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ec8f24b7 1# SPDX-License-Identifier: GPL-2.0-only
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2menu "Kernel hacking"
3
604ff0dc 4menu "printk and dmesg options"
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5
6config PRINTK_TIME
7 bool "Show timing information on printks"
d3b8b6e5 8 depends on PRINTK
1da177e4 9 help
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10 Selecting this option causes time stamps of the printk()
11 messages to be added to the output of the syslog() system
12 call and at the console.
13
14 The timestamp is always recorded internally, and exported
15 to /dev/kmsg. This flag just specifies if the timestamp should
16 be included, not that the timestamp is recorded.
17
18 The behavior is also controlled by the kernel command line
8c27ceff 19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
1da177e4 20
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21config PRINTK_CALLER
22 bool "Show caller information on printks"
23 depends on PRINTK
24 help
25 Selecting this option causes printk() to add a caller "thread id" (if
26 in task context) or a caller "processor id" (if not in task context)
27 to every message.
28
29 This option is intended for environments where multiple threads
30 concurrently call printk() for many times, for it is difficult to
31 interpret without knowing where these lines (or sometimes individual
32 line which was divided into multiple lines due to race) came from.
33
34 Since toggling after boot makes the code racy, currently there is
35 no option to enable/disable at the kernel command line parameter or
36 sysfs interface.
37
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38config STACKTRACE_BUILD_ID
39 bool "Show build ID information in stacktraces"
40 depends on PRINTK
41 help
42 Selecting this option adds build ID information for symbols in
43 stacktraces printed with the printk format '%p[SR]b'.
44
45 This option is intended for distros where debuginfo is not easily
46 accessible but can be downloaded given the build ID of the vmlinux or
47 kernel module where the function is located.
48
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49config CONSOLE_LOGLEVEL_DEFAULT
50 int "Default console loglevel (1-15)"
51 range 1 15
52 default "7"
53 help
54 Default loglevel to determine what will be printed on the console.
55
56 Setting a default here is equivalent to passing in loglevel=<x> in
57 the kernel bootargs. loglevel=<x> continues to override whatever
58 value is specified here as well.
59
50f4d9bd 60 Note: This does not affect the log level of un-prefixed printk()
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61 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
62 option.
63
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64config CONSOLE_LOGLEVEL_QUIET
65 int "quiet console loglevel (1-15)"
66 range 1 15
67 default "4"
68 help
69 loglevel to use when "quiet" is passed on the kernel commandline.
70
71 When "quiet" is passed on the kernel commandline this loglevel
72 will be used as the loglevel. IOW passing "quiet" will be the
73 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
74
42a9dc0b 75config MESSAGE_LOGLEVEL_DEFAULT
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76 int "Default message log level (1-7)"
77 range 1 7
78 default "4"
79 help
80 Default log level for printk statements with no specified priority.
81
82 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83 that are auditing their logs closely may want to set it to a lower
84 priority.
85
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86 Note: This does not affect what message level gets printed on the console
87 by default. To change that, use loglevel=<x> in the kernel bootargs,
88 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
89
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90config BOOT_PRINTK_DELAY
91 bool "Delay each boot printk message by N milliseconds"
92 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
93 help
94 This build option allows you to read kernel boot messages
95 by inserting a short delay after each one. The delay is
96 specified in milliseconds on the kernel command line,
97 using "boot_delay=N".
98
99 It is likely that you would also need to use "lpj=M" to preset
100 the "loops per jiffie" value.
101 See a previous boot log for the "lpj" value to use for your
102 system, and then set "lpj=M" before setting "boot_delay=N".
103 NOTE: Using this option may adversely affect SMP systems.
104 I.e., processors other than the first one may not boot up.
105 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106 what it believes to be lockup conditions.
107
108config DYNAMIC_DEBUG
109 bool "Enable dynamic printk() support"
110 default n
111 depends on PRINTK
239a5791 112 depends on (DEBUG_FS || PROC_FS)
ceabef7d 113 select DYNAMIC_DEBUG_CORE
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114 help
115
116 Compiles debug level messages into the kernel, which would not
117 otherwise be available at runtime. These messages can then be
118 enabled/disabled based on various levels of scope - per source file,
119 function, module, format string, and line number. This mechanism
120 implicitly compiles in all pr_debug() and dev_dbg() calls, which
121 enlarges the kernel text size by about 2%.
122
123 If a source file is compiled with DEBUG flag set, any
124 pr_debug() calls in it are enabled by default, but can be
125 disabled at runtime as below. Note that DEBUG flag is
126 turned on by many CONFIG_*DEBUG* options.
127
128 Usage:
129
130 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
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131 which is contained in the 'debugfs' filesystem or procfs.
132 Thus, the debugfs or procfs filesystem must first be mounted before
133 making use of this feature.
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134 We refer the control file as: <debugfs>/dynamic_debug/control. This
135 file contains a list of the debug statements that can be enabled. The
136 format for each line of the file is:
137
138 filename:lineno [module]function flags format
139
140 filename : source file of the debug statement
141 lineno : line number of the debug statement
142 module : module that contains the debug statement
143 function : function that contains the debug statement
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144 flags : '=p' means the line is turned 'on' for printing
145 format : the format used for the debug statement
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146
147 From a live system:
148
149 nullarbor:~ # cat <debugfs>/dynamic_debug/control
150 # filename:lineno [module]function flags format
151 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154
155 Example usage:
156
157 // enable the message at line 1603 of file svcsock.c
158 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159 <debugfs>/dynamic_debug/control
160
161 // enable all the messages in file svcsock.c
162 nullarbor:~ # echo -n 'file svcsock.c +p' >
163 <debugfs>/dynamic_debug/control
164
165 // enable all the messages in the NFS server module
166 nullarbor:~ # echo -n 'module nfsd +p' >
167 <debugfs>/dynamic_debug/control
168
169 // enable all 12 messages in the function svc_process()
170 nullarbor:~ # echo -n 'func svc_process +p' >
171 <debugfs>/dynamic_debug/control
172
173 // disable all 12 messages in the function svc_process()
174 nullarbor:~ # echo -n 'func svc_process -p' >
175 <debugfs>/dynamic_debug/control
176
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177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
178 information.
604ff0dc 179
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180config DYNAMIC_DEBUG_CORE
181 bool "Enable core function of dynamic debug support"
182 depends on PRINTK
183 depends on (DEBUG_FS || PROC_FS)
184 help
185 Enable core functional support of dynamic debug. It is useful
186 when you want to tie dynamic debug to your kernel modules with
187 DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188 the case of embedded system where the kernel image size is
189 sensitive for people.
190
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191config SYMBOLIC_ERRNAME
192 bool "Support symbolic error names in printf"
193 default y if PRINTK
194 help
195 If you say Y here, the kernel's printf implementation will
196 be able to print symbolic error names such as ENOSPC instead
197 of the number 28. It makes the kernel image slightly larger
198 (about 3KB), but can make the kernel logs easier to read.
199
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200config DEBUG_BUGVERBOSE
201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
203 default y
204 help
205 Say Y here to make BUG() panics output the file name and line number
206 of the BUG call as well as the EIP and oops trace. This aids
207 debugging but costs about 70-100K of memory.
208
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209endmenu # "printk and dmesg options"
210
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211config DEBUG_KERNEL
212 bool "Kernel debugging"
213 help
214 Say Y here if you are developing drivers or trying to debug and
215 identify kernel problems.
216
217config DEBUG_MISC
218 bool "Miscellaneous debug code"
219 default DEBUG_KERNEL
220 depends on DEBUG_KERNEL
221 help
222 Say Y here if you need to enable miscellaneous debug code that should
223 be under a more specific debug option but isn't.
224
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225menu "Compile-time checks and compiler options"
226
227config DEBUG_INFO
f9b3cd24 228 bool
6dfc0665 229 help
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230 A kernel debug info option other than "None" has been selected
231 in the "Debug information" choice below, indicating that debug
232 information will be generated for build targets.
233
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234# Clang is known to generate .{s,u}leb128 with symbol deltas with DWARF5, which
235# some targets may not support: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
236config AS_HAS_NON_CONST_LEB128
237 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
238
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239choice
240 prompt "Debug information"
241 depends on DEBUG_KERNEL
242 help
243 Selecting something other than "None" results in a kernel image
244 that will include debugging info resulting in a larger kernel image.
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245 This adds debug symbols to the kernel and modules (gcc -g), and
246 is needed if you intend to use kernel crashdump or binary object
247 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
6dfc0665 248
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249 Choose which version of DWARF debug info to emit. If unsure,
250 select "Toolchain default".
251
252config DEBUG_INFO_NONE
253 bool "Disable debug information"
254 help
255 Do not build the kernel with debugging information, which will
256 result in a faster and smaller build.
257
258config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
259 bool "Rely on the toolchain's implicit default DWARF version"
260 select DEBUG_INFO
0a6de78c 261 depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
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262 help
263 The implicit default version of DWARF debug info produced by a
264 toolchain changes over time.
265
266 This can break consumers of the debug info that haven't upgraded to
267 support newer revisions, and prevent testing newer versions, but
268 those should be less common scenarios.
269
270config DEBUG_INFO_DWARF4
271 bool "Generate DWARF Version 4 debuginfo"
272 select DEBUG_INFO
4f001a21 273 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
f9b3cd24 274 help
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275 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
276 if using clang without clang's integrated assembler, and gdb 7.0+.
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277
278 If you have consumers of DWARF debug info that are not ready for
279 newer revisions of DWARF, you may wish to choose this or have your
280 config select this.
281
282config DEBUG_INFO_DWARF5
283 bool "Generate DWARF Version 5 debuginfo"
284 select DEBUG_INFO
0a6de78c 285 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
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286 help
287 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
288 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
289 draft features until 7.0), and gdb 8.0+.
290
291 Changes to the structure of debug info in Version 5 allow for around
292 15-18% savings in resulting image and debug info section sizes as
293 compared to DWARF Version 4. DWARF Version 5 standardizes previous
294 extensions such as accelerators for symbol indexing and the format
295 for fission (.dwo/.dwp) files. Users may not want to select this
296 config if they rely on tooling that has not yet been updated to
297 support DWARF Version 5.
298
299endchoice # "Debug information"
6dfc0665 300
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301if DEBUG_INFO
302
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303config DEBUG_INFO_REDUCED
304 bool "Reduce debugging information"
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305 help
306 If you say Y here gcc is instructed to generate less debugging
307 information for structure types. This means that tools that
308 need full debugging information (like kgdb or systemtap) won't
309 be happy. But if you merely need debugging information to
310 resolve line numbers there is no loss. Advantage is that
311 build directory object sizes shrink dramatically over a full
312 DEBUG_INFO build and compile times are reduced too.
313 Only works with newer gcc versions.
314
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315choice
316 prompt "Compressed Debug information"
317 help
318 Compress the resulting debug info. Results in smaller debug info sections,
319 but requires that consumers are able to decompress the results.
320
321 If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
322
323config DEBUG_INFO_COMPRESSED_NONE
324 bool "Don't compress debug information"
325 help
326 Don't compress debug info sections.
327
328config DEBUG_INFO_COMPRESSED_ZLIB
329 bool "Compress debugging information with zlib"
10e68b02 330 depends on $(cc-option,-gz=zlib)
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331 depends on $(ld-option,--compress-debug-sections=zlib)
332 help
333 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
334 5.0+, binutils 2.26+, and zlib.
335
336 Users of dpkg-deb via scripts/package/builddeb may find an increase in
337 size of their debug .deb packages with this config set, due to the
338 debug info being compressed with zlib, then the object files being
339 recompressed with a different compression scheme. But this is still
340 preferable to setting $KDEB_COMPRESS to "none" which would be even
341 larger.
342
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343config DEBUG_INFO_COMPRESSED_ZSTD
344 bool "Compress debugging information with zstd"
345 depends on $(cc-option,-gz=zstd)
346 depends on $(ld-option,--compress-debug-sections=zstd)
347 help
348 Compress the debug information using zstd. This may provide better
349 compression than zlib, for about the same time costs, but requires newer
350 toolchain support. Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
351 zstd.
352
353endchoice # "Compressed Debug information"
354
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355config DEBUG_INFO_SPLIT
356 bool "Produce split debuginfo in .dwo files"
9d937444 357 depends on $(cc-option,-gsplit-dwarf)
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358 # RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC
359 # prior to 12.x:
360 # https://github.com/llvm/llvm-project/issues/56642
361 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090
362 depends on !RISCV || GCC_VERSION >= 120000
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363 help
364 Generate debug info into separate .dwo files. This significantly
365 reduces the build directory size for builds with DEBUG_INFO,
366 because it stores the information only once on disk in .dwo
367 files instead of multiple times in object files and executables.
368 In addition the debug information is also compressed.
369
370 Requires recent gcc (4.7+) and recent gdb/binutils.
371 Any tool that packages or reads debug information would need
372 to know about the .dwo files and include them.
373 Incompatible with older versions of ccache.
374
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375config DEBUG_INFO_BTF
376 bool "Generate BTF typeinfo"
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377 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
378 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
d9847eb8 379 depends on BPF_SYSCALL
52deda95 380 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
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381 help
382 Generate deduplicated BTF type information from DWARF debug info.
383 Turning this on expects presence of pahole tool, which will convert
384 DWARF type info into equivalent deduplicated BTF type info.
385
5f9ae91f 386config PAHOLE_HAS_SPLIT_BTF
6323c813 387 def_bool PAHOLE_VERSION >= 119
5f9ae91f 388
7472d5a6 389config PAHOLE_HAS_BTF_TAG
6323c813 390 def_bool PAHOLE_VERSION >= 123
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391 depends on CC_IS_CLANG
392 help
393 Decide whether pahole emits btf_tag attributes (btf_type_tag and
394 btf_decl_tag) or not. Currently only clang compiler implements
395 these attributes, so make the config depend on CC_IS_CLANG.
5f9ae91f 396
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397config PAHOLE_HAS_LANG_EXCLUDE
398 def_bool PAHOLE_VERSION >= 124
399 help
400 Support for the --lang_exclude flag which makes pahole exclude
401 compilation units from the supplied language. Used in Kbuild to
402 omit Rust CUs which are not supported in version 1.24 of pahole,
403 otherwise it would emit malformed kernel and module binaries when
404 using DEBUG_INFO_BTF_MODULES.
405
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406config DEBUG_INFO_BTF_MODULES
407 def_bool y
408 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
409 help
410 Generate compact split BTF type information for kernel modules.
411
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412config MODULE_ALLOW_BTF_MISMATCH
413 bool "Allow loading modules with non-matching BTF type info"
414 depends on DEBUG_INFO_BTF_MODULES
415 help
416 For modules whose split BTF does not match vmlinux, load without
417 BTF rather than refusing to load. The default behavior with
418 module BTF enabled is to reject modules with such mismatches;
419 this option will still load module BTF where possible but ignore
420 it when a mismatch is found.
