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Commit | Line | Data |
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604ff0dc | 1 | menu "printk and dmesg options" |
1da177e4 LT |
2 | |
3 | config PRINTK_TIME | |
4 | bool "Show timing information on printks" | |
d3b8b6e5 | 5 | depends on PRINTK |
1da177e4 | 6 | help |
649e6ee3 KS |
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 | |
1da177e4 | 17 | |
5af5bcb8 MSB |
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 | ||
604ff0dc DH |
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 | ||
6dfc0665 DH |
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 | ||
de488443 JG |
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 | ||
cebc04ba AM |
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. | |
1da177e4 | 161 | |
35bb5b1e AK |
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 | ||
99657c78 RD |
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 | ||
1873e870 AK |
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 | ||
f71d20e9 AV |
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 | ||
bf4735a4 DM |
206 | config DEBUG_FS |
207 | bool "Debug Filesystem" | |
bf4735a4 DM |
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 | ||
ff543332 RD |
213 | For detailed documentation on the debugfs API, see |
214 | Documentation/DocBook/filesystems. | |
215 | ||
bf4735a4 DM |
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 | ||
91341d4b SR |
232 | config DEBUG_SECTION_MISMATCH |
233 | bool "Enable full Section mismatch analysis" | |
91341d4b SR |
234 | help |
235 | The section mismatch analysis checks if there are illegal | |
236 | references from one section to another section. | |
e809ab01 MW |
237 | During linktime or runtime, some sections are dropped; |
238 | any use of code/data previously in these sections would | |
91341d4b | 239 | most likely result in an oops. |
e809ab01 | 240 | In the code, functions and variables are annotated with |
0db0628d | 241 | __init,, etc. (see the full list in include/linux/init.h), |
d6fbfa4f | 242 | which results in the code/data being placed in specific sections. |
e809ab01 MW |
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 | |
91341d4b | 249 | the analysis would not catch the illegal reference. |
e809ab01 MW |
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 | |
d6fbfa4f | 254 | lose valueble information about where the mismatch was |
91341d4b SR |
255 | introduced. |
256 | Running the analysis for each module/built-in.o file | |
e809ab01 MW |
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. | |
91341d4b | 262 | |
6dfc0665 DH |
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 | |
f346f4b3 | 270 | help |
f346f4b3 | 271 | |
6dfc0665 DH |
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 | |
a304e1b8 | 279 | help |
6dfc0665 DH |
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) | |
a304e1b8 | 283 | |
6dfc0665 DH |
284 | config DEBUG_FORCE_WEAK_PER_CPU |
285 | bool "Force weak per-cpu definitions" | |
286 | depends on DEBUG_KERNEL | |
8446f1d3 | 287 | help |
6dfc0665 DH |
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. | |
8446f1d3 | 292 | |
6dfc0665 DH |
293 | 1. percpu symbols must be unique whether static or not |
294 | 2. percpu variables can't be defined inside a function | |
8446f1d3 | 295 | |
6dfc0665 DH |
296 | To ensure that generic code follows the above rules, this |
297 | option forces all percpu variables to be defined as weak. | |
5f329089 | 298 | |
6dfc0665 | 299 | endmenu # "Compiler options" |
8446f1d3 | 300 | |
6dfc0665 DH |
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. | |
8446f1d3 | 314 | |
8eaede49 BH |
315 | config MAGIC_SYSRQ_DEFAULT_ENABLE |
316 | hex "Enable magic SysRq key functions by default" | |
317 | depends on MAGIC_SYSRQ | |
318 | default 0x1 | |
319 | help | |
320 | Specifies which SysRq key functions are enabled by default. | |
321 | This may be set to 1 or 0 to enable or disable them all, or | |
322 | to a bitmask as described in Documentation/sysrq.txt. | |
323 | ||
f346f4b3 AB |
324 | config DEBUG_KERNEL |
325 | bool "Kernel debugging" | |
fef2c9bc | 326 | help |
f346f4b3 AB |
327 | Say Y here if you are developing drivers or trying to debug and |
328 | identify kernel problems. | |
fef2c9bc | 329 | |
0610c8a8 | 330 | menu "Memory Debugging" |
fef2c9bc | 331 | |
0610c8a8 | 332 | source mm/Kconfig.debug |
fef2c9bc | 333 | |
0610c8a8 DH |
334 | config DEBUG_OBJECTS |
335 | bool "Debug object operations" | |
336 | depends on DEBUG_KERNEL | |
9c44bc03 | 337 | help |
0610c8a8 DH |
338 | If you say Y here, additional code will be inserted into the |
339 | kernel to track the life time of various objects and validate | |
340 | the operations on those objects. | |
9c44bc03 | 341 | |
0610c8a8 DH |
342 | config DEBUG_OBJECTS_SELFTEST |
343 | bool "Debug objects selftest" | |
344 | depends on DEBUG_OBJECTS | |
345 | help | |
346 | This enables the selftest of the object debug code. | |
9c44bc03 | 347 | |
0610c8a8 DH |
348 | config DEBUG_OBJECTS_FREE |
349 | bool "Debug objects in freed memory" | |
350 | depends on DEBUG_OBJECTS | |
351 | help | |
352 | This enables checks whether a k/v free operation frees an area | |
353 | which contains an object which has not been deactivated | |
354 | properly. This can make kmalloc/kfree-intensive workloads | |
355 | much slower. | |
3ac7fe5a | 356 | |
c6f3a97f TG |
357 | config DEBUG_OBJECTS_TIMERS |
358 | bool "Debug timer objects" | |
359 | depends on DEBUG_OBJECTS | |
360 | help | |
361 | If you say Y here, additional code will be inserted into the | |
362 | timer routines to track the life time of timer objects and | |
363 | validate the timer operations. | |
364 | ||
dc186ad7 TG |
365 | config DEBUG_OBJECTS_WORK |
366 | bool "Debug work objects" | |
367 | depends on DEBUG_OBJECTS | |
368 | help | |
369 | If you say Y here, additional code will be inserted into the | |
370 | work queue routines to track the life time of work objects and | |
371 | validate the work operations. | |
372 | ||
551d55a9 MD |
373 | config DEBUG_OBJECTS_RCU_HEAD |
374 | bool "Debug RCU callbacks objects" | |
fc2ecf7e | 375 | depends on DEBUG_OBJECTS |
551d55a9 MD |
376 | help |
377 | Enable this to turn on debugging of RCU list heads (call_rcu() usage). | |
378 | ||
e2852ae8 TH |
379 | config DEBUG_OBJECTS_PERCPU_COUNTER |
380 | bool "Debug percpu counter objects" | |
381 | depends on DEBUG_OBJECTS | |
382 | help | |
383 | If you say Y here, additional code will be inserted into the | |
384 | percpu counter routines to track the life time of percpu counter | |
385 | objects and validate the percpu counter operations. | |
386 | ||
3ae70205 IM |
387 | config DEBUG_OBJECTS_ENABLE_DEFAULT |
388 | int "debug_objects bootup default value (0-1)" | |
389 | range 0 1 | |
390 | default "1" | |
391 | depends on DEBUG_OBJECTS | |
392 | help | |
393 | Debug objects boot parameter default value | |
394 | ||
1da177e4 | 395 | config DEBUG_SLAB |
4a2f0acf | 396 | bool "Debug slab memory allocations" |
7d46d9e6 | 397 | depends on DEBUG_KERNEL && SLAB && !KMEMCHECK |
1da177e4 LT |
398 | help |
399 | Say Y here to have the kernel do limited verification on memory | |
400 | allocation as well as poisoning memory on free to catch use of freed | |
401 | memory. This can make kmalloc/kfree-intensive workloads much slower. | |
402 | ||
871751e2 AV |
403 | config DEBUG_SLAB_LEAK |
404 | bool "Memory leak debugging" | |
405 | depends on DEBUG_SLAB | |
406 | ||
f0630fff CL |
407 | config SLUB_DEBUG_ON |
