maple_tree: update copyright dates for test code
[linux-block.git] / lib / Kconfig.debug
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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
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234# Clang is known to generate .{s,u}leb128 with symbol deltas with DWARF5, which
235# some targets may not support: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
236config AS_HAS_NON_CONST_LEB128
237 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
238
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239choice
240 prompt "Debug information"
241 depends on DEBUG_KERNEL
242 help
243 Selecting something other than "None" results in a kernel image
244 that will include debugging info resulting in a larger kernel image.
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245 This adds debug symbols to the kernel and modules (gcc -g), and
246 is needed if you intend to use kernel crashdump or binary object
247 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
6dfc0665 248
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249 Choose which version of DWARF debug info to emit. If unsure,
250 select "Toolchain default".
251
252config DEBUG_INFO_NONE
253 bool "Disable debug information"
254 help
255 Do not build the kernel with debugging information, which will
256 result in a faster and smaller build.
257
258config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
259 bool "Rely on the toolchain's implicit default DWARF version"
260 select DEBUG_INFO
0a6de78c 261 depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
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262 help
263 The implicit default version of DWARF debug info produced by a
264 toolchain changes over time.
265
266 This can break consumers of the debug info that haven't upgraded to
267 support newer revisions, and prevent testing newer versions, but
268 those should be less common scenarios.
269
270config DEBUG_INFO_DWARF4
271 bool "Generate DWARF Version 4 debuginfo"
272 select DEBUG_INFO
4f001a21 273 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
f9b3cd24 274 help
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275 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
276 if using clang without clang's integrated assembler, and gdb 7.0+.
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277
278 If you have consumers of DWARF debug info that are not ready for
279 newer revisions of DWARF, you may wish to choose this or have your
280 config select this.
281
282config DEBUG_INFO_DWARF5
283 bool "Generate DWARF Version 5 debuginfo"
284 select DEBUG_INFO
0a6de78c 285 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
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286 help
287 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
288 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
289 draft features until 7.0), and gdb 8.0+.
290
291 Changes to the structure of debug info in Version 5 allow for around
292 15-18% savings in resulting image and debug info section sizes as
293 compared to DWARF Version 4. DWARF Version 5 standardizes previous
294 extensions such as accelerators for symbol indexing and the format
295 for fission (.dwo/.dwp) files. Users may not want to select this
296 config if they rely on tooling that has not yet been updated to
297 support DWARF Version 5.
298
299endchoice # "Debug information"
6dfc0665 300
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301if DEBUG_INFO
302
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303config DEBUG_INFO_REDUCED
304 bool "Reduce debugging information"
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305 help
306 If you say Y here gcc is instructed to generate less debugging
307 information for structure types. This means that tools that
308 need full debugging information (like kgdb or systemtap) won't
309 be happy. But if you merely need debugging information to
310 resolve line numbers there is no loss. Advantage is that
311 build directory object sizes shrink dramatically over a full
312 DEBUG_INFO build and compile times are reduced too.
313 Only works with newer gcc versions.
314
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315config DEBUG_INFO_COMPRESSED
316 bool "Compressed debugging information"
10e68b02 317 depends on $(cc-option,-gz=zlib)
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318 depends on $(ld-option,--compress-debug-sections=zlib)
319 help
320 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
321 5.0+, binutils 2.26+, and zlib.
322
323 Users of dpkg-deb via scripts/package/builddeb may find an increase in
324 size of their debug .deb packages with this config set, due to the
325 debug info being compressed with zlib, then the object files being
326 recompressed with a different compression scheme. But this is still
327 preferable to setting $KDEB_COMPRESS to "none" which would be even
328 larger.
329
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330config DEBUG_INFO_SPLIT
331 bool "Produce split debuginfo in .dwo files"
9d937444 332 depends on $(cc-option,-gsplit-dwarf)
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333 help
334 Generate debug info into separate .dwo files. This significantly
335 reduces the build directory size for builds with DEBUG_INFO,
336 because it stores the information only once on disk in .dwo
337 files instead of multiple times in object files and executables.
338 In addition the debug information is also compressed.
339
340 Requires recent gcc (4.7+) and recent gdb/binutils.
341 Any tool that packages or reads debug information would need
342 to know about the .dwo files and include them.
343 Incompatible with older versions of ccache.
344
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345config DEBUG_INFO_BTF
346 bool "Generate BTF typeinfo"
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347 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
348 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
d9847eb8 349 depends on BPF_SYSCALL
52deda95 350 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
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351 help
352 Generate deduplicated BTF type information from DWARF debug info.
353 Turning this on expects presence of pahole tool, which will convert
354 DWARF type info into equivalent deduplicated BTF type info.
355
5f9ae91f 356config PAHOLE_HAS_SPLIT_BTF
6323c813 357 def_bool PAHOLE_VERSION >= 119
5f9ae91f 358
7472d5a6 359config PAHOLE_HAS_BTF_TAG
6323c813 360 def_bool PAHOLE_VERSION >= 123
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361 depends on CC_IS_CLANG
362 help
363 Decide whether pahole emits btf_tag attributes (btf_type_tag and
364 btf_decl_tag) or not. Currently only clang compiler implements
365 these attributes, so make the config depend on CC_IS_CLANG.
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366
367config DEBUG_INFO_BTF_MODULES
368 def_bool y
369 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
370 help
371 Generate compact split BTF type information for kernel modules.
372
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373config MODULE_ALLOW_BTF_MISMATCH
374 bool "Allow loading modules with non-matching BTF type info"
375 depends on DEBUG_INFO_BTF_MODULES
376 help
377 For modules whose split BTF does not match vmlinux, load without
378 BTF rather than refusing to load. The default behavior with
379 module BTF enabled is to reject modules with such mismatches;
380 this option will still load module BTF where possible but ignore
381 it when a mismatch is found.
382
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383config GDB_SCRIPTS
384 bool "Provide GDB scripts for kernel debugging"
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385 help
386 This creates the required links to GDB helper scripts in the
387 build directory. If you load vmlinux into gdb, the helper
388 scripts will be automatically imported by gdb as well, and
389 additional functions are available to analyze a Linux kernel
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390 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
391 for further details.
3ee7b3fa 392
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393endif # DEBUG_INFO
394
35bb5b1e 395config FRAME_WARN
a83e4ca2 396 int "Warn for stack frames larger than"
35bb5b1e 397 range 0 8192
ac66998d 398 default 0 if KMSAN
0e07f663 399 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
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400 default 2048 if PARISC
401 default 1536 if (!64BIT && XTENSA)
152fe65f 402 default 1280 if KASAN && !64BIT
8d192bec 403 default 1024 if !64BIT
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404 default 2048 if 64BIT
405 help
921757bc 406 Tell the compiler to warn at build time for stack frames larger than this.
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407 Setting this too low will cause a lot of warnings.
408 Setting it to 0 disables the warning.
35bb5b1e 409
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410config STRIP_ASM_SYMS
411 bool "Strip assembler-generated symbols during link"
412 default n
413 help
414 Strip internal assembler-generated symbols during a link (symbols
415 that look like '.Lxxx') so they don't pollute the output of
416 get_wchan() and suchlike.
417
1873e870 418config READABLE_ASM
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419 bool "Generate readable assembler code"
420 depends on DEBUG_KERNEL
7d73c3e9 421 depends on CC_IS_GCC
bf4735a4 422 help
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423 Disable some compiler optimizations that tend to generate human unreadable
424 assembler output. This may make the kernel slightly slower, but it helps
425 to keep kernel developers who have to stare a lot at assembler listings
426 sane.
bf4735a4 427
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428config HEADERS_INSTALL
429 bool "Install uapi headers to usr/include"
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430 depends on !UML
431 help
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432 This option will install uapi headers (headers exported to user-space)
433 into the usr/include directory for use during the kernel build.
434 This is unneeded for building the kernel itself, but needed for some
435 user-space program samples. It is also needed by some features such
436 as uapi header sanity checks.
437
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438config DEBUG_SECTION_MISMATCH
439 bool "Enable full Section mismatch analysis"
7d73c3e9 440 depends on CC_IS_GCC
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441 help
442 The section mismatch analysis checks if there are illegal
443 references from one section to another section.
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444 During linktime or runtime, some sections are dropped;
445 any use of code/data previously in these sections would
91341d4b 446 most likely result in an oops.
e809ab01 447 In the code, functions and variables are annotated with
0db0628d 448 __init,, etc. (see the full list in include/linux/init.h),
d6fbfa4f 449 which results in the code/data being placed in specific sections.
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450 The section mismatch analysis is always performed after a full
451 kernel build, and enabling this option causes the following
b7dca6dd 452 additional step to occur:
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453 - Add the option -fno-inline-functions-called-once to gcc commands.
454 When inlining a function annotated with __init in a non-init
455 function, we would lose the section information and thus
91341d4b 456 the analysis would not catch the illegal reference.
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457 This option tells gcc to inline less (but it does result in
458 a larger kernel).
91341d4b 459
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460config SECTION_MISMATCH_WARN_ONLY
461 bool "Make section mismatch errors non-fatal"
462 default y
463 help
464 If you say N here, the build process will fail if there are any
465 section mismatch, instead of just throwing warnings.
466
467 If unsure, say Y.
468
cf536e18 469config DEBUG_FORCE_FUNCTION_ALIGN_64B
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470 bool "Force all function address 64B aligned"
471 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
d49a0626 472 select FUNCTION_ALIGNMENT_64B
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473 help
474 There are cases that a commit from one domain changes the function
475 address alignment of other domains, and cause magic performance
476 bump (regression or improvement). Enable this option will help to
477 verify if the bump is caused by function alignment changes, while
478 it will slightly increase the kernel size and affect icache usage.
479
480 It is mainly for debug and performance tuning use.
481
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482#
483# Select this config option from the architecture Kconfig, if it
484# is preferred to always offer frame pointers as a config
485# option on the architecture (regardless of KERNEL_DEBUG):
486#
487config ARCH_WANT_FRAME_POINTERS
488 bool
f346f4b3 489
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490config FRAME_POINTER
491 bool "Compile the kernel with frame pointers"
a687a533 492 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
6dfc0665 493 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
a304e1b8 494 help
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495 If you say Y here the resulting kernel image will be slightly
496 larger and slower, but it gives very useful debugging information
497 in case of kernel bugs. (precise oopses/stacktraces/warnings)
a304e1b8 498
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499config OBJTOOL
500 bool
501
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502config STACK_VALIDATION
503 bool "Compile-time stack metadata validation"
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504 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
505 select OBJTOOL
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506 default n
507 help
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508 Validate frame pointer rules at compile-time. This helps ensure that
509 runtime stack traces are more reliable.
ee9f8fce 510
b9ab5ebb 511 For more information, see
d6a21f2d 512 tools/objtool/Documentation/objtool.txt.
b9ab5ebb 513
0f620cef 514config NOINSTR_VALIDATION
6804c1af 515 bool
489e355b 516 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
03f16cd0 517 select OBJTOOL
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518 default y
519
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520config VMLINUX_MAP
521 bool "Generate vmlinux.map file when linking"
522 depends on EXPERT
523 help
524 Selecting this option will pass "-Map=vmlinux.map" to ld
525 when linking vmlinux. That file can be useful for verifying
526 and debugging magic section games, and for seeing which
527 pieces of code get eliminated with
528 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
529
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530config DEBUG_FORCE_WEAK_PER_CPU
531 bool "Force weak per-cpu definitions"
532 depends on DEBUG_KERNEL
8446f1d3 533 help
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534 s390 and alpha require percpu variables in modules to be
535 defined weak to work around addressing range issue which
536 puts the following two restrictions on percpu variable
537 definitions.
8446f1d3 538
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539 1. percpu symbols must be unique whether static or not
540 2. percpu variables can't be defined inside a function
8446f1d3 541
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542 To ensure that generic code follows the above rules, this
543 option forces all percpu variables to be defined as weak.
5f329089 544
6dfc0665 545endmenu # "Compiler options"
8446f1d3 546
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547menu "Generic Kernel Debugging Instruments"
548
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549config MAGIC_SYSRQ
550 bool "Magic SysRq key"
551 depends on !UML
552 help
553 If you say Y here, you will have some control over the system even
554 if the system crashes for example during kernel debugging (e.g., you
555 will be able to flush the buffer cache to disk, reboot the system
556 immediately or dump some status information). This is accomplished
557 by pressing various keys while holding SysRq (Alt+PrintScreen). It
558 also works on a serial console (on PC hardware at least), if you
559 send a BREAK and then within 5 seconds a command keypress. The
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560 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
561 Don't say Y unless you really know what this hack does.
8446f1d3 562
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563config MAGIC_SYSRQ_DEFAULT_ENABLE
564 hex "Enable magic SysRq key functions by default"
565 depends on MAGIC_SYSRQ
566 default 0x1
567 help
568 Specifies which SysRq key functions are enabled by default.
569 This may be set to 1 or 0 to enable or disable them all, or
f8998c22 570 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
8eaede49 571
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572config MAGIC_SYSRQ_SERIAL
573 bool "Enable magic SysRq key over serial"
574 depends on MAGIC_SYSRQ
575 default y
576 help
577 Many embedded boards have a disconnected TTL level serial which can
578 generate some garbage that can lead to spurious false sysrq detects.
