]>
Commit | Line | Data |
---|---|---|
ec8f24b7 | 1 | # SPDX-License-Identifier: GPL-2.0-only |
06ec64b8 CH |
2 | menu "Kernel hacking" |
3 | ||
604ff0dc | 4 | menu "printk and dmesg options" |
1da177e4 LT |
5 | |
6 | config PRINTK_TIME | |
7 | bool "Show timing information on printks" | |
d3b8b6e5 | 8 | depends on PRINTK |
1da177e4 | 9 | help |
649e6ee3 KS |
10 | Selecting this option causes time stamps of the printk() |
11 | messages to be added to the output of the syslog() system | |
12 | call and at the console. | |
13 | ||
14 | The timestamp is always recorded internally, and exported | |
15 | to /dev/kmsg. This flag just specifies if the timestamp should | |
16 | be included, not that the timestamp is recorded. | |
17 | ||
18 | The behavior is also controlled by the kernel command line | |
8c27ceff | 19 | parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst |
1da177e4 | 20 | |
15ff2069 TH |
21 | config PRINTK_CALLER |
22 | bool "Show caller information on printks" | |
23 | depends on PRINTK | |
24 | help | |
25 | Selecting this option causes printk() to add a caller "thread id" (if | |
26 | in task context) or a caller "processor id" (if not in task context) | |
27 | to every message. | |
28 | ||
29 | This option is intended for environments where multiple threads | |
30 | concurrently call printk() for many times, for it is difficult to | |
31 | interpret without knowing where these lines (or sometimes individual | |
32 | line which was divided into multiple lines due to race) came from. | |
33 | ||
34 | Since toggling after boot makes the code racy, currently there is | |
35 | no option to enable/disable at the kernel command line parameter or | |
36 | sysfs interface. | |
37 | ||
a8cfdc68 OJ |
38 | config CONSOLE_LOGLEVEL_DEFAULT |
39 | int "Default console loglevel (1-15)" | |
40 | range 1 15 | |
41 | default "7" | |
42 | help | |
43 | Default loglevel to determine what will be printed on the console. | |
44 | ||
45 | Setting a default here is equivalent to passing in loglevel=<x> in | |
46 | the kernel bootargs. loglevel=<x> continues to override whatever | |
47 | value is specified here as well. | |
48 | ||
50f4d9bd | 49 | Note: This does not affect the log level of un-prefixed printk() |
a8cfdc68 OJ |
50 | usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT |
51 | option. | |
52 | ||
22eceb8b HG |
53 | config CONSOLE_LOGLEVEL_QUIET |
54 | int "quiet console loglevel (1-15)" | |
55 | range 1 15 | |
56 | default "4" | |
57 | help | |
58 | loglevel to use when "quiet" is passed on the kernel commandline. | |
59 | ||
60 | When "quiet" is passed on the kernel commandline this loglevel | |
61 | will be used as the loglevel. IOW passing "quiet" will be the | |
62 | equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>" | |
63 | ||
42a9dc0b | 64 | config MESSAGE_LOGLEVEL_DEFAULT |
5af5bcb8 MSB |
65 | int "Default message log level (1-7)" |
66 | range 1 7 | |
67 | default "4" | |
68 | help | |
69 | Default log level for printk statements with no specified priority. | |
70 | ||
71 | This was hard-coded to KERN_WARNING since at least 2.6.10 but folks | |
72 | that are auditing their logs closely may want to set it to a lower | |
73 | priority. | |
74 | ||
a8cfdc68 OJ |
75 | Note: This does not affect what message level gets printed on the console |
76 | by default. To change that, use loglevel=<x> in the kernel bootargs, | |
77 | or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value. | |
78 | ||
604ff0dc DH |
79 | config BOOT_PRINTK_DELAY |
80 | bool "Delay each boot printk message by N milliseconds" | |
81 | depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY | |
82 | help | |
83 | This build option allows you to read kernel boot messages | |
84 | by inserting a short delay after each one. The delay is | |
85 | specified in milliseconds on the kernel command line, | |
86 | using "boot_delay=N". | |
87 | ||
88 | It is likely that you would also need to use "lpj=M" to preset | |
89 | the "loops per jiffie" value. | |
90 | See a previous boot log for the "lpj" value to use for your | |
91 | system, and then set "lpj=M" before setting "boot_delay=N". | |
92 | NOTE: Using this option may adversely affect SMP systems. | |
93 | I.e., processors other than the first one may not boot up. | |
94 | BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect | |
95 | what it believes to be lockup conditions. | |
96 | ||
97 | config DYNAMIC_DEBUG | |
98 | bool "Enable dynamic printk() support" | |
99 | default n | |
100 | depends on PRINTK | |
101 | depends on DEBUG_FS | |
102 | help | |
103 | ||
104 | Compiles debug level messages into the kernel, which would not | |
105 | otherwise be available at runtime. These messages can then be | |
106 | enabled/disabled based on various levels of scope - per source file, | |
107 | function, module, format string, and line number. This mechanism | |
108 | implicitly compiles in all pr_debug() and dev_dbg() calls, which | |
109 | enlarges the kernel text size by about 2%. | |
110 | ||
111 | If a source file is compiled with DEBUG flag set, any | |
112 | pr_debug() calls in it are enabled by default, but can be | |
113 | disabled at runtime as below. Note that DEBUG flag is | |
114 | turned on by many CONFIG_*DEBUG* options. | |
115 | ||
116 | Usage: | |
117 | ||
118 | Dynamic debugging is controlled via the 'dynamic_debug/control' file, | |
119 | which is contained in the 'debugfs' filesystem. Thus, the debugfs | |
120 | filesystem must first be mounted before making use of this feature. | |
121 | We refer the control file as: <debugfs>/dynamic_debug/control. This | |
122 | file contains a list of the debug statements that can be enabled. The | |
123 | format for each line of the file is: | |
124 | ||
125 | filename:lineno [module]function flags format | |
126 | ||
127 | filename : source file of the debug statement | |
128 | lineno : line number of the debug statement | |
129 | module : module that contains the debug statement | |
130 | function : function that contains the debug statement | |
131 | flags : '=p' means the line is turned 'on' for printing | |
132 | format : the format used for the debug statement | |
133 | ||
134 | From a live system: | |
135 | ||
136 | nullarbor:~ # cat <debugfs>/dynamic_debug/control | |
137 | # filename:lineno [module]function flags format | |
138 | fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012" | |
139 | fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012" | |
140 | fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012" | |
141 | ||
142 | Example usage: | |
143 | ||
144 | // enable the message at line 1603 of file svcsock.c | |
145 | nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' > | |
146 | <debugfs>/dynamic_debug/control | |
147 | ||
148 | // enable all the messages in file svcsock.c | |
149 | nullarbor:~ # echo -n 'file svcsock.c +p' > | |
150 | <debugfs>/dynamic_debug/control | |
151 | ||
152 | // enable all the messages in the NFS server module | |
153 | nullarbor:~ # echo -n 'module nfsd +p' > | |
154 | <debugfs>/dynamic_debug/control | |
155 | ||
156 | // enable all 12 messages in the function svc_process() | |
157 | nullarbor:~ # echo -n 'func svc_process +p' > | |
158 | <debugfs>/dynamic_debug/control | |
159 | ||
160 | // disable all 12 messages in the function svc_process() | |
161 | nullarbor:~ # echo -n 'func svc_process -p' > | |
162 | <debugfs>/dynamic_debug/control | |
163 | ||
f8998c22 HH |
164 | See Documentation/admin-guide/dynamic-debug-howto.rst for additional |
165 | information. | |
604ff0dc DH |
166 | |
167 | endmenu # "printk and dmesg options" | |
168 | ||
6dfc0665 DH |
169 | menu "Compile-time checks and compiler options" |
170 | ||
171 | config DEBUG_INFO | |
172 | bool "Compile the kernel with debug info" | |
12b13835 | 173 | depends on DEBUG_KERNEL && !COMPILE_TEST |
6dfc0665 DH |
174 | help |
175 | If you say Y here the resulting kernel image will include | |
176 | debugging info resulting in a larger kernel image. | |
177 | This adds debug symbols to the kernel and modules (gcc -g), and | |
178 | is needed if you intend to use kernel crashdump or binary object | |
179 | tools like crash, kgdb, LKCD, gdb, etc on the kernel. | |
180 | Say Y here only if you plan to debug the kernel. | |
181 | ||
182 | If unsure, say N. | |
183 | ||
184 | config DEBUG_INFO_REDUCED | |
185 | bool "Reduce debugging information" | |
186 | depends on DEBUG_INFO | |
187 | help | |
188 | If you say Y here gcc is instructed to generate less debugging | |
189 | information for structure types. This means that tools that | |
190 | need full debugging information (like kgdb or systemtap) won't | |
191 | be happy. But if you merely need debugging information to | |
192 | resolve line numbers there is no loss. Advantage is that | |
193 | build directory object sizes shrink dramatically over a full | |
194 | DEBUG_INFO build and compile times are reduced too. | |
195 | Only works with newer gcc versions. | |
196 | ||
866ced95 AK |
197 | config DEBUG_INFO_SPLIT |
198 | bool "Produce split debuginfo in .dwo files" | |
a687a533 | 199 | depends on DEBUG_INFO |
9d937444 | 200 | depends on $(cc-option,-gsplit-dwarf) |
866ced95 AK |
201 | help |
202 | Generate debug info into separate .dwo files. This significantly | |
203 | reduces the build directory size for builds with DEBUG_INFO, | |
204 | because it stores the information only once on disk in .dwo | |
205 | files instead of multiple times in object files and executables. | |
206 | In addition the debug information is also compressed. | |
207 | ||
208 | Requires recent gcc (4.7+) and recent gdb/binutils. | |
209 | Any tool that packages or reads debug information would need | |
210 | to know about the .dwo files and include them. | |
211 | Incompatible with older versions of ccache. | |
212 | ||
bfaf2dd3 AK |
213 | config DEBUG_INFO_DWARF4 |
214 | bool "Generate dwarf4 debuginfo" | |
215 | depends on DEBUG_INFO | |
9d937444 | 216 | depends on $(cc-option,-gdwarf-4) |
bfaf2dd3 AK |
217 | help |
218 | Generate dwarf4 debug info. This requires recent versions | |
219 | of gcc and gdb. It makes the debug information larger. | |
220 | But it significantly improves the success of resolving | |
221 | variables in gdb on optimized code. | |
222 | ||
e83b9f55 AN |
223 | config DEBUG_INFO_BTF |
224 | bool "Generate BTF typeinfo" | |
225 | depends on DEBUG_INFO | |
226 | help | |
227 | Generate deduplicated BTF type information from DWARF debug info. | |
228 | Turning this on expects presence of pahole tool, which will convert | |
229 | DWARF type info into equivalent deduplicated BTF type info. | |
230 | ||
3ee7b3fa JK |
231 | config GDB_SCRIPTS |
232 | bool "Provide GDB scripts for kernel debugging" | |
233 | depends on DEBUG_INFO | |
234 | help | |
235 | This creates the required links to GDB helper scripts in the | |
236 | build directory. If you load vmlinux into gdb, the helper | |
237 | scripts will be automatically imported by gdb as well, and | |
238 | additional functions are available to analyze a Linux kernel | |
700199b0 AP |
239 | instance. See Documentation/dev-tools/gdb-kernel-debugging.rst |
240 | for further details. | |
3ee7b3fa | 241 | |
cebc04ba AM |
242 | config ENABLE_MUST_CHECK |
243 | bool "Enable __must_check logic" | |
244 | default y | |
245 | help | |
246 | Enable the __must_check logic in the kernel build. Disable this to | |
247 | suppress the "warning: ignoring return value of 'foo', declared with | |
248 | attribute warn_unused_result" messages. | |
1da177e4 | 249 | |
35bb5b1e AK |
250 | config FRAME_WARN |
251 | int "Warn for stack frames larger than (needs gcc 4.4)" | |
252 | range 0 8192 | |
0e07f663 | 253 | default 2048 if GCC_PLUGIN_LATENT_ENTROPY |
432654df HD |
254 | default 1280 if (!64BIT && PARISC) |
255 | default 1024 if (!64BIT && !PARISC) | |
35bb5b1e AK |
256 | default 2048 if 64BIT |
257 | help | |
258 | Tell gcc to warn at build time for stack frames larger than this. | |
259 | Setting this too low will cause a lot of warnings. | |
