Root/
1 | menu "printk and dmesg options" |
2 | |
3 | config PRINTK_TIME |
4 | bool "Show timing information on printks" |
5 | depends on PRINTK |
6 | help |
7 | Selecting this option causes time stamps of the printk() |
8 | messages to be added to the output of the syslog() system |
9 | call and at the console. |
10 | |
11 | The timestamp is always recorded internally, and exported |
12 | to /dev/kmsg. This flag just specifies if the timestamp should |
13 | be included, not that the timestamp is recorded. |
14 | |
15 | The behavior is also controlled by the kernel command line |
16 | parameter printk.time=1. See Documentation/kernel-parameters.txt |
17 | |
18 | config DEFAULT_MESSAGE_LOGLEVEL |
19 | int "Default message log level (1-7)" |
20 | range 1 7 |
21 | default "4" |
22 | help |
23 | Default log level for printk statements with no specified priority. |
24 | |
25 | This was hard-coded to KERN_WARNING since at least 2.6.10 but folks |
26 | that are auditing their logs closely may want to set it to a lower |
27 | priority. |
28 | |
29 | config BOOT_PRINTK_DELAY |
30 | bool "Delay each boot printk message by N milliseconds" |
31 | depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY |
32 | help |
33 | This build option allows you to read kernel boot messages |
34 | by inserting a short delay after each one. The delay is |
35 | specified in milliseconds on the kernel command line, |
36 | using "boot_delay=N". |
37 | |
38 | It is likely that you would also need to use "lpj=M" to preset |
39 | the "loops per jiffie" value. |
40 | See a previous boot log for the "lpj" value to use for your |
41 | system, and then set "lpj=M" before setting "boot_delay=N". |
42 | NOTE: Using this option may adversely affect SMP systems. |
43 | I.e., processors other than the first one may not boot up. |
44 | BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect |
45 | what it believes to be lockup conditions. |
46 | |
47 | config DYNAMIC_DEBUG |
48 | bool "Enable dynamic printk() support" |
49 | default n |
50 | depends on PRINTK |
51 | depends on DEBUG_FS |
52 | help |
53 | |
54 | Compiles debug level messages into the kernel, which would not |
55 | otherwise be available at runtime. These messages can then be |
56 | enabled/disabled based on various levels of scope - per source file, |
57 | function, module, format string, and line number. This mechanism |
58 | implicitly compiles in all pr_debug() and dev_dbg() calls, which |
59 | enlarges the kernel text size by about 2%. |
60 | |
61 | If a source file is compiled with DEBUG flag set, any |
62 | pr_debug() calls in it are enabled by default, but can be |
63 | disabled at runtime as below. Note that DEBUG flag is |
64 | turned on by many CONFIG_*DEBUG* options. |
65 | |
66 | Usage: |
67 | |
68 | Dynamic debugging is controlled via the 'dynamic_debug/control' file, |
69 | which is contained in the 'debugfs' filesystem. Thus, the debugfs |
70 | filesystem must first be mounted before making use of this feature. |
71 | We refer the control file as: <debugfs>/dynamic_debug/control. This |
72 | file contains a list of the debug statements that can be enabled. The |
73 | format for each line of the file is: |
74 | |
75 | filename:lineno [module]function flags format |
76 | |
77 | filename : source file of the debug statement |
78 | lineno : line number of the debug statement |
79 | module : module that contains the debug statement |
80 | function : function that contains the debug statement |
81 | flags : '=p' means the line is turned 'on' for printing |
82 | format : the format used for the debug statement |
83 | |
84 | From a live system: |
85 | |
86 | nullarbor:~ # cat <debugfs>/dynamic_debug/control |
87 | # filename:lineno [module]function flags format |
88 | fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012" |
89 | fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012" |
90 | fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012" |
91 | |
92 | Example usage: |
93 | |
94 | // enable the message at line 1603 of file svcsock.c |
95 | nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' > |
96 | <debugfs>/dynamic_debug/control |
97 | |
98 | // enable all the messages in file svcsock.c |
99 | nullarbor:~ # echo -n 'file svcsock.c +p' > |
100 | <debugfs>/dynamic_debug/control |
101 | |
102 | // enable all the messages in the NFS server module |
103 | nullarbor:~ # echo -n 'module nfsd +p' > |
104 | <debugfs>/dynamic_debug/control |
105 | |
106 | // enable all 12 messages in the function svc_process() |
107 | nullarbor:~ # echo -n 'func svc_process +p' > |
108 | <debugfs>/dynamic_debug/control |
109 | |
110 | // disable all 12 messages in the function svc_process() |
111 | nullarbor:~ # echo -n 'func svc_process -p' > |
112 | <debugfs>/dynamic_debug/control |
113 | |
114 | See Documentation/dynamic-debug-howto.txt for additional information. |
115 | |
116 | endmenu # "printk and dmesg options" |
117 | |
118 | menu "Compile-time checks and compiler options" |
119 | |
120 | config DEBUG_INFO |
121 | bool "Compile the kernel with debug info" |
122 | depends on DEBUG_KERNEL |
123 | help |
124 | If you say Y here the resulting kernel image will include |
125 | debugging info resulting in a larger kernel image. |
126 | This adds debug symbols to the kernel and modules (gcc -g), and |
127 | is needed if you intend to use kernel crashdump or binary object |
128 | tools like crash, kgdb, LKCD, gdb, etc on the kernel. |
129 | Say Y here only if you plan to debug the kernel. |
130 | |
131 | If unsure, say N. |
132 | |
133 | config DEBUG_INFO_REDUCED |
134 | bool "Reduce debugging information" |
135 | depends on DEBUG_INFO |
136 | help |
137 | If you say Y here gcc is instructed to generate less debugging |
138 | information for structure types. This means that tools that |
139 | need full debugging information (like kgdb or systemtap) won't |
140 | be happy. But if you merely need debugging information to |
141 | resolve line numbers there is no loss. Advantage is that |
142 | build directory object sizes shrink dramatically over a full |
143 | DEBUG_INFO build and compile times are reduced too. |
144 | Only works with newer gcc versions. |
145 | |
146 | config ENABLE_WARN_DEPRECATED |
147 | bool "Enable __deprecated logic" |
148 | default y |
149 | help |
150 | Enable the __deprecated logic in the kernel build. |
151 | Disable this to suppress the "warning: 'foo' is deprecated |
152 | (declared at kernel/power/somefile.c:1234)" messages. |
153 | |
154 | config ENABLE_MUST_CHECK |
155 | bool "Enable __must_check logic" |
156 | default y |
157 | help |
158 | Enable the __must_check logic in the kernel build. Disable this to |
159 | suppress the "warning: ignoring return value of 'foo', declared with |
160 | attribute warn_unused_result" messages. |
161 | |
162 | config FRAME_WARN |
163 | int "Warn for stack frames larger than (needs gcc 4.4)" |
164 | range 0 8192 |
165 | default 1024 if !64BIT |
166 | default 2048 if 64BIT |
167 | help |
168 | Tell gcc to warn at build time for stack frames larger than this. |
169 | Setting this too low will cause a lot of warnings. |
170 | Setting it to 0 disables the warning. |
171 | Requires gcc 4.4 |
172 | |
173 | config STRIP_ASM_SYMS |
174 | bool "Strip assembler-generated symbols during link" |
175 | default n |
176 | help |
177 | Strip internal assembler-generated symbols during a link (symbols |
178 | that look like '.Lxxx') so they don't pollute the output of |
179 | get_wchan() and suchlike. |
180 | |
181 | config READABLE_ASM |
182 | bool "Generate readable assembler code" |
183 | depends on DEBUG_KERNEL |
184 | help |
185 | Disable some compiler optimizations that tend to generate human unreadable |
186 | assembler output. This may make the kernel slightly slower, but it helps |
187 | to keep kernel developers who have to stare a lot at assembler listings |
188 | sane. |
189 | |
190 | config UNUSED_SYMBOLS |
191 | bool "Enable unused/obsolete exported symbols" |
