740 | ||
741 | Furthermore, if SELinux is enabled, this also checks that the | |
742 | security pointer in the cred struct is never seen to be invalid. | |
743 | ||
744 | If unsure, say N. | |
745 | ||
64dec40d JM |
746 | # |
747 | # Select this config option from the architecture Kconfig, if it | |
748 | # it is preferred to always offer frame pointers as a config | |
749 | # option on the architecture (regardless of KERNEL_DEBUG): | |
750 | # | |
751 | config ARCH_WANT_FRAME_POINTERS | |
752 | bool | |
753 | help | |
754 | ||
1da177e4 LT |
755 | config FRAME_POINTER |
756 | bool "Compile the kernel with frame pointers" | |
b920de1b | 757 | depends on DEBUG_KERNEL && \ |
75ee034a | 758 | (CRIS || M68K || M68KNOMMU || FRV || UML || \ |
da4276b8 IM |
759 | AVR32 || SUPERH || BLACKFIN || MN10300) || \ |
760 | ARCH_WANT_FRAME_POINTERS | |
761 | default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS | |
762 | help | |
763 | If you say Y here the resulting kernel image will be slightly | |
764 | larger and slower, but it gives very useful debugging information | |
765 | in case of kernel bugs. (precise oopses/stacktraces/warnings) | |
1da177e4 | 766 | |
bfe8df3d RD |
767 | config BOOT_PRINTK_DELAY |
768 | bool "Delay each boot printk message by N milliseconds" | |
769 | depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY | |
770 | help | |
771 | This build option allows you to read kernel boot messages | |
772 | by inserting a short delay after each one. The delay is | |
773 | specified in milliseconds on the kernel command line, | |
774 | using "boot_delay=N". | |
775 | ||
776 | It is likely that you would also need to use "lpj=M" to preset | |
777 | the "loops per jiffie" value. | |
778 | See a previous boot log for the "lpj" value to use for your | |
779 | system, and then set "lpj=M" before setting "boot_delay=N". | |
780 | NOTE: Using this option may adversely affect SMP systems. | |
781 | I.e., processors other than the first one may not boot up. | |
782 | BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect | |
783 | what it believes to be lockup conditions. | |
784 | ||
a241ec65 PM |
785 | config RCU_TORTURE_TEST |
786 | tristate "torture tests for RCU" | |
787 | depends on DEBUG_KERNEL | |
788 | default n | |
789 | help | |
790 | This option provides a kernel module that runs torture tests | |
791 | on the RCU infrastructure. The kernel module may be built | |
792 | after the fact on the running kernel to be tested, if desired. | |
793 | ||
31a72bce PM |
794 | Say Y here if you want RCU torture tests to be built into |
795 | the kernel. | |
a241ec65 PM |
796 | Say M if you want the RCU torture tests to build as a module. |
797 | Say N if you are unsure. | |
8bb31b9d | 798 | |
31a72bce PM |
799 | config RCU_TORTURE_TEST_RUNNABLE |
800 | bool "torture tests for RCU runnable by default" | |
801 | depends on RCU_TORTURE_TEST = y | |
802 | default n | |
803 | help | |
804 | This option provides a way to build the RCU torture tests | |
805 | directly into the kernel without them starting up at boot | |
806 | time. You can use /proc/sys/kernel/rcutorture_runnable | |
807 | to manually override this setting. This /proc file is | |
808 | available only when the RCU torture tests have been built | |
809 | into the kernel. | |
810 | ||
811 | Say Y here if you want the RCU torture tests to start during | |
812 | boot (you probably don't). | |
813 | Say N here if you want the RCU torture tests to start only | |
814 | after being manually enabled via /proc. | |
815 | ||
64db4cff PM |
816 | config RCU_CPU_STALL_DETECTOR |
817 | bool "Check for stalled CPUs delaying RCU grace periods" | |
6b3ef48a | 818 | depends on TREE_RCU || TREE_PREEMPT_RCU |
8bfb2f8e | 819 | default y |
64db4cff PM |
820 | help |
