Merge tag 'pull-tmpfile' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
[linux-block.git] / lib / Kconfig.debug
CommitLineData
ec8f24b7 1# SPDX-License-Identifier: GPL-2.0-only
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2menu "Kernel hacking"
3
604ff0dc 4menu "printk and dmesg options"
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5
6config PRINTK_TIME
7 bool "Show timing information on printks"
d3b8b6e5 8 depends on PRINTK
1da177e4 9 help
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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
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21config 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
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38config STACKTRACE_BUILD_ID
39 bool "Show build ID information in stacktraces"
40 depends on PRINTK
41 help
42 Selecting this option adds build ID information for symbols in
43 stacktraces printed with the printk format '%p[SR]b'.
44
45 This option is intended for distros where debuginfo is not easily
46 accessible but can be downloaded given the build ID of the vmlinux or
47 kernel module where the function is located.
48
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49config CONSOLE_LOGLEVEL_DEFAULT
50 int "Default console loglevel (1-15)"
51 range 1 15
52 default "7"
53 help
54 Default loglevel to determine what will be printed on the console.
55
56 Setting a default here is equivalent to passing in loglevel=<x> in
57 the kernel bootargs. loglevel=<x> continues to override whatever
58 value is specified here as well.
59
50f4d9bd 60 Note: This does not affect the log level of un-prefixed printk()
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61 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
62 option.
63
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64config CONSOLE_LOGLEVEL_QUIET
65 int "quiet console loglevel (1-15)"
66 range 1 15
67 default "4"
68 help
69 loglevel to use when "quiet" is passed on the kernel commandline.
70
71 When "quiet" is passed on the kernel commandline this loglevel
72 will be used as the loglevel. IOW passing "quiet" will be the
73 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
74
42a9dc0b 75config MESSAGE_LOGLEVEL_DEFAULT
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76 int "Default message log level (1-7)"
77 range 1 7
78 default "4"
79 help
80 Default log level for printk statements with no specified priority.
81
82 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83 that are auditing their logs closely may want to set it to a lower
84 priority.
85
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86 Note: This does not affect what message level gets printed on the console
87 by default. To change that, use loglevel=<x> in the kernel bootargs,
88 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
89
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90config BOOT_PRINTK_DELAY
91 bool "Delay each boot printk message by N milliseconds"
92 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
93 help
94 This build option allows you to read kernel boot messages
95 by inserting a short delay after each one. The delay is
96 specified in milliseconds on the kernel command line,
97 using "boot_delay=N".
98
99 It is likely that you would also need to use "lpj=M" to preset
100 the "loops per jiffie" value.
101 See a previous boot log for the "lpj" value to use for your
102 system, and then set "lpj=M" before setting "boot_delay=N".
103 NOTE: Using this option may adversely affect SMP systems.
104 I.e., processors other than the first one may not boot up.
105 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106 what it believes to be lockup conditions.
107
108config DYNAMIC_DEBUG
109 bool "Enable dynamic printk() support"
110 default n
111 depends on PRINTK
239a5791 112 depends on (DEBUG_FS || PROC_FS)
ceabef7d 113 select DYNAMIC_DEBUG_CORE
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114 help
115
116 Compiles debug level messages into the kernel, which would not
117 otherwise be available at runtime. These messages can then be
118 enabled/disabled based on various levels of scope - per source file,
119 function, module, format string, and line number. This mechanism
120 implicitly compiles in all pr_debug() and dev_dbg() calls, which
121 enlarges the kernel text size by about 2%.
122
123 If a source file is compiled with DEBUG flag set, any
124 pr_debug() calls in it are enabled by default, but can be
125 disabled at runtime as below. Note that DEBUG flag is
126 turned on by many CONFIG_*DEBUG* options.
127
128 Usage:
129
130 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
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131 which is contained in the 'debugfs' filesystem or procfs.
132 Thus, the debugfs or procfs filesystem must first be mounted before
133 making use of this feature.
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134 We refer the control file as: <debugfs>/dynamic_debug/control. This
135 file contains a list of the debug statements that can be enabled. The
136 format for each line of the file is:
137
138 filename:lineno [module]function flags format
139
140 filename : source file of the debug statement
141 lineno : line number of the debug statement
142 module : module that contains the debug statement
143 function : function that contains the debug statement
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144 flags : '=p' means the line is turned 'on' for printing
145 format : the format used for the debug statement
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146
147 From a live system:
148
149 nullarbor:~ # cat <debugfs>/dynamic_debug/control
150 # filename:lineno [module]function flags format
151 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154
155 Example usage:
156
157 // enable the message at line 1603 of file svcsock.c
158 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159 <debugfs>/dynamic_debug/control
160
161 // enable all the messages in file svcsock.c
162 nullarbor:~ # echo -n 'file svcsock.c +p' >
163 <debugfs>/dynamic_debug/control
164
165 // enable all the messages in the NFS server module
166 nullarbor:~ # echo -n 'module nfsd +p' >
167 <debugfs>/dynamic_debug/control
168
169 // enable all 12 messages in the function svc_process()
170 nullarbor:~ # echo -n 'func svc_process +p' >
171 <debugfs>/dynamic_debug/control
172
173 // disable all 12 messages in the function svc_process()
174 nullarbor:~ # echo -n 'func svc_process -p' >
175 <debugfs>/dynamic_debug/control
176
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177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
178 information.
604ff0dc 179
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180config DYNAMIC_DEBUG_CORE
181 bool "Enable core function of dynamic debug support"
182 depends on PRINTK
183 depends on (DEBUG_FS || PROC_FS)
184 help
185 Enable core functional support of dynamic debug. It is useful
186 when you want to tie dynamic debug to your kernel modules with
187 DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188 the case of embedded system where the kernel image size is
189 sensitive for people.
190
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191config SYMBOLIC_ERRNAME
192 bool "Support symbolic error names in printf"
193 default y if PRINTK
194 help
195 If you say Y here, the kernel's printf implementation will
196 be able to print symbolic error names such as ENOSPC instead
197 of the number 28. It makes the kernel image slightly larger
198 (about 3KB), but can make the kernel logs easier to read.
199
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200config DEBUG_BUGVERBOSE
201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
203 default y
204 help
205 Say Y here to make BUG() panics output the file name and line number
206 of the BUG call as well as the EIP and oops trace. This aids
207 debugging but costs about 70-100K of memory.
208
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209endmenu # "printk and dmesg options"
210
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211config DEBUG_KERNEL
212 bool "Kernel debugging"
213 help
214 Say Y here if you are developing drivers or trying to debug and
215 identify kernel problems.
216
217config DEBUG_MISC
218 bool "Miscellaneous debug code"
219 default DEBUG_KERNEL
220 depends on DEBUG_KERNEL
221 help
222 Say Y here if you need to enable miscellaneous debug code that should
223 be under a more specific debug option but isn't.
224
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225menu "Compile-time checks and compiler options"
226
227config DEBUG_INFO
f9b3cd24 228 bool
6dfc0665 229 help
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230 A kernel debug info option other than "None" has been selected
231 in the "Debug information" choice below, indicating that debug
232 information will be generated for build targets.
233
234choice
235 prompt "Debug information"
236 depends on DEBUG_KERNEL
237 help
238 Selecting something other than "None" results in a kernel image
239 that will include debugging info resulting in a larger kernel image.
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240 This adds debug symbols to the kernel and modules (gcc -g), and
241 is needed if you intend to use kernel crashdump or binary object
242 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
6dfc0665 243
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244 Choose which version of DWARF debug info to emit. If unsure,
245 select "Toolchain default".
246
247config DEBUG_INFO_NONE
248 bool "Disable debug information"
249 help
250 Do not build the kernel with debugging information, which will
251 result in a faster and smaller build.
252
253config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
254 bool "Rely on the toolchain's implicit default DWARF version"
255 select DEBUG_INFO
256 help
257 The implicit default version of DWARF debug info produced by a
258 toolchain changes over time.
259
260 This can break consumers of the debug info that haven't upgraded to
261 support newer revisions, and prevent testing newer versions, but
262 those should be less common scenarios.
263
264config DEBUG_INFO_DWARF4
265 bool "Generate DWARF Version 4 debuginfo"
266 select DEBUG_INFO
32ef9e50 267 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
f9b3cd24 268 help
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269 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
270 if using clang without clang's integrated assembler, and gdb 7.0+.
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271
272 If you have consumers of DWARF debug info that are not ready for
273 newer revisions of DWARF, you may wish to choose this or have your
274 config select this.
275
276config DEBUG_INFO_DWARF5
277 bool "Generate DWARF Version 5 debuginfo"
278 select DEBUG_INFO
279 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
280 help
281 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
282 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
283 draft features until 7.0), and gdb 8.0+.
284
285 Changes to the structure of debug info in Version 5 allow for around
286 15-18% savings in resulting image and debug info section sizes as
287 compared to DWARF Version 4. DWARF Version 5 standardizes previous
288 extensions such as accelerators for symbol indexing and the format
289 for fission (.dwo/.dwp) files. Users may not want to select this
290 config if they rely on tooling that has not yet been updated to
291 support DWARF Version 5.
292
293endchoice # "Debug information"
6dfc0665 294
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295if DEBUG_INFO
296
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297config DEBUG_INFO_REDUCED
298 bool "Reduce debugging information"
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299 help
300 If you say Y here gcc is instructed to generate less debugging
301 information for structure types. This means that tools that
302 need full debugging information (like kgdb or systemtap) won't
303 be happy. But if you merely need debugging information to
304 resolve line numbers there is no loss. Advantage is that
305 build directory object sizes shrink dramatically over a full
306 DEBUG_INFO build and compile times are reduced too.
307 Only works with newer gcc versions.
308
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309config DEBUG_INFO_COMPRESSED
310 bool "Compressed debugging information"
10e68b02 311 depends on $(cc-option,-gz=zlib)
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312 depends on $(ld-option,--compress-debug-sections=zlib)
313 help
314 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
315 5.0+, binutils 2.26+, and zlib.
316
317 Users of dpkg-deb via scripts/package/builddeb may find an increase in
318 size of their debug .deb packages with this config set, due to the
319 debug info being compressed with zlib, then the object files being
320 recompressed with a different compression scheme. But this is still
321 preferable to setting $KDEB_COMPRESS to "none" which would be even
322 larger.
323
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324config DEBUG_INFO_SPLIT
325 bool "Produce split debuginfo in .dwo files"
9d937444 326 depends on $(cc-option,-gsplit-dwarf)
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327 help
328 Generate debug info into separate .dwo files. This significantly
329 reduces the build directory size for builds with DEBUG_INFO,
330 because it stores the information only once on disk in .dwo
331 files instead of multiple times in object files and executables.
332 In addition the debug information is also compressed.
333
334 Requires recent gcc (4.7+) and recent gdb/binutils.
335 Any tool that packages or reads debug information would need
336 to know about the .dwo files and include them.
337 Incompatible with older versions of ccache.
338
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339config DEBUG_INFO_BTF
340 bool "Generate BTF typeinfo"
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341 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
342 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
d9847eb8 343 depends on BPF_SYSCALL
52deda95 344 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
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345 help
346 Generate deduplicated BTF type information from DWARF debug info.
347 Turning this on expects presence of pahole tool, which will convert
348 DWARF type info into equivalent deduplicated BTF type info.
349
5f9ae91f 350config PAHOLE_HAS_SPLIT_BTF
6323c813 351 def_bool PAHOLE_VERSION >= 119
5f9ae91f 352
7472d5a6 353config PAHOLE_HAS_BTF_TAG
6323c813 354 def_bool PAHOLE_VERSION >= 123
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355 depends on CC_IS_CLANG
356 help
357 Decide whether pahole emits btf_tag attributes (btf_type_tag and
358 btf_decl_tag) or not. Currently only clang compiler implements
359 these attributes, so make the config depend on CC_IS_CLANG.
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360
361config DEBUG_INFO_BTF_MODULES
362 def_bool y
363 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
364 help
365 Generate compact split BTF type information for kernel modules.
366
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367config MODULE_ALLOW_BTF_MISMATCH
368 bool "Allow loading modules with non-matching BTF type info"
369 depends on DEBUG_INFO_BTF_MODULES
370 help
371 For modules whose split BTF does not match vmlinux, load without
372 BTF rather than refusing to load. The default behavior with
373 module BTF enabled is to reject modules with such mismatches;
374 this option will still load module BTF where possible but ignore
375 it when a mismatch is found.
376
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377config GDB_SCRIPTS
378 bool "Provide GDB scripts for kernel debugging"
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379 help
380 This creates the required links to GDB helper scripts in the
381 build directory. If you load vmlinux into gdb, the helper
382 scripts will be automatically imported by gdb as well, and
383 additional functions are available to analyze a Linux kernel
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384 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
385 for further details.
3ee7b3fa 386
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387endif # DEBUG_INFO
388
35bb5b1e 389config FRAME_WARN
a83e4ca2 390 int "Warn for stack frames larger than"
35bb5b1e 391 range 0 8192
0e07f663 392 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
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393 default 2048 if PARISC
394 default 1536 if (!64BIT && XTENSA)
395 default 1024 if !64BIT
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396 default 2048 if 64BIT
397 help
398 Tell gcc to warn at build time for stack frames larger than this.
399 Setting this too low will cause a lot of warnings.
400 Setting it to 0 disables the warning.
35bb5b1e 401
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402config STRIP_ASM_SYMS
403 bool "Strip assembler-generated symbols during link"
404 default n
405 help
406 Strip internal assembler-generated symbols during a link (symbols
407 that look like '.Lxxx') so they don't pollute the output of
408 get_wchan() and suchlike.
