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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 help
359 Generate debug info into separate .dwo files. This significantly
360 reduces the build directory size for builds with DEBUG_INFO,
361 because it stores the information only once on disk in .dwo
362 files instead of multiple times in object files and executables.
363 In addition the debug information is also compressed.
364
365 Requires recent gcc (4.7+) and recent gdb/binutils.
366 Any tool that packages or reads debug information would need
367 to know about the .dwo files and include them.
368 Incompatible with older versions of ccache.
369
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370config DEBUG_INFO_BTF
371 bool "Generate BTF typeinfo"
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372 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
373 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
d9847eb8 374 depends on BPF_SYSCALL
52deda95 375 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
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376 help
377 Generate deduplicated BTF type information from DWARF debug info.
378 Turning this on expects presence of pahole tool, which will convert
379 DWARF type info into equivalent deduplicated BTF type info.
380
5f9ae91f 381config PAHOLE_HAS_SPLIT_BTF
6323c813 382 def_bool PAHOLE_VERSION >= 119
5f9ae91f 383
7472d5a6 384config PAHOLE_HAS_BTF_TAG
6323c813 385 def_bool PAHOLE_VERSION >= 123
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386 depends on CC_IS_CLANG
387 help
388 Decide whether pahole emits btf_tag attributes (btf_type_tag and
389 btf_decl_tag) or not. Currently only clang compiler implements
390 these attributes, so make the config depend on CC_IS_CLANG.
5f9ae91f 391
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392config PAHOLE_HAS_LANG_EXCLUDE
393 def_bool PAHOLE_VERSION >= 124
394 help
395 Support for the --lang_exclude flag which makes pahole exclude
396 compilation units from the supplied language. Used in Kbuild to
397 omit Rust CUs which are not supported in version 1.24 of pahole,
398 otherwise it would emit malformed kernel and module binaries when
399 using DEBUG_INFO_BTF_MODULES.
400
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401config DEBUG_INFO_BTF_MODULES
402 def_bool y
403 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
404 help
405 Generate compact split BTF type information for kernel modules.
406
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407config MODULE_ALLOW_BTF_MISMATCH
408 bool "Allow loading modules with non-matching BTF type info"
409 depends on DEBUG_INFO_BTF_MODULES
410 help
411 For modules whose split BTF does not match vmlinux, load without
412 BTF rather than refusing to load. The default behavior with
413 module BTF enabled is to reject modules with such mismatches;
414 this option will still load module BTF where possible but ignore
415 it when a mismatch is found.
416
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417config GDB_SCRIPTS
418 bool "Provide GDB scripts for kernel debugging"
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419 help
420 This creates the required links to GDB helper scripts in the
421 build directory. If you load vmlinux into gdb, the helper
422 scripts will be automatically imported by gdb as well, and
423 additional functions are available to analyze a Linux kernel
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424 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
425 for further details.
3ee7b3fa 426
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427endif # DEBUG_INFO
428
35bb5b1e 429config FRAME_WARN
a83e4ca2 430 int "Warn for stack frames larger than"
35bb5b1e 431 range 0 8192
ac66998d 432 default 0 if KMSAN
0e07f663 433 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
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434 default 2048 if PARISC
435 default 1536 if (!64BIT && XTENSA)
152fe65f 436 default 1280 if KASAN && !64BIT
8d192bec 437 default 1024 if !64BIT
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438 default 2048 if 64BIT
439 help
921757bc 440 Tell the compiler to warn at build time for stack frames larger than this.
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441 Setting this too low will cause a lot of warnings.
442 Setting it to 0 disables the warning.
35bb5b1e 443
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444config STRIP_ASM_SYMS
445 bool "Strip assembler-generated symbols during link"
446 default n
447 help
448 Strip internal assembler-generated symbols during a link (symbols
449 that look like '.Lxxx') so they don't pollute the output of
450 get_wchan() and suchlike.
451
1873e870 452config READABLE_ASM
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453 bool "Generate readable assembler code"
454 depends on DEBUG_KERNEL
7d73c3e9 455 depends on CC_IS_GCC
bf4735a4 456 help
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457 Disable some compiler optimizations that tend to generate human unreadable
458 assembler output. This may make the kernel slightly slower, but it helps
459 to keep kernel developers who have to stare a lot at assembler listings
460 sane.
bf4735a4 461
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462config HEADERS_INSTALL
463 bool "Install uapi headers to usr/include"
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464 depends on !UML
465 help
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466 This option will install uapi headers (headers exported to user-space)
467 into the usr/include directory for use during the kernel build.
468 This is unneeded for building the kernel itself, but needed for some
469 user-space program samples. It is also needed by some features such
470 as uapi header sanity checks.
471
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472config DEBUG_SECTION_MISMATCH
473 bool "Enable full Section mismatch analysis"
7d73c3e9 474 depends on CC_IS_GCC
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475 help
476 The section mismatch analysis checks if there are illegal
477 references from one section to another section.
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478 During linktime or runtime, some sections are dropped;
479 any use of code/data previously in these sections would
91341d4b 480 most likely result in an oops.
e809ab01 481 In the code, functions and variables are annotated with
0db0628d 482 __init,, etc. (see the full list in include/linux/init.h),
d6fbfa4f 483 which results in the code/data being placed in specific sections.
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484 The section mismatch analysis is always performed after a full
485 kernel build, and enabling this option causes the following
b7dca6dd 486 additional step to occur:
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487 - Add the option -fno-inline-functions-called-once to gcc commands.
488 When inlining a function annotated with __init in a non-init
489 function, we would lose the section information and thus
91341d4b 490 the analysis would not catch the illegal reference.
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491 This option tells gcc to inline less (but it does result in
492 a larger kernel).
91341d4b 493
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494config SECTION_MISMATCH_WARN_ONLY
495 bool "Make section mismatch errors non-fatal"
496 default y
497 help
498 If you say N here, the build process will fail if there are any
499 section mismatch, instead of just throwing warnings.
500
501 If unsure, say Y.
502
cf536e18 503config DEBUG_FORCE_FUNCTION_ALIGN_64B
1bf18da6 504 bool "Force all function address 64B aligned"
322a7ce7 505 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || S390)
d49a0626 506 select FUNCTION_ALIGNMENT_64B
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507 help
508 There are cases that a commit from one domain changes the function
509 address alignment of other domains, and cause magic performance
510 bump (regression or improvement). Enable this option will help to
511 verify if the bump is caused by function alignment changes, while
512 it will slightly increase the kernel size and affect icache usage.
513
514 It is mainly for debug and performance tuning use.
515
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516#
517# Select this config option from the architecture Kconfig, if it
518# is preferred to always offer frame pointers as a config
519# option on the architecture (regardless of KERNEL_DEBUG):
520#
521config ARCH_WANT_FRAME_POINTERS
522 bool
f346f4b3 523
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524config FRAME_POINTER
525 bool "Compile the kernel with frame pointers"
a687a533 526 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
6dfc0665 527 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
a304e1b8 528 help
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529 If you say Y here the resulting kernel image will be slightly
530 larger and slower, but it gives very useful debugging information
531 in case of kernel bugs. (precise oopses/stacktraces/warnings)
a304e1b8 532
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533config OBJTOOL
534 bool
535
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536config STACK_VALIDATION
537 bool "Compile-time stack metadata validation"
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538 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
539 select OBJTOOL
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540 default n
541 help
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542 Validate frame pointer rules at compile-time. This helps ensure that
543 runtime stack traces are more reliable.
ee9f8fce 544
b9ab5ebb 545 For more information, see
d6a21f2d 546 tools/objtool/Documentation/objtool.txt.
b9ab5ebb 547
0f620cef 548config NOINSTR_VALIDATION
6804c1af 549 bool
489e355b 550 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
03f16cd0 551 select OBJTOOL
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552 default y
553
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554config VMLINUX_MAP
555 bool "Generate vmlinux.map file when linking"
556 depends on EXPERT
557 help
558 Selecting this option will pass "-Map=vmlinux.map" to ld
559 when linking vmlinux. That file can be useful for verifying
560 and debugging magic section games, and for seeing which
561 pieces of code get eliminated with
562 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
563
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564config DEBUG_FORCE_WEAK_PER_CPU
565 bool "Force weak per-cpu definitions"
566 depends on DEBUG_KERNEL
8446f1d3 567 help
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568 s390 and alpha require percpu variables in modules to be
569 defined weak to work around addressing range issue which
570 puts the following two restrictions on percpu variable
571 definitions.
8446f1d3 572
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573 1. percpu symbols must be unique whether static or not
574 2. percpu variables can't be defined inside a function
8446f1d3 575
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576 To ensure that generic code follows the above rules, this
577 option forces all percpu variables to be defined as weak.
5f329089 578
6dfc0665 579endmenu # "Compiler options"
8446f1d3 580
6210b640
CD
581menu "Generic Kernel Debugging Instruments"
582
6dfc0665
DH
583config MAGIC_SYSRQ
584 bool "Magic SysRq key"
585 depends on !UML
586 help
587 If you say Y here, you will have some control over the system even
588 if the system crashes for example during kernel debugging (e.g., you
589 will be able to flush the buffer cache to disk, reboot the system
590 immediately or dump some status information). This is accomplished
591 by pressing various keys while holding SysRq (Alt+PrintScreen). It
592 also works on a serial console (on PC hardware at least), if you
593 send a BREAK and then within 5 seconds a command keypress. The
f8998c22
HH
594 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
595 Don't say Y unless you really know what this hack does.
8446f1d3 596
8eaede49
BH
597config MAGIC_SYSRQ_DEFAULT_ENABLE
598 hex "Enable magic SysRq key functions by default"
599 depends on MAGIC_SYSRQ
600 default 0x1
601 help
602 Specifies which SysRq key functions are enabled by default.
603 This may be set to 1 or 0 to enable or disable them all, or
f8998c22 604 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
8eaede49 605
732dbf3a
FF
606config MAGIC_SYSRQ_SERIAL
607 bool "Enable magic SysRq key over serial"
608 depends on MAGIC_SYSRQ
609 default y
610 help
611 Many embedded boards have a disconnected TTL level serial which can
612 generate some garbage that can lead to spurious false sysrq detects.
