modpost: Join broken long printed messages
[linux-block.git] / lib / Kconfig.debug
CommitLineData
ec8f24b7 1# SPDX-License-Identifier: GPL-2.0-only
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2menu "Kernel hacking"
3
604ff0dc 4menu "printk and dmesg options"
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5
6config PRINTK_TIME
7 bool "Show timing information on printks"
d3b8b6e5 8 depends on PRINTK
1da177e4 9 help
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10 Selecting this option causes time stamps of the printk()
11 messages to be added to the output of the syslog() system
12 call and at the console.
13
14 The timestamp is always recorded internally, and exported
15 to /dev/kmsg. This flag just specifies if the timestamp should
16 be included, not that the timestamp is recorded.
17
18 The behavior is also controlled by the kernel command line
8c27ceff 19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
1da177e4 20
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21config PRINTK_CALLER
22 bool "Show caller information on printks"
23 depends on PRINTK
24 help
25 Selecting this option causes printk() to add a caller "thread id" (if
26 in task context) or a caller "processor id" (if not in task context)
27 to every message.
28
29 This option is intended for environments where multiple threads
30 concurrently call printk() for many times, for it is difficult to
31 interpret without knowing where these lines (or sometimes individual
32 line which was divided into multiple lines due to race) came from.
33
34 Since toggling after boot makes the code racy, currently there is
35 no option to enable/disable at the kernel command line parameter or
36 sysfs interface.
37
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38config STACKTRACE_BUILD_ID
39 bool "Show build ID information in stacktraces"
40 depends on PRINTK
41 help
42 Selecting this option adds build ID information for symbols in
43 stacktraces printed with the printk format '%p[SR]b'.
44
45 This option is intended for distros where debuginfo is not easily
46 accessible but can be downloaded given the build ID of the vmlinux or
47 kernel module where the function is located.
48
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49config CONSOLE_LOGLEVEL_DEFAULT
50 int "Default console loglevel (1-15)"
51 range 1 15
52 default "7"
53 help
54 Default loglevel to determine what will be printed on the console.
55
56 Setting a default here is equivalent to passing in loglevel=<x> in
57 the kernel bootargs. loglevel=<x> continues to override whatever
58 value is specified here as well.
59
50f4d9bd 60 Note: This does not affect the log level of un-prefixed printk()
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61 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
62 option.
63
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64config CONSOLE_LOGLEVEL_QUIET
65 int "quiet console loglevel (1-15)"
66 range 1 15
67 default "4"
68 help
69 loglevel to use when "quiet" is passed on the kernel commandline.
70
71 When "quiet" is passed on the kernel commandline this loglevel
72 will be used as the loglevel. IOW passing "quiet" will be the
73 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
74
42a9dc0b 75config MESSAGE_LOGLEVEL_DEFAULT
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76 int "Default message log level (1-7)"
77 range 1 7
78 default "4"
79 help
80 Default log level for printk statements with no specified priority.
81
82 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83 that are auditing their logs closely may want to set it to a lower
84 priority.
85
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86 Note: This does not affect what message level gets printed on the console
87 by default. To change that, use loglevel=<x> in the kernel bootargs,
88 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
89
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90config BOOT_PRINTK_DELAY
91 bool "Delay each boot printk message by N milliseconds"
92 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
93 help
94 This build option allows you to read kernel boot messages
95 by inserting a short delay after each one. The delay is
96 specified in milliseconds on the kernel command line,
97 using "boot_delay=N".
98
99 It is likely that you would also need to use "lpj=M" to preset
100 the "loops per jiffie" value.
101 See a previous boot log for the "lpj" value to use for your
102 system, and then set "lpj=M" before setting "boot_delay=N".
103 NOTE: Using this option may adversely affect SMP systems.
104 I.e., processors other than the first one may not boot up.
105 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106 what it believes to be lockup conditions.
107
108config DYNAMIC_DEBUG
109 bool "Enable dynamic printk() support"
110 default n
111 depends on PRINTK
239a5791 112 depends on (DEBUG_FS || PROC_FS)
ceabef7d 113 select DYNAMIC_DEBUG_CORE
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114 help
115
116 Compiles debug level messages into the kernel, which would not
117 otherwise be available at runtime. These messages can then be
118 enabled/disabled based on various levels of scope - per source file,
119 function, module, format string, and line number. This mechanism
120 implicitly compiles in all pr_debug() and dev_dbg() calls, which
121 enlarges the kernel text size by about 2%.
122
123 If a source file is compiled with DEBUG flag set, any
124 pr_debug() calls in it are enabled by default, but can be
125 disabled at runtime as below. Note that DEBUG flag is
126 turned on by many CONFIG_*DEBUG* options.
127
128 Usage:
129
130 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
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131 which is contained in the 'debugfs' filesystem or procfs.
132 Thus, the debugfs or procfs filesystem must first be mounted before
133 making use of this feature.
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134 We refer the control file as: <debugfs>/dynamic_debug/control. This
135 file contains a list of the debug statements that can be enabled. The
136 format for each line of the file is:
137
138 filename:lineno [module]function flags format
139
140 filename : source file of the debug statement
141 lineno : line number of the debug statement
142 module : module that contains the debug statement
143 function : function that contains the debug statement
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144 flags : '=p' means the line is turned 'on' for printing
145 format : the format used for the debug statement
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146
147 From a live system:
148
149 nullarbor:~ # cat <debugfs>/dynamic_debug/control
150 # filename:lineno [module]function flags format
151 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154
155 Example usage:
156
157 // enable the message at line 1603 of file svcsock.c
158 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159 <debugfs>/dynamic_debug/control
160
161 // enable all the messages in file svcsock.c
162 nullarbor:~ # echo -n 'file svcsock.c +p' >
163 <debugfs>/dynamic_debug/control
164
165 // enable all the messages in the NFS server module
166 nullarbor:~ # echo -n 'module nfsd +p' >
167 <debugfs>/dynamic_debug/control
168
169 // enable all 12 messages in the function svc_process()
170 nullarbor:~ # echo -n 'func svc_process +p' >
171 <debugfs>/dynamic_debug/control
172
173 // disable all 12 messages in the function svc_process()
174 nullarbor:~ # echo -n 'func svc_process -p' >
175 <debugfs>/dynamic_debug/control
176
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177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
178 information.
604ff0dc 179
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180config DYNAMIC_DEBUG_CORE
181 bool "Enable core function of dynamic debug support"
182 depends on PRINTK
183 depends on (DEBUG_FS || PROC_FS)
184 help
185 Enable core functional support of dynamic debug. It is useful
186 when you want to tie dynamic debug to your kernel modules with
187 DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188 the case of embedded system where the kernel image size is
189 sensitive for people.
190
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191config SYMBOLIC_ERRNAME
192 bool "Support symbolic error names in printf"
193 default y if PRINTK
194 help
195 If you say Y here, the kernel's printf implementation will
196 be able to print symbolic error names such as ENOSPC instead
197 of the number 28. It makes the kernel image slightly larger
198 (about 3KB), but can make the kernel logs easier to read.
199
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200config DEBUG_BUGVERBOSE
201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
203 default y
204 help
205 Say Y here to make BUG() panics output the file name and line number
206 of the BUG call as well as the EIP and oops trace. This aids
207 debugging but costs about 70-100K of memory.
208
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209endmenu # "printk and dmesg options"
210
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211config DEBUG_KERNEL
212 bool "Kernel debugging"
213 help
214 Say Y here if you are developing drivers or trying to debug and
215 identify kernel problems.
216
217config DEBUG_MISC
218 bool "Miscellaneous debug code"
219 default DEBUG_KERNEL
220 depends on DEBUG_KERNEL
221 help
222 Say Y here if you need to enable miscellaneous debug code that should
223 be under a more specific debug option but isn't.
224
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225menu "Compile-time checks and compiler options"
226
227config DEBUG_INFO
f9b3cd24 228 bool
6dfc0665 229 help
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230 A kernel debug info option other than "None" has been selected
231 in the "Debug information" choice below, indicating that debug
232 information will be generated for build targets.
233
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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)
402 default 1024 if !64BIT
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403 default 2048 if 64BIT
404 help
921757bc 405 Tell the compiler to warn at build time for stack frames larger than this.
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406 Setting this too low will cause a lot of warnings.
407 Setting it to 0 disables the warning.
35bb5b1e 408
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409config STRIP_ASM_SYMS
410 bool "Strip assembler-generated symbols during link"
411 default n
412 help
413 Strip internal assembler-generated symbols during a link (symbols
414 that look like '.Lxxx') so they don't pollute the output of
415 get_wchan() and suchlike.
416
1873e870 417config READABLE_ASM
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418 bool "Generate readable assembler code"
419 depends on DEBUG_KERNEL
7d73c3e9 420 depends on CC_IS_GCC
bf4735a4 421 help
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422 Disable some compiler optimizations that tend to generate human unreadable
423 assembler output. This may make the kernel slightly slower, but it helps
424 to keep kernel developers who have to stare a lot at assembler listings
425 sane.
bf4735a4 426
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427config HEADERS_INSTALL
428 bool "Install uapi headers to usr/include"
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429 depends on !UML
430 help
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431 This option will install uapi headers (headers exported to user-space)
432 into the usr/include directory for use during the kernel build.
433 This is unneeded for building the kernel itself, but needed for some
434 user-space program samples. It is also needed by some features such
435 as uapi header sanity checks.
436
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437config DEBUG_SECTION_MISMATCH
438 bool "Enable full Section mismatch analysis"
7d73c3e9 439 depends on CC_IS_GCC
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440 help
441 The section mismatch analysis checks if there are illegal
442 references from one section to another section.
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443 During linktime or runtime, some sections are dropped;
444 any use of code/data previously in these sections would
91341d4b 445 most likely result in an oops.
e809ab01 446 In the code, functions and variables are annotated with
0db0628d 447 __init,, etc. (see the full list in include/linux/init.h),
d6fbfa4f 448 which results in the code/data being placed in specific sections.
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449 The section mismatch analysis is always performed after a full
450 kernel build, and enabling this option causes the following
b7dca6dd 451 additional step to occur:
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452 - Add the option -fno-inline-functions-called-once to gcc commands.
453 When inlining a function annotated with __init in a non-init
454 function, we would lose the section information and thus
91341d4b 455 the analysis would not catch the illegal reference.
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456 This option tells gcc to inline less (but it does result in
457 a larger kernel).
91341d4b 458
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459config SECTION_MISMATCH_WARN_ONLY
460 bool "Make section mismatch errors non-fatal"
461 default y
462 help
463 If you say N here, the build process will fail if there are any
464 section mismatch, instead of just throwing warnings.
465
466 If unsure, say Y.
467
cf536e18 468config DEBUG_FORCE_FUNCTION_ALIGN_64B
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469 bool "Force all function address 64B aligned"
470 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
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471 help
472 There are cases that a commit from one domain changes the function
473 address alignment of other domains, and cause magic performance
474 bump (regression or improvement). Enable this option will help to
475 verify if the bump is caused by function alignment changes, while
476 it will slightly increase the kernel size and affect icache usage.
477
478 It is mainly for debug and performance tuning use.
479
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480#
481# Select this config option from the architecture Kconfig, if it
482# is preferred to always offer frame pointers as a config
483# option on the architecture (regardless of KERNEL_DEBUG):
484#
485config ARCH_WANT_FRAME_POINTERS
486 bool
f346f4b3 487
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488config FRAME_POINTER
489 bool "Compile the kernel with frame pointers"
a687a533 490 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
6dfc0665 491 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
a304e1b8 492 help
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493 If you say Y here the resulting kernel image will be slightly
494 larger and slower, but it gives very useful debugging information
495 in case of kernel bugs. (precise oopses/stacktraces/warnings)
a304e1b8 496
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497config OBJTOOL
498 bool
499
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500config STACK_VALIDATION
501 bool "Compile-time stack metadata validation"
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502 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
503 select OBJTOOL
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504 default n
505 help
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506 Validate frame pointer rules at compile-time. This helps ensure that
507 runtime stack traces are more reliable.
ee9f8fce 508
b9ab5ebb 509 For more information, see
d6a21f2d 510 tools/objtool/Documentation/objtool.txt.
b9ab5ebb 511
0f620cef 512config NOINSTR_VALIDATION
6804c1af 513 bool
489e355b 514 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
03f16cd0 515 select OBJTOOL
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516 default y
517
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518config VMLINUX_MAP
519 bool "Generate vmlinux.map file when linking"
520 depends on EXPERT
521 help
522 Selecting this option will pass "-Map=vmlinux.map" to ld
523 when linking vmlinux. That file can be useful for verifying
524 and debugging magic section games, and for seeing which
525 pieces of code get eliminated with
526 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
527
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528config DEBUG_FORCE_WEAK_PER_CPU
529 bool "Force weak per-cpu definitions"
530 depends on DEBUG_KERNEL
8446f1d3 531 help
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532 s390 and alpha require percpu variables in modules to be
533 defined weak to work around addressing range issue which
534 puts the following two restrictions on percpu variable
535 definitions.