408 | bool "SLUB debugging on by default" | |
7d46d9e6 | 409 | depends on SLUB && SLUB_DEBUG && !KMEMCHECK |
f0630fff CL |
410 | default n |
411 | help | |
412 | Boot with debugging on by default. SLUB boots by default with | |
413 | the runtime debug capabilities switched off. Enabling this is | |
414 | equivalent to specifying the "slub_debug" parameter on boot. | |
415 | There is no support for more fine grained debug control like | |
416 | possible with slub_debug=xxx. SLUB debugging may be switched | |
417 | off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying | |
418 | "slub_debug=-". | |
419 | ||
8ff12cfc CL |
420 | config SLUB_STATS |
421 | default n | |
422 | bool "Enable SLUB performance statistics" | |
ab4d5ed5 | 423 | depends on SLUB && SYSFS |
8ff12cfc CL |
424 | help |
425 | SLUB statistics are useful to debug SLUBs allocation behavior in | |
426 | order find ways to optimize the allocator. This should never be | |
427 | enabled for production use since keeping statistics slows down | |
428 | the allocator by a few percentage points. The slabinfo command | |
429 | supports the determination of the most active slabs to figure | |
430 | out which slabs are relevant to a particular load. | |
431 | Try running: slabinfo -DA | |
432 | ||
b69ec42b CM |
433 | config HAVE_DEBUG_KMEMLEAK |
434 | bool | |
435 | ||
3bba00d7 CM |
436 | config DEBUG_KMEMLEAK |
437 | bool "Kernel memory leak detector" | |
525c1f92 | 438 | depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK |
79e0d9bd | 439 | select DEBUG_FS |
3bba00d7 CM |
440 | select STACKTRACE if STACKTRACE_SUPPORT |
441 | select KALLSYMS | |
b60e26a2 | 442 | select CRC32 |
3bba00d7 CM |
443 | help |
444 | Say Y here if you want to enable the memory leak | |
445 | detector. The memory allocation/freeing is traced in a way | |
446 | similar to the Boehm's conservative garbage collector, the | |
447 | difference being that the orphan objects are not freed but | |
448 | only shown in /sys/kernel/debug/kmemleak. Enabling this | |
449 | feature will introduce an overhead to memory | |
450 | allocations. See Documentation/kmemleak.txt for more | |
451 | details. | |
452 | ||
0610c8a8 DH |
453 | Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances |
454 | of finding leaks due to the slab objects poisoning. | |
455 | ||
456 | In order to access the kmemleak file, debugfs needs to be | |
457 | mounted (usually at /sys/kernel/debug). | |
458 | ||
459 | config DEBUG_KMEMLEAK_EARLY_LOG_SIZE | |
460 | int "Maximum kmemleak early log entries" | |
461 | depends on DEBUG_KMEMLEAK | |
462 | range 200 40000 | |
463 | default 400 | |
464 | help | |
465 | Kmemleak must track all the memory allocations to avoid | |
466 | reporting false positives. Since memory may be allocated or | |
467 | freed before kmemleak is initialised, an early log buffer is | |
468 | used to store these actions. If kmemleak reports "early log | |
469 | buffer exceeded", please increase this value. | |
470 | ||
471 | config DEBUG_KMEMLEAK_TEST | |
472 | tristate "Simple test for the kernel memory leak detector" | |
473 | depends on DEBUG_KMEMLEAK && m | |
474 | help | |
475 | This option enables a module that explicitly leaks memory. | |
476 | ||
477 | If unsure, say N. | |
478 | ||
479 | config DEBUG_KMEMLEAK_DEFAULT_OFF | |
480 | bool "Default kmemleak to off" | |
481 | depends on DEBUG_KMEMLEAK | |
482 | help | |
483 | Say Y here to disable kmemleak by default. It can then be enabled | |
484 | on the command line via kmemleak=on. | |
485 | ||
486 | config DEBUG_STACK_USAGE | |
487 | bool "Stack utilization instrumentation" | |
488 | depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG | |
489 | help | |
490 | Enables the display of the minimum amount of free stack which each | |
491 | task has ever had available in the sysrq-T and sysrq-P debug output. | |
492 | ||
493 | This option will slow down process creation somewhat. | |
494 | ||
495 | config DEBUG_VM | |
496 | bool "Debug VM" | |
497 | depends on DEBUG_KERNEL | |
498 | help | |
499 | Enable this to turn on extended checks in the virtual-memory system | |
500 | that may impact performance. | |
501 | ||
502 | If unsure, say N. | |
503 | ||
504 | config DEBUG_VM_RB | |
505 | bool "Debug VM red-black trees" | |
506 | depends on DEBUG_VM | |
507 | help | |
508 | Enable this to turn on more extended checks in the virtual-memory | |
509 | system that may impact performance. | |
510 | ||
511 | If unsure, say N. | |
512 | ||
513 | config DEBUG_VIRTUAL | |
514 | bool "Debug VM translations" | |
515 | depends on DEBUG_KERNEL && X86 | |
516 | help | |
517 | Enable some costly sanity checks in virtual to page code. This can | |
518 | catch mistakes with virt_to_page() and friends. | |
519 | ||
520 | If unsure, say N. | |
521 | ||
522 | config DEBUG_NOMMU_REGIONS | |
523 | bool "Debug the global anon/private NOMMU mapping region tree" | |
524 | depends on DEBUG_KERNEL && !MMU | |
525 | help | |
526 | This option causes the global tree of anonymous and private mapping | |
527 | regions to be regularly checked for invalid topology. | |
528 | ||
529 | config DEBUG_MEMORY_INIT | |
530 | bool "Debug memory initialisation" if EXPERT | |
531 | default !EXPERT | |
532 | help | |
533 | Enable this for additional checks during memory initialisation. | |
534 | The sanity checks verify aspects of the VM such as the memory model | |
535 | and other information provided by the architecture. Verbose | |
536 | information will be printed at KERN_DEBUG loglevel depending | |
537 | on the mminit_loglevel= command-line option. | |
538 | ||
539 | If unsure, say Y | |
540 | ||
541 | config MEMORY_NOTIFIER_ERROR_INJECT | |
542 | tristate "Memory hotplug notifier error injection module" | |
543 | depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION | |
544 | help | |
545 | This option provides the ability to inject artificial errors to | |
546 | memory hotplug notifier chain callbacks. It is controlled through | |
547 | debugfs interface under /sys/kernel/debug/notifier-error-inject/memory | |
548 | ||
549 | If the notifier call chain should be failed with some events | |
550 | notified, write the error code to "actions/<notifier event>/error". | |
551 | ||
552 | Example: Inject memory hotplug offline error (-12 == -ENOMEM) | |
553 | ||
554 | # cd /sys/kernel/debug/notifier-error-inject/memory | |
555 | # echo -12 > actions/MEM_GOING_OFFLINE/error | |
556 | # echo offline > /sys/devices/system/memory/memoryXXX/state | |
557 | bash: echo: write error: Cannot allocate memory | |
558 | ||
559 | To compile this code as a module, choose M here: the module will | |
560 | be called memory-notifier-error-inject. | |
561 | ||
562 | If unsure, say N. | |
563 | ||
564 | config DEBUG_PER_CPU_MAPS | |
565 | bool "Debug access to per_cpu maps" | |
566 | depends on DEBUG_KERNEL | |
567 | depends on SMP | |
568 | help | |
569 | Say Y to verify that the per_cpu map being accessed has | |
570 | been set up. This adds a fair amount of code to kernel memory | |
571 | and decreases performance. | |
572 | ||
573 | Say N if unsure. | |
574 | ||
575 | config DEBUG_HIGHMEM | |
576 | bool "Highmem debugging" | |
577 | depends on DEBUG_KERNEL && HIGHMEM | |
578 | help | |
579 | This options enables addition error checking for high memory systems. | |
580 | Disable for production systems. | |
581 | ||
582 | config HAVE_DEBUG_STACKOVERFLOW | |
583 | bool | |
584 | ||
585 | config DEBUG_STACKOVERFLOW | |
586 | bool "Check for stack overflows" | |