260 | Setting it to 0 disables the warning. | |
261 | Requires gcc 4.4 | |
262 | ||
99657c78 RD |
263 | config STRIP_ASM_SYMS |
264 | bool "Strip assembler-generated symbols during link" | |
265 | default n | |
266 | help | |
267 | Strip internal assembler-generated symbols during a link (symbols | |
268 | that look like '.Lxxx') so they don't pollute the output of | |
269 | get_wchan() and suchlike. | |
270 | ||
1873e870 AK |
271 | config READABLE_ASM |
272 | bool "Generate readable assembler code" | |
273 | depends on DEBUG_KERNEL | |
274 | help | |
275 | Disable some compiler optimizations that tend to generate human unreadable | |
276 | assembler output. This may make the kernel slightly slower, but it helps | |
277 | to keep kernel developers who have to stare a lot at assembler listings | |
278 | sane. | |
279 | ||
f71d20e9 AV |
280 | config UNUSED_SYMBOLS |
281 | bool "Enable unused/obsolete exported symbols" | |
282 | default y if X86 | |
283 | help | |
284 | Unused but exported symbols make the kernel needlessly bigger. For | |
285 | that reason most of these unused exports will soon be removed. This | |
286 | option is provided temporarily to provide a transition period in case | |
287 | some external kernel module needs one of these symbols anyway. If you | |
288 | encounter such a case in your module, consider if you are actually | |
289 | using the right API. (rationale: since nobody in the kernel is using | |
290 | this in a module, there is a pretty good chance it's actually the | |
291 | wrong interface to use). If you really need the symbol, please send a | |
292 | mail to the linux kernel mailing list mentioning the symbol and why | |
293 | you really need it, and what the merge plan to the mainline kernel for | |
294 | your module is. | |
295 | ||
bf4735a4 DM |
296 | config DEBUG_FS |
297 | bool "Debug Filesystem" | |
bf4735a4 DM |
298 | help |
299 | debugfs is a virtual file system that kernel developers use to put | |
300 | debugging files into. Enable this option to be able to read and | |
301 | write to these files. | |
302 | ||
ff543332 | 303 | For detailed documentation on the debugfs API, see |
e1b4fc7a | 304 | Documentation/filesystems/. |
ff543332 | 305 | |
bf4735a4 DM |
306 | If unsure, say N. |
307 | ||
e949f4c2 MY |
308 | config HEADERS_INSTALL |
309 | bool "Install uapi headers to usr/include" | |
bf4735a4 DM |
310 | depends on !UML |
311 | help | |
e949f4c2 MY |
312 | This option will install uapi headers (headers exported to user-space) |
313 | into the usr/include directory for use during the kernel build. | |
314 | This is unneeded for building the kernel itself, but needed for some | |
315 | user-space program samples. It is also needed by some features such | |
316 | as uapi header sanity checks. | |
317 | ||
bf4735a4 | 318 | config HEADERS_CHECK |
c6509a24 | 319 | bool "Run sanity checks on uapi headers when building 'all'" |
e949f4c2 | 320 | depends on HEADERS_INSTALL |
bf4735a4 | 321 | help |
e949f4c2 MY |
322 | This option will run basic sanity checks on uapi headers when |
323 | building the 'all' target, for example, ensure that they do not | |
324 | attempt to include files which were not exported, etc. | |
bf4735a4 DM |
325 | |
326 | If you're making modifications to header files which are | |
59b2bd05 | 327 | relevant for userspace, say 'Y'. |
bf4735a4 | 328 | |
9012d011 MY |
329 | config OPTIMIZE_INLINING |
330 | bool "Allow compiler to uninline functions marked 'inline'" | |
331 | help | |
332 | This option determines if the kernel forces gcc to inline the functions | |
333 | developers have marked 'inline'. Doing so takes away freedom from gcc to | |
334 | do what it thinks is best, which is desirable for the gcc 3.x series of | |
335 | compilers. The gcc 4.x series have a rewritten inlining algorithm and | |
336 | enabling this option will generate a smaller kernel there. Hopefully | |
337 | this algorithm is so good that allowing gcc 4.x and above to make the | |
338 | decision will become the default in the future. Until then this option | |
339 | is there to test gcc for this. | |
340 | ||
341 | If unsure, say N. | |
342 | ||
91341d4b SR |
343 | config DEBUG_SECTION_MISMATCH |
344 | bool "Enable full Section mismatch analysis" | |
91341d4b SR |
345 | help |
346 | The section mismatch analysis checks if there are illegal | |
347 | references from one section to another section. | |
e809ab01 MW |
348 | During linktime or runtime, some sections are dropped; |
349 | any use of code/data previously in these sections would | |
91341d4b | 350 | most likely result in an oops. |
e809ab01 | 351 | In the code, functions and variables are annotated with |
0db0628d | 352 | __init,, etc. (see the full list in include/linux/init.h), |
d6fbfa4f | 353 | which results in the code/data being placed in specific sections. |
e809ab01 MW |
354 | The section mismatch analysis is always performed after a full |
355 | kernel build, and enabling this option causes the following | |
b7dca6dd | 356 | additional step to occur: |
e809ab01 MW |
357 | - Add the option -fno-inline-functions-called-once to gcc commands. |
358 | When inlining a function annotated with __init in a non-init | |
359 | function, we would lose the section information and thus | |
91341d4b | 360 | the analysis would not catch the illegal reference. |
e809ab01 MW |
361 | This option tells gcc to inline less (but it does result in |
362 | a larger kernel). | |
91341d4b | 363 | |
47490ec1 NB |
364 | config SECTION_MISMATCH_WARN_ONLY |
365 | bool "Make section mismatch errors non-fatal" | |
366 | default y | |
367 | help | |
368 | If you say N here, the build process will fail if there are any | |
369 | section mismatch, instead of just throwing warnings. | |
370 | ||
371 | If unsure, say Y. | |
372 | ||
6dfc0665 DH |
373 | # |
374 | # Select this config option from the architecture Kconfig, if it | |
375 | # is preferred to always offer frame pointers as a config | |
376 | # option on the architecture (regardless of KERNEL_DEBUG): | |
377 | # | |
378 | config ARCH_WANT_FRAME_POINTERS | |
379 | bool | |
f346f4b3 | 380 | |
6dfc0665 DH |
381 | config FRAME_POINTER |
382 | bool "Compile the kernel with frame pointers" | |
a687a533 | 383 | depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS |
6dfc0665 | 384 | default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS |
a304e1b8 | 385 | help |
6dfc0665 DH |
386 | If you say Y here the resulting kernel image will be slightly |
387 | larger and slower, but it gives very useful debugging information | |
388 | in case of kernel bugs. (precise oopses/stacktraces/warnings) | |
a304e1b8 | 389 | |
b9ab5ebb JP |
390 | config STACK_VALIDATION |
391 | bool "Compile-time stack metadata validation" | |
392 | depends on HAVE_STACK_VALIDATION | |
393 | default n | |
394 | help | |
395 | Add compile-time checks to validate stack metadata, including frame | |
396 | pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure | |
397 | that runtime stack traces are more reliable. | |
398 | ||
ee9f8fce | 399 | This is also a prerequisite for generation of ORC unwind data, which |
11af8474 | 400 | is needed for CONFIG_UNWINDER_ORC. |
ee9f8fce | 401 | |
b9ab5ebb JP |
402 | For more information, see |
403 | tools/objtool/Documentation/stack-validation.txt. | |
404 | ||
6dfc0665 DH |
405 | config DEBUG_FORCE_WEAK_PER_CPU |
406 | bool "Force weak per-cpu definitions" | |
407 | depends on DEBUG_KERNEL | |
8446f1d3 | 408 | help |
6dfc0665 DH |
409 | s390 and alpha require percpu variables in modules to be |
410 | defined weak to work around addressing range issue which | |
411 | puts the following two restrictions on percpu variable | |
412 | definitions. | |
8446f1d3 | 413 | |
6dfc0665 DH |
414 | 1. percpu symbols must be unique whether static or not |
415 | 2. percpu variables can't be defined inside a function | |
8446f1d3 | 416 | |
6dfc0665 DH |
417 | To ensure that generic code follows the above rules, this |
418 | option forces all percpu variables to be defined as weak. | |
5f329089 | 419 | |
6dfc0665 | 420 | endmenu # "Compiler options" |
8446f1d3 | 421 | |
6dfc0665 DH |
422 | config MAGIC_SYSRQ |
423 | bool "Magic SysRq key" | |
424 | depends on !UML | |
425 | help | |
426 | If you say Y here, you will have some control over the system even | |
427 | if the system crashes for example during kernel debugging (e.g., you | |
428 | will be able to flush the buffer cache to disk, reboot the system | |
429 | immediately or dump some status information). This is accomplished | |
430 | by pressing various keys while holding SysRq (Alt+PrintScreen). It | |
431 | also works on a serial console (on PC hardware at least), if you | |
432 | send a BREAK and then within 5 seconds a command keypress. The | |
f8998c22 HH |
433 | keys are documented in <file:Documentation/admin-guide/sysrq.rst>. |
434 | Don't say Y unless you really know what this hack does. | |
8446f1d3 | 435 | |
8eaede49 BH |
436 | config MAGIC_SYSRQ_DEFAULT_ENABLE |
437 | hex "Enable magic SysRq key functions by default" | |
438 | depends on MAGIC_SYSRQ | |
439 | default 0x1 | |
440 | help | |
441 | Specifies which SysRq key functions are enabled by default. | |
442 | This may be set to 1 or 0 to enable or disable them all, or | |
f8998c22 | 443 | to a bitmask as described in Documentation/admin-guide/sysrq.rst. |
8eaede49 | 444 | |
732dbf3a FF |
445 | config MAGIC_SYSRQ_SERIAL |
446 | bool "Enable magic SysRq key over serial" | |
447 | depends on MAGIC_SYSRQ | |
448 | default y | |
449 | help | |
450 | Many embedded boards have a disconnected TTL level serial which can | |
451 | generate some garbage that can lead to spurious false sysrq detects. | |
452 | This option allows you to decide whether you want to enable the | |
453 | magic SysRq key. | |
454 | ||
f346f4b3 AB |
455 | config DEBUG_KERNEL |
456 | bool "Kernel debugging" | |
fef2c9bc | 457 | help |
f346f4b3 AB |
458 | Say Y here if you are developing drivers or trying to debug and |
459 | identify kernel problems. | |
fef2c9bc | 460 | |
c66d7a27 SK |
461 | config DEBUG_MISC |
462 | bool "Miscellaneous debug code" | |
463 | default DEBUG_KERNEL | |
464 | depends on DEBUG_KERNEL | |
465 | help | |
466 | Say Y here if you need to enable miscellaneous debug code that should | |
467 | be under a more specific debug option but isn't. | |
468 | ||
469 | ||
0610c8a8 | 470 | menu "Memory Debugging" |
fef2c9bc | 471 | |
8636a1f9 | 472 | source "mm/Kconfig.debug" |
fef2c9bc | 473 | |
0610c8a8 DH |
474 | config DEBUG_OBJECTS |
475 | bool "Debug object operations" | |
476 | depends on DEBUG_KERNEL | |
9c44bc03 | 477 | help |
0610c8a8 DH |
478 | If you say Y here, additional code will be inserted into the |
479 | kernel to track the life time of various objects and validate | |
480 | the operations on those objects. | |
9c44bc03 | 481 | |
0610c8a8 DH |
482 | config DEBUG_OBJECTS_SELFTEST |
483 | bool "Debug objects selftest" | |
484 | depends on DEBUG_OBJECTS | |
485 | help | |
486 | This enables the selftest of the object debug code. | |
9c44bc03 | 487 | |
0610c8a8 DH |
488 | config DEBUG_OBJECTS_FREE |
489 | bool "Debug objects in freed memory" | |
490 | depends on DEBUG_OBJECTS | |
491 | help | |
492 | This enables checks whether a k/v free operation frees an area | |
493 | which contains an object which has not been deactivated | |
494 | properly. This can make kmalloc/kfree-intensive workloads | |
495 | much slower. | |
3ac7fe5a | 496 | |
c6f3a97f TG |
497 | config DEBUG_OBJECTS_TIMERS |
498 | bool "Debug timer objects" | |
499 | depends on DEBUG_OBJECTS | |
500 | help | |
501 | If you say Y here, additional code will be inserted into the | |
502 | timer routines to track the life time of timer objects and | |
503 | validate the timer operations. | |
504 | ||
dc186ad7 TG |
505 | config DEBUG_OBJECTS_WORK |
506 | bool "Debug work objects" | |
507 | depends on DEBUG_OBJECTS | |
508 | help | |
509 | If you say Y here, additional code will be inserted into the | |
510 | work queue routines to track the life time of work objects and | |
