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 | |
1cac41cb MB |
18 | config PRINTK_PROCESS |
19 | bool "Show process information on printks" | |
20 | depends on PRINTK | |
21 | help | |
22 | Selecting this option causes process to be | |
23 | included in printk output. Or add printk.process=1 at boot-time. | |
24 | ||
42a9dc0b | 25 | config MESSAGE_LOGLEVEL_DEFAULT |
5af5bcb8 MSB |
26 | int "Default message log level (1-7)" |
27 | range 1 7 | |
28 | default "4" | |
29 | help | |
30 | Default log level for printk statements with no specified priority. | |
31 | ||
32 | This was hard-coded to KERN_WARNING since at least 2.6.10 but folks | |
33 | that are auditing their logs closely may want to set it to a lower | |
34 | priority. | |
35 | ||
604ff0dc DH |
36 | config BOOT_PRINTK_DELAY |
37 | bool "Delay each boot printk message by N milliseconds" | |
38 | depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY | |
39 | help | |
40 | This build option allows you to read kernel boot messages | |
41 | by inserting a short delay after each one. The delay is | |
42 | specified in milliseconds on the kernel command line, | |
43 | using "boot_delay=N". | |
44 | ||
45 | It is likely that you would also need to use "lpj=M" to preset | |
46 | the "loops per jiffie" value. | |
47 | See a previous boot log for the "lpj" value to use for your | |
48 | system, and then set "lpj=M" before setting "boot_delay=N". | |
49 | NOTE: Using this option may adversely affect SMP systems. | |
50 | I.e., processors other than the first one may not boot up. | |
51 | BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect | |
52 | what it believes to be lockup conditions. | |
53 | ||
54 | config DYNAMIC_DEBUG | |
55 | bool "Enable dynamic printk() support" | |
56 | default n | |
57 | depends on PRINTK | |
58 | depends on DEBUG_FS | |
59 | help | |
60 | ||
61 | Compiles debug level messages into the kernel, which would not | |
62 | otherwise be available at runtime. These messages can then be | |
63 | enabled/disabled based on various levels of scope - per source file, | |
64 | function, module, format string, and line number. This mechanism | |
65 | implicitly compiles in all pr_debug() and dev_dbg() calls, which | |
66 | enlarges the kernel text size by about 2%. | |
67 | ||
68 | If a source file is compiled with DEBUG flag set, any | |
69 | pr_debug() calls in it are enabled by default, but can be | |
70 | disabled at runtime as below. Note that DEBUG flag is | |
71 | turned on by many CONFIG_*DEBUG* options. | |
72 | ||
73 | Usage: | |
74 | ||
75 | Dynamic debugging is controlled via the 'dynamic_debug/control' file, | |
76 | which is contained in the 'debugfs' filesystem. Thus, the debugfs | |
77 | filesystem must first be mounted before making use of this feature. | |
78 | We refer the control file as: <debugfs>/dynamic_debug/control. This | |
79 | file contains a list of the debug statements that can be enabled. The | |
80 | format for each line of the file is: | |
81 | ||
82 | filename:lineno [module]function flags format | |
83 | ||
84 | filename : source file of the debug statement | |
85 | lineno : line number of the debug statement | |
86 | module : module that contains the debug statement | |
87 | function : function that contains the debug statement | |
88 | flags : '=p' means the line is turned 'on' for printing | |
89 | format : the format used for the debug statement | |
90 | ||
91 | From a live system: | |
92 | ||
93 | nullarbor:~ # cat <debugfs>/dynamic_debug/control | |
94 | # filename:lineno [module]function flags format | |
95 | fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012" | |
96 | fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012" | |
97 | fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012" | |
98 | ||
99 | Example usage: | |
100 | ||
101 | // enable the message at line 1603 of file svcsock.c | |
102 | nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' > | |
103 | <debugfs>/dynamic_debug/control | |
104 | ||
105 | // enable all the messages in file svcsock.c | |
106 | nullarbor:~ # echo -n 'file svcsock.c +p' > | |
107 | <debugfs>/dynamic_debug/control | |
108 | ||
109 | // enable all the messages in the NFS server module | |
110 | nullarbor:~ # echo -n 'module nfsd +p' > | |
111 | <debugfs>/dynamic_debug/control | |
112 | ||
113 | // enable all 12 messages in the function svc_process() | |
114 | nullarbor:~ # echo -n 'func svc_process +p' > | |
115 | <debugfs>/dynamic_debug/control | |
116 | ||
117 | // disable all 12 messages in the function svc_process() | |
118 | nullarbor:~ # echo -n 'func svc_process -p' > | |
119 | <debugfs>/dynamic_debug/control | |
120 | ||
121 | See Documentation/dynamic-debug-howto.txt for additional information. | |
122 | ||
123 | endmenu # "printk and dmesg options" | |
124 | ||
6dfc0665 DH |
125 | menu "Compile-time checks and compiler options" |
126 | ||
127 | config DEBUG_INFO | |
128 | bool "Compile the kernel with debug info" | |
12b13835 | 129 | depends on DEBUG_KERNEL && !COMPILE_TEST |
6dfc0665 DH |
130 | help |
131 | If you say Y here the resulting kernel image will include | |
132 | debugging info resulting in a larger kernel image. | |
133 | This adds debug symbols to the kernel and modules (gcc -g), and | |
134 | is needed if you intend to use kernel crashdump or binary object | |
135 | tools like crash, kgdb, LKCD, gdb, etc on the kernel. | |
136 | Say Y here only if you plan to debug the kernel. | |
137 | ||
138 | If unsure, say N. | |
139 | ||
140 | config DEBUG_INFO_REDUCED | |
141 | bool "Reduce debugging information" | |
142 | depends on DEBUG_INFO | |
143 | help | |
144 | If you say Y here gcc is instructed to generate less debugging | |
145 | information for structure types. This means that tools that | |
146 | need full debugging information (like kgdb or systemtap) won't | |
147 | be happy. But if you merely need debugging information to | |
148 | resolve line numbers there is no loss. Advantage is that | |
149 | build directory object sizes shrink dramatically over a full | |
150 | DEBUG_INFO build and compile times are reduced too. | |
151 | Only works with newer gcc versions. | |
152 | ||
866ced95 AK |
153 | config DEBUG_INFO_SPLIT |
154 | bool "Produce split debuginfo in .dwo files" | |
623f4fcd | 155 | depends on DEBUG_INFO && !FRV |
866ced95 AK |
156 | help |
157 | Generate debug info into separate .dwo files. This significantly | |
158 | reduces the build directory size for builds with DEBUG_INFO, | |
159 | because it stores the information only once on disk in .dwo | |
160 | files instead of multiple times in object files and executables. | |
161 | In addition the debug information is also compressed. | |
162 | ||
163 | Requires recent gcc (4.7+) and recent gdb/binutils. | |
164 | Any tool that packages or reads debug information would need | |
165 | to know about the .dwo files and include them. | |
166 | Incompatible with older versions of ccache. | |
167 | ||
bfaf2dd3 AK |
168 | config DEBUG_INFO_DWARF4 |
169 | bool "Generate dwarf4 debuginfo" | |
170 | depends on DEBUG_INFO | |
171 | help | |
172 | Generate dwarf4 debug info. This requires recent versions | |
173 | of gcc and gdb. It makes the debug information larger. | |
174 | But it significantly improves the success of resolving | |
175 | variables in gdb on optimized code. | |
176 | ||
3ee7b3fa JK |
177 | config GDB_SCRIPTS |
178 | bool "Provide GDB scripts for kernel debugging" | |
179 | depends on DEBUG_INFO | |
180 | help | |
181 | This creates the required links to GDB helper scripts in the | |
182 | build directory. If you load vmlinux into gdb, the helper | |
183 | scripts will be automatically imported by gdb as well, and | |
184 | additional functions are available to analyze a Linux kernel | |
185 | instance. See Documentation/gdb-kernel-debugging.txt for further | |
186 | details. | |
187 | ||
de488443 JG |
188 | config ENABLE_WARN_DEPRECATED |
189 | bool "Enable __deprecated logic" | |
190 | default y | |
191 | help | |
192 | Enable the __deprecated logic in the kernel build. | |
193 | Disable this to suppress the "warning: 'foo' is deprecated | |
194 | (declared at kernel/power/somefile.c:1234)" messages. | |
195 | ||
cebc04ba AM |
196 | config ENABLE_MUST_CHECK |
197 | bool "Enable __must_check logic" | |
198 | default y | |
199 | help | |
200 | Enable the __must_check logic in the kernel build. Disable this to | |
201 | suppress the "warning: ignoring return value of 'foo', declared with | |
202 | attribute warn_unused_result" messages. | |
1da177e4 | 203 | |
35bb5b1e AK |
204 | config FRAME_WARN |
205 | int "Warn for stack frames larger than (needs gcc 4.4)" | |
206 | range 0 8192 | |
3f181b4d | 207 | default 0 if KASAN |
35bb5b1e AK |
208 | default 1024 if !64BIT |
209 | default 2048 if 64BIT | |
210 | help | |
211 | Tell gcc to warn at build time for stack frames larger than this. | |
212 | Setting this too low will cause a lot of warnings. | |
213 | Setting it to 0 disables the warning. | |
214 | Requires gcc 4.4 | |
215 | ||
99657c78 RD |
216 | config STRIP_ASM_SYMS |
217 | bool "Strip assembler-generated symbols during link" | |
218 | default n | |
219 | help | |
220 | Strip internal assembler-generated symbols during a link (symbols | |
221 | that look like '.Lxxx') so they don't pollute the output of | |
222 | get_wchan() and suchlike. | |
223 | ||
1873e870 AK |
224 | config READABLE_ASM |
225 | bool "Generate readable assembler code" | |
226 | depends on DEBUG_KERNEL | |
227 | help | |
228 | Disable some compiler optimizations that tend to generate human unreadable | |
229 | assembler output. This may make the kernel slightly slower, but it helps | |
230 | to keep kernel developers who have to stare a lot at assembler listings | |
231 | sane. | |
232 | ||
f71d20e9 AV |
233 | config UNUSED_SYMBOLS |
234 | bool "Enable unused/obsolete exported symbols" | |
235 | default y if X86 | |
236 | help | |
237 | Unused but exported symbols make the kernel needlessly bigger. For | |
238 | that reason most of these unused exports will soon be removed. This | |
239 | option is provided temporarily to provide a transition period in case | |
240 | some external kernel module needs one of these symbols anyway. If you | |
241 | encounter such a case in your module, consider if you are actually | |
242 | using the right API. (rationale: since nobody in the kernel is using | |
243 | this in a module, there is a pretty good chance it's actually the | |
244 | wrong interface to use). If you really need the symbol, please send a | |
245 | mail to the linux kernel mailing list mentioning the symbol and why | |