421
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422config GDB_SCRIPTS
423 bool "Provide GDB scripts for kernel debugging"
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424 help
425 This creates the required links to GDB helper scripts in the
426 build directory. If you load vmlinux into gdb, the helper
427 scripts will be automatically imported by gdb as well, and
428 additional functions are available to analyze a Linux kernel
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429 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
430 for further details.
3ee7b3fa 431
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432endif # DEBUG_INFO
433
35bb5b1e 434config FRAME_WARN
a83e4ca2 435 int "Warn for stack frames larger than"
35bb5b1e 436 range 0 8192
ac66998d 437 default 0 if KMSAN
0e07f663 438 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
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439 default 2048 if PARISC
440 default 1536 if (!64BIT && XTENSA)
152fe65f 441 default 1280 if KASAN && !64BIT
8d192bec 442 default 1024 if !64BIT
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443 default 2048 if 64BIT
444 help
921757bc 445 Tell the compiler to warn at build time for stack frames larger than this.
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446 Setting this too low will cause a lot of warnings.
447 Setting it to 0 disables the warning.
35bb5b1e 448
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449config STRIP_ASM_SYMS
450 bool "Strip assembler-generated symbols during link"
451 default n
452 help
453 Strip internal assembler-generated symbols during a link (symbols
454 that look like '.Lxxx') so they don't pollute the output of
455 get_wchan() and suchlike.
456
1873e870 457config READABLE_ASM
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458 bool "Generate readable assembler code"
459 depends on DEBUG_KERNEL
7d73c3e9 460 depends on CC_IS_GCC
bf4735a4 461 help
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462 Disable some compiler optimizations that tend to generate human unreadable
463 assembler output. This may make the kernel slightly slower, but it helps
464 to keep kernel developers who have to stare a lot at assembler listings
465 sane.
bf4735a4 466
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467config HEADERS_INSTALL
468 bool "Install uapi headers to usr/include"
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469 depends on !UML
470 help
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471 This option will install uapi headers (headers exported to user-space)
472 into the usr/include directory for use during the kernel build.
473 This is unneeded for building the kernel itself, but needed for some
474 user-space program samples. It is also needed by some features such
475 as uapi header sanity checks.
476
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477config DEBUG_SECTION_MISMATCH
478 bool "Enable full Section mismatch analysis"
7d73c3e9 479 depends on CC_IS_GCC
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480 help
481 The section mismatch analysis checks if there are illegal
482 references from one section to another section.
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483 During linktime or runtime, some sections are dropped;
484 any use of code/data previously in these sections would
91341d4b 485 most likely result in an oops.
e809ab01 486 In the code, functions and variables are annotated with
0db0628d 487 __init,, etc. (see the full list in include/linux/init.h),
d6fbfa4f 488 which results in the code/data being placed in specific sections.
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489 The section mismatch analysis is always performed after a full
490 kernel build, and enabling this option causes the following
b7dca6dd 491 additional step to occur:
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492 - Add the option -fno-inline-functions-called-once to gcc commands.
493 When inlining a function annotated with __init in a non-init
494 function, we would lose the section information and thus
91341d4b 495 the analysis would not catch the illegal reference.
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496 This option tells gcc to inline less (but it does result in
497 a larger kernel).
91341d4b 498
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499config SECTION_MISMATCH_WARN_ONLY
500 bool "Make section mismatch errors non-fatal"
501 default y
502 help
503 If you say N here, the build process will fail if there are any
504 section mismatch, instead of just throwing warnings.
505
506 If unsure, say Y.
507
cf536e18 508config DEBUG_FORCE_FUNCTION_ALIGN_64B
1bf18da6 509 bool "Force all function address 64B aligned"
3ed8513c 510 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390)
d49a0626 511 select FUNCTION_ALIGNMENT_64B
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512 help
513 There are cases that a commit from one domain changes the function
514 address alignment of other domains, and cause magic performance
515 bump (regression or improvement). Enable this option will help to
516 verify if the bump is caused by function alignment changes, while
517 it will slightly increase the kernel size and affect icache usage.
518
519 It is mainly for debug and performance tuning use.
520
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521#
522# Select this config option from the architecture Kconfig, if it
523# is preferred to always offer frame pointers as a config
524# option on the architecture (regardless of KERNEL_DEBUG):
525#
526config ARCH_WANT_FRAME_POINTERS
527 bool
f346f4b3 528
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529config FRAME_POINTER
530 bool "Compile the kernel with frame pointers"
a687a533 531 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
6dfc0665 532 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
a304e1b8 533 help
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534 If you say Y here the resulting kernel image will be slightly
535 larger and slower, but it gives very useful debugging information
536 in case of kernel bugs. (precise oopses/stacktraces/warnings)
a304e1b8 537
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538config OBJTOOL
539 bool
540
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541config STACK_VALIDATION
542 bool "Compile-time stack metadata validation"
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543 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
544 select OBJTOOL
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545 default n
546 help
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547 Validate frame pointer rules at compile-time. This helps ensure that
548 runtime stack traces are more reliable.
ee9f8fce 549
b9ab5ebb 550 For more information, see
d6a21f2d 551 tools/objtool/Documentation/objtool.txt.
b9ab5ebb 552
0f620cef 553config NOINSTR_VALIDATION
6804c1af 554 bool
489e355b 555 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
03f16cd0 556 select OBJTOOL
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557 default y
558
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559config VMLINUX_MAP
560 bool "Generate vmlinux.map file when linking"
561 depends on EXPERT
562 help
563 Selecting this option will pass "-Map=vmlinux.map" to ld
564 when linking vmlinux. That file can be useful for verifying
565 and debugging magic section games, and for seeing which
566 pieces of code get eliminated with
567 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
568
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569config DEBUG_FORCE_WEAK_PER_CPU
570 bool "Force weak per-cpu definitions"
571 depends on DEBUG_KERNEL
8446f1d3 572 help
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573 s390 and alpha require percpu variables in modules to be
574 defined weak to work around addressing range issue which
575 puts the following two restrictions on percpu variable
576 definitions.
8446f1d3 577
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578 1. percpu symbols must be unique whether static or not
579 2. percpu variables can't be defined inside a function
8446f1d3 580
6dfc0665
DH
581 To ensure that generic code follows the above rules, this
582 option forces all percpu variables to be defined as weak.
5f329089 583
6dfc0665 584endmenu # "Compiler options"
8446f1d3 585
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CD
586menu "Generic Kernel Debugging Instruments"
587
6dfc0665
DH
588config MAGIC_SYSRQ
589 bool "Magic SysRq key"
590 depends on !UML
591 help
592 If you say Y here, you will have some control over the system even
593 if the system crashes for example during kernel debugging (e.g., you
594 will be able to flush the buffer cache to disk, reboot the system
595 immediately or dump some status information). This is accomplished
596 by pressing various keys while holding SysRq (Alt+PrintScreen). It
597 also works on a serial console (on PC hardware at least), if you
598 send a BREAK and then within 5 seconds a command keypress. The
f8998c22
HH
599 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
600 Don't say Y unless you really know what this hack does.
8446f1d3 601
8eaede49
BH
602config MAGIC_SYSRQ_DEFAULT_ENABLE
603 hex "Enable magic SysRq key functions by default"
604 depends on MAGIC_SYSRQ
605 default 0x1
606 help
607 Specifies which SysRq key functions are enabled by default.
608 This may be set to 1 or 0 to enable or disable them all, or
f8998c22 609 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
8eaede49 610
732dbf3a
FF
611config MAGIC_SYSRQ_SERIAL
612 bool "Enable magic SysRq key over serial"
613 depends on MAGIC_SYSRQ
614 default y
615 help
616 Many embedded boards have a disconnected TTL level serial which can
617 generate some garbage that can lead to spurious false sysrq detects.
618 This option allows you to decide whether you want to enable the
619 magic SysRq key.
620
68af4317
DS
621config MAGIC_SYSRQ_SERIAL_SEQUENCE
622 string "Char sequence that enables magic SysRq over serial"
623 depends on MAGIC_SYSRQ_SERIAL
624 default ""
625 help
626 Specifies a sequence of characters that can follow BREAK to enable
627 SysRq on a serial console.
628
d3394b3d
DS
629 If unsure, leave an empty string and the option will not be enabled.
630
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CD
631config DEBUG_FS
632 bool "Debug Filesystem"
633 help
634 debugfs is a virtual file system that kernel developers use to put
635 debugging files into. Enable this option to be able to read and
636 write to these files.
637
638 For detailed documentation on the debugfs API, see
639 Documentation/filesystems/.
640
641 If unsure, say N.
642
a24c6f7b
PE
643choice
644 prompt "Debugfs default access"
645 depends on DEBUG_FS
646 default DEBUG_FS_ALLOW_ALL
647 help
648 This selects the default access restrictions for debugfs.
649 It can be overridden with kernel command line option
650 debugfs=[on,no-mount,off]. The restrictions apply for API access
651 and filesystem registration.
652
653config DEBUG_FS_ALLOW_ALL
654 bool "Access normal"
655 help
656 No restrictions apply. Both API and filesystem registration
657 is on. This is the normal default operation.
658
659config DEBUG_FS_DISALLOW_MOUNT
660 bool "Do not register debugfs as filesystem"
661 help
662 The API is open but filesystem is not loaded. Clients can still do
663 their work and read with debug tools that do not need
664 debugfs filesystem.
665
666config DEBUG_FS_ALLOW_NONE
667 bool "No access"
668 help
669 Access is off. Clients get -PERM when trying to create nodes in
670 debugfs tree and debugfs is not registered as a filesystem.
671 Client can then back-off or continue without debugfs access.
672
673endchoice
674
6210b640 675source "lib/Kconfig.kgdb"
6210b640 676source "lib/Kconfig.ubsan"
2645d432 677source "lib/Kconfig.kcsan"
6210b640
CD
678
679endmenu
680
4d92b95f
ED
681menu "Networking Debugging"
682
683source "net/Kconfig.debug"
684
685endmenu # "Networking Debugging"
c66d7a27 686
0610c8a8 687menu "Memory Debugging"
fef2c9bc 688
8636a1f9 689source "mm/Kconfig.debug"
fef2c9bc 690
0610c8a8
DH
691config DEBUG_OBJECTS
692 bool "Debug object operations"
693 depends on DEBUG_KERNEL
9c44bc03 694 help
0610c8a8
DH
695 If you say Y here, additional code will be inserted into the
696 kernel to track the life time of various objects and validate
697 the operations on those objects.
9c44bc03 698
0610c8a8
DH
699config DEBUG_OBJECTS_SELFTEST
700 bool "Debug objects selftest"
701 depends on DEBUG_OBJECTS
702 help
703 This enables the selftest of the object debug code.
9c44bc03 704
0610c8a8
DH
705config DEBUG_OBJECTS_FREE
706 bool "Debug objects in freed memory"
707 depends on DEBUG_OBJECTS
708 help
709 This enables checks whether a k/v free operation frees an area
710 which contains an object which has not been deactivated
711 properly. This can make kmalloc/kfree-intensive workloads
712 much slower.
3ac7fe5a 713
c6f3a97f
TG
714config DEBUG_OBJECTS_TIMERS
715 bool "Debug timer objects"
716 depends on DEBUG_OBJECTS
717 help
718 If you say Y here, additional code will be inserted into the
719 timer routines to track the life time of timer objects and
720 validate the timer operations.
721
dc186ad7
TG
722config DEBUG_OBJECTS_WORK
723 bool "Debug work objects"
724 depends on DEBUG_OBJECTS
725 help
726 If you say Y here, additional code will be inserted into the
727 work queue routines to track the life time of work objects and
728 validate the work operations.
729
551d55a9
MD
730config DEBUG_OBJECTS_RCU_HEAD
731 bool "Debug RCU callbacks objects"
fc2ecf7e 732 depends on DEBUG_OBJECTS
551d55a9
MD
733 help
734 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
735
e2852ae8
TH
736config DEBUG_OBJECTS_PERCPU_COUNTER
737 bool "Debug percpu counter objects"
738 depends on DEBUG_OBJECTS
739 help
740 If you say Y here, additional code will be inserted into the
741 percpu counter routines to track the life time of percpu counter
742 objects and validate the percpu counter operations.
743
3ae70205
IM
744config DEBUG_OBJECTS_ENABLE_DEFAULT
745 int "debug_objects bootup default value (0-1)"
68d4b3df
KK
746 range 0 1
747 default "1"
748 depends on DEBUG_OBJECTS
749 help
750 Debug objects boot parameter default value
3ae70205 751
5035ebc6 752config SHRINKER_DEBUG
5035ebc6
RG
753 bool "Enable shrinker debugging support"
754 depends on DEBUG_FS
755 help
756 Say Y to enable the shrinker debugfs interface which provides
757 visibility into the kernel memory shrinkers subsystem.
758 Disable it to avoid an extra memory footprint.
759
0610c8a8
DH
760config DEBUG_STACK_USAGE
761 bool "Stack utilization instrumentation"
cf8e8658 762 depends on DEBUG_KERNEL
0610c8a8
DH
763 help
764 Enables the display of the minimum amount of free stack which each
765 task has ever had available in the sysrq-T and sysrq-P debug output.
766
767 This option will slow down process creation somewhat.
768
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CD
769config SCHED_STACK_END_CHECK
770 bool "Detect stack corruption on calls to schedule()"
771 depends on DEBUG_KERNEL
772 default n
773 help
774 This option checks for a stack overrun on calls to schedule().
775 If the stack end location is found to be over written always panic as
776 the content of the corrupted region can no longer be trusted.
777 This is to ensure no erroneous behaviour occurs which could result in
778 data corruption or a sporadic crash at a later stage once the region
779 is examined. The runtime overhead introduced is minimal.
780
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AK
781config ARCH_HAS_DEBUG_VM_PGTABLE
782 bool
783 help
784 An architecture should select this when it can successfully
785 build and run DEBUG_VM_PGTABLE.
786
a738e9ba
TG
787config DEBUG_VM_IRQSOFF
788 def_bool DEBUG_VM && !PREEMPT_RT
789
0610c8a8
DH
790config DEBUG_VM
791 bool "Debug VM"
792 depends on DEBUG_KERNEL
793 help
794 Enable this to turn on extended checks in the virtual-memory system
68d4b3df 795 that may impact performance.
0610c8a8
DH
796
797 If unsure, say N.
798
2655421a
NP
799config DEBUG_VM_SHOOT_LAZIES
800 bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
801 depends on DEBUG_VM
802 depends on MMU_LAZY_TLB_SHOOTDOWN
803 help
804 Enable additional IPIs that ensure lazy tlb mm references are removed
805 before the mm is freed.