8446f1d3 536
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537 1. percpu symbols must be unique whether static or not
538 2. percpu variables can't be defined inside a function
8446f1d3 539
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540 To ensure that generic code follows the above rules, this
541 option forces all percpu variables to be defined as weak.
5f329089 542
6dfc0665 543endmenu # "Compiler options"
8446f1d3 544
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545menu "Generic Kernel Debugging Instruments"
546
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547config MAGIC_SYSRQ
548 bool "Magic SysRq key"
549 depends on !UML
550 help
551 If you say Y here, you will have some control over the system even
552 if the system crashes for example during kernel debugging (e.g., you
553 will be able to flush the buffer cache to disk, reboot the system
554 immediately or dump some status information). This is accomplished
555 by pressing various keys while holding SysRq (Alt+PrintScreen). It
556 also works on a serial console (on PC hardware at least), if you
557 send a BREAK and then within 5 seconds a command keypress. The
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558 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
559 Don't say Y unless you really know what this hack does.
8446f1d3 560
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561config MAGIC_SYSRQ_DEFAULT_ENABLE
562 hex "Enable magic SysRq key functions by default"
563 depends on MAGIC_SYSRQ
564 default 0x1
565 help
566 Specifies which SysRq key functions are enabled by default.
567 This may be set to 1 or 0 to enable or disable them all, or
f8998c22 568 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
8eaede49 569
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570config MAGIC_SYSRQ_SERIAL
571 bool "Enable magic SysRq key over serial"
572 depends on MAGIC_SYSRQ
573 default y
574 help
575 Many embedded boards have a disconnected TTL level serial which can
576 generate some garbage that can lead to spurious false sysrq detects.
577 This option allows you to decide whether you want to enable the
578 magic SysRq key.
579
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580config MAGIC_SYSRQ_SERIAL_SEQUENCE
581 string "Char sequence that enables magic SysRq over serial"
582 depends on MAGIC_SYSRQ_SERIAL
583 default ""
584 help
585 Specifies a sequence of characters that can follow BREAK to enable
586 SysRq on a serial console.
587
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588 If unsure, leave an empty string and the option will not be enabled.
589
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590config DEBUG_FS
591 bool "Debug Filesystem"
592 help
593 debugfs is a virtual file system that kernel developers use to put
594 debugging files into. Enable this option to be able to read and
595 write to these files.
596
597 For detailed documentation on the debugfs API, see
598 Documentation/filesystems/.
599
600 If unsure, say N.
601
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602choice
603 prompt "Debugfs default access"
604 depends on DEBUG_FS
605 default DEBUG_FS_ALLOW_ALL
606 help
607 This selects the default access restrictions for debugfs.
608 It can be overridden with kernel command line option
609 debugfs=[on,no-mount,off]. The restrictions apply for API access
610 and filesystem registration.
611
612config DEBUG_FS_ALLOW_ALL
613 bool "Access normal"
614 help
615 No restrictions apply. Both API and filesystem registration
616 is on. This is the normal default operation.
617
618config DEBUG_FS_DISALLOW_MOUNT
619 bool "Do not register debugfs as filesystem"
620 help
621 The API is open but filesystem is not loaded. Clients can still do
622 their work and read with debug tools that do not need
623 debugfs filesystem.
624
625config DEBUG_FS_ALLOW_NONE
626 bool "No access"
627 help
628 Access is off. Clients get -PERM when trying to create nodes in
629 debugfs tree and debugfs is not registered as a filesystem.
630 Client can then back-off or continue without debugfs access.
631
632endchoice
633
6210b640 634source "lib/Kconfig.kgdb"
6210b640 635source "lib/Kconfig.ubsan"
2645d432 636source "lib/Kconfig.kcsan"
6210b640
CD
637
638endmenu
639
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640menu "Networking Debugging"
641
642source "net/Kconfig.debug"
643
644endmenu # "Networking Debugging"
c66d7a27 645
0610c8a8 646menu "Memory Debugging"
fef2c9bc 647
8636a1f9 648source "mm/Kconfig.debug"
fef2c9bc 649
0610c8a8
DH
650config DEBUG_OBJECTS
651 bool "Debug object operations"
652 depends on DEBUG_KERNEL
9c44bc03 653 help
0610c8a8
DH
654 If you say Y here, additional code will be inserted into the
655 kernel to track the life time of various objects and validate
656 the operations on those objects.
9c44bc03 657
0610c8a8
DH
658config DEBUG_OBJECTS_SELFTEST
659 bool "Debug objects selftest"
660 depends on DEBUG_OBJECTS
661 help
662 This enables the selftest of the object debug code.
9c44bc03 663
0610c8a8
DH
664config DEBUG_OBJECTS_FREE
665 bool "Debug objects in freed memory"
666 depends on DEBUG_OBJECTS
667 help
668 This enables checks whether a k/v free operation frees an area
669 which contains an object which has not been deactivated
670 properly. This can make kmalloc/kfree-intensive workloads
671 much slower.
3ac7fe5a 672
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673config DEBUG_OBJECTS_TIMERS
674 bool "Debug timer objects"
675 depends on DEBUG_OBJECTS
676 help
677 If you say Y here, additional code will be inserted into the
678 timer routines to track the life time of timer objects and
679 validate the timer operations.
680
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681config DEBUG_OBJECTS_WORK
682 bool "Debug work objects"
683 depends on DEBUG_OBJECTS
684 help
685 If you say Y here, additional code will be inserted into the
686 work queue routines to track the life time of work objects and
687 validate the work operations.
688
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689config DEBUG_OBJECTS_RCU_HEAD
690 bool "Debug RCU callbacks objects"
fc2ecf7e 691 depends on DEBUG_OBJECTS
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MD
692 help
693 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
694
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695config DEBUG_OBJECTS_PERCPU_COUNTER
696 bool "Debug percpu counter objects"
697 depends on DEBUG_OBJECTS
698 help
699 If you say Y here, additional code will be inserted into the
700 percpu counter routines to track the life time of percpu counter
701 objects and validate the percpu counter operations.
702
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703config DEBUG_OBJECTS_ENABLE_DEFAULT
704 int "debug_objects bootup default value (0-1)"
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705 range 0 1
706 default "1"
707 depends on DEBUG_OBJECTS
708 help
709 Debug objects boot parameter default value
3ae70205 710
5035ebc6 711config SHRINKER_DEBUG
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RG
712 bool "Enable shrinker debugging support"
713 depends on DEBUG_FS
714 help
715 Say Y to enable the shrinker debugfs interface which provides
716 visibility into the kernel memory shrinkers subsystem.
717 Disable it to avoid an extra memory footprint.
718
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719config HAVE_DEBUG_KMEMLEAK
720 bool
721
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722config DEBUG_KMEMLEAK
723 bool "Kernel memory leak detector"
525c1f92 724 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
79e0d9bd 725 select DEBUG_FS
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726 select STACKTRACE if STACKTRACE_SUPPORT
727 select KALLSYMS
b60e26a2 728 select CRC32
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CM
729 help
730 Say Y here if you want to enable the memory leak
731 detector. The memory allocation/freeing is traced in a way
732 similar to the Boehm's conservative garbage collector, the
733 difference being that the orphan objects are not freed but
734 only shown in /sys/kernel/debug/kmemleak. Enabling this
735 feature will introduce an overhead to memory
700199b0 736 allocations. See Documentation/dev-tools/kmemleak.rst for more
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CM
737 details.
738
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DH
739 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
740 of finding leaks due to the slab objects poisoning.
741
742 In order to access the kmemleak file, debugfs needs to be
743 mounted (usually at /sys/kernel/debug).
744
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CM
745config DEBUG_KMEMLEAK_MEM_POOL_SIZE
746 int "Kmemleak memory pool size"
0610c8a8 747 depends on DEBUG_KMEMLEAK
c59180ae 748 range 200 1000000
b751c52b 749 default 16000
0610c8a8
DH
750 help
751 Kmemleak must track all the memory allocations to avoid
752 reporting false positives. Since memory may be allocated or
c5665868
CM
753 freed before kmemleak is fully initialised, use a static pool
754 of metadata objects to track such callbacks. After kmemleak is
755 fully initialised, this memory pool acts as an emergency one
756 if slab allocations fail.
0610c8a8
DH
757
758config DEBUG_KMEMLEAK_TEST
759 tristate "Simple test for the kernel memory leak detector"
760 depends on DEBUG_KMEMLEAK && m
761 help
762 This option enables a module that explicitly leaks memory.
763
764 If unsure, say N.
765
766config DEBUG_KMEMLEAK_DEFAULT_OFF
767 bool "Default kmemleak to off"
768 depends on DEBUG_KMEMLEAK
769 help
770 Say Y here to disable kmemleak by default. It can then be enabled
771 on the command line via kmemleak=on.
772
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773config DEBUG_KMEMLEAK_AUTO_SCAN
774 bool "Enable kmemleak auto scan thread on boot up"
775 default y
776 depends on DEBUG_KMEMLEAK
777 help
778 Depending on the cpu, kmemleak scan may be cpu intensive and can
779 stall user tasks at times. This option enables/disables automatic
780 kmemleak scan at boot up.
781
782 Say N here to disable kmemleak auto scan thread to stop automatic
783 scanning. Disabling this option disables automatic reporting of
784 memory leaks.
785
786 If unsure, say Y.
787
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DH
788config DEBUG_STACK_USAGE
789 bool "Stack utilization instrumentation"
6c31da34 790 depends on DEBUG_KERNEL && !IA64
0610c8a8
DH
791 help
792 Enables the display of the minimum amount of free stack which each
793 task has ever had available in the sysrq-T and sysrq-P debug output.
794
795 This option will slow down process creation somewhat.
796
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797config SCHED_STACK_END_CHECK
798 bool "Detect stack corruption on calls to schedule()"
799 depends on DEBUG_KERNEL
800 default n
801 help
802 This option checks for a stack overrun on calls to schedule().
803 If the stack end location is found to be over written always panic as
804 the content of the corrupted region can no longer be trusted.
805 This is to ensure no erroneous behaviour occurs which could result in
806 data corruption or a sporadic crash at a later stage once the region
807 is examined. The runtime overhead introduced is minimal.
808
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809config ARCH_HAS_DEBUG_VM_PGTABLE
810 bool
811 help
812 An architecture should select this when it can successfully
813 build and run DEBUG_VM_PGTABLE.
814
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815config DEBUG_VM_IRQSOFF
816 def_bool DEBUG_VM && !PREEMPT_RT
817
0610c8a8
DH
818config DEBUG_VM
819 bool "Debug VM"
820 depends on DEBUG_KERNEL
821 help
822 Enable this to turn on extended checks in the virtual-memory system
68d4b3df 823 that may impact performance.
0610c8a8
DH
824
825 If unsure, say N.
826
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LH
827config DEBUG_VM_MAPLE_TREE
828 bool "Debug VM maple trees"
4f115147 829 depends on DEBUG_VM
54a611b6 830 select DEBUG_MAPLE_TREE
4f115147 831 help
54a611b6 832 Enable VM maple tree debugging information and extra validations.
4f115147
DB
833
834 If unsure, say N.
835
0610c8a8
DH
836config DEBUG_VM_RB
837 bool "Debug VM red-black trees"
838 depends on DEBUG_VM
839 help
a663dad6 840 Enable VM red-black tree debugging information and extra validations.
0610c8a8
DH
841
842 If unsure, say N.
843
95ad9755
KS
844config DEBUG_VM_PGFLAGS
845 bool "Debug page-flags operations"
846 depends on DEBUG_VM
847 help
848 Enables extra validation on page flags operations.
849
850 If unsure, say N.
851
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AK
852config DEBUG_VM_PGTABLE
853 bool "Debug arch page table for semantics compliance"
854 depends on MMU
855 depends on ARCH_HAS_DEBUG_VM_PGTABLE
856 default y if DEBUG_VM
857 help
858 This option provides a debug method which can be used to test
859 architecture page table helper functions on various platforms in
860 verifying if they comply with expected generic MM semantics. This
861 will help architecture code in making sure that any changes or
862 new additions of these helpers still conform to expected
863 semantics of the generic MM. Platforms will have to opt in for
864 this through ARCH_HAS_DEBUG_VM_PGTABLE.
865
866 If unsure, say N.
867
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LA
868config ARCH_HAS_DEBUG_VIRTUAL
869 bool
870
0610c8a8
DH
871config DEBUG_VIRTUAL
872 bool "Debug VM translations"
fa5b6ec9 873 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
0610c8a8
DH
874 help
875 Enable some costly sanity checks in virtual to page code. This can
876 catch mistakes with virt_to_page() and friends.