587 | depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW | |
588 | ---help--- | |
589 | Say Y here if you want to check for overflows of kernel, IRQ | |
590 | and exception stacks (if your archicture uses them). This | |
591 | option will show detailed messages if free stack space drops | |
592 | below a certain limit. | |
593 | ||
594 | These kinds of bugs usually occur when call-chains in the | |
595 | kernel get too deep, especially when interrupts are | |
596 | involved. | |
597 | ||
598 | Use this in cases where you see apparently random memory | |
599 | corruption, especially if it appears in 'struct thread_info' | |
600 | ||
601 | If in doubt, say "N". | |
602 | ||
603 | source "lib/Kconfig.kmemcheck" | |
604 | ||
605 | endmenu # "Memory Debugging" | |
606 | ||
a304e1b8 DW |
607 | config DEBUG_SHIRQ |
608 | bool "Debug shared IRQ handlers" | |
0244ad00 | 609 | depends on DEBUG_KERNEL |
a304e1b8 DW |
610 | help |
611 | Enable this to generate a spurious interrupt as soon as a shared | |
612 | interrupt handler is registered, and just before one is deregistered. | |
613 | Drivers ought to be able to handle interrupts coming in at those | |
614 | points; some don't and need to be caught. | |
615 | ||
92aef8fb DH |
616 | menu "Debug Lockups and Hangs" |
617 | ||
58687acb DZ |
618 | config LOCKUP_DETECTOR |
619 | bool "Detect Hard and Soft Lockups" | |
dea20a3f | 620 | depends on DEBUG_KERNEL && !S390 |
8446f1d3 | 621 | help |
58687acb DZ |
622 | Say Y here to enable the kernel to act as a watchdog to detect |
623 | hard and soft lockups. | |
624 | ||
625 | Softlockups are bugs that cause the kernel to loop in kernel | |
5f329089 | 626 | mode for more than 20 seconds, without giving other tasks a |
58687acb DZ |
627 | chance to run. The current stack trace is displayed upon |
628 | detection and the system will stay locked up. | |
8446f1d3 | 629 | |
58687acb | 630 | Hardlockups are bugs that cause the CPU to loop in kernel mode |
5f329089 | 631 | for more than 10 seconds, without letting other interrupts have a |
58687acb DZ |
632 | chance to run. The current stack trace is displayed upon detection |
633 | and the system will stay locked up. | |
8446f1d3 | 634 | |
58687acb | 635 | The overhead should be minimal. A periodic hrtimer runs to |
5f329089 FLVC |
636 | generate interrupts and kick the watchdog task every 4 seconds. |
637 | An NMI is generated every 10 seconds or so to check for hardlockups. | |
638 | ||
639 | The frequency of hrtimer and NMI events and the soft and hard lockup | |
640 | thresholds can be controlled through the sysctl watchdog_thresh. | |
8446f1d3 | 641 | |
23637d47 | 642 | config HARDLOCKUP_DETECTOR |
8f1f66ed JB |
643 | def_bool y |
644 | depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG | |
645 | depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI | |
8446f1d3 | 646 | |
fef2c9bc DZ |
647 | config BOOTPARAM_HARDLOCKUP_PANIC |
648 | bool "Panic (Reboot) On Hard Lockups" | |
8f1f66ed | 649 | depends on HARDLOCKUP_DETECTOR |
fef2c9bc DZ |
650 | help |
651 | Say Y here to enable the kernel to panic on "hard lockups", | |
652 | which are bugs that cause the kernel to loop in kernel | |
5f329089 FLVC |
653 | mode with interrupts disabled for more than 10 seconds (configurable |
654 | using the watchdog_thresh sysctl). | |
fef2c9bc DZ |
655 | |
656 | Say N if unsure. | |
657 | ||
658 | config BOOTPARAM_HARDLOCKUP_PANIC_VALUE | |
659 | int | |
8f1f66ed | 660 | depends on HARDLOCKUP_DETECTOR |
fef2c9bc DZ |
661 | range 0 1 |
662 | default 0 if !BOOTPARAM_HARDLOCKUP_PANIC | |
663 | default 1 if BOOTPARAM_HARDLOCKUP_PANIC | |
664 | ||
9c44bc03 IM |
665 | config BOOTPARAM_SOFTLOCKUP_PANIC |
666 | bool "Panic (Reboot) On Soft Lockups" | |
89d7ce2a | 667 | depends on LOCKUP_DETECTOR |
9c44bc03 IM |
668 | help |
669 | Say Y here to enable the kernel to panic on "soft lockups", | |
670 | which are bugs that cause the kernel to loop in kernel | |
5f329089 FLVC |
671 | mode for more than 20 seconds (configurable using the watchdog_thresh |
672 | sysctl), without giving other tasks a chance to run. | |
9c44bc03 IM |
673 | |
674 | The panic can be used in combination with panic_timeout, | |
675 | to cause the system to reboot automatically after a | |
676 | lockup has been detected. This feature is useful for | |
677 | high-availability systems that have uptime guarantees and | |
678 | where a lockup must be resolved ASAP. | |
679 | ||
680 | Say N if unsure. | |
681 | ||
682 | config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE | |
683 | int | |
e16bb1d7 | 684 | depends on LOCKUP_DETECTOR |
9c44bc03 IM |
685 | range 0 1 |
686 | default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC | |
687 | default 1 if BOOTPARAM_SOFTLOCKUP_PANIC | |
688 | ||
e162b39a MSB |
689 | config DETECT_HUNG_TASK |
690 | bool "Detect Hung Tasks" | |
691 | depends on DEBUG_KERNEL | |
8edbb83e | 692 | default LOCKUP_DETECTOR |
e162b39a | 693 | help |
0610c8a8 DH |
694 | Say Y here to enable the kernel to detect "hung tasks", |
695 | which are bugs that cause the task to be stuck in | |
696 | uninterruptible "D" state indefinitiley. | |
1da177e4 | 697 | |
0610c8a8 DH |
698 | When a hung task is detected, the kernel will print the |
699 | current stack trace (which you should report), but the | |
700 | task will stay in uninterruptible state. If lockdep is | |
701 | enabled then all held locks will also be reported. This | |
702 | feature has negligible overhead. | |
871751e2 | 703 | |
0610c8a8 DH |
704 | config DEFAULT_HUNG_TASK_TIMEOUT |
705 | int "Default timeout for hung task detection (in seconds)" | |
706 | depends on DETECT_HUNG_TASK | |
707 | default 120 | |
f0630fff | 708 | help |
0610c8a8 DH |
709 | This option controls the default timeout (in seconds) used |
710 | to determine when a task has become non-responsive and should | |
711 | be considered hung. | |
f0630fff | 712 | |
0610c8a8 DH |
713 | It can be adjusted at runtime via the kernel.hung_task_timeout_secs |
714 | sysctl or by writing a value to | |
715 | /proc/sys/kernel/hung_task_timeout_secs. | |
8ff12cfc | 716 | |
0610c8a8 DH |
717 | A timeout of 0 disables the check. The default is two minutes. |
718 | Keeping the default should be fine in most cases. | |
b69ec42b | 719 | |
0610c8a8 DH |
720 | config BOOTPARAM_HUNG_TASK_PANIC |
721 | bool "Panic (Reboot) On Hung Tasks" | |
722 | depends on DETECT_HUNG_TASK | |
3bba00d7 | 723 | help |
0610c8a8 DH |
724 | Say Y here to enable the kernel to panic on "hung tasks", |
725 | which are bugs that cause the kernel to leave a task stuck | |
726 | in uninterruptible "D" state. | |
3bba00d7 | 727 | |
0610c8a8 DH |
728 | The panic can be used in combination with panic_timeout, |
729 | to cause the system to reboot automatically after a | |
730 | hung task has been detected. This feature is useful for | |
731 | high-availability systems that have uptime guarantees and | |
732 | where a hung tasks must be resolved ASAP. | |
bf96d1e3 | 733 | |
0610c8a8 | 734 | Say N if unsure. |
bf96d1e3 | 735 | |
0610c8a8 DH |
736 | config BOOTPARAM_HUNG_TASK_PANIC_VALUE |
737 | int | |
738 | depends on DETECT_HUNG_TASK | |
739 | range 0 1 | |
740 | default 0 if !BOOTPARAM_HUNG_TASK_PANIC | |
741 | default 1 if BOOTPARAM_HUNG_TASK_PANIC | |
3bba00d7 | 742 | |
92aef8fb DH |
743 | endmenu # "Debug lockups and hangs" |
744 | ||
745 | config PANIC_ON_OOPS | |
746 | bool "Panic on Oops" | |
a9d9058a | 747 | help |
92aef8fb DH |
748 | Say Y here to enable the kernel to panic when it oopses. This |
