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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 | |
42a9dc0b | 18 | config MESSAGE_LOGLEVEL_DEFAULT |
5af5bcb8 MSB |
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" | |
12b13835 | 122 | depends on DEBUG_KERNEL && !COMPILE_TEST |
6dfc0665 DH |
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 | ||
866ced95 AK |
146 | config DEBUG_INFO_SPLIT |
147 | bool "Produce split debuginfo in .dwo files" | |
148 | depends on DEBUG_INFO | |
149 | help | |
150 | Generate debug info into separate .dwo files. This significantly | |
151 | reduces the build directory size for builds with DEBUG_INFO, | |
152 | because it stores the information only once on disk in .dwo | |
153 | files instead of multiple times in object files and executables. | |
154 | In addition the debug information is also compressed. | |
155 | ||
156 | Requires recent gcc (4.7+) and recent gdb/binutils. | |
157 | Any tool that packages or reads debug information would need | |
158 | to know about the .dwo files and include them. | |
159 | Incompatible with older versions of ccache. | |
160 | ||
bfaf2dd3 AK |
161 | config DEBUG_INFO_DWARF4 |
162 | bool "Generate dwarf4 debuginfo" | |
163 | depends on DEBUG_INFO | |
164 | help | |
165 | Generate dwarf4 debug info. This requires recent versions | |
166 | of gcc and gdb. It makes the debug information larger. | |
167 | But it significantly improves the success of resolving | |
168 | variables in gdb on optimized code. | |
169 | ||
de488443 JG |
170 | config ENABLE_WARN_DEPRECATED |
171 | bool "Enable __deprecated logic" | |
172 | default y | |
173 | help | |
174 | Enable the __deprecated logic in the kernel build. | |
175 | Disable this to suppress the "warning: 'foo' is deprecated | |
176 | (declared at kernel/power/somefile.c:1234)" messages. | |
177 | ||
cebc04ba AM |
178 | config ENABLE_MUST_CHECK |
179 | bool "Enable __must_check logic" | |
180 | default y | |
181 | help | |
182 | Enable the __must_check logic in the kernel build. Disable this to | |
183 | suppress the "warning: ignoring return value of 'foo', declared with | |
184 | attribute warn_unused_result" messages. | |
1da177e4 | 185 | |
35bb5b1e AK |
186 | config FRAME_WARN |
187 | int "Warn for stack frames larger than (needs gcc 4.4)" | |
188 | range 0 8192 | |
189 | default 1024 if !64BIT | |
190 | default 2048 if 64BIT | |
191 | help | |
192 | Tell gcc to warn at build time for stack frames larger than this. | |
193 | Setting this too low will cause a lot of warnings. | |
194 | Setting it to 0 disables the warning. | |
195 | Requires gcc 4.4 | |
196 | ||
99657c78 RD |
197 | config STRIP_ASM_SYMS |
198 | bool "Strip assembler-generated symbols during link" | |
199 | default n | |
200 | help | |
201 | Strip internal assembler-generated symbols during a link (symbols | |
202 | that look like '.Lxxx') so they don't pollute the output of | |
203 | get_wchan() and suchlike. | |
204 | ||
1873e870 AK |
205 | config READABLE_ASM |
206 | bool "Generate readable assembler code" | |
207 | depends on DEBUG_KERNEL | |
208 | help | |
209 | Disable some compiler optimizations that tend to generate human unreadable | |
210 | assembler output. This may make the kernel slightly slower, but it helps | |
211 | to keep kernel developers who have to stare a lot at assembler listings | |
212 | sane. | |
213 | ||
f71d20e9 AV |
214 | config UNUSED_SYMBOLS |
215 | bool "Enable unused/obsolete exported symbols" | |
216 | default y if X86 | |
217 | help | |
218 | Unused but exported symbols make the kernel needlessly bigger. For | |
219 | that reason most of these unused exports will soon be removed. This | |
220 | option is provided temporarily to provide a transition period in case | |
221 | some external kernel module needs one of these symbols anyway. If you | |
222 | encounter such a case in your module, consider if you are actually | |
223 | using the right API. (rationale: since nobody in the kernel is using | |
224 | this in a module, there is a pretty good chance it's actually the | |
225 | wrong interface to use). If you really need the symbol, please send a | |
226 | mail to the linux kernel mailing list mentioning the symbol and why | |
227 | you really need it, and what the merge plan to the mainline kernel for | |
228 | your module is. | |
229 | ||
48c96a36 JK |
230 | config PAGE_OWNER |
231 | bool "Track page owner" | |
232 | depends on DEBUG_KERNEL && STACKTRACE_SUPPORT | |
233 | select DEBUG_FS | |
234 | select STACKTRACE | |
235 | select PAGE_EXTENSION | |
236 | help | |
237 | This keeps track of what call chain is the owner of a page, may | |
238 | help to find bare alloc_page(s) leaks. Even if you include this | |
239 | feature on your build, it is disabled in default. You should pass | |
240 | "page_owner=on" to boot parameter in order to enable it. Eats | |
241 | a fair amount of memory if enabled. See tools/vm/page_owner_sort.c | |
242 | for user-space helper. | |
243 | ||
244 | If unsure, say N. | |
245 | ||
bf4735a4 DM |
246 | config DEBUG_FS |
247 | bool "Debug Filesystem" | |
bf4735a4 DM |
248 | help |
249 | debugfs is a virtual file system that kernel developers use to put | |
250 | debugging files into. Enable this option to be able to read and | |
251 | write to these files. | |
252 | ||
ff543332 RD |
253 | For detailed documentation on the debugfs API, see |
254 | Documentation/DocBook/filesystems. | |
255 | ||
bf4735a4 DM |
256 | If unsure, say N. |
257 | ||
258 | config HEADERS_CHECK | |
259 | bool "Run 'make headers_check' when building vmlinux" | |
260 | depends on !UML | |
261 | help | |
262 | This option will extract the user-visible kernel headers whenever | |
263 | building the kernel, and will run basic sanity checks on them to | |
264 | ensure that exported files do not attempt to include files which | |
265 | were not exported, etc. | |
266 | ||
267 | If you're making modifications to header files which are | |
268 | relevant for userspace, say 'Y', and check the headers | |
269 | exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in | |
270 | your build tree), to make sure they're suitable. | |
271 | ||
91341d4b SR |
272 | config DEBUG_SECTION_MISMATCH |
273 | bool "Enable full Section mismatch analysis" | |
91341d4b SR |
274 | help |
275 | The section mismatch analysis checks if there are illegal | |
276 | references from one section to another section. | |
e809ab01 MW |
277 | During linktime or runtime, some sections are dropped; |
278 | any use of code/data previously in these sections would | |
91341d4b | 279 | most likely result in an oops. |
e809ab01 | 280 | In the code, functions and variables are annotated with |
0db0628d | 281 | __init,, etc. (see the full list in include/linux/init.h), |
d6fbfa4f | 282 | which results in the code/data being placed in specific sections. |
e809ab01 MW |
283 | The section mismatch analysis is always performed after a full |
284 | kernel build, and enabling this option causes the following | |
285 | additional steps to occur: | |
286 | - Add the option -fno-inline-functions-called-once to gcc commands. | |
287 | When inlining a function annotated with __init in a non-init | |
288 | function, we would lose the section information and thus | |
91341d4b | 289 | the analysis would not catch the illegal reference. |
e809ab01 MW |
290 | This option tells gcc to inline less (but it does result in |
291 | a larger kernel). | |
292 | - Run the section mismatch analysis for each module/built-in.o file. | |
293 | When we run the section mismatch analysis on vmlinux.o, we | |
d6fbfa4f | 294 | lose valueble information about where the mismatch was |
91341d4b SR |
295 | introduced. |
296 | Running the analysis for each module/built-in.o file | |
e809ab01 MW |
297 | tells where the mismatch happens much closer to the |
298 | source. The drawback is that the same mismatch is | |
299 | reported at least twice. | |
300 | - Enable verbose reporting from modpost in order to help resolve | |
301 | the section mismatches that are reported. | |
91341d4b | 302 | |
6dfc0665 DH |
303 | # |
304 | # Select this config option from the architecture Kconfig, if it | |
305 | # is preferred to always offer frame pointers as a config | |
306 | # option on the architecture (regardless of KERNEL_DEBUG): | |
307 | # | |
308 | config ARCH_WANT_FRAME_POINTERS | |
309 | bool | |
f346f4b3 | 310 | help |
f346f4b3 | 311 | |
6dfc0665 DH |
312 | config FRAME_POINTER |
313 | bool "Compile the kernel with frame pointers" | |
314 | depends on DEBUG_KERNEL && \ | |
315 | (CRIS || M68K || FRV || UML || \ | |
316 | AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \ | |
317 | ARCH_WANT_FRAME_POINTERS | |
318 | default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS | |
a304e1b8 | 319 | help |
6dfc0665 DH |
320 | If you say Y here the resulting kernel image will be slightly |
321 | larger and slower, but it gives very useful debugging information | |
