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1da177e4 LT |
1 | |
2 | config PRINTK_TIME | |
3 | bool "Show timing information on printks" | |
d3b8b6e5 | 4 | depends on PRINTK |
1da177e4 LT |
5 | help |
6 | Selecting this option causes timing information to be | |
7 | included in printk output. This allows you to measure | |
8 | the interval between kernel operations, including bootup | |
9 | operations. This is useful for identifying long delays | |
10 | in kernel startup. | |
11 | ||
de488443 JG |
12 | config ENABLE_WARN_DEPRECATED |
13 | bool "Enable __deprecated logic" | |
14 | default y | |
15 | help | |
16 | Enable the __deprecated logic in the kernel build. | |
17 | Disable this to suppress the "warning: 'foo' is deprecated | |
18 | (declared at kernel/power/somefile.c:1234)" messages. | |
19 | ||
cebc04ba AM |
20 | config ENABLE_MUST_CHECK |
21 | bool "Enable __must_check logic" | |
22 | default y | |
23 | help | |
24 | Enable the __must_check logic in the kernel build. Disable this to | |
25 | suppress the "warning: ignoring return value of 'foo', declared with | |
26 | attribute warn_unused_result" messages. | |
1da177e4 | 27 | |
35bb5b1e AK |
28 | config FRAME_WARN |
29 | int "Warn for stack frames larger than (needs gcc 4.4)" | |
30 | range 0 8192 | |
31 | default 1024 if !64BIT | |
32 | default 2048 if 64BIT | |
33 | help | |
34 | Tell gcc to warn at build time for stack frames larger than this. | |
35 | Setting this too low will cause a lot of warnings. | |
36 | Setting it to 0 disables the warning. | |
37 | Requires gcc 4.4 | |
38 | ||
1da177e4 LT |
39 | config MAGIC_SYSRQ |
40 | bool "Magic SysRq key" | |
f346f4b3 | 41 | depends on !UML |
1da177e4 LT |
42 | help |
43 | If you say Y here, you will have some control over the system even | |
44 | if the system crashes for example during kernel debugging (e.g., you | |
45 | will be able to flush the buffer cache to disk, reboot the system | |
46 | immediately or dump some status information). This is accomplished | |
47 | by pressing various keys while holding SysRq (Alt+PrintScreen). It | |
48 | also works on a serial console (on PC hardware at least), if you | |
49 | send a BREAK and then within 5 seconds a command keypress. The | |
50 | keys are documented in <file:Documentation/sysrq.txt>. Don't say Y | |
51 | unless you really know what this hack does. | |
52 | ||
f71d20e9 AV |
53 | config UNUSED_SYMBOLS |
54 | bool "Enable unused/obsolete exported symbols" | |
55 | default y if X86 | |
56 | help | |
57 | Unused but exported symbols make the kernel needlessly bigger. For | |
58 | that reason most of these unused exports will soon be removed. This | |
59 | option is provided temporarily to provide a transition period in case | |
60 | some external kernel module needs one of these symbols anyway. If you | |
61 | encounter such a case in your module, consider if you are actually | |
62 | using the right API. (rationale: since nobody in the kernel is using | |
63 | this in a module, there is a pretty good chance it's actually the | |
64 | wrong interface to use). If you really need the symbol, please send a | |
65 | mail to the linux kernel mailing list mentioning the symbol and why | |
66 | you really need it, and what the merge plan to the mainline kernel for | |
67 | your module is. | |
68 | ||
bf4735a4 DM |
69 | config DEBUG_FS |
70 | bool "Debug Filesystem" | |
71 | depends on SYSFS | |
72 | help | |
73 | debugfs is a virtual file system that kernel developers use to put | |
74 | debugging files into. Enable this option to be able to read and | |
75 | write to these files. | |
76 | ||
ff543332 RD |
77 | For detailed documentation on the debugfs API, see |
78 | Documentation/DocBook/filesystems. | |
79 | ||
bf4735a4 DM |
80 | If unsure, say N. |
81 | ||
82 | config HEADERS_CHECK | |
83 | bool "Run 'make headers_check' when building vmlinux" | |
84 | depends on !UML | |
85 | help | |
86 | This option will extract the user-visible kernel headers whenever | |
87 | building the kernel, and will run basic sanity checks on them to | |
88 | ensure that exported files do not attempt to include files which | |
89 | were not exported, etc. | |
90 | ||
91 | If you're making modifications to header files which are | |
92 | relevant for userspace, say 'Y', and check the headers | |
93 | exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in | |
94 | your build tree), to make sure they're suitable. | |
95 | ||
91341d4b SR |
96 | config DEBUG_SECTION_MISMATCH |
97 | bool "Enable full Section mismatch analysis" | |
e5f95c8b | 98 | depends on UNDEFINED |
fa2144ba SR |
99 | # This option is on purpose disabled for now. |
100 | # It will be enabled when we are down to a resonable number | |
101 | # of section mismatch warnings (< 10 for an allyesconfig build) | |
91341d4b SR |
102 | help |
103 | The section mismatch analysis checks if there are illegal | |
104 | references from one section to another section. | |
105 | Linux will during link or during runtime drop some sections | |
106 | and any use of code/data previously in these sections will | |
