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ec8f24b7 1# SPDX-License-Identifier: GPL-2.0-only
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2menu "Kernel hacking"
3
604ff0dc 4menu "printk and dmesg options"
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5
6config PRINTK_TIME
7 bool "Show timing information on printks"
d3b8b6e5 8 depends on PRINTK
1da177e4 9 help
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10 Selecting this option causes time stamps of the printk()
11 messages to be added to the output of the syslog() system
12 call and at the console.
13
14 The timestamp is always recorded internally, and exported
15 to /dev/kmsg. This flag just specifies if the timestamp should
16 be included, not that the timestamp is recorded.
17
18 The behavior is also controlled by the kernel command line
8c27ceff 19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
1da177e4 20
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21config PRINTK_CALLER
22 bool "Show caller information on printks"
23 depends on PRINTK
24 help
25 Selecting this option causes printk() to add a caller "thread id" (if
26 in task context) or a caller "processor id" (if not in task context)
27 to every message.
28
29 This option is intended for environments where multiple threads
30 concurrently call printk() for many times, for it is difficult to
31 interpret without knowing where these lines (or sometimes individual
32 line which was divided into multiple lines due to race) came from.
33
34 Since toggling after boot makes the code racy, currently there is
35 no option to enable/disable at the kernel command line parameter or
36 sysfs interface.
37
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38config STACKTRACE_BUILD_ID
39 bool "Show build ID information in stacktraces"
40 depends on PRINTK
41 help
42 Selecting this option adds build ID information for symbols in
43 stacktraces printed with the printk format '%p[SR]b'.
44
45 This option is intended for distros where debuginfo is not easily
46 accessible but can be downloaded given the build ID of the vmlinux or
47 kernel module where the function is located.
48
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49config CONSOLE_LOGLEVEL_DEFAULT
50 int "Default console loglevel (1-15)"
51 range 1 15
52 default "7"
53 help
54 Default loglevel to determine what will be printed on the console.
55
56 Setting a default here is equivalent to passing in loglevel=<x> in
57 the kernel bootargs. loglevel=<x> continues to override whatever
58 value is specified here as well.
59
50f4d9bd 60 Note: This does not affect the log level of un-prefixed printk()
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61 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
62 option.
63
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64config CONSOLE_LOGLEVEL_QUIET
65 int "quiet console loglevel (1-15)"
66 range 1 15
67 default "4"
68 help
69 loglevel to use when "quiet" is passed on the kernel commandline.
70
71 When "quiet" is passed on the kernel commandline this loglevel
72 will be used as the loglevel. IOW passing "quiet" will be the
73 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
74
42a9dc0b 75config MESSAGE_LOGLEVEL_DEFAULT
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76 int "Default message log level (1-7)"
77 range 1 7
78 default "4"
79 help
80 Default log level for printk statements with no specified priority.
81
82 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83 that are auditing their logs closely may want to set it to a lower
84 priority.
85
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86 Note: This does not affect what message level gets printed on the console
87 by default. To change that, use loglevel=<x> in the kernel bootargs,
88 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
89
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90config BOOT_PRINTK_DELAY
91 bool "Delay each boot printk message by N milliseconds"
92 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
93 help
94 This build option allows you to read kernel boot messages
95 by inserting a short delay after each one. The delay is
96 specified in milliseconds on the kernel command line,
97 using "boot_delay=N".
98
99 It is likely that you would also need to use "lpj=M" to preset
100 the "loops per jiffie" value.
101 See a previous boot log for the "lpj" value to use for your
102 system, and then set "lpj=M" before setting "boot_delay=N".
103 NOTE: Using this option may adversely affect SMP systems.
104 I.e., processors other than the first one may not boot up.
105 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106 what it believes to be lockup conditions.
107
108config DYNAMIC_DEBUG
109 bool "Enable dynamic printk() support"
110 default n
111 depends on PRINTK
239a5791 112 depends on (DEBUG_FS || PROC_FS)
ceabef7d 113 select DYNAMIC_DEBUG_CORE
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114 help
115
116 Compiles debug level messages into the kernel, which would not
117 otherwise be available at runtime. These messages can then be
118 enabled/disabled based on various levels of scope - per source file,
119 function, module, format string, and line number. This mechanism
120 implicitly compiles in all pr_debug() and dev_dbg() calls, which
121 enlarges the kernel text size by about 2%.
122
123 If a source file is compiled with DEBUG flag set, any
124 pr_debug() calls in it are enabled by default, but can be
125 disabled at runtime as below. Note that DEBUG flag is
126 turned on by many CONFIG_*DEBUG* options.
127
128 Usage:
129
130 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
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131 which is contained in the 'debugfs' filesystem or procfs.
132 Thus, the debugfs or procfs filesystem must first be mounted before
133 making use of this feature.
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134 We refer the control file as: <debugfs>/dynamic_debug/control. This
135 file contains a list of the debug statements that can be enabled. The
136 format for each line of the file is:
137
138 filename:lineno [module]function flags format
139
140 filename : source file of the debug statement
141 lineno : line number of the debug statement
142 module : module that contains the debug statement
143 function : function that contains the debug statement
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144 flags : '=p' means the line is turned 'on' for printing
145 format : the format used for the debug statement
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146
147 From a live system:
148
149 nullarbor:~ # cat <debugfs>/dynamic_debug/control
150 # filename:lineno [module]function flags format
151 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154
155 Example usage:
156
157 // enable the message at line 1603 of file svcsock.c
158 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159 <debugfs>/dynamic_debug/control
160
161 // enable all the messages in file svcsock.c
162 nullarbor:~ # echo -n 'file svcsock.c +p' >
163 <debugfs>/dynamic_debug/control
164
165 // enable all the messages in the NFS server module
166 nullarbor:~ # echo -n 'module nfsd +p' >
167 <debugfs>/dynamic_debug/control
168
169 // enable all 12 messages in the function svc_process()
170 nullarbor:~ # echo -n 'func svc_process +p' >
171 <debugfs>/dynamic_debug/control
172
173 // disable all 12 messages in the function svc_process()
174 nullarbor:~ # echo -n 'func svc_process -p' >
175 <debugfs>/dynamic_debug/control
176
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177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
178 information.
604ff0dc 179
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180config DYNAMIC_DEBUG_CORE
181 bool "Enable core function of dynamic debug support"
182 depends on PRINTK
183 depends on (DEBUG_FS || PROC_FS)
184 help
185 Enable core functional support of dynamic debug. It is useful
186 when you want to tie dynamic debug to your kernel modules with
187 DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188 the case of embedded system where the kernel image size is
189 sensitive for people.
190
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191config SYMBOLIC_ERRNAME
192 bool "Support symbolic error names in printf"
193 default y if PRINTK
194 help
195 If you say Y here, the kernel's printf implementation will
196 be able to print symbolic error names such as ENOSPC instead
197 of the number 28. It makes the kernel image slightly larger
198 (about 3KB), but can make the kernel logs easier to read.
199
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200config DEBUG_BUGVERBOSE
201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
203 default y
204 help
205 Say Y here to make BUG() panics output the file name and line number
206 of the BUG call as well as the EIP and oops trace. This aids
207 debugging but costs about 70-100K of memory.
208
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209endmenu # "printk and dmesg options"
210
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211config DEBUG_KERNEL
212 bool "Kernel debugging"
213 help
214 Say Y here if you are developing drivers or trying to debug and
215 identify kernel problems.
216
217config DEBUG_MISC
218 bool "Miscellaneous debug code"
219 default DEBUG_KERNEL
220 depends on DEBUG_KERNEL
221 help
222 Say Y here if you need to enable miscellaneous debug code that should
223 be under a more specific debug option but isn't.
224
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225menu "Compile-time checks and compiler options"
226
227config DEBUG_INFO
f9b3cd24 228 bool
6dfc0665 229 help
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230 A kernel debug info option other than "None" has been selected
231 in the "Debug information" choice below, indicating that debug
232 information will be generated for build targets.
233
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234# Clang generates .uleb128 with label differences for DWARF v5, a feature that
235# older binutils ports do not support when utilizing RISC-V style linker
236# relaxation: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
237config AS_HAS_NON_CONST_ULEB128
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238 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
239
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240choice
241 prompt "Debug information"
242 depends on DEBUG_KERNEL
243 help
244 Selecting something other than "None" results in a kernel image
245 that will include debugging info resulting in a larger kernel image.
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246 This adds debug symbols to the kernel and modules (gcc -g), and
247 is needed if you intend to use kernel crashdump or binary object
248 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
6dfc0665 249
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250 Choose which version of DWARF debug info to emit. If unsure,
251 select "Toolchain default".
252
253config DEBUG_INFO_NONE
254 bool "Disable debug information"
255 help
256 Do not build the kernel with debugging information, which will
257 result in a faster and smaller build.
258
259config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
260 bool "Rely on the toolchain's implicit default DWARF version"
261 select DEBUG_INFO
a4426641 262 depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
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263 help
264 The implicit default version of DWARF debug info produced by a
265 toolchain changes over time.
266
267 This can break consumers of the debug info that haven't upgraded to
268 support newer revisions, and prevent testing newer versions, but
269 those should be less common scenarios.
270
271config DEBUG_INFO_DWARF4
272 bool "Generate DWARF Version 4 debuginfo"
273 select DEBUG_INFO
4f001a21 274 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
f9b3cd24 275 help
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276 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
277 if using clang without clang's integrated assembler, and gdb 7.0+.
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278
279 If you have consumers of DWARF debug info that are not ready for
280 newer revisions of DWARF, you may wish to choose this or have your
281 config select this.
282
283config DEBUG_INFO_DWARF5
284 bool "Generate DWARF Version 5 debuginfo"
285 select DEBUG_INFO
ae84ff9a 286 depends on !ARCH_HAS_BROKEN_DWARF5
a4426641 287 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
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288 help
289 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
290 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
291 draft features until 7.0), and gdb 8.0+.
292
293 Changes to the structure of debug info in Version 5 allow for around
294 15-18% savings in resulting image and debug info section sizes as
295 compared to DWARF Version 4. DWARF Version 5 standardizes previous
296 extensions such as accelerators for symbol indexing and the format
297 for fission (.dwo/.dwp) files. Users may not want to select this
298 config if they rely on tooling that has not yet been updated to
299 support DWARF Version 5.
300
301endchoice # "Debug information"
6dfc0665 302
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303if DEBUG_INFO
304
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305config DEBUG_INFO_REDUCED
306 bool "Reduce debugging information"
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307 help
308 If you say Y here gcc is instructed to generate less debugging
309 information for structure types. This means that tools that
310 need full debugging information (like kgdb or systemtap) won't
311 be happy. But if you merely need debugging information to
312 resolve line numbers there is no loss. Advantage is that
313 build directory object sizes shrink dramatically over a full
314 DEBUG_INFO build and compile times are reduced too.
315 Only works with newer gcc versions.
316
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317choice
318 prompt "Compressed Debug information"
319 help
320 Compress the resulting debug info. Results in smaller debug info sections,
321 but requires that consumers are able to decompress the results.
322
323 If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
324
325config DEBUG_INFO_COMPRESSED_NONE
326 bool "Don't compress debug information"
327 help
328 Don't compress debug info sections.
329
330config DEBUG_INFO_COMPRESSED_ZLIB
331 bool "Compress debugging information with zlib"
10e68b02 332 depends on $(cc-option,-gz=zlib)
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333 depends on $(ld-option,--compress-debug-sections=zlib)
334 help
335 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
336 5.0+, binutils 2.26+, and zlib.
337
338 Users of dpkg-deb via scripts/package/builddeb may find an increase in
339 size of their debug .deb packages with this config set, due to the
340 debug info being compressed with zlib, then the object files being
341 recompressed with a different compression scheme. But this is still
342 preferable to setting $KDEB_COMPRESS to "none" which would be even
343 larger.
344
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345config DEBUG_INFO_COMPRESSED_ZSTD
346 bool "Compress debugging information with zstd"
347 depends on $(cc-option,-gz=zstd)
348 depends on $(ld-option,--compress-debug-sections=zstd)
349 help
350 Compress the debug information using zstd. This may provide better
351 compression than zlib, for about the same time costs, but requires newer
352 toolchain support. Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
353 zstd.
354
355endchoice # "Compressed Debug information"
356
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357config DEBUG_INFO_SPLIT
358 bool "Produce split debuginfo in .dwo files"
9d937444 359 depends on $(cc-option,-gsplit-dwarf)
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360 # RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC
361 # prior to 12.x:
362 # https://github.com/llvm/llvm-project/issues/56642
363 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090
364 depends on !RISCV || GCC_VERSION >= 120000
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365 help
366 Generate debug info into separate .dwo files. This significantly
367 reduces the build directory size for builds with DEBUG_INFO,
368 because it stores the information only once on disk in .dwo
369 files instead of multiple times in object files and executables.
370 In addition the debug information is also compressed.
371
372 Requires recent gcc (4.7+) and recent gdb/binutils.
373 Any tool that packages or reads debug information would need
374 to know about the .dwo files and include them.
375 Incompatible with older versions of ccache.
376
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377config DEBUG_INFO_BTF
378 bool "Generate BTF typeinfo"
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379 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
380 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
d9847eb8 381 depends on BPF_SYSCALL
52deda95 382 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
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383 # pahole uses elfutils, which does not have support for Hexagon relocations
384 depends on !HEXAGON
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385 help
386 Generate deduplicated BTF type information from DWARF debug info.
387 Turning this on expects presence of pahole tool, which will convert
388 DWARF type info into equivalent deduplicated BTF type info.
389
5f9ae91f 390config PAHOLE_HAS_SPLIT_BTF
6323c813 391 def_bool PAHOLE_VERSION >= 119
5f9ae91f 392
7472d5a6 393config PAHOLE_HAS_BTF_TAG
6323c813 394 def_bool PAHOLE_VERSION >= 123
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395 depends on CC_IS_CLANG
396 help
397 Decide whether pahole emits btf_tag attributes (btf_type_tag and
398 btf_decl_tag) or not. Currently only clang compiler implements
399 these attributes, so make the config depend on CC_IS_CLANG.
5f9ae91f 400
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401config PAHOLE_HAS_LANG_EXCLUDE
402 def_bool PAHOLE_VERSION >= 124
403 help
404 Support for the --lang_exclude flag which makes pahole exclude
405 compilation units from the supplied language. Used in Kbuild to
406 omit Rust CUs which are not supported in version 1.24 of pahole,
407 otherwise it would emit malformed kernel and module binaries when
408 using DEBUG_INFO_BTF_MODULES.