613 This option allows you to decide whether you want to enable the
614 magic SysRq key.
615
68af4317
DS
616config MAGIC_SYSRQ_SERIAL_SEQUENCE
617 string "Char sequence that enables magic SysRq over serial"
618 depends on MAGIC_SYSRQ_SERIAL
619 default ""
620 help
621 Specifies a sequence of characters that can follow BREAK to enable
622 SysRq on a serial console.
623
d3394b3d
DS
624 If unsure, leave an empty string and the option will not be enabled.
625
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CD
626config DEBUG_FS
627 bool "Debug Filesystem"
628 help
629 debugfs is a virtual file system that kernel developers use to put
630 debugging files into. Enable this option to be able to read and
631 write to these files.
632
633 For detailed documentation on the debugfs API, see
634 Documentation/filesystems/.
635
636 If unsure, say N.
637
a24c6f7b
PE
638choice
639 prompt "Debugfs default access"
640 depends on DEBUG_FS
641 default DEBUG_FS_ALLOW_ALL
642 help
643 This selects the default access restrictions for debugfs.
644 It can be overridden with kernel command line option
645 debugfs=[on,no-mount,off]. The restrictions apply for API access
646 and filesystem registration.
647
648config DEBUG_FS_ALLOW_ALL
649 bool "Access normal"
650 help
651 No restrictions apply. Both API and filesystem registration
652 is on. This is the normal default operation.
653
654config DEBUG_FS_DISALLOW_MOUNT
655 bool "Do not register debugfs as filesystem"
656 help
657 The API is open but filesystem is not loaded. Clients can still do
658 their work and read with debug tools that do not need
659 debugfs filesystem.
660
661config DEBUG_FS_ALLOW_NONE
662 bool "No access"
663 help
664 Access is off. Clients get -PERM when trying to create nodes in
665 debugfs tree and debugfs is not registered as a filesystem.
666 Client can then back-off or continue without debugfs access.
667
668endchoice
669
6210b640 670source "lib/Kconfig.kgdb"
6210b640 671source "lib/Kconfig.ubsan"
2645d432 672source "lib/Kconfig.kcsan"
6210b640
CD
673
674endmenu
675
4d92b95f
ED
676menu "Networking Debugging"
677
678source "net/Kconfig.debug"
679
680endmenu # "Networking Debugging"
c66d7a27 681
0610c8a8 682menu "Memory Debugging"
fef2c9bc 683
8636a1f9 684source "mm/Kconfig.debug"
fef2c9bc 685
0610c8a8
DH
686config DEBUG_OBJECTS
687 bool "Debug object operations"
688 depends on DEBUG_KERNEL
9c44bc03 689 help
0610c8a8
DH
690 If you say Y here, additional code will be inserted into the
691 kernel to track the life time of various objects and validate
692 the operations on those objects.
9c44bc03 693
0610c8a8
DH
694config DEBUG_OBJECTS_SELFTEST
695 bool "Debug objects selftest"
696 depends on DEBUG_OBJECTS
697 help
698 This enables the selftest of the object debug code.
9c44bc03 699
0610c8a8
DH
700config DEBUG_OBJECTS_FREE
701 bool "Debug objects in freed memory"
702 depends on DEBUG_OBJECTS
703 help
704 This enables checks whether a k/v free operation frees an area
705 which contains an object which has not been deactivated
706 properly. This can make kmalloc/kfree-intensive workloads
707 much slower.
3ac7fe5a 708
c6f3a97f
TG
709config DEBUG_OBJECTS_TIMERS
710 bool "Debug timer objects"
711 depends on DEBUG_OBJECTS
712 help
713 If you say Y here, additional code will be inserted into the
714 timer routines to track the life time of timer objects and
715 validate the timer operations.
716
dc186ad7
TG
717config DEBUG_OBJECTS_WORK
718 bool "Debug work objects"
719 depends on DEBUG_OBJECTS
720 help
721 If you say Y here, additional code will be inserted into the
722 work queue routines to track the life time of work objects and
723 validate the work operations.
724
551d55a9
MD
725config DEBUG_OBJECTS_RCU_HEAD
726 bool "Debug RCU callbacks objects"
fc2ecf7e 727 depends on DEBUG_OBJECTS
551d55a9
MD
728 help
729 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
730
e2852ae8
TH
731config DEBUG_OBJECTS_PERCPU_COUNTER
732 bool "Debug percpu counter objects"
733 depends on DEBUG_OBJECTS
734 help
735 If you say Y here, additional code will be inserted into the
736 percpu counter routines to track the life time of percpu counter
737 objects and validate the percpu counter operations.
738
3ae70205
IM
739config DEBUG_OBJECTS_ENABLE_DEFAULT
740 int "debug_objects bootup default value (0-1)"
68d4b3df
KK
741 range 0 1
742 default "1"
743 depends on DEBUG_OBJECTS
744 help
745 Debug objects boot parameter default value
3ae70205 746
5035ebc6 747config SHRINKER_DEBUG
5035ebc6
RG
748 bool "Enable shrinker debugging support"
749 depends on DEBUG_FS
750 help
751 Say Y to enable the shrinker debugfs interface which provides
752 visibility into the kernel memory shrinkers subsystem.
753 Disable it to avoid an extra memory footprint.
754
0610c8a8
DH
755config DEBUG_STACK_USAGE
756 bool "Stack utilization instrumentation"
6c31da34 757 depends on DEBUG_KERNEL && !IA64
0610c8a8
DH
758 help
759 Enables the display of the minimum amount of free stack which each
760 task has ever had available in the sysrq-T and sysrq-P debug output.
761
762 This option will slow down process creation somewhat.
763
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CD
764config SCHED_STACK_END_CHECK
765 bool "Detect stack corruption on calls to schedule()"
766 depends on DEBUG_KERNEL
767 default n
768 help
769 This option checks for a stack overrun on calls to schedule().
770 If the stack end location is found to be over written always panic as
771 the content of the corrupted region can no longer be trusted.
772 This is to ensure no erroneous behaviour occurs which could result in
773 data corruption or a sporadic crash at a later stage once the region
774 is examined. The runtime overhead introduced is minimal.
775
399145f9
AK
776config ARCH_HAS_DEBUG_VM_PGTABLE
777 bool
778 help
779 An architecture should select this when it can successfully
780 build and run DEBUG_VM_PGTABLE.
781
a738e9ba
TG
782config DEBUG_VM_IRQSOFF
783 def_bool DEBUG_VM && !PREEMPT_RT
784
0610c8a8
DH
785config DEBUG_VM
786 bool "Debug VM"
787 depends on DEBUG_KERNEL
788 help
789 Enable this to turn on extended checks in the virtual-memory system
68d4b3df 790 that may impact performance.
0610c8a8
DH
791
792 If unsure, say N.
793
2655421a
NP
794config DEBUG_VM_SHOOT_LAZIES
795 bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
796 depends on DEBUG_VM
797 depends on MMU_LAZY_TLB_SHOOTDOWN
798 help
799 Enable additional IPIs that ensure lazy tlb mm references are removed
800 before the mm is freed.
801
802 If unsure, say N.
803
54a611b6
LH
804config DEBUG_VM_MAPLE_TREE
805 bool "Debug VM maple trees"
4f115147 806 depends on DEBUG_VM
54a611b6 807 select DEBUG_MAPLE_TREE
4f115147 808 help
54a611b6 809 Enable VM maple tree debugging information and extra validations.
4f115147
DB
810
811 If unsure, say N.
812
0610c8a8
DH
813config DEBUG_VM_RB
814 bool "Debug VM red-black trees"
815 depends on DEBUG_VM
816 help
a663dad6 817 Enable VM red-black tree debugging information and extra validations.
0610c8a8
DH
818
819 If unsure, say N.
820
95ad9755
KS
821config DEBUG_VM_PGFLAGS
822 bool "Debug page-flags operations"
823 depends on DEBUG_VM
824 help
825 Enables extra validation on page flags operations.
826
827 If unsure, say N.
828
399145f9
AK
829config DEBUG_VM_PGTABLE
830 bool "Debug arch page table for semantics compliance"
831 depends on MMU
832 depends on ARCH_HAS_DEBUG_VM_PGTABLE
833 default y if DEBUG_VM
834 help
835 This option provides a debug method which can be used to test
836 architecture page table helper functions on various platforms in
837 verifying if they comply with expected generic MM semantics. This
838 will help architecture code in making sure that any changes or
839 new additions of these helpers still conform to expected
840 semantics of the generic MM. Platforms will have to opt in for
841 this through ARCH_HAS_DEBUG_VM_PGTABLE.
842
843 If unsure, say N.
844
fa5b6ec9
LA
845config ARCH_HAS_DEBUG_VIRTUAL
846 bool
847
0610c8a8
DH
848config DEBUG_VIRTUAL
849 bool "Debug VM translations"
fa5b6ec9 850 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
0610c8a8
DH
851 help
852 Enable some costly sanity checks in virtual to page code. This can
853 catch mistakes with virt_to_page() and friends.
854
855 If unsure, say N.
856
857config DEBUG_NOMMU_REGIONS
858 bool "Debug the global anon/private NOMMU mapping region tree"
859 depends on DEBUG_KERNEL && !MMU
860 help
861 This option causes the global tree of anonymous and private mapping
862 regions to be regularly checked for invalid topology.