107 | most likely result in an oops. | |
108 | In the code functions and variables are annotated with | |
109 | __init, __devinit etc. (see full list in include/linux/init.h) | |
d6fbfa4f GU |
110 | which results in the code/data being placed in specific sections. |
111 | The section mismatch analysis is always done after a full | |
112 | kernel build but enabling this option will in addition | |
91341d4b SR |
113 | do the following: |
114 | - Add the option -fno-inline-functions-called-once to gcc | |
115 | When inlining a function annotated __init in a non-init | |
d6fbfa4f | 116 | function we would lose the section information and thus |
91341d4b | 117 | the analysis would not catch the illegal reference. |
d6fbfa4f | 118 | This option tells gcc to inline less but will also |
91341d4b SR |
119 | result in a larger kernel. |
120 | - Run the section mismatch analysis for each module/built-in.o | |
121 | When we run the section mismatch analysis on vmlinux.o we | |
d6fbfa4f | 122 | lose valueble information about where the mismatch was |
91341d4b SR |
123 | introduced. |
124 | Running the analysis for each module/built-in.o file | |
125 | will tell where the mismatch happens much closer to the | |
126 | source. The drawback is that we will report the same | |
127 | mismatch at least twice. | |
588ccd73 SR |
128 | - Enable verbose reporting from modpost to help solving |
129 | the section mismatches reported. | |
91341d4b | 130 | |
f346f4b3 AB |
131 | config DEBUG_KERNEL |
132 | bool "Kernel debugging" | |
133 | help | |
134 | Say Y here if you are developing drivers or trying to debug and | |
135 | identify kernel problems. | |
136 | ||
a304e1b8 DW |
137 | config DEBUG_SHIRQ |
138 | bool "Debug shared IRQ handlers" | |
139 | depends on DEBUG_KERNEL && GENERIC_HARDIRQS | |
140 | help | |
141 | Enable this to generate a spurious interrupt as soon as a shared | |
142 | interrupt handler is registered, and just before one is deregistered. | |
143 | Drivers ought to be able to handle interrupts coming in at those | |
144 | points; some don't and need to be caught. | |
145 | ||
8446f1d3 IM |
146 | config DETECT_SOFTLOCKUP |
147 | bool "Detect Soft Lockups" | |
dea20a3f | 148 | depends on DEBUG_KERNEL && !S390 |
8446f1d3 IM |
149 | default y |
150 | help | |
151 | Say Y here to enable the kernel to detect "soft lockups", | |
152 | which are bugs that cause the kernel to loop in kernel | |
9c44bc03 | 153 | mode for more than 60 seconds, without giving other tasks a |
8446f1d3 IM |
154 | chance to run. |
155 | ||
156 | When a soft-lockup is detected, the kernel will print the | |
157 | current stack trace (which you should report), but the | |
158 | system will stay locked up. This feature has negligible | |
159 | overhead. | |
160 | ||
161 | (Note that "hard lockups" are separate type of bugs that | |
162 | can be detected via the NMI-watchdog, on platforms that | |
163 | support it.) | |
164 | ||
9c44bc03 IM |
165 | config BOOTPARAM_SOFTLOCKUP_PANIC |
166 | bool "Panic (Reboot) On Soft Lockups" | |
167 | depends on DETECT_SOFTLOCKUP | |
168 | help | |
169 | Say Y here to enable the kernel to panic on "soft lockups", | |
170 | which are bugs that cause the kernel to loop in kernel | |
171 | mode for more than 60 seconds, without giving other tasks a | |
172 | chance to run. | |
173 | ||
174 | The panic can be used in combination with panic_timeout, | |
175 | to cause the system to reboot automatically after a | |
176 | lockup has been detected. This feature is useful for | |
177 | high-availability systems that have uptime guarantees and | |
178 | where a lockup must be resolved ASAP. | |
179 | ||
180 | Say N if unsure. | |
181 | ||
182 | config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE | |
183 | int | |
184 | depends on DETECT_SOFTLOCKUP | |
185 | range 0 1 | |
186 | default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC | |
187 | default 1 if BOOTPARAM_SOFTLOCKUP_PANIC | |
188 | ||
b642b6d3 IM |
189 | config SCHED_DEBUG |
190 | bool "Collect scheduler debugging info" | |
191 | depends on DEBUG_KERNEL && PROC_FS | |
192 | default y | |
193 | help | |
194 | If you say Y here, the /proc/sched_debug file will be provided | |
195 | that can help debug the scheduler. The runtime overhead of this | |
196 | option is minimal. | |
197 | ||
1da177e4 LT |
198 | config SCHEDSTATS |
199 | bool "Collect scheduler statistics" | |
200 | depends on DEBUG_KERNEL && PROC_FS | |
201 | help | |
202 | If you say Y here, additional code will be inserted into the | |
203 | scheduler and related routines to collect statistics about | |
204 | scheduler behavior and provide them in /proc/schedstat. These | |
205 | stats may be useful for both tuning and debugging the scheduler | |
206 | If you aren't debugging the scheduler or trying to tune a specific | |
207 | application, you can say N to avoid the very slight overhead | |
208 | this adds. | |
209 | ||
82f67cd9 IM |
210 | config TIMER_STATS |
211 | bool "Collect kernel timers statistics" | |