579 This option allows you to decide whether you want to enable the
580 magic SysRq key.
581
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582config MAGIC_SYSRQ_SERIAL_SEQUENCE
583 string "Char sequence that enables magic SysRq over serial"
584 depends on MAGIC_SYSRQ_SERIAL
585 default ""
586 help
587 Specifies a sequence of characters that can follow BREAK to enable
588 SysRq on a serial console.
589
d3394b3d
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590 If unsure, leave an empty string and the option will not be enabled.
591
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592config DEBUG_FS
593 bool "Debug Filesystem"
594 help
595 debugfs is a virtual file system that kernel developers use to put
596 debugging files into. Enable this option to be able to read and
597 write to these files.
598
599 For detailed documentation on the debugfs API, see
600 Documentation/filesystems/.
601
602 If unsure, say N.
603
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PE
604choice
605 prompt "Debugfs default access"
606 depends on DEBUG_FS
607 default DEBUG_FS_ALLOW_ALL
608 help
609 This selects the default access restrictions for debugfs.
610 It can be overridden with kernel command line option
611 debugfs=[on,no-mount,off]. The restrictions apply for API access
612 and filesystem registration.
613
614config DEBUG_FS_ALLOW_ALL
615 bool "Access normal"
616 help
617 No restrictions apply. Both API and filesystem registration
618 is on. This is the normal default operation.
619
620config DEBUG_FS_DISALLOW_MOUNT
621 bool "Do not register debugfs as filesystem"
622 help
623 The API is open but filesystem is not loaded. Clients can still do
624 their work and read with debug tools that do not need
625 debugfs filesystem.
626
627config DEBUG_FS_ALLOW_NONE
628 bool "No access"
629 help
630 Access is off. Clients get -PERM when trying to create nodes in
631 debugfs tree and debugfs is not registered as a filesystem.
632 Client can then back-off or continue without debugfs access.
633
634endchoice
635
6210b640 636source "lib/Kconfig.kgdb"
6210b640 637source "lib/Kconfig.ubsan"
2645d432 638source "lib/Kconfig.kcsan"
6210b640
CD
639
640endmenu
641
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642menu "Networking Debugging"
643
644source "net/Kconfig.debug"
645
646endmenu # "Networking Debugging"
c66d7a27 647
0610c8a8 648menu "Memory Debugging"
fef2c9bc 649
8636a1f9 650source "mm/Kconfig.debug"
fef2c9bc 651
0610c8a8
DH
652config DEBUG_OBJECTS
653 bool "Debug object operations"
654 depends on DEBUG_KERNEL
9c44bc03 655 help
0610c8a8
DH
656 If you say Y here, additional code will be inserted into the
657 kernel to track the life time of various objects and validate
658 the operations on those objects.
9c44bc03 659
0610c8a8
DH
660config DEBUG_OBJECTS_SELFTEST
661 bool "Debug objects selftest"
662 depends on DEBUG_OBJECTS
663 help
664 This enables the selftest of the object debug code.
9c44bc03 665
0610c8a8
DH
666config DEBUG_OBJECTS_FREE
667 bool "Debug objects in freed memory"
668 depends on DEBUG_OBJECTS
669 help
670 This enables checks whether a k/v free operation frees an area
671 which contains an object which has not been deactivated
672 properly. This can make kmalloc/kfree-intensive workloads
673 much slower.
3ac7fe5a 674
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TG
675config DEBUG_OBJECTS_TIMERS
676 bool "Debug timer objects"
677 depends on DEBUG_OBJECTS
678 help
679 If you say Y here, additional code will be inserted into the
680 timer routines to track the life time of timer objects and
681 validate the timer operations.
682
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TG
683config DEBUG_OBJECTS_WORK
684 bool "Debug work objects"
685 depends on DEBUG_OBJECTS
686 help
687 If you say Y here, additional code will be inserted into the
688 work queue routines to track the life time of work objects and
689 validate the work operations.
690
551d55a9
MD
691config DEBUG_OBJECTS_RCU_HEAD
692 bool "Debug RCU callbacks objects"
fc2ecf7e 693 depends on DEBUG_OBJECTS
551d55a9
MD
694 help
695 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
696
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TH
697config DEBUG_OBJECTS_PERCPU_COUNTER
698 bool "Debug percpu counter objects"
699 depends on DEBUG_OBJECTS
700 help
701 If you say Y here, additional code will be inserted into the
702 percpu counter routines to track the life time of percpu counter
703 objects and validate the percpu counter operations.
704
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705config DEBUG_OBJECTS_ENABLE_DEFAULT
706 int "debug_objects bootup default value (0-1)"
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KK
707 range 0 1
708 default "1"
709 depends on DEBUG_OBJECTS
710 help
711 Debug objects boot parameter default value
3ae70205 712
5035ebc6 713config SHRINKER_DEBUG
5035ebc6
RG
714 bool "Enable shrinker debugging support"
715 depends on DEBUG_FS
716 help
717 Say Y to enable the shrinker debugfs interface which provides
718 visibility into the kernel memory shrinkers subsystem.
719 Disable it to avoid an extra memory footprint.
720
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721config HAVE_DEBUG_KMEMLEAK
722 bool
723
3bba00d7
CM
724config DEBUG_KMEMLEAK
725 bool "Kernel memory leak detector"
525c1f92 726 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
79e0d9bd 727 select DEBUG_FS
3bba00d7
CM
728 select STACKTRACE if STACKTRACE_SUPPORT
729 select KALLSYMS
b60e26a2 730 select CRC32
3bba00d7
CM
731 help
732 Say Y here if you want to enable the memory leak
733 detector. The memory allocation/freeing is traced in a way
734 similar to the Boehm's conservative garbage collector, the
735 difference being that the orphan objects are not freed but
736 only shown in /sys/kernel/debug/kmemleak. Enabling this
737 feature will introduce an overhead to memory
700199b0 738 allocations. See Documentation/dev-tools/kmemleak.rst for more
3bba00d7
CM
739 details.
740
0610c8a8
DH
741 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
742 of finding leaks due to the slab objects poisoning.
743
744 In order to access the kmemleak file, debugfs needs to be
745 mounted (usually at /sys/kernel/debug).
746
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CM
747config DEBUG_KMEMLEAK_MEM_POOL_SIZE
748 int "Kmemleak memory pool size"
0610c8a8 749 depends on DEBUG_KMEMLEAK
c59180ae 750 range 200 1000000
b751c52b 751 default 16000
0610c8a8
DH
752 help
753 Kmemleak must track all the memory allocations to avoid
754 reporting false positives. Since memory may be allocated or
c5665868
CM
755 freed before kmemleak is fully initialised, use a static pool
756 of metadata objects to track such callbacks. After kmemleak is
757 fully initialised, this memory pool acts as an emergency one
758 if slab allocations fail.
0610c8a8
DH
759
760config DEBUG_KMEMLEAK_TEST
761 tristate "Simple test for the kernel memory leak detector"
762 depends on DEBUG_KMEMLEAK && m
763 help
764 This option enables a module that explicitly leaks memory.
765
766 If unsure, say N.
767
768config DEBUG_KMEMLEAK_DEFAULT_OFF
769 bool "Default kmemleak to off"
770 depends on DEBUG_KMEMLEAK
771 help
772 Say Y here to disable kmemleak by default. It can then be enabled
773 on the command line via kmemleak=on.
774
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SK
775config DEBUG_KMEMLEAK_AUTO_SCAN
776 bool "Enable kmemleak auto scan thread on boot up"
777 default y
778 depends on DEBUG_KMEMLEAK
779 help
780 Depending on the cpu, kmemleak scan may be cpu intensive and can
781 stall user tasks at times. This option enables/disables automatic
782 kmemleak scan at boot up.
783
784 Say N here to disable kmemleak auto scan thread to stop automatic
785 scanning. Disabling this option disables automatic reporting of
786 memory leaks.
787
788 If unsure, say Y.
789
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DH
790config DEBUG_STACK_USAGE
791 bool "Stack utilization instrumentation"
6c31da34 792 depends on DEBUG_KERNEL && !IA64
0610c8a8
DH
793 help
794 Enables the display of the minimum amount of free stack which each
795 task has ever had available in the sysrq-T and sysrq-P debug output.
796
797 This option will slow down process creation somewhat.
798
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799config SCHED_STACK_END_CHECK
800 bool "Detect stack corruption on calls to schedule()"
801 depends on DEBUG_KERNEL
802 default n
803 help
804 This option checks for a stack overrun on calls to schedule().
805 If the stack end location is found to be over written always panic as
806 the content of the corrupted region can no longer be trusted.
807 This is to ensure no erroneous behaviour occurs which could result in
808 data corruption or a sporadic crash at a later stage once the region
809 is examined. The runtime overhead introduced is minimal.
810
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811config ARCH_HAS_DEBUG_VM_PGTABLE
812 bool
813 help
814 An architecture should select this when it can successfully
815 build and run DEBUG_VM_PGTABLE.
816
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TG
817config DEBUG_VM_IRQSOFF
818 def_bool DEBUG_VM && !PREEMPT_RT
819
0610c8a8
DH
820config DEBUG_VM
821 bool "Debug VM"
822 depends on DEBUG_KERNEL
823 help
824 Enable this to turn on extended checks in the virtual-memory system
68d4b3df 825 that may impact performance.
0610c8a8
DH
826
827 If unsure, say N.
828
54a611b6
LH
829config DEBUG_VM_MAPLE_TREE
830 bool "Debug VM maple trees"
4f115147 831 depends on DEBUG_VM
54a611b6 832 select DEBUG_MAPLE_TREE
4f115147 833 help
54a611b6 834 Enable VM maple tree debugging information and extra validations.
4f115147
DB
835
836 If unsure, say N.
837
0610c8a8
DH
838config DEBUG_VM_RB
839 bool "Debug VM red-black trees"
840 depends on DEBUG_VM
841 help
a663dad6 842 Enable VM red-black tree debugging information and extra validations.
0610c8a8
DH
843
844 If unsure, say N.
845
95ad9755
KS
846config DEBUG_VM_PGFLAGS
847 bool "Debug page-flags operations"
848 depends on DEBUG_VM
849 help
850 Enables extra validation on page flags operations.
851
852 If unsure, say N.
853
399145f9
AK
854config DEBUG_VM_PGTABLE
855 bool "Debug arch page table for semantics compliance"
856 depends on MMU
857 depends on ARCH_HAS_DEBUG_VM_PGTABLE
858 default y if DEBUG_VM
859 help
860 This option provides a debug method which can be used to test
861 architecture page table helper functions on various platforms in
862 verifying if they comply with expected generic MM semantics. This
863 will help architecture code in making sure that any changes or
864 new additions of these helpers still conform to expected
865 semantics of the generic MM. Platforms will have to opt in for
866 this through ARCH_HAS_DEBUG_VM_PGTABLE.
867
868 If unsure, say N.
869
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LA
870config ARCH_HAS_DEBUG_VIRTUAL
871 bool
872
0610c8a8
DH
873config DEBUG_VIRTUAL
874 bool "Debug VM translations"
fa5b6ec9 875 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
0610c8a8
DH
876 help
877 Enable some costly sanity checks in virtual to page code. This can
878 catch mistakes with virt_to_page() and friends.
879
880 If unsure, say N.
881
882config DEBUG_NOMMU_REGIONS
883 bool "Debug the global anon/private NOMMU mapping region tree"
884 depends on DEBUG_KERNEL && !MMU
885 help
886 This option causes the global tree of anonymous and private mapping
887 regions to be regularly checked for invalid topology.
888
889config DEBUG_MEMORY_INIT
890 bool "Debug memory initialisation" if EXPERT
891 default !EXPERT
892 help
893 Enable this for additional checks during memory initialisation.
894 The sanity checks verify aspects of the VM such as the memory model
895 and other information provided by the architecture. Verbose
896 information will be printed at KERN_DEBUG loglevel depending
897 on the mminit_loglevel= command-line option.
898
899 If unsure, say Y
900
901config MEMORY_NOTIFIER_ERROR_INJECT
902 tristate "Memory hotplug notifier error injection module"
50f9481e 903 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
0610c8a8
DH
904 help
905 This option provides the ability to inject artificial errors to
906 memory hotplug notifier chain callbacks. It is controlled through
907 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
908
909 If the notifier call chain should be failed with some events
910 notified, write the error code to "actions/<notifier event>/error".