246 | you really need it, and what the merge plan to the mainline kernel for | |
247 | your module is. | |
248 | ||
48c96a36 JK |
249 | config PAGE_OWNER |
250 | bool "Track page owner" | |
251 | depends on DEBUG_KERNEL && STACKTRACE_SUPPORT | |
252 | select DEBUG_FS | |
253 | select STACKTRACE | |
254 | select PAGE_EXTENSION | |
255 | help | |
256 | This keeps track of what call chain is the owner of a page, may | |
257 | help to find bare alloc_page(s) leaks. Even if you include this | |
258 | feature on your build, it is disabled in default. You should pass | |
259 | "page_owner=on" to boot parameter in order to enable it. Eats | |
260 | a fair amount of memory if enabled. See tools/vm/page_owner_sort.c | |
261 | for user-space helper. | |
262 | ||
263 | If unsure, say N. | |
264 | ||
bf4735a4 DM |
265 | config DEBUG_FS |
266 | bool "Debug Filesystem" | |
bf4735a4 DM |
267 | help |
268 | debugfs is a virtual file system that kernel developers use to put | |
269 | debugging files into. Enable this option to be able to read and | |
270 | write to these files. | |
271 | ||
ff543332 RD |
272 | For detailed documentation on the debugfs API, see |
273 | Documentation/DocBook/filesystems. | |
274 | ||
bf4735a4 DM |
275 | If unsure, say N. |
276 | ||
277 | config HEADERS_CHECK | |
278 | bool "Run 'make headers_check' when building vmlinux" | |
279 | depends on !UML | |
280 | help | |
281 | This option will extract the user-visible kernel headers whenever | |
282 | building the kernel, and will run basic sanity checks on them to | |
283 | ensure that exported files do not attempt to include files which | |
284 | were not exported, etc. | |
285 | ||
286 | If you're making modifications to header files which are | |
287 | relevant for userspace, say 'Y', and check the headers | |
288 | exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in | |
289 | your build tree), to make sure they're suitable. | |
290 | ||
91341d4b SR |
291 | config DEBUG_SECTION_MISMATCH |
292 | bool "Enable full Section mismatch analysis" | |
91341d4b SR |
293 | help |
294 | The section mismatch analysis checks if there are illegal | |
295 | references from one section to another section. | |
e809ab01 MW |
296 | During linktime or runtime, some sections are dropped; |
297 | any use of code/data previously in these sections would | |
91341d4b | 298 | most likely result in an oops. |
e809ab01 | 299 | In the code, functions and variables are annotated with |
0db0628d | 300 | __init,, etc. (see the full list in include/linux/init.h), |
d6fbfa4f | 301 | which results in the code/data being placed in specific sections. |
e809ab01 MW |
302 | The section mismatch analysis is always performed after a full |
303 | kernel build, and enabling this option causes the following | |
304 | additional steps to occur: | |
305 | - Add the option -fno-inline-functions-called-once to gcc commands. | |
306 | When inlining a function annotated with __init in a non-init | |
307 | function, we would lose the section information and thus | |
91341d4b | 308 | the analysis would not catch the illegal reference. |
e809ab01 MW |
309 | This option tells gcc to inline less (but it does result in |
310 | a larger kernel). | |
311 | - Run the section mismatch analysis for each module/built-in.o file. | |
312 | When we run the section mismatch analysis on vmlinux.o, we | |
d6fbfa4f | 313 | lose valueble information about where the mismatch was |
91341d4b SR |
314 | introduced. |
315 | Running the analysis for each module/built-in.o file | |
e809ab01 MW |
316 | tells where the mismatch happens much closer to the |
317 | source. The drawback is that the same mismatch is | |
318 | reported at least twice. | |
319 | - Enable verbose reporting from modpost in order to help resolve | |
320 | the section mismatches that are reported. | |
91341d4b | 321 | |
47490ec1 NB |
322 | config SECTION_MISMATCH_WARN_ONLY |
323 | bool "Make section mismatch errors non-fatal" | |
324 | default y | |
325 | help | |
326 | If you say N here, the build process will fail if there are any | |
327 | section mismatch, instead of just throwing warnings. | |
328 | ||
329 | If unsure, say Y. | |
330 | ||
6dfc0665 DH |
331 | # |
332 | # Select this config option from the architecture Kconfig, if it | |
333 | # is preferred to always offer frame pointers as a config | |
334 | # option on the architecture (regardless of KERNEL_DEBUG): | |
335 | # | |
336 | config ARCH_WANT_FRAME_POINTERS | |
337 | bool | |
f346f4b3 | 338 | help |
f346f4b3 | 339 | |
6dfc0665 DH |
340 | config FRAME_POINTER |
341 | bool "Compile the kernel with frame pointers" | |
342 | depends on DEBUG_KERNEL && \ | |
343 | (CRIS || M68K || FRV || UML || \ | |
344 | AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \ | |
345 | ARCH_WANT_FRAME_POINTERS | |
346 | default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS | |
a304e1b8 | 347 | help |
6dfc0665 DH |
348 | If you say Y here the resulting kernel image will be slightly |
349 | larger and slower, but it gives very useful debugging information | |
350 | in case of kernel bugs. (precise oopses/stacktraces/warnings) | |
a304e1b8 | 351 | |
6dfc0665 DH |
352 | config DEBUG_FORCE_WEAK_PER_CPU |
353 | bool "Force weak per-cpu definitions" | |
354 | depends on DEBUG_KERNEL | |
8446f1d3 | 355 | help |
6dfc0665 DH |
356 | s390 and alpha require percpu variables in modules to be |
357 | defined weak to work around addressing range issue which | |
358 | puts the following two restrictions on percpu variable | |
359 | definitions. | |
8446f1d3 | 360 | |
6dfc0665 DH |
361 | 1. percpu symbols must be unique whether static or not |
362 | 2. percpu variables can't be defined inside a function | |
8446f1d3 | 363 | |
6dfc0665 DH |
364 | To ensure that generic code follows the above rules, this |
365 | option forces all percpu variables to be defined as weak. | |
5f329089 | 366 | |
6dfc0665 | 367 | endmenu # "Compiler options" |
8446f1d3 | 368 | |
6dfc0665 DH |
369 | config MAGIC_SYSRQ |
370 | bool "Magic SysRq key" | |
371 | depends on !UML | |
372 | help | |
373 | If you say Y here, you will have some control over the system even | |
374 | if the system crashes for example during kernel debugging (e.g., you | |
375 | will be able to flush the buffer cache to disk, reboot the system | |
376 | immediately or dump some status information). This is accomplished | |
377 | by pressing various keys while holding SysRq (Alt+PrintScreen). It | |
378 | also works on a serial console (on PC hardware at least), if you | |
379 | send a BREAK and then within 5 seconds a command keypress. The | |
380 | keys are documented in <file:Documentation/sysrq.txt>. Don't say Y | |
381 | unless you really know what this hack does. | |
8446f1d3 | 382 | |
8eaede49 BH |
383 | config MAGIC_SYSRQ_DEFAULT_ENABLE |
384 | hex "Enable magic SysRq key functions by default" | |
385 | depends on MAGIC_SYSRQ | |
386 | default 0x1 | |
387 | help | |
388 | Specifies which SysRq key functions are enabled by default. | |
389 | This may be set to 1 or 0 to enable or disable them all, or | |
390 | to a bitmask as described in Documentation/sysrq.txt. | |
391 | ||
f346f4b3 AB |
392 | config DEBUG_KERNEL |
393 | bool "Kernel debugging" | |
fef2c9bc | 394 | help |
f346f4b3 AB |
395 | Say Y here if you are developing drivers or trying to debug and |
396 | identify kernel problems. | |
fef2c9bc | 397 | |
0610c8a8 | 398 | menu "Memory Debugging" |
fef2c9bc | 399 | |
0610c8a8 | 400 | source mm/Kconfig.debug |
fef2c9bc | 401 | |
0610c8a8 DH |
402 | config DEBUG_OBJECTS |
403 | bool "Debug object operations" | |
404 | depends on DEBUG_KERNEL | |
9c44bc03 | 405 | help |
0610c8a8 DH |
406 | If you say Y here, additional code will be inserted into the |
407 | kernel to track the life time of various objects and validate | |
408 | the operations on those objects. | |
9c44bc03 | 409 | |
0610c8a8 DH |
410 | config DEBUG_OBJECTS_SELFTEST |
411 | bool "Debug objects selftest" | |
412 | depends on DEBUG_OBJECTS | |
413 | help | |
414 | This enables the selftest of the object debug code. | |
9c44bc03 | 415 | |
0610c8a8 DH |
416 | config DEBUG_OBJECTS_FREE |
417 | bool "Debug objects in freed memory" | |
418 | depends on DEBUG_OBJECTS | |
419 | help | |
420 | This enables checks whether a k/v free operation frees an area | |
421 | which contains an object which has not been deactivated | |
422 | properly. This can make kmalloc/kfree-intensive workloads | |
423 | much slower. | |
3ac7fe5a | 424 | |
c6f3a97f TG |
425 | config DEBUG_OBJECTS_TIMERS |
426 | bool "Debug timer objects" | |
427 | depends on DEBUG_OBJECTS | |
428 | help | |
429 | If you say Y here, additional code will be inserted into the | |
430 | timer routines to track the life time of timer objects and | |
431 | validate the timer operations. | |
432 | ||
dc186ad7 TG |
433 | config DEBUG_OBJECTS_WORK |
434 | bool "Debug work objects" | |
435 | depends on DEBUG_OBJECTS | |
436 | help | |
437 | If you say Y here, additional code will be inserted into the | |
438 | work queue routines to track the life time of work objects and | |
439 | validate the work operations. | |
440 | ||
551d55a9 MD |
441 | config DEBUG_OBJECTS_RCU_HEAD |
442 | bool "Debug RCU callbacks objects" | |
fc2ecf7e | 443 | depends on DEBUG_OBJECTS |
551d55a9 MD |
444 | help |
445 | Enable this to turn on debugging of RCU list heads (call_rcu() usage). | |
446 | ||
e2852ae8 TH |
447 | config DEBUG_OBJECTS_PERCPU_COUNTER |
448 | bool "Debug percpu counter objects" | |
449 | depends on DEBUG_OBJECTS | |
450 | help | |
451 | If you say Y here, additional code will be inserted into the | |
452 | percpu counter routines to track the life time of percpu counter | |
453 | objects and validate the percpu counter operations. | |
454 | ||
3ae70205 IM |
455 | config DEBUG_OBJECTS_ENABLE_DEFAULT |
456 | int "debug_objects bootup default value (0-1)" | |
457 | range 0 1 | |
458 | default "1" | |
459 | depends on DEBUG_OBJECTS | |
460 | help | |
461 | Debug objects boot parameter default value | |
462 | ||
1da177e4 | 463 | config DEBUG_SLAB |
4a2f0acf | 464 | bool "Debug slab memory allocations" |
7d46d9e6 | 465 | depends on DEBUG_KERNEL && SLAB && !KMEMCHECK |
1da177e4 LT |
466 | help |
467 | Say Y here to have the kernel do limited verification on memory | |
468 | allocation as well as poisoning memory on free to catch use of freed | |
469 | memory. This can make kmalloc/kfree-intensive workloads much slower. | |
470 | ||
871751e2 AV |
471 | config DEBUG_SLAB_LEAK |
472 | bool "Memory leak debugging" | |
473 | depends on DEBUG_SLAB | |
474 | ||
f0630fff CL |
475 | config SLUB_DEBUG_ON |