821 | This option causes RCU to printk information on which | |
822 | CPUs are delaying the current grace period, but only when | |
823 | the grace period extends for excessive time periods. | |
67182ae1 | 824 | |
4c54005c | 825 | Say N if you want to disable such checks. |
67182ae1 | 826 | |
4c54005c | 827 | Say Y if you are unsure. |
67182ae1 | 828 | |
1ed509a2 PM |
829 | config RCU_CPU_STALL_VERBOSE |
830 | bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR" | |
831 | depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU | |
55ec936f | 832 | default y |
1ed509a2 PM |
833 | help |
834 | This option causes RCU to printk detailed per-task information | |
835 | for any tasks that are stalling the current RCU grace period. | |
67182ae1 PM |
836 | |
837 | Say N if you are unsure. | |
838 | ||
1ed509a2 PM |
839 | Say Y if you want to enable such checks. |
840 | ||
8c1c9356 AM |
841 | config KPROBES_SANITY_TEST |
842 | bool "Kprobes sanity tests" | |
843 | depends on DEBUG_KERNEL | |
844 | depends on KPROBES | |
845 | default n | |
846 | help | |
847 | This option provides for testing basic kprobes functionality on | |
848 | boot. A sample kprobe, jprobe and kretprobe are inserted and | |
849 | verified for functionality. | |
850 | ||
851 | Say N if you are unsure. | |
852 | ||
6dab2778 AV |
853 | config BACKTRACE_SELF_TEST |
854 | tristate "Self test for the backtrace code" | |
855 | depends on DEBUG_KERNEL | |
856 | default n | |
857 | help | |
858 | This option provides a kernel module that can be used to test | |
859 | the kernel stack backtrace code. This option is not useful | |
860 | for distributions or general kernels, but only for kernel | |
861 | developers working on architecture code. | |
862 | ||
ad118c54 VN |
863 | Note that if you want to also test saved backtraces, you will |
864 | have to enable STACKTRACE as well. | |
865 | ||
6dab2778 AV |
866 | Say N if you are unsure. |
867 | ||
870d6656 TH |
868 | config DEBUG_BLOCK_EXT_DEVT |
869 | bool "Force extended block device numbers and spread them" | |
870 | depends on DEBUG_KERNEL | |
871 | depends on BLOCK | |
759f8ca3 | 872 | default n |
870d6656 | 873 | help |
0e11e342 TH |
874 | BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON |
875 | SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT | |
876 | YOU ARE DOING. Distros, please enable this and fix whatever | |
877 | is broken. | |
878 | ||
870d6656 TH |
879 | Conventionally, block device numbers are allocated from |
880 | predetermined contiguous area. However, extended block area | |
881 | may introduce non-contiguous block device numbers. This | |
882 | option forces most block device numbers to be allocated from | |
883 | the extended space and spreads them to discover kernel or | |
884 | userland code paths which assume predetermined contiguous | |
885 | device number allocation. | |
886 | ||
55dc7db7 TH |
887 | Note that turning on this debug option shuffles all the |
888 | device numbers for all IDE and SCSI devices including libata | |
889 | ones, so root partition specified using device number | |
890 | directly (via rdev or root=MAJ:MIN) won't work anymore. | |
891 | Textual device names (root=/dev/sdXn) will continue to work. | |
892 | ||
870d6656 TH |
893 | Say N if you are unsure. |
894 | ||
7c756e6e TH |
895 | config DEBUG_FORCE_WEAK_PER_CPU |
896 | bool "Force weak per-cpu definitions" | |
897 | depends on DEBUG_KERNEL | |
898 | help | |
899 | s390 and alpha require percpu variables in modules to be | |
900 | defined weak to work around addressing range issue which | |
901 | puts the following two restrictions on percpu variable | |
902 | definitions. | |
903 | ||
904 | 1. percpu symbols must be unique whether static or not | |
905 | 2. percpu variables can't be defined inside a function | |
906 | ||