911
912 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
913
914 # cd /sys/kernel/debug/notifier-error-inject/memory
915 # echo -12 > actions/MEM_GOING_OFFLINE/error
916 # echo offline > /sys/devices/system/memory/memoryXXX/state
917 bash: echo: write error: Cannot allocate memory
918
919 To compile this code as a module, choose M here: the module will
920 be called memory-notifier-error-inject.
921
922 If unsure, say N.
923
924config DEBUG_PER_CPU_MAPS
925 bool "Debug access to per_cpu maps"
926 depends on DEBUG_KERNEL
927 depends on SMP
928 help
929 Say Y to verify that the per_cpu map being accessed has
930 been set up. This adds a fair amount of code to kernel memory
931 and decreases performance.
932
933 Say N if unsure.
934
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TG
935config DEBUG_KMAP_LOCAL
936 bool "Debug kmap_local temporary mappings"
937 depends on DEBUG_KERNEL && KMAP_LOCAL
938 help
939 This option enables additional error checking for the kmap_local
940 infrastructure. Disable for production use.
941
0e91a0c6
TG
942config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
943 bool
944
945config DEBUG_KMAP_LOCAL_FORCE_MAP
946 bool "Enforce kmap_local temporary mappings"
947 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
948 select KMAP_LOCAL
949 select DEBUG_KMAP_LOCAL
950 help
951 This option enforces temporary mappings through the kmap_local
952 mechanism for non-highmem pages and on non-highmem systems.
953 Disable this for production systems!
954
0610c8a8
DH
955config DEBUG_HIGHMEM
956 bool "Highmem debugging"
957 depends on DEBUG_KERNEL && HIGHMEM
0e91a0c6 958 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
6e799cb6 959 select DEBUG_KMAP_LOCAL
0610c8a8 960 help
b1357c9f
GU
961 This option enables additional error checking for high memory
962 systems. Disable for production systems.
0610c8a8
DH
963
964config HAVE_DEBUG_STACKOVERFLOW
965 bool
966
967config DEBUG_STACKOVERFLOW
968 bool "Check for stack overflows"
969 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
a7f7f624 970 help
0610c8a8 971 Say Y here if you want to check for overflows of kernel, IRQ
edb0ec07 972 and exception stacks (if your architecture uses them). This
0610c8a8
DH
973 option will show detailed messages if free stack space drops
974 below a certain limit.
975
976 These kinds of bugs usually occur when call-chains in the
977 kernel get too deep, especially when interrupts are
978 involved.
979
980 Use this in cases where you see apparently random memory
981 corruption, especially if it appears in 'struct thread_info'
982
983 If in doubt, say "N".
984
0b24becc 985source "lib/Kconfig.kasan"
0ce20dd8 986source "lib/Kconfig.kfence"
f80be457 987source "lib/Kconfig.kmsan"
0b24becc 988
0610c8a8
DH
989endmenu # "Memory Debugging"
990
a304e1b8
DW
991config DEBUG_SHIRQ
992 bool "Debug shared IRQ handlers"
0244ad00 993 depends on DEBUG_KERNEL
a304e1b8 994 help
0a2fae2a
WS
995 Enable this to generate a spurious interrupt just before a shared
996 interrupt handler is deregistered (generating one when registering
997 is currently disabled). Drivers need to handle this correctly. Some
998 don't and need to be caught.
a304e1b8 999
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CD
1000menu "Debug Oops, Lockups and Hangs"
1001
1002config PANIC_ON_OOPS
1003 bool "Panic on Oops"
1004 help
1005 Say Y here to enable the kernel to panic when it oopses. This
1006 has the same effect as setting oops=panic on the kernel command
1007 line.
1008
1009 This feature is useful to ensure that the kernel does not do
1010 anything erroneous after an oops which could result in data
1011 corruption or other issues.
1012
1013 Say N if unsure.
1014
1015config PANIC_ON_OOPS_VALUE
1016 int
1017 range 0 1
1018 default 0 if !PANIC_ON_OOPS
1019 default 1 if PANIC_ON_OOPS
1020
1021config PANIC_TIMEOUT
1022 int "panic timeout"
1023 default 0
1024 help
9d5b134f 1025 Set the timeout value (in seconds) until a reboot occurs when
f43a289d
CD
1026 the kernel panics. If n = 0, then we wait forever. A timeout
1027 value n > 0 will wait n seconds before rebooting, while a timeout
1028 value n < 0 will reboot immediately.
92aef8fb 1029
58687acb 1030config LOCKUP_DETECTOR
05a4a952
NP
1031 bool
1032
1033config SOFTLOCKUP_DETECTOR
1034 bool "Detect Soft Lockups"
dea20a3f 1035 depends on DEBUG_KERNEL && !S390
05a4a952 1036 select LOCKUP_DETECTOR
8446f1d3 1037 help
58687acb 1038 Say Y here to enable the kernel to act as a watchdog to detect
05a4a952 1039 soft lockups.
58687acb
DZ
1040
1041 Softlockups are bugs that cause the kernel to loop in kernel
5f329089 1042 mode for more than 20 seconds, without giving other tasks a
58687acb
DZ
1043 chance to run. The current stack trace is displayed upon
1044 detection and the system will stay locked up.
8446f1d3 1045
5f00ae0d
RD
1046config BOOTPARAM_SOFTLOCKUP_PANIC
1047 bool "Panic (Reboot) On Soft Lockups"
1048 depends on SOFTLOCKUP_DETECTOR
1049 help
1050 Say Y here to enable the kernel to panic on "soft lockups",
1051 which are bugs that cause the kernel to loop in kernel
1052 mode for more than 20 seconds (configurable using the watchdog_thresh
1053 sysctl), without giving other tasks a chance to run.
1054
1055 The panic can be used in combination with panic_timeout,
1056 to cause the system to reboot automatically after a
1057 lockup has been detected. This feature is useful for
1058 high-availability systems that have uptime guarantees and
1059 where a lockup must be resolved ASAP.
1060
1061 Say N if unsure.
1062
05a4a952
NP
1063config HARDLOCKUP_DETECTOR_PERF
1064 bool
1065 select SOFTLOCKUP_DETECTOR
1066
7edaeb68
TG
1067#
1068# Enables a timestamp based low pass filter to compensate for perf based
1069# hard lockup detection which runs too fast due to turbo modes.
1070#
1071config HARDLOCKUP_CHECK_TIMESTAMP
1072 bool
1073
05a4a952
NP
1074#
1075# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1076# lockup detector rather than the perf based detector.
1077#
1078config HARDLOCKUP_DETECTOR
1079 bool "Detect Hard Lockups"
1080 depends on DEBUG_KERNEL && !S390
1081 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1082 select LOCKUP_DETECTOR
1083 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
05a4a952
NP
1084 help
1085 Say Y here to enable the kernel to act as a watchdog to detect
1086 hard lockups.
1087
58687acb 1088 Hardlockups are bugs that cause the CPU to loop in kernel mode
5f329089 1089 for more than 10 seconds, without letting other interrupts have a
58687acb
DZ
1090 chance to run. The current stack trace is displayed upon detection
1091 and the system will stay locked up.
8446f1d3 1092
fef2c9bc
DZ
1093config BOOTPARAM_HARDLOCKUP_PANIC
1094 bool "Panic (Reboot) On Hard Lockups"
8f1f66ed 1095 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
1096 help
1097 Say Y here to enable the kernel to panic on "hard lockups",
1098 which are bugs that cause the kernel to loop in kernel
5f329089
FLVC
1099 mode with interrupts disabled for more than 10 seconds (configurable
1100 using the watchdog_thresh sysctl).
fef2c9bc
DZ
1101
1102 Say N if unsure.
1103
e162b39a
MSB
1104config DETECT_HUNG_TASK
1105 bool "Detect Hung Tasks"
1106 depends on DEBUG_KERNEL
05a4a952 1107 default SOFTLOCKUP_DETECTOR
e162b39a 1108 help
0610c8a8
DH
1109 Say Y here to enable the kernel to detect "hung tasks",
1110 which are bugs that cause the task to be stuck in
96b03ab8 1111 uninterruptible "D" state indefinitely.
1da177e4 1112
0610c8a8
DH
1113 When a hung task is detected, the kernel will print the
1114 current stack trace (which you should report), but the
1115 task will stay in uninterruptible state. If lockdep is
1116 enabled then all held locks will also be reported. This
1117 feature has negligible overhead.
871751e2 1118
0610c8a8
DH
1119config DEFAULT_HUNG_TASK_TIMEOUT
1120 int "Default timeout for hung task detection (in seconds)"
1121 depends on DETECT_HUNG_TASK
1122 default 120
f0630fff 1123 help
0610c8a8
DH
1124 This option controls the default timeout (in seconds) used
1125 to determine when a task has become non-responsive and should
1126 be considered hung.
f0630fff 1127
0610c8a8
DH
1128 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1129 sysctl or by writing a value to
1130 /proc/sys/kernel/hung_task_timeout_secs.
8ff12cfc 1131
0610c8a8
DH
1132 A timeout of 0 disables the check. The default is two minutes.
1133 Keeping the default should be fine in most cases.
b69ec42b 1134
0610c8a8
DH
1135config BOOTPARAM_HUNG_TASK_PANIC
1136 bool "Panic (Reboot) On Hung Tasks"
1137 depends on DETECT_HUNG_TASK
3bba00d7 1138 help
0610c8a8
DH
1139 Say Y here to enable the kernel to panic on "hung tasks",
1140 which are bugs that cause the kernel to leave a task stuck
1141 in uninterruptible "D" state.
3bba00d7 1142
0610c8a8
DH
1143 The panic can be used in combination with panic_timeout,
1144 to cause the system to reboot automatically after a
1145 hung task has been detected. This feature is useful for
1146 high-availability systems that have uptime guarantees and
1147 where a hung tasks must be resolved ASAP.
bf96d1e3 1148
0610c8a8 1149 Say N if unsure.
bf96d1e3 1150
82607adc
TH
1151config WQ_WATCHDOG
1152 bool "Detect Workqueue Stalls"
1153 depends on DEBUG_KERNEL
1154 help
1155 Say Y here to enable stall detection on workqueues. If a
1156 worker pool doesn't make forward progress on a pending work
1157 item for over a given amount of time, 30s by default, a
1158 warning message is printed along with dump of workqueue
1159 state. This can be configured through kernel parameter
1160 "workqueue.watchdog_thresh" and its sysfs counterpart.
1161
30428ef5
KK
1162config TEST_LOCKUP
1163 tristate "Test module to generate lockups"
63646bc9 1164 depends on m
30428ef5
KK
1165 help
1166 This builds the "test_lockup" module that helps to make sure
1167 that watchdogs and lockup detectors are working properly.
1168
1169 Depending on module parameters it could emulate soft or hard
1170 lockup, "hung task", or locking arbitrary lock for a long time.
1171 Also it could generate series of lockups with cooling-down periods.
1172
1173 If unsure, say N.
1174
92aef8fb
DH
1175endmenu # "Debug lockups and hangs"
1176
ebebdd09 1177menu "Scheduler Debugging"
5800dc3c 1178
0610c8a8
DH
1179config SCHED_DEBUG
1180 bool "Collect scheduler debugging info"
1181 depends on DEBUG_KERNEL && PROC_FS
1182 default y
0822ee4a 1183 help
0610c8a8
DH
1184 If you say Y here, the /proc/sched_debug file will be provided
1185 that can help debug the scheduler. The runtime overhead of this
1186 option is minimal.
0822ee4a 1187
f6db8347
NR
1188config SCHED_INFO
1189 bool
1190 default n
1191
0610c8a8
DH
1192config SCHEDSTATS
1193 bool "Collect scheduler statistics"
1194 depends on DEBUG_KERNEL && PROC_FS
f6db8347 1195 select SCHED_INFO
0610c8a8
DH
1196 help
1197 If you say Y here, additional code will be inserted into the
1198 scheduler and related routines to collect statistics about
1199 scheduler behavior and provide them in /proc/schedstat. These
1200 stats may be useful for both tuning and debugging the scheduler
1201 If you aren't debugging the scheduler or trying to tune a specific
1202 application, you can say N to avoid the very slight overhead
1203 this adds.
0822ee4a 1204
ebebdd09 1205endmenu
0d9e2632 1206
3c17ad19
JS
1207config DEBUG_TIMEKEEPING
1208 bool "Enable extra timekeeping sanity checking"
1209 help
1210 This option will enable additional timekeeping sanity checks
1211 which may be helpful when diagnosing issues where timekeeping
1212 problems are suspected.
1213
1214 This may include checks in the timekeeping hotpaths, so this
1215 option may have a (very small) performance impact to some
1216 workloads.