806
807 If unsure, say N.
808
54a611b6
LH
809config DEBUG_VM_MAPLE_TREE
810 bool "Debug VM maple trees"
4f115147 811 depends on DEBUG_VM
54a611b6 812 select DEBUG_MAPLE_TREE
4f115147 813 help
54a611b6 814 Enable VM maple tree debugging information and extra validations.
4f115147
DB
815
816 If unsure, say N.
817
0610c8a8
DH
818config DEBUG_VM_RB
819 bool "Debug VM red-black trees"
820 depends on DEBUG_VM
821 help
a663dad6 822 Enable VM red-black tree debugging information and extra validations.
0610c8a8
DH
823
824 If unsure, say N.
825
95ad9755
KS
826config DEBUG_VM_PGFLAGS
827 bool "Debug page-flags operations"
828 depends on DEBUG_VM
829 help
830 Enables extra validation on page flags operations.
831
832 If unsure, say N.
833
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AK
834config DEBUG_VM_PGTABLE
835 bool "Debug arch page table for semantics compliance"
836 depends on MMU
837 depends on ARCH_HAS_DEBUG_VM_PGTABLE
838 default y if DEBUG_VM
839 help
840 This option provides a debug method which can be used to test
841 architecture page table helper functions on various platforms in
842 verifying if they comply with expected generic MM semantics. This
843 will help architecture code in making sure that any changes or
844 new additions of these helpers still conform to expected
845 semantics of the generic MM. Platforms will have to opt in for
846 this through ARCH_HAS_DEBUG_VM_PGTABLE.
847
848 If unsure, say N.
849
fa5b6ec9
LA
850config ARCH_HAS_DEBUG_VIRTUAL
851 bool
852
0610c8a8
DH
853config DEBUG_VIRTUAL
854 bool "Debug VM translations"
fa5b6ec9 855 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
0610c8a8
DH
856 help
857 Enable some costly sanity checks in virtual to page code. This can
858 catch mistakes with virt_to_page() and friends.
859
860 If unsure, say N.
861
862config DEBUG_NOMMU_REGIONS
863 bool "Debug the global anon/private NOMMU mapping region tree"
864 depends on DEBUG_KERNEL && !MMU
865 help
866 This option causes the global tree of anonymous and private mapping
867 regions to be regularly checked for invalid topology.
868
869config DEBUG_MEMORY_INIT
870 bool "Debug memory initialisation" if EXPERT
871 default !EXPERT
872 help
873 Enable this for additional checks during memory initialisation.
874 The sanity checks verify aspects of the VM such as the memory model
875 and other information provided by the architecture. Verbose
876 information will be printed at KERN_DEBUG loglevel depending
877 on the mminit_loglevel= command-line option.
878
879 If unsure, say Y
880
881config MEMORY_NOTIFIER_ERROR_INJECT
882 tristate "Memory hotplug notifier error injection module"
50f9481e 883 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
0610c8a8
DH
884 help
885 This option provides the ability to inject artificial errors to
886 memory hotplug notifier chain callbacks. It is controlled through
887 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
888
889 If the notifier call chain should be failed with some events
890 notified, write the error code to "actions/<notifier event>/error".
891
892 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
893
894 # cd /sys/kernel/debug/notifier-error-inject/memory
895 # echo -12 > actions/MEM_GOING_OFFLINE/error
896 # echo offline > /sys/devices/system/memory/memoryXXX/state
897 bash: echo: write error: Cannot allocate memory
898
899 To compile this code as a module, choose M here: the module will
900 be called memory-notifier-error-inject.
901
902 If unsure, say N.
903
904config DEBUG_PER_CPU_MAPS
905 bool "Debug access to per_cpu maps"
906 depends on DEBUG_KERNEL
907 depends on SMP
908 help
909 Say Y to verify that the per_cpu map being accessed has
910 been set up. This adds a fair amount of code to kernel memory
911 and decreases performance.
912
913 Say N if unsure.
914
6e799cb6
TG
915config DEBUG_KMAP_LOCAL
916 bool "Debug kmap_local temporary mappings"
917 depends on DEBUG_KERNEL && KMAP_LOCAL
918 help
919 This option enables additional error checking for the kmap_local
920 infrastructure. Disable for production use.
921
0e91a0c6
TG
922config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
923 bool
924
925config DEBUG_KMAP_LOCAL_FORCE_MAP
926 bool "Enforce kmap_local temporary mappings"
927 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
928 select KMAP_LOCAL
929 select DEBUG_KMAP_LOCAL
930 help
931 This option enforces temporary mappings through the kmap_local
932 mechanism for non-highmem pages and on non-highmem systems.
933 Disable this for production systems!
934
0610c8a8
DH
935config DEBUG_HIGHMEM
936 bool "Highmem debugging"
937 depends on DEBUG_KERNEL && HIGHMEM
0e91a0c6 938 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
6e799cb6 939 select DEBUG_KMAP_LOCAL
0610c8a8 940 help
b1357c9f
GU
941 This option enables additional error checking for high memory
942 systems. Disable for production systems.
0610c8a8
DH
943
944config HAVE_DEBUG_STACKOVERFLOW
945 bool
946
947config DEBUG_STACKOVERFLOW
948 bool "Check for stack overflows"
949 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
a7f7f624 950 help
0610c8a8 951 Say Y here if you want to check for overflows of kernel, IRQ
edb0ec07 952 and exception stacks (if your architecture uses them). This
0610c8a8
DH
953 option will show detailed messages if free stack space drops
954 below a certain limit.
955
956 These kinds of bugs usually occur when call-chains in the
957 kernel get too deep, especially when interrupts are
958 involved.
959
960 Use this in cases where you see apparently random memory
961 corruption, especially if it appears in 'struct thread_info'
962
963 If in doubt, say "N".
964
0b24becc 965source "lib/Kconfig.kasan"
0ce20dd8 966source "lib/Kconfig.kfence"
f80be457 967source "lib/Kconfig.kmsan"
0b24becc 968
0610c8a8
DH
969endmenu # "Memory Debugging"
970
a304e1b8
DW
971config DEBUG_SHIRQ
972 bool "Debug shared IRQ handlers"
0244ad00 973 depends on DEBUG_KERNEL
a304e1b8 974 help
0a2fae2a
WS
975 Enable this to generate a spurious interrupt just before a shared
976 interrupt handler is deregistered (generating one when registering
977 is currently disabled). Drivers need to handle this correctly. Some
978 don't and need to be caught.
a304e1b8 979
f43a289d
CD
980menu "Debug Oops, Lockups and Hangs"
981
982config PANIC_ON_OOPS
983 bool "Panic on Oops"
984 help
985 Say Y here to enable the kernel to panic when it oopses. This
986 has the same effect as setting oops=panic on the kernel command
987 line.
988
989 This feature is useful to ensure that the kernel does not do
990 anything erroneous after an oops which could result in data
991 corruption or other issues.
992
993 Say N if unsure.
994
995config PANIC_ON_OOPS_VALUE
996 int
997 range 0 1
998 default 0 if !PANIC_ON_OOPS
999 default 1 if PANIC_ON_OOPS
1000
1001config PANIC_TIMEOUT
1002 int "panic timeout"
1003 default 0
1004 help
9d5b134f 1005 Set the timeout value (in seconds) until a reboot occurs when
f43a289d
CD
1006 the kernel panics. If n = 0, then we wait forever. A timeout
1007 value n > 0 will wait n seconds before rebooting, while a timeout
1008 value n < 0 will reboot immediately.
92aef8fb 1009
58687acb 1010config LOCKUP_DETECTOR
05a4a952
NP
1011 bool
1012
1013config SOFTLOCKUP_DETECTOR
1014 bool "Detect Soft Lockups"
dea20a3f 1015 depends on DEBUG_KERNEL && !S390
05a4a952 1016 select LOCKUP_DETECTOR
8446f1d3 1017 help
58687acb 1018 Say Y here to enable the kernel to act as a watchdog to detect
05a4a952 1019 soft lockups.
58687acb
DZ
1020
1021 Softlockups are bugs that cause the kernel to loop in kernel
5f329089 1022 mode for more than 20 seconds, without giving other tasks a
58687acb
DZ
1023 chance to run. The current stack trace is displayed upon
1024 detection and the system will stay locked up.
8446f1d3 1025
5f00ae0d
RD
1026config BOOTPARAM_SOFTLOCKUP_PANIC
1027 bool "Panic (Reboot) On Soft Lockups"
1028 depends on SOFTLOCKUP_DETECTOR
1029 help
1030 Say Y here to enable the kernel to panic on "soft lockups",
1031 which are bugs that cause the kernel to loop in kernel
1032 mode for more than 20 seconds (configurable using the watchdog_thresh
1033 sysctl), without giving other tasks a chance to run.
1034
1035 The panic can be used in combination with panic_timeout,
1036 to cause the system to reboot automatically after a
1037 lockup has been detected. This feature is useful for
1038 high-availability systems that have uptime guarantees and
1039 where a lockup must be resolved ASAP.
1040
1041 Say N if unsure.
1042
1356d0b9 1043config HAVE_HARDLOCKUP_DETECTOR_BUDDY
05a4a952 1044 bool
1356d0b9
PM
1045 depends on SMP
1046 default y
05a4a952 1047
7edaeb68 1048#
1356d0b9
PM
1049# Global switch whether to build a hardlockup detector at all. It is available
1050# only when the architecture supports at least one implementation. There are
1051# two exceptions. The hardlockup detector is never enabled on:
7edaeb68 1052#
1356d0b9 1053# s390: it reported many false positives there
05a4a952 1054#
1356d0b9
PM
1055# sparc64: has a custom implementation which is not using the common
1056# hardlockup command line options and sysctl interface.
05a4a952
NP
1057#
1058config HARDLOCKUP_DETECTOR
1059 bool "Detect Hard Lockups"
47f4cb43 1060 depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
a5fcc236 1061 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
1356d0b9
PM
1062 imply HARDLOCKUP_DETECTOR_PERF
1063 imply HARDLOCKUP_DETECTOR_BUDDY
7ca8fe94 1064 imply HARDLOCKUP_DETECTOR_ARCH
05a4a952 1065 select LOCKUP_DETECTOR
4917a25f 1066
05a4a952
NP
1067 help
1068 Say Y here to enable the kernel to act as a watchdog to detect
1069 hard lockups.
1070
58687acb 1071 Hardlockups are bugs that cause the CPU to loop in kernel mode
5f329089 1072 for more than 10 seconds, without letting other interrupts have a
58687acb
DZ
1073 chance to run. The current stack trace is displayed upon detection
1074 and the system will stay locked up.
8446f1d3 1075
1356d0b9
PM
1076#
1077# Note that arch-specific variants are always preferred.
1078#
4917a25f
PM
1079config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1080 bool "Prefer the buddy CPU hardlockup detector"
1356d0b9
PM
1081 depends on HARDLOCKUP_DETECTOR
1082 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
a8992d8a 1083 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
4917a25f
PM
1084 help
1085 Say Y here to prefer the buddy hardlockup detector over the perf one.
1086
1087 With the buddy detector, each CPU uses its softlockup hrtimer
1088 to check that the next CPU is processing hrtimer interrupts by
1089 verifying that a counter is increasing.
1090
1091 This hardlockup detector is useful on systems that don't have
1092 an arch-specific hardlockup detector or if resources needed
1093 for the hardlockup detector are better used for other things.
05a4a952 1094
1f423c90
DA
1095config HARDLOCKUP_DETECTOR_PERF
1096 bool
1356d0b9
PM
1097 depends on HARDLOCKUP_DETECTOR
1098 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
a5fcc236 1099 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1f423c90
DA
1100 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1101
1102config HARDLOCKUP_DETECTOR_BUDDY
1103 bool
1356d0b9
PM
1104 depends on HARDLOCKUP_DETECTOR
1105 depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1106 depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
a5fcc236 1107 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1f423c90
DA
1108 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1109
7ca8fe94
PM
1110config HARDLOCKUP_DETECTOR_ARCH
1111 bool
1112 depends on HARDLOCKUP_DETECTOR
1113 depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1114 help
1115 The arch-specific implementation of the hardlockup detector will
1116 be used.
1117
1356d0b9 1118#
4917a25f
PM
1119# Both the "perf" and "buddy" hardlockup detectors count hrtimer
1120# interrupts. This config enables functions managing this common code.
1356d0b9 1121#
4917a25f
PM
1122config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1123 bool
1124 select SOFTLOCKUP_DETECTOR
1125
7edaeb68
TG
1126#
1127# Enables a timestamp based low pass filter to compensate for perf based
1128# hard lockup detection which runs too fast due to turbo modes.
1129#
1130config HARDLOCKUP_CHECK_TIMESTAMP
1131 bool
1132
fef2c9bc
DZ
1133config BOOTPARAM_HARDLOCKUP_PANIC
1134 bool "Panic (Reboot) On Hard Lockups"
8f1f66ed 1135 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
1136 help
1137 Say Y here to enable the kernel to panic on "hard lockups",
1138 which are bugs that cause the kernel to loop in kernel
5f329089
FLVC
1139 mode with interrupts disabled for more than 10 seconds (configurable
1140 using the watchdog_thresh sysctl).
fef2c9bc
DZ
1141
1142 Say N if unsure.
1143
e162b39a
MSB
1144config DETECT_HUNG_TASK
1145 bool "Detect Hung Tasks"
1146 depends on DEBUG_KERNEL
05a4a952 1147 default SOFTLOCKUP_DETECTOR
e162b39a 1148 help
0610c8a8
DH
1149 Say Y here to enable the kernel to detect "hung tasks",
1150 which are bugs that cause the task to be stuck in
96b03ab8 1151 uninterruptible "D" state indefinitely.
1da177e4 1152
0610c8a8
DH
1153 When a hung task is detected, the kernel will print the
1154 current stack trace (which you should report), but the
1155 task will stay in uninterruptible state. If lockdep is
1156 enabled then all held locks will also be reported. This
1157 feature has negligible overhead.
871751e2 1158
0610c8a8
DH
1159config DEFAULT_HUNG_TASK_TIMEOUT
1160 int "Default timeout for hung task detection (in seconds)"
1161 depends on DETECT_HUNG_TASK
1162 default 120
f0630fff 1163 help
0610c8a8
DH
1164 This option controls the default timeout (in seconds) used
1165 to determine when a task has become non-responsive and should
1166 be considered hung.
f0630fff 1167
0610c8a8
DH
1168 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1169 sysctl or by writing a value to
1170 /proc/sys/kernel/hung_task_timeout_secs.
8ff12cfc 1171
0610c8a8
DH
1172 A timeout of 0 disables the check. The default is two minutes.
1173 Keeping the default should be fine in most cases.
b69ec42b 1174
0610c8a8
DH
1175config BOOTPARAM_HUNG_TASK_PANIC
1176 bool "Panic (Reboot) On Hung Tasks"
1177 depends on DETECT_HUNG_TASK
3bba00d7 1178 help
0610c8a8
DH
1179 Say Y here to enable the kernel to panic on "hung tasks",
1180 which are bugs that cause the kernel to leave a task stuck
1181 in uninterruptible "D" state.