192 | default y if X86 |
193 | help |
194 | Unused but exported symbols make the kernel needlessly bigger. For |
195 | that reason most of these unused exports will soon be removed. This |
196 | option is provided temporarily to provide a transition period in case |
197 | some external kernel module needs one of these symbols anyway. If you |
198 | encounter such a case in your module, consider if you are actually |
199 | using the right API. (rationale: since nobody in the kernel is using |
200 | this in a module, there is a pretty good chance it's actually the |
201 | wrong interface to use). If you really need the symbol, please send a |
202 | mail to the linux kernel mailing list mentioning the symbol and why |
203 | you really need it, and what the merge plan to the mainline kernel for |
204 | your module is. |
205 | |
206 | config DEBUG_FS |
207 | bool "Debug Filesystem" |
208 | help |
209 | debugfs is a virtual file system that kernel developers use to put |
210 | debugging files into. Enable this option to be able to read and |
211 | write to these files. |
212 | |
213 | For detailed documentation on the debugfs API, see |
214 | Documentation/DocBook/filesystems. |
215 | |
216 | If unsure, say N. |
217 | |
218 | config HEADERS_CHECK |
219 | bool "Run 'make headers_check' when building vmlinux" |
220 | depends on !UML |
221 | help |
222 | This option will extract the user-visible kernel headers whenever |
223 | building the kernel, and will run basic sanity checks on them to |
224 | ensure that exported files do not attempt to include files which |
225 | were not exported, etc. |
226 | |
227 | If you're making modifications to header files which are |
228 | relevant for userspace, say 'Y', and check the headers |
229 | exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in |
230 | your build tree), to make sure they're suitable. |
231 | |
232 | config DEBUG_SECTION_MISMATCH |
233 | bool "Enable full Section mismatch analysis" |
234 | help |
235 | The section mismatch analysis checks if there are illegal |
236 | references from one section to another section. |
237 | During linktime or runtime, some sections are dropped; |
238 | any use of code/data previously in these sections would |
239 | most likely result in an oops. |
240 | In the code, functions and variables are annotated with |
241 | __init,, etc. (see the full list in include/linux/init.h), |
242 | which results in the code/data being placed in specific sections. |
243 | The section mismatch analysis is always performed after a full |
244 | kernel build, and enabling this option causes the following |
245 | additional steps to occur: |
246 | - Add the option -fno-inline-functions-called-once to gcc commands. |
247 | When inlining a function annotated with __init in a non-init |
248 | function, we would lose the section information and thus |
249 | the analysis would not catch the illegal reference. |
250 | This option tells gcc to inline less (but it does result in |
251 | a larger kernel). |
252 | - Run the section mismatch analysis for each module/built-in.o file. |
253 | When we run the section mismatch analysis on vmlinux.o, we |
254 | lose valueble information about where the mismatch was |
255 | introduced. |
256 | Running the analysis for each module/built-in.o file |
257 | tells where the mismatch happens much closer to the |
258 | source. The drawback is that the same mismatch is |
259 | reported at least twice. |
260 | - Enable verbose reporting from modpost in order to help resolve |
261 | the section mismatches that are reported. |
262 | |
263 | # |
264 | # Select this config option from the architecture Kconfig, if it |
265 | # is preferred to always offer frame pointers as a config |
266 | # option on the architecture (regardless of KERNEL_DEBUG): |
267 | # |
268 | config ARCH_WANT_FRAME_POINTERS |
269 | bool |
270 | help |
271 | |
272 | config FRAME_POINTER |
273 | bool "Compile the kernel with frame pointers" |
274 | depends on DEBUG_KERNEL && \ |
275 | (CRIS || M68K || FRV || UML || \ |
276 | AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \ |
277 | ARCH_WANT_FRAME_POINTERS |
278 | default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS |
279 | help |
280 | If you say Y here the resulting kernel image will be slightly |
281 | larger and slower, but it gives very useful debugging information |
282 | in case of kernel bugs. (precise oopses/stacktraces/warnings) |
283 | |
284 | config DEBUG_FORCE_WEAK_PER_CPU |
285 | bool "Force weak per-cpu definitions" |
286 | depends on DEBUG_KERNEL |
287 | help |
288 | s390 and alpha require percpu variables in modules to be |
289 | defined weak to work around addressing range issue which |
290 | puts the following two restrictions on percpu variable |
291 | definitions. |
292 | |
293 | 1. percpu symbols must be unique whether static or not |
294 | 2. percpu variables can't be defined inside a function |
295 | |
296 | To ensure that generic code follows the above rules, this |
297 | option forces all percpu variables to be defined as weak. |
298 | |
299 | endmenu # "Compiler options" |
300 | |
301 | config MAGIC_SYSRQ |
302 | bool "Magic SysRq key" |
303 | depends on !UML |
304 | help |
305 | If you say Y here, you will have some control over the system even |
306 | if the system crashes for example during kernel debugging (e.g., you |
307 | will be able to flush the buffer cache to disk, reboot the system |
308 | immediately or dump some status information). This is accomplished |
309 | by pressing various keys while holding SysRq (Alt+PrintScreen). It |
310 | also works on a serial console (on PC hardware at least), if you |
311 | send a BREAK and then within 5 seconds a command keypress. The |
312 | keys are documented in <file:Documentation/sysrq.txt>. Don't say Y |
313 | unless you really know what this hack does. |
314 | |
315 | config DEBUG_KERNEL |
316 | bool "Kernel debugging" |
317 | help |
318 | Say Y here if you are developing drivers or trying to debug and |
319 | identify kernel problems. |
320 | |
321 | menu "Memory Debugging" |
322 | |
323 | source mm/Kconfig.debug |
324 | |
325 | config DEBUG_OBJECTS |
326 | bool "Debug object operations" |
327 | depends on DEBUG_KERNEL |
328 | help |
329 | If you say Y here, additional code will be inserted into the |
330 | kernel to track the life time of various objects and validate |
331 | the operations on those objects. |
332 | |
333 | config DEBUG_OBJECTS_SELFTEST |
334 | bool "Debug objects selftest" |
335 | depends on DEBUG_OBJECTS |
336 | help |
337 | This enables the selftest of the object debug code. |
338 | |
339 | config DEBUG_OBJECTS_FREE |
340 | bool "Debug objects in freed memory" |
341 | depends on DEBUG_OBJECTS |
342 | help |
343 | This enables checks whether a k/v free operation frees an area |
344 | which contains an object which has not been deactivated |
345 | properly. This can make kmalloc/kfree-intensive workloads |
346 | much slower. |
347 | |
348 | config DEBUG_OBJECTS_TIMERS |
349 | bool "Debug timer objects" |
350 | depends on DEBUG_OBJECTS |
351 | help |
352 | If you say Y here, additional code will be inserted into the |
353 | timer routines to track the life time of timer objects and |
354 | validate the timer operations. |
355 | |
356 | config DEBUG_OBJECTS_WORK |
357 | bool "Debug work objects" |
358 | depends on DEBUG_OBJECTS |
359 | help |
360 | If you say Y here, additional code will be inserted into the |
361 | work queue routines to track the life time of work objects and |
362 | validate the work operations. |
363 | |
364 | config DEBUG_OBJECTS_RCU_HEAD |
365 | bool "Debug RCU callbacks objects" |
366 | depends on DEBUG_OBJECTS |
367 | help |
368 | Enable this to turn on debugging of RCU list heads (call_rcu() usage). |
369 | |
370 | config DEBUG_OBJECTS_PERCPU_COUNTER |
371 | bool "Debug percpu counter objects" |
372 | depends on DEBUG_OBJECTS |
373 | help |
374 | If you say Y here, additional code will be inserted into the |