511 | validate the work operations. | |
512 | ||
551d55a9 MD |
513 | config DEBUG_OBJECTS_RCU_HEAD |
514 | bool "Debug RCU callbacks objects" | |
fc2ecf7e | 515 | depends on DEBUG_OBJECTS |
551d55a9 MD |
516 | help |
517 | Enable this to turn on debugging of RCU list heads (call_rcu() usage). | |
518 | ||
e2852ae8 TH |
519 | config DEBUG_OBJECTS_PERCPU_COUNTER |
520 | bool "Debug percpu counter objects" | |
521 | depends on DEBUG_OBJECTS | |
522 | help | |
523 | If you say Y here, additional code will be inserted into the | |
524 | percpu counter routines to track the life time of percpu counter | |
525 | objects and validate the percpu counter operations. | |
526 | ||
3ae70205 IM |
527 | config DEBUG_OBJECTS_ENABLE_DEFAULT |
528 | int "debug_objects bootup default value (0-1)" | |
529 | range 0 1 | |
530 | default "1" | |
531 | depends on DEBUG_OBJECTS | |
532 | help | |
533 | Debug objects boot parameter default value | |
534 | ||
1da177e4 | 535 | config DEBUG_SLAB |
4a2f0acf | 536 | bool "Debug slab memory allocations" |
4675ff05 | 537 | depends on DEBUG_KERNEL && SLAB |
1da177e4 LT |
538 | help |
539 | Say Y here to have the kernel do limited verification on memory | |
540 | allocation as well as poisoning memory on free to catch use of freed | |
541 | memory. This can make kmalloc/kfree-intensive workloads much slower. | |
542 | ||
f0630fff CL |
543 | config SLUB_DEBUG_ON |
544 | bool "SLUB debugging on by default" | |
4675ff05 | 545 | depends on SLUB && SLUB_DEBUG |
f0630fff CL |
546 | default n |
547 | help | |
548 | Boot with debugging on by default. SLUB boots by default with | |
549 | the runtime debug capabilities switched off. Enabling this is | |
550 | equivalent to specifying the "slub_debug" parameter on boot. | |
551 | There is no support for more fine grained debug control like | |
552 | possible with slub_debug=xxx. SLUB debugging may be switched | |
553 | off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying | |
554 | "slub_debug=-". | |
555 | ||
8ff12cfc CL |
556 | config SLUB_STATS |
557 | default n | |
558 | bool "Enable SLUB performance statistics" | |
ab4d5ed5 | 559 | depends on SLUB && SYSFS |
8ff12cfc CL |
560 | help |
561 | SLUB statistics are useful to debug SLUBs allocation behavior in | |
562 | order find ways to optimize the allocator. This should never be | |
563 | enabled for production use since keeping statistics slows down | |
564 | the allocator by a few percentage points. The slabinfo command | |
565 | supports the determination of the most active slabs to figure | |
566 | out which slabs are relevant to a particular load. | |
567 | Try running: slabinfo -DA | |
568 | ||
b69ec42b CM |
569 | config HAVE_DEBUG_KMEMLEAK |
570 | bool | |
571 | ||
3bba00d7 CM |
572 | config DEBUG_KMEMLEAK |
573 | bool "Kernel memory leak detector" | |
525c1f92 | 574 | depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK |
79e0d9bd | 575 | select DEBUG_FS |
3bba00d7 CM |
576 | select STACKTRACE if STACKTRACE_SUPPORT |
577 | select KALLSYMS | |
b60e26a2 | 578 | select CRC32 |
3bba00d7 CM |
579 | help |
580 | Say Y here if you want to enable the memory leak | |
581 | detector. The memory allocation/freeing is traced in a way | |
582 | similar to the Boehm's conservative garbage collector, the | |
583 | difference being that the orphan objects are not freed but | |
584 | only shown in /sys/kernel/debug/kmemleak. Enabling this | |
585 | feature will introduce an overhead to memory | |
700199b0 | 586 | allocations. See Documentation/dev-tools/kmemleak.rst for more |
3bba00d7 CM |
587 | details. |
588 | ||
0610c8a8 DH |
589 | Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances |
590 | of finding leaks due to the slab objects poisoning. | |
591 | ||
592 | In order to access the kmemleak file, debugfs needs to be | |
593 | mounted (usually at /sys/kernel/debug). | |
594 | ||
595 | config DEBUG_KMEMLEAK_EARLY_LOG_SIZE | |
596 | int "Maximum kmemleak early log entries" | |
597 | depends on DEBUG_KMEMLEAK | |
598 | range 200 40000 | |
599 | default 400 | |
600 | help | |
601 | Kmemleak must track all the memory allocations to avoid | |
602 | reporting false positives. Since memory may be allocated or | |
603 | freed before kmemleak is initialised, an early log buffer is | |
604 | used to store these actions. If kmemleak reports "early log | |
605 | buffer exceeded", please increase this value. | |
606 | ||
607 | config DEBUG_KMEMLEAK_TEST | |
608 | tristate "Simple test for the kernel memory leak detector" | |
609 | depends on DEBUG_KMEMLEAK && m | |
610 | help | |
611 | This option enables a module that explicitly leaks memory. | |
612 | ||
613 | If unsure, say N. | |
614 | ||
615 | config DEBUG_KMEMLEAK_DEFAULT_OFF | |
616 | bool "Default kmemleak to off" | |
617 | depends on DEBUG_KMEMLEAK | |
618 | help | |
619 | Say Y here to disable kmemleak by default. It can then be enabled | |
620 | on the command line via kmemleak=on. | |
621 | ||
d53ce042 SK |
622 | config DEBUG_KMEMLEAK_AUTO_SCAN |
623 | bool "Enable kmemleak auto scan thread on boot up" | |
624 | default y | |
625 | depends on DEBUG_KMEMLEAK | |
626 | help | |
627 | Depending on the cpu, kmemleak scan may be cpu intensive and can | |
628 | stall user tasks at times. This option enables/disables automatic | |
629 | kmemleak scan at boot up. | |
630 | ||
631 | Say N here to disable kmemleak auto scan thread to stop automatic | |
632 | scanning. Disabling this option disables automatic reporting of | |
633 | memory leaks. | |
634 | ||
635 | If unsure, say Y. | |
636 | ||
0610c8a8 DH |
637 | config DEBUG_STACK_USAGE |
638 | bool "Stack utilization instrumentation" | |
6c31da34 | 639 | depends on DEBUG_KERNEL && !IA64 |
0610c8a8 DH |
640 | help |
641 | Enables the display of the minimum amount of free stack which each | |
642 | task has ever had available in the sysrq-T and sysrq-P debug output. | |
643 | ||
644 | This option will slow down process creation somewhat. | |
645 | ||
646 | config DEBUG_VM | |
647 | bool "Debug VM" | |
648 | depends on DEBUG_KERNEL | |
649 | help | |
650 | Enable this to turn on extended checks in the virtual-memory system | |
651 | that may impact performance. | |
652 | ||
653 | If unsure, say N. | |
654 | ||
4f115147 DB |
655 | config DEBUG_VM_VMACACHE |
656 | bool "Debug VMA caching" | |
657 | depends on DEBUG_VM | |
658 | help | |
659 | Enable this to turn on VMA caching debug information. Doing so | |
660 | can cause significant overhead, so only enable it in non-production | |
661 | environments. | |
662 | ||
663 | If unsure, say N. | |
664 | ||
0610c8a8 DH |
665 | config DEBUG_VM_RB |
666 | bool "Debug VM red-black trees" | |
667 | depends on DEBUG_VM | |
668 | help | |
a663dad6 | 669 | Enable VM red-black tree debugging information and extra validations. |
0610c8a8 DH |
670 | |
671 | If unsure, say N. | |
672 | ||
95ad9755 KS |
673 | config DEBUG_VM_PGFLAGS |
674 | bool "Debug page-flags operations" | |
675 | depends on DEBUG_VM | |
676 | help | |
677 | Enables extra validation on page flags operations. | |
678 | ||
679 | If unsure, say N. | |
680 | ||
fa5b6ec9 LA |
681 | config ARCH_HAS_DEBUG_VIRTUAL |
682 | bool | |
683 | ||
0610c8a8 DH |
684 | config DEBUG_VIRTUAL |
685 | bool "Debug VM translations" | |
fa5b6ec9 | 686 | depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL |
0610c8a8 DH |
687 | help |
688 | Enable some costly sanity checks in virtual to page code. This can | |
689 | catch mistakes with virt_to_page() and friends. | |
690 | ||
691 | If unsure, say N. | |
692 | ||
693 | config DEBUG_NOMMU_REGIONS | |
694 | bool "Debug the global anon/private NOMMU mapping region tree" | |
695 | depends on DEBUG_KERNEL && !MMU | |
696 | help | |
697 | This option causes the global tree of anonymous and private mapping | |
698 | regions to be regularly checked for invalid topology. | |
699 | ||
700 | config DEBUG_MEMORY_INIT | |
701 | bool "Debug memory initialisation" if EXPERT | |
702 | default !EXPERT | |
703 | help | |
704 | Enable this for additional checks during memory initialisation. | |
705 | The sanity checks verify aspects of the VM such as the memory model | |
706 | and other information provided by the architecture. Verbose | |
707 | information will be printed at KERN_DEBUG loglevel depending | |
708 | on the mminit_loglevel= command-line option. | |
709 | ||
710 | If unsure, say Y | |
711 | ||
712 | config MEMORY_NOTIFIER_ERROR_INJECT | |
713 | tristate "Memory hotplug notifier error injection module" | |
714 | depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION | |
715 | help | |
716 | This option provides the ability to inject artificial errors to | |
717 | memory hotplug notifier chain callbacks. It is controlled through | |
718 | debugfs interface under /sys/kernel/debug/notifier-error-inject/memory | |
719 | ||
720 | If the notifier call chain should be failed with some events | |
721 | notified, write the error code to "actions/<notifier event>/error". | |
722 | ||
723 | Example: Inject memory hotplug offline error (-12 == -ENOMEM) | |
724 | ||
725 | # cd /sys/kernel/debug/notifier-error-inject/memory | |
726 | # echo -12 > actions/MEM_GOING_OFFLINE/error | |
727 | # echo offline > /sys/devices/system/memory/memoryXXX/state | |
728 | bash: echo: write error: Cannot allocate memory | |
729 | ||
730 | To compile this code as a module, choose M here: the module will | |
731 | be called memory-notifier-error-inject. | |
732 | ||
733 | If unsure, say N. | |
734 | ||
735 | config DEBUG_PER_CPU_MAPS | |
736 | bool "Debug access to per_cpu maps" | |
737 | depends on DEBUG_KERNEL | |
738 | depends on SMP | |
739 | help | |
740 | Say Y to verify that the per_cpu map being accessed has | |
741 | been set up. This adds a fair amount of code to kernel memory | |
742 | and decreases performance. | |
743 | ||
744 | Say N if unsure. | |
745 | ||
746 | config DEBUG_HIGHMEM | |
747 | bool "Highmem debugging" | |
748 | depends on DEBUG_KERNEL && HIGHMEM | |
749 | help | |
b1357c9f GU |
750 | This option enables additional error checking for high memory |
751 | systems. Disable for production systems. | |
0610c8a8 DH |
752 | |
753 | config HAVE_DEBUG_STACKOVERFLOW | |
754 | bool | |
755 | ||
756 | config DEBUG_STACKOVERFLOW | |
757 | bool "Check for stack overflows" | |
758 | depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW | |
759 | ---help--- | |
760 | Say Y here if you want to check for overflows of kernel, IRQ | |
edb0ec07 | 761 | and exception stacks (if your architecture uses them). This |
0610c8a8 DH |
762 | option will show detailed messages if free stack space drops |
763 | below a certain limit. | |
764 | ||
765 | These kinds of bugs usually occur when call-chains in the | |
766 | kernel get too deep, especially when interrupts are | |
767 | involved. | |
768 | ||
769 | Use this in cases where you see apparently random memory | |
770 | corruption, especially if it appears in 'struct thread_info' | |
771 | ||
772 | If in doubt, say "N". | |
773 | ||
0b24becc AR |
774 | source "lib/Kconfig.kasan" |
775 | ||
0610c8a8 DH |
776 | endmenu # "Memory Debugging" |
777 | ||
5c9a8750 DV |
778 | config ARCH_HAS_KCOV |
779 | bool | |
780 | help | |
40453c4f MR |
781 | An architecture should select this when it can successfully |
782 | build and run with CONFIG_KCOV. This typically requires | |
783 | disabling instrumentation for some early boot code. | |
5c9a8750 | 784 | |
5aadfdeb MY |
785 | config CC_HAS_SANCOV_TRACE_PC |
786 | def_bool $(cc-option,-fsanitize-coverage=trace-pc) | |
787 | ||
5c9a8750 DV |
788 | config KCOV |
789 | bool "Code coverage for fuzzing" | |
790 | depends on ARCH_HAS_KCOV | |
5aadfdeb | 791 | depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS |
5c9a8750 | 792 | select DEBUG_FS |
5aadfdeb | 793 | select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC |
5c9a8750 DV |
794 | help |
795 | KCOV exposes kernel code coverage information in a form suitable | |
796 | for coverage-guided fuzzing (randomized testing). | |
797 | ||