3bba00d7 1182
0610c8a8
DH
1183 The panic can be used in combination with panic_timeout,
1184 to cause the system to reboot automatically after a
1185 hung task has been detected. This feature is useful for
1186 high-availability systems that have uptime guarantees and
1187 where a hung tasks must be resolved ASAP.
bf96d1e3 1188
0610c8a8 1189 Say N if unsure.
bf96d1e3 1190
82607adc
TH
1191config WQ_WATCHDOG
1192 bool "Detect Workqueue Stalls"
1193 depends on DEBUG_KERNEL
1194 help
1195 Say Y here to enable stall detection on workqueues. If a
1196 worker pool doesn't make forward progress on a pending work
1197 item for over a given amount of time, 30s by default, a
1198 warning message is printed along with dump of workqueue
1199 state. This can be configured through kernel parameter
1200 "workqueue.watchdog_thresh" and its sysfs counterpart.
1201
63638450
TH
1202config WQ_CPU_INTENSIVE_REPORT
1203 bool "Report per-cpu work items which hog CPU for too long"
1204 depends on DEBUG_KERNEL
1205 help
1206 Say Y here to enable reporting of concurrency-managed per-cpu work
1207 items that hog CPUs for longer than
b2ec116a 1208 workqueue.cpu_intensive_thresh_us. Workqueue automatically
63638450
TH
1209 detects and excludes them from concurrency management to prevent
1210 them from stalling other per-cpu work items. Occassional
1211 triggering may not necessarily indicate a problem. Repeated
1212 triggering likely indicates that the work item should be switched
1213 to use an unbound workqueue.
1214
30428ef5
KK
1215config TEST_LOCKUP
1216 tristate "Test module to generate lockups"
63646bc9 1217 depends on m
30428ef5
KK
1218 help
1219 This builds the "test_lockup" module that helps to make sure
1220 that watchdogs and lockup detectors are working properly.
1221
1222 Depending on module parameters it could emulate soft or hard
1223 lockup, "hung task", or locking arbitrary lock for a long time.
1224 Also it could generate series of lockups with cooling-down periods.
1225
1226 If unsure, say N.
1227
92aef8fb
DH
1228endmenu # "Debug lockups and hangs"
1229
ebebdd09 1230menu "Scheduler Debugging"
5800dc3c 1231
0610c8a8
DH
1232config SCHED_DEBUG
1233 bool "Collect scheduler debugging info"
35260cf5 1234 depends on DEBUG_KERNEL && DEBUG_FS
0610c8a8 1235 default y
0822ee4a 1236 help
1e90e35b 1237 If you say Y here, the /sys/kernel/debug/sched file will be provided
0610c8a8
DH
1238 that can help debug the scheduler. The runtime overhead of this
1239 option is minimal.
0822ee4a 1240
f6db8347
NR
1241config SCHED_INFO
1242 bool
1243 default n
1244
0610c8a8
DH
1245config SCHEDSTATS
1246 bool "Collect scheduler statistics"
1247 depends on DEBUG_KERNEL && PROC_FS
f6db8347 1248 select SCHED_INFO
0610c8a8
DH
1249 help
1250 If you say Y here, additional code will be inserted into the
1251 scheduler and related routines to collect statistics about
1252 scheduler behavior and provide them in /proc/schedstat. These
1253 stats may be useful for both tuning and debugging the scheduler
1254 If you aren't debugging the scheduler or trying to tune a specific
1255 application, you can say N to avoid the very slight overhead
1256 this adds.
0822ee4a 1257
ebebdd09 1258endmenu
0d9e2632 1259
3c17ad19
JS
1260config DEBUG_TIMEKEEPING
1261 bool "Enable extra timekeeping sanity checking"
1262 help
1263 This option will enable additional timekeeping sanity checks
1264 which may be helpful when diagnosing issues where timekeeping
1265 problems are suspected.
1266
1267 This may include checks in the timekeeping hotpaths, so this
1268 option may have a (very small) performance impact to some
1269 workloads.
1270
1271 If unsure, say N.
1272
1da177e4
LT
1273config DEBUG_PREEMPT
1274 bool "Debug preemptible kernel"
9f472869 1275 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1da177e4
LT
1276 help
1277 If you say Y here then the kernel will use a debug variant of the
1278 commonly used smp_processor_id() function and will print warnings
1279 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1280 will detect preemption count underflows.
1281
cc600391
HY
1282 This option has potential to introduce high runtime overhead,
1283 depending on workload as it triggers debugging routines for each
1284 this_cpu operation. It should only be used for debugging purposes.
1285
9eade16b
DH
1286menu "Lock Debugging (spinlocks, mutexes, etc...)"
1287
f07cbebb
WL
1288config LOCK_DEBUGGING_SUPPORT
1289 bool
1290 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1291 default y
1292
19193bca
WL
1293config PROVE_LOCKING
1294 bool "Lock debugging: prove locking correctness"
1295 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1296 select LOCKDEP
1297 select DEBUG_SPINLOCK
bb630f9f 1298 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca 1299 select DEBUG_RT_MUTEXES if RT_MUTEXES
c71fd893 1300 select DEBUG_RWSEMS
19193bca
WL
1301 select DEBUG_WW_MUTEX_SLOWPATH
1302 select DEBUG_LOCK_ALLOC
8fd8ad5c 1303 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
19193bca
WL
1304 select TRACE_IRQFLAGS
1305 default n
1306 help
1307 This feature enables the kernel to prove that all locking
1308 that occurs in the kernel runtime is mathematically
1309 correct: that under no circumstance could an arbitrary (and
1310 not yet triggered) combination of observed locking
1311 sequences (on an arbitrary number of CPUs, running an
1312 arbitrary number of tasks and interrupt contexts) cause a
1313 deadlock.
1314
1315 In short, this feature enables the kernel to report locking
1316 related deadlocks before they actually occur.
1317
1318 The proof does not depend on how hard and complex a
1319 deadlock scenario would be to trigger: how many
1320 participant CPUs, tasks and irq-contexts would be needed
1321 for it to trigger. The proof also does not depend on
1322 timing: if a race and a resulting deadlock is possible
1323 theoretically (no matter how unlikely the race scenario
1324 is), it will be proven so and will immediately be
1325 reported by the kernel (once the event is observed that
1326 makes the deadlock theoretically possible).
1327
1328 If a deadlock is impossible (i.e. the locking rules, as
1329 observed by the kernel, are mathematically correct), the
1330 kernel reports nothing.
1331
1332 NOTE: this feature can also be enabled for rwlocks, mutexes
1333 and rwsems - in which case all dependencies between these
1334 different locking variants are observed and mapped too, and
1335 the proof of observed correctness is also maintained for an
1336 arbitrary combination of these separate locking variants.
1337
387b1468 1338 For more details, see Documentation/locking/lockdep-design.rst.
19193bca 1339
de8f5e4f
PZ
1340config PROVE_RAW_LOCK_NESTING
1341 bool "Enable raw_spinlock - spinlock nesting checks"
1342 depends on PROVE_LOCKING
1343 default n
1344 help
1345 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1346 that the lock nesting rules for PREEMPT_RT enabled kernels are
1347 not violated.
1348
1349 NOTE: There are known nesting problems. So if you enable this
1350 option expect lockdep splats until these problems have been fully
1351 addressed which is work in progress. This config switch allows to
1352 identify and analyze these problems. It will be removed and the
9dbbc3b9 1353 check permanently enabled once the main issues have been fixed.
de8f5e4f
PZ
1354
1355 If unsure, select N.
1356
19193bca
WL
1357config LOCK_STAT
1358 bool "Lock usage statistics"
1359 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1360 select LOCKDEP
1361 select DEBUG_SPINLOCK
bb630f9f 1362 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca
WL
1363 select DEBUG_RT_MUTEXES if RT_MUTEXES
1364 select DEBUG_LOCK_ALLOC
1365 default n
1366 help
1367 This feature enables tracking lock contention points
1368
387b1468 1369 For more details, see Documentation/locking/lockstat.rst
19193bca
WL
1370
1371 This also enables lock events required by "perf lock",
1372 subcommand of perf.
1373 If you want to use "perf lock", you also need to turn on
1374 CONFIG_EVENT_TRACING.
1375
1376 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1377 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1378
e7eebaf6
IM
1379config DEBUG_RT_MUTEXES
1380 bool "RT Mutex debugging, deadlock detection"
e7eebaf6
IM
1381 depends on DEBUG_KERNEL && RT_MUTEXES
1382 help
1383 This allows rt mutex semantics violations and rt mutex related
1384 deadlocks (lockups) to be detected and reported automatically.
1385
1da177e4 1386config DEBUG_SPINLOCK
4d9f34ad 1387 bool "Spinlock and rw-lock debugging: basic checks"
1da177e4 1388 depends on DEBUG_KERNEL
e335e3eb 1389 select UNINLINE_SPIN_UNLOCK
1da177e4
LT
1390 help
1391 Say Y here and build SMP to catch missing spinlock initialization
1392 and certain other kinds of spinlock errors commonly made. This is
1393 best used in conjunction with the NMI watchdog so that spinlock
1394 deadlocks are also debuggable.
1395
4d9f34ad
IM
1396config DEBUG_MUTEXES
1397 bool "Mutex debugging: basic checks"
bb630f9f 1398 depends on DEBUG_KERNEL && !PREEMPT_RT
4d9f34ad
IM
1399 help
1400 This feature allows mutex semantics violations to be detected and
1401 reported.
1402
23010027
DV
1403config DEBUG_WW_MUTEX_SLOWPATH
1404 bool "Wait/wound mutex debugging: Slowpath testing"
f07cbebb 1405 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
23010027
DV
1406 select DEBUG_LOCK_ALLOC
1407 select DEBUG_SPINLOCK
bb630f9f
TG
1408 select DEBUG_MUTEXES if !PREEMPT_RT
1409 select DEBUG_RT_MUTEXES if PREEMPT_RT
23010027
DV
1410 help
1411 This feature enables slowpath testing for w/w mutex users by
1412 injecting additional -EDEADLK wound/backoff cases. Together with
1413 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1414 will test all possible w/w mutex interface abuse with the
1415 exception of simply not acquiring all the required locks.
4d692373
RC
1416 Note that this feature can introduce significant overhead, so
1417 it really should not be enabled in a production or distro kernel,
1418 even a debug kernel. If you are a driver writer, enable it. If
1419 you are a distro, do not.
23010027 1420
5149cbac
WL
1421config DEBUG_RWSEMS
1422 bool "RW Semaphore debugging: basic checks"
c71fd893 1423 depends on DEBUG_KERNEL
5149cbac 1424 help
c71fd893
WL
1425 This debugging feature allows mismatched rw semaphore locks
1426 and unlocks to be detected and reported.
5149cbac 1427
4d9f34ad
IM
1428config DEBUG_LOCK_ALLOC
1429 bool "Lock debugging: detect incorrect freeing of live locks"
f07cbebb 1430 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1431 select DEBUG_SPINLOCK
bb630f9f 1432 select DEBUG_MUTEXES if !PREEMPT_RT
f5694788 1433 select DEBUG_RT_MUTEXES if RT_MUTEXES
4d9f34ad
IM
1434 select LOCKDEP
1435 help
1436 This feature will check whether any held lock (spinlock, rwlock,
1437 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1438 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1439 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1440 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1441 held during task exit.
1442
4d9f34ad
IM
1443config LOCKDEP
1444 bool
f07cbebb 1445 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1446 select STACKTRACE
4d9f34ad
IM
1447 select KALLSYMS
1448 select KALLSYMS_ALL
1449
395102db
DJ
1450config LOCKDEP_SMALL
1451 bool
1452
5dc33592
TH
1453config LOCKDEP_BITS
1454 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1455 depends on LOCKDEP && !LOCKDEP_SMALL
1456 range 10 30
1457 default 15
1458 help
1459 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1460
1461config LOCKDEP_CHAINS_BITS
1462 int "Bitsize for MAX_LOCKDEP_CHAINS"
1463 depends on LOCKDEP && !LOCKDEP_SMALL
1464 range 10 30
1465 default 16
1466 help
1467 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1468
1469config LOCKDEP_STACK_TRACE_BITS
1470 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1471 depends on LOCKDEP && !LOCKDEP_SMALL
1472 range 10 30
1473 default 19
1474 help
1475 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1476
1477config LOCKDEP_STACK_TRACE_HASH_BITS
1478 int "Bitsize for STACK_TRACE_HASH_SIZE"
1479 depends on LOCKDEP && !LOCKDEP_SMALL
1480 range 10 30
1481 default 14
1482 help
f478b998 1483 Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
5dc33592
TH
1484
1485config LOCKDEP_CIRCULAR_QUEUE_BITS
1486 int "Bitsize for elements in circular_queue struct"
1487 depends on LOCKDEP
1488 range 10 30
1489 default 12
1490 help
1491 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1492
4d9f34ad
IM
1493config DEBUG_LOCKDEP
1494 bool "Lock dependency engine debugging"
517e7aa5 1495 depends on DEBUG_KERNEL && LOCKDEP
997acaf6 1496 select DEBUG_IRQFLAGS
4d9f34ad
IM
1497 help
1498 If you say Y here, the lock dependency engine will do
1499 additional runtime checks to debug itself, at the price
1500 of more runtime overhead.
1501
d902db1e
FW
1502config DEBUG_ATOMIC_SLEEP
1503 bool "Sleep inside atomic section checking"
e8f7c70f 1504 select PREEMPT_COUNT
1da177e4 1505 depends on DEBUG_KERNEL
87a4c375 1506 depends on !ARCH_NO_PREEMPT
1da177e4
LT
1507 help
1508 If you say Y here, various routines which may sleep will become very
d902db1e
FW
1509 noisy if they are called inside atomic sections: when a spinlock is
1510 held, inside an rcu read side critical section, inside preempt disabled
1511 sections, inside an interrupt, etc...
1da177e4 1512
cae2ed9a
IM
1513config DEBUG_LOCKING_API_SELFTESTS
1514 bool "Locking API boot-time self-tests"
1515 depends on DEBUG_KERNEL
1516 help
1517 Say Y here if you want the kernel to run a short self-test during
1518 bootup. The self-test checks whether common types of locking bugs
1519 are detected by debugging mechanisms or not. (if you disable
9dbbc3b9 1520 lock debugging then those bugs won't be detected of course.)
cae2ed9a
IM
1521 The following locking APIs are covered: spinlocks, rwlocks,
1522 mutexes and rwsems.