212 | depends on DEBUG_KERNEL && PROC_FS | |
213 | help | |
214 | If you say Y here, additional code will be inserted into the | |
215 | timer routines to collect statistics about kernel timers being | |
216 | reprogrammed. The statistics can be read from /proc/timer_stats. | |
217 | The statistics collection is started by writing 1 to /proc/timer_stats, | |
218 | writing 0 stops it. This feature is useful to collect information | |
c1a834dc IM |
219 | about timer usage patterns in kernel and userspace. This feature |
220 | is lightweight if enabled in the kernel config but not activated | |
221 | (it defaults to deactivated on bootup and will only be activated | |
222 | if some application like powertop activates it explicitly). | |
82f67cd9 | 223 | |
3ac7fe5a TG |
224 | config DEBUG_OBJECTS |
225 | bool "Debug object operations" | |
226 | depends on DEBUG_KERNEL | |
227 | help | |
228 | If you say Y here, additional code will be inserted into the | |
229 | kernel to track the life time of various objects and validate | |
230 | the operations on those objects. | |
231 | ||
232 | config DEBUG_OBJECTS_SELFTEST | |
233 | bool "Debug objects selftest" | |
234 | depends on DEBUG_OBJECTS | |
235 | help | |
236 | This enables the selftest of the object debug code. | |
237 | ||
238 | config DEBUG_OBJECTS_FREE | |
239 | bool "Debug objects in freed memory" | |
240 | depends on DEBUG_OBJECTS | |
241 | help | |
242 | This enables checks whether a k/v free operation frees an area | |
243 | which contains an object which has not been deactivated | |
244 | properly. This can make kmalloc/kfree-intensive workloads | |
245 | much slower. | |
246 | ||
c6f3a97f TG |
247 | config DEBUG_OBJECTS_TIMERS |
248 | bool "Debug timer objects" | |
249 | depends on DEBUG_OBJECTS | |
250 | help | |
251 | If you say Y here, additional code will be inserted into the | |
252 | timer routines to track the life time of timer objects and | |
253 | validate the timer operations. | |
254 | ||
3ae70205 IM |
255 | config DEBUG_OBJECTS_ENABLE_DEFAULT |
256 | int "debug_objects bootup default value (0-1)" | |
257 | range 0 1 | |
258 | default "1" | |
259 | depends on DEBUG_OBJECTS | |
260 | help | |
261 | Debug objects boot parameter default value | |
262 | ||
1da177e4 | 263 | config DEBUG_SLAB |
4a2f0acf | 264 | bool "Debug slab memory allocations" |
50dd26ba | 265 | depends on DEBUG_KERNEL && SLAB |
1da177e4 LT |
266 | help |
267 | Say Y here to have the kernel do limited verification on memory | |
268 | allocation as well as poisoning memory on free to catch use of freed | |
269 | memory. This can make kmalloc/kfree-intensive workloads much slower. | |
270 | ||
871751e2 AV |
271 | config DEBUG_SLAB_LEAK |
272 | bool "Memory leak debugging" | |
273 | depends on DEBUG_SLAB | |
274 | ||
f0630fff CL |
275 | config SLUB_DEBUG_ON |
276 | bool "SLUB debugging on by default" | |
277 | depends on SLUB && SLUB_DEBUG | |
278 | default n | |
279 | help | |
280 | Boot with debugging on by default. SLUB boots by default with | |
281 | the runtime debug capabilities switched off. Enabling this is | |
282 | equivalent to specifying the "slub_debug" parameter on boot. | |
283 | There is no support for more fine grained debug control like | |
284 | possible with slub_debug=xxx. SLUB debugging may be switched | |
285 | off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying | |
286 | "slub_debug=-". | |
287 | ||
8ff12cfc CL |
288 | config SLUB_STATS |
289 | default n | |
290 | bool "Enable SLUB performance statistics" | |
5b06c853 | 291 | depends on SLUB && SLUB_DEBUG && SYSFS |
8ff12cfc CL |
292 | help |
293 | SLUB statistics are useful to debug SLUBs allocation behavior in | |
294 | order find ways to optimize the allocator. This should never be | |
295 | enabled for production use since keeping statistics slows down | |
296 | the allocator by a few percentage points. The slabinfo command | |
297 | supports the determination of the most active slabs to figure | |
298 | out which slabs are relevant to a particular load. | |
299 | Try running: slabinfo -DA | |
300 | ||
1da177e4 LT |
301 | config DEBUG_PREEMPT |
302 | bool "Debug preemptible kernel" | |
048c8bc9 | 303 | depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64) |
1da177e4 LT |
304 | default y |
305 | help | |
306 | If you say Y here then the kernel will use a debug variant of the | |
307 | commonly used smp_processor_id() function and will print warnings | |
308 | if kernel code uses it in a preemption-unsafe way. Also, the kernel | |
309 | will detect preemption count underflows. | |
310 | ||
e7eebaf6 IM |
311 | config DEBUG_RT_MUTEXES |
312 | bool "RT Mutex debugging, deadlock detection" | |
e7eebaf6 IM |
313 | depends on DEBUG_KERNEL && RT_MUTEXES |
314 | help | |
315 | This allows rt mutex semantics violations and rt mutex related | |
316 | deadlocks (lockups) to be detected and reported automatically. | |
317 | ||
318 | config DEBUG_PI_LIST | |
319 | bool | |
320 | default y | |
321 | depends on DEBUG_RT_MUTEXES | |
322 | ||
61a87122 TG |
323 | config RT_MUTEX_TESTER |