409
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410config DEBUG_INFO_BTF_MODULES
411 def_bool y
412 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
413 help
414 Generate compact split BTF type information for kernel modules.
415
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416config MODULE_ALLOW_BTF_MISMATCH
417 bool "Allow loading modules with non-matching BTF type info"
418 depends on DEBUG_INFO_BTF_MODULES
419 help
420 For modules whose split BTF does not match vmlinux, load without
421 BTF rather than refusing to load. The default behavior with
422 module BTF enabled is to reject modules with such mismatches;
423 this option will still load module BTF where possible but ignore
424 it when a mismatch is found.
425
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426config GDB_SCRIPTS
427 bool "Provide GDB scripts for kernel debugging"
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428 help
429 This creates the required links to GDB helper scripts in the
430 build directory. If you load vmlinux into gdb, the helper
431 scripts will be automatically imported by gdb as well, and
432 additional functions are available to analyze a Linux kernel
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433 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
434 for further details.
3ee7b3fa 435
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436endif # DEBUG_INFO
437
35bb5b1e 438config FRAME_WARN
a83e4ca2 439 int "Warn for stack frames larger than"
35bb5b1e 440 range 0 8192
ac66998d 441 default 0 if KMSAN
0e07f663 442 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
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443 default 2048 if PARISC
444 default 1536 if (!64BIT && XTENSA)
152fe65f 445 default 1280 if KASAN && !64BIT
8d192bec 446 default 1024 if !64BIT
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447 default 2048 if 64BIT
448 help
921757bc 449 Tell the compiler to warn at build time for stack frames larger than this.
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450 Setting this too low will cause a lot of warnings.
451 Setting it to 0 disables the warning.
35bb5b1e 452
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453config STRIP_ASM_SYMS
454 bool "Strip assembler-generated symbols during link"
455 default n
456 help
457 Strip internal assembler-generated symbols during a link (symbols
458 that look like '.Lxxx') so they don't pollute the output of
459 get_wchan() and suchlike.
460
1873e870 461config READABLE_ASM
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462 bool "Generate readable assembler code"
463 depends on DEBUG_KERNEL
7d73c3e9 464 depends on CC_IS_GCC
bf4735a4 465 help
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466 Disable some compiler optimizations that tend to generate human unreadable
467 assembler output. This may make the kernel slightly slower, but it helps
468 to keep kernel developers who have to stare a lot at assembler listings
469 sane.
bf4735a4 470
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471config HEADERS_INSTALL
472 bool "Install uapi headers to usr/include"
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473 depends on !UML
474 help
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475 This option will install uapi headers (headers exported to user-space)
476 into the usr/include directory for use during the kernel build.
477 This is unneeded for building the kernel itself, but needed for some
478 user-space program samples. It is also needed by some features such
479 as uapi header sanity checks.
480
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481config DEBUG_SECTION_MISMATCH
482 bool "Enable full Section mismatch analysis"
7d73c3e9 483 depends on CC_IS_GCC
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484 help
485 The section mismatch analysis checks if there are illegal
486 references from one section to another section.
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487 During linktime or runtime, some sections are dropped;
488 any use of code/data previously in these sections would
91341d4b 489 most likely result in an oops.
e809ab01 490 In the code, functions and variables are annotated with
0db0628d 491 __init,, etc. (see the full list in include/linux/init.h),
d6fbfa4f 492 which results in the code/data being placed in specific sections.
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493 The section mismatch analysis is always performed after a full
494 kernel build, and enabling this option causes the following
b7dca6dd 495 additional step to occur:
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496 - Add the option -fno-inline-functions-called-once to gcc commands.
497 When inlining a function annotated with __init in a non-init
498 function, we would lose the section information and thus
91341d4b 499 the analysis would not catch the illegal reference.
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500 This option tells gcc to inline less (but it does result in
501 a larger kernel).
91341d4b 502
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503config SECTION_MISMATCH_WARN_ONLY
504 bool "Make section mismatch errors non-fatal"
505 default y
506 help
507 If you say N here, the build process will fail if there are any
508 section mismatch, instead of just throwing warnings.
509
510 If unsure, say Y.
511
cf536e18 512config DEBUG_FORCE_FUNCTION_ALIGN_64B
1bf18da6 513 bool "Force all function address 64B aligned"
3ed8513c 514 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390)
d49a0626 515 select FUNCTION_ALIGNMENT_64B
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516 help
517 There are cases that a commit from one domain changes the function
518 address alignment of other domains, and cause magic performance
519 bump (regression or improvement). Enable this option will help to
520 verify if the bump is caused by function alignment changes, while
521 it will slightly increase the kernel size and affect icache usage.
522
523 It is mainly for debug and performance tuning use.
524
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525#
526# Select this config option from the architecture Kconfig, if it
527# is preferred to always offer frame pointers as a config
528# option on the architecture (regardless of KERNEL_DEBUG):
529#
530config ARCH_WANT_FRAME_POINTERS
531 bool
f346f4b3 532
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533config FRAME_POINTER
534 bool "Compile the kernel with frame pointers"
a687a533 535 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
6dfc0665 536 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
a304e1b8 537 help
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538 If you say Y here the resulting kernel image will be slightly
539 larger and slower, but it gives very useful debugging information
540 in case of kernel bugs. (precise oopses/stacktraces/warnings)
a304e1b8 541
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542config OBJTOOL
543 bool
544
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545config STACK_VALIDATION
546 bool "Compile-time stack metadata validation"
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547 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
548 select OBJTOOL
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549 default n
550 help
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551 Validate frame pointer rules at compile-time. This helps ensure that
552 runtime stack traces are more reliable.
ee9f8fce 553
b9ab5ebb 554 For more information, see
d6a21f2d 555 tools/objtool/Documentation/objtool.txt.
b9ab5ebb 556
0f620cef 557config NOINSTR_VALIDATION
6804c1af 558 bool
489e355b 559 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
03f16cd0 560 select OBJTOOL
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561 default y
562
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563config VMLINUX_MAP
564 bool "Generate vmlinux.map file when linking"
565 depends on EXPERT
566 help
567 Selecting this option will pass "-Map=vmlinux.map" to ld
568 when linking vmlinux. That file can be useful for verifying
569 and debugging magic section games, and for seeing which
570 pieces of code get eliminated with
571 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
572
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573config DEBUG_FORCE_WEAK_PER_CPU
574 bool "Force weak per-cpu definitions"
575 depends on DEBUG_KERNEL
8446f1d3 576 help
6dfc0665
DH
577 s390 and alpha require percpu variables in modules to be
578 defined weak to work around addressing range issue which
579 puts the following two restrictions on percpu variable
580 definitions.
8446f1d3 581
6dfc0665
DH
582 1. percpu symbols must be unique whether static or not
583 2. percpu variables can't be defined inside a function
8446f1d3 584
6dfc0665
DH
585 To ensure that generic code follows the above rules, this
586 option forces all percpu variables to be defined as weak.
5f329089 587
6dfc0665 588endmenu # "Compiler options"
8446f1d3 589
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CD
590menu "Generic Kernel Debugging Instruments"
591
6dfc0665
DH
592config MAGIC_SYSRQ
593 bool "Magic SysRq key"
594 depends on !UML
595 help
596 If you say Y here, you will have some control over the system even
597 if the system crashes for example during kernel debugging (e.g., you
598 will be able to flush the buffer cache to disk, reboot the system
599 immediately or dump some status information). This is accomplished
600 by pressing various keys while holding SysRq (Alt+PrintScreen). It
601 also works on a serial console (on PC hardware at least), if you
602 send a BREAK and then within 5 seconds a command keypress. The
f8998c22
HH
603 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
604 Don't say Y unless you really know what this hack does.
8446f1d3 605
8eaede49
BH
606config MAGIC_SYSRQ_DEFAULT_ENABLE
607 hex "Enable magic SysRq key functions by default"
608 depends on MAGIC_SYSRQ
609 default 0x1
610 help
611 Specifies which SysRq key functions are enabled by default.
612 This may be set to 1 or 0 to enable or disable them all, or
f8998c22 613 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
8eaede49 614
732dbf3a
FF
615config MAGIC_SYSRQ_SERIAL
616 bool "Enable magic SysRq key over serial"
617 depends on MAGIC_SYSRQ
618 default y
619 help
620 Many embedded boards have a disconnected TTL level serial which can
621 generate some garbage that can lead to spurious false sysrq detects.
622 This option allows you to decide whether you want to enable the
623 magic SysRq key.
624
68af4317
DS
625config MAGIC_SYSRQ_SERIAL_SEQUENCE
626 string "Char sequence that enables magic SysRq over serial"
627 depends on MAGIC_SYSRQ_SERIAL
628 default ""
629 help
630 Specifies a sequence of characters that can follow BREAK to enable
631 SysRq on a serial console.
632
d3394b3d
DS
633 If unsure, leave an empty string and the option will not be enabled.
634
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CD
635config DEBUG_FS
636 bool "Debug Filesystem"
637 help
638 debugfs is a virtual file system that kernel developers use to put
639 debugging files into. Enable this option to be able to read and
640 write to these files.
641
642 For detailed documentation on the debugfs API, see
643 Documentation/filesystems/.
644
645 If unsure, say N.
646
a24c6f7b
PE
647choice
648 prompt "Debugfs default access"
649 depends on DEBUG_FS
650 default DEBUG_FS_ALLOW_ALL
651 help
652 This selects the default access restrictions for debugfs.
653 It can be overridden with kernel command line option
654 debugfs=[on,no-mount,off]. The restrictions apply for API access
655 and filesystem registration.
656
657config DEBUG_FS_ALLOW_ALL
658 bool "Access normal"
659 help
660 No restrictions apply. Both API and filesystem registration
661 is on. This is the normal default operation.
662
663config DEBUG_FS_DISALLOW_MOUNT
664 bool "Do not register debugfs as filesystem"
665 help
666 The API is open but filesystem is not loaded. Clients can still do
667 their work and read with debug tools that do not need
668 debugfs filesystem.
669
670config DEBUG_FS_ALLOW_NONE
671 bool "No access"
672 help
673 Access is off. Clients get -PERM when trying to create nodes in
674 debugfs tree and debugfs is not registered as a filesystem.
675 Client can then back-off or continue without debugfs access.
676
677endchoice
678
6210b640 679source "lib/Kconfig.kgdb"
6210b640 680source "lib/Kconfig.ubsan"
2645d432 681source "lib/Kconfig.kcsan"
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CD
682
683endmenu
684
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685menu "Networking Debugging"
686
687source "net/Kconfig.debug"
688
689endmenu # "Networking Debugging"
c66d7a27 690
0610c8a8 691menu "Memory Debugging"
fef2c9bc 692
8636a1f9 693source "mm/Kconfig.debug"
fef2c9bc 694
0610c8a8
DH
695config DEBUG_OBJECTS
696 bool "Debug object operations"
697 depends on DEBUG_KERNEL
9c44bc03 698 help
0610c8a8
DH
699 If you say Y here, additional code will be inserted into the
700 kernel to track the life time of various objects and validate
701 the operations on those objects.
9c44bc03 702
0610c8a8
DH
703config DEBUG_OBJECTS_SELFTEST
704 bool "Debug objects selftest"
705 depends on DEBUG_OBJECTS
706 help
707 This enables the selftest of the object debug code.
9c44bc03 708
0610c8a8
DH
709config DEBUG_OBJECTS_FREE
710 bool "Debug objects in freed memory"
711 depends on DEBUG_OBJECTS
712 help
713 This enables checks whether a k/v free operation frees an area
714 which contains an object which has not been deactivated
715 properly. This can make kmalloc/kfree-intensive workloads
716 much slower.
3ac7fe5a 717
c6f3a97f
TG
718config DEBUG_OBJECTS_TIMERS
719 bool "Debug timer objects"
720 depends on DEBUG_OBJECTS
721 help
722 If you say Y here, additional code will be inserted into the
723 timer routines to track the life time of timer objects and
724 validate the timer operations.
725
dc186ad7
TG
726config DEBUG_OBJECTS_WORK
727 bool "Debug work objects"
728 depends on DEBUG_OBJECTS
729 help
730 If you say Y here, additional code will be inserted into the
731 work queue routines to track the life time of work objects and
732 validate the work operations.
733
551d55a9
MD
734config DEBUG_OBJECTS_RCU_HEAD
735 bool "Debug RCU callbacks objects"
fc2ecf7e 736 depends on DEBUG_OBJECTS
551d55a9
MD
737 help
738 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
739
e2852ae8
TH
740config DEBUG_OBJECTS_PERCPU_COUNTER
741 bool "Debug percpu counter objects"
742 depends on DEBUG_OBJECTS
743 help
744 If you say Y here, additional code will be inserted into the
745 percpu counter routines to track the life time of percpu counter
746 objects and validate the percpu counter operations.
747
3ae70205
IM
748config DEBUG_OBJECTS_ENABLE_DEFAULT
749 int "debug_objects bootup default value (0-1)"
68d4b3df
KK
750 range 0 1
751 default "1"
752 depends on DEBUG_OBJECTS
753 help
754 Debug objects boot parameter default value
3ae70205 755
5035ebc6 756config SHRINKER_DEBUG
5035ebc6
RG
757 bool "Enable shrinker debugging support"
758 depends on DEBUG_FS
759 help
760 Say Y to enable the shrinker debugfs interface which provides
761 visibility into the kernel memory shrinkers subsystem.
762 Disable it to avoid an extra memory footprint.
763
0610c8a8
DH
764config DEBUG_STACK_USAGE
765 bool "Stack utilization instrumentation"
cf8e8658 766 depends on DEBUG_KERNEL
0610c8a8
DH
767 help
768 Enables the display of the minimum amount of free stack which each
769 task has ever had available in the sysrq-T and sysrq-P debug output.
bc09d1de
UKK
770 Also emits a message to dmesg when a process exits if that process
771 used more stack space than previously exiting processes.
0610c8a8
DH
772
773 This option will slow down process creation somewhat.
774
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CD
775config SCHED_STACK_END_CHECK
776 bool "Detect stack corruption on calls to schedule()"
777 depends on DEBUG_KERNEL
778 default n
779 help
780 This option checks for a stack overrun on calls to schedule().
781 If the stack end location is found to be over written always panic as
782 the content of the corrupted region can no longer be trusted.
783 This is to ensure no erroneous behaviour occurs which could result in
784 data corruption or a sporadic crash at a later stage once the region
785 is examined. The runtime overhead introduced is minimal.
786
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AK
787config ARCH_HAS_DEBUG_VM_PGTABLE
788 bool
789 help
790 An architecture should select this when it can successfully
791 build and run DEBUG_VM_PGTABLE.
792
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TG
793config DEBUG_VM_IRQSOFF
794 def_bool DEBUG_VM && !PREEMPT_RT
795
0610c8a8
DH
796config DEBUG_VM
797 bool "Debug VM"
798 depends on DEBUG_KERNEL
799 help
800 Enable this to turn on extended checks in the virtual-memory system
68d4b3df 801 that may impact performance.