1523
0af3fe1e
PM
1524config LOCK_TORTURE_TEST
1525 tristate "torture tests for locking"
1526 depends on DEBUG_KERNEL
1527 select TORTURE_TEST
0af3fe1e
PM
1528 help
1529 This option provides a kernel module that runs torture tests
1530 on kernel locking primitives. The kernel module may be built
1531 after the fact on the running kernel to be tested, if desired.
1532
1533 Say Y here if you want kernel locking-primitive torture tests
1534 to be built into the kernel.
1535 Say M if you want these torture tests to build as a module.
1536 Say N if you are unsure.
1537
f2a5fec1
CW
1538config WW_MUTEX_SELFTEST
1539 tristate "Wait/wound mutex selftests"
1540 help
1541 This option provides a kernel module that runs tests on the
1542 on the struct ww_mutex locking API.
1543
1544 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1545 with this test harness.
1546
1547 Say M if you want these self tests to build as a module.
1548 Say N if you are unsure.
1549
e9d338a0
PM
1550config SCF_TORTURE_TEST
1551 tristate "torture tests for smp_call_function*()"
1552 depends on DEBUG_KERNEL
1553 select TORTURE_TEST
1554 help
1555 This option provides a kernel module that runs torture tests
1556 on the smp_call_function() family of primitives. The kernel
1557 module may be built after the fact on the running kernel to
1558 be tested, if desired.
1559
35feb604
PM
1560config CSD_LOCK_WAIT_DEBUG
1561 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1562 depends on DEBUG_KERNEL
1563 depends on 64BIT
1564 default n
1565 help
1566 This option enables debug prints when CPUs are slow to respond
1567 to the smp_call_function*() IPI wrappers. These debug prints
1568 include the IPI handler function currently executing (if any)
1569 and relevant stack traces.
1570
c5219860
PM
1571config CSD_LOCK_WAIT_DEBUG_DEFAULT
1572 bool "Default csd_lock_wait() debugging on at boot time"
1573 depends on CSD_LOCK_WAIT_DEBUG
1574 depends on 64BIT
1575 default n
1576 help
1577 This option causes the csdlock_debug= kernel boot parameter to
1578 default to 1 (basic debugging) instead of 0 (no debugging).
1579
9eade16b 1580endmenu # lock debugging
8637c099 1581
9eade16b 1582config TRACE_IRQFLAGS
ed004953 1583 depends on TRACE_IRQFLAGS_SUPPORT
9eade16b 1584 bool
5ca43f6c 1585 help
9eade16b
DH
1586 Enables hooks to interrupt enabling and disabling for
1587 either tracing or lock debugging.
5ca43f6c 1588
ed004953 1589config TRACE_IRQFLAGS_NMI
1590 def_bool y
1591 depends on TRACE_IRQFLAGS
1592 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1593
1a3ea611
PM
1594config NMI_CHECK_CPU
1595 bool "Debugging for CPUs failing to respond to backtrace requests"
1596 depends on DEBUG_KERNEL
1597 depends on X86
1598 default n
1599 help
1600 Enables debug prints when a CPU fails to respond to a given
1601 backtrace NMI. These prints provide some reasons why a CPU
1602 might legitimately be failing to respond, for example, if it
1603 is offline of if ignore_nmis is set.
1604
997acaf6
MR
1605config DEBUG_IRQFLAGS
1606 bool "Debug IRQ flag manipulation"
1607 help
1608 Enables checks for potentially unsafe enabling or disabling of
1609 interrupts, such as calling raw_local_irq_restore() when interrupts
1610 are enabled.
1611
8637c099 1612config STACKTRACE
0c38e1fe 1613 bool "Stack backtrace support"
8637c099 1614 depends on STACKTRACE_SUPPORT
0c38e1fe
DJ
1615 help
1616 This option causes the kernel to create a /proc/pid/stack for
1617 every process, showing its current stack trace.
1618 It is also used by various kernel debugging features that require
1619 stack trace generation.
5ca43f6c 1620
eecabf56
TT
1621config WARN_ALL_UNSEEDED_RANDOM
1622 bool "Warn for all uses of unseeded randomness"
1623 default n
d06bfd19
JD
1624 help
1625 Some parts of the kernel contain bugs relating to their use of
1626 cryptographically secure random numbers before it's actually possible
1627 to generate those numbers securely. This setting ensures that these
1628 flaws don't go unnoticed, by enabling a message, should this ever
1629 occur. This will allow people with obscure setups to know when things
1630 are going wrong, so that they might contact developers about fixing
1631 it.
1632
eecabf56
TT
1633 Unfortunately, on some models of some architectures getting
1634 a fully seeded CRNG is extremely difficult, and so this can
1635 result in dmesg getting spammed for a surprisingly long
1636 time. This is really bad from a security perspective, and
1637 so architecture maintainers really need to do what they can
1638 to get the CRNG seeded sooner after the system is booted.
4c5d114e 1639 However, since users cannot do anything actionable to
cc1e127b 1640 address this, by default this option is disabled.
eecabf56
TT
1641
1642 Say Y here if you want to receive warnings for all uses of
1643 unseeded randomness. This will be of use primarily for
4c5d114e 1644 those developers interested in improving the security of
eecabf56
TT
1645 Linux kernels running on their architecture (or
1646 subarchitecture).
d06bfd19 1647
1da177e4
LT
1648config DEBUG_KOBJECT
1649 bool "kobject debugging"
1650 depends on DEBUG_KERNEL
1651 help
1652 If you say Y here, some extra kobject debugging messages will be sent
aca52c39 1653 to the syslog.
1da177e4 1654
c817a67e
RK
1655config DEBUG_KOBJECT_RELEASE
1656 bool "kobject release debugging"
2a999aa0 1657 depends on DEBUG_OBJECTS_TIMERS
c817a67e
RK
1658 help
1659 kobjects are reference counted objects. This means that their
1660 last reference count put is not predictable, and the kobject can
b6c69474 1661 live on past the point at which a driver decides to drop its
c817a67e
RK
1662 initial reference to the kobject gained on allocation. An
1663 example of this would be a struct device which has just been
1664 unregistered.
1665
1666 However, some buggy drivers assume that after such an operation,
1667 the memory backing the kobject can be immediately freed. This
1668 goes completely against the principles of a refcounted object.
1669
1670 If you say Y here, the kernel will delay the release of kobjects
1671 on the last reference count to improve the visibility of this
1672 kind of kobject release bug.
1673
9b2a60c4
CM
1674config HAVE_DEBUG_BUGVERBOSE
1675 bool
1676
3be5cbcd 1677menu "Debug kernel data structures"
1da177e4 1678
199a9afc
DJ
1679config DEBUG_LIST
1680 bool "Debug linked list manipulation"
aa9f10d5 1681 depends on DEBUG_KERNEL
aebc7b0d 1682 select LIST_HARDENED
199a9afc 1683 help
aebc7b0d
ME
1684 Enable this to turn on extended checks in the linked-list walking
1685 routines.
1686
1687 This option trades better quality error reports for performance, and
1688 is more suitable for kernel debugging. If you care about performance,
1689 you should only enable CONFIG_LIST_HARDENED instead.
199a9afc
DJ
1690
1691 If unsure, say N.
1692
8e18faea 1693config DEBUG_PLIST
b8cfff68
DS
1694 bool "Debug priority linked list manipulation"
1695 depends on DEBUG_KERNEL
1696 help
1697 Enable this to turn on extended checks in the priority-ordered
1698 linked-list (plist) walking routines. This checks the entire
1699 list multiple times during each manipulation.
1700
1701 If unsure, say N.
1702
d6ec0842
JA
1703config DEBUG_SG
1704 bool "Debug SG table operations"
1705 depends on DEBUG_KERNEL
1706 help
1707 Enable this to turn on checks on scatter-gather tables. This can
1708 help find problems with drivers that do not properly initialize
1709 their sg tables.
1710
1711 If unsure, say N.
1712
1b2439db
AV
1713config DEBUG_NOTIFIERS
1714 bool "Debug notifier call chains"
1715 depends on DEBUG_KERNEL
1716 help
1717 Enable this to turn on sanity checking for notifier call chains.
1718 This is most useful for kernel developers to make sure that
1719 modules properly unregister themselves from notifier chains.
1720 This is a relatively cheap check but if you care about maximum
1721 performance, say N.
1722
8c8d2d96
KO
1723config DEBUG_CLOSURES
1724 bool "Debug closures (bcache async widgits)"
1725 depends on CLOSURES
1726 select DEBUG_FS
1727 help
1728 Keeps all active closures in a linked list and provides a debugfs
1729 interface to list them, which makes it possible to see asynchronous
1730 operations that get stuck.
1731
54a611b6
LH
1732config DEBUG_MAPLE_TREE
1733 bool "Debug maple trees"
1734 depends on DEBUG_KERNEL
1735 help
1736 Enable maple tree debugging information and extra validations.
1737
1738 If unsure, say N.
1739
3be5cbcd
CD
1740endmenu
1741
e0e81739
DH
1742config DEBUG_CREDENTIALS
1743 bool "Debug credential management"
1744 depends on DEBUG_KERNEL
1745 help
1746 Enable this to turn on some debug checking for credential
1747 management. The additional code keeps track of the number of
1748 pointers from task_structs to any given cred struct, and checks to
1749 see that this number never exceeds the usage count of the cred
1750 struct.
1751
1752 Furthermore, if SELinux is enabled, this also checks that the
1753 security pointer in the cred struct is never seen to be invalid.
1754
1755 If unsure, say N.
1756
43a0a2a7 1757source "kernel/rcu/Kconfig.debug"
2f03e3ca 1758
f303fccb
TH
1759config DEBUG_WQ_FORCE_RR_CPU
1760 bool "Force round-robin CPU selection for unbound work items"
1761 depends on DEBUG_KERNEL
1762 default n
1763 help
1764 Workqueue used to implicitly guarantee that work items queued
1765 without explicit CPU specified are put on the local CPU. This
1766 guarantee is no longer true and while local CPU is still
1767 preferred work items may be put on foreign CPUs. Kernel
1768 parameter "workqueue.debug_force_rr_cpu" is added to force
1769 round-robin CPU selection to flush out usages which depend on the
1770 now broken guarantee. This config option enables the debug
1771 feature by default. When enabled, memory and cache locality will
1772 be impacted.
1773
757c989b
TG
1774config CPU_HOTPLUG_STATE_CONTROL
1775 bool "Enable CPU hotplug state control"
1776 depends on DEBUG_KERNEL
1777 depends on HOTPLUG_CPU
1778 default n
1779 help
1780 Allows to write steps between "offline" and "online" to the CPUs
1781 sysfs target file so states can be stepped granular. This is a debug
1782 option for now as the hotplug machinery cannot be stopped and
1783 restarted at arbitrary points yet.
1784
1785 Say N if your are unsure.
1786
09a74952
CD
1787config LATENCYTOP
1788 bool "Latency measuring infrastructure"
1789 depends on DEBUG_KERNEL
1790 depends on STACKTRACE_SUPPORT
1791 depends on PROC_FS
7d37cb2c 1792 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
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1793 select KALLSYMS
1794 select KALLSYMS_ALL
1795 select STACKTRACE
1796 select SCHEDSTATS
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1797 help
1798 Enable this option if you want to use the LatencyTOP tool
1799 to find out which userspace is blocking on what kernel operations.
1800
6ab42860
TH
1801config DEBUG_CGROUP_REF
1802 bool "Disable inlining of cgroup css reference count functions"
1803 depends on DEBUG_KERNEL
1804 depends on CGROUPS
1805 depends on KPROBES
1806 default n
1807 help
1808 Force cgroup css reference count functions to not be inlined so
1809 that they can be kprobed for debugging.
1810
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1811source "kernel/trace/Kconfig"
1812
1813config PROVIDE_OHCI1394_DMA_INIT
1814 bool "Remote debugging over FireWire early on boot"
1815 depends on PCI && X86
1816 help
1817 If you want to debug problems which hang or crash the kernel early
1818 on boot and the crashing machine has a FireWire port, you can use
1819 this feature to remotely access the memory of the crashed machine
1820 over FireWire. This employs remote DMA as part of the OHCI1394
1821 specification which is now the standard for FireWire controllers.
1822
1823 With remote DMA, you can monitor the printk buffer remotely using
1824 firescope and access all memory below 4GB using fireproxy from gdb.
1825 Even controlling a kernel debugger is possible using remote DMA.
1826
1827 Usage:
1828
1829 If ohci1394_dma=early is used as boot parameter, it will initialize
1830 all OHCI1394 controllers which are found in the PCI config space.
1831
1832 As all changes to the FireWire bus such as enabling and disabling
1833 devices cause a bus reset and thereby disable remote DMA for all
1834 devices, be sure to have the cable plugged and FireWire enabled on
1835 the debugging host before booting the debug target for debugging.
1836
1837 This code (~1k) is freed after boot. By then, the firewire stack
1838 in charge of the OHCI-1394 controllers should be used instead.
1839
a74e2a22 1840 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
09a74952 1841
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CD
1842source "samples/Kconfig"
1843
1844config ARCH_HAS_DEVMEM_IS_ALLOWED
1845 bool
1846
1847config STRICT_DEVMEM
1848 bool "Filter access to /dev/mem"
1849 depends on MMU && DEVMEM
527701ed 1850 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
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CD
1851 default y if PPC || X86 || ARM64
1852 help
1853 If this option is disabled, you allow userspace (root) access to all
1854 of memory, including kernel and userspace memory. Accidental
1855 access to this is obviously disastrous, but specific access can
1856 be used by people debugging the kernel. Note that with PAT support
1857 enabled, even in this case there are restrictions on /dev/mem
1858 use due to the cache aliasing requirements.
1859
1860 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1861 file only allows userspace access to PCI space and the BIOS code and
1862 data regions. This is sufficient for dosemu and X and all common
1863 users of /dev/mem.
1864
1865 If in doubt, say Y.
1866
1867config IO_STRICT_DEVMEM
1868 bool "Filter I/O access to /dev/mem"
1869 depends on STRICT_DEVMEM
1870 help
1871 If this option is disabled, you allow userspace (root) access to all
1872 io-memory regardless of whether a driver is actively using that
1873 range. Accidental access to this is obviously disastrous, but
1874 specific access can be used by people debugging kernel drivers.
1875
1876 If this option is switched on, the /dev/mem file only allows
1877 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1878 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1879 if the driver using a given range cannot be disabled.
1880
1881 If in doubt, say Y.
1882
1883menu "$(SRCARCH) Debugging"
1884
1885source "arch/$(SRCARCH)/Kconfig.debug"
1886
1887endmenu
1888
1889menu "Kernel Testing and Coverage"
1890
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1891source "lib/kunit/Kconfig"
1892
8d438288
AM
1893config NOTIFIER_ERROR_INJECTION
1894 tristate "Notifier error injection"
1895 depends on DEBUG_KERNEL
1896 select DEBUG_FS
1897 help
e41e85cc 1898 This option provides the ability to inject artificial errors to
8d438288
AM
1899 specified notifier chain callbacks. It is useful to test the error
1900 handling of notifier call chain failures.