476 | bool "SLUB debugging on by default" | |
7d46d9e6 | 477 | depends on SLUB && SLUB_DEBUG && !KMEMCHECK |
f0630fff CL |
478 | default n |
479 | help | |
480 | Boot with debugging on by default. SLUB boots by default with | |
481 | the runtime debug capabilities switched off. Enabling this is | |
482 | equivalent to specifying the "slub_debug" parameter on boot. | |
483 | There is no support for more fine grained debug control like | |
484 | possible with slub_debug=xxx. SLUB debugging may be switched | |
485 | off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying | |
486 | "slub_debug=-". | |
487 | ||
8ff12cfc CL |
488 | config SLUB_STATS |
489 | default n | |
490 | bool "Enable SLUB performance statistics" | |
ab4d5ed5 | 491 | depends on SLUB && SYSFS |
8ff12cfc CL |
492 | help |
493 | SLUB statistics are useful to debug SLUBs allocation behavior in | |
494 | order find ways to optimize the allocator. This should never be | |
495 | enabled for production use since keeping statistics slows down | |
496 | the allocator by a few percentage points. The slabinfo command | |
497 | supports the determination of the most active slabs to figure | |
498 | out which slabs are relevant to a particular load. | |
499 | Try running: slabinfo -DA | |
500 | ||
b69ec42b CM |
501 | config HAVE_DEBUG_KMEMLEAK |
502 | bool | |
503 | ||
3bba00d7 CM |
504 | config DEBUG_KMEMLEAK |
505 | bool "Kernel memory leak detector" | |
525c1f92 | 506 | depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK |
79e0d9bd | 507 | select DEBUG_FS |
3bba00d7 CM |
508 | select STACKTRACE if STACKTRACE_SUPPORT |
509 | select KALLSYMS | |
b60e26a2 | 510 | select CRC32 |
3bba00d7 CM |
511 | help |
512 | Say Y here if you want to enable the memory leak | |
513 | detector. The memory allocation/freeing is traced in a way | |
514 | similar to the Boehm's conservative garbage collector, the | |
515 | difference being that the orphan objects are not freed but | |
516 | only shown in /sys/kernel/debug/kmemleak. Enabling this | |
517 | feature will introduce an overhead to memory | |
518 | allocations. See Documentation/kmemleak.txt for more | |
519 | details. | |
520 | ||
0610c8a8 DH |
521 | Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances |
522 | of finding leaks due to the slab objects poisoning. | |
523 | ||
524 | In order to access the kmemleak file, debugfs needs to be | |
525 | mounted (usually at /sys/kernel/debug). | |
526 | ||
527 | config DEBUG_KMEMLEAK_EARLY_LOG_SIZE | |
528 | int "Maximum kmemleak early log entries" | |
529 | depends on DEBUG_KMEMLEAK | |
530 | range 200 40000 | |
531 | default 400 | |
532 | help | |
533 | Kmemleak must track all the memory allocations to avoid | |
534 | reporting false positives. Since memory may be allocated or | |
535 | freed before kmemleak is initialised, an early log buffer is | |
536 | used to store these actions. If kmemleak reports "early log | |
537 | buffer exceeded", please increase this value. | |
538 | ||
539 | config DEBUG_KMEMLEAK_TEST | |
540 | tristate "Simple test for the kernel memory leak detector" | |
541 | depends on DEBUG_KMEMLEAK && m | |
542 | help | |
543 | This option enables a module that explicitly leaks memory. | |
544 | ||
545 | If unsure, say N. | |
546 | ||
547 | config DEBUG_KMEMLEAK_DEFAULT_OFF | |
548 | bool "Default kmemleak to off" | |
549 | depends on DEBUG_KMEMLEAK | |
550 | help | |
551 | Say Y here to disable kmemleak by default. It can then be enabled | |
552 | on the command line via kmemleak=on. | |
553 | ||
554 | config DEBUG_STACK_USAGE | |
555 | bool "Stack utilization instrumentation" | |
556 | depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG | |
557 | help | |
558 | Enables the display of the minimum amount of free stack which each | |
559 | task has ever had available in the sysrq-T and sysrq-P debug output. | |
560 | ||
561 | This option will slow down process creation somewhat. | |
562 | ||
563 | config DEBUG_VM | |
564 | bool "Debug VM" | |
565 | depends on DEBUG_KERNEL | |
566 | help | |
567 | Enable this to turn on extended checks in the virtual-memory system | |
568 | that may impact performance. | |
569 | ||
570 | If unsure, say N. | |
571 | ||
4f115147 DB |
572 | config DEBUG_VM_VMACACHE |
573 | bool "Debug VMA caching" | |
574 | depends on DEBUG_VM | |
575 | help | |
576 | Enable this to turn on VMA caching debug information. Doing so | |
577 | can cause significant overhead, so only enable it in non-production | |
578 | environments. | |
579 | ||
580 | If unsure, say N. | |
581 | ||
0610c8a8 DH |
582 | config DEBUG_VM_RB |
583 | bool "Debug VM red-black trees" | |
584 | depends on DEBUG_VM | |
585 | help | |
a663dad6 | 586 | Enable VM red-black tree debugging information and extra validations. |
0610c8a8 DH |
587 | |
588 | If unsure, say N. | |
589 | ||
590 | config DEBUG_VIRTUAL | |
591 | bool "Debug VM translations" | |
592 | depends on DEBUG_KERNEL && X86 | |
593 | help | |
594 | Enable some costly sanity checks in virtual to page code. This can | |
595 | catch mistakes with virt_to_page() and friends. | |
596 | ||
597 | If unsure, say N. | |
598 | ||
599 | config DEBUG_NOMMU_REGIONS | |
600 | bool "Debug the global anon/private NOMMU mapping region tree" | |
601 | depends on DEBUG_KERNEL && !MMU | |
602 | help | |
603 | This option causes the global tree of anonymous and private mapping | |
604 | regions to be regularly checked for invalid topology. | |
605 | ||
606 | config DEBUG_MEMORY_INIT | |
607 | bool "Debug memory initialisation" if EXPERT | |
608 | default !EXPERT | |
609 | help | |
610 | Enable this for additional checks during memory initialisation. | |
611 | The sanity checks verify aspects of the VM such as the memory model | |
612 | and other information provided by the architecture. Verbose | |
613 | information will be printed at KERN_DEBUG loglevel depending | |
614 | on the mminit_loglevel= command-line option. | |
615 | ||
616 | If unsure, say Y | |
617 | ||
618 | config MEMORY_NOTIFIER_ERROR_INJECT | |
619 | tristate "Memory hotplug notifier error injection module" | |
620 | depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION | |
621 | help | |
622 | This option provides the ability to inject artificial errors to | |
623 | memory hotplug notifier chain callbacks. It is controlled through | |
624 | debugfs interface under /sys/kernel/debug/notifier-error-inject/memory | |
625 | ||
626 | If the notifier call chain should be failed with some events | |
627 | notified, write the error code to "actions/<notifier event>/error". | |
628 | ||
629 | Example: Inject memory hotplug offline error (-12 == -ENOMEM) | |
630 | ||
631 | # cd /sys/kernel/debug/notifier-error-inject/memory | |
632 | # echo -12 > actions/MEM_GOING_OFFLINE/error | |
633 | # echo offline > /sys/devices/system/memory/memoryXXX/state | |
634 | bash: echo: write error: Cannot allocate memory | |
635 | ||
636 | To compile this code as a module, choose M here: the module will | |
637 | be called memory-notifier-error-inject. | |
638 | ||
639 | If unsure, say N. | |
640 | ||
641 | config DEBUG_PER_CPU_MAPS | |
642 | bool "Debug access to per_cpu maps" | |
643 | depends on DEBUG_KERNEL | |
644 | depends on SMP | |
645 | help | |
646 | Say Y to verify that the per_cpu map being accessed has | |
647 | been set up. This adds a fair amount of code to kernel memory | |
648 | and decreases performance. | |
649 | ||
650 | Say N if unsure. | |
651 | ||
652 | config DEBUG_HIGHMEM | |
653 | bool "Highmem debugging" | |
654 | depends on DEBUG_KERNEL && HIGHMEM | |
655 | help | |
b1357c9f GU |
656 | This option enables additional error checking for high memory |
657 | systems. Disable for production systems. | |
0610c8a8 DH |
658 | |
659 | config HAVE_DEBUG_STACKOVERFLOW | |
660 | bool | |
661 | ||
662 | config DEBUG_STACKOVERFLOW | |
663 | bool "Check for stack overflows" | |
664 | depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW | |
665 | ---help--- | |
666 | Say Y here if you want to check for overflows of kernel, IRQ | |
edb0ec07 | 667 | and exception stacks (if your architecture uses them). This |
0610c8a8 DH |
668 | option will show detailed messages if free stack space drops |
669 | below a certain limit. | |
670 | ||
671 | These kinds of bugs usually occur when call-chains in the | |
672 | kernel get too deep, especially when interrupts are | |
673 | involved. | |
674 | ||
675 | Use this in cases where you see apparently random memory | |
676 | corruption, especially if it appears in 'struct thread_info' | |
677 | ||
678 | If in doubt, say "N". | |
679 | ||
680 | source "lib/Kconfig.kmemcheck" | |
681 | ||
0b24becc AR |
682 | source "lib/Kconfig.kasan" |
683 | ||
0610c8a8 DH |
684 | endmenu # "Memory Debugging" |
685 | ||
9b83f370 DV |
686 | config ARCH_HAS_KCOV |
687 | bool | |
688 | help | |
689 | KCOV does not have any arch-specific code, but currently it is enabled | |
690 | only for x86_64. KCOV requires testing on other archs, and most likely | |
691 | disabling of instrumentation for some early boot code. | |
692 | ||
693 | config KCOV | |
694 | bool "Code coverage for fuzzing" | |
695 | depends on ARCH_HAS_KCOV | |
696 | select DEBUG_FS | |
697 | help | |
698 | KCOV exposes kernel code coverage information in a form suitable | |
699 | for coverage-guided fuzzing (randomized testing). | |
700 | ||
701 | If RANDOMIZE_BASE is enabled, PC values will not be stable across | |
702 | different machines and across reboots. If you need stable PC values, | |
703 | disable RANDOMIZE_BASE. | |
704 | ||
705 | For more details, see Documentation/kcov.txt. | |
706 | ||
a304e1b8 DW |
707 | config DEBUG_SHIRQ |
708 | bool "Debug shared IRQ handlers" | |
0244ad00 | 709 | depends on DEBUG_KERNEL |
a304e1b8 DW |
710 | help |
711 | Enable this to generate a spurious interrupt as soon as a shared | |
712 | interrupt handler is registered, and just before one is deregistered. | |
713 | Drivers ought to be able to handle interrupts coming in at those | |
714 | points; some don't and need to be caught. | |
715 | ||
92aef8fb DH |
716 | menu "Debug Lockups and Hangs" |
717 | ||
58687acb DZ |
718 | config LOCKUP_DETECTOR |
719 | bool "Detect Hard and Soft Lockups" | |
dea20a3f | 720 | depends on DEBUG_KERNEL && !S390 |
8446f1d3 | 721 | help |
58687acb DZ |
722 | Say Y here to enable the kernel to act as a watchdog to detect |
723 | hard and soft lockups. | |
724 | ||
725 | Softlockups are bugs that cause the kernel to loop in kernel | |
5f329089 | 726 | mode for more than 20 seconds, without giving other tasks a |
58687acb DZ |
727 | chance to run. The current stack trace is displayed upon |