0610c8a8
DH
802
803 If unsure, say N.
804
2655421a
NP
805config DEBUG_VM_SHOOT_LAZIES
806 bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
807 depends on DEBUG_VM
808 depends on MMU_LAZY_TLB_SHOOTDOWN
809 help
810 Enable additional IPIs that ensure lazy tlb mm references are removed
811 before the mm is freed.
812
813 If unsure, say N.
814
54a611b6
LH
815config DEBUG_VM_MAPLE_TREE
816 bool "Debug VM maple trees"
4f115147 817 depends on DEBUG_VM
54a611b6 818 select DEBUG_MAPLE_TREE
4f115147 819 help
54a611b6 820 Enable VM maple tree debugging information and extra validations.
4f115147
DB
821
822 If unsure, say N.
823
0610c8a8
DH
824config DEBUG_VM_RB
825 bool "Debug VM red-black trees"
826 depends on DEBUG_VM
827 help
a663dad6 828 Enable VM red-black tree debugging information and extra validations.
0610c8a8
DH
829
830 If unsure, say N.
831
95ad9755
KS
832config DEBUG_VM_PGFLAGS
833 bool "Debug page-flags operations"
834 depends on DEBUG_VM
835 help
836 Enables extra validation on page flags operations.
837
838 If unsure, say N.
839
399145f9
AK
840config DEBUG_VM_PGTABLE
841 bool "Debug arch page table for semantics compliance"
842 depends on MMU
843 depends on ARCH_HAS_DEBUG_VM_PGTABLE
844 default y if DEBUG_VM
845 help
846 This option provides a debug method which can be used to test
847 architecture page table helper functions on various platforms in
848 verifying if they comply with expected generic MM semantics. This
849 will help architecture code in making sure that any changes or
850 new additions of these helpers still conform to expected
851 semantics of the generic MM. Platforms will have to opt in for
852 this through ARCH_HAS_DEBUG_VM_PGTABLE.
853
854 If unsure, say N.
855
fa5b6ec9
LA
856config ARCH_HAS_DEBUG_VIRTUAL
857 bool
858
0610c8a8
DH
859config DEBUG_VIRTUAL
860 bool "Debug VM translations"
fa5b6ec9 861 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
0610c8a8
DH
862 help
863 Enable some costly sanity checks in virtual to page code. This can
864 catch mistakes with virt_to_page() and friends.
865
866 If unsure, say N.
867
868config DEBUG_NOMMU_REGIONS
869 bool "Debug the global anon/private NOMMU mapping region tree"
870 depends on DEBUG_KERNEL && !MMU
871 help
872 This option causes the global tree of anonymous and private mapping
873 regions to be regularly checked for invalid topology.
874
875config DEBUG_MEMORY_INIT
876 bool "Debug memory initialisation" if EXPERT
877 default !EXPERT
878 help
879 Enable this for additional checks during memory initialisation.
880 The sanity checks verify aspects of the VM such as the memory model
881 and other information provided by the architecture. Verbose
882 information will be printed at KERN_DEBUG loglevel depending
883 on the mminit_loglevel= command-line option.
884
885 If unsure, say Y
886
887config MEMORY_NOTIFIER_ERROR_INJECT
888 tristate "Memory hotplug notifier error injection module"
50f9481e 889 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
0610c8a8
DH
890 help
891 This option provides the ability to inject artificial errors to
892 memory hotplug notifier chain callbacks. It is controlled through
893 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
894
895 If the notifier call chain should be failed with some events
896 notified, write the error code to "actions/<notifier event>/error".
897
898 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
899
900 # cd /sys/kernel/debug/notifier-error-inject/memory
901 # echo -12 > actions/MEM_GOING_OFFLINE/error
902 # echo offline > /sys/devices/system/memory/memoryXXX/state
903 bash: echo: write error: Cannot allocate memory
904
905 To compile this code as a module, choose M here: the module will
906 be called memory-notifier-error-inject.
907
908 If unsure, say N.
909
910config DEBUG_PER_CPU_MAPS
911 bool "Debug access to per_cpu maps"
912 depends on DEBUG_KERNEL
913 depends on SMP
914 help
915 Say Y to verify that the per_cpu map being accessed has
916 been set up. This adds a fair amount of code to kernel memory
917 and decreases performance.
918
919 Say N if unsure.
920
6e799cb6
TG
921config DEBUG_KMAP_LOCAL
922 bool "Debug kmap_local temporary mappings"
923 depends on DEBUG_KERNEL && KMAP_LOCAL
924 help
925 This option enables additional error checking for the kmap_local
926 infrastructure. Disable for production use.
927
0e91a0c6
TG
928config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
929 bool
930
931config DEBUG_KMAP_LOCAL_FORCE_MAP
932 bool "Enforce kmap_local temporary mappings"
933 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
934 select KMAP_LOCAL
935 select DEBUG_KMAP_LOCAL
936 help
937 This option enforces temporary mappings through the kmap_local
938 mechanism for non-highmem pages and on non-highmem systems.
939 Disable this for production systems!
940
0610c8a8
DH
941config DEBUG_HIGHMEM
942 bool "Highmem debugging"
943 depends on DEBUG_KERNEL && HIGHMEM
0e91a0c6 944 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
6e799cb6 945 select DEBUG_KMAP_LOCAL
0610c8a8 946 help
b1357c9f
GU
947 This option enables additional error checking for high memory
948 systems. Disable for production systems.
0610c8a8
DH
949
950config HAVE_DEBUG_STACKOVERFLOW
951 bool
952
953config DEBUG_STACKOVERFLOW
954 bool "Check for stack overflows"
955 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
a7f7f624 956 help
0610c8a8 957 Say Y here if you want to check for overflows of kernel, IRQ
edb0ec07 958 and exception stacks (if your architecture uses them). This
0610c8a8
DH
959 option will show detailed messages if free stack space drops
960 below a certain limit.
961
962 These kinds of bugs usually occur when call-chains in the
963 kernel get too deep, especially when interrupts are
964 involved.
965
966 Use this in cases where you see apparently random memory
967 corruption, especially if it appears in 'struct thread_info'
968
969 If in doubt, say "N".
970
0b24becc 971source "lib/Kconfig.kasan"
0ce20dd8 972source "lib/Kconfig.kfence"
f80be457 973source "lib/Kconfig.kmsan"
0b24becc 974
0610c8a8
DH
975endmenu # "Memory Debugging"
976
a304e1b8
DW
977config DEBUG_SHIRQ
978 bool "Debug shared IRQ handlers"
0244ad00 979 depends on DEBUG_KERNEL
a304e1b8 980 help
0a2fae2a
WS
981 Enable this to generate a spurious interrupt just before a shared
982 interrupt handler is deregistered (generating one when registering
983 is currently disabled). Drivers need to handle this correctly. Some
984 don't and need to be caught.
a304e1b8 985
f43a289d
CD
986menu "Debug Oops, Lockups and Hangs"
987
988config PANIC_ON_OOPS
989 bool "Panic on Oops"
990 help
991 Say Y here to enable the kernel to panic when it oopses. This
992 has the same effect as setting oops=panic on the kernel command
993 line.
994
995 This feature is useful to ensure that the kernel does not do
996 anything erroneous after an oops which could result in data
997 corruption or other issues.
998
999 Say N if unsure.
1000
1001config PANIC_ON_OOPS_VALUE
1002 int
1003 range 0 1
1004 default 0 if !PANIC_ON_OOPS
1005 default 1 if PANIC_ON_OOPS
1006
1007config PANIC_TIMEOUT
1008 int "panic timeout"
1009 default 0
1010 help
9d5b134f 1011 Set the timeout value (in seconds) until a reboot occurs when
f43a289d
CD
1012 the kernel panics. If n = 0, then we wait forever. A timeout
1013 value n > 0 will wait n seconds before rebooting, while a timeout
1014 value n < 0 will reboot immediately.
92aef8fb 1015
58687acb 1016config LOCKUP_DETECTOR
05a4a952
NP
1017 bool
1018
1019config SOFTLOCKUP_DETECTOR
1020 bool "Detect Soft Lockups"
dea20a3f 1021 depends on DEBUG_KERNEL && !S390
05a4a952 1022 select LOCKUP_DETECTOR
8446f1d3 1023 help
58687acb 1024 Say Y here to enable the kernel to act as a watchdog to detect
05a4a952 1025 soft lockups.
58687acb
DZ
1026
1027 Softlockups are bugs that cause the kernel to loop in kernel
5f329089 1028 mode for more than 20 seconds, without giving other tasks a
58687acb
DZ
1029 chance to run. The current stack trace is displayed upon
1030 detection and the system will stay locked up.
8446f1d3 1031
5f00ae0d
RD
1032config BOOTPARAM_SOFTLOCKUP_PANIC
1033 bool "Panic (Reboot) On Soft Lockups"
1034 depends on SOFTLOCKUP_DETECTOR
1035 help
1036 Say Y here to enable the kernel to panic on "soft lockups",
1037 which are bugs that cause the kernel to loop in kernel
1038 mode for more than 20 seconds (configurable using the watchdog_thresh
1039 sysctl), without giving other tasks a chance to run.
1040
1041 The panic can be used in combination with panic_timeout,
1042 to cause the system to reboot automatically after a
1043 lockup has been detected. This feature is useful for
1044 high-availability systems that have uptime guarantees and
1045 where a lockup must be resolved ASAP.
1046
1047 Say N if unsure.
1048
1356d0b9 1049config HAVE_HARDLOCKUP_DETECTOR_BUDDY
05a4a952 1050 bool
1356d0b9
PM
1051 depends on SMP
1052 default y
05a4a952 1053
7edaeb68 1054#
1356d0b9
PM
1055# Global switch whether to build a hardlockup detector at all. It is available
1056# only when the architecture supports at least one implementation. There are
1057# two exceptions. The hardlockup detector is never enabled on:
7edaeb68 1058#
1356d0b9 1059# s390: it reported many false positives there
05a4a952 1060#
1356d0b9
PM
1061# sparc64: has a custom implementation which is not using the common
1062# hardlockup command line options and sysctl interface.
05a4a952
NP
1063#
1064config HARDLOCKUP_DETECTOR
1065 bool "Detect Hard Lockups"
47f4cb43 1066 depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
a5fcc236 1067 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
1356d0b9
PM
1068 imply HARDLOCKUP_DETECTOR_PERF
1069 imply HARDLOCKUP_DETECTOR_BUDDY
7ca8fe94 1070 imply HARDLOCKUP_DETECTOR_ARCH
05a4a952 1071 select LOCKUP_DETECTOR
4917a25f 1072
05a4a952
NP
1073 help
1074 Say Y here to enable the kernel to act as a watchdog to detect
1075 hard lockups.
1076
58687acb 1077 Hardlockups are bugs that cause the CPU to loop in kernel mode
5f329089 1078 for more than 10 seconds, without letting other interrupts have a
58687acb
DZ
1079 chance to run. The current stack trace is displayed upon detection
1080 and the system will stay locked up.
8446f1d3 1081
1356d0b9
PM
1082#
1083# Note that arch-specific variants are always preferred.
1084#
4917a25f
PM
1085config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1086 bool "Prefer the buddy CPU hardlockup detector"
1356d0b9
PM
1087 depends on HARDLOCKUP_DETECTOR
1088 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
a8992d8a 1089 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
4917a25f
PM
1090 help
1091 Say Y here to prefer the buddy hardlockup detector over the perf one.
1092
1093 With the buddy detector, each CPU uses its softlockup hrtimer
1094 to check that the next CPU is processing hrtimer interrupts by
1095 verifying that a counter is increasing.
1096
1097 This hardlockup detector is useful on systems that don't have
1098 an arch-specific hardlockup detector or if resources needed
1099 for the hardlockup detector are better used for other things.
05a4a952 1100
1f423c90
DA
1101config HARDLOCKUP_DETECTOR_PERF
1102 bool
1356d0b9
PM
1103 depends on HARDLOCKUP_DETECTOR
1104 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
a5fcc236 1105 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1f423c90
DA
1106 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1107
1108config HARDLOCKUP_DETECTOR_BUDDY
1109 bool
1356d0b9
PM
1110 depends on HARDLOCKUP_DETECTOR
1111 depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1112 depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
a5fcc236 1113 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1f423c90
DA
1114 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1115
7ca8fe94
PM
1116config HARDLOCKUP_DETECTOR_ARCH
1117 bool
1118 depends on HARDLOCKUP_DETECTOR
1119 depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1120 help
1121 The arch-specific implementation of the hardlockup detector will
1122 be used.
1123
1356d0b9 1124#
4917a25f
PM
1125# Both the "perf" and "buddy" hardlockup detectors count hrtimer
1126# interrupts. This config enables functions managing this common code.
1356d0b9 1127#
4917a25f
PM
1128config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1129 bool
1130 select SOFTLOCKUP_DETECTOR
1131
7edaeb68
TG
1132#
1133# Enables a timestamp based low pass filter to compensate for perf based
1134# hard lockup detection which runs too fast due to turbo modes.
1135#
1136config HARDLOCKUP_CHECK_TIMESTAMP
1137 bool
1138
fef2c9bc
DZ
1139config BOOTPARAM_HARDLOCKUP_PANIC
1140 bool "Panic (Reboot) On Hard Lockups"
8f1f66ed 1141 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
1142 help
1143 Say Y here to enable the kernel to panic on "hard lockups",
1144 which are bugs that cause the kernel to loop in kernel
5f329089
FLVC
1145 mode with interrupts disabled for more than 10 seconds (configurable
1146 using the watchdog_thresh sysctl).
fef2c9bc
DZ
1147
1148 Say N if unsure.
1149
e162b39a
MSB
1150config DETECT_HUNG_TASK
1151 bool "Detect Hung Tasks"
1152 depends on DEBUG_KERNEL
05a4a952 1153 default SOFTLOCKUP_DETECTOR
e162b39a 1154 help
0610c8a8
DH
1155 Say Y here to enable the kernel to detect "hung tasks",
1156 which are bugs that cause the task to be stuck in
96b03ab8 1157 uninterruptible "D" state indefinitely.
1da177e4 1158
0610c8a8
DH
1159 When a hung task is detected, the kernel will print the
1160 current stack trace (which you should report), but the
1161 task will stay in uninterruptible state. If lockdep is
1162 enabled then all held locks will also be reported. This
1163 feature has negligible overhead.