375 | percpu counter routines to track the life time of percpu counter |
376 | objects and validate the percpu counter operations. |
377 | |
378 | config DEBUG_OBJECTS_ENABLE_DEFAULT |
379 | int "debug_objects bootup default value (0-1)" |
380 | range 0 1 |
381 | default "1" |
382 | depends on DEBUG_OBJECTS |
383 | help |
384 | Debug objects boot parameter default value |
385 | |
386 | config DEBUG_SLAB |
387 | bool "Debug slab memory allocations" |
388 | depends on DEBUG_KERNEL && SLAB && !KMEMCHECK |
389 | help |
390 | Say Y here to have the kernel do limited verification on memory |
391 | allocation as well as poisoning memory on free to catch use of freed |
392 | memory. This can make kmalloc/kfree-intensive workloads much slower. |
393 | |
394 | config DEBUG_SLAB_LEAK |
395 | bool "Memory leak debugging" |
396 | depends on DEBUG_SLAB |
397 | |
398 | config SLUB_DEBUG_ON |
399 | bool "SLUB debugging on by default" |
400 | depends on SLUB && SLUB_DEBUG && !KMEMCHECK |
401 | default n |
402 | help |
403 | Boot with debugging on by default. SLUB boots by default with |
404 | the runtime debug capabilities switched off. Enabling this is |
405 | equivalent to specifying the "slub_debug" parameter on boot. |
406 | There is no support for more fine grained debug control like |
407 | possible with slub_debug=xxx. SLUB debugging may be switched |
408 | off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying |
409 | "slub_debug=-". |
410 | |
411 | config SLUB_STATS |
412 | default n |
413 | bool "Enable SLUB performance statistics" |
414 | depends on SLUB && SYSFS |
415 | help |
416 | SLUB statistics are useful to debug SLUBs allocation behavior in |
417 | order find ways to optimize the allocator. This should never be |
418 | enabled for production use since keeping statistics slows down |
419 | the allocator by a few percentage points. The slabinfo command |
420 | supports the determination of the most active slabs to figure |
421 | out which slabs are relevant to a particular load. |
422 | Try running: slabinfo -DA |
423 | |
424 | config HAVE_DEBUG_KMEMLEAK |
425 | bool |
426 | |
427 | config DEBUG_KMEMLEAK |
428 | bool "Kernel memory leak detector" |
429 | depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK |
430 | select DEBUG_FS |
431 | select STACKTRACE if STACKTRACE_SUPPORT |
432 | select KALLSYMS |
433 | select CRC32 |
434 | help |
435 | Say Y here if you want to enable the memory leak |
436 | detector. The memory allocation/freeing is traced in a way |
437 | similar to the Boehm's conservative garbage collector, the |
438 | difference being that the orphan objects are not freed but |
439 | only shown in /sys/kernel/debug/kmemleak. Enabling this |
440 | feature will introduce an overhead to memory |
441 | allocations. See Documentation/kmemleak.txt for more |
442 | details. |
443 | |
444 | Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances |
445 | of finding leaks due to the slab objects poisoning. |
446 | |
447 | In order to access the kmemleak file, debugfs needs to be |
448 | mounted (usually at /sys/kernel/debug). |
449 | |
450 | config DEBUG_KMEMLEAK_EARLY_LOG_SIZE |
451 | int "Maximum kmemleak early log entries" |
452 | depends on DEBUG_KMEMLEAK |
453 | range 200 40000 |
454 | default 400 |
455 | help |
456 | Kmemleak must track all the memory allocations to avoid |
457 | reporting false positives. Since memory may be allocated or |
458 | freed before kmemleak is initialised, an early log buffer is |
459 | used to store these actions. If kmemleak reports "early log |
460 | buffer exceeded", please increase this value. |
461 | |
462 | config DEBUG_KMEMLEAK_TEST |
463 | tristate "Simple test for the kernel memory leak detector" |
464 | depends on DEBUG_KMEMLEAK && m |
465 | help |
466 | This option enables a module that explicitly leaks memory. |
467 | |
468 | If unsure, say N. |
469 | |
470 | config DEBUG_KMEMLEAK_DEFAULT_OFF |
471 | bool "Default kmemleak to off" |
472 | depends on DEBUG_KMEMLEAK |
473 | help |
474 | Say Y here to disable kmemleak by default. It can then be enabled |
475 | on the command line via kmemleak=on. |
476 | |
477 | config DEBUG_STACK_USAGE |
478 | bool "Stack utilization instrumentation" |
479 | depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG |
480 | help |
481 | Enables the display of the minimum amount of free stack which each |
482 | task has ever had available in the sysrq-T and sysrq-P debug output. |
483 | |
484 | This option will slow down process creation somewhat. |
485 | |
486 | config DEBUG_VM |
487 | bool "Debug VM" |
488 | depends on DEBUG_KERNEL |
489 | help |
490 | Enable this to turn on extended checks in the virtual-memory system |
491 | that may impact performance. |
492 | |
493 | If unsure, say N. |
494 | |
495 | config DEBUG_VM_RB |
496 | bool "Debug VM red-black trees" |
497 | depends on DEBUG_VM |
498 | help |
499 | Enable this to turn on more extended checks in the virtual-memory |
500 | system that may impact performance. |
501 | |
502 | If unsure, say N. |
503 | |
504 | config DEBUG_VIRTUAL |
505 | bool "Debug VM translations" |
506 | depends on DEBUG_KERNEL && X86 |
507 | help |
508 | Enable some costly sanity checks in virtual to page code. This can |
509 | catch mistakes with virt_to_page() and friends. |
510 | |
511 | If unsure, say N. |
512 | |
513 | config DEBUG_NOMMU_REGIONS |
514 | bool "Debug the global anon/private NOMMU mapping region tree" |
515 | depends on DEBUG_KERNEL && !MMU |
516 | help |
517 | This option causes the global tree of anonymous and private mapping |
518 | regions to be regularly checked for invalid topology. |
519 | |
520 | config DEBUG_MEMORY_INIT |
521 | bool "Debug memory initialisation" if EXPERT |
522 | default !EXPERT |
523 | help |
524 | Enable this for additional checks during memory initialisation. |
525 | The sanity checks verify aspects of the VM such as the memory model |
526 | and other information provided by the architecture. Verbose |
527 | information will be printed at KERN_DEBUG loglevel depending |
528 | on the mminit_loglevel= command-line option. |
529 | |
530 | If unsure, say Y |
531 | |
532 | config MEMORY_NOTIFIER_ERROR_INJECT |
533 | tristate "Memory hotplug notifier error injection module" |
534 | depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION |
535 | help |
536 | This option provides the ability to inject artificial errors to |
537 | memory hotplug notifier chain callbacks. It is controlled through |
538 | debugfs interface under /sys/kernel/debug/notifier-error-inject/memory |
539 | |
540 | If the notifier call chain should be failed with some events |
541 | notified, write the error code to "actions/<notifier event>/error". |
542 | |
543 | Example: Inject memory hotplug offline error (-12 == -ENOMEM) |
544 | |
545 | # cd /sys/kernel/debug/notifier-error-inject/memory |
546 | # echo -12 > actions/MEM_GOING_OFFLINE/error |
547 | # echo offline > /sys/devices/system/memory/memoryXXX/state |
548 | bash: echo: write error: Cannot allocate memory |
549 | |
550 | To compile this code as a module, choose M here: the module will |
551 | be called memory-notifier-error-inject. |
552 | |
553 | If unsure, say N. |
554 | |
555 | config DEBUG_PER_CPU_MAPS |
556 | bool "Debug access to per_cpu maps" |
557 | depends on DEBUG_KERNEL |
558 | depends on SMP |
559 | help |
560 | Say Y to verify that the per_cpu map being accessed has |
561 | been set up. This adds a fair amount of code to kernel memory |
562 | and decreases performance. |
563 | |
564 | Say N if unsure. |
565 | |
566 | config DEBUG_HIGHMEM |
567 | bool "Highmem debugging" |
568 | depends on DEBUG_KERNEL && HIGHMEM |
569 | help |
570 | This options enables addition error checking for high memory systems. |
571 | Disable for production systems. |
572 | |
573 | config HAVE_DEBUG_STACKOVERFLOW |
574 | bool |
575 | |
576 | config DEBUG_STACKOVERFLOW |
577 | bool "Check for stack overflows" |
578 | depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW |
579 | ---help--- |
580 | Say Y here if you want to check for overflows of kernel, IRQ |
581 | and exception stacks (if your archicture uses them). This |
582 | option will show detailed messages if free stack space drops |
583 | below a certain limit. |
584 | |
585 | These kinds of bugs usually occur when call-chains in the |
586 | kernel get too deep, especially when interrupts are |
587 | involved. |
588 | |
589 | Use this in cases where you see apparently random memory |
590 | corruption, especially if it appears in 'struct thread_info' |
591 | |
592 | If in doubt, say "N". |
593 | |
594 | source "lib/Kconfig.kmemcheck" |
595 | |
596 | endmenu # "Memory Debugging" |
597 | |
598 | config DEBUG_SHIRQ |
599 | bool "Debug shared IRQ handlers" |
600 | depends on DEBUG_KERNEL |
601 | help |
602 | Enable this to generate a spurious interrupt as soon as a shared |
603 | interrupt handler is registered, and just before one is deregistered. |
604 | Drivers ought to be able to handle interrupts coming in at those |
605 | points; some don't and need to be caught. |
606 | |
607 | menu "Debug Lockups and Hangs" |
608 | |
609 | config LOCKUP_DETECTOR |
610 | bool "Detect Hard and Soft Lockups" |
611 | depends on DEBUG_KERNEL && !S390 |
612 | help |
613 | Say Y here to enable the kernel to act as a watchdog to detect |
614 | hard and soft lockups. |
615 | |
616 | Softlockups are bugs that cause the kernel to loop in kernel |
617 | mode for more than 20 seconds, without giving other tasks a |
618 | chance to run. The current stack trace is displayed upon |
619 | detection and the system will stay locked up. |
620 | |
621 | Hardlockups are bugs that cause the CPU to loop in kernel mode |
622 | for more than 10 seconds, without letting other interrupts have a |
623 | chance to run. The current stack trace is displayed upon detection |
624 | and the system will stay locked up. |
625 | |
626 | The overhead should be minimal. A periodic hrtimer runs to |
627 | generate interrupts and kick the watchdog task every 4 seconds. |
628 | An NMI is generated every 10 seconds or so to check for hardlockups. |
629 | |
630 | The frequency of hrtimer and NMI events and the soft and hard lockup |
631 | thresholds can be controlled through the sysctl watchdog_thresh. |
632 | |
633 | config HARDLOCKUP_DETECTOR |
634 | def_bool y |
635 | depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG |
636 | depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI |
637 | |
638 | config BOOTPARAM_HARDLOCKUP_PANIC |
639 | bool "Panic (Reboot) On Hard Lockups" |
640 | depends on HARDLOCKUP_DETECTOR |
641 | help |
642 | Say Y here to enable the kernel to panic on "hard lockups", |
643 | which are bugs that cause the kernel to loop in kernel |
644 | mode with interrupts disabled for more than 10 seconds (configurable |
645 | using the watchdog_thresh sysctl). |
646 | |
647 | Say N if unsure. |
648 | |
649 | config BOOTPARAM_HARDLOCKUP_PANIC_VALUE |
650 | int |
651 | depends on HARDLOCKUP_DETECTOR |
652 | range 0 1 |
653 | default 0 if !BOOTPARAM_HARDLOCKUP_PANIC |
654 | default 1 if BOOTPARAM_HARDLOCKUP_PANIC |
655 | |
656 | config BOOTPARAM_SOFTLOCKUP_PANIC |
657 | bool "Panic (Reboot) On Soft Lockups" |
658 | depends on LOCKUP_DETECTOR |
659 | help |
660 | Say Y here to enable the kernel to panic on "soft lockups", |
661 | which are bugs that cause the kernel to loop in kernel |
662 | mode for more than 20 seconds (configurable using the watchdog_thresh |
663 | sysctl), without giving other tasks a chance to run. |
664 | |
665 | The panic can be used in combination with panic_timeout, |
666 | to cause the system to reboot automatically after a |
667 | lockup has been detected. This feature is useful for |
668 | high-availability systems that have uptime guarantees and |
669 | where a lockup must be resolved ASAP. |
670 | |
671 | Say N if unsure. |
672 | |
673 | config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE |
674 | int |
675 | depends on LOCKUP_DETECTOR |
676 | range 0 1 |
677 | default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC |
678 | default 1 if BOOTPARAM_SOFTLOCKUP_PANIC |
679 | |
680 | config DETECT_HUNG_TASK |
681 | bool "Detect Hung Tasks" |
682 | depends on DEBUG_KERNEL |
683 | default LOCKUP_DETECTOR |
684 | help |
685 | Say Y here to enable the kernel to detect "hung tasks", |
686 | which are bugs that cause the task to be stuck in |
687 | uninterruptible "D" state indefinitiley. |
688 | |
689 | When a hung task is detected, the kernel will print the |
690 | current stack trace (which you should report), but the |
691 | task will stay in uninterruptible state. If lockdep is |
692 | enabled then all held locks will also be reported. This |
693 | feature has negligible overhead. |
694 | |
695 | config DEFAULT_HUNG_TASK_TIMEOUT |
696 | int "Default timeout for hung task detection (in seconds)" |
697 | depends on DETECT_HUNG_TASK |
698 | default 120 |
699 | help |
700 | This option controls the default timeout (in seconds) used |
701 | to determine when a task has become non-responsive and should |
702 | be considered hung. |
703 | |
704 | It can be adjusted at runtime via the kernel.hung_task_timeout_secs |
705 | sysctl or by writing a value to |
706 | /proc/sys/kernel/hung_task_timeout_secs. |
707 | |
708 | A timeout of 0 disables the check. The default is two minutes. |
709 | Keeping the default should be fine in most cases. |
710 | |
711 | config BOOTPARAM_HUNG_TASK_PANIC |
712 | bool "Panic (Reboot) On Hung Tasks" |
713 | depends on DETECT_HUNG_TASK |
714 | help |
715 | Say Y here to enable the kernel to panic on "hung tasks", |
716 | which are bugs that cause the kernel to leave a task stuck |
717 | in uninterruptible "D" state. |
718 | |
719 | The panic can be used in combination with panic_timeout, |
720 | to cause the system to reboot automatically after a |
721 | hung task has been detected. This feature is useful for |
722 | high-availability systems that have uptime guarantees and |
723 | where a hung tasks must be resolved ASAP. |
724 | |
725 | Say N if unsure. |
726 | |
727 | config BOOTPARAM_HUNG_TASK_PANIC_VALUE |
728 | int |
729 | depends on DETECT_HUNG_TASK |
730 | range 0 1 |
731 | default 0 if !BOOTPARAM_HUNG_TASK_PANIC |
732 | default 1 if BOOTPARAM_HUNG_TASK_PANIC |
733 | |
734 | endmenu # "Debug lockups and hangs" |
735 | |
736 | config PANIC_ON_OOPS |
737 | bool "Panic on Oops" |
738 | help |
739 | Say Y here to enable the kernel to panic when it oopses. This |
740 | has the same effect as setting oops=panic on the kernel command |
741 | line. |
742 | |
743 | This feature is useful to ensure that the kernel does not do |
744 | anything erroneous after an oops which could result in data |
745 | corruption or other issues. |
746 | |
747 | Say N if unsure. |
748 | |
749 | config PANIC_ON_OOPS_VALUE |
750 | int |
751 | range 0 1 |
752 | default 0 if !PANIC_ON_OOPS |
753 | default 1 if PANIC_ON_OOPS |
754 | |
755 | config SCHED_DEBUG |
756 | bool "Collect scheduler debugging info" |
757 | depends on DEBUG_KERNEL && PROC_FS |
758 | default y |
759 | help |
760 | If you say Y here, the /proc/sched_debug file will be provided |
761 | that can help debug the scheduler. The runtime overhead of this |
762 | option is minimal. |
763 | |
764 | config SCHEDSTATS |
765 | bool "Collect scheduler statistics" |
766 | depends on DEBUG_KERNEL && PROC_FS |
767 | help |
768 | If you say Y here, additional code will be inserted into the |
769 | scheduler and related routines to collect statistics about |
770 | scheduler behavior and provide them in /proc/schedstat. These |
771 | stats may be useful for both tuning and debugging the scheduler |
772 | If you aren't debugging the scheduler or trying to tune a specific |
773 | application, you can say N to avoid the very slight overhead |
774 | this adds. |
775 | |
776 | config TIMER_STATS |
777 | bool "Collect kernel timers statistics" |
778 | depends on DEBUG_KERNEL && PROC_FS |
779 | help |