728 | detection and the system will stay locked up. | |
8446f1d3 | 729 | |
58687acb | 730 | Hardlockups are bugs that cause the CPU to loop in kernel mode |
5f329089 | 731 | for more than 10 seconds, without letting other interrupts have a |
58687acb DZ |
732 | chance to run. The current stack trace is displayed upon detection |
733 | and the system will stay locked up. | |
8446f1d3 | 734 | |
58687acb | 735 | The overhead should be minimal. A periodic hrtimer runs to |
5f329089 FLVC |
736 | generate interrupts and kick the watchdog task every 4 seconds. |
737 | An NMI is generated every 10 seconds or so to check for hardlockups. | |
55d35d82 CC |
738 | If NMIs are not available on the platform, every 12 seconds the |
739 | hrtimer interrupt on one cpu will be used to check for hardlockups | |
740 | on the next cpu. | |
5f329089 FLVC |
741 | |
742 | The frequency of hrtimer and NMI events and the soft and hard lockup | |
743 | thresholds can be controlled through the sysctl watchdog_thresh. | |
8446f1d3 | 744 | |
55d35d82 | 745 | config HARDLOCKUP_DETECTOR_NMI |
8f1f66ed JB |
746 | def_bool y |
747 | depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG | |
748 | depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI | |
8446f1d3 | 749 | |
55d35d82 CC |
750 | config HARDLOCKUP_DETECTOR_OTHER_CPU |
751 | def_bool y | |
752 | depends on LOCKUP_DETECTOR && SMP | |
753 | depends on !HARDLOCKUP_DETECTOR_NMI && !HAVE_NMI_WATCHDOG | |
754 | ||
755 | config HARDLOCKUP_DETECTOR | |
756 | def_bool y | |
757 | depends on HARDLOCKUP_DETECTOR_NMI || HARDLOCKUP_DETECTOR_OTHER_CPU | |
758 | ||
fef2c9bc DZ |
759 | config BOOTPARAM_HARDLOCKUP_PANIC |
760 | bool "Panic (Reboot) On Hard Lockups" | |
8f1f66ed | 761 | depends on HARDLOCKUP_DETECTOR |
fef2c9bc DZ |
762 | help |
763 | Say Y here to enable the kernel to panic on "hard lockups", | |
764 | which are bugs that cause the kernel to loop in kernel | |
5f329089 FLVC |
765 | mode with interrupts disabled for more than 10 seconds (configurable |
766 | using the watchdog_thresh sysctl). | |
fef2c9bc DZ |
767 | |
768 | Say N if unsure. | |
769 | ||
770 | config BOOTPARAM_HARDLOCKUP_PANIC_VALUE | |
771 | int | |
8f1f66ed | 772 | depends on HARDLOCKUP_DETECTOR |
fef2c9bc DZ |
773 | range 0 1 |
774 | default 0 if !BOOTPARAM_HARDLOCKUP_PANIC | |
775 | default 1 if BOOTPARAM_HARDLOCKUP_PANIC | |
776 | ||
9c44bc03 IM |
777 | config BOOTPARAM_SOFTLOCKUP_PANIC |
778 | bool "Panic (Reboot) On Soft Lockups" | |
89d7ce2a | 779 | depends on LOCKUP_DETECTOR |
9c44bc03 IM |
780 | help |
781 | Say Y here to enable the kernel to panic on "soft lockups", | |
782 | which are bugs that cause the kernel to loop in kernel | |
5f329089 FLVC |
783 | mode for more than 20 seconds (configurable using the watchdog_thresh |
784 | sysctl), without giving other tasks a chance to run. | |
9c44bc03 IM |
785 | |
786 | The panic can be used in combination with panic_timeout, | |
787 | to cause the system to reboot automatically after a | |
788 | lockup has been detected. This feature is useful for | |
789 | high-availability systems that have uptime guarantees and | |
790 | where a lockup must be resolved ASAP. | |
791 | ||
792 | Say N if unsure. | |
793 | ||
794 | config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE | |
795 | int | |
e16bb1d7 | 796 | depends on LOCKUP_DETECTOR |
9c44bc03 IM |
797 | range 0 1 |
798 | default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC | |
799 | default 1 if BOOTPARAM_SOFTLOCKUP_PANIC | |
800 | ||
e162b39a MSB |
801 | config DETECT_HUNG_TASK |
802 | bool "Detect Hung Tasks" | |
803 | depends on DEBUG_KERNEL | |
8edbb83e | 804 | default LOCKUP_DETECTOR |
e162b39a | 805 | help |
0610c8a8 DH |
806 | Say Y here to enable the kernel to detect "hung tasks", |
807 | which are bugs that cause the task to be stuck in | |
808 | uninterruptible "D" state indefinitiley. | |
1da177e4 | 809 | |
0610c8a8 DH |
810 | When a hung task is detected, the kernel will print the |
811 | current stack trace (which you should report), but the | |
812 | task will stay in uninterruptible state. If lockdep is | |
813 | enabled then all held locks will also be reported. This | |
814 | feature has negligible overhead. | |
871751e2 | 815 | |
0610c8a8 DH |
816 | config DEFAULT_HUNG_TASK_TIMEOUT |
817 | int "Default timeout for hung task detection (in seconds)" | |
818 | depends on DETECT_HUNG_TASK | |
819 | default 120 | |
f0630fff | 820 | help |
0610c8a8 DH |
821 | This option controls the default timeout (in seconds) used |
822 | to determine when a task has become non-responsive and should | |
823 | be considered hung. | |
f0630fff | 824 | |
0610c8a8 DH |
825 | It can be adjusted at runtime via the kernel.hung_task_timeout_secs |
826 | sysctl or by writing a value to | |
827 | /proc/sys/kernel/hung_task_timeout_secs. | |
8ff12cfc | 828 | |
0610c8a8 DH |
829 | A timeout of 0 disables the check. The default is two minutes. |
830 | Keeping the default should be fine in most cases. | |
b69ec42b | 831 | |
0610c8a8 DH |
832 | config BOOTPARAM_HUNG_TASK_PANIC |
833 | bool "Panic (Reboot) On Hung Tasks" | |
834 | depends on DETECT_HUNG_TASK | |
3bba00d7 | 835 | help |
0610c8a8 DH |
836 | Say Y here to enable the kernel to panic on "hung tasks", |
837 | which are bugs that cause the kernel to leave a task stuck | |
838 | in uninterruptible "D" state. | |
3bba00d7 | 839 | |
0610c8a8 DH |
840 | The panic can be used in combination with panic_timeout, |
841 | to cause the system to reboot automatically after a | |
842 | hung task has been detected. This feature is useful for | |
843 | high-availability systems that have uptime guarantees and | |
844 | where a hung tasks must be resolved ASAP. | |
bf96d1e3 | 845 | |
0610c8a8 | 846 | Say N if unsure. |
bf96d1e3 | 847 | |
0610c8a8 DH |
848 | config BOOTPARAM_HUNG_TASK_PANIC_VALUE |
849 | int | |
850 | depends on DETECT_HUNG_TASK | |
851 | range 0 1 | |
852 | default 0 if !BOOTPARAM_HUNG_TASK_PANIC | |
853 | default 1 if BOOTPARAM_HUNG_TASK_PANIC | |
3bba00d7 | 854 | |
92aef8fb DH |
855 | endmenu # "Debug lockups and hangs" |
856 | ||
857 | config PANIC_ON_OOPS | |
858 | bool "Panic on Oops" | |
a9d9058a | 859 | help |
92aef8fb DH |
860 | Say Y here to enable the kernel to panic when it oopses. This |
861 | has the same effect as setting oops=panic on the kernel command | |
862 | line. | |
a9d9058a | 863 | |
92aef8fb DH |
864 | This feature is useful to ensure that the kernel does not do |
865 | anything erroneous after an oops which could result in data | |
866 | corruption or other issues. | |
867 | ||
868 | Say N if unsure. | |
869 | ||
870 | config PANIC_ON_OOPS_VALUE | |
871 | int | |
872 | range 0 1 | |
873 | default 0 if !PANIC_ON_OOPS | |
874 | default 1 if PANIC_ON_OOPS | |
875 | ||
5800dc3c JB |
876 | config PANIC_TIMEOUT |
877 | int "panic timeout" | |
878 | default 0 | |
879 | help | |
880 | Set the timeout value (in seconds) until a reboot occurs when the | |
881 | the kernel panics. If n = 0, then we wait forever. A timeout | |
882 | value n > 0 will wait n seconds before rebooting, while a timeout | |
883 | value n < 0 will reboot immediately. | |
884 | ||
0610c8a8 DH |
885 | config SCHED_DEBUG |
886 | bool "Collect scheduler debugging info" | |
887 | depends on DEBUG_KERNEL && PROC_FS | |
888 | default y | |
0822ee4a | 889 | help |
0610c8a8 DH |
890 | If you say Y here, the /proc/sched_debug file will be provided |
891 | that can help debug the scheduler. The runtime overhead of this | |
892 | option is minimal. | |
0822ee4a | 893 | |
f6db8347 NR |
894 | config SCHED_INFO |
895 | bool | |
896 | default n | |
897 | ||
2a444539 MW |
898 | config PANIC_ON_RT_THROTTLING |
899 | bool "Panic on RT throttling" | |
900 | help | |
901 | Say Y here to enable the kernel to panic when a realtime | |
902 | runqueue is throttled. This may be useful for detecting | |
903 | and debugging RT throttling issues. | |
904 | ||
905 | Say N if unsure. | |
906 | ||
0610c8a8 DH |
907 | config SCHEDSTATS |
908 | bool "Collect scheduler statistics" | |
909 | depends on DEBUG_KERNEL && PROC_FS | |
f6db8347 | 910 | select SCHED_INFO |
0610c8a8 DH |
911 | help |
912 | If you say Y here, additional code will be inserted into the | |
913 | scheduler and related routines to collect statistics about | |
914 | scheduler behavior and provide them in /proc/schedstat. These | |
915 | stats may be useful for both tuning and debugging the scheduler | |
916 | If you aren't debugging the scheduler or trying to tune a specific | |
917 | application, you can say N to avoid the very slight overhead | |
918 | this adds. | |
0822ee4a | 919 | |
0d9e2632 AT |
920 | config SCHED_STACK_END_CHECK |
921 | bool "Detect stack corruption on calls to schedule()" | |
922 | depends on DEBUG_KERNEL | |
923 | default n | |
924 | help | |
925 | This option checks for a stack overrun on calls to schedule(). | |
926 | If the stack end location is found to be over written always panic as | |
927 | the content of the corrupted region can no longer be trusted. | |
928 | This is to ensure no erroneous behaviour occurs which could result in | |
929 | data corruption or a sporadic crash at a later stage once the region | |
930 | is examined. The runtime overhead introduced is minimal. | |
931 | ||
3c17ad19 JS |
932 | config DEBUG_TIMEKEEPING |
933 | bool "Enable extra timekeeping sanity checking" | |
934 | help | |
935 | This option will enable additional timekeeping sanity checks | |
936 | which may be helpful when diagnosing issues where timekeeping | |
937 | problems are suspected. | |
938 | ||
939 | This may include checks in the timekeeping hotpaths, so this | |
940 | option may have a (very small) performance impact to some | |
941 | workloads. | |
942 | ||
943 | If unsure, say N. | |
944 | ||
0610c8a8 DH |
945 | config TIMER_STATS |
946 | bool "Collect kernel timers statistics" | |
947 | depends on DEBUG_KERNEL && PROC_FS | |
ab0155a2 | 948 | help |
0610c8a8 DH |
949 | If you say Y here, additional code will be inserted into the |
950 | timer routines to collect statistics about kernel timers being | |
951 | reprogrammed. The statistics can be read from /proc/timer_stats. | |
952 | The statistics collection is started by writing 1 to /proc/timer_stats, | |
953 | writing 0 stops it. This feature is useful to collect information | |
954 | about timer usage patterns in kernel and userspace. This feature | |
955 | is lightweight if enabled in the kernel config but not activated | |
956 | (it defaults to deactivated on bootup and will only be activated | |
957 | if some application like powertop activates it explicitly). | |
ab0155a2 | 958 | |