749 | has the same effect as setting oops=panic on the kernel command | |
750 | line. | |
a9d9058a | 751 | |
92aef8fb DH |
752 | This feature is useful to ensure that the kernel does not do |
753 | anything erroneous after an oops which could result in data | |
754 | corruption or other issues. | |
755 | ||
756 | Say N if unsure. | |
757 | ||
758 | config PANIC_ON_OOPS_VALUE | |
759 | int | |
760 | range 0 1 | |
761 | default 0 if !PANIC_ON_OOPS | |
762 | default 1 if PANIC_ON_OOPS | |
763 | ||
5800dc3c JB |
764 | config PANIC_TIMEOUT |
765 | int "panic timeout" | |
766 | default 0 | |
767 | help | |
768 | Set the timeout value (in seconds) until a reboot occurs when the | |
769 | the kernel panics. If n = 0, then we wait forever. A timeout | |
770 | value n > 0 will wait n seconds before rebooting, while a timeout | |
771 | value n < 0 will reboot immediately. | |
772 | ||
0610c8a8 DH |
773 | config SCHED_DEBUG |
774 | bool "Collect scheduler debugging info" | |
775 | depends on DEBUG_KERNEL && PROC_FS | |
776 | default y | |
0822ee4a | 777 | help |
0610c8a8 DH |
778 | If you say Y here, the /proc/sched_debug file will be provided |
779 | that can help debug the scheduler. The runtime overhead of this | |
780 | option is minimal. | |
0822ee4a | 781 | |
0610c8a8 DH |
782 | config SCHEDSTATS |
783 | bool "Collect scheduler statistics" | |
784 | depends on DEBUG_KERNEL && PROC_FS | |
785 | help | |
786 | If you say Y here, additional code will be inserted into the | |
787 | scheduler and related routines to collect statistics about | |
788 | scheduler behavior and provide them in /proc/schedstat. These | |
789 | stats may be useful for both tuning and debugging the scheduler | |
790 | If you aren't debugging the scheduler or trying to tune a specific | |
791 | application, you can say N to avoid the very slight overhead | |
792 | this adds. | |
0822ee4a | 793 | |
0610c8a8 DH |
794 | config TIMER_STATS |
795 | bool "Collect kernel timers statistics" | |
796 | depends on DEBUG_KERNEL && PROC_FS | |
ab0155a2 | 797 | help |
0610c8a8 DH |
798 | If you say Y here, additional code will be inserted into the |
799 | timer routines to collect statistics about kernel timers being | |
800 | reprogrammed. The statistics can be read from /proc/timer_stats. | |
801 | The statistics collection is started by writing 1 to /proc/timer_stats, | |
802 | writing 0 stops it. This feature is useful to collect information | |
803 | about timer usage patterns in kernel and userspace. This feature | |
804 | is lightweight if enabled in the kernel config but not activated | |
805 | (it defaults to deactivated on bootup and will only be activated | |
806 | if some application like powertop activates it explicitly). | |
ab0155a2 | 807 | |
1da177e4 LT |
808 | config DEBUG_PREEMPT |
809 | bool "Debug preemptible kernel" | |
01deab98 | 810 | depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT |
1da177e4 LT |
811 | default y |
812 | help | |
813 | If you say Y here then the kernel will use a debug variant of the | |
814 | commonly used smp_processor_id() function and will print warnings | |
815 | if kernel code uses it in a preemption-unsafe way. Also, the kernel | |
816 | will detect preemption count underflows. | |
817 | ||
9eade16b DH |
818 | menu "Lock Debugging (spinlocks, mutexes, etc...)" |
819 | ||
e7eebaf6 IM |
820 | config DEBUG_RT_MUTEXES |
821 | bool "RT Mutex debugging, deadlock detection" | |
e7eebaf6 IM |
822 | depends on DEBUG_KERNEL && RT_MUTEXES |
823 | help | |
824 | This allows rt mutex semantics violations and rt mutex related | |
825 | deadlocks (lockups) to be detected and reported automatically. | |
826 | ||
827 | config DEBUG_PI_LIST | |
828 | bool | |
829 | default y | |
830 | depends on DEBUG_RT_MUTEXES | |
831 | ||
61a87122 TG |
832 | config RT_MUTEX_TESTER |
833 | bool "Built-in scriptable tester for rt-mutexes" | |
a1583d3e | 834 | depends on DEBUG_KERNEL && RT_MUTEXES |
61a87122 TG |
835 | help |
836 | This option enables a rt-mutex tester. | |
837 | ||
1da177e4 | 838 | config DEBUG_SPINLOCK |
4d9f34ad | 839 | bool "Spinlock and rw-lock debugging: basic checks" |
1da177e4 | 840 | depends on DEBUG_KERNEL |
e335e3eb | 841 | select UNINLINE_SPIN_UNLOCK |
1da177e4 LT |
842 | help |
843 | Say Y here and build SMP to catch missing spinlock initialization | |
844 | and certain other kinds of spinlock errors commonly made. This is | |
845 | best used in conjunction with the NMI watchdog so that spinlock | |
846 | deadlocks are also debuggable. | |
847 | ||
4d9f34ad IM |
848 | config DEBUG_MUTEXES |
849 | bool "Mutex debugging: basic checks" | |
850 | depends on DEBUG_KERNEL | |
851 | help | |
852 | This feature allows mutex semantics violations to be detected and | |
853 | reported. | |
854 | ||
23010027 SV |
855 | config DEBUG_WW_MUTEX_SLOWPATH |
856 | bool "Wait/wound mutex debugging: Slowpath testing" | |
857 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT | |
858 | select DEBUG_LOCK_ALLOC | |
859 | select DEBUG_SPINLOCK | |
860 | select DEBUG_MUTEXES | |
861 | help | |
862 | This feature enables slowpath testing for w/w mutex users by | |
863 | injecting additional -EDEADLK wound/backoff cases. Together with | |
864 | the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this | |
865 | will test all possible w/w mutex interface abuse with the | |
866 | exception of simply not acquiring all the required locks. | |
867 | ||
4d9f34ad IM |
868 | config DEBUG_LOCK_ALLOC |
869 | bool "Lock debugging: detect incorrect freeing of live locks" | |
517e7aa5 | 870 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
871 | select DEBUG_SPINLOCK |
872 | select DEBUG_MUTEXES | |
4d9f34ad IM |
873 | select LOCKDEP |
874 | help | |
875 | This feature will check whether any held lock (spinlock, rwlock, | |
876 | mutex or rwsem) is incorrectly freed by the kernel, via any of the | |
877 | memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), | |
878 | vfree(), etc.), whether a live lock is incorrectly reinitialized via | |
879 | spin_lock_init()/mutex_init()/etc., or whether there is any lock | |
880 | held during task exit. | |
881 | ||
882 | config PROVE_LOCKING | |
883 | bool "Lock debugging: prove locking correctness" | |
517e7aa5 | 884 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
885 | select LOCKDEP |
886 | select DEBUG_SPINLOCK | |
887 | select DEBUG_MUTEXES | |
4d9f34ad | 888 | select DEBUG_LOCK_ALLOC |
46b93b74 | 889 | select TRACE_IRQFLAGS |
4d9f34ad IM |
890 | default n |
891 | help | |
892 | This feature enables the kernel to prove that all locking | |
893 | that occurs in the kernel runtime is mathematically | |
894 | correct: that under no circumstance could an arbitrary (and | |
895 | not yet triggered) combination of observed locking | |
896 | sequences (on an arbitrary number of CPUs, running an | |
897 | arbitrary number of tasks and interrupt contexts) cause a | |
898 | deadlock. | |
899 | ||
900 | In short, this feature enables the kernel to report locking | |
901 | related deadlocks before they actually occur. | |
902 | ||
903 | The proof does not depend on how hard and complex a | |
904 | deadlock scenario would be to trigger: how many | |
905 | participant CPUs, tasks and irq-contexts would be needed | |
906 | for it to trigger. The proof also does not depend on | |
907 | timing: if a race and a resulting deadlock is possible | |
908 | theoretically (no matter how unlikely the race scenario | |
909 | is), it will be proven so and will immediately be | |
