Commit | Line | Data |
---|---|---|
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 | |
f346f4b3 AB |
315 | config DEBUG_KERNEL |
316 | bool "Kernel debugging" | |
fef2c9bc | 317 | help |
f346f4b3 AB |
318 | Say Y here if you are developing drivers or trying to debug and |
319 | identify kernel problems. | |
fef2c9bc | 320 | |
0610c8a8 | 321 | menu "Memory Debugging" |
fef2c9bc | 322 | |
0610c8a8 | 323 | source mm/Kconfig.debug |
fef2c9bc | 324 | |
0610c8a8 DH |
325 | config DEBUG_OBJECTS |
326 | bool "Debug object operations" | |
327 | depends on DEBUG_KERNEL | |
9c44bc03 | 328 | help |
0610c8a8 DH |
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. | |
9c44bc03 | 332 | |
0610c8a8 DH |
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. | |
9c44bc03 | 338 | |
0610c8a8 DH |
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. | |
3ac7fe5a | 347 | |
c6f3a97f TG |
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 | ||
dc186ad7 TG |
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 | ||
551d55a9 MD |
364 | config DEBUG_OBJECTS_RCU_HEAD |
365 | bool "Debug RCU callbacks objects" | |
fc2ecf7e | 366 | depends on DEBUG_OBJECTS |
551d55a9 MD |
367 | help |
368 | Enable this to turn on debugging of RCU list heads (call_rcu() usage). | |
369 | ||
e2852ae8 TH |
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 | ||
3ae70205 IM |
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 | ||
1da177e4 | 386 | config DEBUG_SLAB |
4a2f0acf | 387 | bool "Debug slab memory allocations" |
7d46d9e6 | 388 | depends on DEBUG_KERNEL && SLAB && !KMEMCHECK |
1da177e4 LT |
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 | ||
871751e2 AV |
394 | config DEBUG_SLAB_LEAK |
395 | bool "Memory leak debugging" | |
396 | depends on DEBUG_SLAB | |
397 | ||
f0630fff CL |
398 | config SLUB_DEBUG_ON |
399 | bool "SLUB debugging on by default" | |
7d46d9e6 | 400 | depends on SLUB && SLUB_DEBUG && !KMEMCHECK |
f0630fff CL |
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 | ||
8ff12cfc CL |
411 | config SLUB_STATS |
412 | default n | |
413 | bool "Enable SLUB performance statistics" | |
ab4d5ed5 | 414 | depends on SLUB && SYSFS |
8ff12cfc CL |
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 | ||
b69ec42b CM |
424 | config HAVE_DEBUG_KMEMLEAK |
425 | bool | |
426 | ||
3bba00d7 CM |
427 | config DEBUG_KMEMLEAK |
428 | bool "Kernel memory leak detector" | |
525c1f92 | 429 | depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK |
79e0d9bd | 430 | select DEBUG_FS |
3bba00d7 CM |
431 | select STACKTRACE if STACKTRACE_SUPPORT |
432 | select KALLSYMS | |
b60e26a2 | 433 | select CRC32 |
3bba00d7 CM |
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 | ||
0610c8a8 DH |
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 | ||
a304e1b8 DW |
598 | config DEBUG_SHIRQ |
599 | bool "Debug shared IRQ handlers" | |
600 | depends on DEBUG_KERNEL && GENERIC_HARDIRQS | |
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 | ||
92aef8fb DH |
607 | menu "Debug Lockups and Hangs" |
608 | ||
58687acb DZ |
609 | config LOCKUP_DETECTOR |
610 | bool "Detect Hard and Soft Lockups" | |
dea20a3f | 611 | depends on DEBUG_KERNEL && !S390 |
8446f1d3 | 612 | help |
58687acb DZ |
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 | |
5f329089 | 617 | mode for more than 20 seconds, without giving other tasks a |
58687acb DZ |
618 | chance to run. The current stack trace is displayed upon |
619 | detection and the system will stay locked up. | |
8446f1d3 | 620 | |
58687acb | 621 | Hardlockups are bugs that cause the CPU to loop in kernel mode |
5f329089 | 622 | for more than 10 seconds, without letting other interrupts have a |
58687acb DZ |
623 | chance to run. The current stack trace is displayed upon detection |
624 | and the system will stay locked up. | |
8446f1d3 | 625 | |
58687acb | 626 | The overhead should be minimal. A periodic hrtimer runs to |
5f329089 FLVC |
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. | |
8446f1d3 | 632 | |
23637d47 | 633 | config HARDLOCKUP_DETECTOR |
8f1f66ed JB |
634 | def_bool y |
635 | depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG | |
636 | depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI | |
8446f1d3 | 637 | |
fef2c9bc DZ |
638 | config BOOTPARAM_HARDLOCKUP_PANIC |
639 | bool "Panic (Reboot) On Hard Lockups" | |
8f1f66ed | 640 | depends on HARDLOCKUP_DETECTOR |
fef2c9bc DZ |
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 | |
5f329089 FLVC |
644 | mode with interrupts disabled for more than 10 seconds (configurable |