871751e2 1164
0610c8a8
DH
1165config DEFAULT_HUNG_TASK_TIMEOUT
1166 int "Default timeout for hung task detection (in seconds)"
1167 depends on DETECT_HUNG_TASK
1168 default 120
f0630fff 1169 help
0610c8a8
DH
1170 This option controls the default timeout (in seconds) used
1171 to determine when a task has become non-responsive and should
1172 be considered hung.
f0630fff 1173
0610c8a8
DH
1174 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1175 sysctl or by writing a value to
1176 /proc/sys/kernel/hung_task_timeout_secs.
8ff12cfc 1177
0610c8a8
DH
1178 A timeout of 0 disables the check. The default is two minutes.
1179 Keeping the default should be fine in most cases.
b69ec42b 1180
0610c8a8
DH
1181config BOOTPARAM_HUNG_TASK_PANIC
1182 bool "Panic (Reboot) On Hung Tasks"
1183 depends on DETECT_HUNG_TASK
3bba00d7 1184 help
0610c8a8
DH
1185 Say Y here to enable the kernel to panic on "hung tasks",
1186 which are bugs that cause the kernel to leave a task stuck
1187 in uninterruptible "D" state.
3bba00d7 1188
0610c8a8
DH
1189 The panic can be used in combination with panic_timeout,
1190 to cause the system to reboot automatically after a
1191 hung task has been detected. This feature is useful for
1192 high-availability systems that have uptime guarantees and
1193 where a hung tasks must be resolved ASAP.
bf96d1e3 1194
0610c8a8 1195 Say N if unsure.
bf96d1e3 1196
82607adc
TH
1197config WQ_WATCHDOG
1198 bool "Detect Workqueue Stalls"
1199 depends on DEBUG_KERNEL
1200 help
1201 Say Y here to enable stall detection on workqueues. If a
1202 worker pool doesn't make forward progress on a pending work
1203 item for over a given amount of time, 30s by default, a
1204 warning message is printed along with dump of workqueue
1205 state. This can be configured through kernel parameter
1206 "workqueue.watchdog_thresh" and its sysfs counterpart.
1207
63638450
TH
1208config WQ_CPU_INTENSIVE_REPORT
1209 bool "Report per-cpu work items which hog CPU for too long"
1210 depends on DEBUG_KERNEL
1211 help
1212 Say Y here to enable reporting of concurrency-managed per-cpu work
1213 items that hog CPUs for longer than
b2ec116a 1214 workqueue.cpu_intensive_thresh_us. Workqueue automatically
63638450
TH
1215 detects and excludes them from concurrency management to prevent
1216 them from stalling other per-cpu work items. Occassional
1217 triggering may not necessarily indicate a problem. Repeated
1218 triggering likely indicates that the work item should be switched
1219 to use an unbound workqueue.
1220
30428ef5
KK
1221config TEST_LOCKUP
1222 tristate "Test module to generate lockups"
63646bc9 1223 depends on m
30428ef5
KK
1224 help
1225 This builds the "test_lockup" module that helps to make sure
1226 that watchdogs and lockup detectors are working properly.
1227
1228 Depending on module parameters it could emulate soft or hard
1229 lockup, "hung task", or locking arbitrary lock for a long time.
1230 Also it could generate series of lockups with cooling-down periods.
1231
1232 If unsure, say N.
1233
92aef8fb
DH
1234endmenu # "Debug lockups and hangs"
1235
ebebdd09 1236menu "Scheduler Debugging"
5800dc3c 1237
0610c8a8
DH
1238config SCHED_DEBUG
1239 bool "Collect scheduler debugging info"
35260cf5 1240 depends on DEBUG_KERNEL && DEBUG_FS
0610c8a8 1241 default y
0822ee4a 1242 help
1e90e35b 1243 If you say Y here, the /sys/kernel/debug/sched file will be provided
0610c8a8
DH
1244 that can help debug the scheduler. The runtime overhead of this
1245 option is minimal.
0822ee4a 1246
f6db8347
NR
1247config SCHED_INFO
1248 bool
1249 default n
1250
0610c8a8
DH
1251config SCHEDSTATS
1252 bool "Collect scheduler statistics"
1253 depends on DEBUG_KERNEL && PROC_FS
f6db8347 1254 select SCHED_INFO
0610c8a8
DH
1255 help
1256 If you say Y here, additional code will be inserted into the
1257 scheduler and related routines to collect statistics about
1258 scheduler behavior and provide them in /proc/schedstat. These
1259 stats may be useful for both tuning and debugging the scheduler
1260 If you aren't debugging the scheduler or trying to tune a specific
1261 application, you can say N to avoid the very slight overhead
1262 this adds.
0822ee4a 1263
ebebdd09 1264endmenu
0d9e2632 1265
3c17ad19
JS
1266config DEBUG_TIMEKEEPING
1267 bool "Enable extra timekeeping sanity checking"
1268 help
1269 This option will enable additional timekeeping sanity checks
1270 which may be helpful when diagnosing issues where timekeeping
1271 problems are suspected.
1272
1273 This may include checks in the timekeeping hotpaths, so this
1274 option may have a (very small) performance impact to some
1275 workloads.
1276
1277 If unsure, say N.
1278
1da177e4
LT
1279config DEBUG_PREEMPT
1280 bool "Debug preemptible kernel"
9f472869 1281 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1da177e4
LT
1282 help
1283 If you say Y here then the kernel will use a debug variant of the
1284 commonly used smp_processor_id() function and will print warnings
1285 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1286 will detect preemption count underflows.
1287
cc600391
HY
1288 This option has potential to introduce high runtime overhead,
1289 depending on workload as it triggers debugging routines for each
1290 this_cpu operation. It should only be used for debugging purposes.
1291
9eade16b
DH
1292menu "Lock Debugging (spinlocks, mutexes, etc...)"
1293
f07cbebb
WL
1294config LOCK_DEBUGGING_SUPPORT
1295 bool
1296 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1297 default y
1298
19193bca
WL
1299config PROVE_LOCKING
1300 bool "Lock debugging: prove locking correctness"
1301 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1302 select LOCKDEP
1303 select DEBUG_SPINLOCK
bb630f9f 1304 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca 1305 select DEBUG_RT_MUTEXES if RT_MUTEXES
f22f7132 1306 select DEBUG_RWSEMS if !PREEMPT_RT
19193bca
WL
1307 select DEBUG_WW_MUTEX_SLOWPATH
1308 select DEBUG_LOCK_ALLOC
8fd8ad5c 1309 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
19193bca
WL
1310 select TRACE_IRQFLAGS
1311 default n
1312 help
1313 This feature enables the kernel to prove that all locking
1314 that occurs in the kernel runtime is mathematically
1315 correct: that under no circumstance could an arbitrary (and
1316 not yet triggered) combination of observed locking
1317 sequences (on an arbitrary number of CPUs, running an
1318 arbitrary number of tasks and interrupt contexts) cause a
1319 deadlock.
1320
1321 In short, this feature enables the kernel to report locking
1322 related deadlocks before they actually occur.
1323
1324 The proof does not depend on how hard and complex a
1325 deadlock scenario would be to trigger: how many
1326 participant CPUs, tasks and irq-contexts would be needed
1327 for it to trigger. The proof also does not depend on
1328 timing: if a race and a resulting deadlock is possible
1329 theoretically (no matter how unlikely the race scenario
1330 is), it will be proven so and will immediately be
1331 reported by the kernel (once the event is observed that
1332 makes the deadlock theoretically possible).
1333
1334 If a deadlock is impossible (i.e. the locking rules, as
1335 observed by the kernel, are mathematically correct), the
1336 kernel reports nothing.
1337
1338 NOTE: this feature can also be enabled for rwlocks, mutexes
1339 and rwsems - in which case all dependencies between these
1340 different locking variants are observed and mapped too, and
1341 the proof of observed correctness is also maintained for an
1342 arbitrary combination of these separate locking variants.
1343
387b1468 1344 For more details, see Documentation/locking/lockdep-design.rst.
19193bca 1345
de8f5e4f
PZ
1346config PROVE_RAW_LOCK_NESTING
1347 bool "Enable raw_spinlock - spinlock nesting checks"
1348 depends on PROVE_LOCKING
1349 default n
1350 help
1351 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1352 that the lock nesting rules for PREEMPT_RT enabled kernels are
1353 not violated.
1354
1355 NOTE: There are known nesting problems. So if you enable this
1356 option expect lockdep splats until these problems have been fully
1357 addressed which is work in progress. This config switch allows to
1358 identify and analyze these problems. It will be removed and the
9dbbc3b9 1359 check permanently enabled once the main issues have been fixed.
de8f5e4f
PZ
1360
1361 If unsure, select N.
1362
19193bca
WL
1363config LOCK_STAT
1364 bool "Lock usage statistics"
1365 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1366 select LOCKDEP
1367 select DEBUG_SPINLOCK
bb630f9f 1368 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca
WL
1369 select DEBUG_RT_MUTEXES if RT_MUTEXES
1370 select DEBUG_LOCK_ALLOC
1371 default n
1372 help
1373 This feature enables tracking lock contention points
1374
387b1468 1375 For more details, see Documentation/locking/lockstat.rst
19193bca
WL
1376
1377 This also enables lock events required by "perf lock",
1378 subcommand of perf.
1379 If you want to use "perf lock", you also need to turn on
1380 CONFIG_EVENT_TRACING.
1381
1382 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1383 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1384
e7eebaf6
IM
1385config DEBUG_RT_MUTEXES
1386 bool "RT Mutex debugging, deadlock detection"
e7eebaf6
IM
1387 depends on DEBUG_KERNEL && RT_MUTEXES
1388 help
1389 This allows rt mutex semantics violations and rt mutex related
1390 deadlocks (lockups) to be detected and reported automatically.
1391
1da177e4 1392config DEBUG_SPINLOCK
4d9f34ad 1393 bool "Spinlock and rw-lock debugging: basic checks"
1da177e4 1394 depends on DEBUG_KERNEL
e335e3eb 1395 select UNINLINE_SPIN_UNLOCK
1da177e4
LT
1396 help
1397 Say Y here and build SMP to catch missing spinlock initialization
1398 and certain other kinds of spinlock errors commonly made. This is
1399 best used in conjunction with the NMI watchdog so that spinlock
1400 deadlocks are also debuggable.
1401
4d9f34ad
IM
1402config DEBUG_MUTEXES
1403 bool "Mutex debugging: basic checks"
bb630f9f 1404 depends on DEBUG_KERNEL && !PREEMPT_RT
4d9f34ad
IM
1405 help
1406 This feature allows mutex semantics violations to be detected and
1407 reported.
1408
23010027
DV
1409config DEBUG_WW_MUTEX_SLOWPATH
1410 bool "Wait/wound mutex debugging: Slowpath testing"
f07cbebb 1411 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
23010027
DV
1412 select DEBUG_LOCK_ALLOC
1413 select DEBUG_SPINLOCK
bb630f9f
TG
1414 select DEBUG_MUTEXES if !PREEMPT_RT
1415 select DEBUG_RT_MUTEXES if PREEMPT_RT
23010027
DV
1416 help
1417 This feature enables slowpath testing for w/w mutex users by
1418 injecting additional -EDEADLK wound/backoff cases. Together with
1419 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1420 will test all possible w/w mutex interface abuse with the
1421 exception of simply not acquiring all the required locks.
4d692373
RC
1422 Note that this feature can introduce significant overhead, so
1423 it really should not be enabled in a production or distro kernel,
1424 even a debug kernel. If you are a driver writer, enable it. If
1425 you are a distro, do not.
23010027 1426
5149cbac
WL
1427config DEBUG_RWSEMS
1428 bool "RW Semaphore debugging: basic checks"
f22f7132 1429 depends on DEBUG_KERNEL && !PREEMPT_RT
5149cbac 1430 help
c71fd893
WL
1431 This debugging feature allows mismatched rw semaphore locks
1432 and unlocks to be detected and reported.
5149cbac 1433
4d9f34ad
IM
1434config DEBUG_LOCK_ALLOC
1435 bool "Lock debugging: detect incorrect freeing of live locks"
f07cbebb 1436 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1437 select DEBUG_SPINLOCK
bb630f9f 1438 select DEBUG_MUTEXES if !PREEMPT_RT
f5694788 1439 select DEBUG_RT_MUTEXES if RT_MUTEXES
4d9f34ad
IM
1440 select LOCKDEP
1441 help
1442 This feature will check whether any held lock (spinlock, rwlock,
1443 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1444 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1445 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1446 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1447 held during task exit.
1448
4d9f34ad
IM
1449config LOCKDEP
1450 bool
f07cbebb 1451 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1452 select STACKTRACE
4d9f34ad
IM
1453 select KALLSYMS
1454 select KALLSYMS_ALL
1455
395102db
DJ
1456config LOCKDEP_SMALL
1457 bool
1458
5dc33592
TH
1459config LOCKDEP_BITS
1460 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1461 depends on LOCKDEP && !LOCKDEP_SMALL
1462 range 10 30
1463 default 15
1464 help
1465 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1466
1467config LOCKDEP_CHAINS_BITS
1468 int "Bitsize for MAX_LOCKDEP_CHAINS"
1469 depends on LOCKDEP && !LOCKDEP_SMALL
1470 range 10 30
1471 default 16
1472 help
1473 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1474
1475config LOCKDEP_STACK_TRACE_BITS
1476 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1477 depends on LOCKDEP && !LOCKDEP_SMALL
1478 range 10 30
1479 default 19
1480 help
1481 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1482
1483config LOCKDEP_STACK_TRACE_HASH_BITS
1484 int "Bitsize for STACK_TRACE_HASH_SIZE"
1485 depends on LOCKDEP && !LOCKDEP_SMALL
1486 range 10 30
1487 default 14
1488 help
f478b998 1489 Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
5dc33592
TH
1490
1491config LOCKDEP_CIRCULAR_QUEUE_BITS
1492 int "Bitsize for elements in circular_queue struct"
1493 depends on LOCKDEP
1494 range 10 30
1495 default 12
1496 help
1497 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1498
4d9f34ad
IM
1499config DEBUG_LOCKDEP
1500 bool "Lock dependency engine debugging"
517e7aa5 1501 depends on DEBUG_KERNEL && LOCKDEP
997acaf6 1502 select DEBUG_IRQFLAGS
4d9f34ad
IM
1503 help
1504 If you say Y here, the lock dependency engine will do
1505 additional runtime checks to debug itself, at the price
1506 of more runtime overhead.
1507
d902db1e
FW
1508config DEBUG_ATOMIC_SLEEP
1509 bool "Sleep inside atomic section checking"
e8f7c70f 1510 select PREEMPT_COUNT
1da177e4 1511 depends on DEBUG_KERNEL
87a4c375 1512 depends on !ARCH_NO_PREEMPT
1da177e4
LT
1513 help
1514 If you say Y here, various routines which may sleep will become very
d902db1e
FW
1515 noisy if they are called inside atomic sections: when a spinlock is
1516 held, inside an rcu read side critical section, inside preempt disabled
1517 sections, inside an interrupt, etc...