910 | reported by the kernel (once the event is observed that | |
911 | makes the deadlock theoretically possible). | |
912 | ||
913 | If a deadlock is impossible (i.e. the locking rules, as | |
914 | observed by the kernel, are mathematically correct), the | |
915 | kernel reports nothing. | |
916 | ||
917 | NOTE: this feature can also be enabled for rwlocks, mutexes | |
918 | and rwsems - in which case all dependencies between these | |
919 | different locking variants are observed and mapped too, and | |
920 | the proof of observed correctness is also maintained for an | |
921 | arbitrary combination of these separate locking variants. | |
922 | ||
923 | For more details, see Documentation/lockdep-design.txt. | |
924 | ||
925 | config LOCKDEP | |
926 | bool | |
517e7aa5 | 927 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad | 928 | select STACKTRACE |
cc80ae38 | 929 | select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC |
4d9f34ad IM |
930 | select KALLSYMS |
931 | select KALLSYMS_ALL | |
932 | ||
f20786ff | 933 | config LOCK_STAT |
fdfb870f | 934 | bool "Lock usage statistics" |
f20786ff PZ |
935 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
936 | select LOCKDEP | |
937 | select DEBUG_SPINLOCK | |
938 | select DEBUG_MUTEXES | |
939 | select DEBUG_LOCK_ALLOC | |
940 | default n | |
941 | help | |
942 | This feature enables tracking lock contention points | |
943 | ||
a560aa48 PZ |
944 | For more details, see Documentation/lockstat.txt |
945 | ||
dd8b1cf6 FW |
946 | This also enables lock events required by "perf lock", |
947 | subcommand of perf. | |
948 | If you want to use "perf lock", you also need to turn on | |
949 | CONFIG_EVENT_TRACING. | |
84c6f88f HM |
950 | |
951 | CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. | |
dd8b1cf6 | 952 | (CONFIG_LOCKDEP defines "acquire" and "release" events.) |
84c6f88f | 953 | |
4d9f34ad IM |
954 | config DEBUG_LOCKDEP |
955 | bool "Lock dependency engine debugging" | |
517e7aa5 | 956 | depends on DEBUG_KERNEL && LOCKDEP |
4d9f34ad IM |
957 | help |
958 | If you say Y here, the lock dependency engine will do | |
959 | additional runtime checks to debug itself, at the price | |
960 | of more runtime overhead. | |
961 | ||
d902db1e FW |
962 | config DEBUG_ATOMIC_SLEEP |
963 | bool "Sleep inside atomic section checking" | |
e8f7c70f | 964 | select PREEMPT_COUNT |
1da177e4 LT |
965 | depends on DEBUG_KERNEL |
966 | help | |
967 | If you say Y here, various routines which may sleep will become very | |
d902db1e FW |
968 | noisy if they are called inside atomic sections: when a spinlock is |
969 | held, inside an rcu read side critical section, inside preempt disabled | |
970 | sections, inside an interrupt, etc... | |
1da177e4 | 971 | |
cae2ed9a IM |
972 | config DEBUG_LOCKING_API_SELFTESTS |
973 | bool "Locking API boot-time self-tests" | |
974 | depends on DEBUG_KERNEL | |
975 | help | |
976 | Say Y here if you want the kernel to run a short self-test during | |
977 | bootup. The self-test checks whether common types of locking bugs | |
978 | are detected by debugging mechanisms or not. (if you disable | |
979 | lock debugging then those bugs wont be detected of course.) | |
980 | The following locking APIs are covered: spinlocks, rwlocks, | |
981 | mutexes and rwsems. | |
982 | ||
9eade16b | 983 | endmenu # lock debugging |
8637c099 | 984 | |
9eade16b DH |
985 | config TRACE_IRQFLAGS |
986 | bool | |
5ca43f6c | 987 | help |
9eade16b DH |
988 | Enables hooks to interrupt enabling and disabling for |
989 | either tracing or lock debugging. | |
5ca43f6c | 990 | |
8637c099 IM |
991 | config STACKTRACE |
992 | bool | |
993 | depends on STACKTRACE_SUPPORT | |
5ca43f6c | 994 | |
1da177e4 LT |
995 | config DEBUG_KOBJECT |
996 | bool "kobject debugging" | |
997 | depends on DEBUG_KERNEL | |
998 | help | |
999 | If you say Y here, some extra kobject debugging messages will be sent | |
1000 | to the syslog. | |
1001 | ||
c817a67e RK |
1002 | config DEBUG_KOBJECT_RELEASE |
1003 | bool "kobject release debugging" | |
2a999aa0 | 1004 | depends on DEBUG_OBJECTS_TIMERS |
c817a67e RK |
1005 | help |
1006 | kobjects are reference counted objects. This means that their | |
1007 | last reference count put is not predictable, and the kobject can | |
1008 | live on past the point at which a driver decides to drop it's | |
1009 | initial reference to the kobject gained on allocation. An | |
1010 | example of this would be a struct device which has just been | |
1011 | unregistered. | |
1012 | ||
1013 | However, some buggy drivers assume that after such an operation, | |
1014 | the memory backing the kobject can be immediately freed. This | |
1015 | goes completely against the principles of a refcounted object. | |
1016 | ||
1017 | If you say Y here, the kernel will delay the release of kobjects | |
1018 | on the last reference count to improve the visibility of this | |
1019 | kind of kobject release bug. | |
1020 | ||
9b2a60c4 CM |
1021 | config HAVE_DEBUG_BUGVERBOSE |
1022 | bool | |
1023 | ||
1da177e4 | 1024 | config DEBUG_BUGVERBOSE |
6a108a14 | 1025 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT |
9b2a60c4 | 1026 | depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE) |
8420e7ef | 1027 | default y |
1da177e4 LT |
1028 | help |
1029 | Say Y here to make BUG() panics output the file name and line number | |
1030 | of the BUG call as well as the EIP and oops trace. This aids | |
1031 | debugging but costs about 70-100K of memory. | |
1032 | ||
ad775f5a DH |
1033 | config DEBUG_WRITECOUNT |
1034 | bool "Debug filesystem writers count" | |
1035 | depends on DEBUG_KERNEL | |
1036 | help | |
1037 | Enable this to catch wrong use of the writers count in struct | |
1038 | vfsmount. This will increase the size of each file struct by | |
1039 | 32 bits. | |
1040 | ||
1041 | If unsure, say N. | |
1042 | ||
199a9afc DJ |
1043 | config DEBUG_LIST |
1044 | bool "Debug linked list manipulation" | |
1045 | depends on DEBUG_KERNEL | |
1046 | help | |
1047 | Enable this to turn on extended checks in the linked-list | |
1048 | walking routines. | |
1049 | ||
1050 | If unsure, say N. | |
1051 | ||
d6ec0842 JA |
1052 | config DEBUG_SG |
1053 | bool "Debug SG table operations" | |
1054 | depends on DEBUG_KERNEL | |
1055 | help | |
1056 | Enable this to turn on checks on scatter-gather tables. This can | |
1057 | help find problems with drivers that do not properly initialize | |
1058 | their sg tables. | |
1059 | ||
1060 | If unsure, say N. | |
1061 | ||
1b2439db AV |
1062 | config DEBUG_NOTIFIERS |
1063 | bool "Debug notifier call chains" | |
1064 | depends on DEBUG_KERNEL | |
1065 | help | |
1066 | Enable this to turn on sanity checking for notifier call chains. | |
1067 | This is most useful for kernel developers to make sure that | |
1068 | modules properly unregister themselves from notifier chains. | |
1069 | This is a relatively cheap check but if you care about maximum | |
1070 | performance, say N. | |
1071 | ||
e0e81739 DH |
1072 | config DEBUG_CREDENTIALS |
1073 | bool "Debug credential management" | |
1074 | depends on DEBUG_KERNEL | |
1075 | help | |
1076 | Enable this to turn on some debug checking for credential | |
1077 | management. The additional code keeps track of the number of | |
1078 | pointers from task_structs to any given cred struct, and checks to | |
1079 | see that this number never exceeds the usage count of the cred | |
1080 | struct. | |
1081 | ||
1082 | Furthermore, if SELinux is enabled, this also checks that the | |