1901
1902 Say N if unsure.
1903
048b9c35
AM
1904config PM_NOTIFIER_ERROR_INJECT
1905 tristate "PM notifier error injection module"
1906 depends on PM && NOTIFIER_ERROR_INJECTION
1907 default m if PM_DEBUG
1908 help
e41e85cc 1909 This option provides the ability to inject artificial errors to
048b9c35
AM
1910 PM notifier chain callbacks. It is controlled through debugfs
1911 interface /sys/kernel/debug/notifier-error-inject/pm
1912
1913 If the notifier call chain should be failed with some events
1914 notified, write the error code to "actions/<notifier event>/error".
1915
1916 Example: Inject PM suspend error (-12 = -ENOMEM)
1917
1918 # cd /sys/kernel/debug/notifier-error-inject/pm/
1919 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1920 # echo mem > /sys/power/state
1921 bash: echo: write error: Cannot allocate memory
1922
1923 To compile this code as a module, choose M here: the module will
1924 be called pm-notifier-error-inject.
1925
1926 If unsure, say N.
1927
d526e85f
BH
1928config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1929 tristate "OF reconfig notifier error injection module"
1930 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dd 1931 help
e41e85cc 1932 This option provides the ability to inject artificial errors to
d526e85f 1933 OF reconfig notifier chain callbacks. It is controlled
08dfb4dd 1934 through debugfs interface under
d526e85f 1935 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
08dfb4dd
AM
1936
1937 If the notifier call chain should be failed with some events
1938 notified, write the error code to "actions/<notifier event>/error".
1939
1940 To compile this code as a module, choose M here: the module will
e12a95f4 1941 be called of-reconfig-notifier-error-inject.
08dfb4dd
AM
1942
1943 If unsure, say N.
1944
02fff96a
NA
1945config NETDEV_NOTIFIER_ERROR_INJECT
1946 tristate "Netdev notifier error injection module"
1947 depends on NET && NOTIFIER_ERROR_INJECTION
1948 help
1949 This option provides the ability to inject artificial errors to
1950 netdevice notifier chain callbacks. It is controlled through debugfs
1951 interface /sys/kernel/debug/notifier-error-inject/netdev
1952
1953 If the notifier call chain should be failed with some events
1954 notified, write the error code to "actions/<notifier event>/error".
1955
1956 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1957
1958 # cd /sys/kernel/debug/notifier-error-inject/netdev
1959 # echo -22 > actions/NETDEV_CHANGEMTU/error
1960 # ip link set eth0 mtu 1024
1961 RTNETLINK answers: Invalid argument
1962
1963 To compile this code as a module, choose M here: the module will
1964 be called netdev-notifier-error-inject.
1965
1966 If unsure, say N.
1967
f1b4bd06 1968config FUNCTION_ERROR_INJECTION
a4412fdd 1969 bool "Fault-injections of functions"
f1b4bd06 1970 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
a4412fdd
SRG
1971 help
1972 Add fault injections into various functions that are annotated with
1973 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
ca0f2cfc 1974 value of these functions. This is useful to test error paths of code.
a4412fdd
SRG
1975
1976 If unsure, say N
f1b4bd06 1977
6ff1cb35 1978config FAULT_INJECTION
1ab8509a
AM
1979 bool "Fault-injection framework"
1980 depends on DEBUG_KERNEL
329409ae
AM
1981 help
1982 Provide fault-injection framework.
1983 For more details, see Documentation/fault-injection/.
6ff1cb35 1984
8a8b6502 1985config FAILSLAB
1ab8509a
AM
1986 bool "Fault-injection capability for kmalloc"
1987 depends on FAULT_INJECTION
773ff60e 1988 depends on SLAB || SLUB
8a8b6502 1989 help
1ab8509a 1990 Provide fault-injection capability for kmalloc.
8a8b6502 1991
933e312e 1992config FAIL_PAGE_ALLOC
29b46fa3 1993 bool "Fault-injection capability for alloc_pages()"
1ab8509a 1994 depends on FAULT_INJECTION
933e312e 1995 help
1ab8509a 1996 Provide fault-injection capability for alloc_pages().
933e312e 1997
2c739ced
AL
1998config FAULT_INJECTION_USERCOPY
1999 bool "Fault injection capability for usercopy functions"
2000 depends on FAULT_INJECTION
2001 help
2002 Provides fault-injection capability to inject failures
2003 in usercopy functions (copy_from_user(), get_user(), ...).
2004
c17bb495 2005config FAIL_MAKE_REQUEST
86327d19 2006 bool "Fault-injection capability for disk IO"
581d4e28 2007 depends on FAULT_INJECTION && BLOCK
c17bb495 2008 help
1ab8509a 2009 Provide fault-injection capability for disk IO.
c17bb495 2010
581d4e28 2011config FAIL_IO_TIMEOUT
f4d01439 2012 bool "Fault-injection capability for faking disk interrupts"
581d4e28
JA
2013 depends on FAULT_INJECTION && BLOCK
2014 help
2015 Provide fault-injection capability on end IO handling. This
2016 will make the block layer "forget" an interrupt as configured,
2017 thus exercising the error handling.
2018
2019 Only works with drivers that use the generic timeout handling,
9dbbc3b9 2020 for others it won't do anything.
581d4e28 2021
ab51fbab
DB
2022config FAIL_FUTEX
2023 bool "Fault-injection capability for futexes"
2024 select DEBUG_FS
2025 depends on FAULT_INJECTION && FUTEX
2026 help
2027 Provide fault-injection capability for futexes.
2028
f1b4bd06
MP
2029config FAULT_INJECTION_DEBUG_FS
2030 bool "Debugfs entries for fault-injection capabilities"
2031 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2032 help
2033 Enable configuration of fault-injection capabilities via debugfs.
2034
4b1a29a7
MH
2035config FAIL_FUNCTION
2036 bool "Fault-injection capability for functions"
2037 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2038 help
2039 Provide function-based fault-injection capability.
2040 This will allow you to override a specific function with a return
2041 with given return value. As a result, function caller will see
2042 an error value and have to handle it. This is useful to test the
2043 error handling in various subsystems.
2044
f1b4bd06
MP
2045config FAIL_MMC_REQUEST
2046 bool "Fault-injection capability for MMC IO"
2047 depends on FAULT_INJECTION_DEBUG_FS && MMC
6ff1cb35 2048 help
f1b4bd06
MP
2049 Provide fault-injection capability for MMC IO.
2050 This will make the mmc core return data errors. This is
2051 useful to test the error handling in the mmc block device
2052 and to test how the mmc host driver handles retries from
2053 the block device.
1df49008 2054
c782af25
CL
2055config FAIL_SUNRPC
2056 bool "Fault-injection capability for SunRPC"
2057 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2058 help
2059 Provide fault-injection capability for SunRPC and
2060 its consumers.
2061
4668c7a2
AM
2062config FAULT_INJECTION_CONFIGFS
2063 bool "Configfs interface for fault-injection capabilities"
d325c162
AM
2064 depends on FAULT_INJECTION
2065 select CONFIGFS_FS
4668c7a2
AM
2066 help
2067 This option allows configfs-based drivers to dynamically configure
2068 fault-injection via configfs. Each parameter for driver-specific
2069 fault-injection can be made visible as a configfs attribute in a
2070 configfs group.
2071
2072
1df49008
AM
2073config FAULT_INJECTION_STACKTRACE_FILTER
2074 bool "stacktrace filter for fault-injection capabilities"
4668c7a2
AM
2075 depends on FAULT_INJECTION
2076 depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
1df49008 2077 select STACKTRACE
7d37cb2c 2078 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1df49008
AM
2079 help
2080 Provide stacktrace filter for fault-injection capabilities
267c4025 2081
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2082config ARCH_HAS_KCOV
2083 bool
cc3fa840 2084 help
09a74952
CD
2085 An architecture should select this when it can successfully
2086 build and run with CONFIG_KCOV. This typically requires
2087 disabling instrumentation for some early boot code.
cc3fa840 2088
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2089config CC_HAS_SANCOV_TRACE_PC
2090 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
cc3fa840 2091
cc3fa840 2092
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2093config KCOV
2094 bool "Code coverage for fuzzing"
2095 depends on ARCH_HAS_KCOV
2096 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
22102f45 2097 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
bece04b5 2098 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
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2099 select DEBUG_FS
2100 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
22102f45 2101 select OBJTOOL if HAVE_NOINSTR_HACK
09a74952
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2102 help
2103 KCOV exposes kernel code coverage information in a form suitable
2104 for coverage-guided fuzzing (randomized testing).
cc3fa840 2105
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2106 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2107 different machines and across reboots. If you need stable PC values,
2108 disable RANDOMIZE_BASE.
cc3fa840 2109
09a74952 2110 For more details, see Documentation/dev-tools/kcov.rst.
cc3fa840 2111
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2112config KCOV_ENABLE_COMPARISONS
2113 bool "Enable comparison operands collection by KCOV"
2114 depends on KCOV
2115 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2116 help
2117 KCOV also exposes operands of every comparison in the instrumented
2118 code along with operand sizes and PCs of the comparison instructions.
2119 These operands can be used by fuzzing engines to improve the quality
2120 of fuzzing coverage.
cc3fa840 2121
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2122config KCOV_INSTRUMENT_ALL
2123 bool "Instrument all code by default"
2124 depends on KCOV
2125 default y
2126 help
2127 If you are doing generic system call fuzzing (like e.g. syzkaller),
2128 then you will want to instrument the whole kernel and you should
2129 say y here. If you are doing more targeted fuzzing (like e.g.
2130 filesystem fuzzing with AFL) then you will want to enable coverage
2131 for more specific subsets of files, and should say n here.
84bc809e 2132
5ff3b30a
AK
2133config KCOV_IRQ_AREA_SIZE
2134 hex "Size of interrupt coverage collection area in words"
2135 depends on KCOV
2136 default 0x40000
2137 help
2138 KCOV uses preallocated per-cpu areas to collect coverage from
2139 soft interrupts. This specifies the size of those areas in the
2140 number of unsigned long words.
2141
d3deafaa
VL
2142menuconfig RUNTIME_TESTING_MENU
2143 bool "Runtime Testing"
908009e8 2144 def_bool y
d3deafaa
VL
2145
2146if RUNTIME_TESTING_MENU
881c5149 2147
d5528cc1
GU
2148config TEST_DHRY
2149 tristate "Dhrystone benchmark test"
2150 help
2151 Enable this to include the Dhrystone 2.1 benchmark. This test
2152 calculates the number of Dhrystones per second, and the number of
2153 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2154 by 1757 (the number of Dhrystones per second obtained on the VAX
2155 11/780, nominally a 1 MIPS machine).
2156
2157 To run the benchmark, it needs to be enabled explicitly, either from
2158 the kernel command line (when built-in), or from userspace (when
2159 built-in or modular.
2160
2161 Run once during kernel boot:
2162
2163 test_dhry.run
2164
2165 Set number of iterations from kernel command line:
2166
2167 test_dhry.iterations=<n>
2168
2169 Set number of iterations from userspace:
2170
2171 echo <n> > /sys/module/test_dhry/parameters/iterations
2172
2173 Trigger manual run from userspace:
2174
2175 echo y > /sys/module/test_dhry/parameters/run
2176
2177 If the number of iterations is <= 0, the test will devise a suitable
2178 number of iterations (test runs for at least 2s) automatically.
2179 This process takes ca. 4s.
2180
2181 If unsure, say N.
2182
881c5149
DH
2183config LKDTM
2184 tristate "Linux Kernel Dump Test Tool Module"
2185 depends on DEBUG_FS
881c5149
DH
2186 help
2187 This module enables testing of the different dumping mechanisms by
2188 inducing system failures at predefined crash points.
2189 If you don't need it: say N
2190 Choose M here to compile this code as a module. The module will be
2191 called lkdtm.
2192
2193 Documentation on how to use the module can be found in
10ffebbe 2194 Documentation/fault-injection/provoke-crashes.rst
881c5149 2195
d3c0ca49
SV
2196config CPUMASK_KUNIT_TEST
2197 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
c41e8866
SV
2198 depends on KUNIT
2199 default KUNIT_ALL_TESTS
2200 help
2201 Enable to turn on cpumask tests, running at boot or module load time.
2202
d3c0ca49
SV
2203 For more information on KUnit and unit tests in general, please refer
2204 to the KUnit documentation in Documentation/dev-tools/kunit/.
2205
c41e8866
SV
2206 If unsure, say N.
2207
881c5149 2208config TEST_LIST_SORT
ebd09577
DL
2209 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2210 depends on KUNIT
2211 default KUNIT_ALL_TESTS
881c5149
DH
2212 help
2213 Enable this to turn on 'list_sort()' function test. This test is
e327fd7c
GU
2214 executed only once during system boot (so affects only boot time),
2215 or at module load time.
881c5149
DH
2216
2217 If unsure, say N.
2218
6e24628d
IR
2219config TEST_MIN_HEAP
2220 tristate "Min heap test"
2221 depends on DEBUG_KERNEL || m
2222 help
2223 Enable this to turn on min heap function tests. This test is
2224 executed only once during system boot (so affects only boot time),
2225 or at module load time.
2226
2227 If unsure, say N.
2228
c5adae95 2229config TEST_SORT
36f33b56
DL
2230 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2231 depends on KUNIT
2232 default KUNIT_ALL_TESTS
c5adae95 2233 help
5c4e6798
GU
2234 This option enables the self-test function of 'sort()' at boot,
2235 or at module load time.
c5adae95
KF
2236
2237 If unsure, say N.
2238
5086ea4b
MR
2239config TEST_DIV64
2240 tristate "64bit/32bit division and modulo test"
2241 depends on DEBUG_KERNEL || m
2242 help
2243 Enable this to turn on 'do_div()' function test. This test is
2244 executed only once during system boot (so affects only boot time),
2245 or at module load time.
2246
2247 If unsure, say N.
2248
2d71340f
DH
2249config TEST_IOV_ITER
2250 tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS
2251 depends on KUNIT
2252 default KUNIT_ALL_TESTS
2253 help
2254 Enable this to turn on testing of the operation of the I/O iterator
2255 (iov_iter). This test is executed only once during system boot (so
2256 affects only boot time), or at module load time.
2257
2258 If unsure, say N.
2259
881c5149 2260config KPROBES_SANITY_TEST
dcbb2ee2 2261 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
881c5149
DH
2262 depends on DEBUG_KERNEL
2263 depends on KPROBES
e44e81c5 2264 depends on KUNIT
de3db3f8 2265 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
dcbb2ee2 2266 default KUNIT_ALL_TESTS
881c5149
DH
2267 help
2268 This option provides for testing basic kprobes functionality on
5a6cf77f 2269 boot. Samples of kprobe and kretprobe are inserted and
881c5149
DH
2270 verified for functionality.