1da177e4 1518
cae2ed9a
IM
1519config DEBUG_LOCKING_API_SELFTESTS
1520 bool "Locking API boot-time self-tests"
1521 depends on DEBUG_KERNEL
1522 help
1523 Say Y here if you want the kernel to run a short self-test during
1524 bootup. The self-test checks whether common types of locking bugs
1525 are detected by debugging mechanisms or not. (if you disable
9dbbc3b9 1526 lock debugging then those bugs won't be detected of course.)
cae2ed9a
IM
1527 The following locking APIs are covered: spinlocks, rwlocks,
1528 mutexes and rwsems.
1529
0af3fe1e
PM
1530config LOCK_TORTURE_TEST
1531 tristate "torture tests for locking"
1532 depends on DEBUG_KERNEL
1533 select TORTURE_TEST
0af3fe1e
PM
1534 help
1535 This option provides a kernel module that runs torture tests
1536 on kernel locking primitives. The kernel module may be built
1537 after the fact on the running kernel to be tested, if desired.
1538
1539 Say Y here if you want kernel locking-primitive torture tests
1540 to be built into the kernel.
1541 Say M if you want these torture tests to build as a module.
1542 Say N if you are unsure.
1543
f2a5fec1
CW
1544config WW_MUTEX_SELFTEST
1545 tristate "Wait/wound mutex selftests"
1546 help
1547 This option provides a kernel module that runs tests on the
1548 on the struct ww_mutex locking API.
1549
1550 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1551 with this test harness.
1552
1553 Say M if you want these self tests to build as a module.
1554 Say N if you are unsure.
1555
e9d338a0
PM
1556config SCF_TORTURE_TEST
1557 tristate "torture tests for smp_call_function*()"
1558 depends on DEBUG_KERNEL
1559 select TORTURE_TEST
1560 help
1561 This option provides a kernel module that runs torture tests
1562 on the smp_call_function() family of primitives. The kernel
1563 module may be built after the fact on the running kernel to
1564 be tested, if desired.
1565
35feb604
PM
1566config CSD_LOCK_WAIT_DEBUG
1567 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1568 depends on DEBUG_KERNEL
1569 depends on 64BIT
1570 default n
1571 help
1572 This option enables debug prints when CPUs are slow to respond
1573 to the smp_call_function*() IPI wrappers. These debug prints
1574 include the IPI handler function currently executing (if any)
1575 and relevant stack traces.
1576
c5219860
PM
1577config CSD_LOCK_WAIT_DEBUG_DEFAULT
1578 bool "Default csd_lock_wait() debugging on at boot time"
1579 depends on CSD_LOCK_WAIT_DEBUG
1580 depends on 64BIT
1581 default n
1582 help
1583 This option causes the csdlock_debug= kernel boot parameter to
1584 default to 1 (basic debugging) instead of 0 (no debugging).
1585
9eade16b 1586endmenu # lock debugging
8637c099 1587
9eade16b 1588config TRACE_IRQFLAGS
ed004953 1589 depends on TRACE_IRQFLAGS_SUPPORT
9eade16b 1590 bool
5ca43f6c 1591 help
9eade16b
DH
1592 Enables hooks to interrupt enabling and disabling for
1593 either tracing or lock debugging.
5ca43f6c 1594
ed004953 1595config TRACE_IRQFLAGS_NMI
1596 def_bool y
1597 depends on TRACE_IRQFLAGS
1598 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1599
1a3ea611
PM
1600config NMI_CHECK_CPU
1601 bool "Debugging for CPUs failing to respond to backtrace requests"
1602 depends on DEBUG_KERNEL
1603 depends on X86
1604 default n
1605 help
1606 Enables debug prints when a CPU fails to respond to a given
1607 backtrace NMI. These prints provide some reasons why a CPU
1608 might legitimately be failing to respond, for example, if it
1609 is offline of if ignore_nmis is set.
1610
997acaf6
MR
1611config DEBUG_IRQFLAGS
1612 bool "Debug IRQ flag manipulation"
1613 help
1614 Enables checks for potentially unsafe enabling or disabling of
1615 interrupts, such as calling raw_local_irq_restore() when interrupts
1616 are enabled.
1617
8637c099 1618config STACKTRACE
0c38e1fe 1619 bool "Stack backtrace support"
8637c099 1620 depends on STACKTRACE_SUPPORT
0c38e1fe
DJ
1621 help
1622 This option causes the kernel to create a /proc/pid/stack for
1623 every process, showing its current stack trace.
1624 It is also used by various kernel debugging features that require
1625 stack trace generation.
5ca43f6c 1626
eecabf56
TT
1627config WARN_ALL_UNSEEDED_RANDOM
1628 bool "Warn for all uses of unseeded randomness"
1629 default n
d06bfd19
JD
1630 help
1631 Some parts of the kernel contain bugs relating to their use of
1632 cryptographically secure random numbers before it's actually possible
1633 to generate those numbers securely. This setting ensures that these
1634 flaws don't go unnoticed, by enabling a message, should this ever
1635 occur. This will allow people with obscure setups to know when things
1636 are going wrong, so that they might contact developers about fixing
1637 it.
1638
eecabf56
TT
1639 Unfortunately, on some models of some architectures getting
1640 a fully seeded CRNG is extremely difficult, and so this can
1641 result in dmesg getting spammed for a surprisingly long
1642 time. This is really bad from a security perspective, and
1643 so architecture maintainers really need to do what they can
1644 to get the CRNG seeded sooner after the system is booted.
4c5d114e 1645 However, since users cannot do anything actionable to
cc1e127b 1646 address this, by default this option is disabled.
eecabf56
TT
1647
1648 Say Y here if you want to receive warnings for all uses of
1649 unseeded randomness. This will be of use primarily for
4c5d114e 1650 those developers interested in improving the security of
eecabf56
TT
1651 Linux kernels running on their architecture (or
1652 subarchitecture).
d06bfd19 1653
1da177e4
LT
1654config DEBUG_KOBJECT
1655 bool "kobject debugging"
1656 depends on DEBUG_KERNEL
1657 help
1658 If you say Y here, some extra kobject debugging messages will be sent
aca52c39 1659 to the syslog.
1da177e4 1660
c817a67e
RK
1661config DEBUG_KOBJECT_RELEASE
1662 bool "kobject release debugging"
2a999aa0 1663 depends on DEBUG_OBJECTS_TIMERS
c817a67e
RK
1664 help
1665 kobjects are reference counted objects. This means that their
1666 last reference count put is not predictable, and the kobject can
b6c69474 1667 live on past the point at which a driver decides to drop its
c817a67e
RK
1668 initial reference to the kobject gained on allocation. An
1669 example of this would be a struct device which has just been
1670 unregistered.
1671
1672 However, some buggy drivers assume that after such an operation,
1673 the memory backing the kobject can be immediately freed. This
1674 goes completely against the principles of a refcounted object.
1675
1676 If you say Y here, the kernel will delay the release of kobjects
1677 on the last reference count to improve the visibility of this
1678 kind of kobject release bug.
1679
9b2a60c4
CM
1680config HAVE_DEBUG_BUGVERBOSE
1681 bool
1682
3be5cbcd 1683menu "Debug kernel data structures"
1da177e4 1684
199a9afc
DJ
1685config DEBUG_LIST
1686 bool "Debug linked list manipulation"
aa9f10d5 1687 depends on DEBUG_KERNEL
aebc7b0d 1688 select LIST_HARDENED
199a9afc 1689 help
aebc7b0d
ME
1690 Enable this to turn on extended checks in the linked-list walking
1691 routines.
1692
1693 This option trades better quality error reports for performance, and
1694 is more suitable for kernel debugging. If you care about performance,
1695 you should only enable CONFIG_LIST_HARDENED instead.
199a9afc
DJ
1696
1697 If unsure, say N.
1698
8e18faea 1699config DEBUG_PLIST
b8cfff68
DS
1700 bool "Debug priority linked list manipulation"
1701 depends on DEBUG_KERNEL
1702 help
1703 Enable this to turn on extended checks in the priority-ordered
1704 linked-list (plist) walking routines. This checks the entire
1705 list multiple times during each manipulation.
1706
1707 If unsure, say N.
1708
d6ec0842
JA
1709config DEBUG_SG
1710 bool "Debug SG table operations"
1711 depends on DEBUG_KERNEL
1712 help
1713 Enable this to turn on checks on scatter-gather tables. This can
1714 help find problems with drivers that do not properly initialize
1715 their sg tables.
1716
1717 If unsure, say N.
1718
1b2439db
AV
1719config DEBUG_NOTIFIERS
1720 bool "Debug notifier call chains"
1721 depends on DEBUG_KERNEL
1722 help
1723 Enable this to turn on sanity checking for notifier call chains.
1724 This is most useful for kernel developers to make sure that
1725 modules properly unregister themselves from notifier chains.
1726 This is a relatively cheap check but if you care about maximum
1727 performance, say N.
1728
8c8d2d96
KO
1729config DEBUG_CLOSURES
1730 bool "Debug closures (bcache async widgits)"
1731 depends on CLOSURES
1732 select DEBUG_FS
1733 help
1734 Keeps all active closures in a linked list and provides a debugfs
1735 interface to list them, which makes it possible to see asynchronous
1736 operations that get stuck.
1737
54a611b6
LH
1738config DEBUG_MAPLE_TREE
1739 bool "Debug maple trees"
1740 depends on DEBUG_KERNEL
1741 help
1742 Enable maple tree debugging information and extra validations.
1743
1744 If unsure, say N.
1745
3be5cbcd
CD
1746endmenu
1747
43a0a2a7 1748source "kernel/rcu/Kconfig.debug"
2f03e3ca 1749
f303fccb
TH
1750config DEBUG_WQ_FORCE_RR_CPU
1751 bool "Force round-robin CPU selection for unbound work items"
1752 depends on DEBUG_KERNEL
1753 default n
1754 help
1755 Workqueue used to implicitly guarantee that work items queued
1756 without explicit CPU specified are put on the local CPU. This
1757 guarantee is no longer true and while local CPU is still
1758 preferred work items may be put on foreign CPUs. Kernel
1759 parameter "workqueue.debug_force_rr_cpu" is added to force
1760 round-robin CPU selection to flush out usages which depend on the
1761 now broken guarantee. This config option enables the debug
1762 feature by default. When enabled, memory and cache locality will
1763 be impacted.
1764
757c989b
TG
1765config CPU_HOTPLUG_STATE_CONTROL
1766 bool "Enable CPU hotplug state control"
1767 depends on DEBUG_KERNEL
1768 depends on HOTPLUG_CPU
1769 default n
1770 help
1771 Allows to write steps between "offline" and "online" to the CPUs
1772 sysfs target file so states can be stepped granular. This is a debug
1773 option for now as the hotplug machinery cannot be stopped and
1774 restarted at arbitrary points yet.
1775
1776 Say N if your are unsure.
1777
09a74952
CD
1778config LATENCYTOP
1779 bool "Latency measuring infrastructure"
1780 depends on DEBUG_KERNEL
1781 depends on STACKTRACE_SUPPORT
1782 depends on PROC_FS
7d37cb2c 1783 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
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1784 select KALLSYMS
1785 select KALLSYMS_ALL
1786 select STACKTRACE
1787 select SCHEDSTATS
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1788 help
1789 Enable this option if you want to use the LatencyTOP tool
1790 to find out which userspace is blocking on what kernel operations.
1791
6ab42860
TH
1792config DEBUG_CGROUP_REF
1793 bool "Disable inlining of cgroup css reference count functions"
1794 depends on DEBUG_KERNEL
1795 depends on CGROUPS
1796 depends on KPROBES
1797 default n
1798 help
1799 Force cgroup css reference count functions to not be inlined so
1800 that they can be kprobed for debugging.
1801
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1802source "kernel/trace/Kconfig"
1803
1804config PROVIDE_OHCI1394_DMA_INIT
1805 bool "Remote debugging over FireWire early on boot"
1806 depends on PCI && X86
1807 help
1808 If you want to debug problems which hang or crash the kernel early
1809 on boot and the crashing machine has a FireWire port, you can use
1810 this feature to remotely access the memory of the crashed machine
1811 over FireWire. This employs remote DMA as part of the OHCI1394
1812 specification which is now the standard for FireWire controllers.
1813
1814 With remote DMA, you can monitor the printk buffer remotely using
1815 firescope and access all memory below 4GB using fireproxy from gdb.
1816 Even controlling a kernel debugger is possible using remote DMA.
1817
1818 Usage:
1819
1820 If ohci1394_dma=early is used as boot parameter, it will initialize
1821 all OHCI1394 controllers which are found in the PCI config space.
1822
1823 As all changes to the FireWire bus such as enabling and disabling
1824 devices cause a bus reset and thereby disable remote DMA for all
1825 devices, be sure to have the cable plugged and FireWire enabled on
1826 the debugging host before booting the debug target for debugging.
1827
1828 This code (~1k) is freed after boot. By then, the firewire stack
1829 in charge of the OHCI-1394 controllers should be used instead.
1830
a74e2a22 1831 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
09a74952 1832
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CD
1833source "samples/Kconfig"
1834
1835config ARCH_HAS_DEVMEM_IS_ALLOWED
1836 bool
1837
1838config STRICT_DEVMEM
1839 bool "Filter access to /dev/mem"
1840 depends on MMU && DEVMEM
527701ed 1841 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
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CD
1842 default y if PPC || X86 || ARM64
1843 help
1844 If this option is disabled, you allow userspace (root) access to all
1845 of memory, including kernel and userspace memory. Accidental
1846 access to this is obviously disastrous, but specific access can
1847 be used by people debugging the kernel. Note that with PAT support
1848 enabled, even in this case there are restrictions on /dev/mem
1849 use due to the cache aliasing requirements.
1850
1851 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1852 file only allows userspace access to PCI space and the BIOS code and
1853 data regions. This is sufficient for dosemu and X and all common
1854 users of /dev/mem.
1855
1856 If in doubt, say Y.
1857
1858config IO_STRICT_DEVMEM
1859 bool "Filter I/O access to /dev/mem"
1860 depends on STRICT_DEVMEM
1861 help
1862 If this option is disabled, you allow userspace (root) access to all
1863 io-memory regardless of whether a driver is actively using that
1864 range. Accidental access to this is obviously disastrous, but
1865 specific access can be used by people debugging kernel drivers.
1866
1867 If this option is switched on, the /dev/mem file only allows
1868 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1869 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1870 if the driver using a given range cannot be disabled.