863
864config DEBUG_MEMORY_INIT
865 bool "Debug memory initialisation" if EXPERT
866 default !EXPERT
867 help
868 Enable this for additional checks during memory initialisation.
869 The sanity checks verify aspects of the VM such as the memory model
870 and other information provided by the architecture. Verbose
871 information will be printed at KERN_DEBUG loglevel depending
872 on the mminit_loglevel= command-line option.
873
874 If unsure, say Y
875
876config MEMORY_NOTIFIER_ERROR_INJECT
877 tristate "Memory hotplug notifier error injection module"
50f9481e 878 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
0610c8a8
DH
879 help
880 This option provides the ability to inject artificial errors to
881 memory hotplug notifier chain callbacks. It is controlled through
882 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
883
884 If the notifier call chain should be failed with some events
885 notified, write the error code to "actions/<notifier event>/error".
886
887 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
888
889 # cd /sys/kernel/debug/notifier-error-inject/memory
890 # echo -12 > actions/MEM_GOING_OFFLINE/error
891 # echo offline > /sys/devices/system/memory/memoryXXX/state
892 bash: echo: write error: Cannot allocate memory
893
894 To compile this code as a module, choose M here: the module will
895 be called memory-notifier-error-inject.
896
897 If unsure, say N.
898
899config DEBUG_PER_CPU_MAPS
900 bool "Debug access to per_cpu maps"
901 depends on DEBUG_KERNEL
902 depends on SMP
903 help
904 Say Y to verify that the per_cpu map being accessed has
905 been set up. This adds a fair amount of code to kernel memory
906 and decreases performance.
907
908 Say N if unsure.
909
6e799cb6
TG
910config DEBUG_KMAP_LOCAL
911 bool "Debug kmap_local temporary mappings"
912 depends on DEBUG_KERNEL && KMAP_LOCAL
913 help
914 This option enables additional error checking for the kmap_local
915 infrastructure. Disable for production use.
916
0e91a0c6
TG
917config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
918 bool
919
920config DEBUG_KMAP_LOCAL_FORCE_MAP
921 bool "Enforce kmap_local temporary mappings"
922 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
923 select KMAP_LOCAL
924 select DEBUG_KMAP_LOCAL
925 help
926 This option enforces temporary mappings through the kmap_local
927 mechanism for non-highmem pages and on non-highmem systems.
928 Disable this for production systems!
929
0610c8a8
DH
930config DEBUG_HIGHMEM
931 bool "Highmem debugging"
932 depends on DEBUG_KERNEL && HIGHMEM
0e91a0c6 933 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
6e799cb6 934 select DEBUG_KMAP_LOCAL
0610c8a8 935 help
b1357c9f
GU
936 This option enables additional error checking for high memory
937 systems. Disable for production systems.
0610c8a8
DH
938
939config HAVE_DEBUG_STACKOVERFLOW
940 bool
941
942config DEBUG_STACKOVERFLOW
943 bool "Check for stack overflows"
944 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
a7f7f624 945 help
0610c8a8 946 Say Y here if you want to check for overflows of kernel, IRQ
edb0ec07 947 and exception stacks (if your architecture uses them). This
0610c8a8
DH
948 option will show detailed messages if free stack space drops
949 below a certain limit.
950
951 These kinds of bugs usually occur when call-chains in the
952 kernel get too deep, especially when interrupts are
953 involved.
954
955 Use this in cases where you see apparently random memory
956 corruption, especially if it appears in 'struct thread_info'
957
958 If in doubt, say "N".
959
0b24becc 960source "lib/Kconfig.kasan"
0ce20dd8 961source "lib/Kconfig.kfence"
f80be457 962source "lib/Kconfig.kmsan"
0b24becc 963
0610c8a8
DH
964endmenu # "Memory Debugging"
965
a304e1b8
DW
966config DEBUG_SHIRQ
967 bool "Debug shared IRQ handlers"
0244ad00 968 depends on DEBUG_KERNEL
a304e1b8 969 help
0a2fae2a
WS
970 Enable this to generate a spurious interrupt just before a shared
971 interrupt handler is deregistered (generating one when registering
972 is currently disabled). Drivers need to handle this correctly. Some
973 don't and need to be caught.
a304e1b8 974
f43a289d
CD
975menu "Debug Oops, Lockups and Hangs"
976
977config PANIC_ON_OOPS
978 bool "Panic on Oops"
979 help
980 Say Y here to enable the kernel to panic when it oopses. This
981 has the same effect as setting oops=panic on the kernel command
982 line.
983
984 This feature is useful to ensure that the kernel does not do
985 anything erroneous after an oops which could result in data
986 corruption or other issues.
987
988 Say N if unsure.
989
990config PANIC_ON_OOPS_VALUE
991 int
992 range 0 1
993 default 0 if !PANIC_ON_OOPS
994 default 1 if PANIC_ON_OOPS
995
996config PANIC_TIMEOUT
997 int "panic timeout"
998 default 0
999 help
9d5b134f 1000 Set the timeout value (in seconds) until a reboot occurs when
f43a289d
CD
1001 the kernel panics. If n = 0, then we wait forever. A timeout
1002 value n > 0 will wait n seconds before rebooting, while a timeout
1003 value n < 0 will reboot immediately.
92aef8fb 1004
58687acb 1005config LOCKUP_DETECTOR
05a4a952
NP
1006 bool
1007
1008config SOFTLOCKUP_DETECTOR
1009 bool "Detect Soft Lockups"
dea20a3f 1010 depends on DEBUG_KERNEL && !S390
05a4a952 1011 select LOCKUP_DETECTOR
8446f1d3 1012 help
58687acb 1013 Say Y here to enable the kernel to act as a watchdog to detect
05a4a952 1014 soft lockups.
58687acb
DZ
1015
1016 Softlockups are bugs that cause the kernel to loop in kernel
5f329089 1017 mode for more than 20 seconds, without giving other tasks a
58687acb
DZ
1018 chance to run. The current stack trace is displayed upon
1019 detection and the system will stay locked up.
8446f1d3 1020
5f00ae0d
RD
1021config BOOTPARAM_SOFTLOCKUP_PANIC
1022 bool "Panic (Reboot) On Soft Lockups"
1023 depends on SOFTLOCKUP_DETECTOR
1024 help
1025 Say Y here to enable the kernel to panic on "soft lockups",
1026 which are bugs that cause the kernel to loop in kernel
1027 mode for more than 20 seconds (configurable using the watchdog_thresh
1028 sysctl), without giving other tasks a chance to run.
1029
1030 The panic can be used in combination with panic_timeout,
1031 to cause the system to reboot automatically after a
1032 lockup has been detected. This feature is useful for
1033 high-availability systems that have uptime guarantees and
1034 where a lockup must be resolved ASAP.
1035
1036 Say N if unsure.
1037
1356d0b9 1038config HAVE_HARDLOCKUP_DETECTOR_BUDDY
05a4a952 1039 bool
1356d0b9
PM
1040 depends on SMP
1041 default y
05a4a952 1042
7edaeb68 1043#
1356d0b9
PM
1044# Global switch whether to build a hardlockup detector at all. It is available
1045# only when the architecture supports at least one implementation. There are
1046# two exceptions. The hardlockup detector is never enabled on:
7edaeb68 1047#
1356d0b9 1048# s390: it reported many false positives there
05a4a952 1049#
1356d0b9
PM
1050# sparc64: has a custom implementation which is not using the common
1051# hardlockup command line options and sysctl interface.
05a4a952
NP
1052#
1053config HARDLOCKUP_DETECTOR
1054 bool "Detect Hard Lockups"
47f4cb43 1055 depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
a5fcc236 1056 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
1356d0b9
PM
1057 imply HARDLOCKUP_DETECTOR_PERF
1058 imply HARDLOCKUP_DETECTOR_BUDDY
7ca8fe94 1059 imply HARDLOCKUP_DETECTOR_ARCH
05a4a952 1060 select LOCKUP_DETECTOR
4917a25f 1061
05a4a952
NP
1062 help
1063 Say Y here to enable the kernel to act as a watchdog to detect
1064 hard lockups.
1065
58687acb 1066 Hardlockups are bugs that cause the CPU to loop in kernel mode
5f329089 1067 for more than 10 seconds, without letting other interrupts have a
58687acb
DZ
1068 chance to run. The current stack trace is displayed upon detection
1069 and the system will stay locked up.
8446f1d3 1070
1356d0b9
PM
1071#
1072# Note that arch-specific variants are always preferred.
1073#
4917a25f
PM
1074config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1075 bool "Prefer the buddy CPU hardlockup detector"
1356d0b9
PM
1076 depends on HARDLOCKUP_DETECTOR
1077 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
a8992d8a 1078 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
4917a25f
PM
1079 help
1080 Say Y here to prefer the buddy hardlockup detector over the perf one.
1081
1082 With the buddy detector, each CPU uses its softlockup hrtimer
1083 to check that the next CPU is processing hrtimer interrupts by
1084 verifying that a counter is increasing.
1085
1086 This hardlockup detector is useful on systems that don't have
1087 an arch-specific hardlockup detector or if resources needed
1088 for the hardlockup detector are better used for other things.
05a4a952 1089
1f423c90
DA
1090config HARDLOCKUP_DETECTOR_PERF
1091 bool
1356d0b9
PM
1092 depends on HARDLOCKUP_DETECTOR
1093 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
a5fcc236 1094 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1f423c90
DA
1095 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1096
1097config HARDLOCKUP_DETECTOR_BUDDY
1098 bool
1356d0b9
PM
1099 depends on HARDLOCKUP_DETECTOR
1100 depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1101 depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
a5fcc236 1102 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1f423c90
DA
1103 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1104
7ca8fe94
PM
1105config HARDLOCKUP_DETECTOR_ARCH
1106 bool
1107 depends on HARDLOCKUP_DETECTOR
1108 depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1109 help
1110 The arch-specific implementation of the hardlockup detector will
1111 be used.