1217
1218 If unsure, say N.
1219
1da177e4
LT
1220config DEBUG_PREEMPT
1221 bool "Debug preemptible kernel"
9f472869 1222 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1da177e4
LT
1223 default y
1224 help
1225 If you say Y here then the kernel will use a debug variant of the
1226 commonly used smp_processor_id() function and will print warnings
1227 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1228 will detect preemption count underflows.
1229
9eade16b
DH
1230menu "Lock Debugging (spinlocks, mutexes, etc...)"
1231
f07cbebb
WL
1232config LOCK_DEBUGGING_SUPPORT
1233 bool
1234 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1235 default y
1236
19193bca
WL
1237config PROVE_LOCKING
1238 bool "Lock debugging: prove locking correctness"
1239 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1240 select LOCKDEP
1241 select DEBUG_SPINLOCK
bb630f9f 1242 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca 1243 select DEBUG_RT_MUTEXES if RT_MUTEXES
c71fd893 1244 select DEBUG_RWSEMS
19193bca
WL
1245 select DEBUG_WW_MUTEX_SLOWPATH
1246 select DEBUG_LOCK_ALLOC
8fd8ad5c 1247 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
19193bca
WL
1248 select TRACE_IRQFLAGS
1249 default n
1250 help
1251 This feature enables the kernel to prove that all locking
1252 that occurs in the kernel runtime is mathematically
1253 correct: that under no circumstance could an arbitrary (and
1254 not yet triggered) combination of observed locking
1255 sequences (on an arbitrary number of CPUs, running an
1256 arbitrary number of tasks and interrupt contexts) cause a
1257 deadlock.
1258
1259 In short, this feature enables the kernel to report locking
1260 related deadlocks before they actually occur.
1261
1262 The proof does not depend on how hard and complex a
1263 deadlock scenario would be to trigger: how many
1264 participant CPUs, tasks and irq-contexts would be needed
1265 for it to trigger. The proof also does not depend on
1266 timing: if a race and a resulting deadlock is possible
1267 theoretically (no matter how unlikely the race scenario
1268 is), it will be proven so and will immediately be
1269 reported by the kernel (once the event is observed that
1270 makes the deadlock theoretically possible).
1271
1272 If a deadlock is impossible (i.e. the locking rules, as
1273 observed by the kernel, are mathematically correct), the
1274 kernel reports nothing.
1275
1276 NOTE: this feature can also be enabled for rwlocks, mutexes
1277 and rwsems - in which case all dependencies between these
1278 different locking variants are observed and mapped too, and
1279 the proof of observed correctness is also maintained for an
1280 arbitrary combination of these separate locking variants.
1281
387b1468 1282 For more details, see Documentation/locking/lockdep-design.rst.
19193bca 1283
de8f5e4f
PZ
1284config PROVE_RAW_LOCK_NESTING
1285 bool "Enable raw_spinlock - spinlock nesting checks"
1286 depends on PROVE_LOCKING
1287 default n
1288 help
1289 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1290 that the lock nesting rules for PREEMPT_RT enabled kernels are
1291 not violated.
1292
1293 NOTE: There are known nesting problems. So if you enable this
1294 option expect lockdep splats until these problems have been fully
1295 addressed which is work in progress. This config switch allows to
1296 identify and analyze these problems. It will be removed and the
9dbbc3b9 1297 check permanently enabled once the main issues have been fixed.
de8f5e4f
PZ
1298
1299 If unsure, select N.
1300
19193bca
WL
1301config LOCK_STAT
1302 bool "Lock usage statistics"
1303 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1304 select LOCKDEP
1305 select DEBUG_SPINLOCK
bb630f9f 1306 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca
WL
1307 select DEBUG_RT_MUTEXES if RT_MUTEXES
1308 select DEBUG_LOCK_ALLOC
1309 default n
1310 help
1311 This feature enables tracking lock contention points
1312
387b1468 1313 For more details, see Documentation/locking/lockstat.rst
19193bca
WL
1314
1315 This also enables lock events required by "perf lock",
1316 subcommand of perf.
1317 If you want to use "perf lock", you also need to turn on
1318 CONFIG_EVENT_TRACING.
1319
1320 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1321 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1322
e7eebaf6
IM
1323config DEBUG_RT_MUTEXES
1324 bool "RT Mutex debugging, deadlock detection"
e7eebaf6
IM
1325 depends on DEBUG_KERNEL && RT_MUTEXES
1326 help
1327 This allows rt mutex semantics violations and rt mutex related
1328 deadlocks (lockups) to be detected and reported automatically.
1329
1da177e4 1330config DEBUG_SPINLOCK
4d9f34ad 1331 bool "Spinlock and rw-lock debugging: basic checks"
1da177e4 1332 depends on DEBUG_KERNEL
e335e3eb 1333 select UNINLINE_SPIN_UNLOCK
1da177e4
LT
1334 help
1335 Say Y here and build SMP to catch missing spinlock initialization
1336 and certain other kinds of spinlock errors commonly made. This is
1337 best used in conjunction with the NMI watchdog so that spinlock
1338 deadlocks are also debuggable.
1339
4d9f34ad
IM
1340config DEBUG_MUTEXES
1341 bool "Mutex debugging: basic checks"
bb630f9f 1342 depends on DEBUG_KERNEL && !PREEMPT_RT
4d9f34ad
IM
1343 help
1344 This feature allows mutex semantics violations to be detected and
1345 reported.
1346
23010027
DV
1347config DEBUG_WW_MUTEX_SLOWPATH
1348 bool "Wait/wound mutex debugging: Slowpath testing"
f07cbebb 1349 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
23010027
DV
1350 select DEBUG_LOCK_ALLOC
1351 select DEBUG_SPINLOCK
bb630f9f
TG
1352 select DEBUG_MUTEXES if !PREEMPT_RT
1353 select DEBUG_RT_MUTEXES if PREEMPT_RT
23010027
DV
1354 help
1355 This feature enables slowpath testing for w/w mutex users by
1356 injecting additional -EDEADLK wound/backoff cases. Together with
1357 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1358 will test all possible w/w mutex interface abuse with the
1359 exception of simply not acquiring all the required locks.
4d692373
RC
1360 Note that this feature can introduce significant overhead, so
1361 it really should not be enabled in a production or distro kernel,
1362 even a debug kernel. If you are a driver writer, enable it. If
1363 you are a distro, do not.
23010027 1364
5149cbac
WL
1365config DEBUG_RWSEMS
1366 bool "RW Semaphore debugging: basic checks"
c71fd893 1367 depends on DEBUG_KERNEL
5149cbac 1368 help
c71fd893
WL
1369 This debugging feature allows mismatched rw semaphore locks
1370 and unlocks to be detected and reported.
5149cbac 1371
4d9f34ad
IM
1372config DEBUG_LOCK_ALLOC
1373 bool "Lock debugging: detect incorrect freeing of live locks"
f07cbebb 1374 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1375 select DEBUG_SPINLOCK
bb630f9f 1376 select DEBUG_MUTEXES if !PREEMPT_RT
f5694788 1377 select DEBUG_RT_MUTEXES if RT_MUTEXES
4d9f34ad
IM
1378 select LOCKDEP
1379 help
1380 This feature will check whether any held lock (spinlock, rwlock,
1381 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1382 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1383 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1384 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1385 held during task exit.
1386
4d9f34ad
IM
1387config LOCKDEP
1388 bool
f07cbebb 1389 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1390 select STACKTRACE
4d9f34ad
IM
1391 select KALLSYMS
1392 select KALLSYMS_ALL
1393
395102db
DJ
1394config LOCKDEP_SMALL
1395 bool
1396
5dc33592
TH
1397config LOCKDEP_BITS
1398 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1399 depends on LOCKDEP && !LOCKDEP_SMALL
1400 range 10 30
1401 default 15
1402 help
1403 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1404
1405config LOCKDEP_CHAINS_BITS
1406 int "Bitsize for MAX_LOCKDEP_CHAINS"
1407 depends on LOCKDEP && !LOCKDEP_SMALL
1408 range 10 30
1409 default 16
1410 help
1411 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1412
1413config LOCKDEP_STACK_TRACE_BITS
1414 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1415 depends on LOCKDEP && !LOCKDEP_SMALL
1416 range 10 30
1417 default 19
1418 help
1419 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1420
1421config LOCKDEP_STACK_TRACE_HASH_BITS
1422 int "Bitsize for STACK_TRACE_HASH_SIZE"
1423 depends on LOCKDEP && !LOCKDEP_SMALL
1424 range 10 30
1425 default 14
1426 help
1427 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1428
1429config LOCKDEP_CIRCULAR_QUEUE_BITS
1430 int "Bitsize for elements in circular_queue struct"
1431 depends on LOCKDEP
1432 range 10 30
1433 default 12
1434 help
1435 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1436
4d9f34ad
IM
1437config DEBUG_LOCKDEP
1438 bool "Lock dependency engine debugging"
517e7aa5 1439 depends on DEBUG_KERNEL && LOCKDEP
997acaf6 1440 select DEBUG_IRQFLAGS
4d9f34ad
IM
1441 help
1442 If you say Y here, the lock dependency engine will do
1443 additional runtime checks to debug itself, at the price
1444 of more runtime overhead.
1445
d902db1e
FW
1446config DEBUG_ATOMIC_SLEEP
1447 bool "Sleep inside atomic section checking"
e8f7c70f 1448 select PREEMPT_COUNT
1da177e4 1449 depends on DEBUG_KERNEL
87a4c375 1450 depends on !ARCH_NO_PREEMPT
1da177e4
LT
1451 help
1452 If you say Y here, various routines which may sleep will become very
d902db1e
FW
1453 noisy if they are called inside atomic sections: when a spinlock is
1454 held, inside an rcu read side critical section, inside preempt disabled
1455 sections, inside an interrupt, etc...
1da177e4 1456
cae2ed9a
IM
1457config DEBUG_LOCKING_API_SELFTESTS
1458 bool "Locking API boot-time self-tests"
1459 depends on DEBUG_KERNEL
1460 help
1461 Say Y here if you want the kernel to run a short self-test during
1462 bootup. The self-test checks whether common types of locking bugs
1463 are detected by debugging mechanisms or not. (if you disable
9dbbc3b9 1464 lock debugging then those bugs won't be detected of course.)
cae2ed9a
IM
1465 The following locking APIs are covered: spinlocks, rwlocks,
1466 mutexes and rwsems.
1467
0af3fe1e
PM
1468config LOCK_TORTURE_TEST
1469 tristate "torture tests for locking"
1470 depends on DEBUG_KERNEL
1471 select TORTURE_TEST
0af3fe1e
PM
1472 help
1473 This option provides a kernel module that runs torture tests
1474 on kernel locking primitives. The kernel module may be built
1475 after the fact on the running kernel to be tested, if desired.
1476
1477 Say Y here if you want kernel locking-primitive torture tests
1478 to be built into the kernel.
1479 Say M if you want these torture tests to build as a module.
1480 Say N if you are unsure.
1481
f2a5fec1
CW
1482config WW_MUTEX_SELFTEST
1483 tristate "Wait/wound mutex selftests"
1484 help
1485 This option provides a kernel module that runs tests on the
1486 on the struct ww_mutex locking API.
1487
1488 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1489 with this test harness.
1490
1491 Say M if you want these self tests to build as a module.
1492 Say N if you are unsure.
1493
e9d338a0
PM
1494config SCF_TORTURE_TEST
1495 tristate "torture tests for smp_call_function*()"
1496 depends on DEBUG_KERNEL
1497 select TORTURE_TEST
1498 help
1499 This option provides a kernel module that runs torture tests
1500 on the smp_call_function() family of primitives. The kernel
1501 module may be built after the fact on the running kernel to
1502 be tested, if desired.
1503
35feb604
PM
1504config CSD_LOCK_WAIT_DEBUG
1505 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1506 depends on DEBUG_KERNEL
1507 depends on 64BIT
1508 default n
1509 help
1510 This option enables debug prints when CPUs are slow to respond
1511 to the smp_call_function*() IPI wrappers. These debug prints
1512 include the IPI handler function currently executing (if any)
1513 and relevant stack traces.
1514
9eade16b 1515endmenu # lock debugging
8637c099 1516
9eade16b 1517config TRACE_IRQFLAGS
ed004953 1518 depends on TRACE_IRQFLAGS_SUPPORT
9eade16b 1519 bool
5ca43f6c 1520 help
9eade16b
DH
1521 Enables hooks to interrupt enabling and disabling for
1522 either tracing or lock debugging.
5ca43f6c 1523
ed004953 1524config TRACE_IRQFLAGS_NMI
1525 def_bool y
1526 depends on TRACE_IRQFLAGS
1527 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1528
997acaf6
MR
1529config DEBUG_IRQFLAGS
1530 bool "Debug IRQ flag manipulation"
1531 help
1532 Enables checks for potentially unsafe enabling or disabling of
1533 interrupts, such as calling raw_local_irq_restore() when interrupts
1534 are enabled.