645 | using the watchdog_thresh sysctl). | |
fef2c9bc DZ |
646 | |
647 | Say N if unsure. | |
648 | ||
649 | config BOOTPARAM_HARDLOCKUP_PANIC_VALUE | |
650 | int | |
8f1f66ed | 651 | depends on HARDLOCKUP_DETECTOR |
fef2c9bc DZ |
652 | range 0 1 |
653 | default 0 if !BOOTPARAM_HARDLOCKUP_PANIC | |
654 | default 1 if BOOTPARAM_HARDLOCKUP_PANIC | |
655 | ||
9c44bc03 IM |
656 | config BOOTPARAM_SOFTLOCKUP_PANIC |
657 | bool "Panic (Reboot) On Soft Lockups" | |
89d7ce2a | 658 | depends on LOCKUP_DETECTOR |
9c44bc03 IM |
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 | |
5f329089 FLVC |
662 | mode for more than 20 seconds (configurable using the watchdog_thresh |
663 | sysctl), without giving other tasks a chance to run. | |
9c44bc03 IM |
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 | |
e16bb1d7 | 675 | depends on LOCKUP_DETECTOR |
9c44bc03 IM |
676 | range 0 1 |
677 | default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC | |
678 | default 1 if BOOTPARAM_SOFTLOCKUP_PANIC | |
679 | ||
e162b39a MSB |
680 | config DETECT_HUNG_TASK |
681 | bool "Detect Hung Tasks" | |
682 | depends on DEBUG_KERNEL | |
8edbb83e | 683 | default LOCKUP_DETECTOR |
e162b39a | 684 | help |
0610c8a8 DH |
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. | |
1da177e4 | 688 | |
0610c8a8 DH |
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. | |
871751e2 | 694 | |
0610c8a8 DH |
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 | |
f0630fff | 699 | help |
0610c8a8 DH |
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. | |
f0630fff | 703 | |
0610c8a8 DH |
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. | |
8ff12cfc | 707 | |
0610c8a8 DH |
708 | A timeout of 0 disables the check. The default is two minutes. |
709 | Keeping the default should be fine in most cases. | |
b69ec42b | 710 | |
0610c8a8 DH |
711 | config BOOTPARAM_HUNG_TASK_PANIC |
712 | bool "Panic (Reboot) On Hung Tasks" | |
713 | depends on DETECT_HUNG_TASK | |
3bba00d7 | 714 | help |
0610c8a8 DH |
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. | |
3bba00d7 | 718 | |
0610c8a8 DH |
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. | |
bf96d1e3 | 724 | |
0610c8a8 | 725 | Say N if unsure. |
bf96d1e3 | 726 | |
0610c8a8 DH |
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 | |
3bba00d7 | 733 | |
92aef8fb DH |
734 | endmenu # "Debug lockups and hangs" |
735 | ||
736 | config PANIC_ON_OOPS | |
737 | bool "Panic on Oops" | |
a9d9058a | 738 | help |
92aef8fb DH |
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. | |
a9d9058a | 742 | |
92aef8fb DH |
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 | ||
0610c8a8 DH |
755 | config SCHED_DEBUG |
756 | bool "Collect scheduler debugging info" | |
757 | depends on DEBUG_KERNEL && PROC_FS | |
758 | default y | |
0822ee4a | 759 | help |
0610c8a8 DH |
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. | |
0822ee4a | 763 | |
0610c8a8 DH |
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. | |
0822ee4a | 775 | |
0610c8a8 DH |
776 | config TIMER_STATS |
777 | bool "Collect kernel timers statistics" | |
778 | depends on DEBUG_KERNEL && PROC_FS | |
ab0155a2 | 779 | help |
0610c8a8 DH |
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). | |
ab0155a2 | 789 | |
1da177e4 LT |
790 | config DEBUG_PREEMPT |
791 | bool "Debug preemptible kernel" | |
01deab98 | 792 | depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT |
1da177e4 LT |
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 | ||
9eade16b DH |
800 | menu "Lock Debugging (spinlocks, mutexes, etc...)" |
801 | ||
e7eebaf6 IM |
802 | config DEBUG_RT_MUTEXES |
803 | bool "RT Mutex debugging, deadlock detection" | |
e7eebaf6 IM |
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 | ||
61a87122 TG |
814 | config RT_MUTEX_TESTER |
815 | bool "Built-in scriptable tester for rt-mutexes" | |
a1583d3e | 816 | depends on DEBUG_KERNEL && RT_MUTEXES |
61a87122 TG |
817 | help |
818 | This option enables a rt-mutex tester. | |
819 | ||
1da177e4 | 820 | config DEBUG_SPINLOCK |
4d9f34ad | 821 | bool "Spinlock and rw-lock debugging: basic checks" |
1da177e4 | 822 | depends on DEBUG_KERNEL |
e335e3eb | 823 | select UNINLINE_SPIN_UNLOCK |
1da177e4 LT |
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 | ||
4d9f34ad IM |
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 | ||
23010027 DV |
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 | ||
4d9f34ad IM |
850 | config DEBUG_LOCK_ALLOC |
851 | bool "Lock debugging: detect incorrect freeing of live locks" | |