1112
1356d0b9 1113#
4917a25f
PM
1114# Both the "perf" and "buddy" hardlockup detectors count hrtimer
1115# interrupts. This config enables functions managing this common code.
1356d0b9 1116#
4917a25f
PM
1117config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1118 bool
1119 select SOFTLOCKUP_DETECTOR
1120
7edaeb68
TG
1121#
1122# Enables a timestamp based low pass filter to compensate for perf based
1123# hard lockup detection which runs too fast due to turbo modes.
1124#
1125config HARDLOCKUP_CHECK_TIMESTAMP
1126 bool
1127
fef2c9bc
DZ
1128config BOOTPARAM_HARDLOCKUP_PANIC
1129 bool "Panic (Reboot) On Hard Lockups"
8f1f66ed 1130 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
1131 help
1132 Say Y here to enable the kernel to panic on "hard lockups",
1133 which are bugs that cause the kernel to loop in kernel
5f329089
FLVC
1134 mode with interrupts disabled for more than 10 seconds (configurable
1135 using the watchdog_thresh sysctl).
fef2c9bc
DZ
1136
1137 Say N if unsure.
1138
e162b39a
MSB
1139config DETECT_HUNG_TASK
1140 bool "Detect Hung Tasks"
1141 depends on DEBUG_KERNEL
05a4a952 1142 default SOFTLOCKUP_DETECTOR
e162b39a 1143 help
0610c8a8
DH
1144 Say Y here to enable the kernel to detect "hung tasks",
1145 which are bugs that cause the task to be stuck in
96b03ab8 1146 uninterruptible "D" state indefinitely.
1da177e4 1147
0610c8a8
DH
1148 When a hung task is detected, the kernel will print the
1149 current stack trace (which you should report), but the
1150 task will stay in uninterruptible state. If lockdep is
1151 enabled then all held locks will also be reported. This
1152 feature has negligible overhead.
871751e2 1153
0610c8a8
DH
1154config DEFAULT_HUNG_TASK_TIMEOUT
1155 int "Default timeout for hung task detection (in seconds)"
1156 depends on DETECT_HUNG_TASK
1157 default 120
f0630fff 1158 help
0610c8a8
DH
1159 This option controls the default timeout (in seconds) used
1160 to determine when a task has become non-responsive and should
1161 be considered hung.
f0630fff 1162
0610c8a8
DH
1163 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1164 sysctl or by writing a value to
1165 /proc/sys/kernel/hung_task_timeout_secs.
8ff12cfc 1166
0610c8a8
DH
1167 A timeout of 0 disables the check. The default is two minutes.
1168 Keeping the default should be fine in most cases.
b69ec42b 1169
0610c8a8
DH
1170config BOOTPARAM_HUNG_TASK_PANIC
1171 bool "Panic (Reboot) On Hung Tasks"
1172 depends on DETECT_HUNG_TASK
3bba00d7 1173 help
0610c8a8
DH
1174 Say Y here to enable the kernel to panic on "hung tasks",
1175 which are bugs that cause the kernel to leave a task stuck
1176 in uninterruptible "D" state.
3bba00d7 1177
0610c8a8
DH
1178 The panic can be used in combination with panic_timeout,
1179 to cause the system to reboot automatically after a
1180 hung task has been detected. This feature is useful for
1181 high-availability systems that have uptime guarantees and
1182 where a hung tasks must be resolved ASAP.
bf96d1e3 1183
0610c8a8 1184 Say N if unsure.
bf96d1e3 1185
82607adc
TH
1186config WQ_WATCHDOG
1187 bool "Detect Workqueue Stalls"
1188 depends on DEBUG_KERNEL
1189 help
1190 Say Y here to enable stall detection on workqueues. If a
1191 worker pool doesn't make forward progress on a pending work
1192 item for over a given amount of time, 30s by default, a
1193 warning message is printed along with dump of workqueue
1194 state. This can be configured through kernel parameter
1195 "workqueue.watchdog_thresh" and its sysfs counterpart.
1196
63638450
TH
1197config WQ_CPU_INTENSIVE_REPORT
1198 bool "Report per-cpu work items which hog CPU for too long"
1199 depends on DEBUG_KERNEL
1200 help
1201 Say Y here to enable reporting of concurrency-managed per-cpu work
1202 items that hog CPUs for longer than
1203 workqueue.cpu_intensive_threshold_us. Workqueue automatically
1204 detects and excludes them from concurrency management to prevent
1205 them from stalling other per-cpu work items. Occassional
1206 triggering may not necessarily indicate a problem. Repeated
1207 triggering likely indicates that the work item should be switched
1208 to use an unbound workqueue.
1209
30428ef5
KK
1210config TEST_LOCKUP
1211 tristate "Test module to generate lockups"
63646bc9 1212 depends on m
30428ef5
KK
1213 help
1214 This builds the "test_lockup" module that helps to make sure
1215 that watchdogs and lockup detectors are working properly.
1216
1217 Depending on module parameters it could emulate soft or hard
1218 lockup, "hung task", or locking arbitrary lock for a long time.
1219 Also it could generate series of lockups with cooling-down periods.
1220
1221 If unsure, say N.
1222
92aef8fb
DH
1223endmenu # "Debug lockups and hangs"
1224
ebebdd09 1225menu "Scheduler Debugging"
5800dc3c 1226
0610c8a8
DH
1227config SCHED_DEBUG
1228 bool "Collect scheduler debugging info"
35260cf5 1229 depends on DEBUG_KERNEL && DEBUG_FS
0610c8a8 1230 default y
0822ee4a 1231 help
1e90e35b 1232 If you say Y here, the /sys/kernel/debug/sched file will be provided
0610c8a8
DH
1233 that can help debug the scheduler. The runtime overhead of this
1234 option is minimal.
0822ee4a 1235
f6db8347
NR
1236config SCHED_INFO
1237 bool
1238 default n
1239
0610c8a8
DH
1240config SCHEDSTATS
1241 bool "Collect scheduler statistics"
1242 depends on DEBUG_KERNEL && PROC_FS
f6db8347 1243 select SCHED_INFO
0610c8a8
DH
1244 help
1245 If you say Y here, additional code will be inserted into the
1246 scheduler and related routines to collect statistics about
1247 scheduler behavior and provide them in /proc/schedstat. These
1248 stats may be useful for both tuning and debugging the scheduler
1249 If you aren't debugging the scheduler or trying to tune a specific
1250 application, you can say N to avoid the very slight overhead
1251 this adds.
0822ee4a 1252
ebebdd09 1253endmenu
0d9e2632 1254
3c17ad19
JS
1255config DEBUG_TIMEKEEPING
1256 bool "Enable extra timekeeping sanity checking"
1257 help
1258 This option will enable additional timekeeping sanity checks
1259 which may be helpful when diagnosing issues where timekeeping
1260 problems are suspected.
1261
1262 This may include checks in the timekeeping hotpaths, so this
1263 option may have a (very small) performance impact to some
1264 workloads.
1265
1266 If unsure, say N.
1267
1da177e4
LT
1268config DEBUG_PREEMPT
1269 bool "Debug preemptible kernel"
9f472869 1270 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1da177e4
LT
1271 help
1272 If you say Y here then the kernel will use a debug variant of the
1273 commonly used smp_processor_id() function and will print warnings
1274 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1275 will detect preemption count underflows.
1276
cc600391
HY
1277 This option has potential to introduce high runtime overhead,
1278 depending on workload as it triggers debugging routines for each
1279 this_cpu operation. It should only be used for debugging purposes.
1280
9eade16b
DH
1281menu "Lock Debugging (spinlocks, mutexes, etc...)"
1282
f07cbebb
WL
1283config LOCK_DEBUGGING_SUPPORT
1284 bool
1285 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1286 default y
1287
19193bca
WL
1288config PROVE_LOCKING
1289 bool "Lock debugging: prove locking correctness"
1290 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1291 select LOCKDEP
1292 select DEBUG_SPINLOCK
bb630f9f 1293 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca 1294 select DEBUG_RT_MUTEXES if RT_MUTEXES
c71fd893 1295 select DEBUG_RWSEMS
19193bca
WL
1296 select DEBUG_WW_MUTEX_SLOWPATH
1297 select DEBUG_LOCK_ALLOC
8fd8ad5c 1298 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
19193bca
WL
1299 select TRACE_IRQFLAGS
1300 default n
1301 help
1302 This feature enables the kernel to prove that all locking
1303 that occurs in the kernel runtime is mathematically
1304 correct: that under no circumstance could an arbitrary (and
1305 not yet triggered) combination of observed locking
1306 sequences (on an arbitrary number of CPUs, running an
1307 arbitrary number of tasks and interrupt contexts) cause a
1308 deadlock.
1309
1310 In short, this feature enables the kernel to report locking
1311 related deadlocks before they actually occur.
1312
1313 The proof does not depend on how hard and complex a
1314 deadlock scenario would be to trigger: how many
1315 participant CPUs, tasks and irq-contexts would be needed
1316 for it to trigger. The proof also does not depend on
1317 timing: if a race and a resulting deadlock is possible
1318 theoretically (no matter how unlikely the race scenario
1319 is), it will be proven so and will immediately be
1320 reported by the kernel (once the event is observed that
1321 makes the deadlock theoretically possible).
1322
1323 If a deadlock is impossible (i.e. the locking rules, as
1324 observed by the kernel, are mathematically correct), the
1325 kernel reports nothing.