1535
8637c099 1536config STACKTRACE
0c38e1fe 1537 bool "Stack backtrace support"
8637c099 1538 depends on STACKTRACE_SUPPORT
0c38e1fe
DJ
1539 help
1540 This option causes the kernel to create a /proc/pid/stack for
1541 every process, showing its current stack trace.
1542 It is also used by various kernel debugging features that require
1543 stack trace generation.
5ca43f6c 1544
eecabf56
TT
1545config WARN_ALL_UNSEEDED_RANDOM
1546 bool "Warn for all uses of unseeded randomness"
1547 default n
d06bfd19
JD
1548 help
1549 Some parts of the kernel contain bugs relating to their use of
1550 cryptographically secure random numbers before it's actually possible
1551 to generate those numbers securely. This setting ensures that these
1552 flaws don't go unnoticed, by enabling a message, should this ever
1553 occur. This will allow people with obscure setups to know when things
1554 are going wrong, so that they might contact developers about fixing
1555 it.
1556
eecabf56
TT
1557 Unfortunately, on some models of some architectures getting
1558 a fully seeded CRNG is extremely difficult, and so this can
1559 result in dmesg getting spammed for a surprisingly long
1560 time. This is really bad from a security perspective, and
1561 so architecture maintainers really need to do what they can
1562 to get the CRNG seeded sooner after the system is booted.
4c5d114e 1563 However, since users cannot do anything actionable to
cc1e127b 1564 address this, by default this option is disabled.
eecabf56
TT
1565
1566 Say Y here if you want to receive warnings for all uses of
1567 unseeded randomness. This will be of use primarily for
4c5d114e 1568 those developers interested in improving the security of
eecabf56
TT
1569 Linux kernels running on their architecture (or
1570 subarchitecture).
d06bfd19 1571
1da177e4
LT
1572config DEBUG_KOBJECT
1573 bool "kobject debugging"
1574 depends on DEBUG_KERNEL
1575 help
1576 If you say Y here, some extra kobject debugging messages will be sent
aca52c39 1577 to the syslog.
1da177e4 1578
c817a67e
RK
1579config DEBUG_KOBJECT_RELEASE
1580 bool "kobject release debugging"
2a999aa0 1581 depends on DEBUG_OBJECTS_TIMERS
c817a67e
RK
1582 help
1583 kobjects are reference counted objects. This means that their
1584 last reference count put is not predictable, and the kobject can
b6c69474 1585 live on past the point at which a driver decides to drop its
c817a67e
RK
1586 initial reference to the kobject gained on allocation. An
1587 example of this would be a struct device which has just been
1588 unregistered.
1589
1590 However, some buggy drivers assume that after such an operation,
1591 the memory backing the kobject can be immediately freed. This
1592 goes completely against the principles of a refcounted object.
1593
1594 If you say Y here, the kernel will delay the release of kobjects
1595 on the last reference count to improve the visibility of this
1596 kind of kobject release bug.
1597
9b2a60c4
CM
1598config HAVE_DEBUG_BUGVERBOSE
1599 bool
1600
3be5cbcd 1601menu "Debug kernel data structures"
1da177e4 1602
199a9afc
DJ
1603config DEBUG_LIST
1604 bool "Debug linked list manipulation"
4520bcb2 1605 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
199a9afc
DJ
1606 help
1607 Enable this to turn on extended checks in the linked-list
1608 walking routines.
1609
1610 If unsure, say N.
1611
8e18faea 1612config DEBUG_PLIST
b8cfff68
DS
1613 bool "Debug priority linked list manipulation"
1614 depends on DEBUG_KERNEL
1615 help
1616 Enable this to turn on extended checks in the priority-ordered
1617 linked-list (plist) walking routines. This checks the entire
1618 list multiple times during each manipulation.
1619
1620 If unsure, say N.
1621
d6ec0842
JA
1622config DEBUG_SG
1623 bool "Debug SG table operations"
1624 depends on DEBUG_KERNEL
1625 help
1626 Enable this to turn on checks on scatter-gather tables. This can
1627 help find problems with drivers that do not properly initialize
1628 their sg tables.
1629
1630 If unsure, say N.
1631
1b2439db
AV
1632config DEBUG_NOTIFIERS
1633 bool "Debug notifier call chains"
1634 depends on DEBUG_KERNEL
1635 help
1636 Enable this to turn on sanity checking for notifier call chains.
1637 This is most useful for kernel developers to make sure that
1638 modules properly unregister themselves from notifier chains.
1639 This is a relatively cheap check but if you care about maximum
1640 performance, say N.
1641
3be5cbcd
CD
1642config BUG_ON_DATA_CORRUPTION
1643 bool "Trigger a BUG when data corruption is detected"
1644 select DEBUG_LIST
1645 help
1646 Select this option if the kernel should BUG when it encounters
1647 data corruption in kernel memory structures when they get checked
1648 for validity.
1649
1650 If unsure, say N.
1651
54a611b6
LH
1652config DEBUG_MAPLE_TREE
1653 bool "Debug maple trees"
1654 depends on DEBUG_KERNEL
1655 help
1656 Enable maple tree debugging information and extra validations.
1657
1658 If unsure, say N.
1659
3be5cbcd
CD
1660endmenu
1661
e0e81739
DH
1662config DEBUG_CREDENTIALS
1663 bool "Debug credential management"
1664 depends on DEBUG_KERNEL
1665 help
1666 Enable this to turn on some debug checking for credential
1667 management. The additional code keeps track of the number of
1668 pointers from task_structs to any given cred struct, and checks to
1669 see that this number never exceeds the usage count of the cred
1670 struct.
1671
1672 Furthermore, if SELinux is enabled, this also checks that the
1673 security pointer in the cred struct is never seen to be invalid.
1674
1675 If unsure, say N.
1676
43a0a2a7 1677source "kernel/rcu/Kconfig.debug"
2f03e3ca 1678
f303fccb
TH
1679config DEBUG_WQ_FORCE_RR_CPU
1680 bool "Force round-robin CPU selection for unbound work items"
1681 depends on DEBUG_KERNEL
1682 default n
1683 help
1684 Workqueue used to implicitly guarantee that work items queued
1685 without explicit CPU specified are put on the local CPU. This
1686 guarantee is no longer true and while local CPU is still
1687 preferred work items may be put on foreign CPUs. Kernel
1688 parameter "workqueue.debug_force_rr_cpu" is added to force
1689 round-robin CPU selection to flush out usages which depend on the
1690 now broken guarantee. This config option enables the debug
1691 feature by default. When enabled, memory and cache locality will
1692 be impacted.
1693
757c989b
TG
1694config CPU_HOTPLUG_STATE_CONTROL
1695 bool "Enable CPU hotplug state control"
1696 depends on DEBUG_KERNEL
1697 depends on HOTPLUG_CPU
1698 default n
1699 help
1700 Allows to write steps between "offline" and "online" to the CPUs
1701 sysfs target file so states can be stepped granular. This is a debug
1702 option for now as the hotplug machinery cannot be stopped and
1703 restarted at arbitrary points yet.
1704
1705 Say N if your are unsure.
1706
09a74952
CD
1707config LATENCYTOP
1708 bool "Latency measuring infrastructure"
1709 depends on DEBUG_KERNEL
1710 depends on STACKTRACE_SUPPORT
1711 depends on PROC_FS
7d37cb2c 1712 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
09a74952
CD
1713 select KALLSYMS
1714 select KALLSYMS_ALL
1715 select STACKTRACE
1716 select SCHEDSTATS
09a74952
CD
1717 help
1718 Enable this option if you want to use the LatencyTOP tool
1719 to find out which userspace is blocking on what kernel operations.
1720
6ab42860
TH
1721config DEBUG_CGROUP_REF
1722 bool "Disable inlining of cgroup css reference count functions"
1723 depends on DEBUG_KERNEL
1724 depends on CGROUPS
1725 depends on KPROBES
1726 default n
1727 help
1728 Force cgroup css reference count functions to not be inlined so
1729 that they can be kprobed for debugging.
1730
09a74952
CD
1731source "kernel/trace/Kconfig"
1732
1733config PROVIDE_OHCI1394_DMA_INIT
1734 bool "Remote debugging over FireWire early on boot"
1735 depends on PCI && X86
1736 help
1737 If you want to debug problems which hang or crash the kernel early
1738 on boot and the crashing machine has a FireWire port, you can use
1739 this feature to remotely access the memory of the crashed machine
1740 over FireWire. This employs remote DMA as part of the OHCI1394
1741 specification which is now the standard for FireWire controllers.
1742
1743 With remote DMA, you can monitor the printk buffer remotely using
1744 firescope and access all memory below 4GB using fireproxy from gdb.
1745 Even controlling a kernel debugger is possible using remote DMA.
1746
1747 Usage:
1748
1749 If ohci1394_dma=early is used as boot parameter, it will initialize
1750 all OHCI1394 controllers which are found in the PCI config space.
1751
1752 As all changes to the FireWire bus such as enabling and disabling
1753 devices cause a bus reset and thereby disable remote DMA for all
1754 devices, be sure to have the cable plugged and FireWire enabled on
1755 the debugging host before booting the debug target for debugging.
1756
1757 This code (~1k) is freed after boot. By then, the firewire stack
1758 in charge of the OHCI-1394 controllers should be used instead.
1759
a74e2a22 1760 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
09a74952 1761
045f6d79
CD
1762source "samples/Kconfig"
1763
1764config ARCH_HAS_DEVMEM_IS_ALLOWED
1765 bool
1766
1767config STRICT_DEVMEM
1768 bool "Filter access to /dev/mem"
1769 depends on MMU && DEVMEM
527701ed 1770 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
045f6d79
CD
1771 default y if PPC || X86 || ARM64
1772 help
1773 If this option is disabled, you allow userspace (root) access to all
1774 of memory, including kernel and userspace memory. Accidental
1775 access to this is obviously disastrous, but specific access can
1776 be used by people debugging the kernel. Note that with PAT support
1777 enabled, even in this case there are restrictions on /dev/mem
1778 use due to the cache aliasing requirements.
1779
1780 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1781 file only allows userspace access to PCI space and the BIOS code and
1782 data regions. This is sufficient for dosemu and X and all common
1783 users of /dev/mem.
1784
1785 If in doubt, say Y.
1786
1787config IO_STRICT_DEVMEM
1788 bool "Filter I/O access to /dev/mem"
1789 depends on STRICT_DEVMEM
1790 help
1791 If this option is disabled, you allow userspace (root) access to all
1792 io-memory regardless of whether a driver is actively using that
1793 range. Accidental access to this is obviously disastrous, but
1794 specific access can be used by people debugging kernel drivers.
1795
1796 If this option is switched on, the /dev/mem file only allows
1797 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1798 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1799 if the driver using a given range cannot be disabled.
1800
1801 If in doubt, say Y.
1802
1803menu "$(SRCARCH) Debugging"
1804
1805source "arch/$(SRCARCH)/Kconfig.debug"
1806
1807endmenu
1808
1809menu "Kernel Testing and Coverage"
1810
09a74952
CD
1811source "lib/kunit/Kconfig"
1812
8d438288
AM
1813config NOTIFIER_ERROR_INJECTION
1814 tristate "Notifier error injection"
1815 depends on DEBUG_KERNEL
1816 select DEBUG_FS
1817 help
e41e85cc 1818 This option provides the ability to inject artificial errors to
8d438288
AM
1819 specified notifier chain callbacks. It is useful to test the error
1820 handling of notifier call chain failures.
1821
1822 Say N if unsure.
1823
048b9c35
AM
1824config PM_NOTIFIER_ERROR_INJECT
1825 tristate "PM notifier error injection module"
1826 depends on PM && NOTIFIER_ERROR_INJECTION
1827 default m if PM_DEBUG
1828 help
e41e85cc 1829 This option provides the ability to inject artificial errors to
048b9c35
AM
1830 PM notifier chain callbacks. It is controlled through debugfs
1831 interface /sys/kernel/debug/notifier-error-inject/pm
1832
1833 If the notifier call chain should be failed with some events
1834 notified, write the error code to "actions/<notifier event>/error".
1835
1836 Example: Inject PM suspend error (-12 = -ENOMEM)
1837
1838 # cd /sys/kernel/debug/notifier-error-inject/pm/
1839 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1840 # echo mem > /sys/power/state
1841 bash: echo: write error: Cannot allocate memory
1842
1843 To compile this code as a module, choose M here: the module will
1844 be called pm-notifier-error-inject.
1845
1846 If unsure, say N.
1847
d526e85f
BH
1848config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1849 tristate "OF reconfig notifier error injection module"
1850 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dd 1851 help
e41e85cc 1852 This option provides the ability to inject artificial errors to
d526e85f 1853 OF reconfig notifier chain callbacks. It is controlled
08dfb4dd 1854 through debugfs interface under
d526e85f 1855 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
08dfb4dd
AM
1856
1857 If the notifier call chain should be failed with some events
1858 notified, write the error code to "actions/<notifier event>/error".