1083 | security pointer in the cred struct is never seen to be invalid. | |
1084 | ||
1085 | If unsure, say N. | |
1086 | ||
2f03e3ca DH |
1087 | menu "RCU Debugging" |
1088 | ||
1089 | config PROVE_RCU | |
1090 | bool "RCU debugging: prove RCU correctness" | |
1091 | depends on PROVE_LOCKING | |
1092 | default n | |
1093 | help | |
1094 | This feature enables lockdep extensions that check for correct | |
1095 | use of RCU APIs. This is currently under development. Say Y | |
1096 | if you want to debug RCU usage or help work on the PROVE_RCU | |
1097 | feature. | |
1098 | ||
1099 | Say N if you are unsure. | |
1100 | ||
1101 | config PROVE_RCU_REPEATEDLY | |
1102 | bool "RCU debugging: don't disable PROVE_RCU on first splat" | |
1103 | depends on PROVE_RCU | |
1104 | default n | |
1105 | help | |
1106 | By itself, PROVE_RCU will disable checking upon issuing the | |
1107 | first warning (or "splat"). This feature prevents such | |
1108 | disabling, allowing multiple RCU-lockdep warnings to be printed | |
1109 | on a single reboot. | |
1110 | ||
1111 | Say Y to allow multiple RCU-lockdep warnings per boot. | |
1112 | ||
1113 | Say N if you are unsure. | |
1114 | ||
1115 | config PROVE_RCU_DELAY | |
1116 | bool "RCU debugging: preemptible RCU race provocation" | |
1117 | depends on DEBUG_KERNEL && PREEMPT_RCU | |
1118 | default n | |
1119 | help | |
1120 | There is a class of races that involve an unlikely preemption | |
1121 | of __rcu_read_unlock() just after ->rcu_read_lock_nesting has | |
1122 | been set to INT_MIN. This feature inserts a delay at that | |
1123 | point to increase the probability of these races. | |
1124 | ||
1125 | Say Y to increase probability of preemption of __rcu_read_unlock(). | |
1126 | ||
1127 | Say N if you are unsure. | |
1128 | ||
1129 | config SPARSE_RCU_POINTER | |
1130 | bool "RCU debugging: sparse-based checks for pointer usage" | |
1131 | default n | |
1132 | help | |
1133 | This feature enables the __rcu sparse annotation for | |
1134 | RCU-protected pointers. This annotation will cause sparse | |
1135 | to flag any non-RCU used of annotated pointers. This can be | |
1136 | helpful when debugging RCU usage. Please note that this feature | |
1137 | is not intended to enforce code cleanliness; it is instead merely | |
1138 | a debugging aid. | |
1139 | ||
1140 | Say Y to make sparse flag questionable use of RCU-protected pointers | |
1141 | ||
1142 | Say N if you are unsure. | |
1143 | ||
a241ec65 PM |
1144 | config RCU_TORTURE_TEST |
1145 | tristate "torture tests for RCU" | |
1146 | depends on DEBUG_KERNEL | |
1147 | default n | |
1148 | help | |
1149 | This option provides a kernel module that runs torture tests | |
1150 | on the RCU infrastructure. The kernel module may be built | |
1151 | after the fact on the running kernel to be tested, if desired. | |
1152 | ||
31a72bce PM |
1153 | Say Y here if you want RCU torture tests to be built into |
1154 | the kernel. | |
a241ec65 PM |
1155 | Say M if you want the RCU torture tests to build as a module. |
1156 | Say N if you are unsure. | |
8bb31b9d | 1157 | |
31a72bce PM |
1158 | config RCU_TORTURE_TEST_RUNNABLE |
1159 | bool "torture tests for RCU runnable by default" | |
1160 | depends on RCU_TORTURE_TEST = y | |
1161 | default n | |
1162 | help | |
1163 | This option provides a way to build the RCU torture tests | |
1164 | directly into the kernel without them starting up at boot | |
1165 | time. You can use /proc/sys/kernel/rcutorture_runnable | |
1166 | to manually override this setting. This /proc file is | |
1167 | available only when the RCU torture tests have been built | |
1168 | into the kernel. | |
1169 | ||
1170 | Say Y here if you want the RCU torture tests to start during | |
1171 | boot (you probably don't). | |
1172 | Say N here if you want the RCU torture tests to start only | |
1173 | after being manually enabled via /proc. | |
1174 | ||
b163760e PM |
1175 | config RCU_CPU_STALL_TIMEOUT |
1176 | int "RCU CPU stall timeout in seconds" | |
6bfc09e2 | 1177 | depends on RCU_STALL_COMMON |
b163760e | 1178 | range 3 300 |
c896054f | 1179 | default 21 |
b163760e PM |
1180 | help |
1181 | If a given RCU grace period extends more than the specified | |
1182 | number of seconds, a CPU stall warning is printed. If the | |
1183 | RCU grace period persists, additional CPU stall warnings are | |
1184 | printed at more widely spaced intervals. | |
1185 | ||
1ed509a2 PM |
1186 | config RCU_CPU_STALL_VERBOSE |
1187 | bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR" | |
a00e0d71 | 1188 | depends on TREE_PREEMPT_RCU |
55ec936f | 1189 | default y |
1ed509a2 PM |
1190 | help |
1191 | This option causes RCU to printk detailed per-task information | |
1192 | for any tasks that are stalling the current RCU grace period. | |
67182ae1 PM |
1193 | |
1194 | Say N if you are unsure. | |
1195 | ||
1ed509a2 PM |
1196 | Say Y if you want to enable such checks. |
1197 | ||
a858af28 PM |
1198 | config RCU_CPU_STALL_INFO |
1199 | bool "Print additional diagnostics on RCU CPU stall" | |
1200 | depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL | |
1201 | default n | |
1202 | help | |
1203 | For each stalled CPU that is aware of the current RCU grace | |
1204 | period, print out additional per-CPU diagnostic information | |
1205 | regarding scheduling-clock ticks, idle state, and, | |
1206 | for RCU_FAST_NO_HZ kernels, idle-entry state. | |
1207 | ||
1208 | Say N if you are unsure. | |
1209 | ||
1210 | Say Y if you want to enable such diagnostics. | |
1211 | ||
5c8806a0 PM |
1212 | config RCU_TRACE |
1213 | bool "Enable tracing for RCU" | |
6dab2778 | 1214 | depends on DEBUG_KERNEL |
52494535 | 1215 | select TRACE_CLOCK |
6dab2778 | 1216 | help |
5c8806a0 PM |
1217 | This option provides tracing in RCU which presents stats |
1218 | in debugfs for debugging RCU implementation. | |
ad118c54 | 1219 | |
5c8806a0 | 1220 | Say Y here if you want to enable RCU tracing |
6dab2778 AV |
1221 | Say N if you are unsure. |
1222 | ||
2f03e3ca DH |
1223 | endmenu # "RCU Debugging" |
1224 | ||
870d6656 TH |
1225 | config DEBUG_BLOCK_EXT_DEVT |
1226 | bool "Force extended block device numbers and spread them" | |
1227 | depends on DEBUG_KERNEL | |
1228 | depends on BLOCK | |
759f8ca3 | 1229 | default n |
870d6656 | 1230 | help |
0e11e342 TH |
1231 | BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON |
1232 | SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT | |
1233 | YOU ARE DOING. Distros, please enable this and fix whatever | |
1234 | is broken. | |
1235 | ||
870d6656 TH |
1236 | Conventionally, block device numbers are allocated from |
1237 | predetermined contiguous area. However, extended block area | |
1238 | may introduce non-contiguous block device numbers. This | |
1239 | option forces most block device numbers to be allocated from | |
1240 | the extended space and spreads them to discover kernel or | |
1241 | userland code paths which assume predetermined contiguous | |
1242 | device number allocation. | |
1243 | ||
55dc7db7 TH |
1244 | Note that turning on this debug option shuffles all the |
1245 | device numbers for all IDE and SCSI devices including libata | |
1246 | ones, so root partition specified using device number | |
1247 | directly (via rdev or root=MAJ:MIN) won't work anymore. | |
1248 | Textual device names (root=/dev/sdXn) will continue to work. | |
1249 | ||
870d6656 TH |
1250 | Say N if you are unsure. |
1251 | ||
8d438288 AM |
1252 | config NOTIFIER_ERROR_INJECTION |
1253 | tristate "Notifier error injection" | |