1326
1327 NOTE: this feature can also be enabled for rwlocks, mutexes
1328 and rwsems - in which case all dependencies between these
1329 different locking variants are observed and mapped too, and
1330 the proof of observed correctness is also maintained for an
1331 arbitrary combination of these separate locking variants.
1332
387b1468 1333 For more details, see Documentation/locking/lockdep-design.rst.
19193bca 1334
de8f5e4f
PZ
1335config PROVE_RAW_LOCK_NESTING
1336 bool "Enable raw_spinlock - spinlock nesting checks"
1337 depends on PROVE_LOCKING
1338 default n
1339 help
1340 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1341 that the lock nesting rules for PREEMPT_RT enabled kernels are
1342 not violated.
1343
1344 NOTE: There are known nesting problems. So if you enable this
1345 option expect lockdep splats until these problems have been fully
1346 addressed which is work in progress. This config switch allows to
1347 identify and analyze these problems. It will be removed and the
9dbbc3b9 1348 check permanently enabled once the main issues have been fixed.
de8f5e4f
PZ
1349
1350 If unsure, select N.
1351
19193bca
WL
1352config LOCK_STAT
1353 bool "Lock usage statistics"
1354 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1355 select LOCKDEP
1356 select DEBUG_SPINLOCK
bb630f9f 1357 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca
WL
1358 select DEBUG_RT_MUTEXES if RT_MUTEXES
1359 select DEBUG_LOCK_ALLOC
1360 default n
1361 help
1362 This feature enables tracking lock contention points
1363
387b1468 1364 For more details, see Documentation/locking/lockstat.rst
19193bca
WL
1365
1366 This also enables lock events required by "perf lock",
1367 subcommand of perf.
1368 If you want to use "perf lock", you also need to turn on
1369 CONFIG_EVENT_TRACING.
1370
1371 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1372 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1373
e7eebaf6
IM
1374config DEBUG_RT_MUTEXES
1375 bool "RT Mutex debugging, deadlock detection"
e7eebaf6
IM
1376 depends on DEBUG_KERNEL && RT_MUTEXES
1377 help
1378 This allows rt mutex semantics violations and rt mutex related
1379 deadlocks (lockups) to be detected and reported automatically.
1380
1da177e4 1381config DEBUG_SPINLOCK
4d9f34ad 1382 bool "Spinlock and rw-lock debugging: basic checks"
1da177e4 1383 depends on DEBUG_KERNEL
e335e3eb 1384 select UNINLINE_SPIN_UNLOCK
1da177e4
LT
1385 help
1386 Say Y here and build SMP to catch missing spinlock initialization
1387 and certain other kinds of spinlock errors commonly made. This is
1388 best used in conjunction with the NMI watchdog so that spinlock
1389 deadlocks are also debuggable.
1390
4d9f34ad
IM
1391config DEBUG_MUTEXES
1392 bool "Mutex debugging: basic checks"
bb630f9f 1393 depends on DEBUG_KERNEL && !PREEMPT_RT
4d9f34ad
IM
1394 help
1395 This feature allows mutex semantics violations to be detected and
1396 reported.
1397
23010027
DV
1398config DEBUG_WW_MUTEX_SLOWPATH
1399 bool "Wait/wound mutex debugging: Slowpath testing"
f07cbebb 1400 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
23010027
DV
1401 select DEBUG_LOCK_ALLOC
1402 select DEBUG_SPINLOCK
bb630f9f
TG
1403 select DEBUG_MUTEXES if !PREEMPT_RT
1404 select DEBUG_RT_MUTEXES if PREEMPT_RT
23010027
DV
1405 help
1406 This feature enables slowpath testing for w/w mutex users by
1407 injecting additional -EDEADLK wound/backoff cases. Together with
1408 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1409 will test all possible w/w mutex interface abuse with the
1410 exception of simply not acquiring all the required locks.
4d692373
RC
1411 Note that this feature can introduce significant overhead, so
1412 it really should not be enabled in a production or distro kernel,
1413 even a debug kernel. If you are a driver writer, enable it. If
1414 you are a distro, do not.
23010027 1415
5149cbac
WL
1416config DEBUG_RWSEMS
1417 bool "RW Semaphore debugging: basic checks"
c71fd893 1418 depends on DEBUG_KERNEL
5149cbac 1419 help
c71fd893
WL
1420 This debugging feature allows mismatched rw semaphore locks
1421 and unlocks to be detected and reported.
5149cbac 1422
4d9f34ad
IM
1423config DEBUG_LOCK_ALLOC
1424 bool "Lock debugging: detect incorrect freeing of live locks"
f07cbebb 1425 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1426 select DEBUG_SPINLOCK
bb630f9f 1427 select DEBUG_MUTEXES if !PREEMPT_RT
f5694788 1428 select DEBUG_RT_MUTEXES if RT_MUTEXES
4d9f34ad
IM
1429 select LOCKDEP
1430 help
1431 This feature will check whether any held lock (spinlock, rwlock,
1432 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1433 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1434 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1435 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1436 held during task exit.
1437
4d9f34ad
IM
1438config LOCKDEP
1439 bool
f07cbebb 1440 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1441 select STACKTRACE
4d9f34ad
IM
1442 select KALLSYMS
1443 select KALLSYMS_ALL
1444
395102db
DJ
1445config LOCKDEP_SMALL
1446 bool
1447
5dc33592
TH
1448config LOCKDEP_BITS
1449 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1450 depends on LOCKDEP && !LOCKDEP_SMALL
1451 range 10 30
1452 default 15
1453 help
1454 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1455
1456config LOCKDEP_CHAINS_BITS
1457 int "Bitsize for MAX_LOCKDEP_CHAINS"
1458 depends on LOCKDEP && !LOCKDEP_SMALL
1459 range 10 30
1460 default 16
1461 help
1462 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1463
1464config LOCKDEP_STACK_TRACE_BITS
1465 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1466 depends on LOCKDEP && !LOCKDEP_SMALL
1467 range 10 30
1468 default 19
1469 help
1470 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1471
1472config LOCKDEP_STACK_TRACE_HASH_BITS
1473 int "Bitsize for STACK_TRACE_HASH_SIZE"
1474 depends on LOCKDEP && !LOCKDEP_SMALL
1475 range 10 30
1476 default 14
1477 help
f478b998 1478 Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
5dc33592
TH
1479
1480config LOCKDEP_CIRCULAR_QUEUE_BITS
1481 int "Bitsize for elements in circular_queue struct"
1482 depends on LOCKDEP
1483 range 10 30
1484 default 12
1485 help
1486 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1487
4d9f34ad
IM
1488config DEBUG_LOCKDEP
1489 bool "Lock dependency engine debugging"
517e7aa5 1490 depends on DEBUG_KERNEL && LOCKDEP
997acaf6 1491 select DEBUG_IRQFLAGS
4d9f34ad
IM
1492 help
1493 If you say Y here, the lock dependency engine will do
1494 additional runtime checks to debug itself, at the price
1495 of more runtime overhead.
1496
d902db1e
FW
1497config DEBUG_ATOMIC_SLEEP
1498 bool "Sleep inside atomic section checking"
e8f7c70f 1499 select PREEMPT_COUNT
1da177e4 1500 depends on DEBUG_KERNEL
87a4c375 1501 depends on !ARCH_NO_PREEMPT
1da177e4
LT
1502 help
1503 If you say Y here, various routines which may sleep will become very
d902db1e
FW
1504 noisy if they are called inside atomic sections: when a spinlock is
1505 held, inside an rcu read side critical section, inside preempt disabled
1506 sections, inside an interrupt, etc...
1da177e4 1507
cae2ed9a
IM
1508config DEBUG_LOCKING_API_SELFTESTS
1509 bool "Locking API boot-time self-tests"
1510 depends on DEBUG_KERNEL
1511 help
1512 Say Y here if you want the kernel to run a short self-test during
1513 bootup. The self-test checks whether common types of locking bugs
1514 are detected by debugging mechanisms or not. (if you disable
9dbbc3b9 1515 lock debugging then those bugs won't be detected of course.)
cae2ed9a
IM
1516 The following locking APIs are covered: spinlocks, rwlocks,
1517 mutexes and rwsems.
1518
0af3fe1e
PM
1519config LOCK_TORTURE_TEST
1520 tristate "torture tests for locking"
1521 depends on DEBUG_KERNEL
1522 select TORTURE_TEST
0af3fe1e
PM
1523 help
1524 This option provides a kernel module that runs torture tests
1525 on kernel locking primitives. The kernel module may be built
1526 after the fact on the running kernel to be tested, if desired.
1527
1528 Say Y here if you want kernel locking-primitive torture tests
1529 to be built into the kernel.
1530 Say M if you want these torture tests to build as a module.
1531 Say N if you are unsure.
1532
f2a5fec1
CW
1533config WW_MUTEX_SELFTEST
1534 tristate "Wait/wound mutex selftests"
1535 help
1536 This option provides a kernel module that runs tests on the
1537 on the struct ww_mutex locking API.
1538
1539 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1540 with this test harness.
1541
1542 Say M if you want these self tests to build as a module.
1543 Say N if you are unsure.
1544
e9d338a0
PM
1545config SCF_TORTURE_TEST
1546 tristate "torture tests for smp_call_function*()"
1547 depends on DEBUG_KERNEL
1548 select TORTURE_TEST
1549 help
1550 This option provides a kernel module that runs torture tests
1551 on the smp_call_function() family of primitives. The kernel
1552 module may be built after the fact on the running kernel to
1553 be tested, if desired.
1554
35feb604
PM
1555config CSD_LOCK_WAIT_DEBUG
1556 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1557 depends on DEBUG_KERNEL
1558 depends on 64BIT
1559 default n
1560 help
1561 This option enables debug prints when CPUs are slow to respond
1562 to the smp_call_function*() IPI wrappers. These debug prints
1563 include the IPI handler function currently executing (if any)
1564 and relevant stack traces.