324 | bool "Built-in scriptable tester for rt-mutexes" | |
a1583d3e | 325 | depends on DEBUG_KERNEL && RT_MUTEXES |
61a87122 TG |
326 | help |
327 | This option enables a rt-mutex tester. | |
328 | ||
1da177e4 | 329 | config DEBUG_SPINLOCK |
4d9f34ad | 330 | bool "Spinlock and rw-lock debugging: basic checks" |
1da177e4 LT |
331 | depends on DEBUG_KERNEL |
332 | help | |
333 | Say Y here and build SMP to catch missing spinlock initialization | |
334 | and certain other kinds of spinlock errors commonly made. This is | |
335 | best used in conjunction with the NMI watchdog so that spinlock | |
336 | deadlocks are also debuggable. | |
337 | ||
4d9f34ad IM |
338 | config DEBUG_MUTEXES |
339 | bool "Mutex debugging: basic checks" | |
340 | depends on DEBUG_KERNEL | |
341 | help | |
342 | This feature allows mutex semantics violations to be detected and | |
343 | reported. | |
344 | ||
4d9f34ad IM |
345 | config DEBUG_LOCK_ALLOC |
346 | bool "Lock debugging: detect incorrect freeing of live locks" | |
517e7aa5 | 347 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
348 | select DEBUG_SPINLOCK |
349 | select DEBUG_MUTEXES | |
4d9f34ad IM |
350 | select LOCKDEP |
351 | help | |
352 | This feature will check whether any held lock (spinlock, rwlock, | |
353 | mutex or rwsem) is incorrectly freed by the kernel, via any of the | |
354 | memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), | |
355 | vfree(), etc.), whether a live lock is incorrectly reinitialized via | |
356 | spin_lock_init()/mutex_init()/etc., or whether there is any lock | |
357 | held during task exit. | |
358 | ||
359 | config PROVE_LOCKING | |
360 | bool "Lock debugging: prove locking correctness" | |
517e7aa5 | 361 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
362 | select LOCKDEP |
363 | select DEBUG_SPINLOCK | |
364 | select DEBUG_MUTEXES | |
4d9f34ad IM |
365 | select DEBUG_LOCK_ALLOC |
366 | default n | |
367 | help | |
368 | This feature enables the kernel to prove that all locking | |
369 | that occurs in the kernel runtime is mathematically | |
370 | correct: that under no circumstance could an arbitrary (and | |
371 | not yet triggered) combination of observed locking | |
372 | sequences (on an arbitrary number of CPUs, running an | |
373 | arbitrary number of tasks and interrupt contexts) cause a | |
374 | deadlock. | |
375 | ||
376 | In short, this feature enables the kernel to report locking | |
377 | related deadlocks before they actually occur. | |
378 | ||
379 | The proof does not depend on how hard and complex a | |
380 | deadlock scenario would be to trigger: how many | |
381 | participant CPUs, tasks and irq-contexts would be needed | |
382 | for it to trigger. The proof also does not depend on | |
383 | timing: if a race and a resulting deadlock is possible | |
384 | theoretically (no matter how unlikely the race scenario | |
385 | is), it will be proven so and will immediately be | |
386 | reported by the kernel (once the event is observed that | |
387 | makes the deadlock theoretically possible). | |
388 | ||
389 | If a deadlock is impossible (i.e. the locking rules, as | |
390 | observed by the kernel, are mathematically correct), the | |
391 | kernel reports nothing. | |
392 | ||
393 | NOTE: this feature can also be enabled for rwlocks, mutexes | |
394 | and rwsems - in which case all dependencies between these | |
395 | different locking variants are observed and mapped too, and | |
396 | the proof of observed correctness is also maintained for an | |
397 | arbitrary combination of these separate locking variants. | |
398 | ||
399 | For more details, see Documentation/lockdep-design.txt. | |
400 | ||
401 | config LOCKDEP | |
402 | bool | |
517e7aa5 | 403 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad | 404 | select STACKTRACE |
7563dc64 | 405 | select FRAME_POINTER if !X86 && !MIPS && !PPC |
4d9f34ad IM |
406 | select KALLSYMS |
407 | select KALLSYMS_ALL | |
408 | ||
f20786ff | 409 | config LOCK_STAT |
fdfb870f | 410 | bool "Lock usage statistics" |
f20786ff PZ |
411 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
412 | select LOCKDEP | |
413 | select DEBUG_SPINLOCK | |
414 | select DEBUG_MUTEXES | |
415 | select DEBUG_LOCK_ALLOC | |
416 | default n | |
417 | help | |
418 | This feature enables tracking lock contention points | |
419 | ||
a560aa48 PZ |
420 | For more details, see Documentation/lockstat.txt |
421 | ||
4d9f34ad IM |
422 | config DEBUG_LOCKDEP |
423 | bool "Lock dependency engine debugging" | |
517e7aa5 | 424 | depends on DEBUG_KERNEL && LOCKDEP |
4d9f34ad IM |
425 | help |
426 | If you say Y here, the lock dependency engine will do | |
427 | additional runtime checks to debug itself, at the price | |
428 | of more runtime overhead. | |
429 | ||
430 | config TRACE_IRQFLAGS | |
517e7aa5 | 431 | depends on DEBUG_KERNEL |
4d9f34ad IM |
432 | bool |
433 | default y | |
434 | depends on TRACE_IRQFLAGS_SUPPORT | |
435 | depends on PROVE_LOCKING | |
436 | ||
1da177e4 | 437 | config DEBUG_SPINLOCK_SLEEP |
4d9f34ad | 438 | bool "Spinlock debugging: sleep-inside-spinlock checking" |