798 | If RANDOMIZE_BASE is enabled, PC values will not be stable across | |
799 | different machines and across reboots. If you need stable PC values, | |
800 | disable RANDOMIZE_BASE. | |
801 | ||
700199b0 | 802 | For more details, see Documentation/dev-tools/kcov.rst. |
5c9a8750 | 803 | |
d677a4d6 VC |
804 | config KCOV_ENABLE_COMPARISONS |
805 | bool "Enable comparison operands collection by KCOV" | |
806 | depends on KCOV | |
5aadfdeb | 807 | depends on $(cc-option,-fsanitize-coverage=trace-cmp) |
d677a4d6 VC |
808 | help |
809 | KCOV also exposes operands of every comparison in the instrumented | |
810 | code along with operand sizes and PCs of the comparison instructions. | |
811 | These operands can be used by fuzzing engines to improve the quality | |
812 | of fuzzing coverage. | |
813 | ||
a4691dea VN |
814 | config KCOV_INSTRUMENT_ALL |
815 | bool "Instrument all code by default" | |
816 | depends on KCOV | |
5aadfdeb | 817 | default y |
a4691dea VN |
818 | help |
819 | If you are doing generic system call fuzzing (like e.g. syzkaller), | |
820 | then you will want to instrument the whole kernel and you should | |
821 | say y here. If you are doing more targeted fuzzing (like e.g. | |
822 | filesystem fuzzing with AFL) then you will want to enable coverage | |
823 | for more specific subsets of files, and should say n here. | |
824 | ||
a304e1b8 DW |
825 | config DEBUG_SHIRQ |
826 | bool "Debug shared IRQ handlers" | |
0244ad00 | 827 | depends on DEBUG_KERNEL |
a304e1b8 DW |
828 | help |
829 | Enable this to generate a spurious interrupt as soon as a shared | |
830 | interrupt handler is registered, and just before one is deregistered. | |
831 | Drivers ought to be able to handle interrupts coming in at those | |
832 | points; some don't and need to be caught. | |
833 | ||
92aef8fb DH |
834 | menu "Debug Lockups and Hangs" |
835 | ||
58687acb | 836 | config LOCKUP_DETECTOR |
05a4a952 NP |
837 | bool |
838 | ||
839 | config SOFTLOCKUP_DETECTOR | |
840 | bool "Detect Soft Lockups" | |
dea20a3f | 841 | depends on DEBUG_KERNEL && !S390 |
05a4a952 | 842 | select LOCKUP_DETECTOR |
8446f1d3 | 843 | help |
58687acb | 844 | Say Y here to enable the kernel to act as a watchdog to detect |
05a4a952 | 845 | soft lockups. |
58687acb DZ |
846 | |
847 | Softlockups are bugs that cause the kernel to loop in kernel | |
5f329089 | 848 | mode for more than 20 seconds, without giving other tasks a |
58687acb DZ |
849 | chance to run. The current stack trace is displayed upon |
850 | detection and the system will stay locked up. | |
8446f1d3 | 851 | |
5f00ae0d RD |
852 | config BOOTPARAM_SOFTLOCKUP_PANIC |
853 | bool "Panic (Reboot) On Soft Lockups" | |
854 | depends on SOFTLOCKUP_DETECTOR | |
855 | help | |
856 | Say Y here to enable the kernel to panic on "soft lockups", | |
857 | which are bugs that cause the kernel to loop in kernel | |
858 | mode for more than 20 seconds (configurable using the watchdog_thresh | |
859 | sysctl), without giving other tasks a chance to run. | |
860 | ||
861 | The panic can be used in combination with panic_timeout, | |
862 | to cause the system to reboot automatically after a | |
863 | lockup has been detected. This feature is useful for | |
864 | high-availability systems that have uptime guarantees and | |
865 | where a lockup must be resolved ASAP. | |
866 | ||
867 | Say N if unsure. | |
868 | ||
869 | config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE | |
870 | int | |
871 | depends on SOFTLOCKUP_DETECTOR | |
872 | range 0 1 | |
873 | default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC | |
874 | default 1 if BOOTPARAM_SOFTLOCKUP_PANIC | |
875 | ||
05a4a952 NP |
876 | config HARDLOCKUP_DETECTOR_PERF |
877 | bool | |
878 | select SOFTLOCKUP_DETECTOR | |
879 | ||
7edaeb68 TG |
880 | # |
881 | # Enables a timestamp based low pass filter to compensate for perf based | |
882 | # hard lockup detection which runs too fast due to turbo modes. | |
883 | # | |
884 | config HARDLOCKUP_CHECK_TIMESTAMP | |
885 | bool | |
886 | ||
05a4a952 NP |
887 | # |
888 | # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard | |
889 | # lockup detector rather than the perf based detector. | |
890 | # | |
891 | config HARDLOCKUP_DETECTOR | |
892 | bool "Detect Hard Lockups" | |
893 | depends on DEBUG_KERNEL && !S390 | |
894 | depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH | |
895 | select LOCKUP_DETECTOR | |
896 | select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF | |
897 | select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH | |
898 | help | |
899 | Say Y here to enable the kernel to act as a watchdog to detect | |
900 | hard lockups. | |
901 | ||
58687acb | 902 | Hardlockups are bugs that cause the CPU to loop in kernel mode |
5f329089 | 903 | for more than 10 seconds, without letting other interrupts have a |
58687acb DZ |
904 | chance to run. The current stack trace is displayed upon detection |
905 | and the system will stay locked up. | |
8446f1d3 | 906 | |
fef2c9bc DZ |
907 | config BOOTPARAM_HARDLOCKUP_PANIC |
908 | bool "Panic (Reboot) On Hard Lockups" | |
8f1f66ed | 909 | depends on HARDLOCKUP_DETECTOR |
fef2c9bc DZ |
910 | help |
911 | Say Y here to enable the kernel to panic on "hard lockups", | |
912 | which are bugs that cause the kernel to loop in kernel | |
5f329089 FLVC |
913 | mode with interrupts disabled for more than 10 seconds (configurable |
914 | using the watchdog_thresh sysctl). | |
fef2c9bc DZ |
915 | |
916 | Say N if unsure. | |
917 | ||
918 | config BOOTPARAM_HARDLOCKUP_PANIC_VALUE | |
919 | int | |
8f1f66ed | 920 | depends on HARDLOCKUP_DETECTOR |
fef2c9bc DZ |
921 | range 0 1 |
922 | default 0 if !BOOTPARAM_HARDLOCKUP_PANIC | |
923 | default 1 if BOOTPARAM_HARDLOCKUP_PANIC | |
924 | ||
e162b39a MSB |
925 | config DETECT_HUNG_TASK |
926 | bool "Detect Hung Tasks" | |
927 | depends on DEBUG_KERNEL | |
05a4a952 | 928 | default SOFTLOCKUP_DETECTOR |
e162b39a | 929 | help |
0610c8a8 DH |
930 | Say Y here to enable the kernel to detect "hung tasks", |
931 | which are bugs that cause the task to be stuck in | |
96b03ab8 | 932 | uninterruptible "D" state indefinitely. |
1da177e4 | 933 | |
0610c8a8 DH |
934 | When a hung task is detected, the kernel will print the |
935 | current stack trace (which you should report), but the | |
936 | task will stay in uninterruptible state. If lockdep is | |
937 | enabled then all held locks will also be reported. This | |
938 | feature has negligible overhead. | |
871751e2 | 939 | |
0610c8a8 DH |
940 | config DEFAULT_HUNG_TASK_TIMEOUT |
941 | int "Default timeout for hung task detection (in seconds)" | |
942 | depends on DETECT_HUNG_TASK | |
943 | default 120 | |
f0630fff | 944 | help |
0610c8a8 DH |
945 | This option controls the default timeout (in seconds) used |
946 | to determine when a task has become non-responsive and should | |
947 | be considered hung. | |
f0630fff | 948 | |
0610c8a8 DH |
949 | It can be adjusted at runtime via the kernel.hung_task_timeout_secs |
950 | sysctl or by writing a value to | |
951 | /proc/sys/kernel/hung_task_timeout_secs. | |
8ff12cfc | 952 | |
0610c8a8 DH |
953 | A timeout of 0 disables the check. The default is two minutes. |
954 | Keeping the default should be fine in most cases. | |
b69ec42b | 955 | |
0610c8a8 DH |
956 | config BOOTPARAM_HUNG_TASK_PANIC |
957 | bool "Panic (Reboot) On Hung Tasks" | |
958 | depends on DETECT_HUNG_TASK | |
3bba00d7 | 959 | help |
0610c8a8 DH |
960 | Say Y here to enable the kernel to panic on "hung tasks", |
961 | which are bugs that cause the kernel to leave a task stuck | |
962 | in uninterruptible "D" state. | |
3bba00d7 | 963 | |
0610c8a8 DH |
964 | The panic can be used in combination with panic_timeout, |
965 | to cause the system to reboot automatically after a | |
966 | hung task has been detected. This feature is useful for | |
967 | high-availability systems that have uptime guarantees and | |
968 | where a hung tasks must be resolved ASAP. | |
bf96d1e3 | 969 | |
0610c8a8 | 970 | Say N if unsure. |
bf96d1e3 | 971 | |
0610c8a8 DH |
972 | config BOOTPARAM_HUNG_TASK_PANIC_VALUE |
973 | int | |
974 | depends on DETECT_HUNG_TASK | |
975 | range 0 1 | |
976 | default 0 if !BOOTPARAM_HUNG_TASK_PANIC | |
977 | default 1 if BOOTPARAM_HUNG_TASK_PANIC | |
3bba00d7 | 978 | |
82607adc TH |
979 | config WQ_WATCHDOG |
980 | bool "Detect Workqueue Stalls" | |
981 | depends on DEBUG_KERNEL | |
982 | help | |
983 | Say Y here to enable stall detection on workqueues. If a | |
984 | worker pool doesn't make forward progress on a pending work | |
985 | item for over a given amount of time, 30s by default, a | |
986 | warning message is printed along with dump of workqueue | |
987 | state. This can be configured through kernel parameter | |
988 | "workqueue.watchdog_thresh" and its sysfs counterpart. | |
989 | ||
92aef8fb DH |
990 | endmenu # "Debug lockups and hangs" |
991 | ||
992 | config PANIC_ON_OOPS | |
993 | bool "Panic on Oops" | |
a9d9058a | 994 | help |
92aef8fb DH |
995 | Say Y here to enable the kernel to panic when it oopses. This |
996 | has the same effect as setting oops=panic on the kernel command | |
997 | line. | |
a9d9058a | 998 | |
92aef8fb DH |
999 | This feature is useful to ensure that the kernel does not do |
1000 | anything erroneous after an oops which could result in data | |
1001 | corruption or other issues. | |
1002 | ||
1003 | Say N if unsure. | |
1004 | ||
1005 | config PANIC_ON_OOPS_VALUE | |
1006 | int | |
1007 | range 0 1 | |
1008 | default 0 if !PANIC_ON_OOPS | |
1009 | default 1 if PANIC_ON_OOPS | |
1010 | ||
5800dc3c JB |
1011 | config PANIC_TIMEOUT |
1012 | int "panic timeout" | |
1013 | default 0 | |
1014 | help | |
1015 | Set the timeout value (in seconds) until a reboot occurs when the | |
1016 | the kernel panics. If n = 0, then we wait forever. A timeout | |
1017 | value n > 0 will wait n seconds before rebooting, while a timeout | |
1018 | value n < 0 will reboot immediately. | |
1019 | ||
0610c8a8 DH |
1020 | config SCHED_DEBUG |
1021 | bool "Collect scheduler debugging info" | |
1022 | depends on DEBUG_KERNEL && PROC_FS | |
1023 | default y | |
0822ee4a | 1024 | help |
0610c8a8 DH |
1025 | If you say Y here, the /proc/sched_debug file will be provided |
1026 | that can help debug the scheduler. The runtime overhead of this | |
1027 | option is minimal. | |
0822ee4a | 1028 | |
f6db8347 NR |
1029 | config SCHED_INFO |
1030 | bool | |
1031 | default n | |
1032 | ||
0610c8a8 DH |
1033 | config SCHEDSTATS |
1034 | bool "Collect scheduler statistics" | |
1035 | depends on DEBUG_KERNEL && PROC_FS | |
f6db8347 | 1036 | select SCHED_INFO |
0610c8a8 DH |
1037 | help |
1038 | If you say Y here, additional code will be inserted into the | |
1039 | scheduler and related routines to collect statistics about | |
1040 | scheduler behavior and provide them in /proc/schedstat. These | |
1041 | stats may be useful for both tuning and debugging the scheduler | |
1042 | If you aren't debugging the scheduler or trying to tune a specific | |
1043 | application, you can say N to avoid the very slight overhead | |
1044 | this adds. | |
0822ee4a | 1045 | |
0d9e2632 AT |
1046 | config SCHED_STACK_END_CHECK |
1047 | bool "Detect stack corruption on calls to schedule()" | |
1048 | depends on DEBUG_KERNEL | |
1049 | default n | |
1050 | help | |
1051 | This option checks for a stack overrun on calls to schedule(). | |
1052 | If the stack end location is found to be over written always panic as | |
1053 | the content of the corrupted region can no longer be trusted. | |
1054 | This is to ensure no erroneous behaviour occurs which could result in | |
1055 | data corruption or a sporadic crash at a later stage once the region | |
1056 | is examined. The runtime overhead introduced is minimal. | |
1057 | ||
3c17ad19 JS |
1058 | config DEBUG_TIMEKEEPING |
1059 | bool "Enable extra timekeeping sanity checking" | |
1060 | help | |
1061 | This option will enable additional timekeeping sanity checks | |
1062 | which may be helpful when diagnosing issues where timekeeping | |