1871
1872 If in doubt, say Y.
1873
1874menu "$(SRCARCH) Debugging"
1875
1876source "arch/$(SRCARCH)/Kconfig.debug"
1877
1878endmenu
1879
1880menu "Kernel Testing and Coverage"
1881
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1882source "lib/kunit/Kconfig"
1883
8d438288
AM
1884config NOTIFIER_ERROR_INJECTION
1885 tristate "Notifier error injection"
1886 depends on DEBUG_KERNEL
1887 select DEBUG_FS
1888 help
e41e85cc 1889 This option provides the ability to inject artificial errors to
8d438288
AM
1890 specified notifier chain callbacks. It is useful to test the error
1891 handling of notifier call chain failures.
1892
1893 Say N if unsure.
1894
048b9c35
AM
1895config PM_NOTIFIER_ERROR_INJECT
1896 tristate "PM notifier error injection module"
1897 depends on PM && NOTIFIER_ERROR_INJECTION
1898 default m if PM_DEBUG
1899 help
e41e85cc 1900 This option provides the ability to inject artificial errors to
048b9c35
AM
1901 PM notifier chain callbacks. It is controlled through debugfs
1902 interface /sys/kernel/debug/notifier-error-inject/pm
1903
1904 If the notifier call chain should be failed with some events
1905 notified, write the error code to "actions/<notifier event>/error".
1906
1907 Example: Inject PM suspend error (-12 = -ENOMEM)
1908
1909 # cd /sys/kernel/debug/notifier-error-inject/pm/
1910 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1911 # echo mem > /sys/power/state
1912 bash: echo: write error: Cannot allocate memory
1913
1914 To compile this code as a module, choose M here: the module will
1915 be called pm-notifier-error-inject.
1916
1917 If unsure, say N.
1918
d526e85f
BH
1919config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1920 tristate "OF reconfig notifier error injection module"
1921 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dd 1922 help
e41e85cc 1923 This option provides the ability to inject artificial errors to
d526e85f 1924 OF reconfig notifier chain callbacks. It is controlled
08dfb4dd 1925 through debugfs interface under
d526e85f 1926 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
08dfb4dd
AM
1927
1928 If the notifier call chain should be failed with some events
1929 notified, write the error code to "actions/<notifier event>/error".
1930
1931 To compile this code as a module, choose M here: the module will
e12a95f4 1932 be called of-reconfig-notifier-error-inject.
08dfb4dd
AM
1933
1934 If unsure, say N.
1935
02fff96a
NA
1936config NETDEV_NOTIFIER_ERROR_INJECT
1937 tristate "Netdev notifier error injection module"
1938 depends on NET && NOTIFIER_ERROR_INJECTION
1939 help
1940 This option provides the ability to inject artificial errors to
1941 netdevice notifier chain callbacks. It is controlled through debugfs
1942 interface /sys/kernel/debug/notifier-error-inject/netdev
1943
1944 If the notifier call chain should be failed with some events
1945 notified, write the error code to "actions/<notifier event>/error".
1946
1947 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1948
1949 # cd /sys/kernel/debug/notifier-error-inject/netdev
1950 # echo -22 > actions/NETDEV_CHANGEMTU/error
1951 # ip link set eth0 mtu 1024
1952 RTNETLINK answers: Invalid argument
1953
1954 To compile this code as a module, choose M here: the module will
1955 be called netdev-notifier-error-inject.
1956
1957 If unsure, say N.
1958
f1b4bd06 1959config FUNCTION_ERROR_INJECTION
a4412fdd 1960 bool "Fault-injections of functions"
f1b4bd06 1961 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
a4412fdd
SRG
1962 help
1963 Add fault injections into various functions that are annotated with
1964 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
ca0f2cfc 1965 value of these functions. This is useful to test error paths of code.
a4412fdd
SRG
1966
1967 If unsure, say N
f1b4bd06 1968
6ff1cb35 1969config FAULT_INJECTION
1ab8509a
AM
1970 bool "Fault-injection framework"
1971 depends on DEBUG_KERNEL
329409ae
AM
1972 help
1973 Provide fault-injection framework.
1974 For more details, see Documentation/fault-injection/.
6ff1cb35 1975
8a8b6502 1976config FAILSLAB
1ab8509a
AM
1977 bool "Fault-injection capability for kmalloc"
1978 depends on FAULT_INJECTION
8a8b6502 1979 help
1ab8509a 1980 Provide fault-injection capability for kmalloc.
8a8b6502 1981
933e312e 1982config FAIL_PAGE_ALLOC
29b46fa3 1983 bool "Fault-injection capability for alloc_pages()"
1ab8509a 1984 depends on FAULT_INJECTION
933e312e 1985 help
1ab8509a 1986 Provide fault-injection capability for alloc_pages().
933e312e 1987
2c739ced
AL
1988config FAULT_INJECTION_USERCOPY
1989 bool "Fault injection capability for usercopy functions"
1990 depends on FAULT_INJECTION
1991 help
1992 Provides fault-injection capability to inject failures
1993 in usercopy functions (copy_from_user(), get_user(), ...).
1994
c17bb495 1995config FAIL_MAKE_REQUEST
86327d19 1996 bool "Fault-injection capability for disk IO"
581d4e28 1997 depends on FAULT_INJECTION && BLOCK
c17bb495 1998 help
1ab8509a 1999 Provide fault-injection capability for disk IO.
c17bb495 2000
581d4e28 2001config FAIL_IO_TIMEOUT
f4d01439 2002 bool "Fault-injection capability for faking disk interrupts"
581d4e28
JA
2003 depends on FAULT_INJECTION && BLOCK
2004 help
2005 Provide fault-injection capability on end IO handling. This
2006 will make the block layer "forget" an interrupt as configured,
2007 thus exercising the error handling.
2008
2009 Only works with drivers that use the generic timeout handling,
9dbbc3b9 2010 for others it won't do anything.
581d4e28 2011
ab51fbab
DB
2012config FAIL_FUTEX
2013 bool "Fault-injection capability for futexes"
2014 select DEBUG_FS
2015 depends on FAULT_INJECTION && FUTEX
2016 help
2017 Provide fault-injection capability for futexes.
2018
f1b4bd06
MP
2019config FAULT_INJECTION_DEBUG_FS
2020 bool "Debugfs entries for fault-injection capabilities"
2021 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2022 help
2023 Enable configuration of fault-injection capabilities via debugfs.
2024
4b1a29a7
MH
2025config FAIL_FUNCTION
2026 bool "Fault-injection capability for functions"
2027 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2028 help
2029 Provide function-based fault-injection capability.
2030 This will allow you to override a specific function with a return
2031 with given return value. As a result, function caller will see
2032 an error value and have to handle it. This is useful to test the
2033 error handling in various subsystems.
2034
f1b4bd06
MP
2035config FAIL_MMC_REQUEST
2036 bool "Fault-injection capability for MMC IO"
2037 depends on FAULT_INJECTION_DEBUG_FS && MMC
6ff1cb35 2038 help
f1b4bd06
MP
2039 Provide fault-injection capability for MMC IO.
2040 This will make the mmc core return data errors. This is
2041 useful to test the error handling in the mmc block device
2042 and to test how the mmc host driver handles retries from
2043 the block device.
1df49008 2044
c782af25
CL
2045config FAIL_SUNRPC
2046 bool "Fault-injection capability for SunRPC"
2047 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2048 help
2049 Provide fault-injection capability for SunRPC and
2050 its consumers.
2051
4668c7a2
AM
2052config FAULT_INJECTION_CONFIGFS
2053 bool "Configfs interface for fault-injection capabilities"
d325c162
AM
2054 depends on FAULT_INJECTION
2055 select CONFIGFS_FS
4668c7a2
AM
2056 help
2057 This option allows configfs-based drivers to dynamically configure
2058 fault-injection via configfs. Each parameter for driver-specific
2059 fault-injection can be made visible as a configfs attribute in a
2060 configfs group.
2061
2062
1df49008
AM
2063config FAULT_INJECTION_STACKTRACE_FILTER
2064 bool "stacktrace filter for fault-injection capabilities"
4668c7a2
AM
2065 depends on FAULT_INJECTION
2066 depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
1df49008 2067 select STACKTRACE
7d37cb2c 2068 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1df49008
AM
2069 help
2070 Provide stacktrace filter for fault-injection capabilities
267c4025 2071
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2072config ARCH_HAS_KCOV
2073 bool
cc3fa840 2074 help
09a74952
CD
2075 An architecture should select this when it can successfully
2076 build and run with CONFIG_KCOV. This typically requires
2077 disabling instrumentation for some early boot code.
cc3fa840 2078
09a74952
CD
2079config CC_HAS_SANCOV_TRACE_PC
2080 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
cc3fa840 2081
cc3fa840 2082
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CD
2083config KCOV
2084 bool "Code coverage for fuzzing"
2085 depends on ARCH_HAS_KCOV
2086 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
22102f45 2087 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
9feceff1 2088 GCC_VERSION >= 120000 || CC_IS_CLANG
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CD
2089 select DEBUG_FS
2090 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
22102f45 2091 select OBJTOOL if HAVE_NOINSTR_HACK
09a74952
CD
2092 help
2093 KCOV exposes kernel code coverage information in a form suitable
2094 for coverage-guided fuzzing (randomized testing).
cc3fa840 2095
09a74952 2096 For more details, see Documentation/dev-tools/kcov.rst.
cc3fa840 2097
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CD
2098config KCOV_ENABLE_COMPARISONS
2099 bool "Enable comparison operands collection by KCOV"
2100 depends on KCOV
2101 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2102 help
2103 KCOV also exposes operands of every comparison in the instrumented
2104 code along with operand sizes and PCs of the comparison instructions.
2105 These operands can be used by fuzzing engines to improve the quality
2106 of fuzzing coverage.
cc3fa840 2107
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CD
2108config KCOV_INSTRUMENT_ALL
2109 bool "Instrument all code by default"
2110 depends on KCOV
2111 default y
2112 help
2113 If you are doing generic system call fuzzing (like e.g. syzkaller),
2114 then you will want to instrument the whole kernel and you should
2115 say y here. If you are doing more targeted fuzzing (like e.g.
2116 filesystem fuzzing with AFL) then you will want to enable coverage
2117 for more specific subsets of files, and should say n here.
84bc809e 2118
5ff3b30a
AK
2119config KCOV_IRQ_AREA_SIZE
2120 hex "Size of interrupt coverage collection area in words"
2121 depends on KCOV
2122 default 0x40000
2123 help
2124 KCOV uses preallocated per-cpu areas to collect coverage from
2125 soft interrupts. This specifies the size of those areas in the
2126 number of unsigned long words.
2127
d3deafaa
VL
2128menuconfig RUNTIME_TESTING_MENU
2129 bool "Runtime Testing"
cd14b018 2130 default y
d3deafaa
VL
2131
2132if RUNTIME_TESTING_MENU
881c5149 2133
d5528cc1
GU
2134config TEST_DHRY
2135 tristate "Dhrystone benchmark test"
2136 help
2137 Enable this to include the Dhrystone 2.1 benchmark. This test
2138 calculates the number of Dhrystones per second, and the number of
2139 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2140 by 1757 (the number of Dhrystones per second obtained on the VAX
2141 11/780, nominally a 1 MIPS machine).
2142
2143 To run the benchmark, it needs to be enabled explicitly, either from
2144 the kernel command line (when built-in), or from userspace (when
f785785c 2145 built-in or modular).
d5528cc1
GU
2146
2147 Run once during kernel boot:
2148
2149 test_dhry.run
2150
2151 Set number of iterations from kernel command line:
2152
2153 test_dhry.iterations=<n>
2154
2155 Set number of iterations from userspace:
2156
2157 echo <n> > /sys/module/test_dhry/parameters/iterations
2158
2159 Trigger manual run from userspace:
2160
2161 echo y > /sys/module/test_dhry/parameters/run
2162
2163 If the number of iterations is <= 0, the test will devise a suitable
2164 number of iterations (test runs for at least 2s) automatically.
2165 This process takes ca. 4s.
2166
2167 If unsure, say N.
2168
881c5149
DH
2169config LKDTM
2170 tristate "Linux Kernel Dump Test Tool Module"
2171 depends on DEBUG_FS
881c5149
DH
2172 help
2173 This module enables testing of the different dumping mechanisms by
2174 inducing system failures at predefined crash points.
2175 If you don't need it: say N
2176 Choose M here to compile this code as a module. The module will be
2177 called lkdtm.
2178
2179 Documentation on how to use the module can be found in
10ffebbe 2180 Documentation/fault-injection/provoke-crashes.rst
881c5149 2181
d3c0ca49
SV
2182config CPUMASK_KUNIT_TEST
2183 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
c41e8866
SV
2184 depends on KUNIT
2185 default KUNIT_ALL_TESTS
2186 help
2187 Enable to turn on cpumask tests, running at boot or module load time.
2188
d3c0ca49
SV
2189 For more information on KUnit and unit tests in general, please refer
2190 to the KUnit documentation in Documentation/dev-tools/kunit/.
2191
c41e8866
SV
2192 If unsure, say N.
2193
881c5149 2194config TEST_LIST_SORT
ebd09577
DL
2195 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2196 depends on KUNIT
2197 default KUNIT_ALL_TESTS
881c5149
DH
2198 help
2199 Enable this to turn on 'list_sort()' function test. This test is
e327fd7c
GU
2200 executed only once during system boot (so affects only boot time),
2201 or at module load time.
881c5149
DH
2202
2203 If unsure, say N.
2204
6e24628d
IR
2205config TEST_MIN_HEAP
2206 tristate "Min heap test"
2207 depends on DEBUG_KERNEL || m
2208 help
2209 Enable this to turn on min heap function tests. This test is
2210 executed only once during system boot (so affects only boot time),
2211 or at module load time.
2212
2213 If unsure, say N.
2214
c5adae95 2215config TEST_SORT
36f33b56
DL
2216 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2217 depends on KUNIT
2218 default KUNIT_ALL_TESTS
c5adae95 2219 help
5c4e6798
GU
2220 This option enables the self-test function of 'sort()' at boot,
2221 or at module load time.
c5adae95
KF
2222
2223 If unsure, say N.
2224
5086ea4b
MR
2225config TEST_DIV64
2226 tristate "64bit/32bit division and modulo test"
2227 depends on DEBUG_KERNEL || m
2228 help
2229 Enable this to turn on 'do_div()' function test. This test is
2230 executed only once during system boot (so affects only boot time),
2231 or at module load time.
2232
2233 If unsure, say N.
2234
2d71340f
DH
2235config TEST_IOV_ITER
2236 tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS
2237 depends on KUNIT
1eb1e984 2238 depends on MMU
2d71340f
DH
2239 default KUNIT_ALL_TESTS
2240 help
2241 Enable this to turn on testing of the operation of the I/O iterator
2242 (iov_iter). This test is executed only once during system boot (so
2243 affects only boot time), or at module load time.