322 | in case of kernel bugs. (precise oopses/stacktraces/warnings) | |
a304e1b8 | 323 | |
6dfc0665 DH |
324 | config DEBUG_FORCE_WEAK_PER_CPU |
325 | bool "Force weak per-cpu definitions" | |
326 | depends on DEBUG_KERNEL | |
8446f1d3 | 327 | help |
6dfc0665 DH |
328 | s390 and alpha require percpu variables in modules to be |
329 | defined weak to work around addressing range issue which | |
330 | puts the following two restrictions on percpu variable | |
331 | definitions. | |
8446f1d3 | 332 | |
6dfc0665 DH |
333 | 1. percpu symbols must be unique whether static or not |
334 | 2. percpu variables can't be defined inside a function | |
8446f1d3 | 335 | |
6dfc0665 DH |
336 | To ensure that generic code follows the above rules, this |
337 | option forces all percpu variables to be defined as weak. | |
5f329089 | 338 | |
6dfc0665 | 339 | endmenu # "Compiler options" |
8446f1d3 | 340 | |
6dfc0665 DH |
341 | config MAGIC_SYSRQ |
342 | bool "Magic SysRq key" | |
343 | depends on !UML | |
344 | help | |
345 | If you say Y here, you will have some control over the system even | |
346 | if the system crashes for example during kernel debugging (e.g., you | |
347 | will be able to flush the buffer cache to disk, reboot the system | |
348 | immediately or dump some status information). This is accomplished | |
349 | by pressing various keys while holding SysRq (Alt+PrintScreen). It | |
350 | also works on a serial console (on PC hardware at least), if you | |
351 | send a BREAK and then within 5 seconds a command keypress. The | |
352 | keys are documented in <file:Documentation/sysrq.txt>. Don't say Y | |
353 | unless you really know what this hack does. | |
8446f1d3 | 354 | |
8eaede49 BH |
355 | config MAGIC_SYSRQ_DEFAULT_ENABLE |
356 | hex "Enable magic SysRq key functions by default" | |
357 | depends on MAGIC_SYSRQ | |
358 | default 0x1 | |
359 | help | |
360 | Specifies which SysRq key functions are enabled by default. | |
361 | This may be set to 1 or 0 to enable or disable them all, or | |
362 | to a bitmask as described in Documentation/sysrq.txt. | |
363 | ||
f346f4b3 AB |
364 | config DEBUG_KERNEL |
365 | bool "Kernel debugging" | |
fef2c9bc | 366 | help |
f346f4b3 AB |
367 | Say Y here if you are developing drivers or trying to debug and |
368 | identify kernel problems. | |
fef2c9bc | 369 | |
0610c8a8 | 370 | menu "Memory Debugging" |
fef2c9bc | 371 | |
0610c8a8 | 372 | source mm/Kconfig.debug |
fef2c9bc | 373 | |
0610c8a8 DH |
374 | config DEBUG_OBJECTS |
375 | bool "Debug object operations" | |
376 | depends on DEBUG_KERNEL | |
9c44bc03 | 377 | help |
0610c8a8 DH |
378 | If you say Y here, additional code will be inserted into the |
379 | kernel to track the life time of various objects and validate | |
380 | the operations on those objects. | |
9c44bc03 | 381 | |
0610c8a8 DH |
382 | config DEBUG_OBJECTS_SELFTEST |
383 | bool "Debug objects selftest" | |
384 | depends on DEBUG_OBJECTS | |
385 | help | |
386 | This enables the selftest of the object debug code. | |
9c44bc03 | 387 | |
0610c8a8 DH |
388 | config DEBUG_OBJECTS_FREE |
389 | bool "Debug objects in freed memory" | |
390 | depends on DEBUG_OBJECTS | |
391 | help | |
392 | This enables checks whether a k/v free operation frees an area | |
393 | which contains an object which has not been deactivated | |
394 | properly. This can make kmalloc/kfree-intensive workloads | |
395 | much slower. | |
3ac7fe5a | 396 | |
c6f3a97f TG |
397 | config DEBUG_OBJECTS_TIMERS |
398 | bool "Debug timer objects" | |
399 | depends on DEBUG_OBJECTS | |
400 | help | |
401 | If you say Y here, additional code will be inserted into the | |
402 | timer routines to track the life time of timer objects and | |
403 | validate the timer operations. | |
404 | ||
dc186ad7 TG |
405 | config DEBUG_OBJECTS_WORK |
406 | bool "Debug work objects" | |
407 | depends on DEBUG_OBJECTS | |
408 | help | |
409 | If you say Y here, additional code will be inserted into the | |
410 | work queue routines to track the life time of work objects and | |
411 | validate the work operations. | |
412 | ||
551d55a9 MD |
413 | config DEBUG_OBJECTS_RCU_HEAD |
414 | bool "Debug RCU callbacks objects" | |
fc2ecf7e | 415 | depends on DEBUG_OBJECTS |
551d55a9 MD |
416 | help |
417 | Enable this to turn on debugging of RCU list heads (call_rcu() usage). | |
418 | ||
e2852ae8 TH |
419 | config DEBUG_OBJECTS_PERCPU_COUNTER |
420 | bool "Debug percpu counter objects" | |
421 | depends on DEBUG_OBJECTS | |
422 | help | |
423 | If you say Y here, additional code will be inserted into the | |
424 | percpu counter routines to track the life time of percpu counter | |
425 | objects and validate the percpu counter operations. | |
426 | ||
3ae70205 IM |
427 | config DEBUG_OBJECTS_ENABLE_DEFAULT |
428 | int "debug_objects bootup default value (0-1)" | |
429 | range 0 1 | |
430 | default "1" | |
431 | depends on DEBUG_OBJECTS | |
432 | help | |
433 | Debug objects boot parameter default value | |
434 | ||
1da177e4 | 435 | config DEBUG_SLAB |
4a2f0acf | 436 | bool "Debug slab memory allocations" |
7d46d9e6 | 437 | depends on DEBUG_KERNEL && SLAB && !KMEMCHECK |
1da177e4 LT |
438 | help |
439 | Say Y here to have the kernel do limited verification on memory | |
440 | allocation as well as poisoning memory on free to catch use of freed | |
441 | memory. This can make kmalloc/kfree-intensive workloads much slower. | |
442 | ||
871751e2 AV |
443 | config DEBUG_SLAB_LEAK |
444 | bool "Memory leak debugging" | |
445 | depends on DEBUG_SLAB | |
446 | ||
f0630fff CL |
447 | config SLUB_DEBUG_ON |
448 | bool "SLUB debugging on by default" | |
7d46d9e6 | 449 | depends on SLUB && SLUB_DEBUG && !KMEMCHECK |
f0630fff CL |
450 | default n |
451 | help | |
452 | Boot with debugging on by default. SLUB boots by default with | |
453 | the runtime debug capabilities switched off. Enabling this is | |
454 | equivalent to specifying the "slub_debug" parameter on boot. | |
455 | There is no support for more fine grained debug control like | |
456 | possible with slub_debug=xxx. SLUB debugging may be switched | |
457 | off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying | |
458 | "slub_debug=-". | |
459 | ||
8ff12cfc CL |
460 | config SLUB_STATS |
461 | default n | |
462 | bool "Enable SLUB performance statistics" | |
ab4d5ed5 | 463 | depends on SLUB && SYSFS |
8ff12cfc CL |
464 | help |
465 | SLUB statistics are useful to debug SLUBs allocation behavior in | |
466 | order find ways to optimize the allocator. This should never be | |
467 | enabled for production use since keeping statistics slows down | |
468 | the allocator by a few percentage points. The slabinfo command | |
469 | supports the determination of the most active slabs to figure | |
470 | out which slabs are relevant to a particular load. | |
471 | Try running: slabinfo -DA | |
472 | ||
b69ec42b CM |
473 | config HAVE_DEBUG_KMEMLEAK |
474 | bool | |
475 | ||
3bba00d7 CM |
476 | config DEBUG_KMEMLEAK |
477 | bool "Kernel memory leak detector" | |
525c1f92 | 478 | depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK |
79e0d9bd | 479 | select DEBUG_FS |
3bba00d7 CM |
480 | select STACKTRACE if STACKTRACE_SUPPORT |
481 | select KALLSYMS | |
b60e26a2 | 482 | select CRC32 |
3bba00d7 CM |
483 | help |
484 | Say Y here if you want to enable the memory leak | |
485 | detector. The memory allocation/freeing is traced in a way | |
486 | similar to the Boehm's conservative garbage collector, the | |
487 | difference being that the orphan objects are not freed but | |
488 | only shown in /sys/kernel/debug/kmemleak. Enabling this | |
489 | feature will introduce an overhead to memory | |
490 | allocations. See Documentation/kmemleak.txt for more | |
491 | details. | |
492 | ||
0610c8a8 DH |
493 | Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances |
494 | of finding leaks due to the slab objects poisoning. | |
495 | ||
496 | In order to access the kmemleak file, debugfs needs to be | |
497 | mounted (usually at /sys/kernel/debug). | |
498 | ||
499 | config DEBUG_KMEMLEAK_EARLY_LOG_SIZE | |
500 | int "Maximum kmemleak early log entries" | |
501 | depends on DEBUG_KMEMLEAK | |
502 | range 200 40000 | |
503 | default 400 | |
504 | help | |
505 | Kmemleak must track all the memory allocations to avoid | |
506 | reporting false positives. Since memory may be allocated or | |
507 | freed before kmemleak is initialised, an early log buffer is | |
508 | used to store these actions. If kmemleak reports "early log | |
509 | buffer exceeded", please increase this value. | |
510 | ||
511 | config DEBUG_KMEMLEAK_TEST | |
512 | tristate "Simple test for the kernel memory leak detector" | |
513 | depends on DEBUG_KMEMLEAK && m | |
514 | help | |
515 | This option enables a module that explicitly leaks memory. | |
516 | ||
517 | If unsure, say N. | |
518 | ||
519 | config DEBUG_KMEMLEAK_DEFAULT_OFF | |
520 | bool "Default kmemleak to off" | |
521 | depends on DEBUG_KMEMLEAK | |