1063 | problems are suspected. | |
1064 | ||
1065 | This may include checks in the timekeeping hotpaths, so this | |
1066 | option may have a (very small) performance impact to some | |
1067 | workloads. | |
1068 | ||
1069 | If unsure, say N. | |
1070 | ||
1da177e4 LT |
1071 | config DEBUG_PREEMPT |
1072 | bool "Debug preemptible kernel" | |
01deab98 | 1073 | depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT |
1da177e4 LT |
1074 | default y |
1075 | help | |
1076 | If you say Y here then the kernel will use a debug variant of the | |
1077 | commonly used smp_processor_id() function and will print warnings | |
1078 | if kernel code uses it in a preemption-unsafe way. Also, the kernel | |
1079 | will detect preemption count underflows. | |
1080 | ||
9eade16b DH |
1081 | menu "Lock Debugging (spinlocks, mutexes, etc...)" |
1082 | ||
f07cbebb WL |
1083 | config LOCK_DEBUGGING_SUPPORT |
1084 | bool | |
1085 | depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT | |
1086 | default y | |
1087 | ||
19193bca WL |
1088 | config PROVE_LOCKING |
1089 | bool "Lock debugging: prove locking correctness" | |
1090 | depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT | |
1091 | select LOCKDEP | |
1092 | select DEBUG_SPINLOCK | |
1093 | select DEBUG_MUTEXES | |
1094 | select DEBUG_RT_MUTEXES if RT_MUTEXES | |
c71fd893 | 1095 | select DEBUG_RWSEMS |
19193bca WL |
1096 | select DEBUG_WW_MUTEX_SLOWPATH |
1097 | select DEBUG_LOCK_ALLOC | |
1098 | select TRACE_IRQFLAGS | |
1099 | default n | |
1100 | help | |
1101 | This feature enables the kernel to prove that all locking | |
1102 | that occurs in the kernel runtime is mathematically | |
1103 | correct: that under no circumstance could an arbitrary (and | |
1104 | not yet triggered) combination of observed locking | |
1105 | sequences (on an arbitrary number of CPUs, running an | |
1106 | arbitrary number of tasks and interrupt contexts) cause a | |
1107 | deadlock. | |
1108 | ||
1109 | In short, this feature enables the kernel to report locking | |
1110 | related deadlocks before they actually occur. | |
1111 | ||
1112 | The proof does not depend on how hard and complex a | |
1113 | deadlock scenario would be to trigger: how many | |
1114 | participant CPUs, tasks and irq-contexts would be needed | |
1115 | for it to trigger. The proof also does not depend on | |
1116 | timing: if a race and a resulting deadlock is possible | |
1117 | theoretically (no matter how unlikely the race scenario | |
1118 | is), it will be proven so and will immediately be | |
1119 | reported by the kernel (once the event is observed that | |
1120 | makes the deadlock theoretically possible). | |
1121 | ||
1122 | If a deadlock is impossible (i.e. the locking rules, as | |
1123 | observed by the kernel, are mathematically correct), the | |
1124 | kernel reports nothing. | |
1125 | ||
1126 | NOTE: this feature can also be enabled for rwlocks, mutexes | |
1127 | and rwsems - in which case all dependencies between these | |
1128 | different locking variants are observed and mapped too, and | |
1129 | the proof of observed correctness is also maintained for an | |
1130 | arbitrary combination of these separate locking variants. | |
1131 | ||
387b1468 | 1132 | For more details, see Documentation/locking/lockdep-design.rst. |
19193bca WL |
1133 | |
1134 | config LOCK_STAT | |
1135 | bool "Lock usage statistics" | |
1136 | depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT | |
1137 | select LOCKDEP | |
1138 | select DEBUG_SPINLOCK | |
1139 | select DEBUG_MUTEXES | |
1140 | select DEBUG_RT_MUTEXES if RT_MUTEXES | |
1141 | select DEBUG_LOCK_ALLOC | |
1142 | default n | |
1143 | help | |
1144 | This feature enables tracking lock contention points | |
1145 | ||
387b1468 | 1146 | For more details, see Documentation/locking/lockstat.rst |
19193bca WL |
1147 | |
1148 | This also enables lock events required by "perf lock", | |
1149 | subcommand of perf. | |
1150 | If you want to use "perf lock", you also need to turn on | |
1151 | CONFIG_EVENT_TRACING. | |
1152 | ||
1153 | CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. | |
1154 | (CONFIG_LOCKDEP defines "acquire" and "release" events.) | |
1155 | ||
e7eebaf6 IM |
1156 | config DEBUG_RT_MUTEXES |
1157 | bool "RT Mutex debugging, deadlock detection" | |
e7eebaf6 IM |
1158 | depends on DEBUG_KERNEL && RT_MUTEXES |
1159 | help | |
1160 | This allows rt mutex semantics violations and rt mutex related | |
1161 | deadlocks (lockups) to be detected and reported automatically. | |
1162 | ||
1da177e4 | 1163 | config DEBUG_SPINLOCK |
4d9f34ad | 1164 | bool "Spinlock and rw-lock debugging: basic checks" |
1da177e4 | 1165 | depends on DEBUG_KERNEL |
e335e3eb | 1166 | select UNINLINE_SPIN_UNLOCK |
1da177e4 LT |
1167 | help |
1168 | Say Y here and build SMP to catch missing spinlock initialization | |
1169 | and certain other kinds of spinlock errors commonly made. This is | |
1170 | best used in conjunction with the NMI watchdog so that spinlock | |
1171 | deadlocks are also debuggable. | |
1172 | ||
4d9f34ad IM |
1173 | config DEBUG_MUTEXES |
1174 | bool "Mutex debugging: basic checks" | |
1175 | depends on DEBUG_KERNEL | |
1176 | help | |
1177 | This feature allows mutex semantics violations to be detected and | |
1178 | reported. | |
1179 | ||
23010027 DV |
1180 | config DEBUG_WW_MUTEX_SLOWPATH |
1181 | bool "Wait/wound mutex debugging: Slowpath testing" | |
f07cbebb | 1182 | depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT |
23010027 DV |
1183 | select DEBUG_LOCK_ALLOC |
1184 | select DEBUG_SPINLOCK | |
1185 | select DEBUG_MUTEXES | |
1186 | help | |
1187 | This feature enables slowpath testing for w/w mutex users by | |
1188 | injecting additional -EDEADLK wound/backoff cases. Together with | |
1189 | the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this | |
1190 | will test all possible w/w mutex interface abuse with the | |
1191 | exception of simply not acquiring all the required locks. | |
4d692373 RC |
1192 | Note that this feature can introduce significant overhead, so |
1193 | it really should not be enabled in a production or distro kernel, | |
1194 | even a debug kernel. If you are a driver writer, enable it. If | |
1195 | you are a distro, do not. | |
23010027 | 1196 | |
5149cbac WL |
1197 | config DEBUG_RWSEMS |
1198 | bool "RW Semaphore debugging: basic checks" | |
c71fd893 | 1199 | depends on DEBUG_KERNEL |
5149cbac | 1200 | help |
c71fd893 WL |
1201 | This debugging feature allows mismatched rw semaphore locks |
1202 | and unlocks to be detected and reported. | |
5149cbac | 1203 | |
4d9f34ad IM |
1204 | config DEBUG_LOCK_ALLOC |
1205 | bool "Lock debugging: detect incorrect freeing of live locks" | |
f07cbebb | 1206 | depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT |
4d9f34ad IM |
1207 | select DEBUG_SPINLOCK |
1208 | select DEBUG_MUTEXES | |
f5694788 | 1209 | select DEBUG_RT_MUTEXES if RT_MUTEXES |
4d9f34ad IM |
1210 | select LOCKDEP |
1211 | help | |
1212 | This feature will check whether any held lock (spinlock, rwlock, | |
1213 | mutex or rwsem) is incorrectly freed by the kernel, via any of the | |
1214 | memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), | |
1215 | vfree(), etc.), whether a live lock is incorrectly reinitialized via | |
1216 | spin_lock_init()/mutex_init()/etc., or whether there is any lock | |
1217 | held during task exit. | |
1218 | ||
4d9f34ad IM |
1219 | config LOCKDEP |
1220 | bool | |
f07cbebb | 1221 | depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT |
4d9f34ad | 1222 | select STACKTRACE |
f9b58e8c | 1223 | select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86 |
4d9f34ad IM |
1224 | select KALLSYMS |
1225 | select KALLSYMS_ALL | |
1226 | ||
395102db DJ |
1227 | config LOCKDEP_SMALL |
1228 | bool | |
1229 | ||
4d9f34ad IM |
1230 | config DEBUG_LOCKDEP |
1231 | bool "Lock dependency engine debugging" | |
517e7aa5 | 1232 | depends on DEBUG_KERNEL && LOCKDEP |
4d9f34ad IM |
1233 | help |
1234 | If you say Y here, the lock dependency engine will do | |
1235 | additional runtime checks to debug itself, at the price | |
1236 | of more runtime overhead. | |
1237 | ||
d902db1e FW |
1238 | config DEBUG_ATOMIC_SLEEP |
1239 | bool "Sleep inside atomic section checking" | |
e8f7c70f | 1240 | select PREEMPT_COUNT |
1da177e4 | 1241 | depends on DEBUG_KERNEL |
87a4c375 | 1242 | depends on !ARCH_NO_PREEMPT |
1da177e4 LT |
1243 | help |
1244 | If you say Y here, various routines which may sleep will become very | |
d902db1e FW |
1245 | noisy if they are called inside atomic sections: when a spinlock is |
1246 | held, inside an rcu read side critical section, inside preempt disabled | |
1247 | sections, inside an interrupt, etc... | |
1da177e4 | 1248 | |
cae2ed9a IM |
1249 | config DEBUG_LOCKING_API_SELFTESTS |
1250 | bool "Locking API boot-time self-tests" | |
1251 | depends on DEBUG_KERNEL | |
1252 | help | |
1253 | Say Y here if you want the kernel to run a short self-test during | |
1254 | bootup. The self-test checks whether common types of locking bugs | |
1255 | are detected by debugging mechanisms or not. (if you disable | |
1256 | lock debugging then those bugs wont be detected of course.) | |
1257 | The following locking APIs are covered: spinlocks, rwlocks, | |
1258 | mutexes and rwsems. | |
1259 | ||
0af3fe1e PM |
1260 | config LOCK_TORTURE_TEST |
1261 | tristate "torture tests for locking" | |
1262 | depends on DEBUG_KERNEL | |
1263 | select TORTURE_TEST | |
0af3fe1e PM |
1264 | help |
1265 | This option provides a kernel module that runs torture tests | |
1266 | on kernel locking primitives. The kernel module may be built | |
1267 | after the fact on the running kernel to be tested, if desired. | |
1268 | ||
1269 | Say Y here if you want kernel locking-primitive torture tests | |
1270 | to be built into the kernel. | |
1271 | Say M if you want these torture tests to build as a module. | |
1272 | Say N if you are unsure. | |
1273 | ||
f2a5fec1 CW |
1274 | config WW_MUTEX_SELFTEST |
1275 | tristate "Wait/wound mutex selftests" | |
1276 | help | |
1277 | This option provides a kernel module that runs tests on the | |
1278 | on the struct ww_mutex locking API. | |
1279 | ||
1280 | It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction | |
1281 | with this test harness. | |
1282 | ||
1283 | Say M if you want these self tests to build as a module. | |
1284 | Say N if you are unsure. | |
1285 | ||
9eade16b | 1286 | endmenu # lock debugging |
8637c099 | 1287 | |
9eade16b DH |
1288 | config TRACE_IRQFLAGS |
1289 | bool | |
5ca43f6c | 1290 | help |
9eade16b DH |
1291 | Enables hooks to interrupt enabling and disabling for |
1292 | either tracing or lock debugging. | |
5ca43f6c | 1293 | |
8637c099 | 1294 | config STACKTRACE |
0c38e1fe | 1295 | bool "Stack backtrace support" |
8637c099 | 1296 | depends on STACKTRACE_SUPPORT |
0c38e1fe DJ |
1297 | help |
1298 | This option causes the kernel to create a /proc/pid/stack for | |
1299 | every process, showing its current stack trace. | |
1300 | It is also used by various kernel debugging features that require | |
1301 | stack trace generation. | |
5ca43f6c | 1302 | |
eecabf56 TT |
1303 | config WARN_ALL_UNSEEDED_RANDOM |
1304 | bool "Warn for all uses of unseeded randomness" | |
1305 | default n | |
d06bfd19 JD |
1306 | help |
1307 | Some parts of the kernel contain bugs relating to their use of | |
1308 | cryptographically secure random numbers before it's actually possible | |
1309 | to generate those numbers securely. This setting ensures that these | |
1310 | flaws don't go unnoticed, by enabling a message, should this ever | |
1311 | occur. This will allow people with obscure setups to know when things | |
1312 | are going wrong, so that they might contact developers about fixing | |
1313 | it. | |
1314 | ||
eecabf56 TT |
1315 | Unfortunately, on some models of some architectures getting |
1316 | a fully seeded CRNG is extremely difficult, and so this can | |
1317 | result in dmesg getting spammed for a surprisingly long | |