1da177e4 LT |
439 | depends on DEBUG_KERNEL |
440 | help | |
441 | If you say Y here, various routines which may sleep will become very | |
442 | noisy if they are called with a spinlock held. | |
443 | ||
cae2ed9a IM |
444 | config DEBUG_LOCKING_API_SELFTESTS |
445 | bool "Locking API boot-time self-tests" | |
446 | depends on DEBUG_KERNEL | |
447 | help | |
448 | Say Y here if you want the kernel to run a short self-test during | |
449 | bootup. The self-test checks whether common types of locking bugs | |
450 | are detected by debugging mechanisms or not. (if you disable | |
451 | lock debugging then those bugs wont be detected of course.) | |
452 | The following locking APIs are covered: spinlocks, rwlocks, | |
453 | mutexes and rwsems. | |
454 | ||
8637c099 IM |
455 | config STACKTRACE |
456 | bool | |
457 | depends on STACKTRACE_SUPPORT | |
458 | ||
1da177e4 LT |
459 | config DEBUG_KOBJECT |
460 | bool "kobject debugging" | |
461 | depends on DEBUG_KERNEL | |
462 | help | |
463 | If you say Y here, some extra kobject debugging messages will be sent | |
464 | to the syslog. | |
465 | ||
466 | config DEBUG_HIGHMEM | |
467 | bool "Highmem debugging" | |
468 | depends on DEBUG_KERNEL && HIGHMEM | |
469 | help | |
470 | This options enables addition error checking for high memory systems. | |
471 | Disable for production systems. | |
472 | ||
473 | config DEBUG_BUGVERBOSE | |
474 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED | |
c8538a7a | 475 | depends on BUG |
b920de1b DH |
476 | depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \ |
477 | FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300 | |
1da177e4 LT |
478 | default !EMBEDDED |
479 | help | |
480 | Say Y here to make BUG() panics output the file name and line number | |
481 | of the BUG call as well as the EIP and oops trace. This aids | |
482 | debugging but costs about 70-100K of memory. | |
483 | ||
484 | config DEBUG_INFO | |
485 | bool "Compile the kernel with debug info" | |
486 | depends on DEBUG_KERNEL | |
487 | help | |
488 | If you say Y here the resulting kernel image will include | |
489 | debugging info resulting in a larger kernel image. | |
b72e53f8 AD |
490 | This adds debug symbols to the kernel and modules (gcc -g), and |
491 | is needed if you intend to use kernel crashdump or binary object | |
492 | tools like crash, kgdb, LKCD, gdb, etc on the kernel. | |
1da177e4 LT |
493 | Say Y here only if you plan to debug the kernel. |
494 | ||
495 | If unsure, say N. | |
496 | ||
a241ec65 PM |
497 | config DEBUG_VM |
498 | bool "Debug VM" | |
499 | depends on DEBUG_KERNEL | |
500 | help | |
13e7444b NP |
501 | Enable this to turn on extended checks in the virtual-memory system |
502 | that may impact performance. | |
a241ec65 PM |
503 | |
504 | If unsure, say N. | |
505 | ||
59ea7463 JS |
506 | config DEBUG_VIRTUAL |
507 | bool "Debug VM translations" | |
508 | depends on DEBUG_KERNEL && X86 | |
509 | help | |
510 | Enable some costly sanity checks in virtual to page code. This can | |
511 | catch mistakes with virt_to_page() and friends. | |
512 | ||
513 | If unsure, say N. | |
514 | ||
8feae131 DH |
515 | config DEBUG_NOMMU_REGIONS |
516 | bool "Debug the global anon/private NOMMU mapping region tree" | |
517 | depends on DEBUG_KERNEL && !MMU | |
518 | help | |
519 | This option causes the global tree of anonymous and private mapping | |
520 | regions to be regularly checked for invalid topology. | |
521 | ||
ad775f5a DH |
522 | config DEBUG_WRITECOUNT |
523 | bool "Debug filesystem writers count" | |
524 | depends on DEBUG_KERNEL | |
525 | help | |
526 | Enable this to catch wrong use of the writers count in struct | |
527 | vfsmount. This will increase the size of each file struct by | |
528 | 32 bits. | |
529 | ||
530 | If unsure, say N. | |
531 | ||
6b74ab97 MG |
532 | config DEBUG_MEMORY_INIT |
533 | bool "Debug memory initialisation" if EMBEDDED | |
534 | default !EMBEDDED | |
535 | help | |
536 | Enable this for additional checks during memory initialisation. | |
537 | The sanity checks verify aspects of the VM such as the memory model | |
538 | and other information provided by the architecture. Verbose | |
539 | information will be printed at KERN_DEBUG loglevel depending | |
540 | on the mminit_loglevel= command-line option. | |
541 | ||
542 | If unsure, say Y | |
543 | ||
199a9afc DJ |
544 | config DEBUG_LIST |
545 | bool "Debug linked list manipulation" | |
546 | depends on DEBUG_KERNEL | |
547 | help | |
548 | Enable this to turn on extended checks in the linked-list | |
549 | walking routines. | |
550 | ||
551 | If unsure, say N. | |
552 | ||
d6ec0842 JA |
553 | config DEBUG_SG |
554 | bool "Debug SG table operations" | |
555 | depends on DEBUG_KERNEL | |
556 | help | |
557 | Enable this to turn on checks on scatter-gather tables. This can | |
558 | help find problems with drivers that do not properly initialize | |
559 | their sg tables. | |
560 | ||
561 | If unsure, say N. | |
562 | ||
1b2439db AV |
563 | config DEBUG_NOTIFIERS |