877
878 If unsure, say N.
879
880config DEBUG_NOMMU_REGIONS
881 bool "Debug the global anon/private NOMMU mapping region tree"
882 depends on DEBUG_KERNEL && !MMU
883 help
884 This option causes the global tree of anonymous and private mapping
885 regions to be regularly checked for invalid topology.
886
887config DEBUG_MEMORY_INIT
888 bool "Debug memory initialisation" if EXPERT
889 default !EXPERT
890 help
891 Enable this for additional checks during memory initialisation.
892 The sanity checks verify aspects of the VM such as the memory model
893 and other information provided by the architecture. Verbose
894 information will be printed at KERN_DEBUG loglevel depending
895 on the mminit_loglevel= command-line option.
896
897 If unsure, say Y
898
899config MEMORY_NOTIFIER_ERROR_INJECT
900 tristate "Memory hotplug notifier error injection module"
50f9481e 901 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
0610c8a8
DH
902 help
903 This option provides the ability to inject artificial errors to
904 memory hotplug notifier chain callbacks. It is controlled through
905 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
906
907 If the notifier call chain should be failed with some events
908 notified, write the error code to "actions/<notifier event>/error".
909
910 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
911
912 # cd /sys/kernel/debug/notifier-error-inject/memory
913 # echo -12 > actions/MEM_GOING_OFFLINE/error
914 # echo offline > /sys/devices/system/memory/memoryXXX/state
915 bash: echo: write error: Cannot allocate memory
916
917 To compile this code as a module, choose M here: the module will
918 be called memory-notifier-error-inject.
919
920 If unsure, say N.
921
922config DEBUG_PER_CPU_MAPS
923 bool "Debug access to per_cpu maps"
924 depends on DEBUG_KERNEL
925 depends on SMP
926 help
927 Say Y to verify that the per_cpu map being accessed has
928 been set up. This adds a fair amount of code to kernel memory
929 and decreases performance.
930
931 Say N if unsure.
932
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TG
933config DEBUG_KMAP_LOCAL
934 bool "Debug kmap_local temporary mappings"
935 depends on DEBUG_KERNEL && KMAP_LOCAL
936 help
937 This option enables additional error checking for the kmap_local
938 infrastructure. Disable for production use.
939
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TG
940config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
941 bool
942
943config DEBUG_KMAP_LOCAL_FORCE_MAP
944 bool "Enforce kmap_local temporary mappings"
945 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
946 select KMAP_LOCAL
947 select DEBUG_KMAP_LOCAL
948 help
949 This option enforces temporary mappings through the kmap_local
950 mechanism for non-highmem pages and on non-highmem systems.
951 Disable this for production systems!
952
0610c8a8
DH
953config DEBUG_HIGHMEM
954 bool "Highmem debugging"
955 depends on DEBUG_KERNEL && HIGHMEM
0e91a0c6 956 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
6e799cb6 957 select DEBUG_KMAP_LOCAL
0610c8a8 958 help
b1357c9f
GU
959 This option enables additional error checking for high memory
960 systems. Disable for production systems.
0610c8a8
DH
961
962config HAVE_DEBUG_STACKOVERFLOW
963 bool
964
965config DEBUG_STACKOVERFLOW
966 bool "Check for stack overflows"
967 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
a7f7f624 968 help
0610c8a8 969 Say Y here if you want to check for overflows of kernel, IRQ
edb0ec07 970 and exception stacks (if your architecture uses them). This
0610c8a8
DH
971 option will show detailed messages if free stack space drops
972 below a certain limit.
973
974 These kinds of bugs usually occur when call-chains in the
975 kernel get too deep, especially when interrupts are
976 involved.
977
978 Use this in cases where you see apparently random memory
979 corruption, especially if it appears in 'struct thread_info'
980
981 If in doubt, say "N".
982
0b24becc 983source "lib/Kconfig.kasan"
0ce20dd8 984source "lib/Kconfig.kfence"
f80be457 985source "lib/Kconfig.kmsan"
0b24becc 986
0610c8a8
DH
987endmenu # "Memory Debugging"
988
a304e1b8
DW
989config DEBUG_SHIRQ
990 bool "Debug shared IRQ handlers"
0244ad00 991 depends on DEBUG_KERNEL
a304e1b8 992 help
0a2fae2a
WS
993 Enable this to generate a spurious interrupt just before a shared
994 interrupt handler is deregistered (generating one when registering
995 is currently disabled). Drivers need to handle this correctly. Some
996 don't and need to be caught.
a304e1b8 997
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CD
998menu "Debug Oops, Lockups and Hangs"
999
1000config PANIC_ON_OOPS
1001 bool "Panic on Oops"
1002 help
1003 Say Y here to enable the kernel to panic when it oopses. This
1004 has the same effect as setting oops=panic on the kernel command
1005 line.
1006
1007 This feature is useful to ensure that the kernel does not do
1008 anything erroneous after an oops which could result in data
1009 corruption or other issues.
1010
1011 Say N if unsure.
1012
1013config PANIC_ON_OOPS_VALUE
1014 int
1015 range 0 1
1016 default 0 if !PANIC_ON_OOPS
1017 default 1 if PANIC_ON_OOPS
1018
1019config PANIC_TIMEOUT
1020 int "panic timeout"
1021 default 0
1022 help
9d5b134f 1023 Set the timeout value (in seconds) until a reboot occurs when
f43a289d
CD
1024 the kernel panics. If n = 0, then we wait forever. A timeout
1025 value n > 0 will wait n seconds before rebooting, while a timeout
1026 value n < 0 will reboot immediately.
92aef8fb 1027
58687acb 1028config LOCKUP_DETECTOR
05a4a952
NP
1029 bool
1030
1031config SOFTLOCKUP_DETECTOR
1032 bool "Detect Soft Lockups"
dea20a3f 1033 depends on DEBUG_KERNEL && !S390
05a4a952 1034 select LOCKUP_DETECTOR
8446f1d3 1035 help
58687acb 1036 Say Y here to enable the kernel to act as a watchdog to detect
05a4a952 1037 soft lockups.
58687acb
DZ
1038
1039 Softlockups are bugs that cause the kernel to loop in kernel
5f329089 1040 mode for more than 20 seconds, without giving other tasks a
58687acb
DZ
1041 chance to run. The current stack trace is displayed upon
1042 detection and the system will stay locked up.
8446f1d3 1043
5f00ae0d
RD
1044config BOOTPARAM_SOFTLOCKUP_PANIC
1045 bool "Panic (Reboot) On Soft Lockups"
1046 depends on SOFTLOCKUP_DETECTOR
1047 help
1048 Say Y here to enable the kernel to panic on "soft lockups",
1049 which are bugs that cause the kernel to loop in kernel
1050 mode for more than 20 seconds (configurable using the watchdog_thresh
1051 sysctl), without giving other tasks a chance to run.
1052
1053 The panic can be used in combination with panic_timeout,
1054 to cause the system to reboot automatically after a
1055 lockup has been detected. This feature is useful for
1056 high-availability systems that have uptime guarantees and
1057 where a lockup must be resolved ASAP.
1058
1059 Say N if unsure.
1060
05a4a952
NP
1061config HARDLOCKUP_DETECTOR_PERF
1062 bool
1063 select SOFTLOCKUP_DETECTOR
1064
7edaeb68
TG
1065#
1066# Enables a timestamp based low pass filter to compensate for perf based
1067# hard lockup detection which runs too fast due to turbo modes.
1068#
1069config HARDLOCKUP_CHECK_TIMESTAMP
1070 bool
1071
05a4a952
NP
1072#
1073# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1074# lockup detector rather than the perf based detector.
1075#
1076config HARDLOCKUP_DETECTOR
1077 bool "Detect Hard Lockups"
1078 depends on DEBUG_KERNEL && !S390
1079 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1080 select LOCKUP_DETECTOR
1081 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
05a4a952
NP
1082 help
1083 Say Y here to enable the kernel to act as a watchdog to detect
1084 hard lockups.
1085
58687acb 1086 Hardlockups are bugs that cause the CPU to loop in kernel mode
5f329089 1087 for more than 10 seconds, without letting other interrupts have a
58687acb
DZ
1088 chance to run. The current stack trace is displayed upon detection
1089 and the system will stay locked up.
8446f1d3 1090
fef2c9bc
DZ
1091config BOOTPARAM_HARDLOCKUP_PANIC
1092 bool "Panic (Reboot) On Hard Lockups"
8f1f66ed 1093 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
1094 help
1095 Say Y here to enable the kernel to panic on "hard lockups",
1096 which are bugs that cause the kernel to loop in kernel
5f329089
FLVC
1097 mode with interrupts disabled for more than 10 seconds (configurable
1098 using the watchdog_thresh sysctl).
fef2c9bc
DZ
1099
1100 Say N if unsure.
1101
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MSB
1102config DETECT_HUNG_TASK
1103 bool "Detect Hung Tasks"
1104 depends on DEBUG_KERNEL
05a4a952 1105 default SOFTLOCKUP_DETECTOR
e162b39a 1106 help
0610c8a8
DH
1107 Say Y here to enable the kernel to detect "hung tasks",
1108 which are bugs that cause the task to be stuck in
96b03ab8 1109 uninterruptible "D" state indefinitely.
1da177e4 1110
0610c8a8
DH
1111 When a hung task is detected, the kernel will print the
1112 current stack trace (which you should report), but the
1113 task will stay in uninterruptible state. If lockdep is
1114 enabled then all held locks will also be reported. This
1115 feature has negligible overhead.
871751e2 1116
0610c8a8
DH
1117config DEFAULT_HUNG_TASK_TIMEOUT
1118 int "Default timeout for hung task detection (in seconds)"
1119 depends on DETECT_HUNG_TASK
1120 default 120
f0630fff 1121 help
0610c8a8
DH
1122 This option controls the default timeout (in seconds) used
1123 to determine when a task has become non-responsive and should
1124 be considered hung.
f0630fff 1125
0610c8a8
DH
1126 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1127 sysctl or by writing a value to
1128 /proc/sys/kernel/hung_task_timeout_secs.
8ff12cfc 1129
0610c8a8
DH
1130 A timeout of 0 disables the check. The default is two minutes.
1131 Keeping the default should be fine in most cases.
b69ec42b 1132
0610c8a8
DH
1133config BOOTPARAM_HUNG_TASK_PANIC
1134 bool "Panic (Reboot) On Hung Tasks"
1135 depends on DETECT_HUNG_TASK
3bba00d7 1136 help
0610c8a8
DH
1137 Say Y here to enable the kernel to panic on "hung tasks",
1138 which are bugs that cause the kernel to leave a task stuck
1139 in uninterruptible "D" state.
3bba00d7 1140
0610c8a8
DH
1141 The panic can be used in combination with panic_timeout,
1142 to cause the system to reboot automatically after a
1143 hung task has been detected. This feature is useful for
1144 high-availability systems that have uptime guarantees and
1145 where a hung tasks must be resolved ASAP.
bf96d1e3 1146
0610c8a8 1147 Say N if unsure.
bf96d1e3 1148
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TH
1149config WQ_WATCHDOG
1150 bool "Detect Workqueue Stalls"
1151 depends on DEBUG_KERNEL
1152 help
1153 Say Y here to enable stall detection on workqueues. If a
1154 worker pool doesn't make forward progress on a pending work
1155 item for over a given amount of time, 30s by default, a
1156 warning message is printed along with dump of workqueue
1157 state. This can be configured through kernel parameter
1158 "workqueue.watchdog_thresh" and its sysfs counterpart.
1159
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KK
1160config TEST_LOCKUP
1161 tristate "Test module to generate lockups"
63646bc9 1162 depends on m
30428ef5
KK
1163 help
1164 This builds the "test_lockup" module that helps to make sure
1165 that watchdogs and lockup detectors are working properly.
1166
1167 Depending on module parameters it could emulate soft or hard
1168 lockup, "hung task", or locking arbitrary lock for a long time.
1169 Also it could generate series of lockups with cooling-down periods.
1170
1171 If unsure, say N.
1172
92aef8fb
DH
1173endmenu # "Debug lockups and hangs"
1174
ebebdd09 1175menu "Scheduler Debugging"
5800dc3c 1176
0610c8a8
DH
1177config SCHED_DEBUG
1178 bool "Collect scheduler debugging info"
1179 depends on DEBUG_KERNEL && PROC_FS
1180 default y
0822ee4a 1181 help
0610c8a8
DH
1182 If you say Y here, the /proc/sched_debug file will be provided
1183 that can help debug the scheduler. The runtime overhead of this
1184 option is minimal.