1da177e4 LT |
959 | config DEBUG_PREEMPT |
960 | bool "Debug preemptible kernel" | |
01deab98 | 961 | depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT |
1da177e4 LT |
962 | default y |
963 | help | |
964 | If you say Y here then the kernel will use a debug variant of the | |
965 | commonly used smp_processor_id() function and will print warnings | |
966 | if kernel code uses it in a preemption-unsafe way. Also, the kernel | |
967 | will detect preemption count underflows. | |
968 | ||
9eade16b DH |
969 | menu "Lock Debugging (spinlocks, mutexes, etc...)" |
970 | ||
e7eebaf6 IM |
971 | config DEBUG_RT_MUTEXES |
972 | bool "RT Mutex debugging, deadlock detection" | |
e7eebaf6 IM |
973 | depends on DEBUG_KERNEL && RT_MUTEXES |
974 | help | |
975 | This allows rt mutex semantics violations and rt mutex related | |
976 | deadlocks (lockups) to be detected and reported automatically. | |
977 | ||
1da177e4 | 978 | config DEBUG_SPINLOCK |
4d9f34ad | 979 | bool "Spinlock and rw-lock debugging: basic checks" |
1da177e4 | 980 | depends on DEBUG_KERNEL |
e335e3eb | 981 | select UNINLINE_SPIN_UNLOCK |
1da177e4 LT |
982 | help |
983 | Say Y here and build SMP to catch missing spinlock initialization | |
984 | and certain other kinds of spinlock errors commonly made. This is | |
985 | best used in conjunction with the NMI watchdog so that spinlock | |
986 | deadlocks are also debuggable. | |
987 | ||
4d9f34ad IM |
988 | config DEBUG_MUTEXES |
989 | bool "Mutex debugging: basic checks" | |
990 | depends on DEBUG_KERNEL | |
991 | help | |
992 | This feature allows mutex semantics violations to be detected and | |
993 | reported. | |
994 | ||
23010027 DV |
995 | config DEBUG_WW_MUTEX_SLOWPATH |
996 | bool "Wait/wound mutex debugging: Slowpath testing" | |
997 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT | |
998 | select DEBUG_LOCK_ALLOC | |
999 | select DEBUG_SPINLOCK | |
1000 | select DEBUG_MUTEXES | |
1001 | help | |
1002 | This feature enables slowpath testing for w/w mutex users by | |
1003 | injecting additional -EDEADLK wound/backoff cases. Together with | |
1004 | the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this | |
1005 | will test all possible w/w mutex interface abuse with the | |
1006 | exception of simply not acquiring all the required locks. | |
4d692373 RC |
1007 | Note that this feature can introduce significant overhead, so |
1008 | it really should not be enabled in a production or distro kernel, | |
1009 | even a debug kernel. If you are a driver writer, enable it. If | |
1010 | you are a distro, do not. | |
23010027 | 1011 | |
4d9f34ad IM |
1012 | config DEBUG_LOCK_ALLOC |
1013 | bool "Lock debugging: detect incorrect freeing of live locks" | |
517e7aa5 | 1014 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
1015 | select DEBUG_SPINLOCK |
1016 | select DEBUG_MUTEXES | |
4d9f34ad IM |
1017 | select LOCKDEP |
1018 | help | |
1019 | This feature will check whether any held lock (spinlock, rwlock, | |
1020 | mutex or rwsem) is incorrectly freed by the kernel, via any of the | |
1021 | memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), | |
1022 | vfree(), etc.), whether a live lock is incorrectly reinitialized via | |
1023 | spin_lock_init()/mutex_init()/etc., or whether there is any lock | |
1024 | held during task exit. | |
1025 | ||
1026 | config PROVE_LOCKING | |
1027 | bool "Lock debugging: prove locking correctness" | |
517e7aa5 | 1028 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
1029 | select LOCKDEP |
1030 | select DEBUG_SPINLOCK | |
1031 | select DEBUG_MUTEXES | |
4d9f34ad | 1032 | select DEBUG_LOCK_ALLOC |
46b93b74 | 1033 | select TRACE_IRQFLAGS |
4d9f34ad IM |
1034 | default n |
1035 | help | |
1036 | This feature enables the kernel to prove that all locking | |
1037 | that occurs in the kernel runtime is mathematically | |
1038 | correct: that under no circumstance could an arbitrary (and | |
1039 | not yet triggered) combination of observed locking | |
1040 | sequences (on an arbitrary number of CPUs, running an | |
1041 | arbitrary number of tasks and interrupt contexts) cause a | |
1042 | deadlock. | |
1043 | ||
1044 | In short, this feature enables the kernel to report locking | |
1045 | related deadlocks before they actually occur. | |
1046 | ||
1047 | The proof does not depend on how hard and complex a | |
1048 | deadlock scenario would be to trigger: how many | |
1049 | participant CPUs, tasks and irq-contexts would be needed | |
1050 | for it to trigger. The proof also does not depend on | |
1051 | timing: if a race and a resulting deadlock is possible | |
1052 | theoretically (no matter how unlikely the race scenario | |
1053 | is), it will be proven so and will immediately be | |
1054 | reported by the kernel (once the event is observed that | |
1055 | makes the deadlock theoretically possible). | |
1056 | ||
1057 | If a deadlock is impossible (i.e. the locking rules, as | |
1058 | observed by the kernel, are mathematically correct), the | |
1059 | kernel reports nothing. | |
1060 | ||
1061 | NOTE: this feature can also be enabled for rwlocks, mutexes | |
1062 | and rwsems - in which case all dependencies between these | |
1063 | different locking variants are observed and mapped too, and | |
1064 | the proof of observed correctness is also maintained for an | |
1065 | arbitrary combination of these separate locking variants. | |
1066 | ||
214e0aed | 1067 | For more details, see Documentation/locking/lockdep-design.txt. |
4d9f34ad IM |
1068 | |
1069 | config LOCKDEP | |
1070 | bool | |
517e7aa5 | 1071 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad | 1072 | select STACKTRACE |
df2e1ef6 | 1073 | select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC && !SCORE |
4d9f34ad IM |
1074 | select KALLSYMS |
1075 | select KALLSYMS_ALL | |
1076 | ||
f20786ff | 1077 | config LOCK_STAT |
fdfb870f | 1078 | bool "Lock usage statistics" |
f20786ff PZ |
1079 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
1080 | select LOCKDEP | |
1081 | select DEBUG_SPINLOCK | |
1082 | select DEBUG_MUTEXES | |
1083 | select DEBUG_LOCK_ALLOC | |
1084 | default n | |
1085 | help | |
1086 | This feature enables tracking lock contention points | |
1087 | ||
214e0aed | 1088 | For more details, see Documentation/locking/lockstat.txt |
a560aa48 | 1089 | |
dd8b1cf6 FW |
1090 | This also enables lock events required by "perf lock", |
1091 | subcommand of perf. | |
1092 | If you want to use "perf lock", you also need to turn on | |
1093 | CONFIG_EVENT_TRACING. | |
84c6f88f HM |
1094 | |
1095 | CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. | |
dd8b1cf6 | 1096 | (CONFIG_LOCKDEP defines "acquire" and "release" events.) |
84c6f88f | 1097 | |
4d9f34ad IM |
1098 | config DEBUG_LOCKDEP |
1099 | bool "Lock dependency engine debugging" | |
517e7aa5 | 1100 | depends on DEBUG_KERNEL && LOCKDEP |
4d9f34ad IM |
1101 | help |
1102 | If you say Y here, the lock dependency engine will do | |
1103 | additional runtime checks to debug itself, at the price | |
1104 | of more runtime overhead. | |
1105 | ||
d902db1e FW |
1106 | config DEBUG_ATOMIC_SLEEP |
1107 | bool "Sleep inside atomic section checking" | |
e8f7c70f | 1108 | select PREEMPT_COUNT |
1da177e4 LT |
1109 | depends on DEBUG_KERNEL |
1110 | help | |
1111 | If you say Y here, various routines which may sleep will become very | |
d902db1e FW |
1112 | noisy if they are called inside atomic sections: when a spinlock is |
1113 | held, inside an rcu read side critical section, inside preempt disabled | |
1114 | sections, inside an interrupt, etc... | |
1da177e4 | 1115 | |
cae2ed9a IM |
1116 | config DEBUG_LOCKING_API_SELFTESTS |
1117 | bool "Locking API boot-time self-tests" | |
1118 | depends on DEBUG_KERNEL | |
1119 | help | |
1120 | Say Y here if you want the kernel to run a short self-test during | |
1121 | bootup. The self-test checks whether common types of locking bugs | |
1122 | are detected by debugging mechanisms or not. (if you disable | |
1123 | lock debugging then those bugs wont be detected of course.) | |
1124 | The following locking APIs are covered: spinlocks, rwlocks, | |
1125 | mutexes and rwsems. | |
1126 | ||
0af3fe1e PM |
1127 | config LOCK_TORTURE_TEST |
1128 | tristate "torture tests for locking" | |
1129 | depends on DEBUG_KERNEL | |
1130 | select TORTURE_TEST | |
1131 | default n | |
1132 | help | |
1133 | This option provides a kernel module that runs torture tests | |
1134 | on kernel locking primitives. The kernel module may be built | |
1135 | after the fact on the running kernel to be tested, if desired. | |
1136 | ||
1137 | Say Y here if you want kernel locking-primitive torture tests | |
1138 | to be built into the kernel. | |
1139 | Say M if you want these torture tests to build as a module. | |
1140 | Say N if you are unsure. | |
1141 | ||
9eade16b | 1142 | endmenu # lock debugging |
8637c099 | 1143 | |
9eade16b DH |
1144 | config TRACE_IRQFLAGS |
1145 | bool | |
5ca43f6c | 1146 | help |
9eade16b DH |
1147 | Enables hooks to interrupt enabling and disabling for |
1148 | either tracing or lock debugging. | |
5ca43f6c | 1149 | |
8637c099 | 1150 | config STACKTRACE |
0c38e1fe | 1151 | bool "Stack backtrace support" |
8637c099 | 1152 | depends on STACKTRACE_SUPPORT |
0c38e1fe DJ |
1153 | help |
1154 | This option causes the kernel to create a /proc/pid/stack for | |
1155 | every process, showing its current stack trace. | |
1156 | It is also used by various kernel debugging features that require | |
1157 | stack trace generation. | |
5ca43f6c | 1158 | |
1da177e4 LT |
1159 | config DEBUG_KOBJECT |
1160 | bool "kobject debugging" | |
1161 | depends on DEBUG_KERNEL | |
1162 | help | |
1163 | If you say Y here, some extra kobject debugging messages will be sent | |
1164 | to the syslog. | |
1165 | ||
c817a67e RK |
1166 | config DEBUG_KOBJECT_RELEASE |
1167 | bool "kobject release debugging" | |
2a999aa0 | 1168 | depends on DEBUG_OBJECTS_TIMERS |
c817a67e RK |
1169 | help |
1170 | kobjects are reference counted objects. This means that their | |
1171 | last reference count put is not predictable, and the kobject can | |
1172 | live on past the point at which a driver decides to drop it's | |
1173 | initial reference to the kobject gained on allocation. An | |
1174 | example of this would be a struct device which has just been | |
1175 | unregistered. | |
1176 | ||
1177 | However, some buggy drivers assume that after such an operation, | |
1178 | the memory backing the kobject can be immediately freed. This | |
1179 | goes completely against the principles of a refcounted object. | |
1180 | ||
1181 | If you say Y here, the kernel will delay the release of kobjects | |