522 | help | |
523 | Say Y here to disable kmemleak by default. It can then be enabled | |
524 | on the command line via kmemleak=on. | |
525 | ||
526 | config DEBUG_STACK_USAGE | |
527 | bool "Stack utilization instrumentation" | |
528 | depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG | |
529 | help | |
530 | Enables the display of the minimum amount of free stack which each | |
531 | task has ever had available in the sysrq-T and sysrq-P debug output. | |
532 | ||
533 | This option will slow down process creation somewhat. | |
534 | ||
535 | config DEBUG_VM | |
536 | bool "Debug VM" | |
537 | depends on DEBUG_KERNEL | |
538 | help | |
539 | Enable this to turn on extended checks in the virtual-memory system | |
540 | that may impact performance. | |
541 | ||
542 | If unsure, say N. | |
543 | ||
4f115147 DB |
544 | config DEBUG_VM_VMACACHE |
545 | bool "Debug VMA caching" | |
546 | depends on DEBUG_VM | |
547 | help | |
548 | Enable this to turn on VMA caching debug information. Doing so | |
549 | can cause significant overhead, so only enable it in non-production | |
550 | environments. | |
551 | ||
552 | If unsure, say N. | |
553 | ||
0610c8a8 DH |
554 | config DEBUG_VM_RB |
555 | bool "Debug VM red-black trees" | |
556 | depends on DEBUG_VM | |
557 | help | |
a663dad6 | 558 | Enable VM red-black tree debugging information and extra validations. |
0610c8a8 DH |
559 | |
560 | If unsure, say N. | |
561 | ||
562 | config DEBUG_VIRTUAL | |
563 | bool "Debug VM translations" | |
564 | depends on DEBUG_KERNEL && X86 | |
565 | help | |
566 | Enable some costly sanity checks in virtual to page code. This can | |
567 | catch mistakes with virt_to_page() and friends. | |
568 | ||
569 | If unsure, say N. | |
570 | ||
571 | config DEBUG_NOMMU_REGIONS | |
572 | bool "Debug the global anon/private NOMMU mapping region tree" | |
573 | depends on DEBUG_KERNEL && !MMU | |
574 | help | |
575 | This option causes the global tree of anonymous and private mapping | |
576 | regions to be regularly checked for invalid topology. | |
577 | ||
578 | config DEBUG_MEMORY_INIT | |
579 | bool "Debug memory initialisation" if EXPERT | |
580 | default !EXPERT | |
581 | help | |
582 | Enable this for additional checks during memory initialisation. | |
583 | The sanity checks verify aspects of the VM such as the memory model | |
584 | and other information provided by the architecture. Verbose | |
585 | information will be printed at KERN_DEBUG loglevel depending | |
586 | on the mminit_loglevel= command-line option. | |
587 | ||
588 | If unsure, say Y | |
589 | ||
590 | config MEMORY_NOTIFIER_ERROR_INJECT | |
591 | tristate "Memory hotplug notifier error injection module" | |
592 | depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION | |
593 | help | |
594 | This option provides the ability to inject artificial errors to | |
595 | memory hotplug notifier chain callbacks. It is controlled through | |
596 | debugfs interface under /sys/kernel/debug/notifier-error-inject/memory | |
597 | ||
598 | If the notifier call chain should be failed with some events | |
599 | notified, write the error code to "actions/<notifier event>/error". | |
600 | ||
601 | Example: Inject memory hotplug offline error (-12 == -ENOMEM) | |
602 | ||
603 | # cd /sys/kernel/debug/notifier-error-inject/memory | |
604 | # echo -12 > actions/MEM_GOING_OFFLINE/error | |
605 | # echo offline > /sys/devices/system/memory/memoryXXX/state | |
606 | bash: echo: write error: Cannot allocate memory | |
607 | ||
608 | To compile this code as a module, choose M here: the module will | |
609 | be called memory-notifier-error-inject. | |
610 | ||
611 | If unsure, say N. | |
612 | ||
613 | config DEBUG_PER_CPU_MAPS | |
614 | bool "Debug access to per_cpu maps" | |
615 | depends on DEBUG_KERNEL | |
616 | depends on SMP | |
617 | help | |
618 | Say Y to verify that the per_cpu map being accessed has | |
619 | been set up. This adds a fair amount of code to kernel memory | |
620 | and decreases performance. | |
621 | ||
622 | Say N if unsure. | |
623 | ||
624 | config DEBUG_HIGHMEM | |
625 | bool "Highmem debugging" | |
626 | depends on DEBUG_KERNEL && HIGHMEM | |
627 | help | |
b1357c9f GU |
628 | This option enables additional error checking for high memory |
629 | systems. Disable for production systems. | |
0610c8a8 DH |
630 | |
631 | config HAVE_DEBUG_STACKOVERFLOW | |
632 | bool | |
633 | ||
634 | config DEBUG_STACKOVERFLOW | |
635 | bool "Check for stack overflows" | |
636 | depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW | |
637 | ---help--- | |
638 | Say Y here if you want to check for overflows of kernel, IRQ | |
edb0ec07 | 639 | and exception stacks (if your architecture uses them). This |
0610c8a8 DH |
640 | option will show detailed messages if free stack space drops |
641 | below a certain limit. | |
642 | ||
643 | These kinds of bugs usually occur when call-chains in the | |
644 | kernel get too deep, especially when interrupts are | |
645 | involved. | |
646 | ||
647 | Use this in cases where you see apparently random memory | |
648 | corruption, especially if it appears in 'struct thread_info' | |
649 | ||
650 | If in doubt, say "N". | |
651 | ||
652 | source "lib/Kconfig.kmemcheck" | |
653 | ||
654 | endmenu # "Memory Debugging" | |
655 | ||
a304e1b8 DW |
656 | config DEBUG_SHIRQ |
657 | bool "Debug shared IRQ handlers" | |
0244ad00 | 658 | depends on DEBUG_KERNEL |
a304e1b8 DW |
659 | help |
660 | Enable this to generate a spurious interrupt as soon as a shared | |
661 | interrupt handler is registered, and just before one is deregistered. | |
662 | Drivers ought to be able to handle interrupts coming in at those | |
663 | points; some don't and need to be caught. | |
664 | ||
92aef8fb DH |
665 | menu "Debug Lockups and Hangs" |
666 | ||
58687acb DZ |
667 | config LOCKUP_DETECTOR |
668 | bool "Detect Hard and Soft Lockups" | |
dea20a3f | 669 | depends on DEBUG_KERNEL && !S390 |
8446f1d3 | 670 | help |
58687acb DZ |
671 | Say Y here to enable the kernel to act as a watchdog to detect |
672 | hard and soft lockups. | |
673 | ||
674 | Softlockups are bugs that cause the kernel to loop in kernel | |
5f329089 | 675 | mode for more than 20 seconds, without giving other tasks a |
58687acb DZ |
676 | chance to run. The current stack trace is displayed upon |
677 | detection and the system will stay locked up. | |
8446f1d3 | 678 | |
58687acb | 679 | Hardlockups are bugs that cause the CPU to loop in kernel mode |
5f329089 | 680 | for more than 10 seconds, without letting other interrupts have a |
58687acb DZ |
681 | chance to run. The current stack trace is displayed upon detection |
682 | and the system will stay locked up. | |
8446f1d3 | 683 | |
58687acb | 684 | The overhead should be minimal. A periodic hrtimer runs to |
5f329089 FLVC |
685 | generate interrupts and kick the watchdog task every 4 seconds. |
686 | An NMI is generated every 10 seconds or so to check for hardlockups. | |
687 | ||
688 | The frequency of hrtimer and NMI events and the soft and hard lockup | |
689 | thresholds can be controlled through the sysctl watchdog_thresh. | |
8446f1d3 | 690 | |
23637d47 | 691 | config HARDLOCKUP_DETECTOR |
8f1f66ed JB |
692 | def_bool y |
693 | depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG | |
694 | depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI | |
8446f1d3 | 695 | |
fef2c9bc DZ |
696 | config BOOTPARAM_HARDLOCKUP_PANIC |
697 | bool "Panic (Reboot) On Hard Lockups" | |
8f1f66ed | 698 | depends on HARDLOCKUP_DETECTOR |
fef2c9bc DZ |
699 | help |
700 | Say Y here to enable the kernel to panic on "hard lockups", | |
701 | which are bugs that cause the kernel to loop in kernel | |
5f329089 FLVC |
702 | mode with interrupts disabled for more than 10 seconds (configurable |
703 | using the watchdog_thresh sysctl). | |
fef2c9bc DZ |
704 | |
705 | Say N if unsure. | |
706 | ||
707 | config BOOTPARAM_HARDLOCKUP_PANIC_VALUE | |
708 | int | |
8f1f66ed | 709 | depends on HARDLOCKUP_DETECTOR |
fef2c9bc DZ |
710 | range 0 1 |
711 | default 0 if !BOOTPARAM_HARDLOCKUP_PANIC | |
712 | default 1 if BOOTPARAM_HARDLOCKUP_PANIC | |
713 | ||
9c44bc03 IM |
714 | config BOOTPARAM_SOFTLOCKUP_PANIC |
715 | bool "Panic (Reboot) On Soft Lockups" | |
89d7ce2a | 716 | depends on LOCKUP_DETECTOR |
9c44bc03 IM |
717 | help |
718 | Say Y here to enable the kernel to panic on "soft lockups", | |
719 | which are bugs that cause the kernel to loop in kernel | |
5f329089 FLVC |
720 | mode for more than 20 seconds (configurable using the watchdog_thresh |
721 | sysctl), without giving other tasks a chance to run. | |
9c44bc03 IM |
722 | |
723 | The panic can be used in combination with panic_timeout, | |
724 | to cause the system to reboot automatically after a | |
725 | lockup has been detected. This feature is useful for | |
726 | high-availability systems that have uptime guarantees and | |
727 | where a lockup must be resolved ASAP. | |
728 | ||