409
1873e870 410config READABLE_ASM
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411 bool "Generate readable assembler code"
412 depends on DEBUG_KERNEL
7d73c3e9 413 depends on CC_IS_GCC
bf4735a4 414 help
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415 Disable some compiler optimizations that tend to generate human unreadable
416 assembler output. This may make the kernel slightly slower, but it helps
417 to keep kernel developers who have to stare a lot at assembler listings
418 sane.
bf4735a4 419
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420config HEADERS_INSTALL
421 bool "Install uapi headers to usr/include"
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422 depends on !UML
423 help
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424 This option will install uapi headers (headers exported to user-space)
425 into the usr/include directory for use during the kernel build.
426 This is unneeded for building the kernel itself, but needed for some
427 user-space program samples. It is also needed by some features such
428 as uapi header sanity checks.
429
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430config DEBUG_SECTION_MISMATCH
431 bool "Enable full Section mismatch analysis"
7d73c3e9 432 depends on CC_IS_GCC
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433 help
434 The section mismatch analysis checks if there are illegal
435 references from one section to another section.
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436 During linktime or runtime, some sections are dropped;
437 any use of code/data previously in these sections would
91341d4b 438 most likely result in an oops.
e809ab01 439 In the code, functions and variables are annotated with
0db0628d 440 __init,, etc. (see the full list in include/linux/init.h),
d6fbfa4f 441 which results in the code/data being placed in specific sections.
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442 The section mismatch analysis is always performed after a full
443 kernel build, and enabling this option causes the following
b7dca6dd 444 additional step to occur:
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445 - Add the option -fno-inline-functions-called-once to gcc commands.
446 When inlining a function annotated with __init in a non-init
447 function, we would lose the section information and thus
91341d4b 448 the analysis would not catch the illegal reference.
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449 This option tells gcc to inline less (but it does result in
450 a larger kernel).
91341d4b 451
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452config SECTION_MISMATCH_WARN_ONLY
453 bool "Make section mismatch errors non-fatal"
454 default y
455 help
456 If you say N here, the build process will fail if there are any
457 section mismatch, instead of just throwing warnings.
458
459 If unsure, say Y.
460
cf536e18 461config DEBUG_FORCE_FUNCTION_ALIGN_64B
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462 bool "Force all function address 64B aligned"
463 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
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464 help
465 There are cases that a commit from one domain changes the function
466 address alignment of other domains, and cause magic performance
467 bump (regression or improvement). Enable this option will help to
468 verify if the bump is caused by function alignment changes, while
469 it will slightly increase the kernel size and affect icache usage.
470
471 It is mainly for debug and performance tuning use.
472
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473#
474# Select this config option from the architecture Kconfig, if it
475# is preferred to always offer frame pointers as a config
476# option on the architecture (regardless of KERNEL_DEBUG):
477#
478config ARCH_WANT_FRAME_POINTERS
479 bool
f346f4b3 480
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481config FRAME_POINTER
482 bool "Compile the kernel with frame pointers"
a687a533 483 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
6dfc0665 484 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
a304e1b8 485 help
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486 If you say Y here the resulting kernel image will be slightly
487 larger and slower, but it gives very useful debugging information
488 in case of kernel bugs. (precise oopses/stacktraces/warnings)
a304e1b8 489
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490config OBJTOOL
491 bool
492
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493config STACK_VALIDATION
494 bool "Compile-time stack metadata validation"
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495 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
496 select OBJTOOL
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497 default n
498 help
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499 Validate frame pointer rules at compile-time. This helps ensure that
500 runtime stack traces are more reliable.
ee9f8fce 501
b9ab5ebb 502 For more information, see
d6a21f2d 503 tools/objtool/Documentation/objtool.txt.
b9ab5ebb 504
0f620cef 505config NOINSTR_VALIDATION
6804c1af 506 bool
489e355b 507 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
03f16cd0 508 select OBJTOOL
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509 default y
510
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511config VMLINUX_MAP
512 bool "Generate vmlinux.map file when linking"
513 depends on EXPERT
514 help
515 Selecting this option will pass "-Map=vmlinux.map" to ld
516 when linking vmlinux. That file can be useful for verifying
517 and debugging magic section games, and for seeing which
518 pieces of code get eliminated with
519 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
520
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521config DEBUG_FORCE_WEAK_PER_CPU
522 bool "Force weak per-cpu definitions"
523 depends on DEBUG_KERNEL
8446f1d3 524 help
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525 s390 and alpha require percpu variables in modules to be
526 defined weak to work around addressing range issue which
527 puts the following two restrictions on percpu variable
528 definitions.
8446f1d3 529
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530 1. percpu symbols must be unique whether static or not
531 2. percpu variables can't be defined inside a function
8446f1d3 532
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533 To ensure that generic code follows the above rules, this
534 option forces all percpu variables to be defined as weak.
5f329089 535
6dfc0665 536endmenu # "Compiler options"
8446f1d3 537
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538menu "Generic Kernel Debugging Instruments"
539
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540config MAGIC_SYSRQ
541 bool "Magic SysRq key"
542 depends on !UML
543 help
544 If you say Y here, you will have some control over the system even
545 if the system crashes for example during kernel debugging (e.g., you
546 will be able to flush the buffer cache to disk, reboot the system
547 immediately or dump some status information). This is accomplished
548 by pressing various keys while holding SysRq (Alt+PrintScreen). It
549 also works on a serial console (on PC hardware at least), if you
550 send a BREAK and then within 5 seconds a command keypress. The
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551 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
552 Don't say Y unless you really know what this hack does.
8446f1d3 553
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554config MAGIC_SYSRQ_DEFAULT_ENABLE
555 hex "Enable magic SysRq key functions by default"
556 depends on MAGIC_SYSRQ
557 default 0x1
558 help
559 Specifies which SysRq key functions are enabled by default.
560 This may be set to 1 or 0 to enable or disable them all, or
f8998c22 561 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
8eaede49 562
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563config MAGIC_SYSRQ_SERIAL
564 bool "Enable magic SysRq key over serial"
565 depends on MAGIC_SYSRQ
566 default y
567 help
568 Many embedded boards have a disconnected TTL level serial which can
569 generate some garbage that can lead to spurious false sysrq detects.
570 This option allows you to decide whether you want to enable the
571 magic SysRq key.
572
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573config MAGIC_SYSRQ_SERIAL_SEQUENCE
574 string "Char sequence that enables magic SysRq over serial"
575 depends on MAGIC_SYSRQ_SERIAL
576 default ""
577 help
578 Specifies a sequence of characters that can follow BREAK to enable
579 SysRq on a serial console.
580
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581 If unsure, leave an empty string and the option will not be enabled.
582
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583config DEBUG_FS
584 bool "Debug Filesystem"
585 help
586 debugfs is a virtual file system that kernel developers use to put
587 debugging files into. Enable this option to be able to read and
588 write to these files.
589
590 For detailed documentation on the debugfs API, see
591 Documentation/filesystems/.
592
593 If unsure, say N.
594
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595choice
596 prompt "Debugfs default access"
597 depends on DEBUG_FS
598 default DEBUG_FS_ALLOW_ALL
599 help
600 This selects the default access restrictions for debugfs.
601 It can be overridden with kernel command line option
602 debugfs=[on,no-mount,off]. The restrictions apply for API access
603 and filesystem registration.
604
605config DEBUG_FS_ALLOW_ALL
606 bool "Access normal"
607 help
608 No restrictions apply. Both API and filesystem registration
609 is on. This is the normal default operation.
610
611config DEBUG_FS_DISALLOW_MOUNT
612 bool "Do not register debugfs as filesystem"
613 help
614 The API is open but filesystem is not loaded. Clients can still do
615 their work and read with debug tools that do not need
616 debugfs filesystem.
617
618config DEBUG_FS_ALLOW_NONE
619 bool "No access"
620 help
621 Access is off. Clients get -PERM when trying to create nodes in
622 debugfs tree and debugfs is not registered as a filesystem.
623 Client can then back-off or continue without debugfs access.
624
625endchoice
626
6210b640 627source "lib/Kconfig.kgdb"
6210b640 628source "lib/Kconfig.ubsan"
2645d432 629source "lib/Kconfig.kcsan"
6210b640
CD
630
631endmenu
632
4d92b95f
ED
633menu "Networking Debugging"
634
635source "net/Kconfig.debug"
636
637endmenu # "Networking Debugging"
c66d7a27 638
0610c8a8 639menu "Memory Debugging"
fef2c9bc 640
8636a1f9 641source "mm/Kconfig.debug"
fef2c9bc 642
0610c8a8
DH
643config DEBUG_OBJECTS
644 bool "Debug object operations"
645 depends on DEBUG_KERNEL
9c44bc03 646 help
0610c8a8
DH
647 If you say Y here, additional code will be inserted into the
648 kernel to track the life time of various objects and validate
649 the operations on those objects.
9c44bc03 650
0610c8a8
DH
651config DEBUG_OBJECTS_SELFTEST
652 bool "Debug objects selftest"
653 depends on DEBUG_OBJECTS
654 help
655 This enables the selftest of the object debug code.
9c44bc03 656
0610c8a8
DH
657config DEBUG_OBJECTS_FREE
658 bool "Debug objects in freed memory"
659 depends on DEBUG_OBJECTS
660 help
661 This enables checks whether a k/v free operation frees an area
662 which contains an object which has not been deactivated
663 properly. This can make kmalloc/kfree-intensive workloads
664 much slower.
3ac7fe5a 665
c6f3a97f
TG
666config DEBUG_OBJECTS_TIMERS
667 bool "Debug timer objects"
668 depends on DEBUG_OBJECTS
669 help
670 If you say Y here, additional code will be inserted into the
671 timer routines to track the life time of timer objects and
672 validate the timer operations.
673
dc186ad7
TG
674config DEBUG_OBJECTS_WORK
675 bool "Debug work objects"
676 depends on DEBUG_OBJECTS
677 help
678 If you say Y here, additional code will be inserted into the
679 work queue routines to track the life time of work objects and
680 validate the work operations.
681
551d55a9
MD
682config DEBUG_OBJECTS_RCU_HEAD
683 bool "Debug RCU callbacks objects"
fc2ecf7e 684 depends on DEBUG_OBJECTS
551d55a9
MD
685 help
686 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
687
e2852ae8
TH
688config DEBUG_OBJECTS_PERCPU_COUNTER
689 bool "Debug percpu counter objects"
690 depends on DEBUG_OBJECTS
691 help
692 If you say Y here, additional code will be inserted into the
693 percpu counter routines to track the life time of percpu counter
694 objects and validate the percpu counter operations.
695
3ae70205
IM
696config DEBUG_OBJECTS_ENABLE_DEFAULT
697 int "debug_objects bootup default value (0-1)"
68d4b3df
KK
698 range 0 1
699 default "1"
700 depends on DEBUG_OBJECTS
701 help
702 Debug objects boot parameter default value
3ae70205 703
5035ebc6 704config SHRINKER_DEBUG
5035ebc6
RG
705 bool "Enable shrinker debugging support"
706 depends on DEBUG_FS
707 help
708 Say Y to enable the shrinker debugfs interface which provides
709 visibility into the kernel memory shrinkers subsystem.
710 Disable it to avoid an extra memory footprint.
711
b69ec42b
CM
712config HAVE_DEBUG_KMEMLEAK
713 bool
714
3bba00d7
CM
715config DEBUG_KMEMLEAK
716 bool "Kernel memory leak detector"
525c1f92 717 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
79e0d9bd 718 select DEBUG_FS
3bba00d7
CM
719 select STACKTRACE if STACKTRACE_SUPPORT
720 select KALLSYMS
b60e26a2 721 select CRC32
3bba00d7
CM
722 help
723 Say Y here if you want to enable the memory leak
724 detector. The memory allocation/freeing is traced in a way
725 similar to the Boehm's conservative garbage collector, the
726 difference being that the orphan objects are not freed but
727 only shown in /sys/kernel/debug/kmemleak. Enabling this
728 feature will introduce an overhead to memory
700199b0 729 allocations. See Documentation/dev-tools/kmemleak.rst for more
3bba00d7
CM
730 details.
731
0610c8a8
DH
732 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
733 of finding leaks due to the slab objects poisoning.
734
735 In order to access the kmemleak file, debugfs needs to be
736 mounted (usually at /sys/kernel/debug).
737
c5665868
CM
738config DEBUG_KMEMLEAK_MEM_POOL_SIZE
739 int "Kmemleak memory pool size"
0610c8a8 740 depends on DEBUG_KMEMLEAK
c59180ae 741 range 200 1000000
b751c52b 742 default 16000
0610c8a8
DH
743 help
744 Kmemleak must track all the memory allocations to avoid
745 reporting false positives. Since memory may be allocated or
c5665868
CM
746 freed before kmemleak is fully initialised, use a static pool
747 of metadata objects to track such callbacks. After kmemleak is
748 fully initialised, this memory pool acts as an emergency one
749 if slab allocations fail.
0610c8a8
DH
750
751config DEBUG_KMEMLEAK_TEST
752 tristate "Simple test for the kernel memory leak detector"
753 depends on DEBUG_KMEMLEAK && m
754 help
755 This option enables a module that explicitly leaks memory.
756
757 If unsure, say N.
758
759config DEBUG_KMEMLEAK_DEFAULT_OFF
760 bool "Default kmemleak to off"
761 depends on DEBUG_KMEMLEAK
762 help
763 Say Y here to disable kmemleak by default. It can then be enabled
764 on the command line via kmemleak=on.