1182 | on the last reference count to improve the visibility of this | |
1183 | kind of kobject release bug. | |
1184 | ||
9b2a60c4 CM |
1185 | config HAVE_DEBUG_BUGVERBOSE |
1186 | bool | |
1187 | ||
1da177e4 | 1188 | config DEBUG_BUGVERBOSE |
6a108a14 | 1189 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT |
9b2a60c4 | 1190 | depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE) |
8420e7ef | 1191 | default y |
1da177e4 LT |
1192 | help |
1193 | Say Y here to make BUG() panics output the file name and line number | |
1194 | of the BUG call as well as the EIP and oops trace. This aids | |
1195 | debugging but costs about 70-100K of memory. | |
1196 | ||
199a9afc DJ |
1197 | config DEBUG_LIST |
1198 | bool "Debug linked list manipulation" | |
1199 | depends on DEBUG_KERNEL | |
1200 | help | |
1201 | Enable this to turn on extended checks in the linked-list | |
1202 | walking routines. | |
1203 | ||
1204 | If unsure, say N. | |
1205 | ||
b8cfff68 DS |
1206 | config DEBUG_PI_LIST |
1207 | bool "Debug priority linked list manipulation" | |
1208 | depends on DEBUG_KERNEL | |
1209 | help | |
1210 | Enable this to turn on extended checks in the priority-ordered | |
1211 | linked-list (plist) walking routines. This checks the entire | |
1212 | list multiple times during each manipulation. | |
1213 | ||
1214 | If unsure, say N. | |
1215 | ||
d6ec0842 JA |
1216 | config DEBUG_SG |
1217 | bool "Debug SG table operations" | |
1218 | depends on DEBUG_KERNEL | |
1219 | help | |
1220 | Enable this to turn on checks on scatter-gather tables. This can | |
1221 | help find problems with drivers that do not properly initialize | |
1222 | their sg tables. | |
1223 | ||
1224 | If unsure, say N. | |
1225 | ||
1b2439db AV |
1226 | config DEBUG_NOTIFIERS |
1227 | bool "Debug notifier call chains" | |
1228 | depends on DEBUG_KERNEL | |
1229 | help | |
1230 | Enable this to turn on sanity checking for notifier call chains. | |
1231 | This is most useful for kernel developers to make sure that | |
1232 | modules properly unregister themselves from notifier chains. | |
1233 | This is a relatively cheap check but if you care about maximum | |
1234 | performance, say N. | |
1235 | ||
e0e81739 DH |
1236 | config DEBUG_CREDENTIALS |
1237 | bool "Debug credential management" | |
1238 | depends on DEBUG_KERNEL | |
1239 | help | |
1240 | Enable this to turn on some debug checking for credential | |
1241 | management. The additional code keeps track of the number of | |
1242 | pointers from task_structs to any given cred struct, and checks to | |
1243 | see that this number never exceeds the usage count of the cred | |
1244 | struct. | |
1245 | ||
1246 | Furthermore, if SELinux is enabled, this also checks that the | |
1247 | security pointer in the cred struct is never seen to be invalid. | |
1248 | ||
1249 | If unsure, say N. | |
1250 | ||
2f03e3ca DH |
1251 | menu "RCU Debugging" |
1252 | ||
1253 | config PROVE_RCU | |
9bae6592 | 1254 | def_bool PROVE_LOCKING |
2f03e3ca DH |
1255 | |
1256 | config PROVE_RCU_REPEATEDLY | |
1257 | bool "RCU debugging: don't disable PROVE_RCU on first splat" | |
1258 | depends on PROVE_RCU | |
1259 | default n | |
1260 | help | |
1261 | By itself, PROVE_RCU will disable checking upon issuing the | |
1262 | first warning (or "splat"). This feature prevents such | |
1263 | disabling, allowing multiple RCU-lockdep warnings to be printed | |
1264 | on a single reboot. | |
1265 | ||
1266 | Say Y to allow multiple RCU-lockdep warnings per boot. | |
1267 | ||
1268 | Say N if you are unsure. | |
1269 | ||
2f03e3ca DH |
1270 | config SPARSE_RCU_POINTER |
1271 | bool "RCU debugging: sparse-based checks for pointer usage" | |
1272 | default n | |
1273 | help | |
1274 | This feature enables the __rcu sparse annotation for | |
1275 | RCU-protected pointers. This annotation will cause sparse | |
1276 | to flag any non-RCU used of annotated pointers. This can be | |
1277 | helpful when debugging RCU usage. Please note that this feature | |
1278 | is not intended to enforce code cleanliness; it is instead merely | |
1279 | a debugging aid. | |
1280 | ||
1281 | Say Y to make sparse flag questionable use of RCU-protected pointers | |
1282 | ||
1283 | Say N if you are unsure. | |
1284 | ||
51b1130e PM |
1285 | config TORTURE_TEST |
1286 | tristate | |
1287 | default n | |
1288 | ||
a241ec65 PM |
1289 | config RCU_TORTURE_TEST |
1290 | tristate "torture tests for RCU" | |
1291 | depends on DEBUG_KERNEL | |
51b1130e | 1292 | select TORTURE_TEST |
83fe27ea | 1293 | select SRCU |
82d0f4c0 | 1294 | select TASKS_RCU |
a241ec65 PM |
1295 | default n |
1296 | help | |
1297 | This option provides a kernel module that runs torture tests | |
1298 | on the RCU infrastructure. The kernel module may be built | |
1299 | after the fact on the running kernel to be tested, if desired. | |
1300 | ||
31a72bce PM |
1301 | Say Y here if you want RCU torture tests to be built into |
1302 | the kernel. | |
a241ec65 PM |
1303 | Say M if you want the RCU torture tests to build as a module. |
1304 | Say N if you are unsure. | |
8bb31b9d | 1305 | |
31a72bce PM |
1306 | config RCU_TORTURE_TEST_RUNNABLE |
1307 | bool "torture tests for RCU runnable by default" | |
1308 | depends on RCU_TORTURE_TEST = y | |
1309 | default n | |
1310 | help | |
1311 | This option provides a way to build the RCU torture tests | |
1312 | directly into the kernel without them starting up at boot | |
1313 | time. You can use /proc/sys/kernel/rcutorture_runnable | |
1314 | to manually override this setting. This /proc file is | |
1315 | available only when the RCU torture tests have been built | |
1316 | into the kernel. | |
1317 | ||
1318 | Say Y here if you want the RCU torture tests to start during | |
1319 | boot (you probably don't). | |
1320 | Say N here if you want the RCU torture tests to start only | |
1321 | after being manually enabled via /proc. | |
1322 | ||
0f41c0dd PM |
1323 | config RCU_TORTURE_TEST_SLOW_PREINIT |
1324 | bool "Slow down RCU grace-period pre-initialization to expose races" | |
1325 | depends on RCU_TORTURE_TEST | |
1326 | help | |
1327 | This option delays grace-period pre-initialization (the | |
1328 | propagation of CPU-hotplug changes up the rcu_node combining | |
1329 | tree) for a few jiffies between initializing each pair of | |
1330 | consecutive rcu_node structures. This helps to expose races | |
1331 | involving grace-period pre-initialization, in other words, it | |
1332 | makes your kernel less stable. It can also greatly increase | |
1333 | grace-period latency, especially on systems with large numbers | |
1334 | of CPUs. This is useful when torture-testing RCU, but in | |
1335 | almost no other circumstance. | |
1336 | ||
1337 | Say Y here if you want your system to crash and hang more often. | |
1338 | Say N if you want a sane system. | |
1339 | ||
1340 | config RCU_TORTURE_TEST_SLOW_PREINIT_DELAY | |
1341 | int "How much to slow down RCU grace-period pre-initialization" | |
1342 | range 0 5 | |
1343 | default 3 | |
1344 | depends on RCU_TORTURE_TEST_SLOW_PREINIT | |
1345 | help | |
1346 | This option specifies the number of jiffies to wait between | |
1347 | each rcu_node structure pre-initialization step. | |
1348 | ||
37745d28 PM |
1349 | config RCU_TORTURE_TEST_SLOW_INIT |
1350 | bool "Slow down RCU grace-period initialization to expose races" | |
1351 | depends on RCU_TORTURE_TEST | |
1352 | help | |
0f41c0dd PM |
1353 | This option delays grace-period initialization for a few |
1354 | jiffies between initializing each pair of consecutive | |
37745d28 PM |
1355 | rcu_node structures. This helps to expose races involving |
1356 | grace-period initialization, in other words, it makes your | |
1357 | kernel less stable. It can also greatly increase grace-period | |
1358 | latency, especially on systems with large numbers of CPUs. | |
1359 | This is useful when torture-testing RCU, but in almost no | |
1360 | other circumstance. | |
1361 | ||
1362 | Say Y here if you want your system to crash and hang more often. | |
1363 | Say N if you want a sane system. | |
1364 | ||
1365 | config RCU_TORTURE_TEST_SLOW_INIT_DELAY | |
1366 | int "How much to slow down RCU grace-period initialization" | |
1367 | range 0 5 | |
186bea5d | 1368 | default 3 |
8d7dc928 | 1369 | depends on RCU_TORTURE_TEST_SLOW_INIT |
37745d28 PM |
1370 | help |
1371 | This option specifies the number of jiffies to wait between | |
1372 | each rcu_node structure initialization. | |
1373 | ||
0f41c0dd PM |
1374 | config RCU_TORTURE_TEST_SLOW_CLEANUP |
1375 | bool "Slow down RCU grace-period cleanup to expose races" | |
1376 | depends on RCU_TORTURE_TEST | |
1377 | help | |
1378 | This option delays grace-period cleanup for a few jiffies | |
1379 | between cleaning up each pair of consecutive rcu_node | |
1380 | structures. This helps to expose races involving grace-period | |
1381 | cleanup, in other words, it makes your kernel less stable. | |
1382 | It can also greatly increase grace-period latency, especially | |
1383 | on systems with large numbers of CPUs. This is useful when | |
1384 | torture-testing RCU, but in almost no other circumstance. | |
1385 | ||
1386 | Say Y here if you want your system to crash and hang more often. | |
1387 | Say N if you want a sane system. | |
1388 | ||
1389 | config RCU_TORTURE_TEST_SLOW_CLEANUP_DELAY | |
1390 | int "How much to slow down RCU grace-period cleanup" | |
1391 | range 0 5 | |
1392 | default 3 | |
1393 | depends on RCU_TORTURE_TEST_SLOW_CLEANUP | |
1394 | help | |
1395 | This option specifies the number of jiffies to wait between | |
1396 | each rcu_node structure cleanup operation. | |
1397 | ||
b163760e PM |
1398 | config RCU_CPU_STALL_TIMEOUT |
1399 | int "RCU CPU stall timeout in seconds" | |
6bfc09e2 | 1400 | depends on RCU_STALL_COMMON |
b163760e | 1401 | range 3 300 |
c896054f | 1402 | default 21 |
b163760e PM |
1403 | help |
1404 | If a given RCU grace period extends more than the specified | |
1405 | number of seconds, a CPU stall warning is printed. If the | |
1406 | RCU grace period persists, additional CPU stall warnings are | |
1407 | printed at more widely spaced intervals. | |
1408 | ||
5c8806a0 PM |
1409 | config RCU_TRACE |
1410 | bool "Enable tracing for RCU" | |
6dab2778 | 1411 | depends on DEBUG_KERNEL |
52494535 | 1412 | select TRACE_CLOCK |
6dab2778 | 1413 | help |
5c8806a0 PM |
1414 | This option provides tracing in RCU which presents stats |
1415 | in debugfs for debugging RCU implementation. | |
ad118c54 | 1416 | |
5c8806a0 | 1417 | Say Y here if you want to enable RCU tracing |
6dab2778 AV |