517e7aa5 | 852 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
853 | select DEBUG_SPINLOCK |
854 | select DEBUG_MUTEXES | |
4d9f34ad IM |
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" | |
517e7aa5 | 866 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
867 | select LOCKDEP |
868 | select DEBUG_SPINLOCK | |
869 | select DEBUG_MUTEXES | |
4d9f34ad | 870 | select DEBUG_LOCK_ALLOC |
46b93b74 | 871 | select TRACE_IRQFLAGS |
4d9f34ad IM |
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 | |
517e7aa5 | 909 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad | 910 | select STACKTRACE |
79aac889 | 911 | select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE |
4d9f34ad IM |
912 | select KALLSYMS |
913 | select KALLSYMS_ALL | |
914 | ||
f20786ff | 915 | config LOCK_STAT |
fdfb870f | 916 | bool "Lock usage statistics" |
f20786ff PZ |
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 | ||
a560aa48 PZ |
926 | For more details, see Documentation/lockstat.txt |
927 | ||
dd8b1cf6 FW |
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. | |
84c6f88f HM |
932 | |
933 | CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. | |
dd8b1cf6 | 934 | (CONFIG_LOCKDEP defines "acquire" and "release" events.) |
84c6f88f | 935 | |
4d9f34ad IM |
936 | config DEBUG_LOCKDEP |
937 | bool "Lock dependency engine debugging" | |
517e7aa5 | 938 | depends on DEBUG_KERNEL && LOCKDEP |
4d9f34ad IM |
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 | ||
d902db1e FW |
944 | config DEBUG_ATOMIC_SLEEP |
945 | bool "Sleep inside atomic section checking" | |
e8f7c70f | 946 | select PREEMPT_COUNT |
1da177e4 LT |
947 | depends on DEBUG_KERNEL |
948 | help | |
949 | If you say Y here, various routines which may sleep will become very | |
d902db1e FW |
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... | |
1da177e4 | 953 | |
cae2ed9a IM |
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 | ||
9eade16b | 965 | endmenu # lock debugging |
8637c099 | 966 | |
9eade16b DH |
967 | config TRACE_IRQFLAGS |
968 | bool | |
5ca43f6c | 969 | help |
9eade16b DH |
970 | Enables hooks to interrupt enabling and disabling for |
971 | either tracing or lock debugging. | |
5ca43f6c | 972 | |
8637c099 IM |
973 | config STACKTRACE |
974 | bool | |
975 | depends on STACKTRACE_SUPPORT | |
5ca43f6c | 976 | |
1da177e4 LT |
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 | ||
9b2a60c4 CM |
984 | config HAVE_DEBUG_BUGVERBOSE |
985 | bool | |
986 | ||
1da177e4 | 987 | config DEBUG_BUGVERBOSE |
6a108a14 | 988 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT |
9b2a60c4 | 989 | depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE) |
8420e7ef | 990 | default y |
1da177e4 LT |
991 | help |
992 | Say Y here to make BUG() panics output the file name and line number | |
993 | of the BUG call as well as the EIP and oops trace. This aids | |
994 | debugging but costs about 70-100K of memory. | |
995 | ||
ad775f5a DH |
996 | config DEBUG_WRITECOUNT |
997 | bool "Debug filesystem writers count" | |
998 | depends on DEBUG_KERNEL | |
999 | help | |
1000 | Enable this to catch wrong use of the writers count in struct | |
1001 | vfsmount. This will increase the size of each file struct by | |
1002 | 32 bits. | |
1003 | ||
1004 | If unsure, say N. | |
1005 | ||
199a9afc DJ |
1006 | config DEBUG_LIST |
1007 | bool "Debug linked list manipulation" | |
1008 | depends on DEBUG_KERNEL | |
1009 | help | |
1010 | Enable this to turn on extended checks in the linked-list | |
1011 | walking routines. | |
1012 | ||
1013 | If unsure, say N. | |
1014 | ||
d6ec0842 JA |
1015 | config DEBUG_SG |
1016 | bool "Debug SG table operations" | |
1017 | depends on DEBUG_KERNEL | |
1018 | help | |
1019 | Enable this to turn on checks on scatter-gather tables. This can | |
1020 | help find problems with drivers that do not properly initialize | |
1021 | their sg tables. | |
1022 | ||
1023 | If unsure, say N. | |
1024 | ||
1b2439db AV |
1025 | config DEBUG_NOTIFIERS |
1026 | bool "Debug notifier call chains" | |
1027 | depends on DEBUG_KERNEL | |
1028 | help | |
1029 | Enable this to turn on sanity checking for notifier call chains. | |
1030 | This is most useful for kernel developers to make sure that | |
1031 | modules properly unregister themselves from notifier chains. | |
1032 | This is a relatively cheap check but if you care about maximum | |
1033 | performance, say N. | |
1034 | ||
e0e81739 DH |
1035 | config DEBUG_CREDENTIALS |
1036 | bool "Debug credential management" | |
1037 | depends on DEBUG_KERNEL | |