2271
2272 Say N if you are unsure.
2273
f4616fab
MH
2274config FPROBE_SANITY_TEST
2275 bool "Self test for fprobe"
2276 depends on DEBUG_KERNEL
2277 depends on FPROBE
2278 depends on KUNIT=y
2279 help
2280 This option will enable testing the fprobe when the system boot.
2281 A series of tests are made to verify that the fprobe is functioning
2282 properly.
2283
2284 Say N if you are unsure.
2285
881c5149
DH
2286config BACKTRACE_SELF_TEST
2287 tristate "Self test for the backtrace code"
2288 depends on DEBUG_KERNEL
881c5149
DH
2289 help
2290 This option provides a kernel module that can be used to test
2291 the kernel stack backtrace code. This option is not useful
2292 for distributions or general kernels, but only for kernel
2293 developers working on architecture code.
2294
2295 Note that if you want to also test saved backtraces, you will
2296 have to enable STACKTRACE as well.
2297
2298 Say N if you are unsure.
2299
914a7b50
ED
2300config TEST_REF_TRACKER
2301 tristate "Self test for reference tracker"
2302 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2303 select REF_TRACKER
2304 help
2305 This option provides a kernel module performing tests
2306 using reference tracker infrastructure.
2307
2308 Say N if you are unsure.
2309
910a742d
ML
2310config RBTREE_TEST
2311 tristate "Red-Black tree test"
7c993e11 2312 depends on DEBUG_KERNEL
910a742d
ML
2313 help
2314 A benchmark measuring the performance of the rbtree library.
2315 Also includes rbtree invariant checks.
2316
4b4f3acc
FB
2317config REED_SOLOMON_TEST
2318 tristate "Reed-Solomon library test"
2319 depends on DEBUG_KERNEL || m
2320 select REED_SOLOMON
2321 select REED_SOLOMON_ENC16
2322 select REED_SOLOMON_DEC16
2323 help
2324 This option enables the self-test function of rslib at boot,
2325 or at module load time.
2326
2327 If unsure, say N.
2328
fff3fd8a
ML
2329config INTERVAL_TREE_TEST
2330 tristate "Interval tree test"
0f789b67 2331 depends on DEBUG_KERNEL
a88cc108 2332 select INTERVAL_TREE
fff3fd8a
ML
2333 help
2334 A benchmark measuring the performance of the interval tree library
2335
623fd807
GT
2336config PERCPU_TEST
2337 tristate "Per cpu operations test"
2338 depends on m && DEBUG_KERNEL
2339 help
2340 Enable this option to build test module which validates per-cpu
2341 operations.
2342
2343 If unsure, say N.
2344
881c5149 2345config ATOMIC64_SELFTEST
55ded955 2346 tristate "Perform an atomic64_t self-test"
881c5149 2347 help
55ded955
GU
2348 Enable this option to test the atomic64_t functions at boot or
2349 at module load time.
881c5149
DH
2350
2351 If unsure, say N.
2352
2353config ASYNC_RAID6_TEST
2354 tristate "Self test for hardware accelerated raid6 recovery"
2355 depends on ASYNC_RAID6_RECOV
2356 select ASYNC_MEMCPY
a7f7f624 2357 help
881c5149
DH
2358 This is a one-shot self test that permutes through the
2359 recovery of all the possible two disk failure scenarios for a
2360 N-disk array. Recovery is performed with the asynchronous
2361 raid6 recovery routines, and will optionally use an offload
2362 engine if one is available.
2363
2364 If unsure, say N.
2365
64d1d77a
AS
2366config TEST_HEXDUMP
2367 tristate "Test functions located in the hexdump module at runtime"
2368
b2ff70a0
MC
2369config STRING_SELFTEST
2370 tristate "Test string functions at runtime"
2371
881c5149
DH
2372config TEST_STRING_HELPERS
2373 tristate "Test functions located in the string_helpers module at runtime"
2374
2375config TEST_KSTRTOX
2376 tristate "Test kstrto*() family of functions at runtime"
2377
707cc728
RV
2378config TEST_PRINTF
2379 tristate "Test printf() family of functions at runtime"
2380
50f530e1
RF
2381config TEST_SCANF
2382 tristate "Test scanf() family of functions at runtime"
2383
5fd003f5
DD
2384config TEST_BITMAP
2385 tristate "Test bitmap_*() family of functions at runtime"
5fd003f5
DD
2386 help
2387 Enable this option to test the bitmap functions at boot.
2388
2389 If unsure, say N.
2390
cfaff0e5
AS
2391config TEST_UUID
2392 tristate "Test functions located in the uuid module at runtime"
2393
ad3d6c72
MW
2394config TEST_XARRAY
2395 tristate "Test the XArray code at runtime"
2396
120b1162 2397config TEST_MAPLE_TREE
a5199577
LH
2398 tristate "Test the Maple Tree code at runtime or module load"
2399 help
2400 Enable this option to test the maple tree code functions at boot, or
2401 when the module is loaded. Enable "Debug Maple Trees" will enable
2402 more verbose output on failures.
2403
2404 If unsure, say N.
120b1162 2405
7e1e7763 2406config TEST_RHASHTABLE
9d6dbe1b 2407 tristate "Perform selftest on resizable hash table"
7e1e7763
TG
2408 help
2409 Enable this option to test the rhashtable functions at boot.
2410
2411 If unsure, say N.
2412
8ab8ba38
MW
2413config TEST_IDA
2414 tristate "Perform selftest on IDA functions"
2415
44091d29
JP
2416config TEST_PARMAN
2417 tristate "Perform selftest on priority array manager"
44091d29
JP
2418 depends on PARMAN
2419 help
2420 Enable this option to test priority array manager on boot
2421 (or module load).
2422
2423 If unsure, say N.
2424
6aed82de
DL
2425config TEST_IRQ_TIMINGS
2426 bool "IRQ timings selftest"
2427 depends on IRQ_TIMINGS
2428 help
2429 Enable this option to test the irq timings code on boot.
2430
2431 If unsure, say N.
2432
8a6f0b47 2433config TEST_LKM
93e9ef83 2434 tristate "Test module loading with 'hello world' module"
93e9ef83
KC
2435 depends on m
2436 help
2437 This builds the "test_module" module that emits "Hello, world"
2438 on printk when loaded. It is designed to be used for basic
2439 evaluation of the module loading subsystem (for example when
2440 validating module verification). It lacks any extra dependencies,
2441 and will not normally be loaded by the system unless explicitly
2442 requested by name.
2443
2444 If unsure, say N.
2445
c348c163 2446config TEST_BITOPS
6af132f3 2447 tristate "Test module for compilation of bitops operations"
c348c163
JB
2448 depends on m
2449 help
2450 This builds the "test_bitops" module that is much like the
2451 TEST_LKM module except that it does a basic exercise of the
6af132f3
WY
2452 set/clear_bit macros and get_count_order/long to make sure there are
2453 no compiler warnings from C=1 sparse checker or -Wextra
2454 compilations. It has no dependencies and doesn't run or load unless
2455 explicitly requested by name. for example: modprobe test_bitops.
c348c163
JB
2456
2457 If unsure, say N.
2458
3f21a6b7
URS
2459config TEST_VMALLOC
2460 tristate "Test module for stress/performance analysis of vmalloc allocator"
2461 default n
2462 depends on MMU
2463 depends on m
2464 help
2465 This builds the "test_vmalloc" module that should be used for
2466 stress and performance analysis. So, any new change for vmalloc
2467 subsystem can be evaluated from performance and stability point
2468 of view.
2469
2470 If unsure, say N.
2471
3e2a4c18
KC
2472config TEST_USER_COPY
2473 tristate "Test user/kernel boundary protections"
3e2a4c18
KC
2474 depends on m
2475 help
2476 This builds the "test_user_copy" module that runs sanity checks
2477 on the copy_to/from_user infrastructure, making sure basic
2478 user/kernel boundary testing is working. If it fails to load,
2479 a regression has been detected in the user/kernel memory boundary
2480 protections.
2481
2482 If unsure, say N.
2483
64a8946b
AS
2484config TEST_BPF
2485 tristate "Test BPF filter functionality"
98920ba6 2486 depends on m && NET
64a8946b
AS
2487 help
2488 This builds the "test_bpf" module that runs various test vectors
2489 against the BPF interpreter or BPF JIT compiler depending on the
2490 current setting. This is in particular useful for BPF JIT compiler
2491 development, but also to run regression tests against changes in
3c731eba
AS
2492 the interpreter code. It also enables test stubs for eBPF maps and
2493 verifier used by user space verifier testsuite.
64a8946b
AS
2494
2495 If unsure, say N.
2496
509e56b3
MB
2497config TEST_BLACKHOLE_DEV
2498 tristate "Test blackhole netdev functionality"
2499 depends on m && NET
2500 help
2501 This builds the "test_blackhole_dev" module that validates the
2502 data path through this blackhole netdev.
2503
2504 If unsure, say N.
2505
dceeb3e7 2506config FIND_BIT_BENCHMARK
4441fca0 2507 tristate "Test find_bit functions"
4441fca0
YN
2508 help
2509 This builds the "test_find_bit" module that measure find_*_bit()
2510 functions performance.
2511
2512 If unsure, say N.
2513
0a8adf58
KC
2514config TEST_FIRMWARE
2515 tristate "Test firmware loading via userspace interface"
0a8adf58
KC
2516 depends on FW_LOADER
2517 help
2518 This builds the "test_firmware" module that creates a userspace
2519 interface for testing firmware loading. This can be used to
2520 control the triggering of firmware loading without needing an
2521 actual firmware-using device. The contents can be rechecked by
2522 userspace.
2523
2524 If unsure, say N.
2525
9308f2f9
LR
2526config TEST_SYSCTL
2527 tristate "sysctl test driver"
9308f2f9
LR
2528 depends on PROC_SYSCTL
2529 help
2530 This builds the "test_sysctl" module. This driver enables to test the
2531 proc sysctl interfaces available to drivers safely without affecting
2532 production knobs which might alter system functionality.
2533
2534 If unsure, say N.
2535
d2585f51 2536config BITFIELD_KUNIT
dcbb2ee2 2537 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
d2585f51 2538 depends on KUNIT
dcbb2ee2 2539 default KUNIT_ALL_TESTS
d2585f51
VMI
2540 help
2541 Enable this option to test the bitfield functions at boot.
2542
2543 KUnit tests run during boot and output the results to the debug log
2544 in TAP format (http://testanything.org/). Only useful for kernel devs
2545 running the KUnit test harness, and not intended for inclusion into a
2546 production build.
2547
2548 For more information on KUnit and unit tests in general please refer
2549 to the KUnit documentation in Documentation/dev-tools/kunit/.
2550
2551 If unsure, say N.
2552
688eb819
NG
2553config CHECKSUM_KUNIT
2554 tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2555 depends on KUNIT
2556 default KUNIT_ALL_TESTS
2557 help
2558 Enable this option to test the checksum functions at boot.
2559
2560 KUnit tests run during boot and output the results to the debug log
2561 in TAP format (http://testanything.org/). Only useful for kernel devs
2562 running the KUnit test harness, and not intended for inclusion into a
2563 production build.
2564
2565 For more information on KUnit and unit tests in general please refer
2566 to the KUnit documentation in Documentation/dev-tools/kunit/.
2567
2568 If unsure, say N.
2569
0acc968f
IB
2570config HASH_KUNIT_TEST
2571 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2572 depends on KUNIT
2573 default KUNIT_ALL_TESTS
2574 help
2575 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2576 integer (<linux/hash.h>) hash functions on boot.
2577
2578 KUnit tests run during boot and output the results to the debug log
2579 in TAP format (https://testanything.org/). Only useful for kernel devs
2580 running the KUnit test harness, and not intended for inclusion into a
2581 production build.
2582
2583 For more information on KUnit and unit tests in general please refer
2584 to the KUnit documentation in Documentation/dev-tools/kunit/.
2585
2586 This is intended to help people writing architecture-specific
2587 optimized versions. If unsure, say N.
2588
5df38ca6 2589config RESOURCE_KUNIT_TEST
dcbb2ee2 2590 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
5df38ca6 2591 depends on KUNIT
dcbb2ee2 2592 default KUNIT_ALL_TESTS
5df38ca6
AS
2593 help
2594 This builds the resource API unit test.
2595 Tests the logic of API provided by resource.c and ioport.h.
2596 For more information on KUnit and unit tests in general please refer
2597 to the KUnit documentation in Documentation/dev-tools/kunit/.
2598
2599 If unsure, say N.
2600
2cb80dbb 2601config SYSCTL_KUNIT_TEST
5f215aab 2602 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2cb80dbb 2603 depends on KUNIT
5f215aab 2604 default KUNIT_ALL_TESTS
2cb80dbb
IZ
2605 help
2606 This builds the proc sysctl unit test, which runs on boot.
2607 Tests the API contract and implementation correctness of sysctl.
2608 For more information on KUnit and unit tests in general please refer
2609 to the KUnit documentation in Documentation/dev-tools/kunit/.
2610
2611 If unsure, say N.
2612
ea2dd7c0 2613config LIST_KUNIT_TEST
5f215aab 2614 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
ea2dd7c0 2615 depends on KUNIT
5f215aab 2616 default KUNIT_ALL_TESTS
ea2dd7c0
DG
2617 help
2618 This builds the linked list KUnit test suite.
2619 It tests that the API and basic functionality of the list_head type
2620 and associated macros.
2621
2622 KUnit tests run during boot and output the results to the debug log
d89775fc 2623 in TAP format (https://testanything.org/). Only useful for kernel devs
ea2dd7c0
DG
2624 running the KUnit test harness, and not intended for inclusion into a
2625 production build.
2626
2627 For more information on KUnit and unit tests in general please refer
2628 to the KUnit documentation in Documentation/dev-tools/kunit/.
2629
2630 If unsure, say N.
2631
789538c6
RM
2632config HASHTABLE_KUNIT_TEST
2633 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2634 depends on KUNIT
2635 default KUNIT_ALL_TESTS
2636 help
2637 This builds the hashtable KUnit test suite.
2638 It tests the basic functionality of the API defined in
2639 include/linux/hashtable.h. For more information on KUnit and
2640 unit tests in general please refer to the KUnit documentation
2641 in Documentation/dev-tools/kunit/.
2642
2643 If unsure, say N.
2644
33d599f0
MV
2645config LINEAR_RANGES_TEST
2646 tristate "KUnit test for linear_ranges"
2647 depends on KUNIT
2648 select LINEAR_RANGES
2649 help
2650 This builds the linear_ranges unit test, which runs on boot.
2651 Tests the linear_ranges logic correctness.
2652 For more information on KUnit and unit tests in general please refer
7546861a
AS
2653 to the KUnit documentation in Documentation/dev-tools/kunit/.