780 | If you say Y here, additional code will be inserted into the |
781 | timer routines to collect statistics about kernel timers being |
782 | reprogrammed. The statistics can be read from /proc/timer_stats. |
783 | The statistics collection is started by writing 1 to /proc/timer_stats, |
784 | writing 0 stops it. This feature is useful to collect information |
785 | about timer usage patterns in kernel and userspace. This feature |
786 | is lightweight if enabled in the kernel config but not activated |
787 | (it defaults to deactivated on bootup and will only be activated |
788 | if some application like powertop activates it explicitly). |
789 | |
790 | config DEBUG_PREEMPT |
791 | bool "Debug preemptible kernel" |
792 | depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT |
793 | default y |
794 | help |
795 | If you say Y here then the kernel will use a debug variant of the |
796 | commonly used smp_processor_id() function and will print warnings |
797 | if kernel code uses it in a preemption-unsafe way. Also, the kernel |
798 | will detect preemption count underflows. |
799 | |
800 | menu "Lock Debugging (spinlocks, mutexes, etc...)" |
801 | |
802 | config DEBUG_RT_MUTEXES |
803 | bool "RT Mutex debugging, deadlock detection" |
804 | depends on DEBUG_KERNEL && RT_MUTEXES |
805 | help |
806 | This allows rt mutex semantics violations and rt mutex related |
807 | deadlocks (lockups) to be detected and reported automatically. |
808 | |
809 | config DEBUG_PI_LIST |
810 | bool |
811 | default y |
812 | depends on DEBUG_RT_MUTEXES |
813 | |
814 | config RT_MUTEX_TESTER |
815 | bool "Built-in scriptable tester for rt-mutexes" |
816 | depends on DEBUG_KERNEL && RT_MUTEXES |
817 | help |
818 | This option enables a rt-mutex tester. |
819 | |
820 | config DEBUG_SPINLOCK |
821 | bool "Spinlock and rw-lock debugging: basic checks" |
822 | depends on DEBUG_KERNEL |
823 | select UNINLINE_SPIN_UNLOCK |
824 | help |
825 | Say Y here and build SMP to catch missing spinlock initialization |
826 | and certain other kinds of spinlock errors commonly made. This is |
827 | best used in conjunction with the NMI watchdog so that spinlock |
828 | deadlocks are also debuggable. |
829 | |
830 | config DEBUG_MUTEXES |
831 | bool "Mutex debugging: basic checks" |
832 | depends on DEBUG_KERNEL |
833 | help |
834 | This feature allows mutex semantics violations to be detected and |
835 | reported. |
836 | |
837 | config DEBUG_WW_MUTEX_SLOWPATH |
838 | bool "Wait/wound mutex debugging: Slowpath testing" |
839 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
840 | select DEBUG_LOCK_ALLOC |
841 | select DEBUG_SPINLOCK |
842 | select DEBUG_MUTEXES |
843 | help |
844 | This feature enables slowpath testing for w/w mutex users by |
845 | injecting additional -EDEADLK wound/backoff cases. Together with |
846 | the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this |
847 | will test all possible w/w mutex interface abuse with the |
848 | exception of simply not acquiring all the required locks. |
849 | |
850 | config DEBUG_LOCK_ALLOC |
851 | bool "Lock debugging: detect incorrect freeing of live locks" |
852 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
853 | select DEBUG_SPINLOCK |
854 | select DEBUG_MUTEXES |
855 | select LOCKDEP |
856 | help |
857 | This feature will check whether any held lock (spinlock, rwlock, |
858 | mutex or rwsem) is incorrectly freed by the kernel, via any of the |
859 | memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), |
860 | vfree(), etc.), whether a live lock is incorrectly reinitialized via |
861 | spin_lock_init()/mutex_init()/etc., or whether there is any lock |
862 | held during task exit. |
863 | |
864 | config PROVE_LOCKING |
865 | bool "Lock debugging: prove locking correctness" |
866 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
867 | select LOCKDEP |
868 | select DEBUG_SPINLOCK |
869 | select DEBUG_MUTEXES |
870 | select DEBUG_LOCK_ALLOC |
871 | select TRACE_IRQFLAGS |
872 | default n |
873 | help |
874 | This feature enables the kernel to prove that all locking |
875 | that occurs in the kernel runtime is mathematically |
876 | correct: that under no circumstance could an arbitrary (and |
877 | not yet triggered) combination of observed locking |
878 | sequences (on an arbitrary number of CPUs, running an |
879 | arbitrary number of tasks and interrupt contexts) cause a |
880 | deadlock. |
881 | |
882 | In short, this feature enables the kernel to report locking |
883 | related deadlocks before they actually occur. |
884 | |
885 | The proof does not depend on how hard and complex a |
886 | deadlock scenario would be to trigger: how many |
887 | participant CPUs, tasks and irq-contexts would be needed |
888 | for it to trigger. The proof also does not depend on |
889 | timing: if a race and a resulting deadlock is possible |
890 | theoretically (no matter how unlikely the race scenario |
891 | is), it will be proven so and will immediately be |
892 | reported by the kernel (once the event is observed that |
893 | makes the deadlock theoretically possible). |
894 | |
895 | If a deadlock is impossible (i.e. the locking rules, as |
896 | observed by the kernel, are mathematically correct), the |
897 | kernel reports nothing. |
898 | |
899 | NOTE: this feature can also be enabled for rwlocks, mutexes |
900 | and rwsems - in which case all dependencies between these |
901 | different locking variants are observed and mapped too, and |
902 | the proof of observed correctness is also maintained for an |
903 | arbitrary combination of these separate locking variants. |
904 | |
905 | For more details, see Documentation/lockdep-design.txt. |
906 | |
907 | config LOCKDEP |
908 | bool |
909 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
910 | select STACKTRACE |
911 | select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC |
912 | select KALLSYMS |
913 | select KALLSYMS_ALL |
914 | |
915 | config LOCK_STAT |
916 | bool "Lock usage statistics" |
917 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
918 | select LOCKDEP |
919 | select DEBUG_SPINLOCK |
920 | select DEBUG_MUTEXES |
921 | select DEBUG_LOCK_ALLOC |
922 | default n |
923 | help |
924 | This feature enables tracking lock contention points |
925 | |
926 | For more details, see Documentation/lockstat.txt |
927 | |
928 | This also enables lock events required by "perf lock", |
929 | subcommand of perf. |
930 | If you want to use "perf lock", you also need to turn on |
931 | CONFIG_EVENT_TRACING. |
932 | |
933 | CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. |
934 | (CONFIG_LOCKDEP defines "acquire" and "release" events.) |
935 | |
936 | config DEBUG_LOCKDEP |
937 | bool "Lock dependency engine debugging" |
938 | depends on DEBUG_KERNEL && LOCKDEP |
939 | help |
940 | If you say Y here, the lock dependency engine will do |
941 | additional runtime checks to debug itself, at the price |
942 | of more runtime overhead. |
943 | |
944 | config DEBUG_ATOMIC_SLEEP |
945 | bool "Sleep inside atomic section checking" |
946 | select PREEMPT_COUNT |
947 | depends on DEBUG_KERNEL |
948 | help |
949 | If you say Y here, various routines which may sleep will become very |
950 | noisy if they are called inside atomic sections: when a spinlock is |
951 | held, inside an rcu read side critical section, inside preempt disabled |
952 | sections, inside an interrupt, etc... |
953 | |
954 | config DEBUG_LOCKING_API_SELFTESTS |
955 | bool "Locking API boot-time self-tests" |
956 | depends on DEBUG_KERNEL |
957 | help |
958 | Say Y here if you want the kernel to run a short self-test during |
959 | bootup. The self-test checks whether common types of locking bugs |
960 | are detected by debugging mechanisms or not. (if you disable |
961 | lock debugging then those bugs wont be detected of course.) |
962 | The following locking APIs are covered: spinlocks, rwlocks, |
963 | mutexes and rwsems. |
964 | |
965 | endmenu # lock debugging |
966 | |