1859
1860 To compile this code as a module, choose M here: the module will
e12a95f4 1861 be called of-reconfig-notifier-error-inject.
08dfb4dd
AM
1862
1863 If unsure, say N.
1864
02fff96a
NA
1865config NETDEV_NOTIFIER_ERROR_INJECT
1866 tristate "Netdev notifier error injection module"
1867 depends on NET && NOTIFIER_ERROR_INJECTION
1868 help
1869 This option provides the ability to inject artificial errors to
1870 netdevice notifier chain callbacks. It is controlled through debugfs
1871 interface /sys/kernel/debug/notifier-error-inject/netdev
1872
1873 If the notifier call chain should be failed with some events
1874 notified, write the error code to "actions/<notifier event>/error".
1875
1876 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1877
1878 # cd /sys/kernel/debug/notifier-error-inject/netdev
1879 # echo -22 > actions/NETDEV_CHANGEMTU/error
1880 # ip link set eth0 mtu 1024
1881 RTNETLINK answers: Invalid argument
1882
1883 To compile this code as a module, choose M here: the module will
1884 be called netdev-notifier-error-inject.
1885
1886 If unsure, say N.
1887
f1b4bd06 1888config FUNCTION_ERROR_INJECTION
a4412fdd 1889 bool "Fault-injections of functions"
f1b4bd06 1890 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
a4412fdd
SRG
1891 help
1892 Add fault injections into various functions that are annotated with
1893 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1894 value of theses functions. This is useful to test error paths of code.
1895
1896 If unsure, say N
f1b4bd06 1897
6ff1cb35 1898config FAULT_INJECTION
1ab8509a
AM
1899 bool "Fault-injection framework"
1900 depends on DEBUG_KERNEL
329409ae
AM
1901 help
1902 Provide fault-injection framework.
1903 For more details, see Documentation/fault-injection/.
6ff1cb35 1904
8a8b6502 1905config FAILSLAB
1ab8509a
AM
1906 bool "Fault-injection capability for kmalloc"
1907 depends on FAULT_INJECTION
773ff60e 1908 depends on SLAB || SLUB
8a8b6502 1909 help
1ab8509a 1910 Provide fault-injection capability for kmalloc.
8a8b6502 1911
933e312e 1912config FAIL_PAGE_ALLOC
29b46fa3 1913 bool "Fault-injection capability for alloc_pages()"
1ab8509a 1914 depends on FAULT_INJECTION
933e312e 1915 help
1ab8509a 1916 Provide fault-injection capability for alloc_pages().
933e312e 1917
2c739ced
AL
1918config FAULT_INJECTION_USERCOPY
1919 bool "Fault injection capability for usercopy functions"
1920 depends on FAULT_INJECTION
1921 help
1922 Provides fault-injection capability to inject failures
1923 in usercopy functions (copy_from_user(), get_user(), ...).
1924
c17bb495 1925config FAIL_MAKE_REQUEST
86327d19 1926 bool "Fault-injection capability for disk IO"
581d4e28 1927 depends on FAULT_INJECTION && BLOCK
c17bb495 1928 help
1ab8509a 1929 Provide fault-injection capability for disk IO.
c17bb495 1930
581d4e28 1931config FAIL_IO_TIMEOUT
f4d01439 1932 bool "Fault-injection capability for faking disk interrupts"
581d4e28
JA
1933 depends on FAULT_INJECTION && BLOCK
1934 help
1935 Provide fault-injection capability on end IO handling. This
1936 will make the block layer "forget" an interrupt as configured,
1937 thus exercising the error handling.
1938
1939 Only works with drivers that use the generic timeout handling,
9dbbc3b9 1940 for others it won't do anything.
581d4e28 1941
ab51fbab
DB
1942config FAIL_FUTEX
1943 bool "Fault-injection capability for futexes"
1944 select DEBUG_FS
1945 depends on FAULT_INJECTION && FUTEX
1946 help
1947 Provide fault-injection capability for futexes.
1948
f1b4bd06
MP
1949config FAULT_INJECTION_DEBUG_FS
1950 bool "Debugfs entries for fault-injection capabilities"
1951 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1952 help
1953 Enable configuration of fault-injection capabilities via debugfs.
1954
4b1a29a7
MH
1955config FAIL_FUNCTION
1956 bool "Fault-injection capability for functions"
1957 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1958 help
1959 Provide function-based fault-injection capability.
1960 This will allow you to override a specific function with a return
1961 with given return value. As a result, function caller will see
1962 an error value and have to handle it. This is useful to test the
1963 error handling in various subsystems.
1964
f1b4bd06
MP
1965config FAIL_MMC_REQUEST
1966 bool "Fault-injection capability for MMC IO"
1967 depends on FAULT_INJECTION_DEBUG_FS && MMC
6ff1cb35 1968 help
f1b4bd06
MP
1969 Provide fault-injection capability for MMC IO.
1970 This will make the mmc core return data errors. This is
1971 useful to test the error handling in the mmc block device
1972 and to test how the mmc host driver handles retries from
1973 the block device.
1df49008 1974
c782af25
CL
1975config FAIL_SUNRPC
1976 bool "Fault-injection capability for SunRPC"
1977 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1978 help
1979 Provide fault-injection capability for SunRPC and
1980 its consumers.
1981
1df49008
AM
1982config FAULT_INJECTION_STACKTRACE_FILTER
1983 bool "stacktrace filter for fault-injection capabilities"
1984 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
6d690dca 1985 depends on !X86_64
1df49008 1986 select STACKTRACE
7d37cb2c 1987 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1df49008
AM
1988 help
1989 Provide stacktrace filter for fault-injection capabilities
267c4025 1990
09a74952
CD
1991config ARCH_HAS_KCOV
1992 bool
cc3fa840 1993 help
09a74952
CD
1994 An architecture should select this when it can successfully
1995 build and run with CONFIG_KCOV. This typically requires
1996 disabling instrumentation for some early boot code.
cc3fa840 1997
09a74952
CD
1998config CC_HAS_SANCOV_TRACE_PC
1999 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
cc3fa840 2000
cc3fa840 2001
09a74952
CD
2002config KCOV
2003 bool "Code coverage for fuzzing"
2004 depends on ARCH_HAS_KCOV
2005 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
22102f45 2006 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
bece04b5 2007 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
09a74952
CD
2008 select DEBUG_FS
2009 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
22102f45 2010 select OBJTOOL if HAVE_NOINSTR_HACK
09a74952
CD
2011 help
2012 KCOV exposes kernel code coverage information in a form suitable
2013 for coverage-guided fuzzing (randomized testing).
cc3fa840 2014
09a74952
CD
2015 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2016 different machines and across reboots. If you need stable PC values,
2017 disable RANDOMIZE_BASE.
cc3fa840 2018
09a74952 2019 For more details, see Documentation/dev-tools/kcov.rst.
cc3fa840 2020
09a74952
CD
2021config KCOV_ENABLE_COMPARISONS
2022 bool "Enable comparison operands collection by KCOV"
2023 depends on KCOV
2024 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2025 help
2026 KCOV also exposes operands of every comparison in the instrumented
2027 code along with operand sizes and PCs of the comparison instructions.
2028 These operands can be used by fuzzing engines to improve the quality
2029 of fuzzing coverage.
cc3fa840 2030
09a74952
CD
2031config KCOV_INSTRUMENT_ALL
2032 bool "Instrument all code by default"
2033 depends on KCOV
2034 default y
2035 help
2036 If you are doing generic system call fuzzing (like e.g. syzkaller),
2037 then you will want to instrument the whole kernel and you should
2038 say y here. If you are doing more targeted fuzzing (like e.g.
2039 filesystem fuzzing with AFL) then you will want to enable coverage
2040 for more specific subsets of files, and should say n here.
84bc809e 2041
5ff3b30a
AK
2042config KCOV_IRQ_AREA_SIZE
2043 hex "Size of interrupt coverage collection area in words"
2044 depends on KCOV
2045 default 0x40000
2046 help
2047 KCOV uses preallocated per-cpu areas to collect coverage from
2048 soft interrupts. This specifies the size of those areas in the
2049 number of unsigned long words.
2050
d3deafaa
VL
2051menuconfig RUNTIME_TESTING_MENU
2052 bool "Runtime Testing"
908009e8 2053 def_bool y
d3deafaa
VL
2054
2055if RUNTIME_TESTING_MENU
881c5149
DH
2056
2057config LKDTM
2058 tristate "Linux Kernel Dump Test Tool Module"
2059 depends on DEBUG_FS
881c5149
DH
2060 help
2061 This module enables testing of the different dumping mechanisms by
2062 inducing system failures at predefined crash points.
2063 If you don't need it: say N
2064 Choose M here to compile this code as a module. The module will be
2065 called lkdtm.
2066
2067 Documentation on how to use the module can be found in
10ffebbe 2068 Documentation/fault-injection/provoke-crashes.rst
881c5149 2069
d3c0ca49
SV
2070config CPUMASK_KUNIT_TEST
2071 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
c41e8866
SV
2072 depends on KUNIT
2073 default KUNIT_ALL_TESTS
2074 help
2075 Enable to turn on cpumask tests, running at boot or module load time.
2076
d3c0ca49
SV
2077 For more information on KUnit and unit tests in general, please refer
2078 to the KUnit documentation in Documentation/dev-tools/kunit/.
2079
c41e8866
SV
2080 If unsure, say N.
2081
881c5149 2082config TEST_LIST_SORT
ebd09577
DL
2083 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2084 depends on KUNIT
2085 default KUNIT_ALL_TESTS
881c5149
DH
2086 help
2087 Enable this to turn on 'list_sort()' function test. This test is
e327fd7c
GU
2088 executed only once during system boot (so affects only boot time),
2089 or at module load time.
881c5149
DH
2090
2091 If unsure, say N.
2092
6e24628d
IR
2093config TEST_MIN_HEAP
2094 tristate "Min heap test"
2095 depends on DEBUG_KERNEL || m
2096 help
2097 Enable this to turn on min heap function tests. This test is
2098 executed only once during system boot (so affects only boot time),
2099 or at module load time.
2100
2101 If unsure, say N.
2102
c5adae95 2103config TEST_SORT
36f33b56
DL
2104 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2105 depends on KUNIT
2106 default KUNIT_ALL_TESTS
c5adae95 2107 help
5c4e6798
GU
2108 This option enables the self-test function of 'sort()' at boot,
2109 or at module load time.
c5adae95
KF
2110
2111 If unsure, say N.
2112
5086ea4b
MR
2113config TEST_DIV64
2114 tristate "64bit/32bit division and modulo test"
2115 depends on DEBUG_KERNEL || m
2116 help
2117 Enable this to turn on 'do_div()' function test. This test is
2118 executed only once during system boot (so affects only boot time),
2119 or at module load time.
2120
2121 If unsure, say N.
2122
881c5149 2123config KPROBES_SANITY_TEST
dcbb2ee2 2124 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
881c5149
DH
2125 depends on DEBUG_KERNEL
2126 depends on KPROBES
e44e81c5 2127 depends on KUNIT
de3db3f8 2128 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
dcbb2ee2 2129 default KUNIT_ALL_TESTS
881c5149
DH
2130 help
2131 This option provides for testing basic kprobes functionality on
5a6cf77f 2132 boot. Samples of kprobe and kretprobe are inserted and
881c5149
DH
2133 verified for functionality.
2134
2135 Say N if you are unsure.
2136
f4616fab
MH
2137config FPROBE_SANITY_TEST
2138 bool "Self test for fprobe"
2139 depends on DEBUG_KERNEL
2140 depends on FPROBE
2141 depends on KUNIT=y
2142 help
2143 This option will enable testing the fprobe when the system boot.
2144 A series of tests are made to verify that the fprobe is functioning
2145 properly.
2146
2147 Say N if you are unsure.
2148
881c5149
DH
2149config BACKTRACE_SELF_TEST
2150 tristate "Self test for the backtrace code"
2151 depends on DEBUG_KERNEL
881c5149
DH
2152 help
2153 This option provides a kernel module that can be used to test
2154 the kernel stack backtrace code. This option is not useful
2155 for distributions or general kernels, but only for kernel
2156 developers working on architecture code.
2157
2158 Note that if you want to also test saved backtraces, you will
2159 have to enable STACKTRACE as well.
2160
2161 Say N if you are unsure.
2162
914a7b50
ED
2163config TEST_REF_TRACKER
2164 tristate "Self test for reference tracker"
2165 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2166 select REF_TRACKER
2167 help
2168 This option provides a kernel module performing tests
2169 using reference tracker infrastructure.