765
d53ce042
SK
766config DEBUG_KMEMLEAK_AUTO_SCAN
767 bool "Enable kmemleak auto scan thread on boot up"
768 default y
769 depends on DEBUG_KMEMLEAK
770 help
771 Depending on the cpu, kmemleak scan may be cpu intensive and can
772 stall user tasks at times. This option enables/disables automatic
773 kmemleak scan at boot up.
774
775 Say N here to disable kmemleak auto scan thread to stop automatic
776 scanning. Disabling this option disables automatic reporting of
777 memory leaks.
778
779 If unsure, say Y.
780
0610c8a8
DH
781config DEBUG_STACK_USAGE
782 bool "Stack utilization instrumentation"
6c31da34 783 depends on DEBUG_KERNEL && !IA64
0610c8a8
DH
784 help
785 Enables the display of the minimum amount of free stack which each
786 task has ever had available in the sysrq-T and sysrq-P debug output.
787
788 This option will slow down process creation somewhat.
789
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CD
790config SCHED_STACK_END_CHECK
791 bool "Detect stack corruption on calls to schedule()"
792 depends on DEBUG_KERNEL
793 default n
794 help
795 This option checks for a stack overrun on calls to schedule().
796 If the stack end location is found to be over written always panic as
797 the content of the corrupted region can no longer be trusted.
798 This is to ensure no erroneous behaviour occurs which could result in
799 data corruption or a sporadic crash at a later stage once the region
800 is examined. The runtime overhead introduced is minimal.
801
399145f9
AK
802config ARCH_HAS_DEBUG_VM_PGTABLE
803 bool
804 help
805 An architecture should select this when it can successfully
806 build and run DEBUG_VM_PGTABLE.
807
a738e9ba
TG
808config DEBUG_VM_IRQSOFF
809 def_bool DEBUG_VM && !PREEMPT_RT
810
0610c8a8
DH
811config DEBUG_VM
812 bool "Debug VM"
813 depends on DEBUG_KERNEL
814 help
815 Enable this to turn on extended checks in the virtual-memory system
68d4b3df 816 that may impact performance.
0610c8a8
DH
817
818 If unsure, say N.
819
54a611b6
LH
820config DEBUG_VM_MAPLE_TREE
821 bool "Debug VM maple trees"
4f115147 822 depends on DEBUG_VM
54a611b6 823 select DEBUG_MAPLE_TREE
4f115147 824 help
54a611b6 825 Enable VM maple tree debugging information and extra validations.
4f115147
DB
826
827 If unsure, say N.
828
0610c8a8
DH
829config DEBUG_VM_RB
830 bool "Debug VM red-black trees"
831 depends on DEBUG_VM
832 help
a663dad6 833 Enable VM red-black tree debugging information and extra validations.
0610c8a8
DH
834
835 If unsure, say N.
836
95ad9755
KS
837config DEBUG_VM_PGFLAGS
838 bool "Debug page-flags operations"
839 depends on DEBUG_VM
840 help
841 Enables extra validation on page flags operations.
842
843 If unsure, say N.
844
399145f9
AK
845config DEBUG_VM_PGTABLE
846 bool "Debug arch page table for semantics compliance"
847 depends on MMU
848 depends on ARCH_HAS_DEBUG_VM_PGTABLE
849 default y if DEBUG_VM
850 help
851 This option provides a debug method which can be used to test
852 architecture page table helper functions on various platforms in
853 verifying if they comply with expected generic MM semantics. This
854 will help architecture code in making sure that any changes or
855 new additions of these helpers still conform to expected
856 semantics of the generic MM. Platforms will have to opt in for
857 this through ARCH_HAS_DEBUG_VM_PGTABLE.
858
859 If unsure, say N.
860
fa5b6ec9
LA
861config ARCH_HAS_DEBUG_VIRTUAL
862 bool
863
0610c8a8
DH
864config DEBUG_VIRTUAL
865 bool "Debug VM translations"
fa5b6ec9 866 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
0610c8a8
DH
867 help
868 Enable some costly sanity checks in virtual to page code. This can
869 catch mistakes with virt_to_page() and friends.
870
871 If unsure, say N.
872
873config DEBUG_NOMMU_REGIONS
874 bool "Debug the global anon/private NOMMU mapping region tree"
875 depends on DEBUG_KERNEL && !MMU
876 help
877 This option causes the global tree of anonymous and private mapping
878 regions to be regularly checked for invalid topology.
879
880config DEBUG_MEMORY_INIT
881 bool "Debug memory initialisation" if EXPERT
882 default !EXPERT
883 help
884 Enable this for additional checks during memory initialisation.
885 The sanity checks verify aspects of the VM such as the memory model
886 and other information provided by the architecture. Verbose
887 information will be printed at KERN_DEBUG loglevel depending
888 on the mminit_loglevel= command-line option.
889
890 If unsure, say Y
891
892config MEMORY_NOTIFIER_ERROR_INJECT
893 tristate "Memory hotplug notifier error injection module"
50f9481e 894 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
0610c8a8
DH
895 help
896 This option provides the ability to inject artificial errors to
897 memory hotplug notifier chain callbacks. It is controlled through
898 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
899
900 If the notifier call chain should be failed with some events
901 notified, write the error code to "actions/<notifier event>/error".
902
903 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
904
905 # cd /sys/kernel/debug/notifier-error-inject/memory
906 # echo -12 > actions/MEM_GOING_OFFLINE/error
907 # echo offline > /sys/devices/system/memory/memoryXXX/state
908 bash: echo: write error: Cannot allocate memory
909
910 To compile this code as a module, choose M here: the module will
911 be called memory-notifier-error-inject.
912
913 If unsure, say N.
914
915config DEBUG_PER_CPU_MAPS
916 bool "Debug access to per_cpu maps"
917 depends on DEBUG_KERNEL
918 depends on SMP
919 help
920 Say Y to verify that the per_cpu map being accessed has
921 been set up. This adds a fair amount of code to kernel memory
922 and decreases performance.
923
924 Say N if unsure.
925
6e799cb6
TG
926config DEBUG_KMAP_LOCAL
927 bool "Debug kmap_local temporary mappings"
928 depends on DEBUG_KERNEL && KMAP_LOCAL
929 help
930 This option enables additional error checking for the kmap_local
931 infrastructure. Disable for production use.
932
0e91a0c6
TG
933config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
934 bool
935
936config DEBUG_KMAP_LOCAL_FORCE_MAP
937 bool "Enforce kmap_local temporary mappings"
938 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
939 select KMAP_LOCAL
940 select DEBUG_KMAP_LOCAL
941 help
942 This option enforces temporary mappings through the kmap_local
943 mechanism for non-highmem pages and on non-highmem systems.
944 Disable this for production systems!
945
0610c8a8
DH
946config DEBUG_HIGHMEM
947 bool "Highmem debugging"
948 depends on DEBUG_KERNEL && HIGHMEM
0e91a0c6 949 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
6e799cb6 950 select DEBUG_KMAP_LOCAL
0610c8a8 951 help
b1357c9f
GU
952 This option enables additional error checking for high memory
953 systems. Disable for production systems.
0610c8a8
DH
954
955config HAVE_DEBUG_STACKOVERFLOW
956 bool
957
958config DEBUG_STACKOVERFLOW
959 bool "Check for stack overflows"
960 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
a7f7f624 961 help
0610c8a8 962 Say Y here if you want to check for overflows of kernel, IRQ
edb0ec07 963 and exception stacks (if your architecture uses them). This
0610c8a8
DH
964 option will show detailed messages if free stack space drops
965 below a certain limit.
966
967 These kinds of bugs usually occur when call-chains in the
968 kernel get too deep, especially when interrupts are
969 involved.
970
971 Use this in cases where you see apparently random memory
972 corruption, especially if it appears in 'struct thread_info'
973
974 If in doubt, say "N".
975
0b24becc 976source "lib/Kconfig.kasan"
0ce20dd8 977source "lib/Kconfig.kfence"
f80be457 978source "lib/Kconfig.kmsan"
0b24becc 979
0610c8a8
DH
980endmenu # "Memory Debugging"
981
a304e1b8
DW
982config DEBUG_SHIRQ
983 bool "Debug shared IRQ handlers"
0244ad00 984 depends on DEBUG_KERNEL
a304e1b8 985 help
0a2fae2a
WS
986 Enable this to generate a spurious interrupt just before a shared
987 interrupt handler is deregistered (generating one when registering
988 is currently disabled). Drivers need to handle this correctly. Some
989 don't and need to be caught.
a304e1b8 990
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CD
991menu "Debug Oops, Lockups and Hangs"
992
993config PANIC_ON_OOPS
994 bool "Panic on Oops"
995 help
996 Say Y here to enable the kernel to panic when it oopses. This
997 has the same effect as setting oops=panic on the kernel command
998 line.
999
1000 This feature is useful to ensure that the kernel does not do
1001 anything erroneous after an oops which could result in data
1002 corruption or other issues.
1003
1004 Say N if unsure.
1005
1006config PANIC_ON_OOPS_VALUE
1007 int
1008 range 0 1
1009 default 0 if !PANIC_ON_OOPS
1010 default 1 if PANIC_ON_OOPS
1011
1012config PANIC_TIMEOUT
1013 int "panic timeout"
1014 default 0
1015 help
9d5b134f 1016 Set the timeout value (in seconds) until a reboot occurs when
f43a289d
CD
1017 the kernel panics. If n = 0, then we wait forever. A timeout
1018 value n > 0 will wait n seconds before rebooting, while a timeout
1019 value n < 0 will reboot immediately.
92aef8fb 1020
58687acb 1021config LOCKUP_DETECTOR
05a4a952
NP
1022 bool
1023
1024config SOFTLOCKUP_DETECTOR
1025 bool "Detect Soft Lockups"
dea20a3f 1026 depends on DEBUG_KERNEL && !S390
05a4a952 1027 select LOCKUP_DETECTOR
8446f1d3 1028 help
58687acb 1029 Say Y here to enable the kernel to act as a watchdog to detect
05a4a952 1030 soft lockups.
58687acb
DZ
1031
1032 Softlockups are bugs that cause the kernel to loop in kernel
5f329089 1033 mode for more than 20 seconds, without giving other tasks a
58687acb
DZ
1034 chance to run. The current stack trace is displayed upon
1035 detection and the system will stay locked up.
8446f1d3 1036
5f00ae0d
RD
1037config BOOTPARAM_SOFTLOCKUP_PANIC
1038 bool "Panic (Reboot) On Soft Lockups"
1039 depends on SOFTLOCKUP_DETECTOR
1040 help
1041 Say Y here to enable the kernel to panic on "soft lockups",
1042 which are bugs that cause the kernel to loop in kernel
1043 mode for more than 20 seconds (configurable using the watchdog_thresh
1044 sysctl), without giving other tasks a chance to run.
1045
1046 The panic can be used in combination with panic_timeout,
1047 to cause the system to reboot automatically after a
1048 lockup has been detected. This feature is useful for
1049 high-availability systems that have uptime guarantees and
1050 where a lockup must be resolved ASAP.
1051
1052 Say N if unsure.
1053
05a4a952
NP
1054config HARDLOCKUP_DETECTOR_PERF
1055 bool
1056 select SOFTLOCKUP_DETECTOR
1057
7edaeb68
TG
1058#
1059# Enables a timestamp based low pass filter to compensate for perf based
1060# hard lockup detection which runs too fast due to turbo modes.
1061#
1062config HARDLOCKUP_CHECK_TIMESTAMP
1063 bool
1064
05a4a952
NP
1065#
1066# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1067# lockup detector rather than the perf based detector.
1068#
1069config HARDLOCKUP_DETECTOR
1070 bool "Detect Hard Lockups"
1071 depends on DEBUG_KERNEL && !S390
1072 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1073 select LOCKUP_DETECTOR
1074 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
05a4a952
NP
1075 help
1076 Say Y here to enable the kernel to act as a watchdog to detect
1077 hard lockups.
1078
58687acb 1079 Hardlockups are bugs that cause the CPU to loop in kernel mode
5f329089 1080 for more than 10 seconds, without letting other interrupts have a
58687acb
DZ
1081 chance to run. The current stack trace is displayed upon detection
1082 and the system will stay locked up.
8446f1d3 1083
fef2c9bc
DZ
1084config BOOTPARAM_HARDLOCKUP_PANIC
1085 bool "Panic (Reboot) On Hard Lockups"
8f1f66ed 1086 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
1087 help
1088 Say Y here to enable the kernel to panic on "hard lockups",
1089 which are bugs that cause the kernel to loop in kernel
5f329089
FLVC
1090 mode with interrupts disabled for more than 10 seconds (configurable
1091 using the watchdog_thresh sysctl).
fef2c9bc
DZ
1092
1093 Say N if unsure.
1094
e162b39a
MSB
1095config DETECT_HUNG_TASK
1096 bool "Detect Hung Tasks"
1097 depends on DEBUG_KERNEL
05a4a952 1098 default SOFTLOCKUP_DETECTOR
e162b39a 1099 help
0610c8a8
DH
1100 Say Y here to enable the kernel to detect "hung tasks",
1101 which are bugs that cause the task to be stuck in
96b03ab8 1102 uninterruptible "D" state indefinitely.