1418 | Say N if you are unsure. |
1419 | ||
1ce46ee5 | 1420 | config RCU_EQS_DEBUG |
eb6d5b0a | 1421 | bool "Provide debugging asserts for adding NO_HZ support to an arch" |
1ce46ee5 PM |
1422 | depends on DEBUG_KERNEL |
1423 | help | |
1424 | This option provides consistency checks in RCU's handling of | |
1425 | NO_HZ. These checks have proven quite helpful in detecting | |
1426 | bugs in arch-specific NO_HZ code. | |
1427 | ||
1428 | Say N here if you need ultimate kernel/user switch latencies | |
1429 | Say Y if you are unsure | |
1430 | ||
2f03e3ca DH |
1431 | endmenu # "RCU Debugging" |
1432 | ||
870d6656 TH |
1433 | config DEBUG_BLOCK_EXT_DEVT |
1434 | bool "Force extended block device numbers and spread them" | |
1435 | depends on DEBUG_KERNEL | |
1436 | depends on BLOCK | |
759f8ca3 | 1437 | default n |
870d6656 | 1438 | help |
0e11e342 TH |
1439 | BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON |
1440 | SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT | |
1441 | YOU ARE DOING. Distros, please enable this and fix whatever | |
1442 | is broken. | |
1443 | ||
870d6656 TH |
1444 | Conventionally, block device numbers are allocated from |
1445 | predetermined contiguous area. However, extended block area | |
1446 | may introduce non-contiguous block device numbers. This | |
1447 | option forces most block device numbers to be allocated from | |
1448 | the extended space and spreads them to discover kernel or | |
1449 | userland code paths which assume predetermined contiguous | |
1450 | device number allocation. | |
1451 | ||
55dc7db7 TH |
1452 | Note that turning on this debug option shuffles all the |
1453 | device numbers for all IDE and SCSI devices including libata | |
1454 | ones, so root partition specified using device number | |
1455 | directly (via rdev or root=MAJ:MIN) won't work anymore. | |
1456 | Textual device names (root=/dev/sdXn) will continue to work. | |
1457 | ||
870d6656 TH |
1458 | Say N if you are unsure. |
1459 | ||
8d438288 AM |
1460 | config NOTIFIER_ERROR_INJECTION |
1461 | tristate "Notifier error injection" | |
1462 | depends on DEBUG_KERNEL | |
1463 | select DEBUG_FS | |
1464 | help | |
e41e85cc | 1465 | This option provides the ability to inject artificial errors to |
8d438288 AM |
1466 | specified notifier chain callbacks. It is useful to test the error |
1467 | handling of notifier call chain failures. | |
1468 | ||
1469 | Say N if unsure. | |
1470 | ||
c9d221f8 AM |
1471 | config CPU_NOTIFIER_ERROR_INJECT |
1472 | tristate "CPU notifier error injection module" | |
f5a9f52e | 1473 | depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION |
c9d221f8 AM |
1474 | help |
1475 | This option provides a kernel module that can be used to test | |
e41e85cc | 1476 | the error handling of the cpu notifiers by injecting artificial |
f5a9f52e AM |
1477 | errors to CPU notifier chain callbacks. It is controlled through |
1478 | debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu | |
1479 | ||
1480 | If the notifier call chain should be failed with some events | |
1481 | notified, write the error code to "actions/<notifier event>/error". | |
1482 | ||
1483 | Example: Inject CPU offline error (-1 == -EPERM) | |
1484 | ||
1485 | # cd /sys/kernel/debug/notifier-error-inject/cpu | |
1486 | # echo -1 > actions/CPU_DOWN_PREPARE/error | |
1487 | # echo 0 > /sys/devices/system/cpu/cpu1/online | |
1488 | bash: echo: write error: Operation not permitted | |
c9d221f8 AM |
1489 | |
1490 | To compile this code as a module, choose M here: the module will | |
1491 | be called cpu-notifier-error-inject. | |
1492 | ||
1493 | If unsure, say N. | |
1494 | ||
048b9c35 AM |
1495 | config PM_NOTIFIER_ERROR_INJECT |
1496 | tristate "PM notifier error injection module" | |
1497 | depends on PM && NOTIFIER_ERROR_INJECTION | |
1498 | default m if PM_DEBUG | |
1499 | help | |
e41e85cc | 1500 | This option provides the ability to inject artificial errors to |
048b9c35 AM |
1501 | PM notifier chain callbacks. It is controlled through debugfs |
1502 | interface /sys/kernel/debug/notifier-error-inject/pm | |
1503 | ||
1504 | If the notifier call chain should be failed with some events | |
1505 | notified, write the error code to "actions/<notifier event>/error". | |
1506 | ||
1507 | Example: Inject PM suspend error (-12 = -ENOMEM) | |
1508 | ||
1509 | # cd /sys/kernel/debug/notifier-error-inject/pm/ | |
1510 | # echo -12 > actions/PM_SUSPEND_PREPARE/error | |
1511 | # echo mem > /sys/power/state | |
1512 | bash: echo: write error: Cannot allocate memory | |
1513 | ||
1514 | To compile this code as a module, choose M here: the module will | |
1515 | be called pm-notifier-error-inject. | |
1516 | ||
1517 | If unsure, say N. | |
1518 | ||
d526e85f BH |
1519 | config OF_RECONFIG_NOTIFIER_ERROR_INJECT |
1520 | tristate "OF reconfig notifier error injection module" | |
1521 | depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION | |
08dfb4dd | 1522 | help |
e41e85cc | 1523 | This option provides the ability to inject artificial errors to |
d526e85f | 1524 | OF reconfig notifier chain callbacks. It is controlled |
08dfb4dd | 1525 | through debugfs interface under |
d526e85f | 1526 | /sys/kernel/debug/notifier-error-inject/OF-reconfig/ |
08dfb4dd AM |
1527 | |
1528 | If the notifier call chain should be failed with some events | |
1529 | notified, write the error code to "actions/<notifier event>/error". | |
1530 | ||
1531 | To compile this code as a module, choose M here: the module will | |
e12a95f4 | 1532 | be called of-reconfig-notifier-error-inject. |
08dfb4dd AM |
1533 | |
1534 | If unsure, say N. | |
1535 | ||
6ff1cb35 | 1536 | config FAULT_INJECTION |
1ab8509a AM |
1537 | bool "Fault-injection framework" |
1538 | depends on DEBUG_KERNEL | |
329409ae AM |
1539 | help |
1540 | Provide fault-injection framework. | |
1541 | For more details, see Documentation/fault-injection/. | |
6ff1cb35 | 1542 | |
8a8b6502 | 1543 | config FAILSLAB |
1ab8509a AM |
1544 | bool "Fault-injection capability for kmalloc" |
1545 | depends on FAULT_INJECTION | |
773ff60e | 1546 | depends on SLAB || SLUB |
8a8b6502 | 1547 | help |
1ab8509a | 1548 | Provide fault-injection capability for kmalloc. |
8a8b6502 | 1549 | |
933e312e AM |
1550 | config FAIL_PAGE_ALLOC |
1551 | bool "Fault-injection capabilitiy for alloc_pages()" | |
1ab8509a | 1552 | depends on FAULT_INJECTION |
933e312e | 1553 | help |
1ab8509a | 1554 | Provide fault-injection capability for alloc_pages(). |
933e312e | 1555 | |
c17bb495 | 1556 | config FAIL_MAKE_REQUEST |
86327d19 | 1557 | bool "Fault-injection capability for disk IO" |
581d4e28 | 1558 | depends on FAULT_INJECTION && BLOCK |
c17bb495 | 1559 | help |
1ab8509a | 1560 | Provide fault-injection capability for disk IO. |
c17bb495 | 1561 | |
581d4e28 | 1562 | config FAIL_IO_TIMEOUT |
f4d01439 | 1563 | bool "Fault-injection capability for faking disk interrupts" |
581d4e28 JA |
1564 | depends on FAULT_INJECTION && BLOCK |
1565 | help | |
1566 | Provide fault-injection capability on end IO handling. This | |
1567 | will make the block layer "forget" an interrupt as configured, | |
1568 | thus exercising the error handling. | |
1569 | ||
1570 | Only works with drivers that use the generic timeout handling, | |
1571 | for others it wont do anything. | |
1572 | ||
1b676f70 PF |
1573 | config FAIL_MMC_REQUEST |
1574 | bool "Fault-injection capability for MMC IO" | |
1575 | select DEBUG_FS | |
1576 | depends on FAULT_INJECTION && MMC | |
1577 | help | |
1578 | Provide fault-injection capability for MMC IO. | |
1579 | This will make the mmc core return data errors. This is | |
1580 | useful to test the error handling in the mmc block device | |
1581 | and to test how the mmc host driver handles retries from | |
1582 | the block device. | |
1583 | ||
ab51fbab DB |
1584 | config FAIL_FUTEX |
1585 | bool "Fault-injection capability for futexes" | |
1586 | select DEBUG_FS | |
1587 | depends on FAULT_INJECTION && FUTEX | |
1588 | help | |
1589 | Provide fault-injection capability for futexes. | |
1590 | ||
6ff1cb35 AM |
1591 | config FAULT_INJECTION_DEBUG_FS |
1592 | bool "Debugfs entries for fault-injection capabilities" | |
1ab8509a | 1593 | depends on FAULT_INJECTION && SYSFS && DEBUG_FS |
6ff1cb35 | 1594 | help |
1ab8509a | 1595 | Enable configuration of fault-injection capabilities via debugfs. |
1df49008 AM |
1596 | |
1597 | config FAULT_INJECTION_STACKTRACE_FILTER | |
1598 | bool "stacktrace filter for fault-injection capabilities" | |
1599 | depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT | |
6d690dca | 1600 | depends on !X86_64 |
1df49008 | 1601 | select STACKTRACE |
df2e1ef6 | 1602 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !SCORE |
1df49008 AM |
1603 | help |
1604 | Provide stacktrace filter for fault-injection capabilities | |
267c4025 | 1605 | |
9745512c AV |
1606 | config LATENCYTOP |
1607 | bool "Latency measuring infrastructure" | |
625fdcaa RD |
1608 | depends on HAVE_LATENCYTOP_SUPPORT |
1609 | depends on DEBUG_KERNEL | |
1610 | depends on STACKTRACE_SUPPORT | |
1611 | depends on PROC_FS | |
cc80ae38 | 1612 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC |
9745512c AV |
1613 | select KALLSYMS |
1614 | select KALLSYMS_ALL | |
1615 | select STACKTRACE | |
1616 | select SCHEDSTATS | |
1617 | select SCHED_DEBUG | |
9745512c AV |
1618 | help |
1619 | Enable this option if you want to use the LatencyTOP tool | |
1620 | to find out which userspace is blocking on what kernel operations. | |
1621 | ||
446f24d1 SB |
1622 | config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS |
1623 | bool | |
1624 | ||
1625 | config DEBUG_STRICT_USER_COPY_CHECKS | |
1626 | bool "Strict user copy size checks" | |
1627 | depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS | |
1628 | depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING | |
1629 | help | |
1630 | Enabling this option turns a certain set of sanity checks for user | |
1631 | copy operations into compile time failures. | |
1632 | ||
1633 | The copy_from_user() etc checks are there to help test if there | |
1634 | are sufficient security checks on the length argument of | |
1635 | the copy operation, by having gcc prove that the argument is | |
1636 | within bounds. | |
1637 | ||
1638 | If unsure, say N. | |
1639 | ||
16444a8a ACM |
1640 | source kernel/trace/Kconfig |
1641 | ||
881c5149 DH |
1642 | menu "Runtime Testing" |
1643 | ||
1644 | config LKDTM | |
1645 | tristate "Linux Kernel Dump Test Tool Module" | |
1646 | depends on DEBUG_FS | |
1647 | depends on BLOCK | |
1648 | default n | |
1649 | help | |
1650 | This module enables testing of the different dumping mechanisms by | |