1038 | help | |
1039 | Enable this to turn on some debug checking for credential | |
1040 | management. The additional code keeps track of the number of | |
1041 | pointers from task_structs to any given cred struct, and checks to | |
1042 | see that this number never exceeds the usage count of the cred | |
1043 | struct. | |
1044 | ||
1045 | Furthermore, if SELinux is enabled, this also checks that the | |
1046 | security pointer in the cred struct is never seen to be invalid. | |
1047 | ||
1048 | If unsure, say N. | |
1049 | ||
2f03e3ca DH |
1050 | menu "RCU Debugging" |
1051 | ||
1052 | config PROVE_RCU | |
1053 | bool "RCU debugging: prove RCU correctness" | |
1054 | depends on PROVE_LOCKING | |
1055 | default n | |
1056 | help | |
1057 | This feature enables lockdep extensions that check for correct | |
1058 | use of RCU APIs. This is currently under development. Say Y | |
1059 | if you want to debug RCU usage or help work on the PROVE_RCU | |
1060 | feature. | |
1061 | ||
1062 | Say N if you are unsure. | |
1063 | ||
1064 | config PROVE_RCU_REPEATEDLY | |
1065 | bool "RCU debugging: don't disable PROVE_RCU on first splat" | |
1066 | depends on PROVE_RCU | |
1067 | default n | |
1068 | help | |
1069 | By itself, PROVE_RCU will disable checking upon issuing the | |
1070 | first warning (or "splat"). This feature prevents such | |
1071 | disabling, allowing multiple RCU-lockdep warnings to be printed | |
1072 | on a single reboot. | |
1073 | ||
1074 | Say Y to allow multiple RCU-lockdep warnings per boot. | |
1075 | ||
1076 | Say N if you are unsure. | |
1077 | ||
1078 | config PROVE_RCU_DELAY | |
1079 | bool "RCU debugging: preemptible RCU race provocation" | |
1080 | depends on DEBUG_KERNEL && PREEMPT_RCU | |
1081 | default n | |
1082 | help | |
1083 | There is a class of races that involve an unlikely preemption | |
1084 | of __rcu_read_unlock() just after ->rcu_read_lock_nesting has | |
1085 | been set to INT_MIN. This feature inserts a delay at that | |
1086 | point to increase the probability of these races. | |
1087 | ||
1088 | Say Y to increase probability of preemption of __rcu_read_unlock(). | |
1089 | ||
1090 | Say N if you are unsure. | |
1091 | ||
1092 | config SPARSE_RCU_POINTER | |
1093 | bool "RCU debugging: sparse-based checks for pointer usage" | |
1094 | default n | |
1095 | help | |
1096 | This feature enables the __rcu sparse annotation for | |
1097 | RCU-protected pointers. This annotation will cause sparse | |
1098 | to flag any non-RCU used of annotated pointers. This can be | |
1099 | helpful when debugging RCU usage. Please note that this feature | |
1100 | is not intended to enforce code cleanliness; it is instead merely | |
1101 | a debugging aid. | |
1102 | ||
1103 | Say Y to make sparse flag questionable use of RCU-protected pointers | |
1104 | ||
1105 | Say N if you are unsure. | |
1106 | ||
a241ec65 PM |
1107 | config RCU_TORTURE_TEST |
1108 | tristate "torture tests for RCU" | |
1109 | depends on DEBUG_KERNEL | |
1110 | default n | |
1111 | help | |
1112 | This option provides a kernel module that runs torture tests | |
1113 | on the RCU infrastructure. The kernel module may be built | |
1114 | after the fact on the running kernel to be tested, if desired. | |
1115 | ||
31a72bce PM |
1116 | Say Y here if you want RCU torture tests to be built into |
1117 | the kernel. | |
a241ec65 PM |
1118 | Say M if you want the RCU torture tests to build as a module. |
1119 | Say N if you are unsure. | |
8bb31b9d | 1120 | |
31a72bce PM |
1121 | config RCU_TORTURE_TEST_RUNNABLE |
1122 | bool "torture tests for RCU runnable by default" | |
1123 | depends on RCU_TORTURE_TEST = y | |
1124 | default n | |
1125 | help | |
1126 | This option provides a way to build the RCU torture tests | |
1127 | directly into the kernel without them starting up at boot | |
1128 | time. You can use /proc/sys/kernel/rcutorture_runnable | |
1129 | to manually override this setting. This /proc file is | |
1130 | available only when the RCU torture tests have been built | |
1131 | into the kernel. | |
1132 | ||
1133 | Say Y here if you want the RCU torture tests to start during | |
1134 | boot (you probably don't). | |
1135 | Say N here if you want the RCU torture tests to start only | |
1136 | after being manually enabled via /proc. | |
1137 | ||
b163760e PM |
1138 | config RCU_CPU_STALL_TIMEOUT |
1139 | int "RCU CPU stall timeout in seconds" | |
6bfc09e2 | 1140 | depends on RCU_STALL_COMMON |
b163760e | 1141 | range 3 300 |
c896054f | 1142 | default 21 |
b163760e PM |