729 | Say N if unsure. | |
730 | ||
731 | config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE | |
732 | int | |
e16bb1d7 | 733 | depends on LOCKUP_DETECTOR |
9c44bc03 IM |
734 | range 0 1 |
735 | default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC | |
736 | default 1 if BOOTPARAM_SOFTLOCKUP_PANIC | |
737 | ||
e162b39a MSB |
738 | config DETECT_HUNG_TASK |
739 | bool "Detect Hung Tasks" | |
740 | depends on DEBUG_KERNEL | |
8edbb83e | 741 | default LOCKUP_DETECTOR |
e162b39a | 742 | help |
0610c8a8 DH |
743 | Say Y here to enable the kernel to detect "hung tasks", |
744 | which are bugs that cause the task to be stuck in | |
745 | uninterruptible "D" state indefinitiley. | |
1da177e4 | 746 | |
0610c8a8 DH |
747 | When a hung task is detected, the kernel will print the |
748 | current stack trace (which you should report), but the | |
749 | task will stay in uninterruptible state. If lockdep is | |
750 | enabled then all held locks will also be reported. This | |
751 | feature has negligible overhead. | |
871751e2 | 752 | |
0610c8a8 DH |
753 | config DEFAULT_HUNG_TASK_TIMEOUT |
754 | int "Default timeout for hung task detection (in seconds)" | |
755 | depends on DETECT_HUNG_TASK | |
756 | default 120 | |
f0630fff | 757 | help |
0610c8a8 DH |
758 | This option controls the default timeout (in seconds) used |
759 | to determine when a task has become non-responsive and should | |
760 | be considered hung. | |
f0630fff | 761 | |
0610c8a8 DH |
762 | It can be adjusted at runtime via the kernel.hung_task_timeout_secs |
763 | sysctl or by writing a value to | |
764 | /proc/sys/kernel/hung_task_timeout_secs. | |
8ff12cfc | 765 | |
0610c8a8 DH |
766 | A timeout of 0 disables the check. The default is two minutes. |
767 | Keeping the default should be fine in most cases. | |
b69ec42b | 768 | |
0610c8a8 DH |
769 | config BOOTPARAM_HUNG_TASK_PANIC |
770 | bool "Panic (Reboot) On Hung Tasks" | |
771 | depends on DETECT_HUNG_TASK | |
3bba00d7 | 772 | help |
0610c8a8 DH |
773 | Say Y here to enable the kernel to panic on "hung tasks", |
774 | which are bugs that cause the kernel to leave a task stuck | |
775 | in uninterruptible "D" state. | |
3bba00d7 | 776 | |
0610c8a8 DH |
777 | The panic can be used in combination with panic_timeout, |
778 | to cause the system to reboot automatically after a | |
779 | hung task has been detected. This feature is useful for | |
780 | high-availability systems that have uptime guarantees and | |
781 | where a hung tasks must be resolved ASAP. | |
bf96d1e3 | 782 | |
0610c8a8 | 783 | Say N if unsure. |
bf96d1e3 | 784 | |
0610c8a8 DH |
785 | config BOOTPARAM_HUNG_TASK_PANIC_VALUE |
786 | int | |
787 | depends on DETECT_HUNG_TASK | |
788 | range 0 1 | |
789 | default 0 if !BOOTPARAM_HUNG_TASK_PANIC | |
790 | default 1 if BOOTPARAM_HUNG_TASK_PANIC | |
3bba00d7 | 791 | |
92aef8fb DH |
792 | endmenu # "Debug lockups and hangs" |
793 | ||
794 | config PANIC_ON_OOPS | |
795 | bool "Panic on Oops" | |
a9d9058a | 796 | help |
92aef8fb DH |
797 | Say Y here to enable the kernel to panic when it oopses. This |
798 | has the same effect as setting oops=panic on the kernel command | |
799 | line. | |
a9d9058a | 800 | |
92aef8fb DH |
801 | This feature is useful to ensure that the kernel does not do |
802 | anything erroneous after an oops which could result in data | |
803 | corruption or other issues. | |
804 | ||
805 | Say N if unsure. | |
806 | ||
807 | config PANIC_ON_OOPS_VALUE | |
808 | int | |
809 | range 0 1 | |
810 | default 0 if !PANIC_ON_OOPS | |
811 | default 1 if PANIC_ON_OOPS | |
812 | ||
5800dc3c JB |
813 | config PANIC_TIMEOUT |
814 | int "panic timeout" | |
815 | default 0 | |
816 | help | |
817 | Set the timeout value (in seconds) until a reboot occurs when the | |
818 | the kernel panics. If n = 0, then we wait forever. A timeout | |
819 | value n > 0 will wait n seconds before rebooting, while a timeout | |
820 | value n < 0 will reboot immediately. | |
821 | ||
0610c8a8 DH |
822 | config SCHED_DEBUG |
823 | bool "Collect scheduler debugging info" | |
824 | depends on DEBUG_KERNEL && PROC_FS | |
825 | default y | |
0822ee4a | 826 | help |
0610c8a8 DH |
827 | If you say Y here, the /proc/sched_debug file will be provided |
828 | that can help debug the scheduler. The runtime overhead of this | |
829 | option is minimal. | |
0822ee4a | 830 | |
0610c8a8 DH |
831 | config SCHEDSTATS |
832 | bool "Collect scheduler statistics" | |
833 | depends on DEBUG_KERNEL && PROC_FS | |
834 | help | |
835 | If you say Y here, additional code will be inserted into the | |
836 | scheduler and related routines to collect statistics about | |
837 | scheduler behavior and provide them in /proc/schedstat. These | |
838 | stats may be useful for both tuning and debugging the scheduler | |
839 | If you aren't debugging the scheduler or trying to tune a specific | |
840 | application, you can say N to avoid the very slight overhead | |
841 | this adds. | |
0822ee4a | 842 | |
0d9e2632 AT |
843 | config SCHED_STACK_END_CHECK |
844 | bool "Detect stack corruption on calls to schedule()" | |
845 | depends on DEBUG_KERNEL | |
846 | default n | |
847 | help | |
848 | This option checks for a stack overrun on calls to schedule(). | |
849 | If the stack end location is found to be over written always panic as | |
850 | the content of the corrupted region can no longer be trusted. | |
851 | This is to ensure no erroneous behaviour occurs which could result in | |
852 | data corruption or a sporadic crash at a later stage once the region | |
853 | is examined. The runtime overhead introduced is minimal. | |
854 | ||
0610c8a8 DH |
855 | config TIMER_STATS |
856 | bool "Collect kernel timers statistics" | |
857 | depends on DEBUG_KERNEL && PROC_FS | |
ab0155a2 | 858 | help |
0610c8a8 DH |
859 | If you say Y here, additional code will be inserted into the |
860 | timer routines to collect statistics about kernel timers being | |
861 | reprogrammed. The statistics can be read from /proc/timer_stats. | |
862 | The statistics collection is started by writing 1 to /proc/timer_stats, | |
863 | writing 0 stops it. This feature is useful to collect information | |
864 | about timer usage patterns in kernel and userspace. This feature | |
865 | is lightweight if enabled in the kernel config but not activated | |
866 | (it defaults to deactivated on bootup and will only be activated | |
867 | if some application like powertop activates it explicitly). | |
ab0155a2 | 868 | |
1da177e4 LT |
869 | config DEBUG_PREEMPT |
870 | bool "Debug preemptible kernel" | |
01deab98 | 871 | depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT |
1da177e4 LT |
872 | default y |
873 | help | |
874 | If you say Y here then the kernel will use a debug variant of the | |
875 | commonly used smp_processor_id() function and will print warnings | |
876 | if kernel code uses it in a preemption-unsafe way. Also, the kernel | |
877 | will detect preemption count underflows. | |
878 | ||
9eade16b DH |
879 | menu "Lock Debugging (spinlocks, mutexes, etc...)" |
880 | ||
e7eebaf6 IM |
881 | config DEBUG_RT_MUTEXES |
882 | bool "RT Mutex debugging, deadlock detection" | |
e7eebaf6 IM |
883 | depends on DEBUG_KERNEL && RT_MUTEXES |
884 | help | |
885 | This allows rt mutex semantics violations and rt mutex related | |
886 | deadlocks (lockups) to be detected and reported automatically. | |
887 | ||
61a87122 TG |
888 | config RT_MUTEX_TESTER |
889 | bool "Built-in scriptable tester for rt-mutexes" | |
6cc620bc | 890 | depends on DEBUG_KERNEL && RT_MUTEXES && BROKEN |
61a87122 TG |
891 | help |
892 | This option enables a rt-mutex tester. | |
893 | ||
1da177e4 | 894 | config DEBUG_SPINLOCK |
4d9f34ad | 895 | bool "Spinlock and rw-lock debugging: basic checks" |
1da177e4 | 896 | depends on DEBUG_KERNEL |
e335e3eb | 897 | select UNINLINE_SPIN_UNLOCK |
1da177e4 LT |
898 | help |
899 | Say Y here and build SMP to catch missing spinlock initialization | |
900 | and certain other kinds of spinlock errors commonly made. This is | |
901 | best used in conjunction with the NMI watchdog so that spinlock | |
902 | deadlocks are also debuggable. | |
903 | ||
4d9f34ad IM |
904 | config DEBUG_MUTEXES |
905 | bool "Mutex debugging: basic checks" | |
906 | depends on DEBUG_KERNEL | |
907 | help | |
908 | This feature allows mutex semantics violations to be detected and | |
909 | reported. | |
910 | ||
23010027 DV |
911 | config DEBUG_WW_MUTEX_SLOWPATH |
912 | bool "Wait/wound mutex debugging: Slowpath testing" | |
913 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT | |
914 | select DEBUG_LOCK_ALLOC | |
915 | select DEBUG_SPINLOCK | |
916 | select DEBUG_MUTEXES | |
917 | help | |
918 | This feature enables slowpath testing for w/w mutex users by | |
919 | injecting additional -EDEADLK wound/backoff cases. Together with | |
920 | the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this | |
921 | will test all possible w/w mutex interface abuse with the | |