967 | config TRACE_IRQFLAGS |
968 | bool |
969 | help |
970 | Enables hooks to interrupt enabling and disabling for |
971 | either tracing or lock debugging. |
972 | |
973 | config STACKTRACE |
974 | bool |
975 | depends on STACKTRACE_SUPPORT |
976 | |
977 | config DEBUG_KOBJECT |
978 | bool "kobject debugging" |
979 | depends on DEBUG_KERNEL |
980 | help |
981 | If you say Y here, some extra kobject debugging messages will be sent |
982 | to the syslog. |
983 | |
984 | config DEBUG_KOBJECT_RELEASE |
985 | bool "kobject release debugging" |
986 | depends on DEBUG_OBJECTS_TIMERS |
987 | help |
988 | kobjects are reference counted objects. This means that their |
989 | last reference count put is not predictable, and the kobject can |
990 | live on past the point at which a driver decides to drop it's |
991 | initial reference to the kobject gained on allocation. An |
992 | example of this would be a struct device which has just been |
993 | unregistered. |
994 | |
995 | However, some buggy drivers assume that after such an operation, |
996 | the memory backing the kobject can be immediately freed. This |
997 | goes completely against the principles of a refcounted object. |
998 | |
999 | If you say Y here, the kernel will delay the release of kobjects |
1000 | on the last reference count to improve the visibility of this |
1001 | kind of kobject release bug. |
1002 | |
1003 | config HAVE_DEBUG_BUGVERBOSE |
1004 | bool |
1005 | |
1006 | config DEBUG_BUGVERBOSE |
1007 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT |
1008 | depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE) |
1009 | default y |
1010 | help |
1011 | Say Y here to make BUG() panics output the file name and line number |
1012 | of the BUG call as well as the EIP and oops trace. This aids |
1013 | debugging but costs about 70-100K of memory. |
1014 | |
1015 | config DEBUG_WRITECOUNT |
1016 | bool "Debug filesystem writers count" |
1017 | depends on DEBUG_KERNEL |
1018 | help |
1019 | Enable this to catch wrong use of the writers count in struct |
1020 | vfsmount. This will increase the size of each file struct by |
1021 | 32 bits. |
1022 | |
1023 | If unsure, say N. |
1024 | |
1025 | config DEBUG_LIST |
1026 | bool "Debug linked list manipulation" |
1027 | depends on DEBUG_KERNEL |
1028 | help |
1029 | Enable this to turn on extended checks in the linked-list |
1030 | walking routines. |
1031 | |
1032 | If unsure, say N. |
1033 | |
1034 | config DEBUG_SG |
1035 | bool "Debug SG table operations" |
1036 | depends on DEBUG_KERNEL |
1037 | help |
1038 | Enable this to turn on checks on scatter-gather tables. This can |
1039 | help find problems with drivers that do not properly initialize |
1040 | their sg tables. |
1041 | |
1042 | If unsure, say N. |
1043 | |
1044 | config DEBUG_NOTIFIERS |
1045 | bool "Debug notifier call chains" |
1046 | depends on DEBUG_KERNEL |
1047 | help |
1048 | Enable this to turn on sanity checking for notifier call chains. |
1049 | This is most useful for kernel developers to make sure that |
1050 | modules properly unregister themselves from notifier chains. |
1051 | This is a relatively cheap check but if you care about maximum |
1052 | performance, say N. |
1053 | |
1054 | config DEBUG_CREDENTIALS |
1055 | bool "Debug credential management" |
1056 | depends on DEBUG_KERNEL |
1057 | help |
1058 | Enable this to turn on some debug checking for credential |
1059 | management. The additional code keeps track of the number of |
1060 | pointers from task_structs to any given cred struct, and checks to |
1061 | see that this number never exceeds the usage count of the cred |
1062 | struct. |
1063 | |
1064 | Furthermore, if SELinux is enabled, this also checks that the |
1065 | security pointer in the cred struct is never seen to be invalid. |
1066 | |
1067 | If unsure, say N. |
1068 | |
1069 | menu "RCU Debugging" |
1070 | |
1071 | config PROVE_RCU |
1072 | bool "RCU debugging: prove RCU correctness" |
1073 | depends on PROVE_LOCKING |
1074 | default n |
1075 | help |
1076 | This feature enables lockdep extensions that check for correct |
1077 | use of RCU APIs. This is currently under development. Say Y |
1078 | if you want to debug RCU usage or help work on the PROVE_RCU |
1079 | feature. |
1080 | |
1081 | Say N if you are unsure. |
1082 | |
1083 | config PROVE_RCU_REPEATEDLY |
1084 | bool "RCU debugging: don't disable PROVE_RCU on first splat" |
1085 | depends on PROVE_RCU |
1086 | default n |
1087 | help |
1088 | By itself, PROVE_RCU will disable checking upon issuing the |
1089 | first warning (or "splat"). This feature prevents such |
1090 | disabling, allowing multiple RCU-lockdep warnings to be printed |
1091 | on a single reboot. |
1092 | |
1093 | Say Y to allow multiple RCU-lockdep warnings per boot. |
1094 | |
1095 | Say N if you are unsure. |
1096 | |
1097 | config PROVE_RCU_DELAY |
1098 | bool "RCU debugging: preemptible RCU race provocation" |
1099 | depends on DEBUG_KERNEL && PREEMPT_RCU |
1100 | default n |
1101 | help |
1102 | There is a class of races that involve an unlikely preemption |
1103 | of __rcu_read_unlock() just after ->rcu_read_lock_nesting has |
1104 | been set to INT_MIN. This feature inserts a delay at that |
1105 | point to increase the probability of these races. |
1106 | |
1107 | Say Y to increase probability of preemption of __rcu_read_unlock(). |
1108 | |
1109 | Say N if you are unsure. |
1110 | |
1111 | config SPARSE_RCU_POINTER |
1112 | bool "RCU debugging: sparse-based checks for pointer usage" |
1113 | default n |
1114 | help |
1115 | This feature enables the __rcu sparse annotation for |
1116 | RCU-protected pointers. This annotation will cause sparse |
1117 | to flag any non-RCU used of annotated pointers. This can be |
1118 | helpful when debugging RCU usage. Please note that this feature |
1119 | is not intended to enforce code cleanliness; it is instead merely |
1120 | a debugging aid. |
1121 | |
1122 | Say Y to make sparse flag questionable use of RCU-protected pointers |
1123 | |
1124 | Say N if you are unsure. |
1125 | |
1126 | config RCU_TORTURE_TEST |
1127 | tristate "torture tests for RCU" |
1128 | depends on DEBUG_KERNEL |
1129 | default n |
1130 | help |
1131 | This option provides a kernel module that runs torture tests |
1132 | on the RCU infrastructure. The kernel module may be built |
1133 | after the fact on the running kernel to be tested, if desired. |
1134 | |
1135 | Say Y here if you want RCU torture tests to be built into |
1136 | the kernel. |
1137 | Say M if you want the RCU torture tests to build as a module. |
1138 | Say N if you are unsure. |
1139 | |
1140 | config RCU_TORTURE_TEST_RUNNABLE |
1141 | bool "torture tests for RCU runnable by default" |
1142 | depends on RCU_TORTURE_TEST = y |
1143 | default n |
1144 | help |
1145 | This option provides a way to build the RCU torture tests |
1146 | directly into the kernel without them starting up at boot |
1147 | time. You can use /proc/sys/kernel/rcutorture_runnable |
1148 | to manually override this setting. This /proc file is |
1149 | available only when the RCU torture tests have been built |
1150 | into the kernel. |
1151 | |
1152 | Say Y here if you want the RCU torture tests to start during |
1153 | boot (you probably don't). |
1154 | Say N here if you want the RCU torture tests to start only |
1155 | after being manually enabled via /proc. |
1156 | |
1157 | config RCU_CPU_STALL_TIMEOUT |
1158 | int "RCU CPU stall timeout in seconds" |
1159 | depends on RCU_STALL_COMMON |
1160 | range 3 300 |
1161 | default 21 |
1162 | help |
1163 | If a given RCU grace period extends more than the specified |
1164 | number of seconds, a CPU stall warning is printed. If the |
1165 | RCU grace period persists, additional CPU stall warnings are |
1166 | printed at more widely spaced intervals. |
1167 | |
1168 | config RCU_CPU_STALL_VERBOSE |
1169 | bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR" |
1170 | depends on TREE_PREEMPT_RCU |
1171 | default y |