1143 | help |
1144 | If a given RCU grace period extends more than the specified | |
1145 | number of seconds, a CPU stall warning is printed. If the | |
1146 | RCU grace period persists, additional CPU stall warnings are | |
1147 | printed at more widely spaced intervals. | |
1148 | ||
1ed509a2 PM |
1149 | config RCU_CPU_STALL_VERBOSE |
1150 | bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR" | |
a00e0d71 | 1151 | depends on TREE_PREEMPT_RCU |
55ec936f | 1152 | default y |
1ed509a2 PM |
1153 | help |
1154 | This option causes RCU to printk detailed per-task information | |
1155 | for any tasks that are stalling the current RCU grace period. | |
67182ae1 PM |
1156 | |
1157 | Say N if you are unsure. | |
1158 | ||
1ed509a2 PM |
1159 | Say Y if you want to enable such checks. |
1160 | ||
a858af28 PM |
1161 | config RCU_CPU_STALL_INFO |
1162 | bool "Print additional diagnostics on RCU CPU stall" | |
1163 | depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL | |
1164 | default n | |
1165 | help | |
1166 | For each stalled CPU that is aware of the current RCU grace | |
1167 | period, print out additional per-CPU diagnostic information | |
1168 | regarding scheduling-clock ticks, idle state, and, | |
1169 | for RCU_FAST_NO_HZ kernels, idle-entry state. | |
1170 | ||
1171 | Say N if you are unsure. | |
1172 | ||
1173 | Say Y if you want to enable such diagnostics. | |
1174 | ||
5c8806a0 PM |
1175 | config RCU_TRACE |
1176 | bool "Enable tracing for RCU" | |
6dab2778 | 1177 | depends on DEBUG_KERNEL |
52494535 | 1178 | select TRACE_CLOCK |
6dab2778 | 1179 | help |
5c8806a0 PM |
1180 | This option provides tracing in RCU which presents stats |
1181 | in debugfs for debugging RCU implementation. | |
ad118c54 | 1182 | |
5c8806a0 | 1183 | Say Y here if you want to enable RCU tracing |
6dab2778 AV |
1184 | Say N if you are unsure. |
1185 | ||
2f03e3ca DH |
1186 | endmenu # "RCU Debugging" |
1187 | ||
870d6656 TH |
1188 | config DEBUG_BLOCK_EXT_DEVT |
1189 | bool "Force extended block device numbers and spread them" | |
1190 | depends on DEBUG_KERNEL | |
1191 | depends on BLOCK | |
759f8ca3 | 1192 | default n |
870d6656 | 1193 | help |
0e11e342 TH |
1194 | BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON |
1195 | SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT | |
1196 | YOU ARE DOING. Distros, please enable this and fix whatever | |
1197 | is broken. | |
1198 | ||
870d6656 TH |
1199 | Conventionally, block device numbers are allocated from |
1200 | predetermined contiguous area. However, extended block area | |
1201 | may introduce non-contiguous block device numbers. This | |
1202 | option forces most block device numbers to be allocated from | |
1203 | the extended space and spreads them to discover kernel or | |
1204 | userland code paths which assume predetermined contiguous | |
1205 | device number allocation. | |
1206 | ||
55dc7db7 TH |
1207 | Note that turning on this debug option shuffles all the |
1208 | device numbers for all IDE and SCSI devices including libata | |
1209 | ones, so root partition specified using device number | |
1210 | directly (via rdev or root=MAJ:MIN) won't work anymore. | |
1211 | Textual device names (root=/dev/sdXn) will continue to work. | |
1212 | ||
870d6656 TH |
1213 | Say N if you are unsure. |
1214 | ||
8d438288 AM |
1215 | config NOTIFIER_ERROR_INJECTION |
1216 | tristate "Notifier error injection" | |
1217 | depends on DEBUG_KERNEL | |
1218 | select DEBUG_FS | |
1219 | help | |
e41e85cc | 1220 | This option provides the ability to inject artificial errors to |
8d438288 AM |
1221 | specified notifier chain callbacks. It is useful to test the error |
1222 | handling of notifier call chain failures. | |
1223 | ||
1224 | Say N if unsure. | |
1225 | ||
c9d221f8 AM |
1226 | config CPU_NOTIFIER_ERROR_INJECT |
1227 | tristate "CPU notifier error injection module" | |
f5a9f52e | 1228 | depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION |
c9d221f8 AM |
1229 | help |
1230 | This option provides a kernel module that can be used to test | |
e41e85cc | 1231 | the error handling of the cpu notifiers by injecting artificial |
f5a9f52e AM |
1232 | errors to CPU notifier chain callbacks. It is controlled through |
1233 | debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu | |
1234 | ||
1235 | If the notifier call chain should be failed with some events | |
1236 | notified, write the error code to "actions/<notifier event>/error". | |
1237 | ||
1238 | Example: Inject CPU offline error (-1 == -EPERM) | |