0822ee4a 1185
f6db8347
NR
1186config SCHED_INFO
1187 bool
1188 default n
1189
0610c8a8
DH
1190config SCHEDSTATS
1191 bool "Collect scheduler statistics"
1192 depends on DEBUG_KERNEL && PROC_FS
f6db8347 1193 select SCHED_INFO
0610c8a8
DH
1194 help
1195 If you say Y here, additional code will be inserted into the
1196 scheduler and related routines to collect statistics about
1197 scheduler behavior and provide them in /proc/schedstat. These
1198 stats may be useful for both tuning and debugging the scheduler
1199 If you aren't debugging the scheduler or trying to tune a specific
1200 application, you can say N to avoid the very slight overhead
1201 this adds.
0822ee4a 1202
ebebdd09 1203endmenu
0d9e2632 1204
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JS
1205config DEBUG_TIMEKEEPING
1206 bool "Enable extra timekeeping sanity checking"
1207 help
1208 This option will enable additional timekeeping sanity checks
1209 which may be helpful when diagnosing issues where timekeeping
1210 problems are suspected.
1211
1212 This may include checks in the timekeeping hotpaths, so this
1213 option may have a (very small) performance impact to some
1214 workloads.
1215
1216 If unsure, say N.
1217
1da177e4
LT
1218config DEBUG_PREEMPT
1219 bool "Debug preemptible kernel"
9f472869 1220 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1da177e4
LT
1221 default y
1222 help
1223 If you say Y here then the kernel will use a debug variant of the
1224 commonly used smp_processor_id() function and will print warnings
1225 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1226 will detect preemption count underflows.
1227
9eade16b
DH
1228menu "Lock Debugging (spinlocks, mutexes, etc...)"
1229
f07cbebb
WL
1230config LOCK_DEBUGGING_SUPPORT
1231 bool
1232 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1233 default y
1234
19193bca
WL
1235config PROVE_LOCKING
1236 bool "Lock debugging: prove locking correctness"
1237 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1238 select LOCKDEP
1239 select DEBUG_SPINLOCK
bb630f9f 1240 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca 1241 select DEBUG_RT_MUTEXES if RT_MUTEXES
c71fd893 1242 select DEBUG_RWSEMS
19193bca
WL
1243 select DEBUG_WW_MUTEX_SLOWPATH
1244 select DEBUG_LOCK_ALLOC
8fd8ad5c 1245 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
19193bca
WL
1246 select TRACE_IRQFLAGS
1247 default n
1248 help
1249 This feature enables the kernel to prove that all locking
1250 that occurs in the kernel runtime is mathematically
1251 correct: that under no circumstance could an arbitrary (and
1252 not yet triggered) combination of observed locking
1253 sequences (on an arbitrary number of CPUs, running an
1254 arbitrary number of tasks and interrupt contexts) cause a
1255 deadlock.
1256
1257 In short, this feature enables the kernel to report locking
1258 related deadlocks before they actually occur.
1259
1260 The proof does not depend on how hard and complex a
1261 deadlock scenario would be to trigger: how many
1262 participant CPUs, tasks and irq-contexts would be needed
1263 for it to trigger. The proof also does not depend on
1264 timing: if a race and a resulting deadlock is possible
1265 theoretically (no matter how unlikely the race scenario
1266 is), it will be proven so and will immediately be
1267 reported by the kernel (once the event is observed that
1268 makes the deadlock theoretically possible).
1269
1270 If a deadlock is impossible (i.e. the locking rules, as
1271 observed by the kernel, are mathematically correct), the
1272 kernel reports nothing.
1273
1274 NOTE: this feature can also be enabled for rwlocks, mutexes
1275 and rwsems - in which case all dependencies between these
1276 different locking variants are observed and mapped too, and
1277 the proof of observed correctness is also maintained for an
1278 arbitrary combination of these separate locking variants.
1279
387b1468 1280 For more details, see Documentation/locking/lockdep-design.rst.
19193bca 1281
de8f5e4f
PZ
1282config PROVE_RAW_LOCK_NESTING
1283 bool "Enable raw_spinlock - spinlock nesting checks"
1284 depends on PROVE_LOCKING
1285 default n
1286 help
1287 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1288 that the lock nesting rules for PREEMPT_RT enabled kernels are
1289 not violated.
1290
1291 NOTE: There are known nesting problems. So if you enable this
1292 option expect lockdep splats until these problems have been fully
1293 addressed which is work in progress. This config switch allows to
1294 identify and analyze these problems. It will be removed and the
9dbbc3b9 1295 check permanently enabled once the main issues have been fixed.
de8f5e4f
PZ
1296
1297 If unsure, select N.
1298
19193bca
WL
1299config LOCK_STAT
1300 bool "Lock usage statistics"
1301 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1302 select LOCKDEP
1303 select DEBUG_SPINLOCK
bb630f9f 1304 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca
WL
1305 select DEBUG_RT_MUTEXES if RT_MUTEXES
1306 select DEBUG_LOCK_ALLOC
1307 default n
1308 help
1309 This feature enables tracking lock contention points
1310
387b1468 1311 For more details, see Documentation/locking/lockstat.rst
19193bca
WL
1312
1313 This also enables lock events required by "perf lock",
1314 subcommand of perf.
1315 If you want to use "perf lock", you also need to turn on
1316 CONFIG_EVENT_TRACING.
1317
1318 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1319 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1320
e7eebaf6
IM
1321config DEBUG_RT_MUTEXES
1322 bool "RT Mutex debugging, deadlock detection"
e7eebaf6
IM
1323 depends on DEBUG_KERNEL && RT_MUTEXES
1324 help
1325 This allows rt mutex semantics violations and rt mutex related
1326 deadlocks (lockups) to be detected and reported automatically.
1327
1da177e4 1328config DEBUG_SPINLOCK
4d9f34ad 1329 bool "Spinlock and rw-lock debugging: basic checks"
1da177e4 1330 depends on DEBUG_KERNEL
e335e3eb 1331 select UNINLINE_SPIN_UNLOCK
1da177e4
LT
1332 help
1333 Say Y here and build SMP to catch missing spinlock initialization
1334 and certain other kinds of spinlock errors commonly made. This is
1335 best used in conjunction with the NMI watchdog so that spinlock
1336 deadlocks are also debuggable.
1337
4d9f34ad
IM
1338config DEBUG_MUTEXES
1339 bool "Mutex debugging: basic checks"
bb630f9f 1340 depends on DEBUG_KERNEL && !PREEMPT_RT
4d9f34ad
IM
1341 help
1342 This feature allows mutex semantics violations to be detected and
1343 reported.
1344
23010027
DV
1345config DEBUG_WW_MUTEX_SLOWPATH
1346 bool "Wait/wound mutex debugging: Slowpath testing"
f07cbebb 1347 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
23010027
DV
1348 select DEBUG_LOCK_ALLOC
1349 select DEBUG_SPINLOCK
bb630f9f
TG
1350 select DEBUG_MUTEXES if !PREEMPT_RT
1351 select DEBUG_RT_MUTEXES if PREEMPT_RT
23010027
DV
1352 help
1353 This feature enables slowpath testing for w/w mutex users by
1354 injecting additional -EDEADLK wound/backoff cases. Together with
1355 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1356 will test all possible w/w mutex interface abuse with the
1357 exception of simply not acquiring all the required locks.
4d692373
RC
1358 Note that this feature can introduce significant overhead, so
1359 it really should not be enabled in a production or distro kernel,
1360 even a debug kernel. If you are a driver writer, enable it. If
1361 you are a distro, do not.
23010027 1362
5149cbac
WL
1363config DEBUG_RWSEMS
1364 bool "RW Semaphore debugging: basic checks"
c71fd893 1365 depends on DEBUG_KERNEL
5149cbac 1366 help
c71fd893
WL
1367 This debugging feature allows mismatched rw semaphore locks
1368 and unlocks to be detected and reported.
5149cbac 1369
4d9f34ad
IM
1370config DEBUG_LOCK_ALLOC
1371 bool "Lock debugging: detect incorrect freeing of live locks"
f07cbebb 1372 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1373 select DEBUG_SPINLOCK
bb630f9f 1374 select DEBUG_MUTEXES if !PREEMPT_RT
f5694788 1375 select DEBUG_RT_MUTEXES if RT_MUTEXES
4d9f34ad
IM
1376 select LOCKDEP
1377 help
1378 This feature will check whether any held lock (spinlock, rwlock,
1379 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1380 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1381 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1382 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1383 held during task exit.
1384
4d9f34ad
IM
1385config LOCKDEP
1386 bool
f07cbebb 1387 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1388 select STACKTRACE
4d9f34ad
IM
1389 select KALLSYMS
1390 select KALLSYMS_ALL
1391
395102db
DJ
1392config LOCKDEP_SMALL
1393 bool
1394
5dc33592
TH
1395config LOCKDEP_BITS
1396 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1397 depends on LOCKDEP && !LOCKDEP_SMALL
1398 range 10 30
1399 default 15
1400 help
1401 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1402
1403config LOCKDEP_CHAINS_BITS
1404 int "Bitsize for MAX_LOCKDEP_CHAINS"
1405 depends on LOCKDEP && !LOCKDEP_SMALL
1406 range 10 30
1407 default 16
1408 help
1409 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1410
1411config LOCKDEP_STACK_TRACE_BITS
1412 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1413 depends on LOCKDEP && !LOCKDEP_SMALL
1414 range 10 30
1415 default 19
1416 help
1417 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1418
1419config LOCKDEP_STACK_TRACE_HASH_BITS
1420 int "Bitsize for STACK_TRACE_HASH_SIZE"
1421 depends on LOCKDEP && !LOCKDEP_SMALL
1422 range 10 30
1423 default 14
1424 help
1425 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1426
1427config LOCKDEP_CIRCULAR_QUEUE_BITS
1428 int "Bitsize for elements in circular_queue struct"
1429 depends on LOCKDEP
1430 range 10 30
1431 default 12
1432 help
1433 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1434
4d9f34ad
IM
1435config DEBUG_LOCKDEP
1436 bool "Lock dependency engine debugging"
517e7aa5 1437 depends on DEBUG_KERNEL && LOCKDEP
997acaf6 1438 select DEBUG_IRQFLAGS
4d9f34ad
IM
1439 help
1440 If you say Y here, the lock dependency engine will do
1441 additional runtime checks to debug itself, at the price
1442 of more runtime overhead.
1443
d902db1e
FW
1444config DEBUG_ATOMIC_SLEEP
1445 bool "Sleep inside atomic section checking"
e8f7c70f 1446 select PREEMPT_COUNT
1da177e4 1447 depends on DEBUG_KERNEL
87a4c375 1448 depends on !ARCH_NO_PREEMPT
1da177e4
LT
1449 help
1450 If you say Y here, various routines which may sleep will become very
d902db1e
FW
1451 noisy if they are called inside atomic sections: when a spinlock is
1452 held, inside an rcu read side critical section, inside preempt disabled
1453 sections, inside an interrupt, etc...
1da177e4 1454
cae2ed9a
IM
1455config DEBUG_LOCKING_API_SELFTESTS
1456 bool "Locking API boot-time self-tests"
1457 depends on DEBUG_KERNEL
1458 help
1459 Say Y here if you want the kernel to run a short self-test during
1460 bootup. The self-test checks whether common types of locking bugs
1461 are detected by debugging mechanisms or not. (if you disable
9dbbc3b9 1462 lock debugging then those bugs won't be detected of course.)
cae2ed9a
IM
1463 The following locking APIs are covered: spinlocks, rwlocks,
1464 mutexes and rwsems.
1465
0af3fe1e
PM
1466config LOCK_TORTURE_TEST
1467 tristate "torture tests for locking"
1468 depends on DEBUG_KERNEL
1469 select TORTURE_TEST
0af3fe1e
PM
1470 help
1471 This option provides a kernel module that runs torture tests
1472 on kernel locking primitives. The kernel module may be built
1473 after the fact on the running kernel to be tested, if desired.
1474
1475 Say Y here if you want kernel locking-primitive torture tests
1476 to be built into the kernel.
1477 Say M if you want these torture tests to build as a module.
1478 Say N if you are unsure.
1479
f2a5fec1
CW
1480config WW_MUTEX_SELFTEST
1481 tristate "Wait/wound mutex selftests"
1482 help
1483 This option provides a kernel module that runs tests on the
1484 on the struct ww_mutex locking API.
1485
1486 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1487 with this test harness.
1488
1489 Say M if you want these self tests to build as a module.
1490 Say N if you are unsure.
1491
e9d338a0
PM
1492config SCF_TORTURE_TEST
1493 tristate "torture tests for smp_call_function*()"
1494 depends on DEBUG_KERNEL
1495 select TORTURE_TEST
1496 help
1497 This option provides a kernel module that runs torture tests
1498 on the smp_call_function() family of primitives. The kernel
1499 module may be built after the fact on the running kernel to
1500 be tested, if desired.