1da177e4 1103
0610c8a8
DH
1104 When a hung task is detected, the kernel will print the
1105 current stack trace (which you should report), but the
1106 task will stay in uninterruptible state. If lockdep is
1107 enabled then all held locks will also be reported. This
1108 feature has negligible overhead.
871751e2 1109
0610c8a8
DH
1110config DEFAULT_HUNG_TASK_TIMEOUT
1111 int "Default timeout for hung task detection (in seconds)"
1112 depends on DETECT_HUNG_TASK
1113 default 120
f0630fff 1114 help
0610c8a8
DH
1115 This option controls the default timeout (in seconds) used
1116 to determine when a task has become non-responsive and should
1117 be considered hung.
f0630fff 1118
0610c8a8
DH
1119 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1120 sysctl or by writing a value to
1121 /proc/sys/kernel/hung_task_timeout_secs.
8ff12cfc 1122
0610c8a8
DH
1123 A timeout of 0 disables the check. The default is two minutes.
1124 Keeping the default should be fine in most cases.
b69ec42b 1125
0610c8a8
DH
1126config BOOTPARAM_HUNG_TASK_PANIC
1127 bool "Panic (Reboot) On Hung Tasks"
1128 depends on DETECT_HUNG_TASK
3bba00d7 1129 help
0610c8a8
DH
1130 Say Y here to enable the kernel to panic on "hung tasks",
1131 which are bugs that cause the kernel to leave a task stuck
1132 in uninterruptible "D" state.
3bba00d7 1133
0610c8a8
DH
1134 The panic can be used in combination with panic_timeout,
1135 to cause the system to reboot automatically after a
1136 hung task has been detected. This feature is useful for
1137 high-availability systems that have uptime guarantees and
1138 where a hung tasks must be resolved ASAP.
bf96d1e3 1139
0610c8a8 1140 Say N if unsure.
bf96d1e3 1141
82607adc
TH
1142config WQ_WATCHDOG
1143 bool "Detect Workqueue Stalls"
1144 depends on DEBUG_KERNEL
1145 help
1146 Say Y here to enable stall detection on workqueues. If a
1147 worker pool doesn't make forward progress on a pending work
1148 item for over a given amount of time, 30s by default, a
1149 warning message is printed along with dump of workqueue
1150 state. This can be configured through kernel parameter
1151 "workqueue.watchdog_thresh" and its sysfs counterpart.
1152
30428ef5
KK
1153config TEST_LOCKUP
1154 tristate "Test module to generate lockups"
63646bc9 1155 depends on m
30428ef5
KK
1156 help
1157 This builds the "test_lockup" module that helps to make sure
1158 that watchdogs and lockup detectors are working properly.
1159
1160 Depending on module parameters it could emulate soft or hard
1161 lockup, "hung task", or locking arbitrary lock for a long time.
1162 Also it could generate series of lockups with cooling-down periods.
1163
1164 If unsure, say N.
1165
92aef8fb
DH
1166endmenu # "Debug lockups and hangs"
1167
ebebdd09 1168menu "Scheduler Debugging"
5800dc3c 1169
0610c8a8
DH
1170config SCHED_DEBUG
1171 bool "Collect scheduler debugging info"
1172 depends on DEBUG_KERNEL && PROC_FS
1173 default y
0822ee4a 1174 help
0610c8a8
DH
1175 If you say Y here, the /proc/sched_debug file will be provided
1176 that can help debug the scheduler. The runtime overhead of this
1177 option is minimal.
0822ee4a 1178
f6db8347
NR
1179config SCHED_INFO
1180 bool
1181 default n
1182
0610c8a8
DH
1183config SCHEDSTATS
1184 bool "Collect scheduler statistics"
1185 depends on DEBUG_KERNEL && PROC_FS
f6db8347 1186 select SCHED_INFO
0610c8a8
DH
1187 help
1188 If you say Y here, additional code will be inserted into the
1189 scheduler and related routines to collect statistics about
1190 scheduler behavior and provide them in /proc/schedstat. These
1191 stats may be useful for both tuning and debugging the scheduler
1192 If you aren't debugging the scheduler or trying to tune a specific
1193 application, you can say N to avoid the very slight overhead
1194 this adds.
0822ee4a 1195
ebebdd09 1196endmenu
0d9e2632 1197
3c17ad19
JS
1198config DEBUG_TIMEKEEPING
1199 bool "Enable extra timekeeping sanity checking"
1200 help
1201 This option will enable additional timekeeping sanity checks
1202 which may be helpful when diagnosing issues where timekeeping
1203 problems are suspected.
1204
1205 This may include checks in the timekeeping hotpaths, so this
1206 option may have a (very small) performance impact to some
1207 workloads.
1208
1209 If unsure, say N.
1210
1da177e4
LT
1211config DEBUG_PREEMPT
1212 bool "Debug preemptible kernel"
9f472869 1213 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1da177e4
LT
1214 default y
1215 help
1216 If you say Y here then the kernel will use a debug variant of the
1217 commonly used smp_processor_id() function and will print warnings
1218 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1219 will detect preemption count underflows.
1220
9eade16b
DH
1221menu "Lock Debugging (spinlocks, mutexes, etc...)"
1222
f07cbebb
WL
1223config LOCK_DEBUGGING_SUPPORT
1224 bool
1225 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1226 default y
1227
19193bca
WL
1228config PROVE_LOCKING
1229 bool "Lock debugging: prove locking correctness"
1230 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1231 select LOCKDEP
1232 select DEBUG_SPINLOCK
bb630f9f 1233 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca 1234 select DEBUG_RT_MUTEXES if RT_MUTEXES
c71fd893 1235 select DEBUG_RWSEMS
19193bca
WL
1236 select DEBUG_WW_MUTEX_SLOWPATH
1237 select DEBUG_LOCK_ALLOC
8fd8ad5c 1238 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
19193bca
WL
1239 select TRACE_IRQFLAGS
1240 default n
1241 help
1242 This feature enables the kernel to prove that all locking
1243 that occurs in the kernel runtime is mathematically
1244 correct: that under no circumstance could an arbitrary (and
1245 not yet triggered) combination of observed locking
1246 sequences (on an arbitrary number of CPUs, running an
1247 arbitrary number of tasks and interrupt contexts) cause a
1248 deadlock.
1249
1250 In short, this feature enables the kernel to report locking
1251 related deadlocks before they actually occur.
1252
1253 The proof does not depend on how hard and complex a
1254 deadlock scenario would be to trigger: how many
1255 participant CPUs, tasks and irq-contexts would be needed
1256 for it to trigger. The proof also does not depend on
1257 timing: if a race and a resulting deadlock is possible
1258 theoretically (no matter how unlikely the race scenario
1259 is), it will be proven so and will immediately be
1260 reported by the kernel (once the event is observed that
1261 makes the deadlock theoretically possible).
1262
1263 If a deadlock is impossible (i.e. the locking rules, as
1264 observed by the kernel, are mathematically correct), the
1265 kernel reports nothing.
1266
1267 NOTE: this feature can also be enabled for rwlocks, mutexes
1268 and rwsems - in which case all dependencies between these
1269 different locking variants are observed and mapped too, and
1270 the proof of observed correctness is also maintained for an
1271 arbitrary combination of these separate locking variants.
1272
387b1468 1273 For more details, see Documentation/locking/lockdep-design.rst.
19193bca 1274
de8f5e4f
PZ
1275config PROVE_RAW_LOCK_NESTING
1276 bool "Enable raw_spinlock - spinlock nesting checks"
1277 depends on PROVE_LOCKING
1278 default n
1279 help
1280 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1281 that the lock nesting rules for PREEMPT_RT enabled kernels are
1282 not violated.
1283
1284 NOTE: There are known nesting problems. So if you enable this
1285 option expect lockdep splats until these problems have been fully
1286 addressed which is work in progress. This config switch allows to
1287 identify and analyze these problems. It will be removed and the
9dbbc3b9 1288 check permanently enabled once the main issues have been fixed.
de8f5e4f
PZ
1289
1290 If unsure, select N.
1291
19193bca
WL
1292config LOCK_STAT
1293 bool "Lock usage statistics"
1294 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1295 select LOCKDEP
1296 select DEBUG_SPINLOCK
bb630f9f 1297 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca
WL
1298 select DEBUG_RT_MUTEXES if RT_MUTEXES
1299 select DEBUG_LOCK_ALLOC
1300 default n
1301 help
1302 This feature enables tracking lock contention points
1303
387b1468 1304 For more details, see Documentation/locking/lockstat.rst
19193bca
WL
1305
1306 This also enables lock events required by "perf lock",
1307 subcommand of perf.
1308 If you want to use "perf lock", you also need to turn on
1309 CONFIG_EVENT_TRACING.
1310
1311 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1312 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1313
e7eebaf6
IM
1314config DEBUG_RT_MUTEXES
1315 bool "RT Mutex debugging, deadlock detection"
e7eebaf6
IM
1316 depends on DEBUG_KERNEL && RT_MUTEXES
1317 help
1318 This allows rt mutex semantics violations and rt mutex related
1319 deadlocks (lockups) to be detected and reported automatically.
1320
1da177e4 1321config DEBUG_SPINLOCK
4d9f34ad 1322 bool "Spinlock and rw-lock debugging: basic checks"
1da177e4 1323 depends on DEBUG_KERNEL
e335e3eb 1324 select UNINLINE_SPIN_UNLOCK
1da177e4
LT
1325 help
1326 Say Y here and build SMP to catch missing spinlock initialization
1327 and certain other kinds of spinlock errors commonly made. This is
1328 best used in conjunction with the NMI watchdog so that spinlock
1329 deadlocks are also debuggable.
1330
4d9f34ad
IM
1331config DEBUG_MUTEXES
1332 bool "Mutex debugging: basic checks"
bb630f9f 1333 depends on DEBUG_KERNEL && !PREEMPT_RT
4d9f34ad
IM
1334 help
1335 This feature allows mutex semantics violations to be detected and
1336 reported.
1337
23010027
DV
1338config DEBUG_WW_MUTEX_SLOWPATH
1339 bool "Wait/wound mutex debugging: Slowpath testing"
f07cbebb 1340 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
23010027
DV
1341 select DEBUG_LOCK_ALLOC
1342 select DEBUG_SPINLOCK
bb630f9f
TG
1343 select DEBUG_MUTEXES if !PREEMPT_RT
1344 select DEBUG_RT_MUTEXES if PREEMPT_RT
23010027
DV
1345 help
1346 This feature enables slowpath testing for w/w mutex users by
1347 injecting additional -EDEADLK wound/backoff cases. Together with
1348 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1349 will test all possible w/w mutex interface abuse with the
1350 exception of simply not acquiring all the required locks.
4d692373
RC
1351 Note that this feature can introduce significant overhead, so
1352 it really should not be enabled in a production or distro kernel,
1353 even a debug kernel. If you are a driver writer, enable it. If
1354 you are a distro, do not.
23010027 1355
5149cbac
WL
1356config DEBUG_RWSEMS
1357 bool "RW Semaphore debugging: basic checks"
c71fd893 1358 depends on DEBUG_KERNEL
5149cbac 1359 help
c71fd893
WL
1360 This debugging feature allows mismatched rw semaphore locks
1361 and unlocks to be detected and reported.
5149cbac 1362
4d9f34ad
IM
1363config DEBUG_LOCK_ALLOC
1364 bool "Lock debugging: detect incorrect freeing of live locks"
f07cbebb 1365 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1366 select DEBUG_SPINLOCK
bb630f9f 1367 select DEBUG_MUTEXES if !PREEMPT_RT
f5694788 1368 select DEBUG_RT_MUTEXES if RT_MUTEXES
4d9f34ad
IM
1369 select LOCKDEP
1370 help
1371 This feature will check whether any held lock (spinlock, rwlock,
1372 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1373 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1374 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1375 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1376 held during task exit.
1377
4d9f34ad
IM
1378config LOCKDEP
1379 bool
f07cbebb 1380 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1381 select STACKTRACE
4d9f34ad
IM
1382 select KALLSYMS
1383 select KALLSYMS_ALL
1384
395102db
DJ
1385config LOCKDEP_SMALL
1386 bool
1387
5dc33592
TH
1388config LOCKDEP_BITS
1389 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1390 depends on LOCKDEP && !LOCKDEP_SMALL
1391 range 10 30
1392 default 15
1393 help
1394 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1395
1396config LOCKDEP_CHAINS_BITS
1397 int "Bitsize for MAX_LOCKDEP_CHAINS"
1398 depends on LOCKDEP && !LOCKDEP_SMALL
1399 range 10 30
1400 default 16
1401 help
1402 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1403
1404config LOCKDEP_STACK_TRACE_BITS
1405 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1406 depends on LOCKDEP && !LOCKDEP_SMALL
1407 range 10 30
1408 default 19
1409 help
1410 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1411
1412config LOCKDEP_STACK_TRACE_HASH_BITS
1413 int "Bitsize for STACK_TRACE_HASH_SIZE"
1414 depends on LOCKDEP && !LOCKDEP_SMALL
1415 range 10 30
1416 default 14
1417 help
1418 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1419
1420config LOCKDEP_CIRCULAR_QUEUE_BITS
1421 int "Bitsize for elements in circular_queue struct"
1422 depends on LOCKDEP
1423 range 10 30
1424 default 12
1425 help
1426 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1427
4d9f34ad
IM
1428config DEBUG_LOCKDEP
1429 bool "Lock dependency engine debugging"
517e7aa5 1430 depends on DEBUG_KERNEL && LOCKDEP
997acaf6 1431 select DEBUG_IRQFLAGS
4d9f34ad
IM
1432 help
1433 If you say Y here, the lock dependency engine will do
1434 additional runtime checks to debug itself, at the price
1435 of more runtime overhead.