1239 | ||
1240 | # cd /sys/kernel/debug/notifier-error-inject/cpu | |
1241 | # echo -1 > actions/CPU_DOWN_PREPARE/error | |
1242 | # echo 0 > /sys/devices/system/cpu/cpu1/online | |
1243 | bash: echo: write error: Operation not permitted | |
c9d221f8 AM |
1244 | |
1245 | To compile this code as a module, choose M here: the module will | |
1246 | be called cpu-notifier-error-inject. | |
1247 | ||
1248 | If unsure, say N. | |
1249 | ||
048b9c35 AM |
1250 | config PM_NOTIFIER_ERROR_INJECT |
1251 | tristate "PM notifier error injection module" | |
1252 | depends on PM && NOTIFIER_ERROR_INJECTION | |
1253 | default m if PM_DEBUG | |
1254 | help | |
e41e85cc | 1255 | This option provides the ability to inject artificial errors to |
048b9c35 AM |
1256 | PM notifier chain callbacks. It is controlled through debugfs |
1257 | interface /sys/kernel/debug/notifier-error-inject/pm | |
1258 | ||
1259 | If the notifier call chain should be failed with some events | |
1260 | notified, write the error code to "actions/<notifier event>/error". | |
1261 | ||
1262 | Example: Inject PM suspend error (-12 = -ENOMEM) | |
1263 | ||
1264 | # cd /sys/kernel/debug/notifier-error-inject/pm/ | |
1265 | # echo -12 > actions/PM_SUSPEND_PREPARE/error | |
1266 | # echo mem > /sys/power/state | |
1267 | bash: echo: write error: Cannot allocate memory | |
1268 | ||
1269 | To compile this code as a module, choose M here: the module will | |
1270 | be called pm-notifier-error-inject. | |
1271 | ||
1272 | If unsure, say N. | |
1273 | ||
d526e85f BH |
1274 | config OF_RECONFIG_NOTIFIER_ERROR_INJECT |
1275 | tristate "OF reconfig notifier error injection module" | |
1276 | depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION | |
08dfb4dd | 1277 | help |
e41e85cc | 1278 | This option provides the ability to inject artificial errors to |
d526e85f | 1279 | OF reconfig notifier chain callbacks. It is controlled |
08dfb4dd | 1280 | through debugfs interface under |
d526e85f | 1281 | /sys/kernel/debug/notifier-error-inject/OF-reconfig/ |
08dfb4dd AM |
1282 | |
1283 | If the notifier call chain should be failed with some events | |
1284 | notified, write the error code to "actions/<notifier event>/error". | |
1285 | ||
1286 | To compile this code as a module, choose M here: the module will | |
e12a95f4 | 1287 | be called of-reconfig-notifier-error-inject. |
08dfb4dd AM |
1288 | |
1289 | If unsure, say N. | |
1290 | ||
6ff1cb35 | 1291 | config FAULT_INJECTION |
1ab8509a AM |
1292 | bool "Fault-injection framework" |
1293 | depends on DEBUG_KERNEL | |
329409ae AM |
1294 | help |
1295 | Provide fault-injection framework. | |
1296 | For more details, see Documentation/fault-injection/. | |
6ff1cb35 | 1297 | |
8a8b6502 | 1298 | config FAILSLAB |
1ab8509a AM |
1299 | bool "Fault-injection capability for kmalloc" |
1300 | depends on FAULT_INJECTION | |
773ff60e | 1301 | depends on SLAB || SLUB |
8a8b6502 | 1302 | help |
1ab8509a | 1303 | Provide fault-injection capability for kmalloc. |
8a8b6502 | 1304 | |
933e312e AM |
1305 | config FAIL_PAGE_ALLOC |
1306 | bool "Fault-injection capabilitiy for alloc_pages()" | |
1ab8509a | 1307 | depends on FAULT_INJECTION |
933e312e | 1308 | help |
1ab8509a | 1309 | Provide fault-injection capability for alloc_pages(). |
933e312e | 1310 | |
c17bb495 | 1311 | config FAIL_MAKE_REQUEST |
86327d19 | 1312 | bool "Fault-injection capability for disk IO" |
581d4e28 | 1313 | depends on FAULT_INJECTION && BLOCK |
c17bb495 | 1314 | help |
1ab8509a | 1315 | Provide fault-injection capability for disk IO. |
c17bb495 | 1316 | |
581d4e28 | 1317 | config FAIL_IO_TIMEOUT |
f4d01439 | 1318 | bool "Fault-injection capability for faking disk interrupts" |
581d4e28 JA |
1319 | depends on FAULT_INJECTION && BLOCK |
1320 | help | |
1321 | Provide fault-injection capability on end IO handling. This | |
1322 | will make the block layer "forget" an interrupt as configured, | |
1323 | thus exercising the error handling. | |
1324 | ||
1325 | Only works with drivers that use the generic timeout handling, | |
1326 | for others it wont do anything. | |
1327 | ||
1b676f70 PF |
1328 | config FAIL_MMC_REQUEST |
1329 | bool "Fault-injection capability for MMC IO" | |
1330 | select DEBUG_FS | |
1331 | depends on FAULT_INJECTION && MMC | |
1332 | help | |
1333 | Provide fault-injection capability for MMC IO. | |
1334 | This will make the mmc core return data errors. This is | |
1335 | useful to test the error handling in the mmc block device | |
1336 | and to test how the mmc host driver handles retries from | |