2170
2171 Say N if you are unsure.
2172
910a742d
ML
2173config RBTREE_TEST
2174 tristate "Red-Black tree test"
7c993e11 2175 depends on DEBUG_KERNEL
910a742d
ML
2176 help
2177 A benchmark measuring the performance of the rbtree library.
2178 Also includes rbtree invariant checks.
2179
4b4f3acc
FB
2180config REED_SOLOMON_TEST
2181 tristate "Reed-Solomon library test"
2182 depends on DEBUG_KERNEL || m
2183 select REED_SOLOMON
2184 select REED_SOLOMON_ENC16
2185 select REED_SOLOMON_DEC16
2186 help
2187 This option enables the self-test function of rslib at boot,
2188 or at module load time.
2189
2190 If unsure, say N.
2191
fff3fd8a
ML
2192config INTERVAL_TREE_TEST
2193 tristate "Interval tree test"
0f789b67 2194 depends on DEBUG_KERNEL
a88cc108 2195 select INTERVAL_TREE
fff3fd8a
ML
2196 help
2197 A benchmark measuring the performance of the interval tree library
2198
623fd807
GT
2199config PERCPU_TEST
2200 tristate "Per cpu operations test"
2201 depends on m && DEBUG_KERNEL
2202 help
2203 Enable this option to build test module which validates per-cpu
2204 operations.
2205
2206 If unsure, say N.
2207
881c5149 2208config ATOMIC64_SELFTEST
55ded955 2209 tristate "Perform an atomic64_t self-test"
881c5149 2210 help
55ded955
GU
2211 Enable this option to test the atomic64_t functions at boot or
2212 at module load time.
881c5149
DH
2213
2214 If unsure, say N.
2215
2216config ASYNC_RAID6_TEST
2217 tristate "Self test for hardware accelerated raid6 recovery"
2218 depends on ASYNC_RAID6_RECOV
2219 select ASYNC_MEMCPY
a7f7f624 2220 help
881c5149
DH
2221 This is a one-shot self test that permutes through the
2222 recovery of all the possible two disk failure scenarios for a
2223 N-disk array. Recovery is performed with the asynchronous
2224 raid6 recovery routines, and will optionally use an offload
2225 engine if one is available.
2226
2227 If unsure, say N.
2228
64d1d77a
AS
2229config TEST_HEXDUMP
2230 tristate "Test functions located in the hexdump module at runtime"
2231
b2ff70a0
MC
2232config STRING_SELFTEST
2233 tristate "Test string functions at runtime"
2234
881c5149
DH
2235config TEST_STRING_HELPERS
2236 tristate "Test functions located in the string_helpers module at runtime"
2237
2238config TEST_KSTRTOX
2239 tristate "Test kstrto*() family of functions at runtime"
2240
707cc728
RV
2241config TEST_PRINTF
2242 tristate "Test printf() family of functions at runtime"
2243
50f530e1
RF
2244config TEST_SCANF
2245 tristate "Test scanf() family of functions at runtime"
2246
5fd003f5
DD
2247config TEST_BITMAP
2248 tristate "Test bitmap_*() family of functions at runtime"
5fd003f5
DD
2249 help
2250 Enable this option to test the bitmap functions at boot.
2251
2252 If unsure, say N.
2253
cfaff0e5
AS
2254config TEST_UUID
2255 tristate "Test functions located in the uuid module at runtime"
2256
ad3d6c72
MW
2257config TEST_XARRAY
2258 tristate "Test the XArray code at runtime"
2259
120b1162 2260config TEST_MAPLE_TREE
845aad0a 2261 depends on DEBUG_KERNEL
120b1162
LH
2262 select DEBUG_MAPLE_TREE
2263 tristate "Test the Maple Tree code at runtime"
2264
7e1e7763 2265config TEST_RHASHTABLE
9d6dbe1b 2266 tristate "Perform selftest on resizable hash table"
7e1e7763
TG
2267 help
2268 Enable this option to test the rhashtable functions at boot.
2269
2270 If unsure, say N.
2271
8ab8ba38
MW
2272config TEST_IDA
2273 tristate "Perform selftest on IDA functions"
2274
44091d29
JP
2275config TEST_PARMAN
2276 tristate "Perform selftest on priority array manager"
44091d29
JP
2277 depends on PARMAN
2278 help
2279 Enable this option to test priority array manager on boot
2280 (or module load).
2281
2282 If unsure, say N.
2283
6aed82de
DL
2284config TEST_IRQ_TIMINGS
2285 bool "IRQ timings selftest"
2286 depends on IRQ_TIMINGS
2287 help
2288 Enable this option to test the irq timings code on boot.
2289
2290 If unsure, say N.
2291
8a6f0b47 2292config TEST_LKM
93e9ef83 2293 tristate "Test module loading with 'hello world' module"
93e9ef83
KC
2294 depends on m
2295 help
2296 This builds the "test_module" module that emits "Hello, world"
2297 on printk when loaded. It is designed to be used for basic
2298 evaluation of the module loading subsystem (for example when
2299 validating module verification). It lacks any extra dependencies,
2300 and will not normally be loaded by the system unless explicitly
2301 requested by name.
2302
2303 If unsure, say N.
2304
c348c163 2305config TEST_BITOPS
6af132f3 2306 tristate "Test module for compilation of bitops operations"
c348c163
JB
2307 depends on m
2308 help
2309 This builds the "test_bitops" module that is much like the
2310 TEST_LKM module except that it does a basic exercise of the
6af132f3
WY
2311 set/clear_bit macros and get_count_order/long to make sure there are
2312 no compiler warnings from C=1 sparse checker or -Wextra
2313 compilations. It has no dependencies and doesn't run or load unless
2314 explicitly requested by name. for example: modprobe test_bitops.
c348c163
JB
2315
2316 If unsure, say N.
2317
3f21a6b7
URS
2318config TEST_VMALLOC
2319 tristate "Test module for stress/performance analysis of vmalloc allocator"
2320 default n
2321 depends on MMU
2322 depends on m
2323 help
2324 This builds the "test_vmalloc" module that should be used for
2325 stress and performance analysis. So, any new change for vmalloc
2326 subsystem can be evaluated from performance and stability point
2327 of view.
2328
2329 If unsure, say N.
2330
3e2a4c18
KC
2331config TEST_USER_COPY
2332 tristate "Test user/kernel boundary protections"
3e2a4c18
KC
2333 depends on m
2334 help
2335 This builds the "test_user_copy" module that runs sanity checks
2336 on the copy_to/from_user infrastructure, making sure basic
2337 user/kernel boundary testing is working. If it fails to load,
2338 a regression has been detected in the user/kernel memory boundary
2339 protections.
2340
2341 If unsure, say N.
2342
64a8946b
AS
2343config TEST_BPF
2344 tristate "Test BPF filter functionality"
98920ba6 2345 depends on m && NET
64a8946b
AS
2346 help
2347 This builds the "test_bpf" module that runs various test vectors
2348 against the BPF interpreter or BPF JIT compiler depending on the
2349 current setting. This is in particular useful for BPF JIT compiler
2350 development, but also to run regression tests against changes in
3c731eba
AS
2351 the interpreter code. It also enables test stubs for eBPF maps and
2352 verifier used by user space verifier testsuite.
64a8946b
AS
2353
2354 If unsure, say N.
2355
509e56b3
MB
2356config TEST_BLACKHOLE_DEV
2357 tristate "Test blackhole netdev functionality"
2358 depends on m && NET
2359 help
2360 This builds the "test_blackhole_dev" module that validates the
2361 data path through this blackhole netdev.
2362
2363 If unsure, say N.
2364
dceeb3e7 2365config FIND_BIT_BENCHMARK
4441fca0 2366 tristate "Test find_bit functions"
4441fca0
YN
2367 help
2368 This builds the "test_find_bit" module that measure find_*_bit()
2369 functions performance.
2370
2371 If unsure, say N.
2372
0a8adf58
KC
2373config TEST_FIRMWARE
2374 tristate "Test firmware loading via userspace interface"
0a8adf58
KC
2375 depends on FW_LOADER
2376 help
2377 This builds the "test_firmware" module that creates a userspace
2378 interface for testing firmware loading. This can be used to
2379 control the triggering of firmware loading without needing an
2380 actual firmware-using device. The contents can be rechecked by
2381 userspace.
2382
2383 If unsure, say N.
2384
9308f2f9
LR
2385config TEST_SYSCTL
2386 tristate "sysctl test driver"
9308f2f9
LR
2387 depends on PROC_SYSCTL
2388 help
2389 This builds the "test_sysctl" module. This driver enables to test the
2390 proc sysctl interfaces available to drivers safely without affecting
2391 production knobs which might alter system functionality.
2392
2393 If unsure, say N.
2394
d2585f51 2395config BITFIELD_KUNIT
dcbb2ee2 2396 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
d2585f51 2397 depends on KUNIT
dcbb2ee2 2398 default KUNIT_ALL_TESTS
d2585f51
VMI
2399 help
2400 Enable this option to test the bitfield functions at boot.
2401
2402 KUnit tests run during boot and output the results to the debug log
2403 in TAP format (http://testanything.org/). Only useful for kernel devs
2404 running the KUnit test harness, and not intended for inclusion into a
2405 production build.
2406
2407 For more information on KUnit and unit tests in general please refer
2408 to the KUnit documentation in Documentation/dev-tools/kunit/.
2409
2410 If unsure, say N.
2411
0acc968f
IB
2412config HASH_KUNIT_TEST
2413 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2414 depends on KUNIT
2415 default KUNIT_ALL_TESTS
2416 help
2417 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2418 integer (<linux/hash.h>) hash functions on boot.
2419
2420 KUnit tests run during boot and output the results to the debug log
2421 in TAP format (https://testanything.org/). Only useful for kernel devs
2422 running the KUnit test harness, and not intended for inclusion into a
2423 production build.
2424
2425 For more information on KUnit and unit tests in general please refer
2426 to the KUnit documentation in Documentation/dev-tools/kunit/.
2427
2428 This is intended to help people writing architecture-specific
2429 optimized versions. If unsure, say N.
2430
5df38ca6 2431config RESOURCE_KUNIT_TEST
dcbb2ee2 2432 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
5df38ca6 2433 depends on KUNIT
dcbb2ee2 2434 default KUNIT_ALL_TESTS
5df38ca6
AS
2435 help
2436 This builds the resource API unit test.
2437 Tests the logic of API provided by resource.c and ioport.h.
2438 For more information on KUnit and unit tests in general please refer
2439 to the KUnit documentation in Documentation/dev-tools/kunit/.
2440
2441 If unsure, say N.
2442
2cb80dbb 2443config SYSCTL_KUNIT_TEST
5f215aab 2444 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2cb80dbb 2445 depends on KUNIT
5f215aab 2446 default KUNIT_ALL_TESTS
2cb80dbb
IZ
2447 help
2448 This builds the proc sysctl unit test, which runs on boot.
2449 Tests the API contract and implementation correctness of sysctl.
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
ea2dd7c0 2455config LIST_KUNIT_TEST
5f215aab 2456 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
ea2dd7c0 2457 depends on KUNIT
5f215aab 2458 default KUNIT_ALL_TESTS
ea2dd7c0
DG
2459 help
2460 This builds the linked list KUnit test suite.
2461 It tests that the API and basic functionality of the list_head type
2462 and associated macros.
2463
2464 KUnit tests run during boot and output the results to the debug log
d89775fc 2465 in TAP format (https://testanything.org/). Only useful for kernel devs
ea2dd7c0
DG
2466 running the KUnit test harness, and not intended for inclusion into a
2467 production build.
2468
2469 For more information on KUnit and unit tests in general please refer
2470 to the KUnit documentation in Documentation/dev-tools/kunit/.
2471
2472 If unsure, say N.
2473
33d599f0
MV
2474config LINEAR_RANGES_TEST
2475 tristate "KUnit test for linear_ranges"
2476 depends on KUNIT
2477 select LINEAR_RANGES
2478 help
2479 This builds the linear_ranges unit test, which runs on boot.
2480 Tests the linear_ranges logic correctness.
2481 For more information on KUnit and unit tests in general please refer
7546861a
AS
2482 to the KUnit documentation in Documentation/dev-tools/kunit/.
2483
2484 If unsure, say N.
2485
2486config CMDLINE_KUNIT_TEST
dcbb2ee2 2487 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
7546861a 2488 depends on KUNIT
dcbb2ee2 2489 default KUNIT_ALL_TESTS
7546861a
AS
2490 help
2491 This builds the cmdline API unit test.
2492 Tests the logic of API provided by cmdline.c.
2493 For more information on KUnit and unit tests in general please refer
33d599f0
MV
2494 to the KUnit documentation in Documentation/dev-tools/kunit/.