2244
2245 If unsure, say N.
2246
881c5149 2247config KPROBES_SANITY_TEST
dcbb2ee2 2248 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
881c5149
DH
2249 depends on DEBUG_KERNEL
2250 depends on KPROBES
e44e81c5 2251 depends on KUNIT
de3db3f8 2252 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
dcbb2ee2 2253 default KUNIT_ALL_TESTS
881c5149
DH
2254 help
2255 This option provides for testing basic kprobes functionality on
5a6cf77f 2256 boot. Samples of kprobe and kretprobe are inserted and
881c5149
DH
2257 verified for functionality.
2258
2259 Say N if you are unsure.
2260
f4616fab
MH
2261config FPROBE_SANITY_TEST
2262 bool "Self test for fprobe"
2263 depends on DEBUG_KERNEL
2264 depends on FPROBE
2265 depends on KUNIT=y
2266 help
2267 This option will enable testing the fprobe when the system boot.
2268 A series of tests are made to verify that the fprobe is functioning
2269 properly.
2270
2271 Say N if you are unsure.
2272
881c5149
DH
2273config BACKTRACE_SELF_TEST
2274 tristate "Self test for the backtrace code"
2275 depends on DEBUG_KERNEL
881c5149
DH
2276 help
2277 This option provides a kernel module that can be used to test
2278 the kernel stack backtrace code. This option is not useful
2279 for distributions or general kernels, but only for kernel
2280 developers working on architecture code.
2281
2282 Note that if you want to also test saved backtraces, you will
2283 have to enable STACKTRACE as well.
2284
2285 Say N if you are unsure.
2286
914a7b50
ED
2287config TEST_REF_TRACKER
2288 tristate "Self test for reference tracker"
2289 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2290 select REF_TRACKER
2291 help
2292 This option provides a kernel module performing tests
2293 using reference tracker infrastructure.
2294
2295 Say N if you are unsure.
2296
910a742d
ML
2297config RBTREE_TEST
2298 tristate "Red-Black tree test"
7c993e11 2299 depends on DEBUG_KERNEL
910a742d
ML
2300 help
2301 A benchmark measuring the performance of the rbtree library.
2302 Also includes rbtree invariant checks.
2303
4b4f3acc
FB
2304config REED_SOLOMON_TEST
2305 tristate "Reed-Solomon library test"
2306 depends on DEBUG_KERNEL || m
2307 select REED_SOLOMON
2308 select REED_SOLOMON_ENC16
2309 select REED_SOLOMON_DEC16
2310 help
2311 This option enables the self-test function of rslib at boot,
2312 or at module load time.
2313
2314 If unsure, say N.
2315
fff3fd8a
ML
2316config INTERVAL_TREE_TEST
2317 tristate "Interval tree test"
0f789b67 2318 depends on DEBUG_KERNEL
a88cc108 2319 select INTERVAL_TREE
fff3fd8a
ML
2320 help
2321 A benchmark measuring the performance of the interval tree library
2322
623fd807
GT
2323config PERCPU_TEST
2324 tristate "Per cpu operations test"
2325 depends on m && DEBUG_KERNEL
2326 help
2327 Enable this option to build test module which validates per-cpu
2328 operations.
2329
2330 If unsure, say N.
2331
881c5149 2332config ATOMIC64_SELFTEST
55ded955 2333 tristate "Perform an atomic64_t self-test"
881c5149 2334 help
55ded955
GU
2335 Enable this option to test the atomic64_t functions at boot or
2336 at module load time.
881c5149
DH
2337
2338 If unsure, say N.
2339
2340config ASYNC_RAID6_TEST
2341 tristate "Self test for hardware accelerated raid6 recovery"
2342 depends on ASYNC_RAID6_RECOV
2343 select ASYNC_MEMCPY
a7f7f624 2344 help
881c5149
DH
2345 This is a one-shot self test that permutes through the
2346 recovery of all the possible two disk failure scenarios for a
2347 N-disk array. Recovery is performed with the asynchronous
2348 raid6 recovery routines, and will optionally use an offload
2349 engine if one is available.
2350
2351 If unsure, say N.
2352
64d1d77a
AS
2353config TEST_HEXDUMP
2354 tristate "Test functions located in the hexdump module at runtime"
2355
29d85688
KC
2356config STRING_KUNIT_TEST
2357 tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS
2358 depends on KUNIT
2359 default KUNIT_ALL_TESTS
b2ff70a0 2360
fb57550f
KC
2361config STRING_HELPERS_KUNIT_TEST
2362 tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS
2363 depends on KUNIT
2364 default KUNIT_ALL_TESTS
881c5149
DH
2365
2366config TEST_KSTRTOX
2367 tristate "Test kstrto*() family of functions at runtime"
2368
707cc728
RV
2369config TEST_PRINTF
2370 tristate "Test printf() family of functions at runtime"
2371
50f530e1
RF
2372config TEST_SCANF
2373 tristate "Test scanf() family of functions at runtime"
2374
5fd003f5
DD
2375config TEST_BITMAP
2376 tristate "Test bitmap_*() family of functions at runtime"
5fd003f5
DD
2377 help
2378 Enable this option to test the bitmap functions at boot.
2379
2380 If unsure, say N.
2381
cfaff0e5
AS
2382config TEST_UUID
2383 tristate "Test functions located in the uuid module at runtime"
2384
ad3d6c72
MW
2385config TEST_XARRAY
2386 tristate "Test the XArray code at runtime"
2387
120b1162 2388config TEST_MAPLE_TREE
a5199577
LH
2389 tristate "Test the Maple Tree code at runtime or module load"
2390 help
2391 Enable this option to test the maple tree code functions at boot, or
2392 when the module is loaded. Enable "Debug Maple Trees" will enable
2393 more verbose output on failures.
2394
2395 If unsure, say N.
120b1162 2396
7e1e7763 2397config TEST_RHASHTABLE
9d6dbe1b 2398 tristate "Perform selftest on resizable hash table"
7e1e7763
TG
2399 help
2400 Enable this option to test the rhashtable functions at boot.
2401
2402 If unsure, say N.
2403
8ab8ba38
MW
2404config TEST_IDA
2405 tristate "Perform selftest on IDA functions"
2406
44091d29
JP
2407config TEST_PARMAN
2408 tristate "Perform selftest on priority array manager"
44091d29
JP
2409 depends on PARMAN
2410 help
2411 Enable this option to test priority array manager on boot
2412 (or module load).
2413
2414 If unsure, say N.
2415
6aed82de
DL
2416config TEST_IRQ_TIMINGS
2417 bool "IRQ timings selftest"
2418 depends on IRQ_TIMINGS
2419 help
2420 Enable this option to test the irq timings code on boot.
2421
2422 If unsure, say N.
2423
8a6f0b47 2424config TEST_LKM
93e9ef83 2425 tristate "Test module loading with 'hello world' module"
93e9ef83
KC
2426 depends on m
2427 help
2428 This builds the "test_module" module that emits "Hello, world"
2429 on printk when loaded. It is designed to be used for basic
2430 evaluation of the module loading subsystem (for example when
2431 validating module verification). It lacks any extra dependencies,
2432 and will not normally be loaded by the system unless explicitly
2433 requested by name.
2434
2435 If unsure, say N.
2436
c348c163 2437config TEST_BITOPS
6af132f3 2438 tristate "Test module for compilation of bitops operations"
c348c163
JB
2439 depends on m
2440 help
2441 This builds the "test_bitops" module that is much like the
2442 TEST_LKM module except that it does a basic exercise of the
6af132f3
WY
2443 set/clear_bit macros and get_count_order/long to make sure there are
2444 no compiler warnings from C=1 sparse checker or -Wextra
2445 compilations. It has no dependencies and doesn't run or load unless
2446 explicitly requested by name. for example: modprobe test_bitops.
c348c163
JB
2447
2448 If unsure, say N.
2449
3f21a6b7
URS
2450config TEST_VMALLOC
2451 tristate "Test module for stress/performance analysis of vmalloc allocator"
2452 default n
2453 depends on MMU
2454 depends on m
2455 help
2456 This builds the "test_vmalloc" module that should be used for
2457 stress and performance analysis. So, any new change for vmalloc
2458 subsystem can be evaluated from performance and stability point
2459 of view.
2460
2461 If unsure, say N.
2462
3e2a4c18
KC
2463config TEST_USER_COPY
2464 tristate "Test user/kernel boundary protections"
3e2a4c18
KC
2465 depends on m
2466 help
2467 This builds the "test_user_copy" module that runs sanity checks
2468 on the copy_to/from_user infrastructure, making sure basic
2469 user/kernel boundary testing is working. If it fails to load,
2470 a regression has been detected in the user/kernel memory boundary
2471 protections.
2472
2473 If unsure, say N.
2474
64a8946b
AS
2475config TEST_BPF
2476 tristate "Test BPF filter functionality"
98920ba6 2477 depends on m && NET
64a8946b
AS
2478 help
2479 This builds the "test_bpf" module that runs various test vectors
2480 against the BPF interpreter or BPF JIT compiler depending on the
2481 current setting. This is in particular useful for BPF JIT compiler
2482 development, but also to run regression tests against changes in
3c731eba
AS
2483 the interpreter code. It also enables test stubs for eBPF maps and
2484 verifier used by user space verifier testsuite.
64a8946b
AS
2485
2486 If unsure, say N.
2487
509e56b3
MB
2488config TEST_BLACKHOLE_DEV
2489 tristate "Test blackhole netdev functionality"
2490 depends on m && NET
2491 help
2492 This builds the "test_blackhole_dev" module that validates the
2493 data path through this blackhole netdev.
2494
2495 If unsure, say N.
2496
dceeb3e7 2497config FIND_BIT_BENCHMARK
4441fca0 2498 tristate "Test find_bit functions"
4441fca0
YN
2499 help
2500 This builds the "test_find_bit" module that measure find_*_bit()
2501 functions performance.
2502
2503 If unsure, say N.
2504
0a8adf58
KC
2505config TEST_FIRMWARE
2506 tristate "Test firmware loading via userspace interface"
0a8adf58
KC
2507 depends on FW_LOADER
2508 help
2509 This builds the "test_firmware" module that creates a userspace
2510 interface for testing firmware loading. This can be used to
2511 control the triggering of firmware loading without needing an
2512 actual firmware-using device. The contents can be rechecked by
2513 userspace.
2514
2515 If unsure, say N.
2516
9308f2f9
LR
2517config TEST_SYSCTL
2518 tristate "sysctl test driver"
9308f2f9
LR
2519 depends on PROC_SYSCTL
2520 help
2521 This builds the "test_sysctl" module. This driver enables to test the
2522 proc sysctl interfaces available to drivers safely without affecting
2523 production knobs which might alter system functionality.
2524
2525 If unsure, say N.
2526
d2585f51 2527config BITFIELD_KUNIT
dcbb2ee2 2528 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
d2585f51 2529 depends on KUNIT
dcbb2ee2 2530 default KUNIT_ALL_TESTS
d2585f51
VMI
2531 help
2532 Enable this option to test the bitfield functions at boot.
2533
2534 KUnit tests run during boot and output the results to the debug log
2535 in TAP format (http://testanything.org/). Only useful for kernel devs
2536 running the KUnit test harness, and not intended for inclusion into a
2537 production build.
2538
2539 For more information on KUnit and unit tests in general please refer
2540 to the KUnit documentation in Documentation/dev-tools/kunit/.
2541
2542 If unsure, say N.
2543
688eb819
NG
2544config CHECKSUM_KUNIT
2545 tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2546 depends on KUNIT
2547 default KUNIT_ALL_TESTS
2548 help
2549 Enable this option to test the checksum functions at boot.
2550
2551 KUnit tests run during boot and output the results to the debug log
2552 in TAP format (http://testanything.org/). Only useful for kernel devs
2553 running the KUnit test harness, and not intended for inclusion into a
2554 production build.
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
0acc968f
IB
2561config HASH_KUNIT_TEST
2562 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2563 depends on KUNIT
2564 default KUNIT_ALL_TESTS
2565 help
2566 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2567 integer (<linux/hash.h>) hash functions on boot.
2568
2569 KUnit tests run during boot and output the results to the debug log
2570 in TAP format (https://testanything.org/). Only useful for kernel devs
2571 running the KUnit test harness, and not intended for inclusion into a
2572 production build.
2573
2574 For more information on KUnit and unit tests in general please refer
2575 to the KUnit documentation in Documentation/dev-tools/kunit/.
2576
2577 This is intended to help people writing architecture-specific
2578 optimized versions. If unsure, say N.
2579
5df38ca6 2580config RESOURCE_KUNIT_TEST
dcbb2ee2 2581 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
5df38ca6 2582 depends on KUNIT
dcbb2ee2 2583 default KUNIT_ALL_TESTS
5df38ca6
AS
2584 help
2585 This builds the resource API unit test.
2586 Tests the logic of API provided by resource.c and ioport.h.
2587 For more information on KUnit and unit tests in general please refer
2588 to the KUnit documentation in Documentation/dev-tools/kunit/.
2589
2590 If unsure, say N.
2591
2cb80dbb 2592config SYSCTL_KUNIT_TEST
5f215aab 2593 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2cb80dbb 2594 depends on KUNIT
5f215aab 2595 default KUNIT_ALL_TESTS
2cb80dbb
IZ
2596 help
2597 This builds the proc sysctl unit test, which runs on boot.
2598 Tests the API contract and implementation correctness of sysctl.
2599 For more information on KUnit and unit tests in general please refer
2600 to the KUnit documentation in Documentation/dev-tools/kunit/.
2601
2602 If unsure, say N.
2603
ea2dd7c0 2604config LIST_KUNIT_TEST
5f215aab 2605 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
ea2dd7c0 2606 depends on KUNIT
5f215aab 2607 default KUNIT_ALL_TESTS
ea2dd7c0
DG
2608 help
2609 This builds the linked list KUnit test suite.
2610 It tests that the API and basic functionality of the list_head type
2611 and associated macros.
2612
2613 KUnit tests run during boot and output the results to the debug log
d89775fc 2614 in TAP format (https://testanything.org/). Only useful for kernel devs
ea2dd7c0
DG
2615 running the KUnit test harness, and not intended for inclusion into a
2616 production build.
2617
2618 For more information on KUnit and unit tests in general please refer
2619 to the KUnit documentation in Documentation/dev-tools/kunit/.