1501
35feb604
PM
1502config CSD_LOCK_WAIT_DEBUG
1503 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1504 depends on DEBUG_KERNEL
1505 depends on 64BIT
1506 default n
1507 help
1508 This option enables debug prints when CPUs are slow to respond
1509 to the smp_call_function*() IPI wrappers. These debug prints
1510 include the IPI handler function currently executing (if any)
1511 and relevant stack traces.
1512
9eade16b 1513endmenu # lock debugging
8637c099 1514
9eade16b 1515config TRACE_IRQFLAGS
ed004953 1516 depends on TRACE_IRQFLAGS_SUPPORT
9eade16b 1517 bool
5ca43f6c 1518 help
9eade16b
DH
1519 Enables hooks to interrupt enabling and disabling for
1520 either tracing or lock debugging.
5ca43f6c 1521
ed004953 1522config TRACE_IRQFLAGS_NMI
1523 def_bool y
1524 depends on TRACE_IRQFLAGS
1525 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1526
997acaf6
MR
1527config DEBUG_IRQFLAGS
1528 bool "Debug IRQ flag manipulation"
1529 help
1530 Enables checks for potentially unsafe enabling or disabling of
1531 interrupts, such as calling raw_local_irq_restore() when interrupts
1532 are enabled.
1533
8637c099 1534config STACKTRACE
0c38e1fe 1535 bool "Stack backtrace support"
8637c099 1536 depends on STACKTRACE_SUPPORT
0c38e1fe
DJ
1537 help
1538 This option causes the kernel to create a /proc/pid/stack for
1539 every process, showing its current stack trace.
1540 It is also used by various kernel debugging features that require
1541 stack trace generation.
5ca43f6c 1542
eecabf56
TT
1543config WARN_ALL_UNSEEDED_RANDOM
1544 bool "Warn for all uses of unseeded randomness"
1545 default n
d06bfd19
JD
1546 help
1547 Some parts of the kernel contain bugs relating to their use of
1548 cryptographically secure random numbers before it's actually possible
1549 to generate those numbers securely. This setting ensures that these
1550 flaws don't go unnoticed, by enabling a message, should this ever
1551 occur. This will allow people with obscure setups to know when things
1552 are going wrong, so that they might contact developers about fixing
1553 it.
1554
eecabf56
TT
1555 Unfortunately, on some models of some architectures getting
1556 a fully seeded CRNG is extremely difficult, and so this can
1557 result in dmesg getting spammed for a surprisingly long
1558 time. This is really bad from a security perspective, and
1559 so architecture maintainers really need to do what they can
1560 to get the CRNG seeded sooner after the system is booted.
4c5d114e 1561 However, since users cannot do anything actionable to
cc1e127b 1562 address this, by default this option is disabled.
eecabf56
TT
1563
1564 Say Y here if you want to receive warnings for all uses of
1565 unseeded randomness. This will be of use primarily for
4c5d114e 1566 those developers interested in improving the security of
eecabf56
TT
1567 Linux kernels running on their architecture (or
1568 subarchitecture).
d06bfd19 1569
1da177e4
LT
1570config DEBUG_KOBJECT
1571 bool "kobject debugging"
1572 depends on DEBUG_KERNEL
1573 help
1574 If you say Y here, some extra kobject debugging messages will be sent
aca52c39 1575 to the syslog.
1da177e4 1576
c817a67e
RK
1577config DEBUG_KOBJECT_RELEASE
1578 bool "kobject release debugging"
2a999aa0 1579 depends on DEBUG_OBJECTS_TIMERS
c817a67e
RK
1580 help
1581 kobjects are reference counted objects. This means that their
1582 last reference count put is not predictable, and the kobject can
b6c69474 1583 live on past the point at which a driver decides to drop its
c817a67e
RK
1584 initial reference to the kobject gained on allocation. An
1585 example of this would be a struct device which has just been
1586 unregistered.
1587
1588 However, some buggy drivers assume that after such an operation,
1589 the memory backing the kobject can be immediately freed. This
1590 goes completely against the principles of a refcounted object.
1591
1592 If you say Y here, the kernel will delay the release of kobjects
1593 on the last reference count to improve the visibility of this
1594 kind of kobject release bug.
1595
9b2a60c4
CM
1596config HAVE_DEBUG_BUGVERBOSE
1597 bool
1598
3be5cbcd 1599menu "Debug kernel data structures"
1da177e4 1600
199a9afc
DJ
1601config DEBUG_LIST
1602 bool "Debug linked list manipulation"
4520bcb2 1603 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
199a9afc
DJ
1604 help
1605 Enable this to turn on extended checks in the linked-list
1606 walking routines.
1607
1608 If unsure, say N.
1609
8e18faea 1610config DEBUG_PLIST
b8cfff68
DS
1611 bool "Debug priority linked list manipulation"
1612 depends on DEBUG_KERNEL
1613 help
1614 Enable this to turn on extended checks in the priority-ordered
1615 linked-list (plist) walking routines. This checks the entire
1616 list multiple times during each manipulation.
1617
1618 If unsure, say N.
1619
d6ec0842
JA
1620config DEBUG_SG
1621 bool "Debug SG table operations"
1622 depends on DEBUG_KERNEL
1623 help
1624 Enable this to turn on checks on scatter-gather tables. This can
1625 help find problems with drivers that do not properly initialize
1626 their sg tables.
1627
1628 If unsure, say N.
1629
1b2439db
AV
1630config DEBUG_NOTIFIERS
1631 bool "Debug notifier call chains"
1632 depends on DEBUG_KERNEL
1633 help
1634 Enable this to turn on sanity checking for notifier call chains.
1635 This is most useful for kernel developers to make sure that
1636 modules properly unregister themselves from notifier chains.
1637 This is a relatively cheap check but if you care about maximum
1638 performance, say N.
1639
3be5cbcd
CD
1640config BUG_ON_DATA_CORRUPTION
1641 bool "Trigger a BUG when data corruption is detected"
1642 select DEBUG_LIST
1643 help
1644 Select this option if the kernel should BUG when it encounters
1645 data corruption in kernel memory structures when they get checked
1646 for validity.
1647
1648 If unsure, say N.
1649
54a611b6
LH
1650config DEBUG_MAPLE_TREE
1651 bool "Debug maple trees"
1652 depends on DEBUG_KERNEL
1653 help
1654 Enable maple tree debugging information and extra validations.
1655
1656 If unsure, say N.
1657
3be5cbcd
CD
1658endmenu
1659
e0e81739
DH
1660config DEBUG_CREDENTIALS
1661 bool "Debug credential management"
1662 depends on DEBUG_KERNEL
1663 help
1664 Enable this to turn on some debug checking for credential
1665 management. The additional code keeps track of the number of
1666 pointers from task_structs to any given cred struct, and checks to
1667 see that this number never exceeds the usage count of the cred
1668 struct.
1669
1670 Furthermore, if SELinux is enabled, this also checks that the
1671 security pointer in the cred struct is never seen to be invalid.
1672
1673 If unsure, say N.
1674
43a0a2a7 1675source "kernel/rcu/Kconfig.debug"
2f03e3ca 1676
f303fccb
TH
1677config DEBUG_WQ_FORCE_RR_CPU
1678 bool "Force round-robin CPU selection for unbound work items"
1679 depends on DEBUG_KERNEL
1680 default n
1681 help
1682 Workqueue used to implicitly guarantee that work items queued
1683 without explicit CPU specified are put on the local CPU. This
1684 guarantee is no longer true and while local CPU is still
1685 preferred work items may be put on foreign CPUs. Kernel
1686 parameter "workqueue.debug_force_rr_cpu" is added to force
1687 round-robin CPU selection to flush out usages which depend on the
1688 now broken guarantee. This config option enables the debug
1689 feature by default. When enabled, memory and cache locality will
1690 be impacted.
1691
757c989b
TG
1692config CPU_HOTPLUG_STATE_CONTROL
1693 bool "Enable CPU hotplug state control"
1694 depends on DEBUG_KERNEL
1695 depends on HOTPLUG_CPU
1696 default n
1697 help
1698 Allows to write steps between "offline" and "online" to the CPUs
1699 sysfs target file so states can be stepped granular. This is a debug
1700 option for now as the hotplug machinery cannot be stopped and
1701 restarted at arbitrary points yet.
1702
1703 Say N if your are unsure.
1704
09a74952
CD
1705config LATENCYTOP
1706 bool "Latency measuring infrastructure"
1707 depends on DEBUG_KERNEL
1708 depends on STACKTRACE_SUPPORT
1709 depends on PROC_FS
7d37cb2c 1710 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
09a74952
CD
1711 select KALLSYMS
1712 select KALLSYMS_ALL
1713 select STACKTRACE
1714 select SCHEDSTATS
09a74952
CD
1715 help
1716 Enable this option if you want to use the LatencyTOP tool
1717 to find out which userspace is blocking on what kernel operations.
1718
1719source "kernel/trace/Kconfig"
1720
1721config PROVIDE_OHCI1394_DMA_INIT
1722 bool "Remote debugging over FireWire early on boot"
1723 depends on PCI && X86
1724 help
1725 If you want to debug problems which hang or crash the kernel early
1726 on boot and the crashing machine has a FireWire port, you can use
1727 this feature to remotely access the memory of the crashed machine
1728 over FireWire. This employs remote DMA as part of the OHCI1394
1729 specification which is now the standard for FireWire controllers.
1730
1731 With remote DMA, you can monitor the printk buffer remotely using
1732 firescope and access all memory below 4GB using fireproxy from gdb.
1733 Even controlling a kernel debugger is possible using remote DMA.
1734
1735 Usage:
1736
1737 If ohci1394_dma=early is used as boot parameter, it will initialize
1738 all OHCI1394 controllers which are found in the PCI config space.
1739
1740 As all changes to the FireWire bus such as enabling and disabling
1741 devices cause a bus reset and thereby disable remote DMA for all
1742 devices, be sure to have the cable plugged and FireWire enabled on
1743 the debugging host before booting the debug target for debugging.
1744
1745 This code (~1k) is freed after boot. By then, the firewire stack
1746 in charge of the OHCI-1394 controllers should be used instead.
1747
a74e2a22 1748 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
09a74952 1749
045f6d79
CD
1750source "samples/Kconfig"
1751
1752config ARCH_HAS_DEVMEM_IS_ALLOWED
1753 bool
1754
1755config STRICT_DEVMEM
1756 bool "Filter access to /dev/mem"
1757 depends on MMU && DEVMEM
527701ed 1758 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
045f6d79
CD
1759 default y if PPC || X86 || ARM64
1760 help
1761 If this option is disabled, you allow userspace (root) access to all
1762 of memory, including kernel and userspace memory. Accidental
1763 access to this is obviously disastrous, but specific access can
1764 be used by people debugging the kernel. Note that with PAT support
1765 enabled, even in this case there are restrictions on /dev/mem
1766 use due to the cache aliasing requirements.
1767
1768 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1769 file only allows userspace access to PCI space and the BIOS code and
1770 data regions. This is sufficient for dosemu and X and all common
1771 users of /dev/mem.
1772
1773 If in doubt, say Y.
1774
1775config IO_STRICT_DEVMEM
1776 bool "Filter I/O access to /dev/mem"
1777 depends on STRICT_DEVMEM
1778 help
1779 If this option is disabled, you allow userspace (root) access to all
1780 io-memory regardless of whether a driver is actively using that
1781 range. Accidental access to this is obviously disastrous, but
1782 specific access can be used by people debugging kernel drivers.
1783
1784 If this option is switched on, the /dev/mem file only allows
1785 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1786 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1787 if the driver using a given range cannot be disabled.
1788
1789 If in doubt, say Y.
1790
1791menu "$(SRCARCH) Debugging"
1792
1793source "arch/$(SRCARCH)/Kconfig.debug"
1794
1795endmenu
1796
1797menu "Kernel Testing and Coverage"
1798
09a74952
CD
1799source "lib/kunit/Kconfig"
1800
8d438288
AM
1801config NOTIFIER_ERROR_INJECTION
1802 tristate "Notifier error injection"
1803 depends on DEBUG_KERNEL
1804 select DEBUG_FS
1805 help
e41e85cc 1806 This option provides the ability to inject artificial errors to
8d438288
AM
1807 specified notifier chain callbacks. It is useful to test the error
1808 handling of notifier call chain failures.
1809
1810 Say N if unsure.
1811
048b9c35
AM
1812config PM_NOTIFIER_ERROR_INJECT
1813 tristate "PM notifier error injection module"
1814 depends on PM && NOTIFIER_ERROR_INJECTION
1815 default m if PM_DEBUG
1816 help
e41e85cc 1817 This option provides the ability to inject artificial errors to
048b9c35
AM
1818 PM notifier chain callbacks. It is controlled through debugfs
1819 interface /sys/kernel/debug/notifier-error-inject/pm
1820
1821 If the notifier call chain should be failed with some events
1822 notified, write the error code to "actions/<notifier event>/error".