1254 | depends on DEBUG_KERNEL | |
1255 | select DEBUG_FS | |
1256 | help | |
e41e85cc | 1257 | This option provides the ability to inject artificial errors to |
8d438288 AM |
1258 | specified notifier chain callbacks. It is useful to test the error |
1259 | handling of notifier call chain failures. | |
1260 | ||
1261 | Say N if unsure. | |
1262 | ||
c9d221f8 AM |
1263 | config CPU_NOTIFIER_ERROR_INJECT |
1264 | tristate "CPU notifier error injection module" | |
f5a9f52e | 1265 | depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION |
c9d221f8 AM |
1266 | help |
1267 | This option provides a kernel module that can be used to test | |
e41e85cc | 1268 | the error handling of the cpu notifiers by injecting artificial |
f5a9f52e AM |
1269 | errors to CPU notifier chain callbacks. It is controlled through |
1270 | debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu | |
1271 | ||
1272 | If the notifier call chain should be failed with some events | |
1273 | notified, write the error code to "actions/<notifier event>/error". | |
1274 | ||
1275 | Example: Inject CPU offline error (-1 == -EPERM) | |
1276 | ||
1277 | # cd /sys/kernel/debug/notifier-error-inject/cpu | |
1278 | # echo -1 > actions/CPU_DOWN_PREPARE/error | |
1279 | # echo 0 > /sys/devices/system/cpu/cpu1/online | |
1280 | bash: echo: write error: Operation not permitted | |
c9d221f8 AM |
1281 | |
1282 | To compile this code as a module, choose M here: the module will | |
1283 | be called cpu-notifier-error-inject. | |
1284 | ||
1285 | If unsure, say N. | |
1286 | ||
048b9c35 AM |
1287 | config PM_NOTIFIER_ERROR_INJECT |
1288 | tristate "PM notifier error injection module" | |
1289 | depends on PM && NOTIFIER_ERROR_INJECTION | |
1290 | default m if PM_DEBUG | |
1291 | help | |
e41e85cc | 1292 | This option provides the ability to inject artificial errors to |
048b9c35 AM |
1293 | PM notifier chain callbacks. It is controlled through debugfs |
1294 | interface /sys/kernel/debug/notifier-error-inject/pm | |
1295 | ||
1296 | If the notifier call chain should be failed with some events | |
1297 | notified, write the error code to "actions/<notifier event>/error". | |
1298 | ||
1299 | Example: Inject PM suspend error (-12 = -ENOMEM) | |
1300 | ||
1301 | # cd /sys/kernel/debug/notifier-error-inject/pm/ | |
1302 | # echo -12 > actions/PM_SUSPEND_PREPARE/error | |
1303 | # echo mem > /sys/power/state | |
1304 | bash: echo: write error: Cannot allocate memory | |
1305 | ||
1306 | To compile this code as a module, choose M here: the module will | |
1307 | be called pm-notifier-error-inject. | |
1308 | ||
1309 | If unsure, say N. | |
1310 | ||
d526e85f BH |
1311 | config OF_RECONFIG_NOTIFIER_ERROR_INJECT |
1312 | tristate "OF reconfig notifier error injection module" | |
1313 | depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION | |
08dfb4dd | 1314 | help |
e41e85cc | 1315 | This option provides the ability to inject artificial errors to |
d526e85f | 1316 | OF reconfig notifier chain callbacks. It is controlled |
08dfb4dd | 1317 | through debugfs interface under |
d526e85f | 1318 | /sys/kernel/debug/notifier-error-inject/OF-reconfig/ |
08dfb4dd AM |
1319 | |
1320 | If the notifier call chain should be failed with some events | |
1321 | notified, write the error code to "actions/<notifier event>/error". | |
1322 | ||
1323 | To compile this code as a module, choose M here: the module will | |
e12a95f4 | 1324 | be called of-reconfig-notifier-error-inject. |
08dfb4dd AM |
1325 | |
1326 | If unsure, say N. | |
1327 | ||
6ff1cb35 | 1328 | config FAULT_INJECTION |
1ab8509a AM |
1329 | bool "Fault-injection framework" |
1330 | depends on DEBUG_KERNEL | |
329409ae AM |
1331 | help |
1332 | Provide fault-injection framework. | |
1333 | For more details, see Documentation/fault-injection/. | |
6ff1cb35 | 1334 | |
8a8b6502 | 1335 | config FAILSLAB |
1ab8509a AM |
1336 | bool "Fault-injection capability for kmalloc" |
1337 | depends on FAULT_INJECTION | |
773ff60e | 1338 | depends on SLAB || SLUB |
8a8b6502 | 1339 | help |
1ab8509a | 1340 | Provide fault-injection capability for kmalloc. |
8a8b6502 | 1341 | |
933e312e AM |
1342 | config FAIL_PAGE_ALLOC |
1343 | bool "Fault-injection capabilitiy for alloc_pages()" | |
1ab8509a | 1344 | depends on FAULT_INJECTION |
933e312e | 1345 | help |
1ab8509a | 1346 | Provide fault-injection capability for alloc_pages(). |
933e312e | 1347 | |
c17bb495 | 1348 | config FAIL_MAKE_REQUEST |
86327d19 | 1349 | bool "Fault-injection capability for disk IO" |
581d4e28 | 1350 | depends on FAULT_INJECTION && BLOCK |
c17bb495 | 1351 | help |
1ab8509a | 1352 | Provide fault-injection capability for disk IO. |
c17bb495 | 1353 | |
581d4e28 | 1354 | config FAIL_IO_TIMEOUT |
f4d01439 | 1355 | bool "Fault-injection capability for faking disk interrupts" |
581d4e28 JA |
1356 | depends on FAULT_INJECTION && BLOCK |
1357 | help | |
1358 | Provide fault-injection capability on end IO handling. This | |
1359 | will make the block layer "forget" an interrupt as configured, | |
1360 | thus exercising the error handling. | |
1361 | ||
1362 | Only works with drivers that use the generic timeout handling, | |
1363 | for others it wont do anything. | |
1364 | ||
1b676f70 PF |
1365 | config FAIL_MMC_REQUEST |
1366 | bool "Fault-injection capability for MMC IO" | |
1367 | select DEBUG_FS | |
1368 | depends on FAULT_INJECTION && MMC | |
1369 | help | |
1370 | Provide fault-injection capability for MMC IO. | |
1371 | This will make the mmc core return data errors. This is | |
1372 | useful to test the error handling in the mmc block device | |
1373 | and to test how the mmc host driver handles retries from | |
1374 | the block device. | |
1375 | ||
6ff1cb35 AM |
1376 | config FAULT_INJECTION_DEBUG_FS |
1377 | bool "Debugfs entries for fault-injection capabilities" | |
1ab8509a | 1378 | depends on FAULT_INJECTION && SYSFS && DEBUG_FS |
6ff1cb35 | 1379 | help |
1ab8509a | 1380 | Enable configuration of fault-injection capabilities via debugfs. |
1df49008 AM |
1381 | |
1382 | config FAULT_INJECTION_STACKTRACE_FILTER | |
1383 | bool "stacktrace filter for fault-injection capabilities" | |
1384 | depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT | |
6d690dca | 1385 | depends on !X86_64 |
1df49008 | 1386 | select STACKTRACE |
cc80ae38 | 1387 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC |
1df49008 AM |
1388 | help |
1389 | Provide stacktrace filter for fault-injection capabilities | |
267c4025 | 1390 | |
9745512c AV |
1391 | config LATENCYTOP |
1392 | bool "Latency measuring infrastructure" | |
625fdcaa RD |
1393 | depends on HAVE_LATENCYTOP_SUPPORT |
1394 | depends on DEBUG_KERNEL | |
1395 | depends on STACKTRACE_SUPPORT | |
1396 | depends on PROC_FS | |
cc80ae38 | 1397 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC |
9745512c AV |
1398 | select KALLSYMS |
1399 | select KALLSYMS_ALL | |
1400 | select STACKTRACE | |
1401 | select SCHEDSTATS | |
1402 | select SCHED_DEBUG | |
9745512c AV |
1403 | help |
1404 | Enable this option if you want to use the LatencyTOP tool | |
1405 | to find out which userspace is blocking on what kernel operations. | |
1406 | ||
446f24d1 SB |
1407 | config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS |
1408 | bool | |
1409 | ||
1410 | config DEBUG_STRICT_USER_COPY_CHECKS | |
1411 | bool "Strict user copy size checks" | |
1412 | depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS | |
1413 | depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING | |
1414 | help | |