922 | exception of simply not acquiring all the required locks. | |
4d692373 RC |
923 | Note that this feature can introduce significant overhead, so |
924 | it really should not be enabled in a production or distro kernel, | |
925 | even a debug kernel. If you are a driver writer, enable it. If | |
926 | you are a distro, do not. | |
23010027 | 927 | |
4d9f34ad IM |
928 | config DEBUG_LOCK_ALLOC |
929 | bool "Lock debugging: detect incorrect freeing of live locks" | |
517e7aa5 | 930 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
931 | select DEBUG_SPINLOCK |
932 | select DEBUG_MUTEXES | |
4d9f34ad IM |
933 | select LOCKDEP |
934 | help | |
935 | This feature will check whether any held lock (spinlock, rwlock, | |
936 | mutex or rwsem) is incorrectly freed by the kernel, via any of the | |
937 | memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), | |
938 | vfree(), etc.), whether a live lock is incorrectly reinitialized via | |
939 | spin_lock_init()/mutex_init()/etc., or whether there is any lock | |
940 | held during task exit. | |
941 | ||
942 | config PROVE_LOCKING | |
943 | bool "Lock debugging: prove locking correctness" | |
517e7aa5 | 944 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
945 | select LOCKDEP |
946 | select DEBUG_SPINLOCK | |
947 | select DEBUG_MUTEXES | |
4d9f34ad | 948 | select DEBUG_LOCK_ALLOC |
46b93b74 | 949 | select TRACE_IRQFLAGS |
4d9f34ad IM |
950 | default n |
951 | help | |
952 | This feature enables the kernel to prove that all locking | |
953 | that occurs in the kernel runtime is mathematically | |
954 | correct: that under no circumstance could an arbitrary (and | |
955 | not yet triggered) combination of observed locking | |
956 | sequences (on an arbitrary number of CPUs, running an | |
957 | arbitrary number of tasks and interrupt contexts) cause a | |
958 | deadlock. | |
959 | ||
960 | In short, this feature enables the kernel to report locking | |
961 | related deadlocks before they actually occur. | |
962 | ||
963 | The proof does not depend on how hard and complex a | |
964 | deadlock scenario would be to trigger: how many | |
965 | participant CPUs, tasks and irq-contexts would be needed | |
966 | for it to trigger. The proof also does not depend on | |
967 | timing: if a race and a resulting deadlock is possible | |
968 | theoretically (no matter how unlikely the race scenario | |
969 | is), it will be proven so and will immediately be | |
970 | reported by the kernel (once the event is observed that | |
971 | makes the deadlock theoretically possible). | |
972 | ||
973 | If a deadlock is impossible (i.e. the locking rules, as | |
974 | observed by the kernel, are mathematically correct), the | |
975 | kernel reports nothing. | |
976 | ||
977 | NOTE: this feature can also be enabled for rwlocks, mutexes | |
978 | and rwsems - in which case all dependencies between these | |
979 | different locking variants are observed and mapped too, and | |
980 | the proof of observed correctness is also maintained for an | |
981 | arbitrary combination of these separate locking variants. | |
982 | ||
214e0aed | 983 | For more details, see Documentation/locking/lockdep-design.txt. |
4d9f34ad IM |
984 | |
985 | config LOCKDEP | |
986 | bool | |
517e7aa5 | 987 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad | 988 | select STACKTRACE |
df2e1ef6 | 989 | select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC && !SCORE |
4d9f34ad IM |
990 | select KALLSYMS |
991 | select KALLSYMS_ALL | |
992 | ||
f20786ff | 993 | config LOCK_STAT |
fdfb870f | 994 | bool "Lock usage statistics" |
f20786ff PZ |
995 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
996 | select LOCKDEP | |
997 | select DEBUG_SPINLOCK | |
998 | select DEBUG_MUTEXES | |
999 | select DEBUG_LOCK_ALLOC | |
1000 | default n | |
1001 | help | |
1002 | This feature enables tracking lock contention points | |
1003 | ||
214e0aed | 1004 | For more details, see Documentation/locking/lockstat.txt |
a560aa48 | 1005 | |
dd8b1cf6 FW |
1006 | This also enables lock events required by "perf lock", |
1007 | subcommand of perf. | |
1008 | If you want to use "perf lock", you also need to turn on | |
1009 | CONFIG_EVENT_TRACING. | |
84c6f88f HM |
1010 | |
1011 | CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. | |
dd8b1cf6 | 1012 | (CONFIG_LOCKDEP defines "acquire" and "release" events.) |
84c6f88f | 1013 | |
4d9f34ad IM |
1014 | config DEBUG_LOCKDEP |
1015 | bool "Lock dependency engine debugging" | |
517e7aa5 | 1016 | depends on DEBUG_KERNEL && LOCKDEP |
4d9f34ad IM |
1017 | help |
1018 | If you say Y here, the lock dependency engine will do | |
1019 | additional runtime checks to debug itself, at the price | |
1020 | of more runtime overhead. | |
1021 | ||
d902db1e FW |
1022 | config DEBUG_ATOMIC_SLEEP |
1023 | bool "Sleep inside atomic section checking" | |
e8f7c70f | 1024 | select PREEMPT_COUNT |
1da177e4 LT |
1025 | depends on DEBUG_KERNEL |
1026 | help | |
1027 | If you say Y here, various routines which may sleep will become very | |
d902db1e FW |
1028 | noisy if they are called inside atomic sections: when a spinlock is |
1029 | held, inside an rcu read side critical section, inside preempt disabled | |
1030 | sections, inside an interrupt, etc... | |
1da177e4 | 1031 | |
cae2ed9a IM |
1032 | config DEBUG_LOCKING_API_SELFTESTS |
1033 | bool "Locking API boot-time self-tests" | |
1034 | depends on DEBUG_KERNEL | |
1035 | help | |
1036 | Say Y here if you want the kernel to run a short self-test during | |
1037 | bootup. The self-test checks whether common types of locking bugs | |
1038 | are detected by debugging mechanisms or not. (if you disable | |
1039 | lock debugging then those bugs wont be detected of course.) | |
1040 | The following locking APIs are covered: spinlocks, rwlocks, | |
1041 | mutexes and rwsems. | |
1042 | ||
0af3fe1e PM |
1043 | config LOCK_TORTURE_TEST |
1044 | tristate "torture tests for locking" | |
1045 | depends on DEBUG_KERNEL | |
1046 | select TORTURE_TEST | |
1047 | default n | |
1048 | help | |
1049 | This option provides a kernel module that runs torture tests | |
1050 | on kernel locking primitives. The kernel module may be built | |
1051 | after the fact on the running kernel to be tested, if desired. | |
1052 | ||
1053 | Say Y here if you want kernel locking-primitive torture tests | |
1054 | to be built into the kernel. | |
1055 | Say M if you want these torture tests to build as a module. | |
1056 | Say N if you are unsure. | |
1057 | ||
9eade16b | 1058 | endmenu # lock debugging |
8637c099 | 1059 | |
9eade16b DH |
1060 | config TRACE_IRQFLAGS |
1061 | bool | |
5ca43f6c | 1062 | help |
9eade16b DH |
1063 | Enables hooks to interrupt enabling and disabling for |
1064 | either tracing or lock debugging. | |
5ca43f6c | 1065 | |
8637c099 | 1066 | config STACKTRACE |
0c38e1fe | 1067 | bool "Stack backtrace support" |
8637c099 | 1068 | depends on STACKTRACE_SUPPORT |
0c38e1fe DJ |
1069 | help |
1070 | This option causes the kernel to create a /proc/pid/stack for | |
1071 | every process, showing its current stack trace. | |
1072 | It is also used by various kernel debugging features that require | |
1073 | stack trace generation. | |
5ca43f6c | 1074 | |
1da177e4 LT |
1075 | config DEBUG_KOBJECT |
1076 | bool "kobject debugging" | |
1077 | depends on DEBUG_KERNEL | |
1078 | help | |
1079 | If you say Y here, some extra kobject debugging messages will be sent | |
1080 | to the syslog. | |
1081 | ||
c817a67e RK |
1082 | config DEBUG_KOBJECT_RELEASE |
1083 | bool "kobject release debugging" | |
2a999aa0 | 1084 | depends on DEBUG_OBJECTS_TIMERS |
c817a67e RK |
1085 | help |
1086 | kobjects are reference counted objects. This means that their | |
1087 | last reference count put is not predictable, and the kobject can | |
1088 | live on past the point at which a driver decides to drop it's | |
1089 | initial reference to the kobject gained on allocation. An | |
1090 | example of this would be a struct device which has just been | |
1091 | unregistered. | |
1092 | ||
1093 | However, some buggy drivers assume that after such an operation, | |
1094 | the memory backing the kobject can be immediately freed. This | |
1095 | goes completely against the principles of a refcounted object. | |
1096 | ||
1097 | If you say Y here, the kernel will delay the release of kobjects | |
1098 | on the last reference count to improve the visibility of this | |
1099 | kind of kobject release bug. | |
1100 | ||
9b2a60c4 CM |
1101 | config HAVE_DEBUG_BUGVERBOSE |
1102 | bool | |
1103 | ||
1da177e4 | 1104 | config DEBUG_BUGVERBOSE |
6a108a14 | 1105 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT |
9b2a60c4 | 1106 | depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE) |
8420e7ef | 1107 | default y |
1da177e4 LT |
1108 | help |
1109 | Say Y here to make BUG() panics output the file name and line number | |
1110 | of the BUG call as well as the EIP and oops trace. This aids | |