1823
1824 Example: Inject PM suspend error (-12 = -ENOMEM)
1825
1826 # cd /sys/kernel/debug/notifier-error-inject/pm/
1827 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1828 # echo mem > /sys/power/state
1829 bash: echo: write error: Cannot allocate memory
1830
1831 To compile this code as a module, choose M here: the module will
1832 be called pm-notifier-error-inject.
1833
1834 If unsure, say N.
1835
d526e85f
BH
1836config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1837 tristate "OF reconfig notifier error injection module"
1838 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dd 1839 help
e41e85cc 1840 This option provides the ability to inject artificial errors to
d526e85f 1841 OF reconfig notifier chain callbacks. It is controlled
08dfb4dd 1842 through debugfs interface under
d526e85f 1843 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
08dfb4dd
AM
1844
1845 If the notifier call chain should be failed with some events
1846 notified, write the error code to "actions/<notifier event>/error".
1847
1848 To compile this code as a module, choose M here: the module will
e12a95f4 1849 be called of-reconfig-notifier-error-inject.
08dfb4dd
AM
1850
1851 If unsure, say N.
1852
02fff96a
NA
1853config NETDEV_NOTIFIER_ERROR_INJECT
1854 tristate "Netdev notifier error injection module"
1855 depends on NET && NOTIFIER_ERROR_INJECTION
1856 help
1857 This option provides the ability to inject artificial errors to
1858 netdevice notifier chain callbacks. It is controlled through debugfs
1859 interface /sys/kernel/debug/notifier-error-inject/netdev
1860
1861 If the notifier call chain should be failed with some events
1862 notified, write the error code to "actions/<notifier event>/error".
1863
1864 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1865
1866 # cd /sys/kernel/debug/notifier-error-inject/netdev
1867 # echo -22 > actions/NETDEV_CHANGEMTU/error
1868 # ip link set eth0 mtu 1024
1869 RTNETLINK answers: Invalid argument
1870
1871 To compile this code as a module, choose M here: the module will
1872 be called netdev-notifier-error-inject.
1873
1874 If unsure, say N.
1875
f1b4bd06
MP
1876config FUNCTION_ERROR_INJECTION
1877 def_bool y
1878 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1879
6ff1cb35 1880config FAULT_INJECTION
1ab8509a
AM
1881 bool "Fault-injection framework"
1882 depends on DEBUG_KERNEL
329409ae
AM
1883 help
1884 Provide fault-injection framework.
1885 For more details, see Documentation/fault-injection/.
6ff1cb35 1886
8a8b6502 1887config FAILSLAB
1ab8509a
AM
1888 bool "Fault-injection capability for kmalloc"
1889 depends on FAULT_INJECTION
773ff60e 1890 depends on SLAB || SLUB
8a8b6502 1891 help
1ab8509a 1892 Provide fault-injection capability for kmalloc.
8a8b6502 1893
933e312e 1894config FAIL_PAGE_ALLOC
29b46fa3 1895 bool "Fault-injection capability for alloc_pages()"
1ab8509a 1896 depends on FAULT_INJECTION
933e312e 1897 help
1ab8509a 1898 Provide fault-injection capability for alloc_pages().
933e312e 1899
2c739ced
AL
1900config FAULT_INJECTION_USERCOPY
1901 bool "Fault injection capability for usercopy functions"
1902 depends on FAULT_INJECTION
1903 help
1904 Provides fault-injection capability to inject failures
1905 in usercopy functions (copy_from_user(), get_user(), ...).
1906
c17bb495 1907config FAIL_MAKE_REQUEST
86327d19 1908 bool "Fault-injection capability for disk IO"
581d4e28 1909 depends on FAULT_INJECTION && BLOCK
c17bb495 1910 help
1ab8509a 1911 Provide fault-injection capability for disk IO.
c17bb495 1912
581d4e28 1913config FAIL_IO_TIMEOUT
f4d01439 1914 bool "Fault-injection capability for faking disk interrupts"
581d4e28
JA
1915 depends on FAULT_INJECTION && BLOCK
1916 help
1917 Provide fault-injection capability on end IO handling. This
1918 will make the block layer "forget" an interrupt as configured,
1919 thus exercising the error handling.
1920
1921 Only works with drivers that use the generic timeout handling,
9dbbc3b9 1922 for others it won't do anything.
581d4e28 1923
ab51fbab
DB
1924config FAIL_FUTEX
1925 bool "Fault-injection capability for futexes"
1926 select DEBUG_FS
1927 depends on FAULT_INJECTION && FUTEX
1928 help
1929 Provide fault-injection capability for futexes.
1930
f1b4bd06
MP
1931config FAULT_INJECTION_DEBUG_FS
1932 bool "Debugfs entries for fault-injection capabilities"
1933 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1934 help
1935 Enable configuration of fault-injection capabilities via debugfs.
1936
4b1a29a7
MH
1937config FAIL_FUNCTION
1938 bool "Fault-injection capability for functions"
1939 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1940 help
1941 Provide function-based fault-injection capability.
1942 This will allow you to override a specific function with a return
1943 with given return value. As a result, function caller will see
1944 an error value and have to handle it. This is useful to test the
1945 error handling in various subsystems.
1946
f1b4bd06
MP
1947config FAIL_MMC_REQUEST
1948 bool "Fault-injection capability for MMC IO"
1949 depends on FAULT_INJECTION_DEBUG_FS && MMC
6ff1cb35 1950 help
f1b4bd06
MP
1951 Provide fault-injection capability for MMC IO.
1952 This will make the mmc core return data errors. This is
1953 useful to test the error handling in the mmc block device
1954 and to test how the mmc host driver handles retries from
1955 the block device.
1df49008 1956
c782af25
CL
1957config FAIL_SUNRPC
1958 bool "Fault-injection capability for SunRPC"
1959 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1960 help
1961 Provide fault-injection capability for SunRPC and
1962 its consumers.
1963
1df49008
AM
1964config FAULT_INJECTION_STACKTRACE_FILTER
1965 bool "stacktrace filter for fault-injection capabilities"
1966 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
6d690dca 1967 depends on !X86_64
1df49008 1968 select STACKTRACE
7d37cb2c 1969 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1df49008
AM
1970 help
1971 Provide stacktrace filter for fault-injection capabilities
267c4025 1972
09a74952
CD
1973config ARCH_HAS_KCOV
1974 bool
cc3fa840 1975 help
09a74952
CD
1976 An architecture should select this when it can successfully
1977 build and run with CONFIG_KCOV. This typically requires
1978 disabling instrumentation for some early boot code.
cc3fa840 1979
09a74952
CD
1980config CC_HAS_SANCOV_TRACE_PC
1981 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
cc3fa840 1982
cc3fa840 1983
09a74952
CD
1984config KCOV
1985 bool "Code coverage for fuzzing"
1986 depends on ARCH_HAS_KCOV
1987 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
22102f45 1988 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
bece04b5 1989 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
09a74952
CD
1990 select DEBUG_FS
1991 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
22102f45 1992 select OBJTOOL if HAVE_NOINSTR_HACK
09a74952
CD
1993 help
1994 KCOV exposes kernel code coverage information in a form suitable
1995 for coverage-guided fuzzing (randomized testing).
cc3fa840 1996
09a74952
CD
1997 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1998 different machines and across reboots. If you need stable PC values,
1999 disable RANDOMIZE_BASE.
cc3fa840 2000
09a74952 2001 For more details, see Documentation/dev-tools/kcov.rst.
cc3fa840 2002
09a74952
CD
2003config KCOV_ENABLE_COMPARISONS
2004 bool "Enable comparison operands collection by KCOV"
2005 depends on KCOV
2006 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2007 help
2008 KCOV also exposes operands of every comparison in the instrumented
2009 code along with operand sizes and PCs of the comparison instructions.
2010 These operands can be used by fuzzing engines to improve the quality
2011 of fuzzing coverage.
cc3fa840 2012
09a74952
CD
2013config KCOV_INSTRUMENT_ALL
2014 bool "Instrument all code by default"
2015 depends on KCOV
2016 default y
2017 help
2018 If you are doing generic system call fuzzing (like e.g. syzkaller),
2019 then you will want to instrument the whole kernel and you should
2020 say y here. If you are doing more targeted fuzzing (like e.g.
2021 filesystem fuzzing with AFL) then you will want to enable coverage
2022 for more specific subsets of files, and should say n here.
84bc809e 2023
5ff3b30a
AK
2024config KCOV_IRQ_AREA_SIZE
2025 hex "Size of interrupt coverage collection area in words"
2026 depends on KCOV
2027 default 0x40000
2028 help
2029 KCOV uses preallocated per-cpu areas to collect coverage from
2030 soft interrupts. This specifies the size of those areas in the
2031 number of unsigned long words.
2032
d3deafaa
VL
2033menuconfig RUNTIME_TESTING_MENU
2034 bool "Runtime Testing"
908009e8 2035 def_bool y
d3deafaa
VL
2036
2037if RUNTIME_TESTING_MENU
881c5149
DH
2038
2039config LKDTM
2040 tristate "Linux Kernel Dump Test Tool Module"
2041 depends on DEBUG_FS
881c5149
DH
2042 help
2043 This module enables testing of the different dumping mechanisms by
2044 inducing system failures at predefined crash points.
2045 If you don't need it: say N
2046 Choose M here to compile this code as a module. The module will be
2047 called lkdtm.
2048
2049 Documentation on how to use the module can be found in
10ffebbe 2050 Documentation/fault-injection/provoke-crashes.rst
881c5149 2051
d3c0ca49
SV
2052config CPUMASK_KUNIT_TEST
2053 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
c41e8866
SV
2054 depends on KUNIT
2055 default KUNIT_ALL_TESTS
2056 help
2057 Enable to turn on cpumask tests, running at boot or module load time.
2058
d3c0ca49
SV
2059 For more information on KUnit and unit tests in general, please refer
2060 to the KUnit documentation in Documentation/dev-tools/kunit/.
2061
c41e8866
SV
2062 If unsure, say N.
2063
881c5149 2064config TEST_LIST_SORT
ebd09577
DL
2065 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2066 depends on KUNIT
2067 default KUNIT_ALL_TESTS
881c5149
DH
2068 help
2069 Enable this to turn on 'list_sort()' function test. This test is
e327fd7c
GU
2070 executed only once during system boot (so affects only boot time),
2071 or at module load time.
881c5149
DH
2072
2073 If unsure, say N.
2074
6e24628d
IR
2075config TEST_MIN_HEAP
2076 tristate "Min heap test"
2077 depends on DEBUG_KERNEL || m
2078 help
2079 Enable this to turn on min heap function tests. This test is
2080 executed only once during system boot (so affects only boot time),
2081 or at module load time.
2082
2083 If unsure, say N.
2084
c5adae95 2085config TEST_SORT
36f33b56
DL
2086 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2087 depends on KUNIT
2088 default KUNIT_ALL_TESTS
c5adae95 2089 help
5c4e6798
GU
2090 This option enables the self-test function of 'sort()' at boot,
2091 or at module load time.
c5adae95
KF
2092
2093 If unsure, say N.
2094
5086ea4b
MR
2095config TEST_DIV64
2096 tristate "64bit/32bit division and modulo test"
2097 depends on DEBUG_KERNEL || m
2098 help
2099 Enable this to turn on 'do_div()' function test. This test is
2100 executed only once during system boot (so affects only boot time),
2101 or at module load time.
2102
2103 If unsure, say N.
2104
881c5149 2105config KPROBES_SANITY_TEST
dcbb2ee2 2106 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
881c5149
DH
2107 depends on DEBUG_KERNEL
2108 depends on KPROBES
e44e81c5 2109 depends on KUNIT
dcbb2ee2 2110 default KUNIT_ALL_TESTS
881c5149
DH
2111 help
2112 This option provides for testing basic kprobes functionality on
5a6cf77f 2113 boot. Samples of kprobe and kretprobe are inserted and
881c5149
DH
2114 verified for functionality.
2115
2116 Say N if you are unsure.
2117
f4616fab
MH
2118config FPROBE_SANITY_TEST
2119 bool "Self test for fprobe"
2120 depends on DEBUG_KERNEL
2121 depends on FPROBE
2122 depends on KUNIT=y
2123 help
2124 This option will enable testing the fprobe when the system boot.
2125 A series of tests are made to verify that the fprobe is functioning
2126 properly.
2127
2128 Say N if you are unsure.
2129
881c5149
DH
2130config BACKTRACE_SELF_TEST
2131 tristate "Self test for the backtrace code"
2132 depends on DEBUG_KERNEL
881c5149
DH
2133 help
2134 This option provides a kernel module that can be used to test
2135 the kernel stack backtrace code. This option is not useful
2136 for distributions or general kernels, but only for kernel
2137 developers working on architecture code.