1436
d902db1e
FW
1437config DEBUG_ATOMIC_SLEEP
1438 bool "Sleep inside atomic section checking"
e8f7c70f 1439 select PREEMPT_COUNT
1da177e4 1440 depends on DEBUG_KERNEL
87a4c375 1441 depends on !ARCH_NO_PREEMPT
1da177e4
LT
1442 help
1443 If you say Y here, various routines which may sleep will become very
d902db1e
FW
1444 noisy if they are called inside atomic sections: when a spinlock is
1445 held, inside an rcu read side critical section, inside preempt disabled
1446 sections, inside an interrupt, etc...
1da177e4 1447
cae2ed9a
IM
1448config DEBUG_LOCKING_API_SELFTESTS
1449 bool "Locking API boot-time self-tests"
1450 depends on DEBUG_KERNEL
1451 help
1452 Say Y here if you want the kernel to run a short self-test during
1453 bootup. The self-test checks whether common types of locking bugs
1454 are detected by debugging mechanisms or not. (if you disable
9dbbc3b9 1455 lock debugging then those bugs won't be detected of course.)
cae2ed9a
IM
1456 The following locking APIs are covered: spinlocks, rwlocks,
1457 mutexes and rwsems.
1458
0af3fe1e
PM
1459config LOCK_TORTURE_TEST
1460 tristate "torture tests for locking"
1461 depends on DEBUG_KERNEL
1462 select TORTURE_TEST
0af3fe1e
PM
1463 help
1464 This option provides a kernel module that runs torture tests
1465 on kernel locking primitives. The kernel module may be built
1466 after the fact on the running kernel to be tested, if desired.
1467
1468 Say Y here if you want kernel locking-primitive torture tests
1469 to be built into the kernel.
1470 Say M if you want these torture tests to build as a module.
1471 Say N if you are unsure.
1472
f2a5fec1
CW
1473config WW_MUTEX_SELFTEST
1474 tristate "Wait/wound mutex selftests"
1475 help
1476 This option provides a kernel module that runs tests on the
1477 on the struct ww_mutex locking API.
1478
1479 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1480 with this test harness.
1481
1482 Say M if you want these self tests to build as a module.
1483 Say N if you are unsure.
1484
e9d338a0
PM
1485config SCF_TORTURE_TEST
1486 tristate "torture tests for smp_call_function*()"
1487 depends on DEBUG_KERNEL
1488 select TORTURE_TEST
1489 help
1490 This option provides a kernel module that runs torture tests
1491 on the smp_call_function() family of primitives. The kernel
1492 module may be built after the fact on the running kernel to
1493 be tested, if desired.
1494
35feb604
PM
1495config CSD_LOCK_WAIT_DEBUG
1496 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1497 depends on DEBUG_KERNEL
1498 depends on 64BIT
1499 default n
1500 help
1501 This option enables debug prints when CPUs are slow to respond
1502 to the smp_call_function*() IPI wrappers. These debug prints
1503 include the IPI handler function currently executing (if any)
1504 and relevant stack traces.
1505
9eade16b 1506endmenu # lock debugging
8637c099 1507
9eade16b 1508config TRACE_IRQFLAGS
ed004953 1509 depends on TRACE_IRQFLAGS_SUPPORT
9eade16b 1510 bool
5ca43f6c 1511 help
9eade16b
DH
1512 Enables hooks to interrupt enabling and disabling for
1513 either tracing or lock debugging.
5ca43f6c 1514
ed004953 1515config TRACE_IRQFLAGS_NMI
1516 def_bool y
1517 depends on TRACE_IRQFLAGS
1518 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1519
997acaf6
MR
1520config DEBUG_IRQFLAGS
1521 bool "Debug IRQ flag manipulation"
1522 help
1523 Enables checks for potentially unsafe enabling or disabling of
1524 interrupts, such as calling raw_local_irq_restore() when interrupts
1525 are enabled.
1526
8637c099 1527config STACKTRACE
0c38e1fe 1528 bool "Stack backtrace support"
8637c099 1529 depends on STACKTRACE_SUPPORT
0c38e1fe
DJ
1530 help
1531 This option causes the kernel to create a /proc/pid/stack for
1532 every process, showing its current stack trace.
1533 It is also used by various kernel debugging features that require
1534 stack trace generation.
5ca43f6c 1535
eecabf56
TT
1536config WARN_ALL_UNSEEDED_RANDOM
1537 bool "Warn for all uses of unseeded randomness"
1538 default n
d06bfd19
JD
1539 help
1540 Some parts of the kernel contain bugs relating to their use of
1541 cryptographically secure random numbers before it's actually possible
1542 to generate those numbers securely. This setting ensures that these
1543 flaws don't go unnoticed, by enabling a message, should this ever
1544 occur. This will allow people with obscure setups to know when things
1545 are going wrong, so that they might contact developers about fixing
1546 it.
1547
eecabf56
TT
1548 Unfortunately, on some models of some architectures getting
1549 a fully seeded CRNG is extremely difficult, and so this can
1550 result in dmesg getting spammed for a surprisingly long
1551 time. This is really bad from a security perspective, and
1552 so architecture maintainers really need to do what they can
1553 to get the CRNG seeded sooner after the system is booted.
4c5d114e 1554 However, since users cannot do anything actionable to
cc1e127b 1555 address this, by default this option is disabled.
eecabf56
TT
1556
1557 Say Y here if you want to receive warnings for all uses of
1558 unseeded randomness. This will be of use primarily for
4c5d114e 1559 those developers interested in improving the security of
eecabf56
TT
1560 Linux kernels running on their architecture (or
1561 subarchitecture).
d06bfd19 1562
1da177e4
LT
1563config DEBUG_KOBJECT
1564 bool "kobject debugging"
1565 depends on DEBUG_KERNEL
1566 help
1567 If you say Y here, some extra kobject debugging messages will be sent
aca52c39 1568 to the syslog.
1da177e4 1569
c817a67e
RK
1570config DEBUG_KOBJECT_RELEASE
1571 bool "kobject release debugging"
2a999aa0 1572 depends on DEBUG_OBJECTS_TIMERS
c817a67e
RK
1573 help
1574 kobjects are reference counted objects. This means that their
1575 last reference count put is not predictable, and the kobject can
b6c69474 1576 live on past the point at which a driver decides to drop its
c817a67e
RK
1577 initial reference to the kobject gained on allocation. An
1578 example of this would be a struct device which has just been
1579 unregistered.
1580
1581 However, some buggy drivers assume that after such an operation,
1582 the memory backing the kobject can be immediately freed. This
1583 goes completely against the principles of a refcounted object.
1584
1585 If you say Y here, the kernel will delay the release of kobjects
1586 on the last reference count to improve the visibility of this
1587 kind of kobject release bug.
1588
9b2a60c4
CM
1589config HAVE_DEBUG_BUGVERBOSE
1590 bool
1591
3be5cbcd 1592menu "Debug kernel data structures"
1da177e4 1593
199a9afc
DJ
1594config DEBUG_LIST
1595 bool "Debug linked list manipulation"
4520bcb2 1596 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
199a9afc
DJ
1597 help
1598 Enable this to turn on extended checks in the linked-list
1599 walking routines.
1600
1601 If unsure, say N.
1602
8e18faea 1603config DEBUG_PLIST
b8cfff68
DS
1604 bool "Debug priority linked list manipulation"
1605 depends on DEBUG_KERNEL
1606 help
1607 Enable this to turn on extended checks in the priority-ordered
1608 linked-list (plist) walking routines. This checks the entire
1609 list multiple times during each manipulation.
1610
1611 If unsure, say N.
1612
d6ec0842
JA
1613config DEBUG_SG
1614 bool "Debug SG table operations"
1615 depends on DEBUG_KERNEL
1616 help
1617 Enable this to turn on checks on scatter-gather tables. This can
1618 help find problems with drivers that do not properly initialize
1619 their sg tables.
1620
1621 If unsure, say N.
1622
1b2439db
AV
1623config DEBUG_NOTIFIERS
1624 bool "Debug notifier call chains"
1625 depends on DEBUG_KERNEL
1626 help
1627 Enable this to turn on sanity checking for notifier call chains.
1628 This is most useful for kernel developers to make sure that
1629 modules properly unregister themselves from notifier chains.
1630 This is a relatively cheap check but if you care about maximum
1631 performance, say N.
1632
3be5cbcd
CD
1633config BUG_ON_DATA_CORRUPTION
1634 bool "Trigger a BUG when data corruption is detected"
1635 select DEBUG_LIST
1636 help
1637 Select this option if the kernel should BUG when it encounters
1638 data corruption in kernel memory structures when they get checked
1639 for validity.
1640
1641 If unsure, say N.
1642
54a611b6
LH
1643config DEBUG_MAPLE_TREE
1644 bool "Debug maple trees"
1645 depends on DEBUG_KERNEL
1646 help
1647 Enable maple tree debugging information and extra validations.
1648
1649 If unsure, say N.
1650
3be5cbcd
CD
1651endmenu
1652
e0e81739
DH
1653config DEBUG_CREDENTIALS
1654 bool "Debug credential management"
1655 depends on DEBUG_KERNEL
1656 help
1657 Enable this to turn on some debug checking for credential
1658 management. The additional code keeps track of the number of
1659 pointers from task_structs to any given cred struct, and checks to
1660 see that this number never exceeds the usage count of the cred
1661 struct.
1662
1663 Furthermore, if SELinux is enabled, this also checks that the
1664 security pointer in the cred struct is never seen to be invalid.
1665
1666 If unsure, say N.
1667
43a0a2a7 1668source "kernel/rcu/Kconfig.debug"
2f03e3ca 1669
f303fccb
TH
1670config DEBUG_WQ_FORCE_RR_CPU
1671 bool "Force round-robin CPU selection for unbound work items"
1672 depends on DEBUG_KERNEL
1673 default n
1674 help
1675 Workqueue used to implicitly guarantee that work items queued
1676 without explicit CPU specified are put on the local CPU. This
1677 guarantee is no longer true and while local CPU is still
1678 preferred work items may be put on foreign CPUs. Kernel
1679 parameter "workqueue.debug_force_rr_cpu" is added to force
1680 round-robin CPU selection to flush out usages which depend on the
1681 now broken guarantee. This config option enables the debug
1682 feature by default. When enabled, memory and cache locality will
1683 be impacted.
1684
757c989b
TG
1685config CPU_HOTPLUG_STATE_CONTROL
1686 bool "Enable CPU hotplug state control"
1687 depends on DEBUG_KERNEL
1688 depends on HOTPLUG_CPU
1689 default n
1690 help
1691 Allows to write steps between "offline" and "online" to the CPUs
1692 sysfs target file so states can be stepped granular. This is a debug
1693 option for now as the hotplug machinery cannot be stopped and
1694 restarted at arbitrary points yet.
1695
1696 Say N if your are unsure.
1697
09a74952
CD
1698config LATENCYTOP
1699 bool "Latency measuring infrastructure"
1700 depends on DEBUG_KERNEL
1701 depends on STACKTRACE_SUPPORT
1702 depends on PROC_FS
7d37cb2c 1703 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
09a74952
CD
1704 select KALLSYMS
1705 select KALLSYMS_ALL
1706 select STACKTRACE
1707 select SCHEDSTATS
09a74952
CD
1708 help
1709 Enable this option if you want to use the LatencyTOP tool
1710 to find out which userspace is blocking on what kernel operations.
1711
1712source "kernel/trace/Kconfig"
1713
1714config PROVIDE_OHCI1394_DMA_INIT
1715 bool "Remote debugging over FireWire early on boot"
1716 depends on PCI && X86
1717 help
1718 If you want to debug problems which hang or crash the kernel early
1719 on boot and the crashing machine has a FireWire port, you can use
1720 this feature to remotely access the memory of the crashed machine
1721 over FireWire. This employs remote DMA as part of the OHCI1394
1722 specification which is now the standard for FireWire controllers.
1723
1724 With remote DMA, you can monitor the printk buffer remotely using
1725 firescope and access all memory below 4GB using fireproxy from gdb.
1726 Even controlling a kernel debugger is possible using remote DMA.
1727
1728 Usage:
1729
1730 If ohci1394_dma=early is used as boot parameter, it will initialize
1731 all OHCI1394 controllers which are found in the PCI config space.
1732
1733 As all changes to the FireWire bus such as enabling and disabling
1734 devices cause a bus reset and thereby disable remote DMA for all
1735 devices, be sure to have the cable plugged and FireWire enabled on
1736 the debugging host before booting the debug target for debugging.
1737
1738 This code (~1k) is freed after boot. By then, the firewire stack
1739 in charge of the OHCI-1394 controllers should be used instead.
1740
a74e2a22 1741 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
09a74952 1742
045f6d79
CD
1743source "samples/Kconfig"
1744
1745config ARCH_HAS_DEVMEM_IS_ALLOWED
1746 bool
1747
1748config STRICT_DEVMEM
1749 bool "Filter access to /dev/mem"
1750 depends on MMU && DEVMEM
527701ed 1751 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
045f6d79
CD
1752 default y if PPC || X86 || ARM64
1753 help
1754 If this option is disabled, you allow userspace (root) access to all
1755 of memory, including kernel and userspace memory. Accidental
1756 access to this is obviously disastrous, but specific access can
1757 be used by people debugging the kernel. Note that with PAT support
1758 enabled, even in this case there are restrictions on /dev/mem
1759 use due to the cache aliasing requirements.