1172 | help |
1173 | This option causes RCU to printk detailed per-task information |
1174 | for any tasks that are stalling the current RCU grace period. |
1175 | |
1176 | Say N if you are unsure. |
1177 | |
1178 | Say Y if you want to enable such checks. |
1179 | |
1180 | config RCU_CPU_STALL_INFO |
1181 | bool "Print additional diagnostics on RCU CPU stall" |
1182 | depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL |
1183 | default n |
1184 | help |
1185 | For each stalled CPU that is aware of the current RCU grace |
1186 | period, print out additional per-CPU diagnostic information |
1187 | regarding scheduling-clock ticks, idle state, and, |
1188 | for RCU_FAST_NO_HZ kernels, idle-entry state. |
1189 | |
1190 | Say N if you are unsure. |
1191 | |
1192 | Say Y if you want to enable such diagnostics. |
1193 | |
1194 | config RCU_TRACE |
1195 | bool "Enable tracing for RCU" |
1196 | depends on DEBUG_KERNEL |
1197 | select TRACE_CLOCK |
1198 | help |
1199 | This option provides tracing in RCU which presents stats |
1200 | in debugfs for debugging RCU implementation. |
1201 | |
1202 | Say Y here if you want to enable RCU tracing |
1203 | Say N if you are unsure. |
1204 | |
1205 | endmenu # "RCU Debugging" |
1206 | |
1207 | config DEBUG_BLOCK_EXT_DEVT |
1208 | bool "Force extended block device numbers and spread them" |
1209 | depends on DEBUG_KERNEL |
1210 | depends on BLOCK |
1211 | default n |
1212 | help |
1213 | BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON |
1214 | SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT |
1215 | YOU ARE DOING. Distros, please enable this and fix whatever |
1216 | is broken. |
1217 | |
1218 | Conventionally, block device numbers are allocated from |
1219 | predetermined contiguous area. However, extended block area |
1220 | may introduce non-contiguous block device numbers. This |
1221 | option forces most block device numbers to be allocated from |
1222 | the extended space and spreads them to discover kernel or |
1223 | userland code paths which assume predetermined contiguous |
1224 | device number allocation. |
1225 | |
1226 | Note that turning on this debug option shuffles all the |
1227 | device numbers for all IDE and SCSI devices including libata |
1228 | ones, so root partition specified using device number |
1229 | directly (via rdev or root=MAJ:MIN) won't work anymore. |
1230 | Textual device names (root=/dev/sdXn) will continue to work. |
1231 | |
1232 | Say N if you are unsure. |
1233 | |
1234 | config NOTIFIER_ERROR_INJECTION |
1235 | tristate "Notifier error injection" |
1236 | depends on DEBUG_KERNEL |
1237 | select DEBUG_FS |
1238 | help |
1239 | This option provides the ability to inject artificial errors to |
1240 | specified notifier chain callbacks. It is useful to test the error |
1241 | handling of notifier call chain failures. |
1242 | |
1243 | Say N if unsure. |
1244 | |
1245 | config CPU_NOTIFIER_ERROR_INJECT |
1246 | tristate "CPU notifier error injection module" |
1247 | depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION |
1248 | help |
1249 | This option provides a kernel module that can be used to test |
1250 | the error handling of the cpu notifiers by injecting artificial |
1251 | errors to CPU notifier chain callbacks. It is controlled through |
1252 | debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu |
1253 | |
1254 | If the notifier call chain should be failed with some events |
1255 | notified, write the error code to "actions/<notifier event>/error". |
1256 | |
1257 | Example: Inject CPU offline error (-1 == -EPERM) |
1258 | |
1259 | # cd /sys/kernel/debug/notifier-error-inject/cpu |
1260 | # echo -1 > actions/CPU_DOWN_PREPARE/error |
1261 | # echo 0 > /sys/devices/system/cpu/cpu1/online |
1262 | bash: echo: write error: Operation not permitted |
1263 | |
1264 | To compile this code as a module, choose M here: the module will |
1265 | be called cpu-notifier-error-inject. |
1266 | |
1267 | If unsure, say N. |
1268 | |
1269 | config PM_NOTIFIER_ERROR_INJECT |
1270 | tristate "PM notifier error injection module" |
1271 | depends on PM && NOTIFIER_ERROR_INJECTION |
1272 | default m if PM_DEBUG |
1273 | help |
1274 | This option provides the ability to inject artificial errors to |
1275 | PM notifier chain callbacks. It is controlled through debugfs |
1276 | interface /sys/kernel/debug/notifier-error-inject/pm |
1277 | |
1278 | If the notifier call chain should be failed with some events |
1279 | notified, write the error code to "actions/<notifier event>/error". |
1280 | |
1281 | Example: Inject PM suspend error (-12 = -ENOMEM) |
1282 | |
1283 | # cd /sys/kernel/debug/notifier-error-inject/pm/ |
1284 | # echo -12 > actions/PM_SUSPEND_PREPARE/error |
1285 | # echo mem > /sys/power/state |
1286 | bash: echo: write error: Cannot allocate memory |
1287 | |
1288 | To compile this code as a module, choose M here: the module will |
1289 | be called pm-notifier-error-inject. |
1290 | |
1291 | If unsure, say N. |
1292 | |
1293 | config OF_RECONFIG_NOTIFIER_ERROR_INJECT |
1294 | tristate "OF reconfig notifier error injection module" |
1295 | depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION |
1296 | help |
1297 | This option provides the ability to inject artificial errors to |
1298 | OF reconfig notifier chain callbacks. It is controlled |
1299 | through debugfs interface under |
1300 | /sys/kernel/debug/notifier-error-inject/OF-reconfig/ |
1301 | |
1302 | If the notifier call chain should be failed with some events |
1303 | notified, write the error code to "actions/<notifier event>/error". |
1304 | |
1305 | To compile this code as a module, choose M here: the module will |
1306 | be called of-reconfig-notifier-error-inject. |
1307 | |
1308 | If unsure, say N. |
1309 | |
1310 | config FAULT_INJECTION |
1311 | bool "Fault-injection framework" |
1312 | depends on DEBUG_KERNEL |
1313 | help |
1314 | Provide fault-injection framework. |
1315 | For more details, see Documentation/fault-injection/. |
1316 | |
1317 | config FAILSLAB |
1318 | bool "Fault-injection capability for kmalloc" |
1319 | depends on FAULT_INJECTION |
1320 | depends on SLAB || SLUB |
1321 | help |
1322 | Provide fault-injection capability for kmalloc. |
1323 | |
1324 | config FAIL_PAGE_ALLOC |
1325 | bool "Fault-injection capabilitiy for alloc_pages()" |
1326 | depends on FAULT_INJECTION |
1327 | help |
1328 | Provide fault-injection capability for alloc_pages(). |
1329 | |
1330 | config FAIL_MAKE_REQUEST |
1331 | bool "Fault-injection capability for disk IO" |
1332 | depends on FAULT_INJECTION && BLOCK |
1333 | help |
1334 | Provide fault-injection capability for disk IO. |
1335 | |
1336 | config FAIL_IO_TIMEOUT |
1337 | bool "Fault-injection capability for faking disk interrupts" |
1338 | depends on FAULT_INJECTION && BLOCK |
1339 | help |
1340 | Provide fault-injection capability on end IO handling. This |
1341 | will make the block layer "forget" an interrupt as configured, |
1342 | thus exercising the error handling. |
1343 | |
1344 | Only works with drivers that use the generic timeout handling, |
1345 | for others it wont do anything. |
1346 | |
1347 | config FAIL_MMC_REQUEST |
1348 | bool "Fault-injection capability for MMC IO" |
1349 | select DEBUG_FS |
1350 | depends on FAULT_INJECTION && MMC |
1351 | help |
1352 | Provide fault-injection capability for MMC IO. |
1353 | This will make the mmc core return data errors. This is |
1354 | useful to test the error handling in the mmc block device |
1355 | and to test how the mmc host driver handles retries from |
1356 | the block device. |
1357 | |
1358 | config FAULT_INJECTION_DEBUG_FS |
1359 | bool "Debugfs entries for fault-injection capabilities" |
1360 | depends on FAULT_INJECTION && SYSFS && DEBUG_FS |
1361 | help |
1362 | Enable configuration of fault-injection capabilities via debugfs. |
1363 | |
1364 | config FAULT_INJECTION_STACKTRACE_FILTER |
1365 | bool "stacktrace filter for fault-injection capabilities" |