1565
c5219860
PM
1566config CSD_LOCK_WAIT_DEBUG_DEFAULT
1567 bool "Default csd_lock_wait() debugging on at boot time"
1568 depends on CSD_LOCK_WAIT_DEBUG
1569 depends on 64BIT
1570 default n
1571 help
1572 This option causes the csdlock_debug= kernel boot parameter to
1573 default to 1 (basic debugging) instead of 0 (no debugging).
1574
9eade16b 1575endmenu # lock debugging
8637c099 1576
9eade16b 1577config TRACE_IRQFLAGS
ed004953 1578 depends on TRACE_IRQFLAGS_SUPPORT
9eade16b 1579 bool
5ca43f6c 1580 help
9eade16b
DH
1581 Enables hooks to interrupt enabling and disabling for
1582 either tracing or lock debugging.
5ca43f6c 1583
ed004953 1584config TRACE_IRQFLAGS_NMI
1585 def_bool y
1586 depends on TRACE_IRQFLAGS
1587 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1588
1a3ea611
PM
1589config NMI_CHECK_CPU
1590 bool "Debugging for CPUs failing to respond to backtrace requests"
1591 depends on DEBUG_KERNEL
1592 depends on X86
1593 default n
1594 help
1595 Enables debug prints when a CPU fails to respond to a given
1596 backtrace NMI. These prints provide some reasons why a CPU
1597 might legitimately be failing to respond, for example, if it
1598 is offline of if ignore_nmis is set.
1599
997acaf6
MR
1600config DEBUG_IRQFLAGS
1601 bool "Debug IRQ flag manipulation"
1602 help
1603 Enables checks for potentially unsafe enabling or disabling of
1604 interrupts, such as calling raw_local_irq_restore() when interrupts
1605 are enabled.
1606
8637c099 1607config STACKTRACE
0c38e1fe 1608 bool "Stack backtrace support"
8637c099 1609 depends on STACKTRACE_SUPPORT
0c38e1fe
DJ
1610 help
1611 This option causes the kernel to create a /proc/pid/stack for
1612 every process, showing its current stack trace.
1613 It is also used by various kernel debugging features that require
1614 stack trace generation.
5ca43f6c 1615
eecabf56
TT
1616config WARN_ALL_UNSEEDED_RANDOM
1617 bool "Warn for all uses of unseeded randomness"
1618 default n
d06bfd19
JD
1619 help
1620 Some parts of the kernel contain bugs relating to their use of
1621 cryptographically secure random numbers before it's actually possible
1622 to generate those numbers securely. This setting ensures that these
1623 flaws don't go unnoticed, by enabling a message, should this ever
1624 occur. This will allow people with obscure setups to know when things
1625 are going wrong, so that they might contact developers about fixing
1626 it.
1627
eecabf56
TT
1628 Unfortunately, on some models of some architectures getting
1629 a fully seeded CRNG is extremely difficult, and so this can
1630 result in dmesg getting spammed for a surprisingly long
1631 time. This is really bad from a security perspective, and
1632 so architecture maintainers really need to do what they can
1633 to get the CRNG seeded sooner after the system is booted.
4c5d114e 1634 However, since users cannot do anything actionable to
cc1e127b 1635 address this, by default this option is disabled.
eecabf56
TT
1636
1637 Say Y here if you want to receive warnings for all uses of
1638 unseeded randomness. This will be of use primarily for
4c5d114e 1639 those developers interested in improving the security of
eecabf56
TT
1640 Linux kernels running on their architecture (or
1641 subarchitecture).
d06bfd19 1642
1da177e4
LT
1643config DEBUG_KOBJECT
1644 bool "kobject debugging"
1645 depends on DEBUG_KERNEL
1646 help
1647 If you say Y here, some extra kobject debugging messages will be sent
aca52c39 1648 to the syslog.
1da177e4 1649
c817a67e
RK
1650config DEBUG_KOBJECT_RELEASE
1651 bool "kobject release debugging"
2a999aa0 1652 depends on DEBUG_OBJECTS_TIMERS
c817a67e
RK
1653 help
1654 kobjects are reference counted objects. This means that their
1655 last reference count put is not predictable, and the kobject can
b6c69474 1656 live on past the point at which a driver decides to drop its
c817a67e
RK
1657 initial reference to the kobject gained on allocation. An
1658 example of this would be a struct device which has just been
1659 unregistered.
1660
1661 However, some buggy drivers assume that after such an operation,
1662 the memory backing the kobject can be immediately freed. This
1663 goes completely against the principles of a refcounted object.
1664
1665 If you say Y here, the kernel will delay the release of kobjects
1666 on the last reference count to improve the visibility of this
1667 kind of kobject release bug.
1668
9b2a60c4
CM
1669config HAVE_DEBUG_BUGVERBOSE
1670 bool
1671
3be5cbcd 1672menu "Debug kernel data structures"
1da177e4 1673
199a9afc
DJ
1674config DEBUG_LIST
1675 bool "Debug linked list manipulation"
4520bcb2 1676 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
199a9afc
DJ
1677 help
1678 Enable this to turn on extended checks in the linked-list
1679 walking routines.
1680
1681 If unsure, say N.
1682
8e18faea 1683config DEBUG_PLIST
b8cfff68
DS
1684 bool "Debug priority linked list manipulation"
1685 depends on DEBUG_KERNEL
1686 help
1687 Enable this to turn on extended checks in the priority-ordered
1688 linked-list (plist) walking routines. This checks the entire
1689 list multiple times during each manipulation.
1690
1691 If unsure, say N.
1692
d6ec0842
JA
1693config DEBUG_SG
1694 bool "Debug SG table operations"
1695 depends on DEBUG_KERNEL
1696 help
1697 Enable this to turn on checks on scatter-gather tables. This can
1698 help find problems with drivers that do not properly initialize
1699 their sg tables.
1700
1701 If unsure, say N.
1702
1b2439db
AV
1703config DEBUG_NOTIFIERS
1704 bool "Debug notifier call chains"
1705 depends on DEBUG_KERNEL
1706 help
1707 Enable this to turn on sanity checking for notifier call chains.
1708 This is most useful for kernel developers to make sure that
1709 modules properly unregister themselves from notifier chains.
1710 This is a relatively cheap check but if you care about maximum
1711 performance, say N.
1712
3be5cbcd
CD
1713config BUG_ON_DATA_CORRUPTION
1714 bool "Trigger a BUG when data corruption is detected"
1715 select DEBUG_LIST
1716 help
1717 Select this option if the kernel should BUG when it encounters
1718 data corruption in kernel memory structures when they get checked
1719 for validity.
1720
1721 If unsure, say N.
1722
54a611b6
LH
1723config DEBUG_MAPLE_TREE
1724 bool "Debug maple trees"
1725 depends on DEBUG_KERNEL
1726 help
1727 Enable maple tree debugging information and extra validations.
1728
1729 If unsure, say N.
1730
3be5cbcd
CD
1731endmenu
1732
e0e81739
DH
1733config DEBUG_CREDENTIALS
1734 bool "Debug credential management"
1735 depends on DEBUG_KERNEL
1736 help
1737 Enable this to turn on some debug checking for credential
1738 management. The additional code keeps track of the number of
1739 pointers from task_structs to any given cred struct, and checks to
1740 see that this number never exceeds the usage count of the cred
1741 struct.
1742
1743 Furthermore, if SELinux is enabled, this also checks that the
1744 security pointer in the cred struct is never seen to be invalid.
1745
1746 If unsure, say N.
1747
43a0a2a7 1748source "kernel/rcu/Kconfig.debug"
2f03e3ca 1749
f303fccb
TH
1750config DEBUG_WQ_FORCE_RR_CPU
1751 bool "Force round-robin CPU selection for unbound work items"
1752 depends on DEBUG_KERNEL
1753 default n
1754 help
1755 Workqueue used to implicitly guarantee that work items queued
1756 without explicit CPU specified are put on the local CPU. This
1757 guarantee is no longer true and while local CPU is still
1758 preferred work items may be put on foreign CPUs. Kernel
1759 parameter "workqueue.debug_force_rr_cpu" is added to force
1760 round-robin CPU selection to flush out usages which depend on the
1761 now broken guarantee. This config option enables the debug
1762 feature by default. When enabled, memory and cache locality will
1763 be impacted.
1764
757c989b
TG
1765config CPU_HOTPLUG_STATE_CONTROL
1766 bool "Enable CPU hotplug state control"
1767 depends on DEBUG_KERNEL
1768 depends on HOTPLUG_CPU
1769 default n
1770 help
1771 Allows to write steps between "offline" and "online" to the CPUs
1772 sysfs target file so states can be stepped granular. This is a debug
1773 option for now as the hotplug machinery cannot be stopped and
1774 restarted at arbitrary points yet.
1775
1776 Say N if your are unsure.
1777
09a74952
CD
1778config LATENCYTOP
1779 bool "Latency measuring infrastructure"
1780 depends on DEBUG_KERNEL
1781 depends on STACKTRACE_SUPPORT
1782 depends on PROC_FS
7d37cb2c 1783 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
09a74952
CD
1784 select KALLSYMS
1785 select KALLSYMS_ALL
1786 select STACKTRACE
1787 select SCHEDSTATS
09a74952
CD
1788 help
1789 Enable this option if you want to use the LatencyTOP tool
1790 to find out which userspace is blocking on what kernel operations.
1791
6ab42860
TH
1792config DEBUG_CGROUP_REF
1793 bool "Disable inlining of cgroup css reference count functions"
1794 depends on DEBUG_KERNEL
1795 depends on CGROUPS
1796 depends on KPROBES
1797 default n
1798 help
1799 Force cgroup css reference count functions to not be inlined so
1800 that they can be kprobed for debugging.