564 | bool "Debug notifier call chains" | |
565 | depends on DEBUG_KERNEL | |
566 | help | |
567 | Enable this to turn on sanity checking for notifier call chains. | |
568 | This is most useful for kernel developers to make sure that | |
569 | modules properly unregister themselves from notifier chains. | |
570 | This is a relatively cheap check but if you care about maximum | |
571 | performance, say N. | |
572 | ||
1da177e4 LT |
573 | config FRAME_POINTER |
574 | bool "Compile the kernel with frame pointers" | |
b920de1b | 575 | depends on DEBUG_KERNEL && \ |
da4276b8 IM |
576 | (CRIS || M68K || M68KNOMMU || FRV || UML || S390 || \ |
577 | AVR32 || SUPERH || BLACKFIN || MN10300) || \ | |
578 | ARCH_WANT_FRAME_POINTERS | |
579 | default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS | |
580 | help | |
581 | If you say Y here the resulting kernel image will be slightly | |
582 | larger and slower, but it gives very useful debugging information | |
583 | in case of kernel bugs. (precise oopses/stacktraces/warnings) | |
1da177e4 | 584 | |
bfe8df3d RD |
585 | config BOOT_PRINTK_DELAY |
586 | bool "Delay each boot printk message by N milliseconds" | |
587 | depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY | |
588 | help | |
589 | This build option allows you to read kernel boot messages | |
590 | by inserting a short delay after each one. The delay is | |
591 | specified in milliseconds on the kernel command line, | |
592 | using "boot_delay=N". | |
593 | ||
594 | It is likely that you would also need to use "lpj=M" to preset | |
595 | the "loops per jiffie" value. | |
596 | See a previous boot log for the "lpj" value to use for your | |
597 | system, and then set "lpj=M" before setting "boot_delay=N". | |
598 | NOTE: Using this option may adversely affect SMP systems. | |
599 | I.e., processors other than the first one may not boot up. | |
600 | BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect | |
601 | what it believes to be lockup conditions. | |
602 | ||
a241ec65 PM |
603 | config RCU_TORTURE_TEST |
604 | tristate "torture tests for RCU" | |
605 | depends on DEBUG_KERNEL | |
606 | default n | |
607 | help | |
608 | This option provides a kernel module that runs torture tests | |
609 | on the RCU infrastructure. The kernel module may be built | |
610 | after the fact on the running kernel to be tested, if desired. | |
611 | ||
31a72bce PM |
612 | Say Y here if you want RCU torture tests to be built into |
613 | the kernel. | |
a241ec65 PM |
614 | Say M if you want the RCU torture tests to build as a module. |
615 | Say N if you are unsure. | |
8bb31b9d | 616 | |
31a72bce PM |
617 | config RCU_TORTURE_TEST_RUNNABLE |
618 | bool "torture tests for RCU runnable by default" | |
619 | depends on RCU_TORTURE_TEST = y | |
620 | default n | |
621 | help | |
622 | This option provides a way to build the RCU torture tests | |
623 | directly into the kernel without them starting up at boot | |
624 | time. You can use /proc/sys/kernel/rcutorture_runnable | |
625 | to manually override this setting. This /proc file is | |
626 | available only when the RCU torture tests have been built | |
627 | into the kernel. | |
628 | ||
629 | Say Y here if you want the RCU torture tests to start during | |
630 | boot (you probably don't). | |
631 | Say N here if you want the RCU torture tests to start only | |
632 | after being manually enabled via /proc. | |
633 | ||
2133b5d7 | 634 | config RCU_CPU_STALL_DETECTOR |
67182ae1 PM |
635 | bool "Check for stalled CPUs delaying RCU grace periods" |
636 | depends on CLASSIC_RCU | |
637 | default n | |
638 | help | |
639 | This option causes RCU to printk information on which | |
640 | CPUs are delaying the current grace period, but only when | |
641 | the grace period extends for excessive time periods. | |
64db4cff PM |
642 | |
643 | Say Y if you want RCU to perform such checks. | |
644 | ||
645 | Say N if you are unsure. | |
646 | ||
647 | config RCU_CPU_STALL_DETECTOR | |
648 | bool "Check for stalled CPUs delaying RCU grace periods" | |
649 | depends on CLASSIC_RCU || TREE_RCU | |
650 | default n | |
651 | help | |
652 | This option causes RCU to printk information on which | |
653 | CPUs are delaying the current grace period, but only when | |
654 | the grace period extends for excessive time periods. | |
67182ae1 PM |
655 | |
656 | Say Y if you want RCU to perform such checks. | |
657 | ||
658 | Say N if you are unsure. | |
659 | ||
8c1c9356 AM |
660 | config KPROBES_SANITY_TEST |
661 | bool "Kprobes sanity tests" | |
662 | depends on DEBUG_KERNEL | |
663 | depends on KPROBES | |
664 | default n | |
665 | help | |
666 | This option provides for testing basic kprobes functionality on | |
667 | boot. A sample kprobe, jprobe and kretprobe are inserted and | |
668 | verified for functionality. | |
669 | ||
670 | Say N if you are unsure. | |
671 | ||
6dab2778 AV |
672 | config BACKTRACE_SELF_TEST |
673 | tristate "Self test for the backtrace code" | |
674 | depends on DEBUG_KERNEL | |
675 | default n | |
676 | help | |