1111 | debugging but costs about 70-100K of memory. | |
1112 | ||
199a9afc DJ |
1113 | config DEBUG_LIST |
1114 | bool "Debug linked list manipulation" | |
1115 | depends on DEBUG_KERNEL | |
1116 | help | |
1117 | Enable this to turn on extended checks in the linked-list | |
1118 | walking routines. | |
1119 | ||
1120 | If unsure, say N. | |
1121 | ||
b8cfff68 DS |
1122 | config DEBUG_PI_LIST |
1123 | bool "Debug priority linked list manipulation" | |
1124 | depends on DEBUG_KERNEL | |
1125 | help | |
1126 | Enable this to turn on extended checks in the priority-ordered | |
1127 | linked-list (plist) walking routines. This checks the entire | |
1128 | list multiple times during each manipulation. | |
1129 | ||
1130 | If unsure, say N. | |
1131 | ||
d6ec0842 JA |
1132 | config DEBUG_SG |
1133 | bool "Debug SG table operations" | |
1134 | depends on DEBUG_KERNEL | |
1135 | help | |
1136 | Enable this to turn on checks on scatter-gather tables. This can | |
1137 | help find problems with drivers that do not properly initialize | |
1138 | their sg tables. | |
1139 | ||
1140 | If unsure, say N. | |
1141 | ||
1b2439db AV |
1142 | config DEBUG_NOTIFIERS |
1143 | bool "Debug notifier call chains" | |
1144 | depends on DEBUG_KERNEL | |
1145 | help | |
1146 | Enable this to turn on sanity checking for notifier call chains. | |
1147 | This is most useful for kernel developers to make sure that | |
1148 | modules properly unregister themselves from notifier chains. | |
1149 | This is a relatively cheap check but if you care about maximum | |
1150 | performance, say N. | |
1151 | ||
e0e81739 DH |
1152 | config DEBUG_CREDENTIALS |
1153 | bool "Debug credential management" | |
1154 | depends on DEBUG_KERNEL | |
1155 | help | |
1156 | Enable this to turn on some debug checking for credential | |
1157 | management. The additional code keeps track of the number of | |
1158 | pointers from task_structs to any given cred struct, and checks to | |
1159 | see that this number never exceeds the usage count of the cred | |
1160 | struct. | |
1161 | ||
1162 | Furthermore, if SELinux is enabled, this also checks that the | |
1163 | security pointer in the cred struct is never seen to be invalid. | |
1164 | ||
1165 | If unsure, say N. | |
1166 | ||
2f03e3ca DH |
1167 | menu "RCU Debugging" |
1168 | ||
1169 | config PROVE_RCU | |
1170 | bool "RCU debugging: prove RCU correctness" | |
1171 | depends on PROVE_LOCKING | |
1172 | default n | |
1173 | help | |
1174 | This feature enables lockdep extensions that check for correct | |
1175 | use of RCU APIs. This is currently under development. Say Y | |
1176 | if you want to debug RCU usage or help work on the PROVE_RCU | |
1177 | feature. | |
1178 | ||
1179 | Say N if you are unsure. | |
1180 | ||
1181 | config PROVE_RCU_REPEATEDLY | |
1182 | bool "RCU debugging: don't disable PROVE_RCU on first splat" | |
1183 | depends on PROVE_RCU | |
1184 | default n | |
1185 | help | |
1186 | By itself, PROVE_RCU will disable checking upon issuing the | |
1187 | first warning (or "splat"). This feature prevents such | |
1188 | disabling, allowing multiple RCU-lockdep warnings to be printed | |
1189 | on a single reboot. | |
1190 | ||
1191 | Say Y to allow multiple RCU-lockdep warnings per boot. | |
1192 | ||
1193 | Say N if you are unsure. | |
1194 | ||
2f03e3ca DH |
1195 | config SPARSE_RCU_POINTER |
1196 | bool "RCU debugging: sparse-based checks for pointer usage" | |
1197 | default n | |
1198 | help | |
1199 | This feature enables the __rcu sparse annotation for | |
1200 | RCU-protected pointers. This annotation will cause sparse | |
1201 | to flag any non-RCU used of annotated pointers. This can be | |
1202 | helpful when debugging RCU usage. Please note that this feature | |
1203 | is not intended to enforce code cleanliness; it is instead merely | |
1204 | a debugging aid. | |
1205 | ||
1206 | Say Y to make sparse flag questionable use of RCU-protected pointers | |
1207 | ||
1208 | Say N if you are unsure. | |
1209 | ||
51b1130e PM |
1210 | config TORTURE_TEST |
1211 | tristate | |
1212 | default n | |
1213 | ||
a241ec65 PM |
1214 | config RCU_TORTURE_TEST |
1215 | tristate "torture tests for RCU" | |
1216 | depends on DEBUG_KERNEL | |
51b1130e | 1217 | select TORTURE_TEST |
83fe27ea | 1218 | select SRCU |
a241ec65 PM |
1219 | default n |
1220 | help | |
1221 | This option provides a kernel module that runs torture tests | |
1222 | on the RCU infrastructure. The kernel module may be built | |
1223 | after the fact on the running kernel to be tested, if desired. | |
1224 | ||
31a72bce PM |
1225 | Say Y here if you want RCU torture tests to be built into |
1226 | the kernel. | |
a241ec65 PM |
1227 | Say M if you want the RCU torture tests to build as a module. |
1228 | Say N if you are unsure. | |
8bb31b9d | 1229 | |
31a72bce PM |
1230 | config RCU_TORTURE_TEST_RUNNABLE |
1231 | bool "torture tests for RCU runnable by default" | |
1232 | depends on RCU_TORTURE_TEST = y | |
1233 | default n | |
1234 | help | |
1235 | This option provides a way to build the RCU torture tests | |
1236 | directly into the kernel without them starting up at boot | |
1237 | time. You can use /proc/sys/kernel/rcutorture_runnable | |
1238 | to manually override this setting. This /proc file is | |
1239 | available only when the RCU torture tests have been built | |
1240 | into the kernel. | |
1241 | ||
1242 | Say Y here if you want the RCU torture tests to start during | |
1243 | boot (you probably don't). | |
1244 | Say N here if you want the RCU torture tests to start only | |
1245 | after being manually enabled via /proc. | |
1246 | ||
b163760e PM |
1247 | config RCU_CPU_STALL_TIMEOUT |
1248 | int "RCU CPU stall timeout in seconds" | |
6bfc09e2 | 1249 | depends on RCU_STALL_COMMON |
b163760e | 1250 | range 3 300 |
c896054f | 1251 | default 21 |
b163760e PM |
1252 | help |
1253 | If a given RCU grace period extends more than the specified | |
1254 | number of seconds, a CPU stall warning is printed. If the | |
1255 | RCU grace period persists, additional CPU stall warnings are | |
1256 | printed at more widely spaced intervals. | |
1257 | ||
a858af28 PM |
1258 | config RCU_CPU_STALL_INFO |
1259 | bool "Print additional diagnostics on RCU CPU stall" | |
28f6569a | 1260 | depends on (TREE_RCU || PREEMPT_RCU) && DEBUG_KERNEL |
68158fe2 | 1261 | default y |
a858af28 PM |
1262 | help |
1263 | For each stalled CPU that is aware of the current RCU grace | |
1264 | period, print out additional per-CPU diagnostic information | |
1265 | regarding scheduling-clock ticks, idle state, and, | |
1266 | for RCU_FAST_NO_HZ kernels, idle-entry state. | |
1267 | ||
1268 | Say N if you are unsure. | |
1269 | ||
1270 | Say Y if you want to enable such diagnostics. | |
1271 | ||
5c8806a0 PM |
1272 | config RCU_TRACE |
1273 | bool "Enable tracing for RCU" | |
6dab2778 | 1274 | depends on DEBUG_KERNEL |
52494535 | 1275 | select TRACE_CLOCK |
6dab2778 | 1276 | help |
5c8806a0 PM |
1277 | This option provides tracing in RCU which presents stats |
1278 | in debugfs for debugging RCU implementation. | |
ad118c54 | 1279 | |
5c8806a0 | 1280 | Say Y here if you want to enable RCU tracing |
6dab2778 AV |
1281 | Say N if you are unsure. |
1282 | ||
2f03e3ca DH |
1283 | endmenu # "RCU Debugging" |
1284 | ||
870d6656 TH |
1285 | config DEBUG_BLOCK_EXT_DEVT |
1286 | bool "Force extended block device numbers and spread them" | |
1287 | depends on DEBUG_KERNEL | |
1288 | depends on BLOCK | |
759f8ca3 | 1289 | default n |
870d6656 | 1290 | help |
0e11e342 TH |
1291 | BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON |
1292 | SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT | |
1293 | YOU ARE DOING. Distros, please enable this and fix whatever | |
1294 | is broken. | |
1295 | ||
870d6656 TH |
1296 | Conventionally, block device numbers are allocated from |
1297 | predetermined contiguous area. However, extended block area | |
1298 | may introduce non-contiguous block device numbers. This | |
1299 | option forces most block device numbers to be allocated from | |
1300 | the extended space and spreads them to discover kernel or | |
1301 | userland code paths which assume predetermined contiguous | |
1302 | device number allocation. | |
1303 | ||
55dc7db7 TH |
1304 | Note that turning on this debug option shuffles all the |
1305 | device numbers for all IDE and SCSI devices including libata | |
1306 | ones, so root partition specified using device number | |
1307 | directly (via rdev or root=MAJ:MIN) won't work anymore. | |
1308 | Textual device names (root=/dev/sdXn) will continue to work. | |
1309 | ||
870d6656 TH |
1310 | Say N if you are unsure. |
1311 | ||
8d438288 AM |
1312 | config NOTIFIER_ERROR_INJECTION |
1313 | tristate "Notifier error injection" | |
1314 | depends on DEBUG_KERNEL | |
1315 | select DEBUG_FS | |
1316 | help | |
e41e85cc | 1317 | This option provides the ability to inject artificial errors to |