907 | To ensure that generic code follows the above rules, this | |
908 | option forces all percpu variables to be defined as weak. | |
909 | ||
8bb31b9d AG |
910 | config LKDTM |
911 | tristate "Linux Kernel Dump Test Tool Module" | |
0347af4e | 912 | depends on DEBUG_FS |
fddd9cf8 | 913 | depends on BLOCK |
8bb31b9d AG |
914 | default n |
915 | help | |
916 | This module enables testing of the different dumping mechanisms by | |
917 | inducing system failures at predefined crash points. | |
918 | If you don't need it: say N | |
919 | Choose M here to compile this code as a module. The module will be | |
920 | called lkdtm. | |
921 | ||
922 | Documentation on how to use the module can be found in | |
0347af4e | 923 | Documentation/fault-injection/provoke-crashes.txt |
6ff1cb35 | 924 | |
c9d221f8 AM |
925 | config CPU_NOTIFIER_ERROR_INJECT |
926 | tristate "CPU notifier error injection module" | |
927 | depends on HOTPLUG_CPU && DEBUG_KERNEL | |
928 | help | |
929 | This option provides a kernel module that can be used to test | |
930 | the error handling of the cpu notifiers | |
931 | ||
932 | To compile this code as a module, choose M here: the module will | |
933 | be called cpu-notifier-error-inject. | |
934 | ||
935 | If unsure, say N. | |
936 | ||
6ff1cb35 | 937 | config FAULT_INJECTION |
1ab8509a AM |
938 | bool "Fault-injection framework" |
939 | depends on DEBUG_KERNEL | |
329409ae AM |
940 | help |
941 | Provide fault-injection framework. | |
942 | For more details, see Documentation/fault-injection/. | |
6ff1cb35 | 943 | |
8a8b6502 | 944 | config FAILSLAB |
1ab8509a AM |
945 | bool "Fault-injection capability for kmalloc" |
946 | depends on FAULT_INJECTION | |
773ff60e | 947 | depends on SLAB || SLUB |
8a8b6502 | 948 | help |
1ab8509a | 949 | Provide fault-injection capability for kmalloc. |
8a8b6502 | 950 | |
933e312e AM |
951 | config FAIL_PAGE_ALLOC |
952 | bool "Fault-injection capabilitiy for alloc_pages()" | |
1ab8509a | 953 | depends on FAULT_INJECTION |
933e312e | 954 | help |
1ab8509a | 955 | Provide fault-injection capability for alloc_pages(). |
933e312e | 956 | |
c17bb495 | 957 | config FAIL_MAKE_REQUEST |
86327d19 | 958 | bool "Fault-injection capability for disk IO" |
581d4e28 | 959 | depends on FAULT_INJECTION && BLOCK |
c17bb495 | 960 | help |
1ab8509a | 961 | Provide fault-injection capability for disk IO. |
c17bb495 | 962 | |
581d4e28 | 963 | config FAIL_IO_TIMEOUT |
f4d01439 | 964 | bool "Fault-injection capability for faking disk interrupts" |
581d4e28 JA |
965 | depends on FAULT_INJECTION && BLOCK |
966 | help | |
967 | Provide fault-injection capability on end IO handling. This | |
968 | will make the block layer "forget" an interrupt as configured, | |
969 | thus exercising the error handling. | |
970 | ||
971 | Only works with drivers that use the generic timeout handling, | |
972 | for others it wont do anything. | |
973 | ||
6ff1cb35 AM |
974 | config FAULT_INJECTION_DEBUG_FS |
975 | bool "Debugfs entries for fault-injection capabilities" | |
1ab8509a | 976 | depends on FAULT_INJECTION && SYSFS && DEBUG_FS |
6ff1cb35 | 977 | help |
1ab8509a | 978 | Enable configuration of fault-injection capabilities via debugfs. |
1df49008 AM |
979 | |
980 | config FAULT_INJECTION_STACKTRACE_FILTER | |
981 | bool "stacktrace filter for fault-injection capabilities" | |
982 | depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT | |
6d690dca | 983 | depends on !X86_64 |
1df49008 | 984 | select STACKTRACE |
79aac889 | 985 | select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE |
1df49008 AM |
986 | help |
987 | Provide stacktrace filter for fault-injection capabilities | |
267c4025 | 988 | |
9745512c AV |
989 | config LATENCYTOP |
990 | bool "Latency measuring infrastructure" | |
79aac889 | 991 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE |
9745512c AV |
992 | select KALLSYMS |
993 | select KALLSYMS_ALL | |
994 | select STACKTRACE | |
995 | select SCHEDSTATS | |
996 | select SCHED_DEBUG | |
aa7d9350 | 997 | depends on HAVE_LATENCYTOP_SUPPORT |
9745512c AV |
998 | help |
999 | Enable this option if you want to use the LatencyTOP tool | |
1000 | to find out which userspace is blocking on what kernel operations. | |
1001 | ||
9e94cd32 AK |
1002 | config SYSCTL_SYSCALL_CHECK |
1003 | bool "Sysctl checks" | |
83ac201b | 1004 | depends on SYSCTL |
9e94cd32 AK |
1005 | ---help--- |
1006 | sys_sysctl uses binary paths that have been found challenging | |
1007 | to properly maintain and use. This enables checks that help | |
1008 | you to keep things correct. | |
1009 | ||
6a11f75b | 1010 | source mm/Kconfig.debug |
16444a8a ACM |
1011 | source kernel/trace/Kconfig |
1012 | ||
f212ec4b | 1013 | config PROVIDE_OHCI1394_DMA_INIT |
080de8c2 | 1014 | bool "Remote debugging over FireWire early on boot" |
f212ec4b BK |
1015 | depends on PCI && X86 |
1016 | help | |
1017 | If you want to debug problems which hang or crash the kernel early | |
1018 | on boot and the crashing machine has a FireWire port, you can use | |
1019 | this feature to remotely access the memory of the crashed machine | |
1020 | over FireWire. This employs remote DMA as part of the OHCI1394 | |
1021 | specification which is now the standard for FireWire controllers. | |
1022 | ||
1023 | With remote DMA, you can monitor the printk buffer remotely using | |
1024 | firescope and access all memory below 4GB using fireproxy from gdb. | |
1025 | Even controlling a kernel debugger is possible using remote DMA. | |
1026 | ||
1027 | Usage: | |
1028 | ||
1029 | If ohci1394_dma=early is used as boot parameter, it will initialize | |
1030 | all OHCI1394 controllers which are found in the PCI config space. | |
1031 | ||
1032 | As all changes to the FireWire bus such as enabling and disabling | |
1033 | devices cause a bus reset and thereby disable remote DMA for all | |
1034 | devices, be sure to have the cable plugged and FireWire enabled on | |
1035 | the debugging host before booting the debug target for debugging. | |
1036 | ||
1037 | This code (~1k) is freed after boot. By then, the firewire stack | |
1038 | in charge of the OHCI-1394 controllers should be used instead. | |
1039 | ||
1040 | See Documentation/debugging-via-ohci1394.txt for more information. | |
9745512c | 1041 | |
080de8c2 SR |
1042 | config FIREWIRE_OHCI_REMOTE_DMA |
1043 | bool "Remote debugging over FireWire with firewire-ohci" | |
1044 | depends on FIREWIRE_OHCI | |
1045 | help | |
1046 | This option lets you use the FireWire bus for remote debugging | |
1047 | with help of the firewire-ohci driver. It enables unfiltered | |
1048 | remote DMA in firewire-ohci. | |
1049 | See Documentation/debugging-via-ohci1394.txt for more information. | |
1050 | ||
1051 | If unsure, say N. | |
1052 | ||
152de30b | 1053 | config BUILD_DOCSRC |
3794f3e8 RD |
1054 | bool "Build targets in Documentation/ tree" |
1055 | depends on HEADERS_CHECK | |
1056 | help | |
1057 | This option attempts to build objects from the source files in the | |
1058 | kernel Documentation/ tree. | |
1059 | ||
1060 | Say N if you are unsure. | |
1061 | ||
e9d376f0 | 1062 | config DYNAMIC_DEBUG |
86151fdf | 1063 | bool "Enable dynamic printk() support" |
346e15be JB |
1064 | default n |
1065 | depends on PRINTK | |
86151fdf | 1066 | depends on DEBUG_FS |
346e15be JB |
1067 | help |
1068 | ||
1069 | Compiles debug level messages into the kernel, which would not | |
1070 | otherwise be available at runtime. These messages can then be | |
86151fdf JB |
1071 | enabled/disabled based on various levels of scope - per source file, |
1072 | function, module, format string, and line number. This mechanism | |