1337 | the block device. | |
1338 | ||
6ff1cb35 AM |
1339 | config FAULT_INJECTION_DEBUG_FS |
1340 | bool "Debugfs entries for fault-injection capabilities" | |
1ab8509a | 1341 | depends on FAULT_INJECTION && SYSFS && DEBUG_FS |
6ff1cb35 | 1342 | help |
1ab8509a | 1343 | Enable configuration of fault-injection capabilities via debugfs. |
1df49008 AM |
1344 | |
1345 | config FAULT_INJECTION_STACKTRACE_FILTER | |
1346 | bool "stacktrace filter for fault-injection capabilities" | |
1347 | depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT | |
6d690dca | 1348 | depends on !X86_64 |
1df49008 | 1349 | select STACKTRACE |
25c87eae | 1350 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND |
1df49008 AM |
1351 | help |
1352 | Provide stacktrace filter for fault-injection capabilities | |
267c4025 | 1353 | |
9745512c AV |
1354 | config LATENCYTOP |
1355 | bool "Latency measuring infrastructure" | |
625fdcaa RD |
1356 | depends on HAVE_LATENCYTOP_SUPPORT |
1357 | depends on DEBUG_KERNEL | |
1358 | depends on STACKTRACE_SUPPORT | |
1359 | depends on PROC_FS | |
89bace65 | 1360 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND |
9745512c AV |
1361 | select KALLSYMS |
1362 | select KALLSYMS_ALL | |
1363 | select STACKTRACE | |
1364 | select SCHEDSTATS | |
1365 | select SCHED_DEBUG | |
9745512c AV |
1366 | help |
1367 | Enable this option if you want to use the LatencyTOP tool | |
1368 | to find out which userspace is blocking on what kernel operations. | |
1369 | ||
446f24d1 SB |
1370 | config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS |
1371 | bool | |
1372 | ||
1373 | config DEBUG_STRICT_USER_COPY_CHECKS | |
1374 | bool "Strict user copy size checks" | |
1375 | depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS | |
1376 | depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING | |
1377 | help | |
1378 | Enabling this option turns a certain set of sanity checks for user | |
1379 | copy operations into compile time failures. | |
1380 | ||
1381 | The copy_from_user() etc checks are there to help test if there | |
1382 | are sufficient security checks on the length argument of | |
1383 | the copy operation, by having gcc prove that the argument is | |
1384 | within bounds. | |
1385 | ||
1386 | If unsure, say N. | |
1387 | ||
16444a8a ACM |
1388 | source kernel/trace/Kconfig |
1389 | ||
881c5149 DH |
1390 | menu "Runtime Testing" |
1391 | ||
1392 | config LKDTM | |
1393 | tristate "Linux Kernel Dump Test Tool Module" | |
1394 | depends on DEBUG_FS | |
1395 | depends on BLOCK | |
1396 | default n | |
1397 | help | |
1398 | This module enables testing of the different dumping mechanisms by | |
1399 | inducing system failures at predefined crash points. | |
1400 | If you don't need it: say N | |
1401 | Choose M here to compile this code as a module. The module will be | |
1402 | called lkdtm. | |
1403 | ||
1404 | Documentation on how to use the module can be found in | |
1405 | Documentation/fault-injection/provoke-crashes.txt | |
1406 | ||
1407 | config TEST_LIST_SORT | |
1408 | bool "Linked list sorting test" | |
1409 | depends on DEBUG_KERNEL | |
1410 | help | |
1411 | Enable this to turn on 'list_sort()' function test. This test is | |
1412 | executed only once during system boot, so affects only boot time. | |
1413 | ||
1414 | If unsure, say N. | |
1415 | ||
1416 | config KPROBES_SANITY_TEST | |
1417 | bool "Kprobes sanity tests" | |
1418 | depends on DEBUG_KERNEL | |
1419 | depends on KPROBES | |
1420 | default n | |
1421 | help | |
1422 | This option provides for testing basic kprobes functionality on | |
1423 | boot. A sample kprobe, jprobe and kretprobe are inserted and | |
1424 | verified for functionality. | |
1425 | ||
1426 | Say N if you are unsure. | |
1427 | ||
1428 | config BACKTRACE_SELF_TEST | |
1429 | tristate "Self test for the backtrace code" | |
1430 | depends on DEBUG_KERNEL | |
1431 | default n | |
1432 | help | |
1433 | This option provides a kernel module that can be used to test | |
1434 | the kernel stack backtrace code. This option is not useful | |
1435 | for distributions or general kernels, but only for kernel | |
1436 | developers working on architecture code. | |
1437 | ||
1438 | Note that if you want to also test saved backtraces, you will | |
1439 | have to enable STACKTRACE as well. | |
1440 | ||
1441 | Say N if you are unsure. | |
1442 | ||
910a742d ML |
1443 | config RBTREE_TEST |
1444 | tristate "Red-Black tree test" | |
1445 | depends on m && DEBUG_KERNEL | |
1446 | help | |