1760
1761 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1762 file only allows userspace access to PCI space and the BIOS code and
1763 data regions. This is sufficient for dosemu and X and all common
1764 users of /dev/mem.
1765
1766 If in doubt, say Y.
1767
1768config IO_STRICT_DEVMEM
1769 bool "Filter I/O access to /dev/mem"
1770 depends on STRICT_DEVMEM
1771 help
1772 If this option is disabled, you allow userspace (root) access to all
1773 io-memory regardless of whether a driver is actively using that
1774 range. Accidental access to this is obviously disastrous, but
1775 specific access can be used by people debugging kernel drivers.
1776
1777 If this option is switched on, the /dev/mem file only allows
1778 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1779 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1780 if the driver using a given range cannot be disabled.
1781
1782 If in doubt, say Y.
1783
1784menu "$(SRCARCH) Debugging"
1785
1786source "arch/$(SRCARCH)/Kconfig.debug"
1787
1788endmenu
1789
1790menu "Kernel Testing and Coverage"
1791
09a74952
CD
1792source "lib/kunit/Kconfig"
1793
8d438288
AM
1794config NOTIFIER_ERROR_INJECTION
1795 tristate "Notifier error injection"
1796 depends on DEBUG_KERNEL
1797 select DEBUG_FS
1798 help
e41e85cc 1799 This option provides the ability to inject artificial errors to
8d438288
AM
1800 specified notifier chain callbacks. It is useful to test the error
1801 handling of notifier call chain failures.
1802
1803 Say N if unsure.
1804
048b9c35
AM
1805config PM_NOTIFIER_ERROR_INJECT
1806 tristate "PM notifier error injection module"
1807 depends on PM && NOTIFIER_ERROR_INJECTION
1808 default m if PM_DEBUG
1809 help
e41e85cc 1810 This option provides the ability to inject artificial errors to
048b9c35
AM
1811 PM notifier chain callbacks. It is controlled through debugfs
1812 interface /sys/kernel/debug/notifier-error-inject/pm
1813
1814 If the notifier call chain should be failed with some events
1815 notified, write the error code to "actions/<notifier event>/error".
1816
1817 Example: Inject PM suspend error (-12 = -ENOMEM)
1818
1819 # cd /sys/kernel/debug/notifier-error-inject/pm/
1820 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1821 # echo mem > /sys/power/state
1822 bash: echo: write error: Cannot allocate memory
1823
1824 To compile this code as a module, choose M here: the module will
1825 be called pm-notifier-error-inject.
1826
1827 If unsure, say N.
1828
d526e85f
BH
1829config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1830 tristate "OF reconfig notifier error injection module"
1831 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dd 1832 help
e41e85cc 1833 This option provides the ability to inject artificial errors to
d526e85f 1834 OF reconfig notifier chain callbacks. It is controlled
08dfb4dd 1835 through debugfs interface under
d526e85f 1836 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
08dfb4dd
AM
1837
1838 If the notifier call chain should be failed with some events
1839 notified, write the error code to "actions/<notifier event>/error".
1840
1841 To compile this code as a module, choose M here: the module will
e12a95f4 1842 be called of-reconfig-notifier-error-inject.
08dfb4dd
AM
1843
1844 If unsure, say N.
1845
02fff96a
NA
1846config NETDEV_NOTIFIER_ERROR_INJECT
1847 tristate "Netdev notifier error injection module"
1848 depends on NET && NOTIFIER_ERROR_INJECTION
1849 help
1850 This option provides the ability to inject artificial errors to
1851 netdevice notifier chain callbacks. It is controlled through debugfs
1852 interface /sys/kernel/debug/notifier-error-inject/netdev
1853
1854 If the notifier call chain should be failed with some events
1855 notified, write the error code to "actions/<notifier event>/error".
1856
1857 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1858
1859 # cd /sys/kernel/debug/notifier-error-inject/netdev
1860 # echo -22 > actions/NETDEV_CHANGEMTU/error
1861 # ip link set eth0 mtu 1024
1862 RTNETLINK answers: Invalid argument
1863
1864 To compile this code as a module, choose M here: the module will
1865 be called netdev-notifier-error-inject.
1866
1867 If unsure, say N.
1868
f1b4bd06
MP
1869config FUNCTION_ERROR_INJECTION
1870 def_bool y
1871 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1872
6ff1cb35 1873config FAULT_INJECTION
1ab8509a
AM
1874 bool "Fault-injection framework"
1875 depends on DEBUG_KERNEL
329409ae
AM
1876 help
1877 Provide fault-injection framework.
1878 For more details, see Documentation/fault-injection/.
6ff1cb35 1879
8a8b6502 1880config FAILSLAB
1ab8509a
AM
1881 bool "Fault-injection capability for kmalloc"
1882 depends on FAULT_INJECTION
773ff60e 1883 depends on SLAB || SLUB
8a8b6502 1884 help
1ab8509a 1885 Provide fault-injection capability for kmalloc.
8a8b6502 1886
933e312e 1887config FAIL_PAGE_ALLOC
29b46fa3 1888 bool "Fault-injection capability for alloc_pages()"
1ab8509a 1889 depends on FAULT_INJECTION
933e312e 1890 help
1ab8509a 1891 Provide fault-injection capability for alloc_pages().
933e312e 1892
2c739ced
AL
1893config FAULT_INJECTION_USERCOPY
1894 bool "Fault injection capability for usercopy functions"
1895 depends on FAULT_INJECTION
1896 help
1897 Provides fault-injection capability to inject failures
1898 in usercopy functions (copy_from_user(), get_user(), ...).
1899
c17bb495 1900config FAIL_MAKE_REQUEST
86327d19 1901 bool "Fault-injection capability for disk IO"
581d4e28 1902 depends on FAULT_INJECTION && BLOCK
c17bb495 1903 help
1ab8509a 1904 Provide fault-injection capability for disk IO.
c17bb495 1905
581d4e28 1906config FAIL_IO_TIMEOUT
f4d01439 1907 bool "Fault-injection capability for faking disk interrupts"
581d4e28
JA
1908 depends on FAULT_INJECTION && BLOCK
1909 help
1910 Provide fault-injection capability on end IO handling. This
1911 will make the block layer "forget" an interrupt as configured,
1912 thus exercising the error handling.
1913
1914 Only works with drivers that use the generic timeout handling,
9dbbc3b9 1915 for others it won't do anything.
581d4e28 1916
ab51fbab
DB
1917config FAIL_FUTEX
1918 bool "Fault-injection capability for futexes"
1919 select DEBUG_FS
1920 depends on FAULT_INJECTION && FUTEX
1921 help
1922 Provide fault-injection capability for futexes.
1923
f1b4bd06
MP
1924config FAULT_INJECTION_DEBUG_FS
1925 bool "Debugfs entries for fault-injection capabilities"
1926 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1927 help
1928 Enable configuration of fault-injection capabilities via debugfs.
1929
4b1a29a7
MH
1930config FAIL_FUNCTION
1931 bool "Fault-injection capability for functions"
1932 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1933 help
1934 Provide function-based fault-injection capability.
1935 This will allow you to override a specific function with a return
1936 with given return value. As a result, function caller will see
1937 an error value and have to handle it. This is useful to test the
1938 error handling in various subsystems.
1939
f1b4bd06
MP
1940config FAIL_MMC_REQUEST
1941 bool "Fault-injection capability for MMC IO"
1942 depends on FAULT_INJECTION_DEBUG_FS && MMC
6ff1cb35 1943 help
f1b4bd06
MP
1944 Provide fault-injection capability for MMC IO.
1945 This will make the mmc core return data errors. This is
1946 useful to test the error handling in the mmc block device
1947 and to test how the mmc host driver handles retries from
1948 the block device.
1df49008 1949
c782af25
CL
1950config FAIL_SUNRPC
1951 bool "Fault-injection capability for SunRPC"
1952 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1953 help
1954 Provide fault-injection capability for SunRPC and
1955 its consumers.
1956
1df49008
AM
1957config FAULT_INJECTION_STACKTRACE_FILTER
1958 bool "stacktrace filter for fault-injection capabilities"
1959 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
6d690dca 1960 depends on !X86_64
1df49008 1961 select STACKTRACE
7d37cb2c 1962 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1df49008
AM
1963 help
1964 Provide stacktrace filter for fault-injection capabilities
267c4025 1965
09a74952
CD
1966config ARCH_HAS_KCOV
1967 bool
cc3fa840 1968 help
09a74952
CD
1969 An architecture should select this when it can successfully
1970 build and run with CONFIG_KCOV. This typically requires
1971 disabling instrumentation for some early boot code.
cc3fa840 1972
09a74952
CD
1973config CC_HAS_SANCOV_TRACE_PC
1974 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
cc3fa840 1975
cc3fa840 1976
09a74952
CD
1977config KCOV
1978 bool "Code coverage for fuzzing"
1979 depends on ARCH_HAS_KCOV
1980 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
22102f45 1981 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
bece04b5 1982 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
09a74952
CD
1983 select DEBUG_FS
1984 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
22102f45 1985 select OBJTOOL if HAVE_NOINSTR_HACK
09a74952
CD
1986 help
1987 KCOV exposes kernel code coverage information in a form suitable
1988 for coverage-guided fuzzing (randomized testing).
cc3fa840 1989
09a74952
CD
1990 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1991 different machines and across reboots. If you need stable PC values,
1992 disable RANDOMIZE_BASE.
cc3fa840 1993
09a74952 1994 For more details, see Documentation/dev-tools/kcov.rst.
cc3fa840 1995
09a74952
CD
1996config KCOV_ENABLE_COMPARISONS
1997 bool "Enable comparison operands collection by KCOV"
1998 depends on KCOV
1999 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2000 help
2001 KCOV also exposes operands of every comparison in the instrumented
2002 code along with operand sizes and PCs of the comparison instructions.
2003 These operands can be used by fuzzing engines to improve the quality
2004 of fuzzing coverage.
cc3fa840 2005
09a74952
CD
2006config KCOV_INSTRUMENT_ALL
2007 bool "Instrument all code by default"
2008 depends on KCOV
2009 default y
2010 help
2011 If you are doing generic system call fuzzing (like e.g. syzkaller),
2012 then you will want to instrument the whole kernel and you should
2013 say y here. If you are doing more targeted fuzzing (like e.g.
2014 filesystem fuzzing with AFL) then you will want to enable coverage
2015 for more specific subsets of files, and should say n here.
84bc809e 2016
5ff3b30a
AK
2017config KCOV_IRQ_AREA_SIZE
2018 hex "Size of interrupt coverage collection area in words"
2019 depends on KCOV
2020 default 0x40000
2021 help
2022 KCOV uses preallocated per-cpu areas to collect coverage from
2023 soft interrupts. This specifies the size of those areas in the
2024 number of unsigned long words.
2025
d3deafaa
VL
2026menuconfig RUNTIME_TESTING_MENU
2027 bool "Runtime Testing"
908009e8 2028 def_bool y
d3deafaa
VL
2029
2030if RUNTIME_TESTING_MENU
881c5149
DH
2031
2032config LKDTM
2033 tristate "Linux Kernel Dump Test Tool Module"
2034 depends on DEBUG_FS
881c5149
DH
2035 help
2036 This module enables testing of the different dumping mechanisms by
2037 inducing system failures at predefined crash points.
2038 If you don't need it: say N
2039 Choose M here to compile this code as a module. The module will be
2040 called lkdtm.
2041
2042 Documentation on how to use the module can be found in
10ffebbe 2043 Documentation/fault-injection/provoke-crashes.rst
881c5149 2044
d3c0ca49
SV
2045config CPUMASK_KUNIT_TEST
2046 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
c41e8866
SV
2047 depends on KUNIT
2048 default KUNIT_ALL_TESTS
2049 help
2050 Enable to turn on cpumask tests, running at boot or module load time.
2051
d3c0ca49
SV
2052 For more information on KUnit and unit tests in general, please refer
2053 to the KUnit documentation in Documentation/dev-tools/kunit/.
2054
c41e8866
SV
2055 If unsure, say N.
2056
881c5149 2057config TEST_LIST_SORT
ebd09577
DL
2058 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2059 depends on KUNIT
2060 default KUNIT_ALL_TESTS
881c5149
DH
2061 help
2062 Enable this to turn on 'list_sort()' function test. This test is
e327fd7c
GU
2063 executed only once during system boot (so affects only boot time),
2064 or at module load time.
881c5149
DH
2065
2066 If unsure, say N.
2067
6e24628d
IR
2068config TEST_MIN_HEAP
2069 tristate "Min heap test"
2070 depends on DEBUG_KERNEL || m
2071 help
2072 Enable this to turn on min heap function tests. This test is
2073 executed only once during system boot (so affects only boot time),
2074 or at module load time.
2075
2076 If unsure, say N.
2077
c5adae95 2078config TEST_SORT
36f33b56
DL
2079 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2080 depends on KUNIT
2081 default KUNIT_ALL_TESTS
c5adae95 2082 help
5c4e6798
GU
2083 This option enables the self-test function of 'sort()' at boot,
2084 or at module load time.
c5adae95
KF
2085
2086 If unsure, say N.
2087
5086ea4b
MR
2088config TEST_DIV64
2089 tristate "64bit/32bit division and modulo test"
2090 depends on DEBUG_KERNEL || m
2091 help
2092 Enable this to turn on 'do_div()' function test. This test is
2093 executed only once during system boot (so affects only boot time),
2094 or at module load time.