8d438288 AM |
1318 | specified notifier chain callbacks. It is useful to test the error |
1319 | handling of notifier call chain failures. | |
1320 | ||
1321 | Say N if unsure. | |
1322 | ||
c9d221f8 AM |
1323 | config CPU_NOTIFIER_ERROR_INJECT |
1324 | tristate "CPU notifier error injection module" | |
f5a9f52e | 1325 | depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION |
c9d221f8 AM |
1326 | help |
1327 | This option provides a kernel module that can be used to test | |
e41e85cc | 1328 | the error handling of the cpu notifiers by injecting artificial |
f5a9f52e AM |
1329 | errors to CPU notifier chain callbacks. It is controlled through |
1330 | debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu | |
1331 | ||
1332 | If the notifier call chain should be failed with some events | |
1333 | notified, write the error code to "actions/<notifier event>/error". | |
1334 | ||
1335 | Example: Inject CPU offline error (-1 == -EPERM) | |
1336 | ||
1337 | # cd /sys/kernel/debug/notifier-error-inject/cpu | |
1338 | # echo -1 > actions/CPU_DOWN_PREPARE/error | |
1339 | # echo 0 > /sys/devices/system/cpu/cpu1/online | |
1340 | bash: echo: write error: Operation not permitted | |
c9d221f8 AM |
1341 | |
1342 | To compile this code as a module, choose M here: the module will | |
1343 | be called cpu-notifier-error-inject. | |
1344 | ||
1345 | If unsure, say N. | |
1346 | ||
048b9c35 AM |
1347 | config PM_NOTIFIER_ERROR_INJECT |
1348 | tristate "PM notifier error injection module" | |
1349 | depends on PM && NOTIFIER_ERROR_INJECTION | |
1350 | default m if PM_DEBUG | |
1351 | help | |
e41e85cc | 1352 | This option provides the ability to inject artificial errors to |
048b9c35 AM |
1353 | PM notifier chain callbacks. It is controlled through debugfs |
1354 | interface /sys/kernel/debug/notifier-error-inject/pm | |
1355 | ||
1356 | If the notifier call chain should be failed with some events | |
1357 | notified, write the error code to "actions/<notifier event>/error". | |
1358 | ||
1359 | Example: Inject PM suspend error (-12 = -ENOMEM) | |
1360 | ||
1361 | # cd /sys/kernel/debug/notifier-error-inject/pm/ | |
1362 | # echo -12 > actions/PM_SUSPEND_PREPARE/error | |
1363 | # echo mem > /sys/power/state | |
1364 | bash: echo: write error: Cannot allocate memory | |
1365 | ||
1366 | To compile this code as a module, choose M here: the module will | |
1367 | be called pm-notifier-error-inject. | |
1368 | ||
1369 | If unsure, say N. | |
1370 | ||
d526e85f BH |
1371 | config OF_RECONFIG_NOTIFIER_ERROR_INJECT |
1372 | tristate "OF reconfig notifier error injection module" | |
1373 | depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION | |
08dfb4dd | 1374 | help |
e41e85cc | 1375 | This option provides the ability to inject artificial errors to |
d526e85f | 1376 | OF reconfig notifier chain callbacks. It is controlled |
08dfb4dd | 1377 | through debugfs interface under |
d526e85f | 1378 | /sys/kernel/debug/notifier-error-inject/OF-reconfig/ |
08dfb4dd AM |
1379 | |
1380 | If the notifier call chain should be failed with some events | |
1381 | notified, write the error code to "actions/<notifier event>/error". | |
1382 | ||
1383 | To compile this code as a module, choose M here: the module will | |
e12a95f4 | 1384 | be called of-reconfig-notifier-error-inject. |
08dfb4dd AM |
1385 | |
1386 | If unsure, say N. | |
1387 | ||
6ff1cb35 | 1388 | config FAULT_INJECTION |
1ab8509a AM |
1389 | bool "Fault-injection framework" |
1390 | depends on DEBUG_KERNEL | |
329409ae AM |
1391 | help |
1392 | Provide fault-injection framework. | |
1393 | For more details, see Documentation/fault-injection/. | |
6ff1cb35 | 1394 | |
8a8b6502 | 1395 | config FAILSLAB |
1ab8509a AM |
1396 | bool "Fault-injection capability for kmalloc" |
1397 | depends on FAULT_INJECTION | |
773ff60e | 1398 | depends on SLAB || SLUB |
8a8b6502 | 1399 | help |
1ab8509a | 1400 | Provide fault-injection capability for kmalloc. |
8a8b6502 | 1401 | |
933e312e AM |
1402 | config FAIL_PAGE_ALLOC |
1403 | bool "Fault-injection capabilitiy for alloc_pages()" | |
1ab8509a | 1404 | depends on FAULT_INJECTION |
933e312e | 1405 | help |
1ab8509a | 1406 | Provide fault-injection capability for alloc_pages(). |
933e312e | 1407 | |
c17bb495 | 1408 | config FAIL_MAKE_REQUEST |
86327d19 | 1409 | bool "Fault-injection capability for disk IO" |
581d4e28 | 1410 | depends on FAULT_INJECTION && BLOCK |
c17bb495 | 1411 | help |
1ab8509a | 1412 | Provide fault-injection capability for disk IO. |
c17bb495 | 1413 | |
581d4e28 | 1414 | config FAIL_IO_TIMEOUT |
f4d01439 | 1415 | bool "Fault-injection capability for faking disk interrupts" |
581d4e28 JA |
1416 | depends on FAULT_INJECTION && BLOCK |
1417 | help | |
1418 | Provide fault-injection capability on end IO handling. This | |
1419 | will make the block layer "forget" an interrupt as configured, | |
1420 | thus exercising the error handling. | |
1421 | ||
1422 | Only works with drivers that use the generic timeout handling, | |
1423 | for others it wont do anything. | |
1424 | ||
1b676f70 PF |
1425 | config FAIL_MMC_REQUEST |
1426 | bool "Fault-injection capability for MMC IO" | |
1427 | select DEBUG_FS | |
1428 | depends on FAULT_INJECTION && MMC | |
1429 | help | |
1430 | Provide fault-injection capability for MMC IO. | |
1431 | This will make the mmc core return data errors. This is | |
1432 | useful to test the error handling in the mmc block device | |
1433 | and to test how the mmc host driver handles retries from | |
1434 | the block device. | |
1435 | ||
6ff1cb35 AM |
1436 | config FAULT_INJECTION_DEBUG_FS |
1437 | bool "Debugfs entries for fault-injection capabilities" | |
1ab8509a | 1438 | depends on FAULT_INJECTION && SYSFS && DEBUG_FS |
6ff1cb35 | 1439 | help |
1ab8509a | 1440 | Enable configuration of fault-injection capabilities via debugfs. |
1df49008 AM |
1441 | |
1442 | config FAULT_INJECTION_STACKTRACE_FILTER | |
1443 | bool "stacktrace filter for fault-injection capabilities" | |
1444 | depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT | |
6d690dca | 1445 | depends on !X86_64 |
1df49008 | 1446 | select STACKTRACE |
df2e1ef6 | 1447 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !SCORE |
1df49008 AM |
1448 | help |
1449 | Provide stacktrace filter for fault-injection capabilities | |
267c4025 | 1450 | |
9745512c AV |
1451 | config LATENCYTOP |
1452 | bool "Latency measuring infrastructure" | |
625fdcaa RD |
1453 | depends on HAVE_LATENCYTOP_SUPPORT |
1454 | depends on DEBUG_KERNEL | |
1455 | depends on STACKTRACE_SUPPORT | |
1456 | depends on PROC_FS | |
cc80ae38 | 1457 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC |
9745512c AV |
1458 | select KALLSYMS |
1459 | select KALLSYMS_ALL | |
1460 | select STACKTRACE | |
1461 | select SCHEDSTATS | |
1462 | select SCHED_DEBUG | |
9745512c AV |
1463 | help |
1464 | Enable this option if you want to use the LatencyTOP tool | |
1465 | to find out which userspace is blocking on what kernel operations. | |
1466 | ||
446f24d1 SB |
1467 | config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS |
1468 | bool | |
1469 | ||
1470 | config DEBUG_STRICT_USER_COPY_CHECKS | |
1471 | bool "Strict user copy size checks" | |
1472 | depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS | |
1473 | depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING | |
1474 | help | |
1475 | Enabling this option turns a certain set of sanity checks for user | |
1476 | copy operations into compile time failures. | |
1477 | ||
1478 | The copy_from_user() etc checks are there to help test if there | |
1479 | are sufficient security checks on the length argument of | |
1480 | the copy operation, by having gcc prove that the argument is | |
1481 | within bounds. | |
1482 | ||
1483 | If unsure, say N. | |
1484 | ||
16444a8a ACM |
1485 | source kernel/trace/Kconfig |
1486 | ||
881c5149 DH |
1487 | menu "Runtime Testing" |
1488 | ||
1489 | config LKDTM | |
1490 | tristate "Linux Kernel Dump Test Tool Module" | |
1491 | depends on DEBUG_FS | |
1492 | depends on BLOCK | |
1493 | default n | |
1494 | help | |
1495 | This module enables testing of the different dumping mechanisms by | |
1496 | inducing system failures at predefined crash points. | |
1497 | If you don't need it: say N | |
1498 | Choose M here to compile this code as a module. The module will be | |
1499 | called lkdtm. | |
1500 | ||
1501 | Documentation on how to use the module can be found in | |
1502 | Documentation/fault-injection/provoke-crashes.txt | |
1503 | ||
1504 | config TEST_LIST_SORT | |
1505 | bool "Linked list sorting test" | |
1506 | depends on DEBUG_KERNEL | |
1507 | help | |
1508 | Enable this to turn on 'list_sort()' function test. This test is | |
1509 | executed only once during system boot, so affects only boot time. | |
1510 | ||
1511 | If unsure, say N. | |
1512 | ||
1513 | config KPROBES_SANITY_TEST | |
1514 | bool "Kprobes sanity tests" | |
1515 | depends on DEBUG_KERNEL | |