1651 | inducing system failures at predefined crash points. | |
1652 | If you don't need it: say N | |
1653 | Choose M here to compile this code as a module. The module will be | |
1654 | called lkdtm. | |
1655 | ||
1656 | Documentation on how to use the module can be found in | |
1657 | Documentation/fault-injection/provoke-crashes.txt | |
1658 | ||
1659 | config TEST_LIST_SORT | |
1660 | bool "Linked list sorting test" | |
1661 | depends on DEBUG_KERNEL | |
1662 | help | |
1663 | Enable this to turn on 'list_sort()' function test. This test is | |
1664 | executed only once during system boot, so affects only boot time. | |
1665 | ||
1666 | If unsure, say N. | |
1667 | ||
1668 | config KPROBES_SANITY_TEST | |
1669 | bool "Kprobes sanity tests" | |
1670 | depends on DEBUG_KERNEL | |
1671 | depends on KPROBES | |
1672 | default n | |
1673 | help | |
1674 | This option provides for testing basic kprobes functionality on | |
1675 | boot. A sample kprobe, jprobe and kretprobe are inserted and | |
1676 | verified for functionality. | |
1677 | ||
1678 | Say N if you are unsure. | |
1679 | ||
1680 | config BACKTRACE_SELF_TEST | |
1681 | tristate "Self test for the backtrace code" | |
1682 | depends on DEBUG_KERNEL | |
1683 | default n | |
1684 | help | |
1685 | This option provides a kernel module that can be used to test | |
1686 | the kernel stack backtrace code. This option is not useful | |
1687 | for distributions or general kernels, but only for kernel | |
1688 | developers working on architecture code. | |
1689 | ||
1690 | Note that if you want to also test saved backtraces, you will | |
1691 | have to enable STACKTRACE as well. | |
1692 | ||
1693 | Say N if you are unsure. | |
1694 | ||
910a742d ML |
1695 | config RBTREE_TEST |
1696 | tristate "Red-Black tree test" | |
7c993e11 | 1697 | depends on DEBUG_KERNEL |
910a742d ML |
1698 | help |
1699 | A benchmark measuring the performance of the rbtree library. | |
1700 | Also includes rbtree invariant checks. | |
1701 | ||
fff3fd8a ML |
1702 | config INTERVAL_TREE_TEST |
1703 | tristate "Interval tree test" | |
1704 | depends on m && DEBUG_KERNEL | |
a88cc108 | 1705 | select INTERVAL_TREE |
fff3fd8a ML |
1706 | help |
1707 | A benchmark measuring the performance of the interval tree library | |
1708 | ||
623fd807 GT |
1709 | config PERCPU_TEST |
1710 | tristate "Per cpu operations test" | |
1711 | depends on m && DEBUG_KERNEL | |
1712 | help | |
1713 | Enable this option to build test module which validates per-cpu | |
1714 | operations. | |
1715 | ||
1716 | If unsure, say N. | |
1717 | ||
881c5149 DH |
1718 | config ATOMIC64_SELFTEST |
1719 | bool "Perform an atomic64_t self-test at boot" | |
1720 | help | |
1721 | Enable this option to test the atomic64_t functions at boot. | |
1722 | ||
1723 | If unsure, say N. | |
1724 | ||
1725 | config ASYNC_RAID6_TEST | |
1726 | tristate "Self test for hardware accelerated raid6 recovery" | |
1727 | depends on ASYNC_RAID6_RECOV | |
1728 | select ASYNC_MEMCPY | |
1729 | ---help--- | |
1730 | This is a one-shot self test that permutes through the | |
1731 | recovery of all the possible two disk failure scenarios for a | |
1732 | N-disk array. Recovery is performed with the asynchronous | |
1733 | raid6 recovery routines, and will optionally use an offload | |
1734 | engine if one is available. | |
1735 | ||
1736 | If unsure, say N. | |
1737 | ||
64d1d77a AS |
1738 | config TEST_HEXDUMP |
1739 | tristate "Test functions located in the hexdump module at runtime" | |
1740 | ||
881c5149 DH |
1741 | config TEST_STRING_HELPERS |
1742 | tristate "Test functions located in the string_helpers module at runtime" | |
1743 | ||
1744 | config TEST_KSTRTOX | |
1745 | tristate "Test kstrto*() family of functions at runtime" | |
1746 | ||
707cc728 RV |
1747 | config TEST_PRINTF |
1748 | tristate "Test printf() family of functions at runtime" | |
1749 | ||
7e1e7763 | 1750 | config TEST_RHASHTABLE |
9d6dbe1b | 1751 | tristate "Perform selftest on resizable hash table" |
7e1e7763 TG |
1752 | default n |
1753 | help | |
1754 | Enable this option to test the rhashtable functions at boot. | |
1755 | ||
1756 | If unsure, say N. | |
1757 | ||
881c5149 DH |
1758 | endmenu # runtime tests |
1759 | ||
f212ec4b | 1760 | config PROVIDE_OHCI1394_DMA_INIT |
080de8c2 | 1761 | bool "Remote debugging over FireWire early on boot" |
f212ec4b BK |
1762 | depends on PCI && X86 |
1763 | help | |
1764 | If you want to debug problems which hang or crash the kernel early | |
1765 | on boot and the crashing machine has a FireWire port, you can use | |
1766 | this feature to remotely access the memory of the crashed machine | |
1767 | over FireWire. This employs remote DMA as part of the OHCI1394 | |
1768 | specification which is now the standard for FireWire controllers. | |
1769 | ||
1770 | With remote DMA, you can monitor the printk buffer remotely using | |
1771 | firescope and access all memory below 4GB using fireproxy from gdb. | |
1772 | Even controlling a kernel debugger is possible using remote DMA. | |
1773 | ||
1774 | Usage: | |
1775 | ||
1776 | If ohci1394_dma=early is used as boot parameter, it will initialize | |
1777 | all OHCI1394 controllers which are found in the PCI config space. | |
1778 | ||
1779 | As all changes to the FireWire bus such as enabling and disabling | |
1780 | devices cause a bus reset and thereby disable remote DMA for all | |
1781 | devices, be sure to have the cable plugged and FireWire enabled on | |
1782 | the debugging host before booting the debug target for debugging. | |
1783 | ||
1784 | This code (~1k) is freed after boot. By then, the firewire stack | |
1785 | in charge of the OHCI-1394 controllers should be used instead. | |
1786 | ||
1787 | See Documentation/debugging-via-ohci1394.txt for more information. | |
9745512c | 1788 | |
152de30b | 1789 | config BUILD_DOCSRC |
3794f3e8 RD |
1790 | bool "Build targets in Documentation/ tree" |
1791 | depends on HEADERS_CHECK | |
1792 | help | |
1793 | This option attempts to build objects from the source files in the | |
1794 | kernel Documentation/ tree. | |
1795 | ||
1796 | Say N if you are unsure. | |
1797 | ||
5ee00bd4 JR |
1798 | config DMA_API_DEBUG |
1799 | bool "Enable debugging of DMA-API usage" | |
1800 | depends on HAVE_DMA_API_DEBUG | |
1801 | help | |
1802 | Enable this option to debug the use of the DMA API by device drivers. | |
1803 | With this option you will be able to detect common bugs in device | |
1804 | drivers like double-freeing of DMA mappings or freeing mappings that | |
1805 | were never allocated. | |
0abdd7a8 DW |
1806 | |
1807 | This also attempts to catch cases where a page owned by DMA is | |
1808 | accessed by the cpu in a way that could cause data corruption. For | |
1809 | example, this enables cow_user_page() to check that the source page is | |
1810 | not undergoing DMA. | |
1811 | ||
1812 | This option causes a performance degradation. Use only if you want to | |
1813 | debug device drivers and dma interactions. | |
1814 | ||
1815 | If unsure, say N. | |
346e15be | 1816 | |
8a6f0b47 | 1817 | config TEST_LKM |
93e9ef83 KC |
1818 | tristate "Test module loading with 'hello world' module" |
1819 | default n | |
1820 | depends on m | |
1821 | help | |
1822 | This builds the "test_module" module that emits "Hello, world" | |
1823 | on printk when loaded. It is designed to be used for basic | |
1824 | evaluation of the module loading subsystem (for example when | |
1825 | validating module verification). It lacks any extra dependencies, | |
1826 | and will not normally be loaded by the system unless explicitly | |
1827 | requested by name. | |
1828 | ||
1829 | If unsure, say N. | |
1830 | ||
3e2a4c18 KC |
1831 | config TEST_USER_COPY |
1832 | tristate "Test user/kernel boundary protections" | |
1833 | default n | |
1834 | depends on m | |
1835 | help | |
1836 | This builds the "test_user_copy" module that runs sanity checks | |
1837 | on the copy_to/from_user infrastructure, making sure basic | |
1838 | user/kernel boundary testing is working. If it fails to load, | |
1839 | a regression has been detected in the user/kernel memory boundary | |
1840 | protections. | |
1841 | ||
1842 | If unsure, say N. | |
1843 | ||
64a8946b AS |
1844 | config TEST_BPF |
1845 | tristate "Test BPF filter functionality" | |
1846 | default n | |
98920ba6 | 1847 | depends on m && NET |
64a8946b AS |
1848 | help |
1849 | This builds the "test_bpf" module that runs various test vectors | |
1850 | against the BPF interpreter or BPF JIT compiler depending on the | |
1851 | current setting. This is in particular useful for BPF JIT compiler | |
1852 | development, but also to run regression tests against changes in | |
3c731eba AS |
1853 | the interpreter code. It also enables test stubs for eBPF maps and |
1854 | verifier used by user space verifier testsuite. | |
64a8946b AS |
1855 | |
1856 | If unsure, say N. | |
1857 | ||
0a8adf58 KC |
1858 | config TEST_FIRMWARE |
1859 | tristate "Test firmware loading via userspace interface" | |
1860 | default n | |
1861 | depends on FW_LOADER | |
1862 | help | |
1863 | This builds the "test_firmware" module that creates a userspace | |
1864 | interface for testing firmware loading. This can be used to | |
1865 | control the triggering of firmware loading without needing an | |
1866 | actual firmware-using device. The contents can be rechecked by | |
1867 | userspace. | |
1868 | ||
1869 | If unsure, say N. | |
1870 | ||
e704f93a DR |
1871 | config TEST_UDELAY |
1872 | tristate "udelay test driver" | |
1873 | default n | |
1874 | help | |
1875 | This builds the "udelay_test" module that helps to make sure | |
1876 | that udelay() is working properly. | |
1877 | ||
1878 | If unsure, say N. | |
1879 | ||
4a20799d VM |
1880 | config MEMTEST |
1881 | bool "Memtest" | |
1882 | depends on HAVE_MEMBLOCK | |
1883 | ---help--- | |
1884 | This option adds a kernel parameter 'memtest', which allows memtest | |
1885 | to be set. | |
1886 | memtest=0, mean disabled; -- default | |
1887 | memtest=1, mean do 1 test pattern; | |
1888 | ... | |
8d8cfb47 | 1889 | memtest=17, mean do 17 test patterns. |
4a20799d VM |
1890 | If you are unsure how to answer this question, answer N. |
1891 | ||
2bf9e0ab IM |
1892 | config TEST_STATIC_KEYS |
1893 | tristate "Test static keys" | |
579e1acb JB |
1894 | default n |
1895 | depends on m | |
1896 | help | |
2bf9e0ab | 1897 | Test the static key interfaces. |
579e1acb JB |
1898 | |
1899 | If unsure, say N. | |
1900 | ||
267c4025 | 1901 | source "samples/Kconfig" |
dc7d5527 JW |
1902 | |
1903 | source "lib/Kconfig.kgdb" | |
0a4af3b0 | 1904 |