2095
2096 If unsure, say N.
2097
881c5149 2098config KPROBES_SANITY_TEST
dcbb2ee2 2099 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
881c5149
DH
2100 depends on DEBUG_KERNEL
2101 depends on KPROBES
e44e81c5 2102 depends on KUNIT
dcbb2ee2 2103 default KUNIT_ALL_TESTS
881c5149
DH
2104 help
2105 This option provides for testing basic kprobes functionality on
5a6cf77f 2106 boot. Samples of kprobe and kretprobe are inserted and
881c5149
DH
2107 verified for functionality.
2108
2109 Say N if you are unsure.
2110
f4616fab
MH
2111config FPROBE_SANITY_TEST
2112 bool "Self test for fprobe"
2113 depends on DEBUG_KERNEL
2114 depends on FPROBE
2115 depends on KUNIT=y
2116 help
2117 This option will enable testing the fprobe when the system boot.
2118 A series of tests are made to verify that the fprobe is functioning
2119 properly.
2120
2121 Say N if you are unsure.
2122
881c5149
DH
2123config BACKTRACE_SELF_TEST
2124 tristate "Self test for the backtrace code"
2125 depends on DEBUG_KERNEL
881c5149
DH
2126 help
2127 This option provides a kernel module that can be used to test
2128 the kernel stack backtrace code. This option is not useful
2129 for distributions or general kernels, but only for kernel
2130 developers working on architecture code.
2131
2132 Note that if you want to also test saved backtraces, you will
2133 have to enable STACKTRACE as well.
2134
2135 Say N if you are unsure.
2136
914a7b50
ED
2137config TEST_REF_TRACKER
2138 tristate "Self test for reference tracker"
2139 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2140 select REF_TRACKER
2141 help
2142 This option provides a kernel module performing tests
2143 using reference tracker infrastructure.
2144
2145 Say N if you are unsure.
2146
910a742d
ML
2147config RBTREE_TEST
2148 tristate "Red-Black tree test"
7c993e11 2149 depends on DEBUG_KERNEL
910a742d
ML
2150 help
2151 A benchmark measuring the performance of the rbtree library.
2152 Also includes rbtree invariant checks.
2153
4b4f3acc
FB
2154config REED_SOLOMON_TEST
2155 tristate "Reed-Solomon library test"
2156 depends on DEBUG_KERNEL || m
2157 select REED_SOLOMON
2158 select REED_SOLOMON_ENC16
2159 select REED_SOLOMON_DEC16
2160 help
2161 This option enables the self-test function of rslib at boot,
2162 or at module load time.
2163
2164 If unsure, say N.
2165
fff3fd8a
ML
2166config INTERVAL_TREE_TEST
2167 tristate "Interval tree test"
0f789b67 2168 depends on DEBUG_KERNEL
a88cc108 2169 select INTERVAL_TREE
fff3fd8a
ML
2170 help
2171 A benchmark measuring the performance of the interval tree library
2172
623fd807
GT
2173config PERCPU_TEST
2174 tristate "Per cpu operations test"
2175 depends on m && DEBUG_KERNEL
2176 help
2177 Enable this option to build test module which validates per-cpu
2178 operations.
2179
2180 If unsure, say N.
2181
881c5149 2182config ATOMIC64_SELFTEST
55ded955 2183 tristate "Perform an atomic64_t self-test"
881c5149 2184 help
55ded955
GU
2185 Enable this option to test the atomic64_t functions at boot or
2186 at module load time.
881c5149
DH
2187
2188 If unsure, say N.
2189
2190config ASYNC_RAID6_TEST
2191 tristate "Self test for hardware accelerated raid6 recovery"
2192 depends on ASYNC_RAID6_RECOV
2193 select ASYNC_MEMCPY
a7f7f624 2194 help
881c5149
DH
2195 This is a one-shot self test that permutes through the
2196 recovery of all the possible two disk failure scenarios for a
2197 N-disk array. Recovery is performed with the asynchronous
2198 raid6 recovery routines, and will optionally use an offload
2199 engine if one is available.
2200
2201 If unsure, say N.
2202
64d1d77a
AS
2203config TEST_HEXDUMP
2204 tristate "Test functions located in the hexdump module at runtime"
2205
b2ff70a0
MC
2206config STRING_SELFTEST
2207 tristate "Test string functions at runtime"
2208
881c5149
DH
2209config TEST_STRING_HELPERS
2210 tristate "Test functions located in the string_helpers module at runtime"
2211
0b0600c8
TH
2212config TEST_STRSCPY
2213 tristate "Test strscpy*() family of functions at runtime"
2214
881c5149
DH
2215config TEST_KSTRTOX
2216 tristate "Test kstrto*() family of functions at runtime"
2217
707cc728
RV
2218config TEST_PRINTF
2219 tristate "Test printf() family of functions at runtime"
2220
50f530e1
RF
2221config TEST_SCANF
2222 tristate "Test scanf() family of functions at runtime"
2223
5fd003f5
DD
2224config TEST_BITMAP
2225 tristate "Test bitmap_*() family of functions at runtime"
5fd003f5
DD
2226 help
2227 Enable this option to test the bitmap functions at boot.
2228
2229 If unsure, say N.
2230
cfaff0e5
AS
2231config TEST_UUID
2232 tristate "Test functions located in the uuid module at runtime"
2233
ad3d6c72
MW
2234config TEST_XARRAY
2235 tristate "Test the XArray code at runtime"
2236
7e1e7763 2237config TEST_RHASHTABLE
9d6dbe1b 2238 tristate "Perform selftest on resizable hash table"
7e1e7763
TG
2239 help
2240 Enable this option to test the rhashtable functions at boot.
2241
2242 If unsure, say N.
2243
88168bf3
IB
2244config TEST_SIPHASH
2245 tristate "Perform selftest on siphash functions"
468a9428 2246 help
88168bf3
IB
2247 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2248 functions on boot (or module load).
468a9428
GS
2249
2250 This is intended to help people writing architecture-specific
2251 optimized versions. If unsure, say N.
2252
8ab8ba38
MW
2253config TEST_IDA
2254 tristate "Perform selftest on IDA functions"
2255
44091d29
JP
2256config TEST_PARMAN
2257 tristate "Perform selftest on priority array manager"
44091d29
JP
2258 depends on PARMAN
2259 help
2260 Enable this option to test priority array manager on boot
2261 (or module load).
2262
2263 If unsure, say N.
2264
6aed82de
DL
2265config TEST_IRQ_TIMINGS
2266 bool "IRQ timings selftest"
2267 depends on IRQ_TIMINGS
2268 help
2269 Enable this option to test the irq timings code on boot.
2270
2271 If unsure, say N.
2272
8a6f0b47 2273config TEST_LKM
93e9ef83 2274 tristate "Test module loading with 'hello world' module"
93e9ef83
KC
2275 depends on m
2276 help
2277 This builds the "test_module" module that emits "Hello, world"
2278 on printk when loaded. It is designed to be used for basic
2279 evaluation of the module loading subsystem (for example when
2280 validating module verification). It lacks any extra dependencies,
2281 and will not normally be loaded by the system unless explicitly
2282 requested by name.
2283
2284 If unsure, say N.
2285
c348c163 2286config TEST_BITOPS
6af132f3 2287 tristate "Test module for compilation of bitops operations"
c348c163
JB
2288 depends on m
2289 help
2290 This builds the "test_bitops" module that is much like the
2291 TEST_LKM module except that it does a basic exercise of the
6af132f3
WY
2292 set/clear_bit macros and get_count_order/long to make sure there are
2293 no compiler warnings from C=1 sparse checker or -Wextra
2294 compilations. It has no dependencies and doesn't run or load unless
2295 explicitly requested by name. for example: modprobe test_bitops.
c348c163
JB
2296
2297 If unsure, say N.
2298
3f21a6b7
URS
2299config TEST_VMALLOC
2300 tristate "Test module for stress/performance analysis of vmalloc allocator"
2301 default n
2302 depends on MMU
2303 depends on m
2304 help
2305 This builds the "test_vmalloc" module that should be used for
2306 stress and performance analysis. So, any new change for vmalloc
2307 subsystem can be evaluated from performance and stability point
2308 of view.
2309
2310 If unsure, say N.
2311
3e2a4c18
KC
2312config TEST_USER_COPY
2313 tristate "Test user/kernel boundary protections"
3e2a4c18
KC
2314 depends on m
2315 help
2316 This builds the "test_user_copy" module that runs sanity checks
2317 on the copy_to/from_user infrastructure, making sure basic
2318 user/kernel boundary testing is working. If it fails to load,
2319 a regression has been detected in the user/kernel memory boundary
2320 protections.
2321
2322 If unsure, say N.
2323
64a8946b
AS
2324config TEST_BPF
2325 tristate "Test BPF filter functionality"
98920ba6 2326 depends on m && NET
64a8946b
AS
2327 help
2328 This builds the "test_bpf" module that runs various test vectors
2329 against the BPF interpreter or BPF JIT compiler depending on the
2330 current setting. This is in particular useful for BPF JIT compiler
2331 development, but also to run regression tests against changes in
3c731eba
AS
2332 the interpreter code. It also enables test stubs for eBPF maps and
2333 verifier used by user space verifier testsuite.
64a8946b
AS
2334
2335 If unsure, say N.
2336
509e56b3
MB
2337config TEST_BLACKHOLE_DEV
2338 tristate "Test blackhole netdev functionality"
2339 depends on m && NET
2340 help
2341 This builds the "test_blackhole_dev" module that validates the
2342 data path through this blackhole netdev.
2343
2344 If unsure, say N.
2345
dceeb3e7 2346config FIND_BIT_BENCHMARK
4441fca0 2347 tristate "Test find_bit functions"
4441fca0
YN
2348 help
2349 This builds the "test_find_bit" module that measure find_*_bit()
2350 functions performance.
2351
2352 If unsure, say N.
2353
0a8adf58
KC
2354config TEST_FIRMWARE
2355 tristate "Test firmware loading via userspace interface"
0a8adf58
KC
2356 depends on FW_LOADER
2357 help
2358 This builds the "test_firmware" module that creates a userspace
2359 interface for testing firmware loading. This can be used to
2360 control the triggering of firmware loading without needing an
2361 actual firmware-using device. The contents can be rechecked by
2362 userspace.
2363
2364 If unsure, say N.
2365
9308f2f9
LR
2366config TEST_SYSCTL
2367 tristate "sysctl test driver"
9308f2f9
LR
2368 depends on PROC_SYSCTL
2369 help
2370 This builds the "test_sysctl" module. This driver enables to test the
2371 proc sysctl interfaces available to drivers safely without affecting
2372 production knobs which might alter system functionality.
2373
2374 If unsure, say N.
2375
d2585f51 2376config BITFIELD_KUNIT
dcbb2ee2 2377 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
d2585f51 2378 depends on KUNIT
dcbb2ee2 2379 default KUNIT_ALL_TESTS
d2585f51
VMI
2380 help
2381 Enable this option to test the bitfield functions at boot.
2382
2383 KUnit tests run during boot and output the results to the debug log
2384 in TAP format (http://testanything.org/). Only useful for kernel devs
2385 running the KUnit test harness, and not intended for inclusion into a
2386 production build.
2387
2388 For more information on KUnit and unit tests in general please refer
2389 to the KUnit documentation in Documentation/dev-tools/kunit/.
2390
2391 If unsure, say N.
2392
0acc968f
IB
2393config HASH_KUNIT_TEST
2394 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2395 depends on KUNIT
2396 default KUNIT_ALL_TESTS
2397 help
2398 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2399 integer (<linux/hash.h>) hash functions on boot.
2400
2401 KUnit tests run during boot and output the results to the debug log
2402 in TAP format (https://testanything.org/). Only useful for kernel devs
2403 running the KUnit test harness, and not intended for inclusion into a
2404 production build.
2405
2406 For more information on KUnit and unit tests in general please refer
2407 to the KUnit documentation in Documentation/dev-tools/kunit/.
2408
2409 This is intended to help people writing architecture-specific
2410 optimized versions. If unsure, say N.
2411
5df38ca6 2412config RESOURCE_KUNIT_TEST
dcbb2ee2 2413 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
5df38ca6 2414 depends on KUNIT
dcbb2ee2 2415 default KUNIT_ALL_TESTS
5df38ca6
AS
2416 help
2417 This builds the resource API unit test.
2418 Tests the logic of API provided by resource.c and ioport.h.
2419 For more information on KUnit and unit tests in general please refer
2420 to the KUnit documentation in Documentation/dev-tools/kunit/.
2421
2422 If unsure, say N.
2423
2cb80dbb 2424config SYSCTL_KUNIT_TEST
5f215aab 2425 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2cb80dbb 2426 depends on KUNIT
5f215aab 2427 default KUNIT_ALL_TESTS
2cb80dbb
IZ
2428 help
2429 This builds the proc sysctl unit test, which runs on boot.
2430 Tests the API contract and implementation correctness of sysctl.
2431 For more information on KUnit and unit tests in general please refer
2432 to the KUnit documentation in Documentation/dev-tools/kunit/.