2138
2139 Note that if you want to also test saved backtraces, you will
2140 have to enable STACKTRACE as well.
2141
2142 Say N if you are unsure.
2143
914a7b50
ED
2144config TEST_REF_TRACKER
2145 tristate "Self test for reference tracker"
2146 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2147 select REF_TRACKER
2148 help
2149 This option provides a kernel module performing tests
2150 using reference tracker infrastructure.
2151
2152 Say N if you are unsure.
2153
910a742d
ML
2154config RBTREE_TEST
2155 tristate "Red-Black tree test"
7c993e11 2156 depends on DEBUG_KERNEL
910a742d
ML
2157 help
2158 A benchmark measuring the performance of the rbtree library.
2159 Also includes rbtree invariant checks.
2160
4b4f3acc
FB
2161config REED_SOLOMON_TEST
2162 tristate "Reed-Solomon library test"
2163 depends on DEBUG_KERNEL || m
2164 select REED_SOLOMON
2165 select REED_SOLOMON_ENC16
2166 select REED_SOLOMON_DEC16
2167 help
2168 This option enables the self-test function of rslib at boot,
2169 or at module load time.
2170
2171 If unsure, say N.
2172
fff3fd8a
ML
2173config INTERVAL_TREE_TEST
2174 tristate "Interval tree test"
0f789b67 2175 depends on DEBUG_KERNEL
a88cc108 2176 select INTERVAL_TREE
fff3fd8a
ML
2177 help
2178 A benchmark measuring the performance of the interval tree library
2179
623fd807
GT
2180config PERCPU_TEST
2181 tristate "Per cpu operations test"
2182 depends on m && DEBUG_KERNEL
2183 help
2184 Enable this option to build test module which validates per-cpu
2185 operations.
2186
2187 If unsure, say N.
2188
881c5149 2189config ATOMIC64_SELFTEST
55ded955 2190 tristate "Perform an atomic64_t self-test"
881c5149 2191 help
55ded955
GU
2192 Enable this option to test the atomic64_t functions at boot or
2193 at module load time.
881c5149
DH
2194
2195 If unsure, say N.
2196
2197config ASYNC_RAID6_TEST
2198 tristate "Self test for hardware accelerated raid6 recovery"
2199 depends on ASYNC_RAID6_RECOV
2200 select ASYNC_MEMCPY
a7f7f624 2201 help
881c5149
DH
2202 This is a one-shot self test that permutes through the
2203 recovery of all the possible two disk failure scenarios for a
2204 N-disk array. Recovery is performed with the asynchronous
2205 raid6 recovery routines, and will optionally use an offload
2206 engine if one is available.
2207
2208 If unsure, say N.
2209
64d1d77a
AS
2210config TEST_HEXDUMP
2211 tristate "Test functions located in the hexdump module at runtime"
2212
b2ff70a0
MC
2213config STRING_SELFTEST
2214 tristate "Test string functions at runtime"
2215
881c5149
DH
2216config TEST_STRING_HELPERS
2217 tristate "Test functions located in the string_helpers module at runtime"
2218
0b0600c8
TH
2219config TEST_STRSCPY
2220 tristate "Test strscpy*() family of functions at runtime"
2221
881c5149
DH
2222config TEST_KSTRTOX
2223 tristate "Test kstrto*() family of functions at runtime"
2224
707cc728
RV
2225config TEST_PRINTF
2226 tristate "Test printf() family of functions at runtime"
2227
50f530e1
RF
2228config TEST_SCANF
2229 tristate "Test scanf() family of functions at runtime"
2230
5fd003f5
DD
2231config TEST_BITMAP
2232 tristate "Test bitmap_*() family of functions at runtime"
5fd003f5
DD
2233 help
2234 Enable this option to test the bitmap functions at boot.
2235
2236 If unsure, say N.
2237
cfaff0e5
AS
2238config TEST_UUID
2239 tristate "Test functions located in the uuid module at runtime"
2240
ad3d6c72
MW
2241config TEST_XARRAY
2242 tristate "Test the XArray code at runtime"
2243
120b1162
LH
2244config TEST_MAPLE_TREE
2245 select DEBUG_MAPLE_TREE
2246 tristate "Test the Maple Tree code at runtime"
2247
7e1e7763 2248config TEST_RHASHTABLE
9d6dbe1b 2249 tristate "Perform selftest on resizable hash table"
7e1e7763
TG
2250 help
2251 Enable this option to test the rhashtable functions at boot.
2252
2253 If unsure, say N.
2254
88168bf3
IB
2255config TEST_SIPHASH
2256 tristate "Perform selftest on siphash functions"
468a9428 2257 help
88168bf3
IB
2258 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2259 functions on boot (or module load).
468a9428
GS
2260
2261 This is intended to help people writing architecture-specific
2262 optimized versions. If unsure, say N.
2263
8ab8ba38
MW
2264config TEST_IDA
2265 tristate "Perform selftest on IDA functions"
2266
44091d29
JP
2267config TEST_PARMAN
2268 tristate "Perform selftest on priority array manager"
44091d29
JP
2269 depends on PARMAN
2270 help
2271 Enable this option to test priority array manager on boot
2272 (or module load).
2273
2274 If unsure, say N.
2275
6aed82de
DL
2276config TEST_IRQ_TIMINGS
2277 bool "IRQ timings selftest"
2278 depends on IRQ_TIMINGS
2279 help
2280 Enable this option to test the irq timings code on boot.
2281
2282 If unsure, say N.
2283
8a6f0b47 2284config TEST_LKM
93e9ef83 2285 tristate "Test module loading with 'hello world' module"
93e9ef83
KC
2286 depends on m
2287 help
2288 This builds the "test_module" module that emits "Hello, world"
2289 on printk when loaded. It is designed to be used for basic
2290 evaluation of the module loading subsystem (for example when
2291 validating module verification). It lacks any extra dependencies,
2292 and will not normally be loaded by the system unless explicitly
2293 requested by name.
2294
2295 If unsure, say N.
2296
c348c163 2297config TEST_BITOPS
6af132f3 2298 tristate "Test module for compilation of bitops operations"
c348c163
JB
2299 depends on m
2300 help
2301 This builds the "test_bitops" module that is much like the
2302 TEST_LKM module except that it does a basic exercise of the
6af132f3
WY
2303 set/clear_bit macros and get_count_order/long to make sure there are
2304 no compiler warnings from C=1 sparse checker or -Wextra
2305 compilations. It has no dependencies and doesn't run or load unless
2306 explicitly requested by name. for example: modprobe test_bitops.
c348c163
JB
2307
2308 If unsure, say N.
2309
3f21a6b7
URS
2310config TEST_VMALLOC
2311 tristate "Test module for stress/performance analysis of vmalloc allocator"
2312 default n
2313 depends on MMU
2314 depends on m
2315 help
2316 This builds the "test_vmalloc" module that should be used for
2317 stress and performance analysis. So, any new change for vmalloc
2318 subsystem can be evaluated from performance and stability point
2319 of view.
2320
2321 If unsure, say N.
2322
3e2a4c18
KC
2323config TEST_USER_COPY
2324 tristate "Test user/kernel boundary protections"
3e2a4c18
KC
2325 depends on m
2326 help
2327 This builds the "test_user_copy" module that runs sanity checks
2328 on the copy_to/from_user infrastructure, making sure basic
2329 user/kernel boundary testing is working. If it fails to load,
2330 a regression has been detected in the user/kernel memory boundary
2331 protections.
2332
2333 If unsure, say N.
2334
64a8946b
AS
2335config TEST_BPF
2336 tristate "Test BPF filter functionality"
98920ba6 2337 depends on m && NET
64a8946b
AS
2338 help
2339 This builds the "test_bpf" module that runs various test vectors
2340 against the BPF interpreter or BPF JIT compiler depending on the
2341 current setting. This is in particular useful for BPF JIT compiler
2342 development, but also to run regression tests against changes in
3c731eba
AS
2343 the interpreter code. It also enables test stubs for eBPF maps and
2344 verifier used by user space verifier testsuite.
64a8946b
AS
2345
2346 If unsure, say N.
2347
509e56b3
MB
2348config TEST_BLACKHOLE_DEV
2349 tristate "Test blackhole netdev functionality"
2350 depends on m && NET
2351 help
2352 This builds the "test_blackhole_dev" module that validates the
2353 data path through this blackhole netdev.
2354
2355 If unsure, say N.
2356
dceeb3e7 2357config FIND_BIT_BENCHMARK
4441fca0 2358 tristate "Test find_bit functions"
4441fca0
YN
2359 help
2360 This builds the "test_find_bit" module that measure find_*_bit()
2361 functions performance.
2362
2363 If unsure, say N.
2364
0a8adf58
KC
2365config TEST_FIRMWARE
2366 tristate "Test firmware loading via userspace interface"
0a8adf58
KC
2367 depends on FW_LOADER
2368 help
2369 This builds the "test_firmware" module that creates a userspace
2370 interface for testing firmware loading. This can be used to
2371 control the triggering of firmware loading without needing an
2372 actual firmware-using device. The contents can be rechecked by
2373 userspace.
2374
2375 If unsure, say N.
2376
9308f2f9
LR
2377config TEST_SYSCTL
2378 tristate "sysctl test driver"
9308f2f9
LR
2379 depends on PROC_SYSCTL
2380 help
2381 This builds the "test_sysctl" module. This driver enables to test the
2382 proc sysctl interfaces available to drivers safely without affecting
2383 production knobs which might alter system functionality.
2384
2385 If unsure, say N.
2386
d2585f51 2387config BITFIELD_KUNIT
dcbb2ee2 2388 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
d2585f51 2389 depends on KUNIT
dcbb2ee2 2390 default KUNIT_ALL_TESTS
d2585f51
VMI
2391 help
2392 Enable this option to test the bitfield functions at boot.
2393
2394 KUnit tests run during boot and output the results to the debug log
2395 in TAP format (http://testanything.org/). Only useful for kernel devs
2396 running the KUnit test harness, and not intended for inclusion into a
2397 production build.
2398
2399 For more information on KUnit and unit tests in general please refer
2400 to the KUnit documentation in Documentation/dev-tools/kunit/.
2401
2402 If unsure, say N.
2403
0acc968f
IB
2404config HASH_KUNIT_TEST
2405 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2406 depends on KUNIT
2407 default KUNIT_ALL_TESTS
2408 help
2409 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2410 integer (<linux/hash.h>) hash functions on boot.
2411
2412 KUnit tests run during boot and output the results to the debug log
2413 in TAP format (https://testanything.org/). Only useful for kernel devs
2414 running the KUnit test harness, and not intended for inclusion into a
2415 production build.
2416
2417 For more information on KUnit and unit tests in general please refer
2418 to the KUnit documentation in Documentation/dev-tools/kunit/.
2419
2420 This is intended to help people writing architecture-specific
2421 optimized versions. If unsure, say N.
2422
5df38ca6 2423config RESOURCE_KUNIT_TEST
dcbb2ee2 2424 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
5df38ca6 2425 depends on KUNIT
dcbb2ee2 2426 default KUNIT_ALL_TESTS
5df38ca6
AS
2427 help
2428 This builds the resource API unit test.
2429 Tests the logic of API provided by resource.c and ioport.h.
2430 For more information on KUnit and unit tests in general please refer
2431 to the KUnit documentation in Documentation/dev-tools/kunit/.
2432
2433 If unsure, say N.
2434
2cb80dbb 2435config SYSCTL_KUNIT_TEST
5f215aab 2436 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2cb80dbb 2437 depends on KUNIT
5f215aab 2438 default KUNIT_ALL_TESTS
2cb80dbb
IZ
2439 help
2440 This builds the proc sysctl unit test, which runs on boot.
2441 Tests the API contract and implementation correctness of sysctl.
2442 For more information on KUnit and unit tests in general please refer
2443 to the KUnit documentation in Documentation/dev-tools/kunit/.
2444
2445 If unsure, say N.
2446
ea2dd7c0 2447config LIST_KUNIT_TEST
5f215aab 2448 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
ea2dd7c0 2449 depends on KUNIT
5f215aab 2450 default KUNIT_ALL_TESTS
ea2dd7c0
DG
2451 help
2452 This builds the linked list KUnit test suite.
2453 It tests that the API and basic functionality of the list_head type
2454 and associated macros.
2455
2456 KUnit tests run during boot and output the results to the debug log
d89775fc 2457 in TAP format (https://testanything.org/). Only useful for kernel devs
ea2dd7c0
DG
2458 running the KUnit test harness, and not intended for inclusion into a
2459 production build.
2460
2461 For more information on KUnit and unit tests in general please refer
2462 to the KUnit documentation in Documentation/dev-tools/kunit/.