2495
2496 If unsure, say N.
2497
6d511020 2498config BITS_TEST
dcbb2ee2 2499 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
6d511020 2500 depends on KUNIT
dcbb2ee2 2501 default KUNIT_ALL_TESTS
6d511020
RF
2502 help
2503 This builds the bits unit test.
2504 Tests the logic of macros defined in bits.h.
2505 For more information on KUnit and unit tests in general please refer
2506 to the KUnit documentation in Documentation/dev-tools/kunit/.
2507
2508 If unsure, say N.
2509
1f9f78b1
OG
2510config SLUB_KUNIT_TEST
2511 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2512 depends on SLUB_DEBUG && KUNIT
2513 default KUNIT_ALL_TESTS
2514 help
2515 This builds SLUB allocator unit test.
2516 Tests SLUB cache debugging functionality.
2517 For more information on KUnit and unit tests in general please refer
2518 to the KUnit documentation in Documentation/dev-tools/kunit/.
2519
2520 If unsure, say N.
2521
b6c75c4a
TP
2522config RATIONAL_KUNIT_TEST
2523 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
8ba739ed 2524 depends on KUNIT && RATIONAL
b6c75c4a
TP
2525 default KUNIT_ALL_TESTS
2526 help
2527 This builds the rational math unit test.
2528 For more information on KUnit and unit tests in general please refer
2529 to the KUnit documentation in Documentation/dev-tools/kunit/.
2530
2531 If unsure, say N.
2532
bb95ebbe
KC
2533config MEMCPY_KUNIT_TEST
2534 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2535 depends on KUNIT
2536 default KUNIT_ALL_TESTS
2537 help
2538 Builds unit tests for memcpy(), memmove(), and memset() functions.
2539 For more information on KUnit and unit tests in general please refer
2540 to the KUnit documentation in Documentation/dev-tools/kunit/.
2541
2542 If unsure, say N.
2543
addbeea6
BVA
2544config IS_SIGNED_TYPE_KUNIT_TEST
2545 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2546 depends on KUNIT
2547 default KUNIT_ALL_TESTS
2548 help
2549 Builds unit tests for the is_signed_type() macro.
2550
2551 For more information on KUnit and unit tests in general please refer
2552 to the KUnit documentation in Documentation/dev-tools/kunit/.
2553
2554 If unsure, say N.
2555
617f55e2
KC
2556config OVERFLOW_KUNIT_TEST
2557 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2558 depends on KUNIT
2559 default KUNIT_ALL_TESTS
2560 help
2561 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2562 related functions.
2563
2564 For more information on KUnit and unit tests in general please refer
2565 to the KUnit documentation in Documentation/dev-tools/kunit/.
2566
2567 If unsure, say N.
2568
02788ebc
KC
2569config STACKINIT_KUNIT_TEST
2570 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2571 depends on KUNIT
2572 default KUNIT_ALL_TESTS
2573 help
2574 Test if the kernel is zero-initializing stack variables and
2575 padding. Coverage is controlled by compiler flags,
2576 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2577 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2578 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2579
875bfd52
KC
2580config FORTIFY_KUNIT_TEST
2581 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2582 depends on KUNIT && FORTIFY_SOURCE
2583 default KUNIT_ALL_TESTS
2584 help
2585 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2586 by the str*() and mem*() family of functions. For testing runtime
2587 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2588
724c299c
ME
2589config HW_BREAKPOINT_KUNIT_TEST
2590 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2591 depends on HAVE_HW_BREAKPOINT
2592 depends on KUNIT=y
2593 default KUNIT_ALL_TESTS
2594 help
2595 Tests for hw_breakpoint constraints accounting.
2596
2597 If unsure, say N.
2598
41eefc46
KC
2599config STRSCPY_KUNIT_TEST
2600 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2601 depends on KUNIT
2602 default KUNIT_ALL_TESTS
2603
fb3d88ab
KC
2604config SIPHASH_KUNIT_TEST
2605 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2606 depends on KUNIT
2607 default KUNIT_ALL_TESTS
2608 help
2609 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2610 functions on boot (or module load).
2611
2612 This is intended to help people writing architecture-specific
2613 optimized versions. If unsure, say N.
2614
e704f93a
DR
2615config TEST_UDELAY
2616 tristate "udelay test driver"
e704f93a
DR
2617 help
2618 This builds the "udelay_test" module that helps to make sure
2619 that udelay() is working properly.
2620
2621 If unsure, say N.
2622
2bf9e0ab
IM
2623config TEST_STATIC_KEYS
2624 tristate "Test static keys"
579e1acb
JB
2625 depends on m
2626 help
2bf9e0ab 2627 Test the static key interfaces.
579e1acb
JB
2628
2629 If unsure, say N.
2630
683263a5
JC
2631config TEST_DYNAMIC_DEBUG
2632 tristate "Test DYNAMIC_DEBUG"
2633 depends on DYNAMIC_DEBUG
2634 help
2635 This module registers a tracer callback to count enabled
2636 pr_debugs in a 'do_debugging' function, then alters their
2637 enablements, calls the function, and compares counts.
2638
2639 If unsure, say N.
2640
d9c6a72d
LR
2641config TEST_KMOD
2642 tristate "kmod stress tester"
d9c6a72d 2643 depends on m
d9c6a72d 2644 depends on NETDEVICES && NET_CORE && INET # for TUN
ae3d6a32 2645 depends on BLOCK
bbd2e05f 2646 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
d9c6a72d
LR
2647 select TEST_LKM
2648 select XFS_FS
2649 select TUN
2650 select BTRFS_FS
2651 help
2652 Test the kernel's module loading mechanism: kmod. kmod implements
2653 support to load modules using the Linux kernel's usermode helper.
2654 This test provides a series of tests against kmod.
2655
2656 Although technically you can either build test_kmod as a module or
2657 into the kernel we disallow building it into the kernel since
2658 it stress tests request_module() and this will very likely cause
2659 some issues by taking over precious threads available from other
2660 module load requests, ultimately this could be fatal.
2661
2662 To run tests run:
2663
2664 tools/testing/selftests/kmod/kmod.sh --help
2665
2666 If unsure, say N.
2667
e4dace36
FF
2668config TEST_DEBUG_VIRTUAL
2669 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2670 depends on DEBUG_VIRTUAL
2671 help
2672 Test the kernel's ability to detect incorrect calls to
2673 virt_to_phys() done against the non-linear part of the
2674 kernel's virtual address map.
2675
2676 If unsure, say N.
2677
ce76d938
AS
2678config TEST_MEMCAT_P
2679 tristate "Test memcat_p() helper function"
2680 help
2681 Test the memcat_p() helper for correctly merging two
2682 pointer arrays together.
2683
2684 If unsure, say N.
2685
a2818ee4
JL
2686config TEST_LIVEPATCH
2687 tristate "Test livepatching"
2688 default n
bae05437 2689 depends on DYNAMIC_DEBUG
a2818ee4
JL
2690 depends on LIVEPATCH
2691 depends on m
2692 help
2693 Test kernel livepatching features for correctness. The tests will
2694 load test modules that will be livepatched in various scenarios.
2695
2696 To run all the livepatching tests:
2697
2698 make -C tools/testing/selftests TARGETS=livepatch run_tests
2699
2700 Alternatively, individual tests may be invoked:
2701
2702 tools/testing/selftests/livepatch/test-callbacks.sh
2703 tools/testing/selftests/livepatch/test-livepatch.sh
2704 tools/testing/selftests/livepatch/test-shadow-vars.sh
2705
2706 If unsure, say N.
2707
0a020d41
JP
2708config TEST_OBJAGG
2709 tristate "Perform selftest on object aggreration manager"
2710 default n
2711 depends on OBJAGG
2712 help
2713 Enable this option to test object aggregation manager on boot
2714 (or module load).
2715
5015a300
AP
2716config TEST_MEMINIT
2717 tristate "Test heap/page initialization"
2718 help
2719 Test if the kernel is zero-initializing heap and page allocations.
2720 This can be useful to test init_on_alloc and init_on_free features.
2721
2722 If unsure, say N.
2723
b2ef9f5a
RC
2724config TEST_HMM
2725 tristate "Test HMM (Heterogeneous Memory Management)"
2726 depends on TRANSPARENT_HUGEPAGE
2727 depends on DEVICE_PRIVATE
2728 select HMM_MIRROR
2729 select MMU_NOTIFIER
2730 help
2731 This is a pseudo device driver solely for testing HMM.
2732 Say M here if you want to build the HMM test module.
2733 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2734
2735 If unsure, say N.
2736
e320d301
MWO
2737config TEST_FREE_PAGES
2738 tristate "Test freeing pages"
2739 help
2740 Test that a memory leak does not occur due to a race between
2741 freeing a block of pages and a speculative page reference.
2742 Loading this module is safe if your kernel has the bug fixed.
2743 If the bug is not fixed, it will leak gigabytes of memory and
2744 probably OOM your system.
2745
4185b3b9
PA
2746config TEST_FPU
2747 tristate "Test floating point operations in kernel space"
2748 depends on X86 && !KCOV_INSTRUMENT_ALL
2749 help
2750 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2751 which will trigger a sequence of floating point operations. This is used
2752 for self-testing floating point control register setting in
2753 kernel_fpu_begin().
2754
2755 If unsure, say N.
2756
1253b9b8
PM
2757config TEST_CLOCKSOURCE_WATCHDOG
2758 tristate "Test clocksource watchdog in kernel space"
2759 depends on CLOCKSOURCE_WATCHDOG
2760 help
2761 Enable this option to create a kernel module that will trigger
2762 a test of the clocksource watchdog. This module may be loaded
2763 via modprobe or insmod in which case it will run upon being
2764 loaded, or it may be built in, in which case it will run
2765 shortly after boot.
2766
2767 If unsure, say N.
2768
d3deafaa 2769endif # RUNTIME_TESTING_MENU
cc3fa840 2770
dce44566
AK
2771config ARCH_USE_MEMTEST
2772 bool
2773 help
2774 An architecture should select this when it uses early_memtest()
2775 during boot process.
2776
cc3fa840
RD
2777config MEMTEST
2778 bool "Memtest"
dce44566 2779 depends on ARCH_USE_MEMTEST
a7f7f624 2780 help
cc3fa840 2781 This option adds a kernel parameter 'memtest', which allows memtest
dce44566 2782 to be set and executed.
cc3fa840
RD
2783 memtest=0, mean disabled; -- default
2784 memtest=1, mean do 1 test pattern;
2785 ...
2786 memtest=17, mean do 17 test patterns.
2787 If you are unsure how to answer this question, answer N.
2788
21266be9 2789
06ec64b8 2790
af9ca6f9
BB
2791config HYPERV_TESTING
2792 bool "Microsoft Hyper-V driver testing"
2793 default n
2794 depends on HYPERV && DEBUG_FS
2795 help
2796 Select this option to enable Hyper-V vmbus testing.
2797
045f6d79
CD
2798endmenu # "Kernel Testing and Coverage"
2799
2f7ab126
MO
2800menu "Rust hacking"
2801
2802config RUST_DEBUG_ASSERTIONS
2803 bool "Debug assertions"
2804 depends on RUST
2805 help
2806 Enables rustc's `-Cdebug-assertions` codegen option.
2807
2808 This flag lets you turn `cfg(debug_assertions)` conditional
2809 compilation on or off. This can be used to enable extra debugging
2810 code in development but not in production. For example, it controls
2811 the behavior of the standard library's `debug_assert!` macro.
2812
2813 Note that this will apply to all Rust code, including `core`.
2814
2815 If unsure, say N.
2816
2817config RUST_OVERFLOW_CHECKS
2818 bool "Overflow checks"
2819 default y
2820 depends on RUST
2821 help
2822 Enables rustc's `-Coverflow-checks` codegen option.
2823
2824 This flag allows you to control the behavior of runtime integer
2825 overflow. When overflow-checks are enabled, a Rust panic will occur
2826 on overflow.
2827
2828 Note that this will apply to all Rust code, including `core`.
2829
2830 If unsure, say Y.
2831
ecaa6ddf
GG
2832config RUST_BUILD_ASSERT_ALLOW
2833 bool "Allow unoptimized build-time assertions"
2834 depends on RUST
2835 help
2836 Controls how are `build_error!` and `build_assert!` handled during build.
2837
2838 If calls to them exist in the binary, it may indicate a violated invariant
2839 or that the optimizer failed to verify the invariant during compilation.
2840
2841 This should not happen, thus by default the build is aborted. However,
2842 as an escape hatch, you can choose Y here to ignore them during build
2843 and let the check be carried at runtime (with `panic!` being called if
2844 the check fails).
2845
2846 If unsure, say N.
2847
2f7ab126
MO
2848endmenu # "Rust"
2849
75442fb0
MCC
2850source "Documentation/Kconfig"
2851
06ec64b8 2852endmenu # Kernel hacking