677 | This option provides a kernel module that can be used to test | |
678 | the kernel stack backtrace code. This option is not useful | |
679 | for distributions or general kernels, but only for kernel | |
680 | developers working on architecture code. | |
681 | ||
ad118c54 VN |
682 | Note that if you want to also test saved backtraces, you will |
683 | have to enable STACKTRACE as well. | |
684 | ||
6dab2778 AV |
685 | Say N if you are unsure. |
686 | ||
870d6656 TH |
687 | config DEBUG_BLOCK_EXT_DEVT |
688 | bool "Force extended block device numbers and spread them" | |
689 | depends on DEBUG_KERNEL | |
690 | depends on BLOCK | |
759f8ca3 | 691 | default n |
870d6656 | 692 | help |
0e11e342 TH |
693 | BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON |
694 | SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT | |
695 | YOU ARE DOING. Distros, please enable this and fix whatever | |
696 | is broken. | |
697 | ||
870d6656 TH |
698 | Conventionally, block device numbers are allocated from |
699 | predetermined contiguous area. However, extended block area | |
700 | may introduce non-contiguous block device numbers. This | |
701 | option forces most block device numbers to be allocated from | |
702 | the extended space and spreads them to discover kernel or | |
703 | userland code paths which assume predetermined contiguous | |
704 | device number allocation. | |
705 | ||
55dc7db7 TH |
706 | Note that turning on this debug option shuffles all the |
707 | device numbers for all IDE and SCSI devices including libata | |
708 | ones, so root partition specified using device number | |
709 | directly (via rdev or root=MAJ:MIN) won't work anymore. | |
710 | Textual device names (root=/dev/sdXn) will continue to work. | |
711 | ||
870d6656 TH |
712 | Say N if you are unsure. |
713 | ||
8bb31b9d AG |
714 | config LKDTM |
715 | tristate "Linux Kernel Dump Test Tool Module" | |
bf4735a4 | 716 | depends on DEBUG_KERNEL |
8bb31b9d | 717 | depends on KPROBES |
fddd9cf8 | 718 | depends on BLOCK |
8bb31b9d AG |
719 | default n |
720 | help | |
721 | This module enables testing of the different dumping mechanisms by | |
722 | inducing system failures at predefined crash points. | |
723 | If you don't need it: say N | |
724 | Choose M here to compile this code as a module. The module will be | |
725 | called lkdtm. | |
726 | ||
727 | Documentation on how to use the module can be found in | |
728 | drivers/misc/lkdtm.c | |
6ff1cb35 AM |
729 | |
730 | config FAULT_INJECTION | |
1ab8509a AM |
731 | bool "Fault-injection framework" |
732 | depends on DEBUG_KERNEL | |
329409ae AM |
733 | help |
734 | Provide fault-injection framework. | |
735 | For more details, see Documentation/fault-injection/. | |
6ff1cb35 | 736 | |
8a8b6502 | 737 | config FAILSLAB |
1ab8509a AM |
738 | bool "Fault-injection capability for kmalloc" |
739 | depends on FAULT_INJECTION | |
773ff60e | 740 | depends on SLAB || SLUB |
8a8b6502 | 741 | help |
1ab8509a | 742 | Provide fault-injection capability for kmalloc. |
8a8b6502 | 743 | |
933e312e AM |
744 | config FAIL_PAGE_ALLOC |
745 | bool "Fault-injection capabilitiy for alloc_pages()" | |
1ab8509a | 746 | depends on FAULT_INJECTION |
933e312e | 747 | help |
1ab8509a | 748 | Provide fault-injection capability for alloc_pages(). |
933e312e | 749 | |
c17bb495 | 750 | config FAIL_MAKE_REQUEST |
86327d19 | 751 | bool "Fault-injection capability for disk IO" |
581d4e28 | 752 | depends on FAULT_INJECTION && BLOCK |
c17bb495 | 753 | help |
1ab8509a | 754 | Provide fault-injection capability for disk IO. |
c17bb495 | 755 | |
581d4e28 JA |
756 | config FAIL_IO_TIMEOUT |
757 | bool "Faul-injection capability for faking disk interrupts" | |
758 | depends on FAULT_INJECTION && BLOCK | |
759 | help | |
760 | Provide fault-injection capability on end IO handling. This | |
761 | will make the block layer "forget" an interrupt as configured, | |
762 | thus exercising the error handling. | |
763 | ||
764 | Only works with drivers that use the generic timeout handling, | |
765 | for others it wont do anything. | |
766 | ||
6ff1cb35 AM |
767 | config FAULT_INJECTION_DEBUG_FS |
768 | bool "Debugfs entries for fault-injection capabilities" | |
1ab8509a | 769 | depends on FAULT_INJECTION && SYSFS && DEBUG_FS |
6ff1cb35 | 770 | help |
1ab8509a | 771 | Enable configuration of fault-injection capabilities via debugfs. |
1df49008 AM |
772 | |
773 | config FAULT_INJECTION_STACKTRACE_FILTER | |
774 | bool "stacktrace filter for fault-injection capabilities" | |
775 | depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT | |
6d690dca | 776 | depends on !X86_64 |
1df49008 | 777 | select STACKTRACE |
7563dc64 | 778 | select FRAME_POINTER if !PPC |
1df49008 AM |
779 | help |
780 | Provide stacktrace filter for fault-injection capabilities | |
267c4025 | 781 | |
9745512c AV |
782 | config LATENCYTOP |
783 | bool "Latency measuring infrastructure" | |
7563dc64 | 784 | select FRAME_POINTER if !MIPS && !PPC |
9745512c AV |
785 | select KALLSYMS |
786 | select KALLSYMS_ALL | |
787 | select STACKTRACE | |
788 | select SCHEDSTATS | |