1801
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1802source "kernel/trace/Kconfig"
1803
1804config PROVIDE_OHCI1394_DMA_INIT
1805 bool "Remote debugging over FireWire early on boot"
1806 depends on PCI && X86
1807 help
1808 If you want to debug problems which hang or crash the kernel early
1809 on boot and the crashing machine has a FireWire port, you can use
1810 this feature to remotely access the memory of the crashed machine
1811 over FireWire. This employs remote DMA as part of the OHCI1394
1812 specification which is now the standard for FireWire controllers.
1813
1814 With remote DMA, you can monitor the printk buffer remotely using
1815 firescope and access all memory below 4GB using fireproxy from gdb.
1816 Even controlling a kernel debugger is possible using remote DMA.
1817
1818 Usage:
1819
1820 If ohci1394_dma=early is used as boot parameter, it will initialize
1821 all OHCI1394 controllers which are found in the PCI config space.
1822
1823 As all changes to the FireWire bus such as enabling and disabling
1824 devices cause a bus reset and thereby disable remote DMA for all
1825 devices, be sure to have the cable plugged and FireWire enabled on
1826 the debugging host before booting the debug target for debugging.
1827
1828 This code (~1k) is freed after boot. By then, the firewire stack
1829 in charge of the OHCI-1394 controllers should be used instead.
1830
a74e2a22 1831 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
09a74952 1832
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1833source "samples/Kconfig"
1834
1835config ARCH_HAS_DEVMEM_IS_ALLOWED
1836 bool
1837
1838config STRICT_DEVMEM
1839 bool "Filter access to /dev/mem"
1840 depends on MMU && DEVMEM
527701ed 1841 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
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1842 default y if PPC || X86 || ARM64
1843 help
1844 If this option is disabled, you allow userspace (root) access to all
1845 of memory, including kernel and userspace memory. Accidental
1846 access to this is obviously disastrous, but specific access can
1847 be used by people debugging the kernel. Note that with PAT support
1848 enabled, even in this case there are restrictions on /dev/mem
1849 use due to the cache aliasing requirements.
1850
1851 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1852 file only allows userspace access to PCI space and the BIOS code and
1853 data regions. This is sufficient for dosemu and X and all common
1854 users of /dev/mem.
1855
1856 If in doubt, say Y.
1857
1858config IO_STRICT_DEVMEM
1859 bool "Filter I/O access to /dev/mem"
1860 depends on STRICT_DEVMEM
1861 help
1862 If this option is disabled, you allow userspace (root) access to all
1863 io-memory regardless of whether a driver is actively using that
1864 range. Accidental access to this is obviously disastrous, but
1865 specific access can be used by people debugging kernel drivers.
1866
1867 If this option is switched on, the /dev/mem file only allows
1868 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1869 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1870 if the driver using a given range cannot be disabled.
1871
1872 If in doubt, say Y.
1873
1874menu "$(SRCARCH) Debugging"
1875
1876source "arch/$(SRCARCH)/Kconfig.debug"
1877
1878endmenu
1879
1880menu "Kernel Testing and Coverage"
1881
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1882source "lib/kunit/Kconfig"
1883
8d438288
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1884config NOTIFIER_ERROR_INJECTION
1885 tristate "Notifier error injection"
1886 depends on DEBUG_KERNEL
1887 select DEBUG_FS
1888 help
e41e85cc 1889 This option provides the ability to inject artificial errors to
8d438288
AM
1890 specified notifier chain callbacks. It is useful to test the error
1891 handling of notifier call chain failures.
1892
1893 Say N if unsure.
1894
048b9c35
AM
1895config PM_NOTIFIER_ERROR_INJECT
1896 tristate "PM notifier error injection module"
1897 depends on PM && NOTIFIER_ERROR_INJECTION
1898 default m if PM_DEBUG
1899 help
e41e85cc 1900 This option provides the ability to inject artificial errors to
048b9c35
AM
1901 PM notifier chain callbacks. It is controlled through debugfs
1902 interface /sys/kernel/debug/notifier-error-inject/pm
1903
1904 If the notifier call chain should be failed with some events
1905 notified, write the error code to "actions/<notifier event>/error".
1906
1907 Example: Inject PM suspend error (-12 = -ENOMEM)
1908
1909 # cd /sys/kernel/debug/notifier-error-inject/pm/
1910 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1911 # echo mem > /sys/power/state
1912 bash: echo: write error: Cannot allocate memory
1913
1914 To compile this code as a module, choose M here: the module will
1915 be called pm-notifier-error-inject.
1916
1917 If unsure, say N.
1918
d526e85f
BH
1919config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1920 tristate "OF reconfig notifier error injection module"
1921 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dd 1922 help
e41e85cc 1923 This option provides the ability to inject artificial errors to
d526e85f 1924 OF reconfig notifier chain callbacks. It is controlled
08dfb4dd 1925 through debugfs interface under
d526e85f 1926 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
08dfb4dd
AM
1927
1928 If the notifier call chain should be failed with some events
1929 notified, write the error code to "actions/<notifier event>/error".
1930
1931 To compile this code as a module, choose M here: the module will
e12a95f4 1932 be called of-reconfig-notifier-error-inject.
08dfb4dd
AM
1933
1934 If unsure, say N.
1935
02fff96a
NA
1936config NETDEV_NOTIFIER_ERROR_INJECT
1937 tristate "Netdev notifier error injection module"
1938 depends on NET && NOTIFIER_ERROR_INJECTION
1939 help
1940 This option provides the ability to inject artificial errors to
1941 netdevice notifier chain callbacks. It is controlled through debugfs
1942 interface /sys/kernel/debug/notifier-error-inject/netdev
1943
1944 If the notifier call chain should be failed with some events
1945 notified, write the error code to "actions/<notifier event>/error".
1946
1947 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1948
1949 # cd /sys/kernel/debug/notifier-error-inject/netdev
1950 # echo -22 > actions/NETDEV_CHANGEMTU/error
1951 # ip link set eth0 mtu 1024
1952 RTNETLINK answers: Invalid argument
1953
1954 To compile this code as a module, choose M here: the module will
1955 be called netdev-notifier-error-inject.
1956
1957 If unsure, say N.
1958
f1b4bd06 1959config FUNCTION_ERROR_INJECTION
a4412fdd 1960 bool "Fault-injections of functions"
f1b4bd06 1961 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
a4412fdd
SRG
1962 help
1963 Add fault injections into various functions that are annotated with
1964 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
ca0f2cfc 1965 value of these functions. This is useful to test error paths of code.
a4412fdd
SRG
1966
1967 If unsure, say N
f1b4bd06 1968
6ff1cb35 1969config FAULT_INJECTION
1ab8509a
AM
1970 bool "Fault-injection framework"
1971 depends on DEBUG_KERNEL
329409ae
AM
1972 help
1973 Provide fault-injection framework.
1974 For more details, see Documentation/fault-injection/.
6ff1cb35 1975
8a8b6502 1976config FAILSLAB
1ab8509a
AM
1977 bool "Fault-injection capability for kmalloc"
1978 depends on FAULT_INJECTION
773ff60e 1979 depends on SLAB || SLUB
8a8b6502 1980 help
1ab8509a 1981 Provide fault-injection capability for kmalloc.
8a8b6502 1982
933e312e 1983config FAIL_PAGE_ALLOC
29b46fa3 1984 bool "Fault-injection capability for alloc_pages()"
1ab8509a 1985 depends on FAULT_INJECTION
933e312e 1986 help
1ab8509a 1987 Provide fault-injection capability for alloc_pages().
933e312e 1988
2c739ced
AL
1989config FAULT_INJECTION_USERCOPY
1990 bool "Fault injection capability for usercopy functions"
1991 depends on FAULT_INJECTION
1992 help
1993 Provides fault-injection capability to inject failures
1994 in usercopy functions (copy_from_user(), get_user(), ...).
1995
c17bb495 1996config FAIL_MAKE_REQUEST
86327d19 1997 bool "Fault-injection capability for disk IO"
581d4e28 1998 depends on FAULT_INJECTION && BLOCK
c17bb495 1999 help
1ab8509a 2000 Provide fault-injection capability for disk IO.
c17bb495 2001
581d4e28 2002config FAIL_IO_TIMEOUT
f4d01439 2003 bool "Fault-injection capability for faking disk interrupts"
581d4e28
JA
2004 depends on FAULT_INJECTION && BLOCK
2005 help
2006 Provide fault-injection capability on end IO handling. This
2007 will make the block layer "forget" an interrupt as configured,
2008 thus exercising the error handling.
2009
2010 Only works with drivers that use the generic timeout handling,
9dbbc3b9 2011 for others it won't do anything.
581d4e28 2012
ab51fbab
DB
2013config FAIL_FUTEX
2014 bool "Fault-injection capability for futexes"
2015 select DEBUG_FS
2016 depends on FAULT_INJECTION && FUTEX
2017 help
2018 Provide fault-injection capability for futexes.
2019
f1b4bd06
MP
2020config FAULT_INJECTION_DEBUG_FS
2021 bool "Debugfs entries for fault-injection capabilities"
2022 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2023 help
2024 Enable configuration of fault-injection capabilities via debugfs.
2025
4b1a29a7
MH
2026config FAIL_FUNCTION
2027 bool "Fault-injection capability for functions"
2028 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2029 help
2030 Provide function-based fault-injection capability.
2031 This will allow you to override a specific function with a return
2032 with given return value. As a result, function caller will see
2033 an error value and have to handle it. This is useful to test the
2034 error handling in various subsystems.