1318 | time. This is really bad from a security perspective, and | |
1319 | so architecture maintainers really need to do what they can | |
1320 | to get the CRNG seeded sooner after the system is booted. | |
4c5d114e | 1321 | However, since users cannot do anything actionable to |
eecabf56 TT |
1322 | address this, by default the kernel will issue only a single |
1323 | warning for the first use of unseeded randomness. | |
1324 | ||
1325 | Say Y here if you want to receive warnings for all uses of | |
1326 | unseeded randomness. This will be of use primarily for | |
4c5d114e | 1327 | those developers interested in improving the security of |
eecabf56 TT |
1328 | Linux kernels running on their architecture (or |
1329 | subarchitecture). | |
d06bfd19 | 1330 | |
1da177e4 LT |
1331 | config DEBUG_KOBJECT |
1332 | bool "kobject debugging" | |
1333 | depends on DEBUG_KERNEL | |
1334 | help | |
1335 | If you say Y here, some extra kobject debugging messages will be sent | |
aca52c39 | 1336 | to the syslog. |
1da177e4 | 1337 | |
c817a67e RK |
1338 | config DEBUG_KOBJECT_RELEASE |
1339 | bool "kobject release debugging" | |
2a999aa0 | 1340 | depends on DEBUG_OBJECTS_TIMERS |
c817a67e RK |
1341 | help |
1342 | kobjects are reference counted objects. This means that their | |
1343 | last reference count put is not predictable, and the kobject can | |
1344 | live on past the point at which a driver decides to drop it's | |
1345 | initial reference to the kobject gained on allocation. An | |
1346 | example of this would be a struct device which has just been | |
1347 | unregistered. | |
1348 | ||
1349 | However, some buggy drivers assume that after such an operation, | |
1350 | the memory backing the kobject can be immediately freed. This | |
1351 | goes completely against the principles of a refcounted object. | |
1352 | ||
1353 | If you say Y here, the kernel will delay the release of kobjects | |
1354 | on the last reference count to improve the visibility of this | |
1355 | kind of kobject release bug. | |
1356 | ||
9b2a60c4 CM |
1357 | config HAVE_DEBUG_BUGVERBOSE |
1358 | bool | |
1359 | ||
1da177e4 | 1360 | config DEBUG_BUGVERBOSE |
6a108a14 | 1361 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT |
9b2a60c4 | 1362 | depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE) |
8420e7ef | 1363 | default y |
1da177e4 LT |
1364 | help |
1365 | Say Y here to make BUG() panics output the file name and line number | |
1366 | of the BUG call as well as the EIP and oops trace. This aids | |
1367 | debugging but costs about 70-100K of memory. | |
1368 | ||
199a9afc DJ |
1369 | config DEBUG_LIST |
1370 | bool "Debug linked list manipulation" | |
4520bcb2 | 1371 | depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION |
199a9afc DJ |
1372 | help |
1373 | Enable this to turn on extended checks in the linked-list | |
1374 | walking routines. | |
1375 | ||
1376 | If unsure, say N. | |
1377 | ||
8e18faea | 1378 | config DEBUG_PLIST |
b8cfff68 DS |
1379 | bool "Debug priority linked list manipulation" |
1380 | depends on DEBUG_KERNEL | |
1381 | help | |
1382 | Enable this to turn on extended checks in the priority-ordered | |
1383 | linked-list (plist) walking routines. This checks the entire | |
1384 | list multiple times during each manipulation. | |
1385 | ||
1386 | If unsure, say N. | |
1387 | ||
d6ec0842 JA |
1388 | config DEBUG_SG |
1389 | bool "Debug SG table operations" | |
1390 | depends on DEBUG_KERNEL | |
1391 | help | |
1392 | Enable this to turn on checks on scatter-gather tables. This can | |
1393 | help find problems with drivers that do not properly initialize | |
1394 | their sg tables. | |
1395 | ||
1396 | If unsure, say N. | |
1397 | ||
1b2439db AV |
1398 | config DEBUG_NOTIFIERS |
1399 | bool "Debug notifier call chains" | |
1400 | depends on DEBUG_KERNEL | |
1401 | help | |
1402 | Enable this to turn on sanity checking for notifier call chains. | |
1403 | This is most useful for kernel developers to make sure that | |
1404 | modules properly unregister themselves from notifier chains. | |
1405 | This is a relatively cheap check but if you care about maximum | |
1406 | performance, say N. | |
1407 | ||
e0e81739 DH |
1408 | config DEBUG_CREDENTIALS |
1409 | bool "Debug credential management" | |
1410 | depends on DEBUG_KERNEL | |
1411 | help | |
1412 | Enable this to turn on some debug checking for credential | |
1413 | management. The additional code keeps track of the number of | |
1414 | pointers from task_structs to any given cred struct, and checks to | |
1415 | see that this number never exceeds the usage count of the cred | |
1416 | struct. | |
1417 | ||
1418 | Furthermore, if SELinux is enabled, this also checks that the | |
1419 | security pointer in the cred struct is never seen to be invalid. | |
1420 | ||
1421 | If unsure, say N. | |
1422 | ||
43a0a2a7 | 1423 | source "kernel/rcu/Kconfig.debug" |
2f03e3ca | 1424 | |
f303fccb TH |
1425 | config DEBUG_WQ_FORCE_RR_CPU |
1426 | bool "Force round-robin CPU selection for unbound work items" | |
1427 | depends on DEBUG_KERNEL | |
1428 | default n | |
1429 | help | |
1430 | Workqueue used to implicitly guarantee that work items queued | |
1431 | without explicit CPU specified are put on the local CPU. This | |
1432 | guarantee is no longer true and while local CPU is still | |
1433 | preferred work items may be put on foreign CPUs. Kernel | |
1434 | parameter "workqueue.debug_force_rr_cpu" is added to force | |
1435 | round-robin CPU selection to flush out usages which depend on the | |
1436 | now broken guarantee. This config option enables the debug | |
1437 | feature by default. When enabled, memory and cache locality will | |
1438 | be impacted. | |
1439 | ||
870d6656 TH |
1440 | config DEBUG_BLOCK_EXT_DEVT |
1441 | bool "Force extended block device numbers and spread them" | |
1442 | depends on DEBUG_KERNEL | |
1443 | depends on BLOCK | |
759f8ca3 | 1444 | default n |
870d6656 | 1445 | help |
0e11e342 TH |
1446 | BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON |
1447 | SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT | |
1448 | YOU ARE DOING. Distros, please enable this and fix whatever | |
1449 | is broken. | |
1450 | ||
870d6656 TH |
1451 | Conventionally, block device numbers are allocated from |
1452 | predetermined contiguous area. However, extended block area | |
1453 | may introduce non-contiguous block device numbers. This | |
1454 | option forces most block device numbers to be allocated from | |
1455 | the extended space and spreads them to discover kernel or | |
1456 | userland code paths which assume predetermined contiguous | |
1457 | device number allocation. | |
1458 | ||
55dc7db7 TH |
1459 | Note that turning on this debug option shuffles all the |
1460 | device numbers for all IDE and SCSI devices including libata | |
1461 | ones, so root partition specified using device number | |
1462 | directly (via rdev or root=MAJ:MIN) won't work anymore. | |
1463 | Textual device names (root=/dev/sdXn) will continue to work. | |
1464 | ||
870d6656 TH |
1465 | Say N if you are unsure. |
1466 | ||
757c989b TG |
1467 | config CPU_HOTPLUG_STATE_CONTROL |
1468 | bool "Enable CPU hotplug state control" | |
1469 | depends on DEBUG_KERNEL | |
1470 | depends on HOTPLUG_CPU | |
1471 | default n | |
1472 | help | |
1473 | Allows to write steps between "offline" and "online" to the CPUs | |
1474 | sysfs target file so states can be stepped granular. This is a debug | |
1475 | option for now as the hotplug machinery cannot be stopped and | |
1476 | restarted at arbitrary points yet. | |
1477 | ||
1478 | Say N if your are unsure. | |
1479 | ||
8d438288 AM |
1480 | config NOTIFIER_ERROR_INJECTION |
1481 | tristate "Notifier error injection" | |
1482 | depends on DEBUG_KERNEL | |
1483 | select DEBUG_FS | |
1484 | help | |
e41e85cc | 1485 | This option provides the ability to inject artificial errors to |
8d438288 AM |
1486 | specified notifier chain callbacks. It is useful to test the error |
1487 | handling of notifier call chain failures. | |
1488 | ||
1489 | Say N if unsure. | |
1490 | ||
048b9c35 AM |
1491 | config PM_NOTIFIER_ERROR_INJECT |
1492 | tristate "PM notifier error injection module" | |
1493 | depends on PM && NOTIFIER_ERROR_INJECTION | |
1494 | default m if PM_DEBUG | |
1495 | help | |
e41e85cc | 1496 | This option provides the ability to inject artificial errors to |
048b9c35 AM |
1497 | PM notifier chain callbacks. It is controlled through debugfs |
1498 | interface /sys/kernel/debug/notifier-error-inject/pm | |
1499 | ||
1500 | If the notifier call chain should be failed with some events | |
1501 | notified, write the error code to "actions/<notifier event>/error". | |
1502 | ||
1503 | Example: Inject PM suspend error (-12 = -ENOMEM) | |
1504 | ||
1505 | # cd /sys/kernel/debug/notifier-error-inject/pm/ | |
1506 | # echo -12 > actions/PM_SUSPEND_PREPARE/error | |
1507 | # echo mem > /sys/power/state | |
1508 | bash: echo: write error: Cannot allocate memory | |
1509 | ||
1510 | To compile this code as a module, choose M here: the module will | |
1511 | be called pm-notifier-error-inject. | |
1512 | ||
1513 | If unsure, say N. | |
1514 | ||
d526e85f BH |
1515 | config OF_RECONFIG_NOTIFIER_ERROR_INJECT |
1516 | tristate "OF reconfig notifier error injection module" | |
1517 | depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION | |
08dfb4dd | 1518 | help |
e41e85cc | 1519 | This option provides the ability to inject artificial errors to |
d526e85f | 1520 | OF reconfig notifier chain callbacks. It is controlled |
08dfb4dd | 1521 | through debugfs interface under |
d526e85f | 1522 | /sys/kernel/debug/notifier-error-inject/OF-reconfig/ |
08dfb4dd AM |
1523 | |
1524 | If the notifier call chain should be failed with some events | |
1525 | notified, write the error code to "actions/<notifier event>/error". | |
1526 | ||
1527 | To compile this code as a module, choose M here: the module will | |
e12a95f4 | 1528 | be called of-reconfig-notifier-error-inject. |
08dfb4dd AM |
1529 | |
1530 | If unsure, say N. | |
1531 | ||
02fff96a NA |
1532 | config NETDEV_NOTIFIER_ERROR_INJECT |
1533 | tristate "Netdev notifier error injection module" | |
1534 | depends on NET && NOTIFIER_ERROR_INJECTION | |
1535 | help | |
1536 | This option provides the ability to inject artificial errors to | |
1537 | netdevice notifier chain callbacks. It is controlled through debugfs | |
1538 | interface /sys/kernel/debug/notifier-error-inject/netdev | |
1539 | ||
1540 | If the notifier call chain should be failed with some events | |
1541 | notified, write the error code to "actions/<notifier event>/error". | |
1542 | ||
1543 | Example: Inject netdevice mtu change error (-22 = -EINVAL) | |
1544 | ||
1545 | # cd /sys/kernel/debug/notifier-error-inject/netdev | |
1546 | # echo -22 > actions/NETDEV_CHANGEMTU/error | |
1547 | # ip link set eth0 mtu 1024 | |
1548 | RTNETLINK answers: Invalid argument | |
1549 | ||
1550 | To compile this code as a module, choose M here: the module will | |
1551 | be called netdev-notifier-error-inject. | |
1552 | ||
1553 | If unsure, say N. | |
1554 | ||
f1b4bd06 MP |
1555 | config FUNCTION_ERROR_INJECTION |
1556 | def_bool y | |
1557 | depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES | |
1558 | ||
6ff1cb35 | 1559 | config FAULT_INJECTION |
1ab8509a AM |
1560 | bool "Fault-injection framework" |
1561 | depends on DEBUG_KERNEL | |
329409ae AM |
1562 | help |
1563 | Provide fault-injection framework. | |
1564 | For more details, see Documentation/fault-injection/. | |
6ff1cb35 | 1565 | |
8a8b6502 | 1566 | config FAILSLAB |
1ab8509a AM |
1567 | bool "Fault-injection capability for kmalloc" |
1568 | depends on FAULT_INJECTION | |
773ff60e | 1569 | depends on SLAB || SLUB |
8a8b6502 | 1570 | help |
1ab8509a | 1571 | Provide fault-injection capability for kmalloc. |
8a8b6502 | 1572 | |
933e312e AM |
1573 | config FAIL_PAGE_ALLOC |
1574 | bool "Fault-injection capabilitiy for alloc_pages()" | |
1ab8509a | 1575 | depends on FAULT_INJECTION |