2463
2464 If unsure, say N.
2465
33d599f0
MV
2466config LINEAR_RANGES_TEST
2467 tristate "KUnit test for linear_ranges"
2468 depends on KUNIT
2469 select LINEAR_RANGES
2470 help
2471 This builds the linear_ranges unit test, which runs on boot.
2472 Tests the linear_ranges logic correctness.
2473 For more information on KUnit and unit tests in general please refer
7546861a
AS
2474 to the KUnit documentation in Documentation/dev-tools/kunit/.
2475
2476 If unsure, say N.
2477
2478config CMDLINE_KUNIT_TEST
dcbb2ee2 2479 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
7546861a 2480 depends on KUNIT
dcbb2ee2 2481 default KUNIT_ALL_TESTS
7546861a
AS
2482 help
2483 This builds the cmdline API unit test.
2484 Tests the logic of API provided by cmdline.c.
2485 For more information on KUnit and unit tests in general please refer
33d599f0
MV
2486 to the KUnit documentation in Documentation/dev-tools/kunit/.
2487
2488 If unsure, say N.
2489
6d511020 2490config BITS_TEST
dcbb2ee2 2491 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
6d511020 2492 depends on KUNIT
dcbb2ee2 2493 default KUNIT_ALL_TESTS
6d511020
RF
2494 help
2495 This builds the bits unit test.
2496 Tests the logic of macros defined in bits.h.
2497 For more information on KUnit and unit tests in general please refer
2498 to the KUnit documentation in Documentation/dev-tools/kunit/.
2499
2500 If unsure, say N.
2501
1f9f78b1
OG
2502config SLUB_KUNIT_TEST
2503 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2504 depends on SLUB_DEBUG && KUNIT
2505 default KUNIT_ALL_TESTS
2506 help
2507 This builds SLUB allocator unit test.
2508 Tests SLUB cache debugging functionality.
2509 For more information on KUnit and unit tests in general please refer
2510 to the KUnit documentation in Documentation/dev-tools/kunit/.
2511
2512 If unsure, say N.
2513
b6c75c4a
TP
2514config RATIONAL_KUNIT_TEST
2515 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
8ba739ed 2516 depends on KUNIT && RATIONAL
b6c75c4a
TP
2517 default KUNIT_ALL_TESTS
2518 help
2519 This builds the rational math unit test.
2520 For more information on KUnit and unit tests in general please refer
2521 to the KUnit documentation in Documentation/dev-tools/kunit/.
2522
2523 If unsure, say N.
2524
bb95ebbe
KC
2525config MEMCPY_KUNIT_TEST
2526 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2527 depends on KUNIT
2528 default KUNIT_ALL_TESTS
2529 help
2530 Builds unit tests for memcpy(), memmove(), and memset() functions.
2531 For more information on KUnit and unit tests in general please refer
2532 to the KUnit documentation in Documentation/dev-tools/kunit/.
2533
2534 If unsure, say N.
2535
addbeea6
BVA
2536config IS_SIGNED_TYPE_KUNIT_TEST
2537 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2538 depends on KUNIT
2539 default KUNIT_ALL_TESTS
2540 help
2541 Builds unit tests for the is_signed_type() macro.
2542
2543 For more information on KUnit and unit tests in general please refer
2544 to the KUnit documentation in Documentation/dev-tools/kunit/.
2545
2546 If unsure, say N.
2547
617f55e2
KC
2548config OVERFLOW_KUNIT_TEST
2549 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2550 depends on KUNIT
2551 default KUNIT_ALL_TESTS
2552 help
2553 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2554 related functions.
2555
2556 For more information on KUnit and unit tests in general please refer
2557 to the KUnit documentation in Documentation/dev-tools/kunit/.
2558
2559 If unsure, say N.
2560
02788ebc
KC
2561config STACKINIT_KUNIT_TEST
2562 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2563 depends on KUNIT
2564 default KUNIT_ALL_TESTS
2565 help
2566 Test if the kernel is zero-initializing stack variables and
2567 padding. Coverage is controlled by compiler flags,
2568 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2569 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2570 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2571
875bfd52
KC
2572config FORTIFY_KUNIT_TEST
2573 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2574 depends on KUNIT && FORTIFY_SOURCE
2575 default KUNIT_ALL_TESTS
2576 help
2577 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2578 by the str*() and mem*() family of functions. For testing runtime
2579 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2580
724c299c
ME
2581config HW_BREAKPOINT_KUNIT_TEST
2582 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2583 depends on HAVE_HW_BREAKPOINT
2584 depends on KUNIT=y
2585 default KUNIT_ALL_TESTS
2586 help
2587 Tests for hw_breakpoint constraints accounting.
2588
2589 If unsure, say N.
2590
e704f93a
DR
2591config TEST_UDELAY
2592 tristate "udelay test driver"
e704f93a
DR
2593 help
2594 This builds the "udelay_test" module that helps to make sure
2595 that udelay() is working properly.
2596
2597 If unsure, say N.
2598
2bf9e0ab
IM
2599config TEST_STATIC_KEYS
2600 tristate "Test static keys"
579e1acb
JB
2601 depends on m
2602 help
2bf9e0ab 2603 Test the static key interfaces.
579e1acb
JB
2604
2605 If unsure, say N.
2606
683263a5
JC
2607config TEST_DYNAMIC_DEBUG
2608 tristate "Test DYNAMIC_DEBUG"
2609 depends on DYNAMIC_DEBUG
2610 help
2611 This module registers a tracer callback to count enabled
2612 pr_debugs in a 'do_debugging' function, then alters their
2613 enablements, calls the function, and compares counts.
2614
2615 If unsure, say N.
2616
d9c6a72d
LR
2617config TEST_KMOD
2618 tristate "kmod stress tester"
d9c6a72d 2619 depends on m
d9c6a72d 2620 depends on NETDEVICES && NET_CORE && INET # for TUN
ae3d6a32 2621 depends on BLOCK
bbd2e05f 2622 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
d9c6a72d
LR
2623 select TEST_LKM
2624 select XFS_FS
2625 select TUN
2626 select BTRFS_FS
2627 help
2628 Test the kernel's module loading mechanism: kmod. kmod implements
2629 support to load modules using the Linux kernel's usermode helper.
2630 This test provides a series of tests against kmod.
2631
2632 Although technically you can either build test_kmod as a module or
2633 into the kernel we disallow building it into the kernel since
2634 it stress tests request_module() and this will very likely cause
2635 some issues by taking over precious threads available from other
2636 module load requests, ultimately this could be fatal.
2637
2638 To run tests run:
2639
2640 tools/testing/selftests/kmod/kmod.sh --help
2641
2642 If unsure, say N.
2643
e4dace36
FF
2644config TEST_DEBUG_VIRTUAL
2645 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2646 depends on DEBUG_VIRTUAL
2647 help
2648 Test the kernel's ability to detect incorrect calls to
2649 virt_to_phys() done against the non-linear part of the
2650 kernel's virtual address map.
2651
2652 If unsure, say N.
2653
ce76d938
AS
2654config TEST_MEMCAT_P
2655 tristate "Test memcat_p() helper function"
2656 help
2657 Test the memcat_p() helper for correctly merging two
2658 pointer arrays together.
2659
2660 If unsure, say N.
2661
a2818ee4
JL
2662config TEST_LIVEPATCH
2663 tristate "Test livepatching"
2664 default n
bae05437 2665 depends on DYNAMIC_DEBUG
a2818ee4
JL
2666 depends on LIVEPATCH
2667 depends on m
2668 help
2669 Test kernel livepatching features for correctness. The tests will
2670 load test modules that will be livepatched in various scenarios.
2671
2672 To run all the livepatching tests:
2673
2674 make -C tools/testing/selftests TARGETS=livepatch run_tests
2675
2676 Alternatively, individual tests may be invoked:
2677
2678 tools/testing/selftests/livepatch/test-callbacks.sh
2679 tools/testing/selftests/livepatch/test-livepatch.sh
2680 tools/testing/selftests/livepatch/test-shadow-vars.sh
2681
2682 If unsure, say N.
2683
0a020d41
JP
2684config TEST_OBJAGG
2685 tristate "Perform selftest on object aggreration manager"
2686 default n
2687 depends on OBJAGG
2688 help
2689 Enable this option to test object aggregation manager on boot
2690 (or module load).
2691
5015a300
AP
2692config TEST_MEMINIT
2693 tristate "Test heap/page initialization"
2694 help
2695 Test if the kernel is zero-initializing heap and page allocations.
2696 This can be useful to test init_on_alloc and init_on_free features.
2697
2698 If unsure, say N.
2699
b2ef9f5a
RC
2700config TEST_HMM
2701 tristate "Test HMM (Heterogeneous Memory Management)"
2702 depends on TRANSPARENT_HUGEPAGE
2703 depends on DEVICE_PRIVATE
2704 select HMM_MIRROR
2705 select MMU_NOTIFIER
2706 help
2707 This is a pseudo device driver solely for testing HMM.
2708 Say M here if you want to build the HMM test module.
2709 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2710
2711 If unsure, say N.
2712
e320d301
MWO
2713config TEST_FREE_PAGES
2714 tristate "Test freeing pages"
2715 help
2716 Test that a memory leak does not occur due to a race between
2717 freeing a block of pages and a speculative page reference.
2718 Loading this module is safe if your kernel has the bug fixed.
2719 If the bug is not fixed, it will leak gigabytes of memory and
2720 probably OOM your system.
2721
4185b3b9
PA
2722config TEST_FPU
2723 tristate "Test floating point operations in kernel space"
2724 depends on X86 && !KCOV_INSTRUMENT_ALL
2725 help
2726 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2727 which will trigger a sequence of floating point operations. This is used
2728 for self-testing floating point control register setting in
2729 kernel_fpu_begin().
2730
2731 If unsure, say N.
2732
1253b9b8
PM
2733config TEST_CLOCKSOURCE_WATCHDOG
2734 tristate "Test clocksource watchdog in kernel space"
2735 depends on CLOCKSOURCE_WATCHDOG
2736 help
2737 Enable this option to create a kernel module that will trigger
2738 a test of the clocksource watchdog. This module may be loaded
2739 via modprobe or insmod in which case it will run upon being
2740 loaded, or it may be built in, in which case it will run
2741 shortly after boot.
2742
2743 If unsure, say N.
2744
d3deafaa 2745endif # RUNTIME_TESTING_MENU
cc3fa840 2746
dce44566
AK
2747config ARCH_USE_MEMTEST
2748 bool
2749 help
2750 An architecture should select this when it uses early_memtest()
2751 during boot process.
2752
cc3fa840
RD
2753config MEMTEST
2754 bool "Memtest"
dce44566 2755 depends on ARCH_USE_MEMTEST
a7f7f624 2756 help
cc3fa840 2757 This option adds a kernel parameter 'memtest', which allows memtest
dce44566 2758 to be set and executed.
cc3fa840
RD
2759 memtest=0, mean disabled; -- default
2760 memtest=1, mean do 1 test pattern;
2761 ...
2762 memtest=17, mean do 17 test patterns.
2763 If you are unsure how to answer this question, answer N.
2764
21266be9 2765
06ec64b8 2766
af9ca6f9
BB
2767config HYPERV_TESTING
2768 bool "Microsoft Hyper-V driver testing"
2769 default n
2770 depends on HYPERV && DEBUG_FS
2771 help
2772 Select this option to enable Hyper-V vmbus testing.
2773
045f6d79
CD
2774endmenu # "Kernel Testing and Coverage"
2775
2f7ab126
MO
2776menu "Rust hacking"
2777
2778config RUST_DEBUG_ASSERTIONS
2779 bool "Debug assertions"
2780 depends on RUST
2781 help
2782 Enables rustc's `-Cdebug-assertions` codegen option.
2783
2784 This flag lets you turn `cfg(debug_assertions)` conditional
2785 compilation on or off. This can be used to enable extra debugging
2786 code in development but not in production. For example, it controls
2787 the behavior of the standard library's `debug_assert!` macro.
2788
2789 Note that this will apply to all Rust code, including `core`.
2790
2791 If unsure, say N.
2792
2793config RUST_OVERFLOW_CHECKS
2794 bool "Overflow checks"
2795 default y
2796 depends on RUST
2797 help
2798 Enables rustc's `-Coverflow-checks` codegen option.
2799
2800 This flag allows you to control the behavior of runtime integer
2801 overflow. When overflow-checks are enabled, a Rust panic will occur
2802 on overflow.
2803
2804 Note that this will apply to all Rust code, including `core`.
2805
2806 If unsure, say Y.
2807
2808endmenu # "Rust"
2809
75442fb0
MCC
2810source "Documentation/Kconfig"
2811
06ec64b8 2812endmenu # Kernel hacking