1073 | implicitly enables all pr_debug() and dev_dbg() calls. The impact of | |
1074 | this compile option is a larger kernel text size of about 2%. | |
346e15be JB |
1075 | |
1076 | Usage: | |
1077 | ||
2b2f68b5 | 1078 | Dynamic debugging is controlled via the 'dynamic_debug/control' file, |
86151fdf JB |
1079 | which is contained in the 'debugfs' filesystem. Thus, the debugfs |
1080 | filesystem must first be mounted before making use of this feature. | |
2b2f68b5 | 1081 | We refer the control file as: <debugfs>/dynamic_debug/control. This |
86151fdf JB |
1082 | file contains a list of the debug statements that can be enabled. The |
1083 | format for each line of the file is: | |
346e15be | 1084 | |
86151fdf | 1085 | filename:lineno [module]function flags format |
346e15be | 1086 | |
86151fdf JB |
1087 | filename : source file of the debug statement |
1088 | lineno : line number of the debug statement | |
1089 | module : module that contains the debug statement | |
1090 | function : function that contains the debug statement | |
1091 | flags : 'p' means the line is turned 'on' for printing | |
1092 | format : the format used for the debug statement | |
346e15be JB |
1093 | |
1094 | From a live system: | |
1095 | ||
2b2f68b5 | 1096 | nullarbor:~ # cat <debugfs>/dynamic_debug/control |
86151fdf JB |
1097 | # filename:lineno [module]function flags format |
1098 | fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012" | |
1099 | fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012" | |
1100 | fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012" | |
346e15be | 1101 | |
86151fdf | 1102 | Example usage: |
346e15be | 1103 | |
86151fdf JB |
1104 | // enable the message at line 1603 of file svcsock.c |
1105 | nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' > | |
2b2f68b5 | 1106 | <debugfs>/dynamic_debug/control |
346e15be | 1107 | |
86151fdf JB |
1108 | // enable all the messages in file svcsock.c |
1109 | nullarbor:~ # echo -n 'file svcsock.c +p' > | |
2b2f68b5 | 1110 | <debugfs>/dynamic_debug/control |
346e15be | 1111 | |
86151fdf JB |
1112 | // enable all the messages in the NFS server module |
1113 | nullarbor:~ # echo -n 'module nfsd +p' > | |
2b2f68b5 | 1114 | <debugfs>/dynamic_debug/control |
346e15be | 1115 | |
86151fdf JB |
1116 | // enable all 12 messages in the function svc_process() |
1117 | nullarbor:~ # echo -n 'func svc_process +p' > | |
2b2f68b5 | 1118 | <debugfs>/dynamic_debug/control |
346e15be | 1119 | |
86151fdf JB |
1120 | // disable all 12 messages in the function svc_process() |
1121 | nullarbor:~ # echo -n 'func svc_process -p' > | |
2b2f68b5 | 1122 | <debugfs>/dynamic_debug/control |
346e15be | 1123 | |
86151fdf | 1124 | See Documentation/dynamic-debug-howto.txt for additional information. |
346e15be | 1125 | |
5ee00bd4 JR |
1126 | config DMA_API_DEBUG |
1127 | bool "Enable debugging of DMA-API usage" | |
1128 | depends on HAVE_DMA_API_DEBUG | |
1129 | help | |
1130 | Enable this option to debug the use of the DMA API by device drivers. | |
1131 | With this option you will be able to detect common bugs in device | |
1132 | drivers like double-freeing of DMA mappings or freeing mappings that | |
1133 | were never allocated. | |
1134 | This option causes a performance degredation. Use only if you want | |
1135 | to debug device drivers. If unsure, say N. | |
346e15be | 1136 | |
86a89380 LB |
1137 | config ATOMIC64_SELFTEST |
1138 | bool "Perform an atomic64_t self-test at boot" | |
1139 | help | |
1140 | Enable this option to test the atomic64_t functions at boot. | |
1141 | ||
1142 | If unsure, say N. | |
1143 | ||
267c4025 | 1144 | source "samples/Kconfig" |
dc7d5527 JW |
1145 | |
1146 | source "lib/Kconfig.kgdb" | |
0a4af3b0 PE |
1147 | |
1148 | source "lib/Kconfig.kmemcheck" |