2654
2655 If unsure, say N.
2656
2657config CMDLINE_KUNIT_TEST
dcbb2ee2 2658 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
7546861a 2659 depends on KUNIT
dcbb2ee2 2660 default KUNIT_ALL_TESTS
7546861a
AS
2661 help
2662 This builds the cmdline API unit test.
2663 Tests the logic of API provided by cmdline.c.
2664 For more information on KUnit and unit tests in general please refer
33d599f0
MV
2665 to the KUnit documentation in Documentation/dev-tools/kunit/.
2666
2667 If unsure, say N.
2668
6d511020 2669config BITS_TEST
dcbb2ee2 2670 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
6d511020 2671 depends on KUNIT
dcbb2ee2 2672 default KUNIT_ALL_TESTS
6d511020
RF
2673 help
2674 This builds the bits unit test.
2675 Tests the logic of macros defined in bits.h.
2676 For more information on KUnit and unit tests in general please refer
2677 to the KUnit documentation in Documentation/dev-tools/kunit/.
2678
2679 If unsure, say N.
2680
1f9f78b1
OG
2681config SLUB_KUNIT_TEST
2682 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2683 depends on SLUB_DEBUG && KUNIT
2684 default KUNIT_ALL_TESTS
2685 help
2686 This builds SLUB allocator unit test.
2687 Tests SLUB cache debugging functionality.
2688 For more information on KUnit and unit tests in general please refer
2689 to the KUnit documentation in Documentation/dev-tools/kunit/.
2690
2691 If unsure, say N.
2692
b6c75c4a
TP
2693config RATIONAL_KUNIT_TEST
2694 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
8ba739ed 2695 depends on KUNIT && RATIONAL
b6c75c4a
TP
2696 default KUNIT_ALL_TESTS
2697 help
2698 This builds the rational math unit test.
2699 For more information on KUnit and unit tests in general please refer
2700 to the KUnit documentation in Documentation/dev-tools/kunit/.
2701
2702 If unsure, say N.
2703
bb95ebbe
KC
2704config MEMCPY_KUNIT_TEST
2705 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2706 depends on KUNIT
2707 default KUNIT_ALL_TESTS
2708 help
2709 Builds unit tests for memcpy(), memmove(), and memset() functions.
2710 For more information on KUnit and unit tests in general please refer
2711 to the KUnit documentation in Documentation/dev-tools/kunit/.
2712
2713 If unsure, say N.
2714
4acf1de3
KC
2715config MEMCPY_SLOW_KUNIT_TEST
2716 bool "Include exhaustive memcpy tests"
2717 depends on MEMCPY_KUNIT_TEST
2718 default y
2719 help
2720 Some memcpy tests are quite exhaustive in checking for overlaps
2721 and bit ranges. These can be very slow, so they are split out
2722 as a separate config, in case they need to be disabled.
2723
d055c6a2
RM
2724 Note this config option will be replaced by the use of KUnit test
2725 attributes.
2726
addbeea6
BVA
2727config IS_SIGNED_TYPE_KUNIT_TEST
2728 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2729 depends on KUNIT
2730 default KUNIT_ALL_TESTS
2731 help
2732 Builds unit tests for the is_signed_type() macro.
2733
2734 For more information on KUnit and unit tests in general please refer
2735 to the KUnit documentation in Documentation/dev-tools/kunit/.
2736
2737 If unsure, say N.
2738
617f55e2
KC
2739config OVERFLOW_KUNIT_TEST
2740 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2741 depends on KUNIT
2742 default KUNIT_ALL_TESTS
2743 help
2744 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2745 related functions.
2746
2747 For more information on KUnit and unit tests in general please refer
2748 to the KUnit documentation in Documentation/dev-tools/kunit/.
2749
2750 If unsure, say N.
2751
02788ebc
KC
2752config STACKINIT_KUNIT_TEST
2753 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2754 depends on KUNIT
2755 default KUNIT_ALL_TESTS
2756 help
2757 Test if the kernel is zero-initializing stack variables and
2758 padding. Coverage is controlled by compiler flags,
2759 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2760 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2761 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2762
875bfd52
KC
2763config FORTIFY_KUNIT_TEST
2764 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
5e2956ee 2765 depends on KUNIT && FORTIFY_SOURCE
875bfd52
KC
2766 default KUNIT_ALL_TESTS
2767 help
2768 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2769 by the str*() and mem*() family of functions. For testing runtime
2770 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2771
724c299c
ME
2772config HW_BREAKPOINT_KUNIT_TEST
2773 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2774 depends on HAVE_HW_BREAKPOINT
2775 depends on KUNIT=y
2776 default KUNIT_ALL_TESTS
2777 help
2778 Tests for hw_breakpoint constraints accounting.
2779
2780 If unsure, say N.
2781
3bf301e1
KC
2782config STRCAT_KUNIT_TEST
2783 tristate "Test strcat() family of functions at runtime" if !KUNIT_ALL_TESTS
2784 depends on KUNIT
2785 default KUNIT_ALL_TESTS
2786
41eefc46
KC
2787config STRSCPY_KUNIT_TEST
2788 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2789 depends on KUNIT
2790 default KUNIT_ALL_TESTS
2791
fb3d88ab
KC
2792config SIPHASH_KUNIT_TEST
2793 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2794 depends on KUNIT
2795 default KUNIT_ALL_TESTS
2796 help
2797 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2798 functions on boot (or module load).
2799
2800 This is intended to help people writing architecture-specific
2801 optimized versions. If unsure, say N.
2802
e704f93a
DR
2803config TEST_UDELAY
2804 tristate "udelay test driver"
e704f93a
DR
2805 help
2806 This builds the "udelay_test" module that helps to make sure
2807 that udelay() is working properly.
2808
2809 If unsure, say N.
2810
2bf9e0ab
IM
2811config TEST_STATIC_KEYS
2812 tristate "Test static keys"
579e1acb
JB
2813 depends on m
2814 help
2bf9e0ab 2815 Test the static key interfaces.
579e1acb
JB
2816
2817 If unsure, say N.
2818
683263a5
JC
2819config TEST_DYNAMIC_DEBUG
2820 tristate "Test DYNAMIC_DEBUG"
2821 depends on DYNAMIC_DEBUG
2822 help
2823 This module registers a tracer callback to count enabled
2824 pr_debugs in a 'do_debugging' function, then alters their
2825 enablements, calls the function, and compares counts.
2826
2827 If unsure, say N.
2828
d9c6a72d
LR
2829config TEST_KMOD
2830 tristate "kmod stress tester"
d9c6a72d 2831 depends on m
d9c6a72d 2832 depends on NETDEVICES && NET_CORE && INET # for TUN
ae3d6a32 2833 depends on BLOCK
bbd2e05f 2834 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
d9c6a72d
LR
2835 select TEST_LKM
2836 select XFS_FS
2837 select TUN
2838 select BTRFS_FS
2839 help
2840 Test the kernel's module loading mechanism: kmod. kmod implements
2841 support to load modules using the Linux kernel's usermode helper.
2842 This test provides a series of tests against kmod.
2843
2844 Although technically you can either build test_kmod as a module or
2845 into the kernel we disallow building it into the kernel since
2846 it stress tests request_module() and this will very likely cause
2847 some issues by taking over precious threads available from other
2848 module load requests, ultimately this could be fatal.
2849
2850 To run tests run:
2851
2852 tools/testing/selftests/kmod/kmod.sh --help
2853
2854 If unsure, say N.
2855
e4dace36
FF
2856config TEST_DEBUG_VIRTUAL
2857 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2858 depends on DEBUG_VIRTUAL
2859 help
2860 Test the kernel's ability to detect incorrect calls to
2861 virt_to_phys() done against the non-linear part of the
2862 kernel's virtual address map.
2863
2864 If unsure, say N.
2865
ce76d938
AS
2866config TEST_MEMCAT_P
2867 tristate "Test memcat_p() helper function"
2868 help
2869 Test the memcat_p() helper for correctly merging two
2870 pointer arrays together.
2871
2872 If unsure, say N.
2873
a2818ee4
JL
2874config TEST_LIVEPATCH
2875 tristate "Test livepatching"
2876 default n
bae05437 2877 depends on DYNAMIC_DEBUG
a2818ee4
JL
2878 depends on LIVEPATCH
2879 depends on m
2880 help
2881 Test kernel livepatching features for correctness. The tests will
2882 load test modules that will be livepatched in various scenarios.
2883
2884 To run all the livepatching tests:
2885
2886 make -C tools/testing/selftests TARGETS=livepatch run_tests
2887
2888 Alternatively, individual tests may be invoked:
2889
2890 tools/testing/selftests/livepatch/test-callbacks.sh
2891 tools/testing/selftests/livepatch/test-livepatch.sh
2892 tools/testing/selftests/livepatch/test-shadow-vars.sh
2893
2894 If unsure, say N.
2895
0a020d41
JP
2896config TEST_OBJAGG
2897 tristate "Perform selftest on object aggreration manager"
2898 default n
2899 depends on OBJAGG
2900 help
2901 Enable this option to test object aggregation manager on boot
2902 (or module load).
2903
5015a300
AP
2904config TEST_MEMINIT
2905 tristate "Test heap/page initialization"
2906 help
2907 Test if the kernel is zero-initializing heap and page allocations.
2908 This can be useful to test init_on_alloc and init_on_free features.
2909
2910 If unsure, say N.
2911
b2ef9f5a
RC
2912config TEST_HMM
2913 tristate "Test HMM (Heterogeneous Memory Management)"
2914 depends on TRANSPARENT_HUGEPAGE
2915 depends on DEVICE_PRIVATE
2916 select HMM_MIRROR
2917 select MMU_NOTIFIER
2918 help
2919 This is a pseudo device driver solely for testing HMM.
2920 Say M here if you want to build the HMM test module.
2921 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2922
2923 If unsure, say N.
2924
e320d301
MWO
2925config TEST_FREE_PAGES
2926 tristate "Test freeing pages"
2927 help
2928 Test that a memory leak does not occur due to a race between
2929 freeing a block of pages and a speculative page reference.
2930 Loading this module is safe if your kernel has the bug fixed.
2931 If the bug is not fixed, it will leak gigabytes of memory and
2932 probably OOM your system.
2933
4185b3b9
PA
2934config TEST_FPU
2935 tristate "Test floating point operations in kernel space"
2936 depends on X86 && !KCOV_INSTRUMENT_ALL
2937 help
2938 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2939 which will trigger a sequence of floating point operations. This is used
2940 for self-testing floating point control register setting in
2941 kernel_fpu_begin().
2942
2943 If unsure, say N.
2944
1253b9b8
PM
2945config TEST_CLOCKSOURCE_WATCHDOG
2946 tristate "Test clocksource watchdog in kernel space"
2947 depends on CLOCKSOURCE_WATCHDOG
2948 help
2949 Enable this option to create a kernel module that will trigger
2950 a test of the clocksource watchdog. This module may be loaded
2951 via modprobe or insmod in which case it will run upon being
2952 loaded, or it may be built in, in which case it will run
2953 shortly after boot.
2954
2955 If unsure, say N.
2956
92f90d3b 2957config TEST_OBJPOOL
2958 tristate "Test module for correctness and stress of objpool"
2959 default n
2960 depends on m && DEBUG_KERNEL
2961 help
2962 This builds the "test_objpool" module that should be used for
2963 correctness verification and concurrent testings of objects
2964 allocation and reclamation.
2965
2966 If unsure, say N.
2967
d3deafaa 2968endif # RUNTIME_TESTING_MENU
cc3fa840 2969
dce44566
AK
2970config ARCH_USE_MEMTEST
2971 bool
2972 help
2973 An architecture should select this when it uses early_memtest()
2974 during boot process.
2975
cc3fa840
RD
2976config MEMTEST
2977 bool "Memtest"
dce44566 2978 depends on ARCH_USE_MEMTEST
a7f7f624 2979 help
cc3fa840 2980 This option adds a kernel parameter 'memtest', which allows memtest
dce44566 2981 to be set and executed.
cc3fa840
RD
2982 memtest=0, mean disabled; -- default
2983 memtest=1, mean do 1 test pattern;
2984 ...
2985 memtest=17, mean do 17 test patterns.
2986 If you are unsure how to answer this question, answer N.
2987
21266be9 2988
06ec64b8 2989
af9ca6f9
BB
2990config HYPERV_TESTING
2991 bool "Microsoft Hyper-V driver testing"
2992 default n
2993 depends on HYPERV && DEBUG_FS
2994 help
2995 Select this option to enable Hyper-V vmbus testing.
2996
045f6d79
CD
2997endmenu # "Kernel Testing and Coverage"
2998
2f7ab126
MO
2999menu "Rust hacking"
3000
3001config RUST_DEBUG_ASSERTIONS
3002 bool "Debug assertions"
3003 depends on RUST
3004 help
3005 Enables rustc's `-Cdebug-assertions` codegen option.
3006
3007 This flag lets you turn `cfg(debug_assertions)` conditional
3008 compilation on or off. This can be used to enable extra debugging
3009 code in development but not in production. For example, it controls
3010 the behavior of the standard library's `debug_assert!` macro.
3011
3012 Note that this will apply to all Rust code, including `core`.
3013
3014 If unsure, say N.
3015
3016config RUST_OVERFLOW_CHECKS
3017 bool "Overflow checks"
3018 default y
3019 depends on RUST
3020 help
3021 Enables rustc's `-Coverflow-checks` codegen option.
3022
3023 This flag allows you to control the behavior of runtime integer
3024 overflow. When overflow-checks are enabled, a Rust panic will occur
3025 on overflow.
3026
3027 Note that this will apply to all Rust code, including `core`.
3028
3029 If unsure, say Y.
3030
ecaa6ddf
GG
3031config RUST_BUILD_ASSERT_ALLOW
3032 bool "Allow unoptimized build-time assertions"
3033 depends on RUST
3034 help
3035 Controls how are `build_error!` and `build_assert!` handled during build.
3036
3037 If calls to them exist in the binary, it may indicate a violated invariant
3038 or that the optimizer failed to verify the invariant during compilation.
3039
3040 This should not happen, thus by default the build is aborted. However,
3041 as an escape hatch, you can choose Y here to ignore them during build
3042 and let the check be carried at runtime (with `panic!` being called if
3043 the check fails).
3044
3045 If unsure, say N.
3046
a66d733d
MO
3047config RUST_KERNEL_DOCTESTS
3048 bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
3049 depends on RUST && KUNIT=y
3050 default KUNIT_ALL_TESTS
3051 help
3052 This builds the documentation tests of the `kernel` crate
3053 as KUnit tests.
3054
3055 For more information on KUnit and unit tests in general,
3056 please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
3057
3058 If unsure, say N.
3059
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3060endmenu # "Rust"
3061
06ec64b8 3062endmenu # Kernel hacking