1366 | depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT |
1367 | depends on !X86_64 |
1368 | select STACKTRACE |
1369 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC |
1370 | help |
1371 | Provide stacktrace filter for fault-injection capabilities |
1372 | |
1373 | config LATENCYTOP |
1374 | bool "Latency measuring infrastructure" |
1375 | depends on HAVE_LATENCYTOP_SUPPORT |
1376 | depends on DEBUG_KERNEL |
1377 | depends on STACKTRACE_SUPPORT |
1378 | depends on PROC_FS |
1379 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC |
1380 | select KALLSYMS |
1381 | select KALLSYMS_ALL |
1382 | select STACKTRACE |
1383 | select SCHEDSTATS |
1384 | select SCHED_DEBUG |
1385 | help |
1386 | Enable this option if you want to use the LatencyTOP tool |
1387 | to find out which userspace is blocking on what kernel operations. |
1388 | |
1389 | config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS |
1390 | bool |
1391 | |
1392 | config DEBUG_STRICT_USER_COPY_CHECKS |
1393 | bool "Strict user copy size checks" |
1394 | depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS |
1395 | depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING |
1396 | help |
1397 | Enabling this option turns a certain set of sanity checks for user |
1398 | copy operations into compile time failures. |
1399 | |
1400 | The copy_from_user() etc checks are there to help test if there |
1401 | are sufficient security checks on the length argument of |
1402 | the copy operation, by having gcc prove that the argument is |
1403 | within bounds. |
1404 | |
1405 | If unsure, say N. |
1406 | |
1407 | source kernel/trace/Kconfig |
1408 | |
1409 | menu "Runtime Testing" |
1410 | |
1411 | config LKDTM |
1412 | tristate "Linux Kernel Dump Test Tool Module" |
1413 | depends on DEBUG_FS |
1414 | depends on BLOCK |
1415 | default n |
1416 | help |
1417 | This module enables testing of the different dumping mechanisms by |
1418 | inducing system failures at predefined crash points. |
1419 | If you don't need it: say N |
1420 | Choose M here to compile this code as a module. The module will be |
1421 | called lkdtm. |
1422 | |
1423 | Documentation on how to use the module can be found in |
1424 | Documentation/fault-injection/provoke-crashes.txt |
1425 | |
1426 | config TEST_LIST_SORT |
1427 | bool "Linked list sorting test" |
1428 | depends on DEBUG_KERNEL |
1429 | help |
1430 | Enable this to turn on 'list_sort()' function test. This test is |
1431 | executed only once during system boot, so affects only boot time. |
1432 | |
1433 | If unsure, say N. |
1434 | |
1435 | config KPROBES_SANITY_TEST |
1436 | bool "Kprobes sanity tests" |
1437 | depends on DEBUG_KERNEL |
1438 | depends on KPROBES |
1439 | default n |
1440 | help |
1441 | This option provides for testing basic kprobes functionality on |
1442 | boot. A sample kprobe, jprobe and kretprobe are inserted and |
1443 | verified for functionality. |
1444 | |
1445 | Say N if you are unsure. |
1446 | |
1447 | config BACKTRACE_SELF_TEST |
1448 | tristate "Self test for the backtrace code" |
1449 | depends on DEBUG_KERNEL |
1450 | default n |
1451 | help |
1452 | This option provides a kernel module that can be used to test |
1453 | the kernel stack backtrace code. This option is not useful |
1454 | for distributions or general kernels, but only for kernel |
1455 | developers working on architecture code. |
1456 | |
1457 | Note that if you want to also test saved backtraces, you will |
1458 | have to enable STACKTRACE as well. |
1459 | |
1460 | Say N if you are unsure. |
1461 | |
1462 | config RBTREE_TEST |
1463 | tristate "Red-Black tree test" |
1464 | depends on DEBUG_KERNEL |
1465 | help |
1466 | A benchmark measuring the performance of the rbtree library. |
1467 | Also includes rbtree invariant checks. |
1468 | |
1469 | config INTERVAL_TREE_TEST |
1470 | tristate "Interval tree test" |
1471 | depends on m && DEBUG_KERNEL |
1472 | help |
1473 | A benchmark measuring the performance of the interval tree library |
1474 | |
1475 | config ATOMIC64_SELFTEST |
1476 | bool "Perform an atomic64_t self-test at boot" |
1477 | help |
1478 | Enable this option to test the atomic64_t functions at boot. |
1479 | |
1480 | If unsure, say N. |
1481 | |
1482 | config ASYNC_RAID6_TEST |
1483 | tristate "Self test for hardware accelerated raid6 recovery" |
1484 | depends on ASYNC_RAID6_RECOV |
1485 | select ASYNC_MEMCPY |
1486 | ---help--- |
1487 | This is a one-shot self test that permutes through the |
1488 | recovery of all the possible two disk failure scenarios for a |
1489 | N-disk array. Recovery is performed with the asynchronous |
1490 | raid6 recovery routines, and will optionally use an offload |
1491 | engine if one is available. |
1492 | |
1493 | If unsure, say N. |
1494 | |
1495 | config TEST_STRING_HELPERS |
1496 | tristate "Test functions located in the string_helpers module at runtime" |
1497 | |
1498 | config TEST_KSTRTOX |
1499 | tristate "Test kstrto*() family of functions at runtime" |
1500 | |
1501 | endmenu # runtime tests |
1502 | |
1503 | config PROVIDE_OHCI1394_DMA_INIT |
1504 | bool "Remote debugging over FireWire early on boot" |
1505 | depends on PCI && X86 |
1506 | help |
1507 | If you want to debug problems which hang or crash the kernel early |
1508 | on boot and the crashing machine has a FireWire port, you can use |
1509 | this feature to remotely access the memory of the crashed machine |
1510 | over FireWire. This employs remote DMA as part of the OHCI1394 |
1511 | specification which is now the standard for FireWire controllers. |
1512 | |
1513 | With remote DMA, you can monitor the printk buffer remotely using |
1514 | firescope and access all memory below 4GB using fireproxy from gdb. |
1515 | Even controlling a kernel debugger is possible using remote DMA. |
1516 | |
1517 | Usage: |
1518 | |
1519 | If ohci1394_dma=early is used as boot parameter, it will initialize |
1520 | all OHCI1394 controllers which are found in the PCI config space. |
1521 | |
1522 | As all changes to the FireWire bus such as enabling and disabling |
1523 | devices cause a bus reset and thereby disable remote DMA for all |
1524 | devices, be sure to have the cable plugged and FireWire enabled on |
1525 | the debugging host before booting the debug target for debugging. |
1526 | |
1527 | This code (~1k) is freed after boot. By then, the firewire stack |
1528 | in charge of the OHCI-1394 controllers should be used instead. |
1529 | |
1530 | See Documentation/debugging-via-ohci1394.txt for more information. |
1531 | |
1532 | config FIREWIRE_OHCI_REMOTE_DMA |
1533 | bool "Remote debugging over FireWire with firewire-ohci" |
1534 | depends on FIREWIRE_OHCI |
1535 | help |
1536 | This option lets you use the FireWire bus for remote debugging |
1537 | with help of the firewire-ohci driver. It enables unfiltered |
1538 | remote DMA in firewire-ohci. |
1539 | See Documentation/debugging-via-ohci1394.txt for more information. |
1540 | |
1541 | If unsure, say N. |
1542 | |
1543 | config BUILD_DOCSRC |
1544 | bool "Build targets in Documentation/ tree" |
1545 | depends on HEADERS_CHECK |
1546 | help |
1547 | This option attempts to build objects from the source files in the |
1548 | kernel Documentation/ tree. |
1549 | |
1550 | Say N if you are unsure. |
1551 | |
1552 | config DMA_API_DEBUG |
1553 | bool "Enable debugging of DMA-API usage" |
1554 | depends on HAVE_DMA_API_DEBUG |
1555 | help |
1556 | Enable this option to debug the use of the DMA API by device drivers. |
1557 | With this option you will be able to detect common bugs in device |
1558 | drivers like double-freeing of DMA mappings or freeing mappings that |
1559 | were never allocated. |
1560 | This option causes a performance degredation. Use only if you want |
1561 | to debug device drivers. If unsure, say N. |
1562 | |
1563 | source "samples/Kconfig" |
1564 | |
1565 | source "lib/Kconfig.kgdb" |
1566 | |
1567 |
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