2620
2621 If unsure, say N.
2622
789538c6
RM
2623config HASHTABLE_KUNIT_TEST
2624 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2625 depends on KUNIT
2626 default KUNIT_ALL_TESTS
2627 help
2628 This builds the hashtable KUnit test suite.
2629 It tests the basic functionality of the API defined in
2630 include/linux/hashtable.h. For more information on KUnit and
2631 unit tests in general please refer to the KUnit documentation
2632 in Documentation/dev-tools/kunit/.
2633
2634 If unsure, say N.
2635
33d599f0
MV
2636config LINEAR_RANGES_TEST
2637 tristate "KUnit test for linear_ranges"
2638 depends on KUNIT
2639 select LINEAR_RANGES
2640 help
2641 This builds the linear_ranges unit test, which runs on boot.
2642 Tests the linear_ranges logic correctness.
2643 For more information on KUnit and unit tests in general please refer
7546861a
AS
2644 to the KUnit documentation in Documentation/dev-tools/kunit/.
2645
2646 If unsure, say N.
2647
2648config CMDLINE_KUNIT_TEST
dcbb2ee2 2649 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
7546861a 2650 depends on KUNIT
dcbb2ee2 2651 default KUNIT_ALL_TESTS
7546861a
AS
2652 help
2653 This builds the cmdline API unit test.
2654 Tests the logic of API provided by cmdline.c.
2655 For more information on KUnit and unit tests in general please refer
33d599f0
MV
2656 to the KUnit documentation in Documentation/dev-tools/kunit/.
2657
2658 If unsure, say N.
2659
6d511020 2660config BITS_TEST
dcbb2ee2 2661 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
6d511020 2662 depends on KUNIT
dcbb2ee2 2663 default KUNIT_ALL_TESTS
6d511020
RF
2664 help
2665 This builds the bits unit test.
2666 Tests the logic of macros defined in bits.h.
2667 For more information on KUnit and unit tests in general please refer
2668 to the KUnit documentation in Documentation/dev-tools/kunit/.
2669
2670 If unsure, say N.
2671
1f9f78b1
OG
2672config SLUB_KUNIT_TEST
2673 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2674 depends on SLUB_DEBUG && KUNIT
2675 default KUNIT_ALL_TESTS
2676 help
2677 This builds SLUB allocator unit test.
2678 Tests SLUB cache debugging functionality.
2679 For more information on KUnit and unit tests in general please refer
2680 to the KUnit documentation in Documentation/dev-tools/kunit/.
2681
2682 If unsure, say N.
2683
b6c75c4a
TP
2684config RATIONAL_KUNIT_TEST
2685 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
8ba739ed 2686 depends on KUNIT && RATIONAL
b6c75c4a
TP
2687 default KUNIT_ALL_TESTS
2688 help
2689 This builds the rational math unit test.
2690 For more information on KUnit and unit tests in general please refer
2691 to the KUnit documentation in Documentation/dev-tools/kunit/.
2692
2693 If unsure, say N.
2694
bb95ebbe
KC
2695config MEMCPY_KUNIT_TEST
2696 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2697 depends on KUNIT
2698 default KUNIT_ALL_TESTS
2699 help
2700 Builds unit tests for memcpy(), memmove(), and memset() functions.
2701 For more information on KUnit and unit tests in general please refer
2702 to the KUnit documentation in Documentation/dev-tools/kunit/.
2703
2704 If unsure, say N.
2705
4acf1de3
KC
2706config MEMCPY_SLOW_KUNIT_TEST
2707 bool "Include exhaustive memcpy tests"
2708 depends on MEMCPY_KUNIT_TEST
2709 default y
2710 help
2711 Some memcpy tests are quite exhaustive in checking for overlaps
2712 and bit ranges. These can be very slow, so they are split out
2713 as a separate config, in case they need to be disabled.
2714
d055c6a2
RM
2715 Note this config option will be replaced by the use of KUnit test
2716 attributes.
2717
addbeea6
BVA
2718config IS_SIGNED_TYPE_KUNIT_TEST
2719 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2720 depends on KUNIT
2721 default KUNIT_ALL_TESTS
2722 help
2723 Builds unit tests for the is_signed_type() macro.
2724
2725 For more information on KUnit and unit tests in general please refer
2726 to the KUnit documentation in Documentation/dev-tools/kunit/.
2727
2728 If unsure, say N.
2729
617f55e2
KC
2730config OVERFLOW_KUNIT_TEST
2731 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2732 depends on KUNIT
2733 default KUNIT_ALL_TESTS
2734 help
2735 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2736 related functions.
2737
2738 For more information on KUnit and unit tests in general please refer
2739 to the KUnit documentation in Documentation/dev-tools/kunit/.
2740
2741 If unsure, say N.
2742
02788ebc
KC
2743config STACKINIT_KUNIT_TEST
2744 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2745 depends on KUNIT
2746 default KUNIT_ALL_TESTS
2747 help
2748 Test if the kernel is zero-initializing stack variables and
2749 padding. Coverage is controlled by compiler flags,
2750 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2751 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2752 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2753
875bfd52
KC
2754config FORTIFY_KUNIT_TEST
2755 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
1a78f8cb 2756 depends on KUNIT
875bfd52
KC
2757 default KUNIT_ALL_TESTS
2758 help
2759 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2760 by the str*() and mem*() family of functions. For testing runtime
2761 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2762
724c299c
ME
2763config HW_BREAKPOINT_KUNIT_TEST
2764 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2765 depends on HAVE_HW_BREAKPOINT
2766 depends on KUNIT=y
2767 default KUNIT_ALL_TESTS
2768 help
2769 Tests for hw_breakpoint constraints accounting.
2770
2771 If unsure, say N.
2772
3bf301e1
KC
2773config STRCAT_KUNIT_TEST
2774 tristate "Test strcat() family of functions at runtime" if !KUNIT_ALL_TESTS
2775 depends on KUNIT
2776 default KUNIT_ALL_TESTS
2777
41eefc46
KC
2778config STRSCPY_KUNIT_TEST
2779 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2780 depends on KUNIT
2781 default KUNIT_ALL_TESTS
2782
fb3d88ab
KC
2783config SIPHASH_KUNIT_TEST
2784 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2785 depends on KUNIT
2786 default KUNIT_ALL_TESTS
2787 help
2788 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2789 functions on boot (or module load).
2790
2791 This is intended to help people writing architecture-specific
2792 optimized versions. If unsure, say N.
2793
e704f93a
DR
2794config TEST_UDELAY
2795 tristate "udelay test driver"
e704f93a
DR
2796 help
2797 This builds the "udelay_test" module that helps to make sure
2798 that udelay() is working properly.
2799
2800 If unsure, say N.
2801
2bf9e0ab
IM
2802config TEST_STATIC_KEYS
2803 tristate "Test static keys"
579e1acb
JB
2804 depends on m
2805 help
2bf9e0ab 2806 Test the static key interfaces.
579e1acb
JB
2807
2808 If unsure, say N.
2809
683263a5
JC
2810config TEST_DYNAMIC_DEBUG
2811 tristate "Test DYNAMIC_DEBUG"
2812 depends on DYNAMIC_DEBUG
2813 help
2814 This module registers a tracer callback to count enabled
2815 pr_debugs in a 'do_debugging' function, then alters their
2816 enablements, calls the function, and compares counts.
2817
2818 If unsure, say N.
2819
d9c6a72d
LR
2820config TEST_KMOD
2821 tristate "kmod stress tester"
d9c6a72d 2822 depends on m
d9c6a72d 2823 depends on NETDEVICES && NET_CORE && INET # for TUN
ae3d6a32 2824 depends on BLOCK
bbd2e05f 2825 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
d9c6a72d
LR
2826 select TEST_LKM
2827 select XFS_FS
2828 select TUN
2829 select BTRFS_FS
2830 help
2831 Test the kernel's module loading mechanism: kmod. kmod implements
2832 support to load modules using the Linux kernel's usermode helper.
2833 This test provides a series of tests against kmod.
2834
2835 Although technically you can either build test_kmod as a module or
2836 into the kernel we disallow building it into the kernel since
2837 it stress tests request_module() and this will very likely cause
2838 some issues by taking over precious threads available from other
2839 module load requests, ultimately this could be fatal.
2840
2841 To run tests run:
2842
2843 tools/testing/selftests/kmod/kmod.sh --help
2844
2845 If unsure, say N.
2846
e4dace36
FF
2847config TEST_DEBUG_VIRTUAL
2848 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2849 depends on DEBUG_VIRTUAL
2850 help
2851 Test the kernel's ability to detect incorrect calls to
2852 virt_to_phys() done against the non-linear part of the
2853 kernel's virtual address map.
2854
2855 If unsure, say N.
2856
ce76d938
AS
2857config TEST_MEMCAT_P
2858 tristate "Test memcat_p() helper function"
2859 help
2860 Test the memcat_p() helper for correctly merging two
2861 pointer arrays together.
2862
2863 If unsure, say N.
2864
0a020d41
JP
2865config TEST_OBJAGG
2866 tristate "Perform selftest on object aggreration manager"
2867 default n
2868 depends on OBJAGG
2869 help
2870 Enable this option to test object aggregation manager on boot
2871 (or module load).
2872
5015a300
AP
2873config TEST_MEMINIT
2874 tristate "Test heap/page initialization"
2875 help
2876 Test if the kernel is zero-initializing heap and page allocations.
2877 This can be useful to test init_on_alloc and init_on_free features.
2878
2879 If unsure, say N.
2880
b2ef9f5a
RC
2881config TEST_HMM
2882 tristate "Test HMM (Heterogeneous Memory Management)"
2883 depends on TRANSPARENT_HUGEPAGE
2884 depends on DEVICE_PRIVATE
2885 select HMM_MIRROR
2886 select MMU_NOTIFIER
2887 help
2888 This is a pseudo device driver solely for testing HMM.
2889 Say M here if you want to build the HMM test module.
2890 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2891
2892 If unsure, say N.
2893
e320d301
MWO
2894config TEST_FREE_PAGES
2895 tristate "Test freeing pages"
2896 help
2897 Test that a memory leak does not occur due to a race between
2898 freeing a block of pages and a speculative page reference.
2899 Loading this module is safe if your kernel has the bug fixed.
2900 If the bug is not fixed, it will leak gigabytes of memory and
2901 probably OOM your system.
2902
4185b3b9
PA
2903config TEST_FPU
2904 tristate "Test floating point operations in kernel space"
2905 depends on X86 && !KCOV_INSTRUMENT_ALL
2906 help
2907 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2908 which will trigger a sequence of floating point operations. This is used
2909 for self-testing floating point control register setting in
2910 kernel_fpu_begin().
2911
2912 If unsure, say N.
2913
1253b9b8
PM
2914config TEST_CLOCKSOURCE_WATCHDOG
2915 tristate "Test clocksource watchdog in kernel space"
2916 depends on CLOCKSOURCE_WATCHDOG
2917 help
2918 Enable this option to create a kernel module that will trigger
2919 a test of the clocksource watchdog. This module may be loaded
2920 via modprobe or insmod in which case it will run upon being
2921 loaded, or it may be built in, in which case it will run
2922 shortly after boot.
2923
2924 If unsure, say N.
2925
92f90d3b 2926config TEST_OBJPOOL
2927 tristate "Test module for correctness and stress of objpool"
2928 default n
2929 depends on m && DEBUG_KERNEL
2930 help
2931 This builds the "test_objpool" module that should be used for
2932 correctness verification and concurrent testings of objects
2933 allocation and reclamation.
2934
2935 If unsure, say N.
2936
d3deafaa 2937endif # RUNTIME_TESTING_MENU
cc3fa840 2938
dce44566
AK
2939config ARCH_USE_MEMTEST
2940 bool
2941 help
2942 An architecture should select this when it uses early_memtest()
2943 during boot process.
2944
cc3fa840
RD
2945config MEMTEST
2946 bool "Memtest"
dce44566 2947 depends on ARCH_USE_MEMTEST
a7f7f624 2948 help
cc3fa840 2949 This option adds a kernel parameter 'memtest', which allows memtest
dce44566 2950 to be set and executed.
cc3fa840
RD
2951 memtest=0, mean disabled; -- default
2952 memtest=1, mean do 1 test pattern;
2953 ...
2954 memtest=17, mean do 17 test patterns.
2955 If you are unsure how to answer this question, answer N.
2956
21266be9 2957
06ec64b8 2958
af9ca6f9
BB
2959config HYPERV_TESTING
2960 bool "Microsoft Hyper-V driver testing"
2961 default n
2962 depends on HYPERV && DEBUG_FS
2963 help
2964 Select this option to enable Hyper-V vmbus testing.
2965
045f6d79
CD
2966endmenu # "Kernel Testing and Coverage"
2967
2f7ab126
MO
2968menu "Rust hacking"
2969
2970config RUST_DEBUG_ASSERTIONS
2971 bool "Debug assertions"
2972 depends on RUST
2973 help
2974 Enables rustc's `-Cdebug-assertions` codegen option.
2975
2976 This flag lets you turn `cfg(debug_assertions)` conditional
2977 compilation on or off. This can be used to enable extra debugging
2978 code in development but not in production. For example, it controls
2979 the behavior of the standard library's `debug_assert!` macro.
2980
2981 Note that this will apply to all Rust code, including `core`.
2982
2983 If unsure, say N.
2984
2985config RUST_OVERFLOW_CHECKS
2986 bool "Overflow checks"
2987 default y
2988 depends on RUST
2989 help
2990 Enables rustc's `-Coverflow-checks` codegen option.
2991
2992 This flag allows you to control the behavior of runtime integer
2993 overflow. When overflow-checks are enabled, a Rust panic will occur
2994 on overflow.
2995
2996 Note that this will apply to all Rust code, including `core`.
2997
2998 If unsure, say Y.
2999
ecaa6ddf
GG
3000config RUST_BUILD_ASSERT_ALLOW
3001 bool "Allow unoptimized build-time assertions"
3002 depends on RUST
3003 help
3004 Controls how are `build_error!` and `build_assert!` handled during build.
3005
3006 If calls to them exist in the binary, it may indicate a violated invariant
3007 or that the optimizer failed to verify the invariant during compilation.
3008
3009 This should not happen, thus by default the build is aborted. However,
3010 as an escape hatch, you can choose Y here to ignore them during build
3011 and let the check be carried at runtime (with `panic!` being called if
3012 the check fails).
3013
3014 If unsure, say N.
3015
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MO
3016config RUST_KERNEL_DOCTESTS
3017 bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
3018 depends on RUST && KUNIT=y
3019 default KUNIT_ALL_TESTS
3020 help
3021 This builds the documentation tests of the `kernel` crate
3022 as KUnit tests.
3023
3024 For more information on KUnit and unit tests in general,
3025 please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
3026
3027 If unsure, say N.
3028
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3029endmenu # "Rust"
3030
06ec64b8 3031endmenu # Kernel hacking