1415 | Enabling this option turns a certain set of sanity checks for user | |
1416 | copy operations into compile time failures. | |
1417 | ||
1418 | The copy_from_user() etc checks are there to help test if there | |
1419 | are sufficient security checks on the length argument of | |
1420 | the copy operation, by having gcc prove that the argument is | |
1421 | within bounds. | |
1422 | ||
1423 | If unsure, say N. | |
1424 | ||
16444a8a ACM |
1425 | source kernel/trace/Kconfig |
1426 | ||
881c5149 DH |
1427 | menu "Runtime Testing" |
1428 | ||
1429 | config LKDTM | |
1430 | tristate "Linux Kernel Dump Test Tool Module" | |
1431 | depends on DEBUG_FS | |
1432 | depends on BLOCK | |
1433 | default n | |
1434 | help | |
1435 | This module enables testing of the different dumping mechanisms by | |
1436 | inducing system failures at predefined crash points. | |
1437 | If you don't need it: say N | |
1438 | Choose M here to compile this code as a module. The module will be | |
1439 | called lkdtm. | |
1440 | ||
1441 | Documentation on how to use the module can be found in | |
1442 | Documentation/fault-injection/provoke-crashes.txt | |
1443 | ||
1444 | config TEST_LIST_SORT | |
1445 | bool "Linked list sorting test" | |
1446 | depends on DEBUG_KERNEL | |
1447 | help | |
1448 | Enable this to turn on 'list_sort()' function test. This test is | |
1449 | executed only once during system boot, so affects only boot time. | |
1450 | ||
1451 | If unsure, say N. | |
1452 | ||
1453 | config KPROBES_SANITY_TEST | |
1454 | bool "Kprobes sanity tests" | |
1455 | depends on DEBUG_KERNEL | |
1456 | depends on KPROBES | |
1457 | default n | |
1458 | help | |
1459 | This option provides for testing basic kprobes functionality on | |
1460 | boot. A sample kprobe, jprobe and kretprobe are inserted and | |
1461 | verified for functionality. | |
1462 | ||
1463 | Say N if you are unsure. | |
1464 | ||
1465 | config BACKTRACE_SELF_TEST | |
1466 | tristate "Self test for the backtrace code" | |
1467 | depends on DEBUG_KERNEL | |
1468 | default n | |
1469 | help | |
1470 | This option provides a kernel module that can be used to test | |
1471 | the kernel stack backtrace code. This option is not useful | |
1472 | for distributions or general kernels, but only for kernel | |
1473 | developers working on architecture code. | |
1474 | ||
1475 | Note that if you want to also test saved backtraces, you will | |
1476 | have to enable STACKTRACE as well. | |
1477 | ||
1478 | Say N if you are unsure. | |
1479 | ||
910a742d ML |
1480 | config RBTREE_TEST |
1481 | tristate "Red-Black tree test" | |
7c993e11 | 1482 | depends on DEBUG_KERNEL |
910a742d ML |
1483 | help |
1484 | A benchmark measuring the performance of the rbtree library. | |
1485 | Also includes rbtree invariant checks. | |
1486 | ||
fff3fd8a ML |
1487 | config INTERVAL_TREE_TEST |
1488 | tristate "Interval tree test" | |
1489 | depends on m && DEBUG_KERNEL | |
1490 | help | |
1491 | A benchmark measuring the performance of the interval tree library | |
1492 | ||
623fd807 GT |
1493 | config PERCPU_TEST |
1494 | tristate "Per cpu operations test" | |
1495 | depends on m && DEBUG_KERNEL | |
1496 | help | |
1497 | Enable this option to build test module which validates per-cpu | |
1498 | operations. | |
1499 | ||
1500 | If unsure, say N. | |
1501 | ||
881c5149 DH |
1502 | config ATOMIC64_SELFTEST |
1503 | bool "Perform an atomic64_t self-test at boot" | |
1504 | help | |
1505 | Enable this option to test the atomic64_t functions at boot. | |
1506 | ||
1507 | If unsure, say N. | |
1508 | ||
1509 | config ASYNC_RAID6_TEST | |
1510 | tristate "Self test for hardware accelerated raid6 recovery" | |
1511 | depends on ASYNC_RAID6_RECOV | |
1512 | select ASYNC_MEMCPY | |
1513 | ---help--- | |
1514 | This is a one-shot self test that permutes through the | |
1515 | recovery of all the possible two disk failure scenarios for a | |
1516 | N-disk array. Recovery is performed with the asynchronous | |
1517 | raid6 recovery routines, and will optionally use an offload | |
1518 | engine if one is available. | |
1519 | ||
1520 | If unsure, say N. | |
1521 | ||
1522 | config TEST_STRING_HELPERS | |
1523 | tristate "Test functions located in the string_helpers module at runtime" | |
1524 | ||
1525 | config TEST_KSTRTOX | |
1526 | tristate "Test kstrto*() family of functions at runtime" | |
1527 | ||
1528 | endmenu # runtime tests | |
1529 | ||
f212ec4b | 1530 | config PROVIDE_OHCI1394_DMA_INIT |
080de8c2 | 1531 | bool "Remote debugging over FireWire early on boot" |
f212ec4b BK |
1532 | depends on PCI && X86 |
1533 | help | |
1534 | If you want to debug problems which hang or crash the kernel early | |
1535 | on boot and the crashing machine has a FireWire port, you can use | |
1536 | this feature to remotely access the memory of the crashed machine | |
1537 | over FireWire. This employs remote DMA as part of the OHCI1394 | |
1538 | specification which is now the standard for FireWire controllers. | |
1539 | ||
1540 | With remote DMA, you can monitor the printk buffer remotely using | |
1541 | firescope and access all memory below 4GB using fireproxy from gdb. | |
1542 | Even controlling a kernel debugger is possible using remote DMA. | |
1543 | ||
1544 | Usage: | |
1545 | ||
1546 | If ohci1394_dma=early is used as boot parameter, it will initialize | |
1547 | all OHCI1394 controllers which are found in the PCI config space. | |
1548 | ||
1549 | As all changes to the FireWire bus such as enabling and disabling | |
1550 | devices cause a bus reset and thereby disable remote DMA for all | |
1551 | devices, be sure to have the cable plugged and FireWire enabled on | |
1552 | the debugging host before booting the debug target for debugging. | |
1553 | ||
1554 | This code (~1k) is freed after boot. By then, the firewire stack | |
1555 | in charge of the OHCI-1394 controllers should be used instead. | |
1556 | ||
1557 | See Documentation/debugging-via-ohci1394.txt for more information. | |
9745512c | 1558 | |
080de8c2 SR |
1559 | config FIREWIRE_OHCI_REMOTE_DMA |
1560 | bool "Remote debugging over FireWire with firewire-ohci" | |
1561 | depends on FIREWIRE_OHCI | |
1562 | help | |
1563 | This option lets you use the FireWire bus for remote debugging | |
1564 | with help of the firewire-ohci driver. It enables unfiltered | |
1565 | remote DMA in firewire-ohci. | |
1566 | See Documentation/debugging-via-ohci1394.txt for more information. | |
1567 | ||
1568 | If unsure, say N. | |
1569 | ||
152de30b | 1570 | config BUILD_DOCSRC |
3794f3e8 RD |
1571 | bool "Build targets in Documentation/ tree" |
1572 | depends on HEADERS_CHECK | |
1573 | help | |
1574 | This option attempts to build objects from the source files in the | |
1575 | kernel Documentation/ tree. | |
1576 | ||
1577 | Say N if you are unsure. | |
1578 | ||
5ee00bd4 JR |
1579 | config DMA_API_DEBUG |
1580 | bool "Enable debugging of DMA-API usage" | |
1581 | depends on HAVE_DMA_API_DEBUG | |
1582 | help | |
1583 | Enable this option to debug the use of the DMA API by device drivers. | |
1584 | With this option you will be able to detect common bugs in device | |
1585 | drivers like double-freeing of DMA mappings or freeing mappings that | |
1586 | were never allocated. | |
1587 | This option causes a performance degredation. Use only if you want | |
1588 | to debug device drivers. If unsure, say N. | |
346e15be | 1589 | |
267c4025 | 1590 | source "samples/Kconfig" |
dc7d5527 JW |
1591 | |
1592 | source "lib/Kconfig.kgdb" | |
0a4af3b0 | 1593 |