933e312e | 1576 | help |
1ab8509a | 1577 | Provide fault-injection capability for alloc_pages(). |
933e312e | 1578 | |
c17bb495 | 1579 | config FAIL_MAKE_REQUEST |
86327d19 | 1580 | bool "Fault-injection capability for disk IO" |
581d4e28 | 1581 | depends on FAULT_INJECTION && BLOCK |
c17bb495 | 1582 | help |
1ab8509a | 1583 | Provide fault-injection capability for disk IO. |
c17bb495 | 1584 | |
581d4e28 | 1585 | config FAIL_IO_TIMEOUT |
f4d01439 | 1586 | bool "Fault-injection capability for faking disk interrupts" |
581d4e28 JA |
1587 | depends on FAULT_INJECTION && BLOCK |
1588 | help | |
1589 | Provide fault-injection capability on end IO handling. This | |
1590 | will make the block layer "forget" an interrupt as configured, | |
1591 | thus exercising the error handling. | |
1592 | ||
1593 | Only works with drivers that use the generic timeout handling, | |
1594 | for others it wont do anything. | |
1595 | ||
ab51fbab DB |
1596 | config FAIL_FUTEX |
1597 | bool "Fault-injection capability for futexes" | |
1598 | select DEBUG_FS | |
1599 | depends on FAULT_INJECTION && FUTEX | |
1600 | help | |
1601 | Provide fault-injection capability for futexes. | |
1602 | ||
f1b4bd06 MP |
1603 | config FAULT_INJECTION_DEBUG_FS |
1604 | bool "Debugfs entries for fault-injection capabilities" | |
1605 | depends on FAULT_INJECTION && SYSFS && DEBUG_FS | |
1606 | help | |
1607 | Enable configuration of fault-injection capabilities via debugfs. | |
1608 | ||
4b1a29a7 MH |
1609 | config FAIL_FUNCTION |
1610 | bool "Fault-injection capability for functions" | |
1611 | depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION | |
1612 | help | |
1613 | Provide function-based fault-injection capability. | |
1614 | This will allow you to override a specific function with a return | |
1615 | with given return value. As a result, function caller will see | |
1616 | an error value and have to handle it. This is useful to test the | |
1617 | error handling in various subsystems. | |
1618 | ||
f1b4bd06 MP |
1619 | config FAIL_MMC_REQUEST |
1620 | bool "Fault-injection capability for MMC IO" | |
1621 | depends on FAULT_INJECTION_DEBUG_FS && MMC | |
6ff1cb35 | 1622 | help |
f1b4bd06 MP |
1623 | Provide fault-injection capability for MMC IO. |
1624 | This will make the mmc core return data errors. This is | |
1625 | useful to test the error handling in the mmc block device | |
1626 | and to test how the mmc host driver handles retries from | |
1627 | the block device. | |
1df49008 AM |
1628 | |
1629 | config FAULT_INJECTION_STACKTRACE_FILTER | |
1630 | bool "stacktrace filter for fault-injection capabilities" | |
1631 | depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT | |
6d690dca | 1632 | depends on !X86_64 |
1df49008 | 1633 | select STACKTRACE |
f9b58e8c | 1634 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86 |
1df49008 AM |
1635 | help |
1636 | Provide stacktrace filter for fault-injection capabilities | |
267c4025 | 1637 | |
9745512c AV |
1638 | config LATENCYTOP |
1639 | bool "Latency measuring infrastructure" | |
625fdcaa RD |
1640 | depends on DEBUG_KERNEL |
1641 | depends on STACKTRACE_SUPPORT | |
1642 | depends on PROC_FS | |
f9b58e8c | 1643 | select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86 |
9745512c AV |
1644 | select KALLSYMS |
1645 | select KALLSYMS_ALL | |
1646 | select STACKTRACE | |
1647 | select SCHEDSTATS | |
1648 | select SCHED_DEBUG | |
9745512c AV |
1649 | help |
1650 | Enable this option if you want to use the LatencyTOP tool | |
1651 | to find out which userspace is blocking on what kernel operations. | |
1652 | ||
8636a1f9 | 1653 | source "kernel/trace/Kconfig" |
16444a8a | 1654 | |
cc3fa840 RD |
1655 | config PROVIDE_OHCI1394_DMA_INIT |
1656 | bool "Remote debugging over FireWire early on boot" | |
1657 | depends on PCI && X86 | |
1658 | help | |
1659 | If you want to debug problems which hang or crash the kernel early | |
1660 | on boot and the crashing machine has a FireWire port, you can use | |
1661 | this feature to remotely access the memory of the crashed machine | |
1662 | over FireWire. This employs remote DMA as part of the OHCI1394 | |
1663 | specification which is now the standard for FireWire controllers. | |
1664 | ||
1665 | With remote DMA, you can monitor the printk buffer remotely using | |
1666 | firescope and access all memory below 4GB using fireproxy from gdb. | |
1667 | Even controlling a kernel debugger is possible using remote DMA. | |
1668 | ||
1669 | Usage: | |
1670 | ||
1671 | If ohci1394_dma=early is used as boot parameter, it will initialize | |
1672 | all OHCI1394 controllers which are found in the PCI config space. | |
1673 | ||
1674 | As all changes to the FireWire bus such as enabling and disabling | |
1675 | devices cause a bus reset and thereby disable remote DMA for all | |
1676 | devices, be sure to have the cable plugged and FireWire enabled on | |
1677 | the debugging host before booting the debug target for debugging. | |
1678 | ||
1679 | This code (~1k) is freed after boot. By then, the firewire stack | |
1680 | in charge of the OHCI-1394 controllers should be used instead. | |
1681 | ||
1682 | See Documentation/debugging-via-ohci1394.txt for more information. | |
1683 | ||
d3deafaa VL |
1684 | menuconfig RUNTIME_TESTING_MENU |
1685 | bool "Runtime Testing" | |
908009e8 | 1686 | def_bool y |
d3deafaa VL |
1687 | |
1688 | if RUNTIME_TESTING_MENU | |
881c5149 DH |
1689 | |
1690 | config LKDTM | |
1691 | tristate "Linux Kernel Dump Test Tool Module" | |
1692 | depends on DEBUG_FS | |
881c5149 DH |
1693 | help |
1694 | This module enables testing of the different dumping mechanisms by | |
1695 | inducing system failures at predefined crash points. | |
1696 | If you don't need it: say N | |
1697 | Choose M here to compile this code as a module. The module will be | |
1698 | called lkdtm. | |
1699 | ||
1700 | Documentation on how to use the module can be found in | |
10ffebbe | 1701 | Documentation/fault-injection/provoke-crashes.rst |
881c5149 DH |
1702 | |
1703 | config TEST_LIST_SORT | |
e327fd7c GU |
1704 | tristate "Linked list sorting test" |
1705 | depends on DEBUG_KERNEL || m | |
881c5149 DH |
1706 | help |
1707 | Enable this to turn on 'list_sort()' function test. This test is | |
e327fd7c GU |
1708 | executed only once during system boot (so affects only boot time), |
1709 | or at module load time. | |
881c5149 DH |
1710 | |
1711 | If unsure, say N. | |
1712 | ||
c5adae95 | 1713 | config TEST_SORT |
5c4e6798 GU |
1714 | tristate "Array-based sort test" |
1715 | depends on DEBUG_KERNEL || m | |
c5adae95 | 1716 | help |
5c4e6798 GU |
1717 | This option enables the self-test function of 'sort()' at boot, |
1718 | or at module load time. | |
c5adae95 KF |
1719 | |
1720 | If unsure, say N. | |
1721 | ||
881c5149 DH |
1722 | config KPROBES_SANITY_TEST |
1723 | bool "Kprobes sanity tests" | |
1724 | depends on DEBUG_KERNEL | |
1725 | depends on KPROBES | |
881c5149 DH |
1726 | help |
1727 | This option provides for testing basic kprobes functionality on | |
5a6cf77f | 1728 | boot. Samples of kprobe and kretprobe are inserted and |
881c5149 DH |
1729 | verified for functionality. |
1730 | ||
1731 | Say N if you are unsure. | |
1732 | ||
1733 | config BACKTRACE_SELF_TEST | |
1734 | tristate "Self test for the backtrace code" | |
1735 | depends on DEBUG_KERNEL | |
881c5149 DH |
1736 | help |
1737 | This option provides a kernel module that can be used to test | |
1738 | the kernel stack backtrace code. This option is not useful | |
1739 | for distributions or general kernels, but only for kernel | |
1740 | developers working on architecture code. | |
1741 | ||
1742 | Note that if you want to also test saved backtraces, you will | |
1743 | have to enable STACKTRACE as well. | |
1744 | ||
1745 | Say N if you are unsure. | |
1746 | ||
910a742d ML |
1747 | config RBTREE_TEST |
1748 | tristate "Red-Black tree test" | |
7c993e11 | 1749 | depends on DEBUG_KERNEL |
910a742d ML |
1750 | help |
1751 | A benchmark measuring the performance of the rbtree library. | |
1752 | Also includes rbtree invariant checks. | |
1753 | ||
4b4f3acc FB |
1754 | config REED_SOLOMON_TEST |
1755 | tristate "Reed-Solomon library test" | |
1756 | depends on DEBUG_KERNEL || m | |
1757 | select REED_SOLOMON | |
1758 | select REED_SOLOMON_ENC16 | |
1759 | select REED_SOLOMON_DEC16 | |
1760 | help | |
1761 | This option enables the self-test function of rslib at boot, | |
1762 | or at module load time. | |
1763 | ||
1764 | If unsure, say N. | |
1765 | ||
fff3fd8a ML |
1766 | config INTERVAL_TREE_TEST |
1767 | tristate "Interval tree test" | |
0f789b67 | 1768 | depends on DEBUG_KERNEL |
a88cc108 | 1769 | select INTERVAL_TREE |
fff3fd8a ML |
1770 | help |
1771 | A benchmark measuring the performance of the interval tree library | |
1772 | ||
623fd807 GT |
1773 | config PERCPU_TEST |
1774 | tristate "Per cpu operations test" | |
1775 | depends on m && DEBUG_KERNEL | |
1776 | help | |
1777 | Enable this option to build test module which validates per-cpu | |
1778 | operations. | |
1779 | ||
1780 | If unsure, say N. | |
1781 | ||
881c5149 | 1782 | config ATOMIC64_SELFTEST |
55ded955 | 1783 | tristate "Perform an atomic64_t self-test" |
881c5149 | 1784 | help |
55ded955 GU |
1785 | Enable this option to test the atomic64_t functions at boot or |
1786 | at module load time. | |
881c5149 DH |
1787 | |
1788 | If unsure, say N. | |
1789 | ||
1790 | config ASYNC_RAID6_TEST | |
1791 | tristate "Self test for hardware accelerated raid6 recovery" | |
1792 | depends on ASYNC_RAID6_RECOV | |
1793 | select ASYNC_MEMCPY | |
1794 | ---help--- | |
1795 | This is a one-shot self test that permutes through the | |
1796 | recovery of all the possible two disk failure scenarios for a | |
1797 | N-disk array. Recovery is performed with the asynchronous | |
1798 | raid6 recovery routines, and will optionally use an offload | |
1799 | engine if one is available. | |
1800 | ||
1801 | If unsure, say N. | |
1802 | ||
64d1d77a AS |
1803 | config TEST_HEXDUMP |
1804 | tristate "Test functions located in the hexdump module at runtime" | |
1805 | ||
881c5149 DH |
1806 | config TEST_STRING_HELPERS |
1807 | tristate "Test functions located in the string_helpers module at runtime" | |
1808 | ||
0b0600c8 TH |
1809 | config TEST_STRSCPY |
1810 | tristate "Test strscpy*() family of functions at runtime" | |
1811 | ||
881c5149 DH |
1812 | config TEST_KSTRTOX |
1813 | tristate "Test kstrto*() family of functions at runtime" | |
1814 | ||
707cc728 RV |
1815 | config TEST_PRINTF |
1816 | tristate "Test printf() family of functions at runtime" | |
1817 | ||
5fd003f5 DD |
1818 | config TEST_BITMAP |
1819 | tristate "Test bitmap_*() family of functions at runtime" | |
5fd003f5 DD |
1820 | help |
1821 | Enable this option to test the bitmap functions at boot. | |
1822 | ||
1823 | If unsure, say N. | |
1824 | ||
0e2dc70e JB |
1825 | config TEST_BITFIELD |
1826 | tristate "Test bitfield functions at runtime" | |
1827 | help | |
1828 | Enable this option to test the bitfield functions at boot. | |
1829 | ||
1830 | If unsure, say N. | |
1831 | ||
cfaff0e5 AS |
1832 | config TEST_UUID |
1833 | tristate "Test functions located in the uuid module at runtime" | |
1834 | ||
ad3d6c72 MW |
1835 | config TEST_XARRAY |
1836 | tristate "Test the XArray code at runtime" | |
1837 | ||
455a35a6 RV |
1838 | config TEST_OVERFLOW |
1839 | tristate "Test check_*_overflow() functions at runtime" | |
1840 | ||
7e1e7763 | 1841 | config TEST_RHASHTABLE |
9d6dbe1b | 1842 | tristate "Perform selftest on resizable hash table" |
7e1e7763 TG |
1843 | help |
1844 | Enable this option to test the rhashtable functions at boot. | |
1845 | ||
1846 | If unsure, say N. | |
1847 | ||
468a9428 GS |
1848 | config TEST_HASH |
1849 | tristate "Perform selftest on hash functions" | |
468a9428 | 1850 | help |
2c956a60 JD |
1851 | Enable this option to test the kernel's integer (<linux/hash.h>), |
1852 | string (<linux/stringhash.h>), and siphash (<linux/siphash.h>) | |