2433
2434 If unsure, say N.
2435
ea2dd7c0 2436config LIST_KUNIT_TEST
5f215aab 2437 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
ea2dd7c0 2438 depends on KUNIT
5f215aab 2439 default KUNIT_ALL_TESTS
ea2dd7c0
DG
2440 help
2441 This builds the linked list KUnit test suite.
2442 It tests that the API and basic functionality of the list_head type
2443 and associated macros.
2444
2445 KUnit tests run during boot and output the results to the debug log
d89775fc 2446 in TAP format (https://testanything.org/). Only useful for kernel devs
ea2dd7c0
DG
2447 running the KUnit test harness, and not intended for inclusion into a
2448 production build.
2449
2450 For more information on KUnit and unit tests in general please refer
2451 to the KUnit documentation in Documentation/dev-tools/kunit/.
2452
2453 If unsure, say N.
2454
33d599f0
MV
2455config LINEAR_RANGES_TEST
2456 tristate "KUnit test for linear_ranges"
2457 depends on KUNIT
2458 select LINEAR_RANGES
2459 help
2460 This builds the linear_ranges unit test, which runs on boot.
2461 Tests the linear_ranges logic correctness.
2462 For more information on KUnit and unit tests in general please refer
7546861a
AS
2463 to the KUnit documentation in Documentation/dev-tools/kunit/.
2464
2465 If unsure, say N.
2466
2467config CMDLINE_KUNIT_TEST
dcbb2ee2 2468 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
7546861a 2469 depends on KUNIT
dcbb2ee2 2470 default KUNIT_ALL_TESTS
7546861a
AS
2471 help
2472 This builds the cmdline API unit test.
2473 Tests the logic of API provided by cmdline.c.
2474 For more information on KUnit and unit tests in general please refer
33d599f0
MV
2475 to the KUnit documentation in Documentation/dev-tools/kunit/.
2476
2477 If unsure, say N.
2478
6d511020 2479config BITS_TEST
dcbb2ee2 2480 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
6d511020 2481 depends on KUNIT
dcbb2ee2 2482 default KUNIT_ALL_TESTS
6d511020
RF
2483 help
2484 This builds the bits unit test.
2485 Tests the logic of macros defined in bits.h.
2486 For more information on KUnit and unit tests in general please refer
2487 to the KUnit documentation in Documentation/dev-tools/kunit/.
2488
2489 If unsure, say N.
2490
1f9f78b1
OG
2491config SLUB_KUNIT_TEST
2492 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2493 depends on SLUB_DEBUG && KUNIT
2494 default KUNIT_ALL_TESTS
2495 help
2496 This builds SLUB allocator unit test.
2497 Tests SLUB cache debugging functionality.
2498 For more information on KUnit and unit tests in general please refer
2499 to the KUnit documentation in Documentation/dev-tools/kunit/.
2500
2501 If unsure, say N.
2502
b6c75c4a
TP
2503config RATIONAL_KUNIT_TEST
2504 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
8ba739ed 2505 depends on KUNIT && RATIONAL
b6c75c4a
TP
2506 default KUNIT_ALL_TESTS
2507 help
2508 This builds the rational math unit test.
2509 For more information on KUnit and unit tests in general please refer
2510 to the KUnit documentation in Documentation/dev-tools/kunit/.
2511
2512 If unsure, say N.
2513
bb95ebbe
KC
2514config MEMCPY_KUNIT_TEST
2515 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2516 depends on KUNIT
2517 default KUNIT_ALL_TESTS
2518 help
2519 Builds unit tests for memcpy(), memmove(), and memset() functions.
2520 For more information on KUnit and unit tests in general please refer
2521 to the KUnit documentation in Documentation/dev-tools/kunit/.
2522
2523 If unsure, say N.
2524
addbeea6
BVA
2525config IS_SIGNED_TYPE_KUNIT_TEST
2526 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2527 depends on KUNIT
2528 default KUNIT_ALL_TESTS
2529 help
2530 Builds unit tests for the is_signed_type() macro.
2531
2532 For more information on KUnit and unit tests in general please refer
2533 to the KUnit documentation in Documentation/dev-tools/kunit/.
2534
2535 If unsure, say N.
2536
617f55e2
KC
2537config OVERFLOW_KUNIT_TEST
2538 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2539 depends on KUNIT
2540 default KUNIT_ALL_TESTS
2541 help
2542 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2543 related functions.
2544
2545 For more information on KUnit and unit tests in general please refer
2546 to the KUnit documentation in Documentation/dev-tools/kunit/.
2547
2548 If unsure, say N.
2549
02788ebc
KC
2550config STACKINIT_KUNIT_TEST
2551 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2552 depends on KUNIT
2553 default KUNIT_ALL_TESTS
2554 help
2555 Test if the kernel is zero-initializing stack variables and
2556 padding. Coverage is controlled by compiler flags,
2557 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2558 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2559 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2560
875bfd52
KC
2561config FORTIFY_KUNIT_TEST
2562 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2563 depends on KUNIT && FORTIFY_SOURCE
2564 default KUNIT_ALL_TESTS
2565 help
2566 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2567 by the str*() and mem*() family of functions. For testing runtime
2568 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2569
724c299c
ME
2570config HW_BREAKPOINT_KUNIT_TEST
2571 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2572 depends on HAVE_HW_BREAKPOINT
2573 depends on KUNIT=y
2574 default KUNIT_ALL_TESTS
2575 help
2576 Tests for hw_breakpoint constraints accounting.
2577
2578 If unsure, say N.
2579
e704f93a
DR
2580config TEST_UDELAY
2581 tristate "udelay test driver"
e704f93a
DR
2582 help
2583 This builds the "udelay_test" module that helps to make sure
2584 that udelay() is working properly.
2585
2586 If unsure, say N.
2587
2bf9e0ab
IM
2588config TEST_STATIC_KEYS
2589 tristate "Test static keys"
579e1acb
JB
2590 depends on m
2591 help
2bf9e0ab 2592 Test the static key interfaces.
579e1acb
JB
2593
2594 If unsure, say N.
2595
683263a5
JC
2596config TEST_DYNAMIC_DEBUG
2597 tristate "Test DYNAMIC_DEBUG"
2598 depends on DYNAMIC_DEBUG
2599 help
2600 This module registers a tracer callback to count enabled
2601 pr_debugs in a 'do_debugging' function, then alters their
2602 enablements, calls the function, and compares counts.
2603
2604 If unsure, say N.
2605
d9c6a72d
LR
2606config TEST_KMOD
2607 tristate "kmod stress tester"
d9c6a72d 2608 depends on m
d9c6a72d 2609 depends on NETDEVICES && NET_CORE && INET # for TUN
ae3d6a32 2610 depends on BLOCK
bbd2e05f 2611 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
d9c6a72d
LR
2612 select TEST_LKM
2613 select XFS_FS
2614 select TUN
2615 select BTRFS_FS
2616 help
2617 Test the kernel's module loading mechanism: kmod. kmod implements
2618 support to load modules using the Linux kernel's usermode helper.
2619 This test provides a series of tests against kmod.
2620
2621 Although technically you can either build test_kmod as a module or
2622 into the kernel we disallow building it into the kernel since
2623 it stress tests request_module() and this will very likely cause
2624 some issues by taking over precious threads available from other
2625 module load requests, ultimately this could be fatal.
2626
2627 To run tests run:
2628
2629 tools/testing/selftests/kmod/kmod.sh --help
2630
2631 If unsure, say N.
2632
e4dace36
FF
2633config TEST_DEBUG_VIRTUAL
2634 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2635 depends on DEBUG_VIRTUAL
2636 help
2637 Test the kernel's ability to detect incorrect calls to
2638 virt_to_phys() done against the non-linear part of the
2639 kernel's virtual address map.
2640
2641 If unsure, say N.
2642
ce76d938
AS
2643config TEST_MEMCAT_P
2644 tristate "Test memcat_p() helper function"
2645 help
2646 Test the memcat_p() helper for correctly merging two
2647 pointer arrays together.
2648
2649 If unsure, say N.
2650
a2818ee4
JL
2651config TEST_LIVEPATCH
2652 tristate "Test livepatching"
2653 default n
bae05437 2654 depends on DYNAMIC_DEBUG
a2818ee4
JL
2655 depends on LIVEPATCH
2656 depends on m
2657 help
2658 Test kernel livepatching features for correctness. The tests will
2659 load test modules that will be livepatched in various scenarios.
2660
2661 To run all the livepatching tests:
2662
2663 make -C tools/testing/selftests TARGETS=livepatch run_tests
2664
2665 Alternatively, individual tests may be invoked:
2666
2667 tools/testing/selftests/livepatch/test-callbacks.sh
2668 tools/testing/selftests/livepatch/test-livepatch.sh
2669 tools/testing/selftests/livepatch/test-shadow-vars.sh
2670
2671 If unsure, say N.
2672
0a020d41
JP
2673config TEST_OBJAGG
2674 tristate "Perform selftest on object aggreration manager"
2675 default n
2676 depends on OBJAGG
2677 help
2678 Enable this option to test object aggregation manager on boot
2679 (or module load).
2680
5015a300
AP
2681config TEST_MEMINIT
2682 tristate "Test heap/page initialization"
2683 help
2684 Test if the kernel is zero-initializing heap and page allocations.
2685 This can be useful to test init_on_alloc and init_on_free features.
2686
2687 If unsure, say N.
2688
b2ef9f5a
RC
2689config TEST_HMM
2690 tristate "Test HMM (Heterogeneous Memory Management)"
2691 depends on TRANSPARENT_HUGEPAGE
2692 depends on DEVICE_PRIVATE
2693 select HMM_MIRROR
2694 select MMU_NOTIFIER
2695 help
2696 This is a pseudo device driver solely for testing HMM.
2697 Say M here if you want to build the HMM test module.
2698 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2699
2700 If unsure, say N.
2701
e320d301
MWO
2702config TEST_FREE_PAGES
2703 tristate "Test freeing pages"
2704 help
2705 Test that a memory leak does not occur due to a race between
2706 freeing a block of pages and a speculative page reference.
2707 Loading this module is safe if your kernel has the bug fixed.
2708 If the bug is not fixed, it will leak gigabytes of memory and
2709 probably OOM your system.
2710
4185b3b9
PA
2711config TEST_FPU
2712 tristate "Test floating point operations in kernel space"
2713 depends on X86 && !KCOV_INSTRUMENT_ALL
2714 help
2715 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2716 which will trigger a sequence of floating point operations. This is used
2717 for self-testing floating point control register setting in
2718 kernel_fpu_begin().
2719
2720 If unsure, say N.
2721
1253b9b8
PM
2722config TEST_CLOCKSOURCE_WATCHDOG
2723 tristate "Test clocksource watchdog in kernel space"
2724 depends on CLOCKSOURCE_WATCHDOG
2725 help
2726 Enable this option to create a kernel module that will trigger
2727 a test of the clocksource watchdog. This module may be loaded
2728 via modprobe or insmod in which case it will run upon being
2729 loaded, or it may be built in, in which case it will run
2730 shortly after boot.
2731
2732 If unsure, say N.
2733
d3deafaa 2734endif # RUNTIME_TESTING_MENU
cc3fa840 2735
dce44566
AK
2736config ARCH_USE_MEMTEST
2737 bool
2738 help
2739 An architecture should select this when it uses early_memtest()
2740 during boot process.
2741
cc3fa840
RD
2742config MEMTEST
2743 bool "Memtest"
dce44566 2744 depends on ARCH_USE_MEMTEST
a7f7f624 2745 help
cc3fa840 2746 This option adds a kernel parameter 'memtest', which allows memtest
dce44566 2747 to be set and executed.
cc3fa840
RD
2748 memtest=0, mean disabled; -- default
2749 memtest=1, mean do 1 test pattern;
2750 ...
2751 memtest=17, mean do 17 test patterns.
2752 If you are unsure how to answer this question, answer N.
2753
21266be9 2754
06ec64b8 2755
af9ca6f9
BB
2756config HYPERV_TESTING
2757 bool "Microsoft Hyper-V driver testing"
2758 default n
2759 depends on HYPERV && DEBUG_FS
2760 help
2761 Select this option to enable Hyper-V vmbus testing.
2762
045f6d79
CD
2763endmenu # "Kernel Testing and Coverage"
2764
2f7ab126
MO
2765menu "Rust hacking"
2766
2767config RUST_DEBUG_ASSERTIONS
2768 bool "Debug assertions"
2769 depends on RUST
2770 help
2771 Enables rustc's `-Cdebug-assertions` codegen option.
2772
2773 This flag lets you turn `cfg(debug_assertions)` conditional
2774 compilation on or off. This can be used to enable extra debugging
2775 code in development but not in production. For example, it controls
2776 the behavior of the standard library's `debug_assert!` macro.
2777
2778 Note that this will apply to all Rust code, including `core`.
2779
2780 If unsure, say N.
2781
2782config RUST_OVERFLOW_CHECKS
2783 bool "Overflow checks"
2784 default y
2785 depends on RUST
2786 help
2787 Enables rustc's `-Coverflow-checks` codegen option.
2788
2789 This flag allows you to control the behavior of runtime integer
2790 overflow. When overflow-checks are enabled, a Rust panic will occur
2791 on overflow.
2792
2793 Note that this will apply to all Rust code, including `core`.
2794
2795 If unsure, say Y.
2796
2797endmenu # "Rust"
2798
75442fb0
MCC
2799source "Documentation/Kconfig"
2800
06ec64b8 2801endmenu # Kernel hacking