789 | select SCHED_DEBUG | |
aa7d9350 | 790 | depends on HAVE_LATENCYTOP_SUPPORT |
9745512c AV |
791 | help |
792 | Enable this option if you want to use the LatencyTOP tool | |
793 | to find out which userspace is blocking on what kernel operations. | |
794 | ||
9e94cd32 AK |
795 | config SYSCTL_SYSCALL_CHECK |
796 | bool "Sysctl checks" | |
797 | depends on SYSCTL_SYSCALL | |
798 | ---help--- | |
799 | sys_sysctl uses binary paths that have been found challenging | |
800 | to properly maintain and use. This enables checks that help | |
801 | you to keep things correct. | |
802 | ||
16444a8a ACM |
803 | source kernel/trace/Kconfig |
804 | ||
f212ec4b | 805 | config PROVIDE_OHCI1394_DMA_INIT |
080de8c2 | 806 | bool "Remote debugging over FireWire early on boot" |
f212ec4b BK |
807 | depends on PCI && X86 |
808 | help | |
809 | If you want to debug problems which hang or crash the kernel early | |
810 | on boot and the crashing machine has a FireWire port, you can use | |
811 | this feature to remotely access the memory of the crashed machine | |
812 | over FireWire. This employs remote DMA as part of the OHCI1394 | |
813 | specification which is now the standard for FireWire controllers. | |
814 | ||
815 | With remote DMA, you can monitor the printk buffer remotely using | |
816 | firescope and access all memory below 4GB using fireproxy from gdb. | |
817 | Even controlling a kernel debugger is possible using remote DMA. | |
818 | ||
819 | Usage: | |
820 | ||
821 | If ohci1394_dma=early is used as boot parameter, it will initialize | |
822 | all OHCI1394 controllers which are found in the PCI config space. | |
823 | ||
824 | As all changes to the FireWire bus such as enabling and disabling | |
825 | devices cause a bus reset and thereby disable remote DMA for all | |
826 | devices, be sure to have the cable plugged and FireWire enabled on | |
827 | the debugging host before booting the debug target for debugging. | |
828 | ||
829 | This code (~1k) is freed after boot. By then, the firewire stack | |
830 | in charge of the OHCI-1394 controllers should be used instead. | |
831 | ||
832 | See Documentation/debugging-via-ohci1394.txt for more information. | |
9745512c | 833 | |
080de8c2 SR |
834 | config FIREWIRE_OHCI_REMOTE_DMA |
835 | bool "Remote debugging over FireWire with firewire-ohci" | |
836 | depends on FIREWIRE_OHCI | |
837 | help | |
838 | This option lets you use the FireWire bus for remote debugging | |
839 | with help of the firewire-ohci driver. It enables unfiltered | |
840 | remote DMA in firewire-ohci. | |
841 | See Documentation/debugging-via-ohci1394.txt for more information. | |
842 | ||
843 | If unsure, say N. | |
844 | ||
3794f3e8 RD |
845 | menuconfig BUILD_DOCSRC |
846 | bool "Build targets in Documentation/ tree" | |
847 | depends on HEADERS_CHECK | |
848 | help | |
849 | This option attempts to build objects from the source files in the | |
850 | kernel Documentation/ tree. | |
851 | ||
852 | Say N if you are unsure. | |
853 | ||
346e15be JB |
854 | config DYNAMIC_PRINTK_DEBUG |
855 | bool "Enable dynamic printk() call support" | |
856 | default n | |
857 | depends on PRINTK | |
858 | select PRINTK_DEBUG | |
859 | help | |
860 | ||
861 | Compiles debug level messages into the kernel, which would not | |
862 | otherwise be available at runtime. These messages can then be | |
863 | enabled/disabled on a per module basis. This mechanism implicitly | |
864 | enables all pr_debug() and dev_dbg() calls. The impact of this | |
865 | compile option is a larger kernel text size of about 2%. | |
866 | ||
867 | Usage: | |
868 | ||
869 | Dynamic debugging is controlled by the debugfs file, | |
870 | dynamic_printk/modules. This file contains a list of the modules that | |
871 | can be enabled. The format of the file is the module name, followed | |
872 | by a set of flags that can be enabled. The first flag is always the | |
873 | 'enabled' flag. For example: | |
874 | ||
875 | <module_name> <enabled=0/1> | |
876 | . | |
877 | . | |
878 | . | |
879 | ||
880 | <module_name> : Name of the module in which the debug call resides | |
881 | <enabled=0/1> : whether the messages are enabled or not | |
882 | ||
883 | From a live system: | |
884 | ||
885 | snd_hda_intel enabled=0 | |
886 | fixup enabled=0 | |
887 | driver enabled=0 | |
888 | ||
889 | Enable a module: | |
890 | ||
891 | $echo "set enabled=1 <module_name>" > dynamic_printk/modules | |
892 | ||
893 | Disable a module: | |
894 | ||
895 | $echo "set enabled=0 <module_name>" > dynamic_printk/modules | |
896 | ||
897 | Enable all modules: | |
898 | ||
899 | $echo "set enabled=1 all" > dynamic_printk/modules | |
900 | ||
901 | Disable all modules: | |
902 | ||
903 | $echo "set enabled=0 all" > dynamic_printk/modules | |
904 | ||
905 | Finally, passing "dynamic_printk" at the command line enables | |
906 | debugging for all modules. This mode can be turned off via the above | |
907 | disable command. | |
908 | ||
267c4025 | 909 | source "samples/Kconfig" |
dc7d5527 JW |
910 | |
911 | source "lib/Kconfig.kgdb" |