1853 | hash functions on boot (or module load). | |
468a9428 GS |
1854 | |
1855 | This is intended to help people writing architecture-specific | |
1856 | optimized versions. If unsure, say N. | |
1857 | ||
8ab8ba38 MW |
1858 | config TEST_IDA |
1859 | tristate "Perform selftest on IDA functions" | |
1860 | ||
44091d29 JP |
1861 | config TEST_PARMAN |
1862 | tristate "Perform selftest on priority array manager" | |
44091d29 JP |
1863 | depends on PARMAN |
1864 | help | |
1865 | Enable this option to test priority array manager on boot | |
1866 | (or module load). | |
1867 | ||
1868 | If unsure, say N. | |
1869 | ||
6aed82de DL |
1870 | config TEST_IRQ_TIMINGS |
1871 | bool "IRQ timings selftest" | |
1872 | depends on IRQ_TIMINGS | |
1873 | help | |
1874 | Enable this option to test the irq timings code on boot. | |
1875 | ||
1876 | If unsure, say N. | |
1877 | ||
8a6f0b47 | 1878 | config TEST_LKM |
93e9ef83 | 1879 | tristate "Test module loading with 'hello world' module" |
93e9ef83 KC |
1880 | depends on m |
1881 | help | |
1882 | This builds the "test_module" module that emits "Hello, world" | |
1883 | on printk when loaded. It is designed to be used for basic | |
1884 | evaluation of the module loading subsystem (for example when | |
1885 | validating module verification). It lacks any extra dependencies, | |
1886 | and will not normally be loaded by the system unless explicitly | |
1887 | requested by name. | |
1888 | ||
1889 | If unsure, say N. | |
1890 | ||
3f21a6b7 URS |
1891 | config TEST_VMALLOC |
1892 | tristate "Test module for stress/performance analysis of vmalloc allocator" | |
1893 | default n | |
1894 | depends on MMU | |
1895 | depends on m | |
1896 | help | |
1897 | This builds the "test_vmalloc" module that should be used for | |
1898 | stress and performance analysis. So, any new change for vmalloc | |
1899 | subsystem can be evaluated from performance and stability point | |
1900 | of view. | |
1901 | ||
1902 | If unsure, say N. | |
1903 | ||
3e2a4c18 KC |
1904 | config TEST_USER_COPY |
1905 | tristate "Test user/kernel boundary protections" | |
3e2a4c18 KC |
1906 | depends on m |
1907 | help | |
1908 | This builds the "test_user_copy" module that runs sanity checks | |
1909 | on the copy_to/from_user infrastructure, making sure basic | |
1910 | user/kernel boundary testing is working. If it fails to load, | |
1911 | a regression has been detected in the user/kernel memory boundary | |
1912 | protections. | |
1913 | ||
1914 | If unsure, say N. | |
1915 | ||
64a8946b AS |
1916 | config TEST_BPF |
1917 | tristate "Test BPF filter functionality" | |
98920ba6 | 1918 | depends on m && NET |
64a8946b AS |
1919 | help |
1920 | This builds the "test_bpf" module that runs various test vectors | |
1921 | against the BPF interpreter or BPF JIT compiler depending on the | |
1922 | current setting. This is in particular useful for BPF JIT compiler | |
1923 | development, but also to run regression tests against changes in | |
3c731eba AS |
1924 | the interpreter code. It also enables test stubs for eBPF maps and |
1925 | verifier used by user space verifier testsuite. | |
64a8946b AS |
1926 | |
1927 | If unsure, say N. | |
1928 | ||
509e56b3 MB |
1929 | config TEST_BLACKHOLE_DEV |
1930 | tristate "Test blackhole netdev functionality" | |
1931 | depends on m && NET | |
1932 | help | |
1933 | This builds the "test_blackhole_dev" module that validates the | |
1934 | data path through this blackhole netdev. | |
1935 | ||
1936 | If unsure, say N. | |
1937 | ||
dceeb3e7 | 1938 | config FIND_BIT_BENCHMARK |
4441fca0 | 1939 | tristate "Test find_bit functions" |
4441fca0 YN |
1940 | help |
1941 | This builds the "test_find_bit" module that measure find_*_bit() | |
1942 | functions performance. | |
1943 | ||
1944 | If unsure, say N. | |
1945 | ||
0a8adf58 KC |
1946 | config TEST_FIRMWARE |
1947 | tristate "Test firmware loading via userspace interface" | |
0a8adf58 KC |
1948 | depends on FW_LOADER |
1949 | help | |
1950 | This builds the "test_firmware" module that creates a userspace | |
1951 | interface for testing firmware loading. This can be used to | |
1952 | control the triggering of firmware loading without needing an | |
1953 | actual firmware-using device. The contents can be rechecked by | |
1954 | userspace. | |
1955 | ||
1956 | If unsure, say N. | |
1957 | ||
9308f2f9 LR |
1958 | config TEST_SYSCTL |
1959 | tristate "sysctl test driver" | |
9308f2f9 LR |
1960 | depends on PROC_SYSCTL |
1961 | help | |
1962 | This builds the "test_sysctl" module. This driver enables to test the | |
1963 | proc sysctl interfaces available to drivers safely without affecting | |
1964 | production knobs which might alter system functionality. | |
1965 | ||
1966 | If unsure, say N. | |
1967 | ||
e704f93a DR |
1968 | config TEST_UDELAY |
1969 | tristate "udelay test driver" | |
e704f93a DR |
1970 | help |
1971 | This builds the "udelay_test" module that helps to make sure | |
1972 | that udelay() is working properly. | |
1973 | ||
1974 | If unsure, say N. | |
1975 | ||
2bf9e0ab IM |
1976 | config TEST_STATIC_KEYS |
1977 | tristate "Test static keys" | |
579e1acb JB |
1978 | depends on m |
1979 | help | |
2bf9e0ab | 1980 | Test the static key interfaces. |
579e1acb JB |
1981 | |
1982 | If unsure, say N. | |
1983 | ||
d9c6a72d LR |
1984 | config TEST_KMOD |
1985 | tristate "kmod stress tester" | |
d9c6a72d | 1986 | depends on m |
d9c6a72d | 1987 | depends on NETDEVICES && NET_CORE && INET # for TUN |
ae3d6a32 | 1988 | depends on BLOCK |
d9c6a72d LR |
1989 | select TEST_LKM |
1990 | select XFS_FS | |
1991 | select TUN | |
1992 | select BTRFS_FS | |
1993 | help | |
1994 | Test the kernel's module loading mechanism: kmod. kmod implements | |
1995 | support to load modules using the Linux kernel's usermode helper. | |
1996 | This test provides a series of tests against kmod. | |
1997 | ||
1998 | Although technically you can either build test_kmod as a module or | |
1999 | into the kernel we disallow building it into the kernel since | |
2000 | it stress tests request_module() and this will very likely cause | |
2001 | some issues by taking over precious threads available from other | |
2002 | module load requests, ultimately this could be fatal. | |
2003 | ||
2004 | To run tests run: | |
2005 | ||
2006 | tools/testing/selftests/kmod/kmod.sh --help | |
2007 | ||
2008 | If unsure, say N. | |
2009 | ||
e4dace36 FF |
2010 | config TEST_DEBUG_VIRTUAL |
2011 | tristate "Test CONFIG_DEBUG_VIRTUAL feature" | |
2012 | depends on DEBUG_VIRTUAL | |
2013 | help | |
2014 | Test the kernel's ability to detect incorrect calls to | |
2015 | virt_to_phys() done against the non-linear part of the | |
2016 | kernel's virtual address map. | |
2017 | ||
2018 | If unsure, say N. | |
2019 | ||
ce76d938 AS |
2020 | config TEST_MEMCAT_P |
2021 | tristate "Test memcat_p() helper function" | |
2022 | help | |
2023 | Test the memcat_p() helper for correctly merging two | |
2024 | pointer arrays together. | |
2025 | ||
2026 | If unsure, say N. | |
2027 | ||
a2818ee4 JL |
2028 | config TEST_LIVEPATCH |
2029 | tristate "Test livepatching" | |
2030 | default n | |
bae05437 | 2031 | depends on DYNAMIC_DEBUG |
a2818ee4 JL |
2032 | depends on LIVEPATCH |
2033 | depends on m | |
2034 | help | |
2035 | Test kernel livepatching features for correctness. The tests will | |
2036 | load test modules that will be livepatched in various scenarios. | |
2037 | ||
2038 | To run all the livepatching tests: | |
2039 | ||
2040 | make -C tools/testing/selftests TARGETS=livepatch run_tests | |
2041 | ||
2042 | Alternatively, individual tests may be invoked: | |
2043 | ||
2044 | tools/testing/selftests/livepatch/test-callbacks.sh | |
2045 | tools/testing/selftests/livepatch/test-livepatch.sh | |
2046 | tools/testing/selftests/livepatch/test-shadow-vars.sh | |
2047 | ||
2048 | If unsure, say N. | |
2049 | ||
0a020d41 JP |
2050 | config TEST_OBJAGG |
2051 | tristate "Perform selftest on object aggreration manager" | |
2052 | default n | |
2053 | depends on OBJAGG | |
2054 | help | |
2055 | Enable this option to test object aggregation manager on boot | |
2056 | (or module load). | |
2057 | ||
0a020d41 | 2058 | |
50ceaa95 KC |
2059 | config TEST_STACKINIT |
2060 | tristate "Test level of stack variable initialization" | |
2061 | help | |
2062 | Test if the kernel is zero-initializing stack variables and | |
2063 | padding. Coverage is controlled by compiler flags, | |
2064 | CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, | |
2065 | or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. | |
2066 | ||
2067 | If unsure, say N. | |
2068 | ||
5015a300 AP |
2069 | config TEST_MEMINIT |
2070 | tristate "Test heap/page initialization" | |
2071 | help | |
2072 | Test if the kernel is zero-initializing heap and page allocations. | |
2073 | This can be useful to test init_on_alloc and init_on_free features. | |
2074 | ||
2075 | If unsure, say N. | |
2076 | ||
d3deafaa | 2077 | endif # RUNTIME_TESTING_MENU |
cc3fa840 RD |
2078 | |
2079 | config MEMTEST | |
2080 | bool "Memtest" | |
cc3fa840 RD |
2081 | ---help--- |
2082 | This option adds a kernel parameter 'memtest', which allows memtest | |
2083 | to be set. | |
2084 | memtest=0, mean disabled; -- default | |
2085 | memtest=1, mean do 1 test pattern; | |
2086 | ... | |
2087 | memtest=17, mean do 17 test patterns. | |
2088 | If you are unsure how to answer this question, answer N. | |
2089 | ||
2090 | config BUG_ON_DATA_CORRUPTION | |
2091 | bool "Trigger a BUG when data corruption is detected" | |
2092 | select DEBUG_LIST | |
2093 | help | |
2094 | Select this option if the kernel should BUG when it encounters | |
2095 | data corruption in kernel memory structures when they get checked | |
2096 | for validity. | |
2097 | ||
2098 | If unsure, say N. | |
e4dace36 | 2099 | |
267c4025 | 2100 | source "samples/Kconfig" |
dc7d5527 JW |
2101 | |
2102 | source "lib/Kconfig.kgdb" | |
0a4af3b0 | 2103 | |
c6d30853 AR |
2104 | source "lib/Kconfig.ubsan" |
2105 | ||
21266be9 DW |
2106 | config ARCH_HAS_DEVMEM_IS_ALLOWED |
2107 | bool | |
2108 | ||
2109 | config STRICT_DEVMEM | |
2110 | bool "Filter access to /dev/mem" | |
6b2a65c7 | 2111 | depends on MMU && DEVMEM |
21266be9 | 2112 | depends on ARCH_HAS_DEVMEM_IS_ALLOWED |
a687a533 | 2113 | default y if PPC || X86 || ARM64 |
21266be9 DW |
2114 | ---help--- |
2115 | If this option is disabled, you allow userspace (root) access to all | |
2116 | of memory, including kernel and userspace memory. Accidental | |
2117 | access to this is obviously disastrous, but specific access can | |
2118 | be used by people debugging the kernel. Note that with PAT support | |
2119 | enabled, even in this case there are restrictions on /dev/mem | |
2120 | use due to the cache aliasing requirements. | |
2121 | ||
90a545e9 DW |
2122 | If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem |
2123 | file only allows userspace access to PCI space and the BIOS code and | |
2124 | data regions. This is sufficient for dosemu and X and all common | |
2125 | users of /dev/mem. | |
2126 | ||
2127 | If in doubt, say Y. | |
2128 | ||
2129 | config IO_STRICT_DEVMEM | |
2130 | bool "Filter I/O access to /dev/mem" | |
2131 | depends on STRICT_DEVMEM | |
90a545e9 DW |
2132 | ---help--- |
2133 | If this option is disabled, you allow userspace (root) access to all | |
2134 | io-memory regardless of whether a driver is actively using that | |
2135 | range. Accidental access to this is obviously disastrous, but | |
2136 | specific access can be used by people debugging kernel drivers. | |
2137 | ||
21266be9 | 2138 | If this option is switched on, the /dev/mem file only allows |
90a545e9 DW |
2139 | userspace access to *idle* io-memory ranges (see /proc/iomem) This |
2140 | may break traditional users of /dev/mem (dosemu, legacy X, etc...) | |
2141 | if the driver using a given range cannot be disabled. | |
21266be9 DW |
2142 | |
2143 | If in doubt, say Y. | |
06ec64b8 CH |
2144 | |
2145 | source "arch/$(SRCARCH)/Kconfig.debug" | |
2146 | ||
2147 | endmenu # Kernel hacking |