1516 | depends on KPROBES | |
1517 | default n | |
1518 | help | |
1519 | This option provides for testing basic kprobes functionality on | |
1520 | boot. A sample kprobe, jprobe and kretprobe are inserted and | |
1521 | verified for functionality. | |
1522 | ||
1523 | Say N if you are unsure. | |
1524 | ||
1525 | config BACKTRACE_SELF_TEST | |
1526 | tristate "Self test for the backtrace code" | |
1527 | depends on DEBUG_KERNEL | |
1528 | default n | |
1529 | help | |
1530 | This option provides a kernel module that can be used to test | |
1531 | the kernel stack backtrace code. This option is not useful | |
1532 | for distributions or general kernels, but only for kernel | |
1533 | developers working on architecture code. | |
1534 | ||
1535 | Note that if you want to also test saved backtraces, you will | |
1536 | have to enable STACKTRACE as well. | |
1537 | ||
1538 | Say N if you are unsure. | |
1539 | ||
910a742d ML |
1540 | config RBTREE_TEST |
1541 | tristate "Red-Black tree test" | |
7c993e11 | 1542 | depends on DEBUG_KERNEL |
910a742d ML |
1543 | help |
1544 | A benchmark measuring the performance of the rbtree library. | |
1545 | Also includes rbtree invariant checks. | |
1546 | ||
fff3fd8a ML |
1547 | config INTERVAL_TREE_TEST |
1548 | tristate "Interval tree test" | |
1549 | depends on m && DEBUG_KERNEL | |
a88cc108 | 1550 | select INTERVAL_TREE |
fff3fd8a ML |
1551 | help |
1552 | A benchmark measuring the performance of the interval tree library | |
1553 | ||
623fd807 GT |
1554 | config PERCPU_TEST |
1555 | tristate "Per cpu operations test" | |
1556 | depends on m && DEBUG_KERNEL | |
1557 | help | |
1558 | Enable this option to build test module which validates per-cpu | |
1559 | operations. | |
1560 | ||
1561 | If unsure, say N. | |
1562 | ||
881c5149 DH |
1563 | config ATOMIC64_SELFTEST |
1564 | bool "Perform an atomic64_t self-test at boot" | |
1565 | help | |
1566 | Enable this option to test the atomic64_t functions at boot. | |
1567 | ||
1568 | If unsure, say N. | |
1569 | ||
1570 | config ASYNC_RAID6_TEST | |
1571 | tristate "Self test for hardware accelerated raid6 recovery" | |
1572 | depends on ASYNC_RAID6_RECOV | |
1573 | select ASYNC_MEMCPY | |
1574 | ---help--- | |
1575 | This is a one-shot self test that permutes through the | |
1576 | recovery of all the possible two disk failure scenarios for a | |
1577 | N-disk array. Recovery is performed with the asynchronous | |
1578 | raid6 recovery routines, and will optionally use an offload | |
1579 | engine if one is available. | |
1580 | ||
1581 | If unsure, say N. | |
1582 | ||
64d1d77a AS |
1583 | config TEST_HEXDUMP |
1584 | tristate "Test functions located in the hexdump module at runtime" | |
1585 | ||
881c5149 DH |
1586 | config TEST_STRING_HELPERS |
1587 | tristate "Test functions located in the string_helpers module at runtime" | |
1588 | ||
1589 | config TEST_KSTRTOX | |
1590 | tristate "Test kstrto*() family of functions at runtime" | |
1591 | ||
7e1e7763 | 1592 | config TEST_RHASHTABLE |
9d6dbe1b | 1593 | tristate "Perform selftest on resizable hash table" |
7e1e7763 TG |
1594 | default n |
1595 | help | |
1596 | Enable this option to test the rhashtable functions at boot. | |
1597 | ||
1598 | If unsure, say N. | |
1599 | ||
881c5149 DH |
1600 | endmenu # runtime tests |
1601 | ||
f212ec4b | 1602 | config PROVIDE_OHCI1394_DMA_INIT |
080de8c2 | 1603 | bool "Remote debugging over FireWire early on boot" |
f212ec4b BK |
1604 | depends on PCI && X86 |
1605 | help | |
1606 | If you want to debug problems which hang or crash the kernel early | |
1607 | on boot and the crashing machine has a FireWire port, you can use | |
1608 | this feature to remotely access the memory of the crashed machine | |
1609 | over FireWire. This employs remote DMA as part of the OHCI1394 | |
1610 | specification which is now the standard for FireWire controllers. | |
1611 | ||
1612 | With remote DMA, you can monitor the printk buffer remotely using | |
1613 | firescope and access all memory below 4GB using fireproxy from gdb. | |
1614 | Even controlling a kernel debugger is possible using remote DMA. | |
1615 | ||
1616 | Usage: | |
1617 | ||
1618 | If ohci1394_dma=early is used as boot parameter, it will initialize | |
1619 | all OHCI1394 controllers which are found in the PCI config space. | |
1620 | ||
1621 | As all changes to the FireWire bus such as enabling and disabling | |
1622 | devices cause a bus reset and thereby disable remote DMA for all | |
1623 | devices, be sure to have the cable plugged and FireWire enabled on | |
1624 | the debugging host before booting the debug target for debugging. | |
1625 | ||
1626 | This code (~1k) is freed after boot. By then, the firewire stack | |
1627 | in charge of the OHCI-1394 controllers should be used instead. | |
1628 | ||
1629 | See Documentation/debugging-via-ohci1394.txt for more information. | |
9745512c | 1630 | |
152de30b | 1631 | config BUILD_DOCSRC |
3794f3e8 RD |
1632 | bool "Build targets in Documentation/ tree" |
1633 | depends on HEADERS_CHECK | |
1634 | help | |
1635 | This option attempts to build objects from the source files in the | |
1636 | kernel Documentation/ tree. | |
1637 | ||
1638 | Say N if you are unsure. | |
1639 | ||
5ee00bd4 JR |
1640 | config DMA_API_DEBUG |
1641 | bool "Enable debugging of DMA-API usage" | |
1642 | depends on HAVE_DMA_API_DEBUG | |
1643 | help | |
1644 | Enable this option to debug the use of the DMA API by device drivers. | |
1645 | With this option you will be able to detect common bugs in device | |
1646 | drivers like double-freeing of DMA mappings or freeing mappings that | |
1647 | were never allocated. | |
0abdd7a8 DW |
1648 | |
1649 | This also attempts to catch cases where a page owned by DMA is | |
1650 | accessed by the cpu in a way that could cause data corruption. For | |
1651 | example, this enables cow_user_page() to check that the source page is | |
1652 | not undergoing DMA. | |
1653 | ||
1654 | This option causes a performance degradation. Use only if you want to | |
1655 | debug device drivers and dma interactions. | |
1656 | ||
1657 | If unsure, say N. | |
346e15be | 1658 | |
8a6f0b47 | 1659 | config TEST_LKM |
93e9ef83 KC |
1660 | tristate "Test module loading with 'hello world' module" |
1661 | default n | |
1662 | depends on m | |
1663 | help | |
1664 | This builds the "test_module" module that emits "Hello, world" | |
1665 | on printk when loaded. It is designed to be used for basic | |
1666 | evaluation of the module loading subsystem (for example when | |
1667 | validating module verification). It lacks any extra dependencies, | |
1668 | and will not normally be loaded by the system unless explicitly | |
1669 | requested by name. | |
1670 | ||
1671 | If unsure, say N. | |
1672 | ||
3e2a4c18 KC |
1673 | config TEST_USER_COPY |
1674 | tristate "Test user/kernel boundary protections" | |
1675 | default n | |
1676 | depends on m | |
1677 | help | |
1678 | This builds the "test_user_copy" module that runs sanity checks | |
1679 | on the copy_to/from_user infrastructure, making sure basic | |
1680 | user/kernel boundary testing is working. If it fails to load, | |
1681 | a regression has been detected in the user/kernel memory boundary | |
1682 | protections. | |
1683 | ||
1684 | If unsure, say N. | |
1685 | ||
64a8946b AS |
1686 | config TEST_BPF |
1687 | tristate "Test BPF filter functionality" | |
1688 | default n | |
98920ba6 | 1689 | depends on m && NET |
64a8946b AS |
1690 | help |
1691 | This builds the "test_bpf" module that runs various test vectors | |
1692 | against the BPF interpreter or BPF JIT compiler depending on the | |
1693 | current setting. This is in particular useful for BPF JIT compiler | |
1694 | development, but also to run regression tests against changes in | |
3c731eba AS |
1695 | the interpreter code. It also enables test stubs for eBPF maps and |
1696 | verifier used by user space verifier testsuite. | |
64a8946b AS |
1697 | |
1698 | If unsure, say N. | |
1699 | ||
0a8adf58 KC |
1700 | config TEST_FIRMWARE |
1701 | tristate "Test firmware loading via userspace interface" | |
1702 | default n | |
1703 | depends on FW_LOADER | |
1704 | help | |
1705 | This builds the "test_firmware" module that creates a userspace | |
1706 | interface for testing firmware loading. This can be used to | |
1707 | control the triggering of firmware loading without needing an | |
1708 | actual firmware-using device. The contents can be rechecked by | |
1709 | userspace. | |
1710 | ||
1711 | If unsure, say N. | |
1712 | ||
e704f93a DR |
1713 | config TEST_UDELAY |
1714 | tristate "udelay test driver" | |
1715 | default n | |
1716 | help | |
1717 | This builds the "udelay_test" module that helps to make sure | |
1718 | that udelay() is working properly. | |
1719 | ||
1720 | If unsure, say N. | |
1721 | ||
267c4025 | 1722 | source "samples/Kconfig" |
dc7d5527 JW |
1723 | |
1724 | source "lib/Kconfig.kgdb" | |
0a4af3b0 | 1725 |