1447 | A benchmark measuring the performance of the rbtree library. | |
1448 | Also includes rbtree invariant checks. | |
1449 | ||
fff3fd8a ML |
1450 | config INTERVAL_TREE_TEST |
1451 | tristate "Interval tree test" | |
1452 | depends on m && DEBUG_KERNEL | |
1453 | help | |
1454 | A benchmark measuring the performance of the interval tree library | |
1455 | ||
881c5149 DH |
1456 | config ATOMIC64_SELFTEST |
1457 | bool "Perform an atomic64_t self-test at boot" | |
1458 | help | |
1459 | Enable this option to test the atomic64_t functions at boot. | |
1460 | ||
1461 | If unsure, say N. | |
1462 | ||
1463 | config ASYNC_RAID6_TEST | |
1464 | tristate "Self test for hardware accelerated raid6 recovery" | |
1465 | depends on ASYNC_RAID6_RECOV | |
1466 | select ASYNC_MEMCPY | |
1467 | ---help--- | |
1468 | This is a one-shot self test that permutes through the | |
1469 | recovery of all the possible two disk failure scenarios for a | |
1470 | N-disk array. Recovery is performed with the asynchronous | |
1471 | raid6 recovery routines, and will optionally use an offload | |
1472 | engine if one is available. | |
1473 | ||
1474 | If unsure, say N. | |
1475 | ||
1476 | config TEST_STRING_HELPERS | |
1477 | tristate "Test functions located in the string_helpers module at runtime" | |
1478 | ||
1479 | config TEST_KSTRTOX | |
1480 | tristate "Test kstrto*() family of functions at runtime" | |
1481 | ||
1482 | endmenu # runtime tests | |
1483 | ||
f212ec4b | 1484 | config PROVIDE_OHCI1394_DMA_INIT |
080de8c2 | 1485 | bool "Remote debugging over FireWire early on boot" |
f212ec4b BK |
1486 | depends on PCI && X86 |
1487 | help | |
1488 | If you want to debug problems which hang or crash the kernel early | |
1489 | on boot and the crashing machine has a FireWire port, you can use | |
1490 | this feature to remotely access the memory of the crashed machine | |
1491 | over FireWire. This employs remote DMA as part of the OHCI1394 | |
1492 | specification which is now the standard for FireWire controllers. | |
1493 | ||
1494 | With remote DMA, you can monitor the printk buffer remotely using | |
1495 | firescope and access all memory below 4GB using fireproxy from gdb. | |
1496 | Even controlling a kernel debugger is possible using remote DMA. | |
1497 | ||
1498 | Usage: | |
1499 | ||
1500 | If ohci1394_dma=early is used as boot parameter, it will initialize | |
1501 | all OHCI1394 controllers which are found in the PCI config space. | |
1502 | ||
1503 | As all changes to the FireWire bus such as enabling and disabling | |
1504 | devices cause a bus reset and thereby disable remote DMA for all | |
1505 | devices, be sure to have the cable plugged and FireWire enabled on | |
1506 | the debugging host before booting the debug target for debugging. | |
1507 | ||
1508 | This code (~1k) is freed after boot. By then, the firewire stack | |
1509 | in charge of the OHCI-1394 controllers should be used instead. | |
1510 | ||
1511 | See Documentation/debugging-via-ohci1394.txt for more information. | |
9745512c | 1512 | |
080de8c2 SR |
1513 | config FIREWIRE_OHCI_REMOTE_DMA |
1514 | bool "Remote debugging over FireWire with firewire-ohci" | |
1515 | depends on FIREWIRE_OHCI | |
1516 | help | |
1517 | This option lets you use the FireWire bus for remote debugging | |
1518 | with help of the firewire-ohci driver. It enables unfiltered | |
1519 | remote DMA in firewire-ohci. | |
1520 | See Documentation/debugging-via-ohci1394.txt for more information. | |
1521 | ||
1522 | If unsure, say N. | |
1523 | ||
152de30b | 1524 | config BUILD_DOCSRC |
3794f3e8 RD |
1525 | bool "Build targets in Documentation/ tree" |
1526 | depends on HEADERS_CHECK | |
1527 | help | |
1528 | This option attempts to build objects from the source files in the | |
1529 | kernel Documentation/ tree. | |
1530 | ||
1531 | Say N if you are unsure. | |
1532 | ||
5ee00bd4 JR |
1533 | config DMA_API_DEBUG |
1534 | bool "Enable debugging of DMA-API usage" | |
1535 | depends on HAVE_DMA_API_DEBUG | |
1536 | help | |
1537 | Enable this option to debug the use of the DMA API by device drivers. | |
1538 | With this option you will be able to detect common bugs in device | |
1539 | drivers like double-freeing of DMA mappings or freeing mappings that | |
1540 | were never allocated. | |
1541 | This option causes a performance degredation. Use only if you want | |
1542 | to debug device drivers. If unsure, say N. | |
346e15be | 1543 | |
267c4025 | 1544 | source "samples/Kconfig" |
dc7d5527 JW |
1545 | |
1546 | source "lib/Kconfig.kgdb" | |
0a4af3b0 | 1547 |