2035
f1b4bd06
MP
2036config FAIL_MMC_REQUEST
2037 bool "Fault-injection capability for MMC IO"
2038 depends on FAULT_INJECTION_DEBUG_FS && MMC
6ff1cb35 2039 help
f1b4bd06
MP
2040 Provide fault-injection capability for MMC IO.
2041 This will make the mmc core return data errors. This is
2042 useful to test the error handling in the mmc block device
2043 and to test how the mmc host driver handles retries from
2044 the block device.
1df49008 2045
c782af25
CL
2046config FAIL_SUNRPC
2047 bool "Fault-injection capability for SunRPC"
2048 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2049 help
2050 Provide fault-injection capability for SunRPC and
2051 its consumers.
2052
4668c7a2
AM
2053config FAULT_INJECTION_CONFIGFS
2054 bool "Configfs interface for fault-injection capabilities"
d325c162
AM
2055 depends on FAULT_INJECTION
2056 select CONFIGFS_FS
4668c7a2
AM
2057 help
2058 This option allows configfs-based drivers to dynamically configure
2059 fault-injection via configfs. Each parameter for driver-specific
2060 fault-injection can be made visible as a configfs attribute in a
2061 configfs group.
2062
2063
1df49008
AM
2064config FAULT_INJECTION_STACKTRACE_FILTER
2065 bool "stacktrace filter for fault-injection capabilities"
4668c7a2
AM
2066 depends on FAULT_INJECTION
2067 depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
1df49008 2068 select STACKTRACE
7d37cb2c 2069 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1df49008
AM
2070 help
2071 Provide stacktrace filter for fault-injection capabilities
267c4025 2072
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2073config ARCH_HAS_KCOV
2074 bool
cc3fa840 2075 help
09a74952
CD
2076 An architecture should select this when it can successfully
2077 build and run with CONFIG_KCOV. This typically requires
2078 disabling instrumentation for some early boot code.
cc3fa840 2079
09a74952
CD
2080config CC_HAS_SANCOV_TRACE_PC
2081 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
cc3fa840 2082
cc3fa840 2083
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2084config KCOV
2085 bool "Code coverage for fuzzing"
2086 depends on ARCH_HAS_KCOV
2087 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
22102f45 2088 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
bece04b5 2089 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
09a74952
CD
2090 select DEBUG_FS
2091 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
22102f45 2092 select OBJTOOL if HAVE_NOINSTR_HACK
09a74952
CD
2093 help
2094 KCOV exposes kernel code coverage information in a form suitable
2095 for coverage-guided fuzzing (randomized testing).
cc3fa840 2096
09a74952
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2097 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2098 different machines and across reboots. If you need stable PC values,
2099 disable RANDOMIZE_BASE.
cc3fa840 2100
09a74952 2101 For more details, see Documentation/dev-tools/kcov.rst.
cc3fa840 2102
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2103config KCOV_ENABLE_COMPARISONS
2104 bool "Enable comparison operands collection by KCOV"
2105 depends on KCOV
2106 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2107 help
2108 KCOV also exposes operands of every comparison in the instrumented
2109 code along with operand sizes and PCs of the comparison instructions.
2110 These operands can be used by fuzzing engines to improve the quality
2111 of fuzzing coverage.
cc3fa840 2112
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2113config KCOV_INSTRUMENT_ALL
2114 bool "Instrument all code by default"
2115 depends on KCOV
2116 default y
2117 help
2118 If you are doing generic system call fuzzing (like e.g. syzkaller),
2119 then you will want to instrument the whole kernel and you should
2120 say y here. If you are doing more targeted fuzzing (like e.g.
2121 filesystem fuzzing with AFL) then you will want to enable coverage
2122 for more specific subsets of files, and should say n here.
84bc809e 2123
5ff3b30a
AK
2124config KCOV_IRQ_AREA_SIZE
2125 hex "Size of interrupt coverage collection area in words"
2126 depends on KCOV
2127 default 0x40000
2128 help
2129 KCOV uses preallocated per-cpu areas to collect coverage from
2130 soft interrupts. This specifies the size of those areas in the
2131 number of unsigned long words.
2132
d3deafaa
VL
2133menuconfig RUNTIME_TESTING_MENU
2134 bool "Runtime Testing"
908009e8 2135 def_bool y
d3deafaa
VL
2136
2137if RUNTIME_TESTING_MENU
881c5149 2138
d5528cc1
GU
2139config TEST_DHRY
2140 tristate "Dhrystone benchmark test"
2141 help
2142 Enable this to include the Dhrystone 2.1 benchmark. This test
2143 calculates the number of Dhrystones per second, and the number of
2144 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2145 by 1757 (the number of Dhrystones per second obtained on the VAX
2146 11/780, nominally a 1 MIPS machine).
2147
2148 To run the benchmark, it needs to be enabled explicitly, either from
2149 the kernel command line (when built-in), or from userspace (when
2150 built-in or modular.
2151
2152 Run once during kernel boot:
2153
2154 test_dhry.run
2155
2156 Set number of iterations from kernel command line:
2157
2158 test_dhry.iterations=<n>
2159
2160 Set number of iterations from userspace:
2161
2162 echo <n> > /sys/module/test_dhry/parameters/iterations
2163
2164 Trigger manual run from userspace:
2165
2166 echo y > /sys/module/test_dhry/parameters/run
2167
2168 If the number of iterations is <= 0, the test will devise a suitable
2169 number of iterations (test runs for at least 2s) automatically.
2170 This process takes ca. 4s.
2171
2172 If unsure, say N.
2173
881c5149
DH
2174config LKDTM
2175 tristate "Linux Kernel Dump Test Tool Module"
2176 depends on DEBUG_FS
881c5149
DH
2177 help
2178 This module enables testing of the different dumping mechanisms by
2179 inducing system failures at predefined crash points.
2180 If you don't need it: say N
2181 Choose M here to compile this code as a module. The module will be
2182 called lkdtm.
2183
2184 Documentation on how to use the module can be found in
10ffebbe 2185 Documentation/fault-injection/provoke-crashes.rst
881c5149 2186
d3c0ca49
SV
2187config CPUMASK_KUNIT_TEST
2188 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
c41e8866
SV
2189 depends on KUNIT
2190 default KUNIT_ALL_TESTS
2191 help
2192 Enable to turn on cpumask tests, running at boot or module load time.
2193
d3c0ca49
SV
2194 For more information on KUnit and unit tests in general, please refer
2195 to the KUnit documentation in Documentation/dev-tools/kunit/.
2196
c41e8866
SV
2197 If unsure, say N.
2198
881c5149 2199config TEST_LIST_SORT
ebd09577
DL
2200 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2201 depends on KUNIT
2202 default KUNIT_ALL_TESTS
881c5149
DH
2203 help
2204 Enable this to turn on 'list_sort()' function test. This test is
e327fd7c
GU
2205 executed only once during system boot (so affects only boot time),
2206 or at module load time.
881c5149
DH
2207
2208 If unsure, say N.
2209
6e24628d
IR
2210config TEST_MIN_HEAP
2211 tristate "Min heap test"
2212 depends on DEBUG_KERNEL || m
2213 help
2214 Enable this to turn on min heap function tests. This test is
2215 executed only once during system boot (so affects only boot time),
2216 or at module load time.
2217
2218 If unsure, say N.
2219
c5adae95 2220config TEST_SORT
36f33b56
DL
2221 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2222 depends on KUNIT
2223 default KUNIT_ALL_TESTS
c5adae95 2224 help
5c4e6798
GU
2225 This option enables the self-test function of 'sort()' at boot,
2226 or at module load time.
c5adae95
KF
2227
2228 If unsure, say N.
2229
5086ea4b
MR
2230config TEST_DIV64
2231 tristate "64bit/32bit division and modulo test"
2232 depends on DEBUG_KERNEL || m
2233 help
2234 Enable this to turn on 'do_div()' function test. This test is
2235 executed only once during system boot (so affects only boot time),
2236 or at module load time.
2237
2238 If unsure, say N.
2239
881c5149 2240config KPROBES_SANITY_TEST
dcbb2ee2 2241 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
881c5149
DH
2242 depends on DEBUG_KERNEL
2243 depends on KPROBES
e44e81c5 2244 depends on KUNIT
de3db3f8 2245 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
dcbb2ee2 2246 default KUNIT_ALL_TESTS
881c5149
DH
2247 help
2248 This option provides for testing basic kprobes functionality on
5a6cf77f 2249 boot. Samples of kprobe and kretprobe are inserted and
881c5149
DH
2250 verified for functionality.
2251
2252 Say N if you are unsure.
2253
f4616fab
MH
2254config FPROBE_SANITY_TEST
2255 bool "Self test for fprobe"
2256 depends on DEBUG_KERNEL
2257 depends on FPROBE
2258 depends on KUNIT=y
2259 help
2260 This option will enable testing the fprobe when the system boot.
2261 A series of tests are made to verify that the fprobe is functioning
2262 properly.
2263
2264 Say N if you are unsure.
2265
881c5149
DH
2266config BACKTRACE_SELF_TEST
2267 tristate "Self test for the backtrace code"
2268 depends on DEBUG_KERNEL
881c5149
DH
2269 help
2270 This option provides a kernel module that can be used to test
2271 the kernel stack backtrace code. This option is not useful
2272 for distributions or general kernels, but only for kernel
2273 developers working on architecture code.
2274
2275 Note that if you want to also test saved backtraces, you will
2276 have to enable STACKTRACE as well.
2277
2278 Say N if you are unsure.
2279
914a7b50
ED
2280config TEST_REF_TRACKER
2281 tristate "Self test for reference tracker"
2282 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2283 select REF_TRACKER
2284 help
2285 This option provides a kernel module performing tests
2286 using reference tracker infrastructure.
2287
2288 Say N if you are unsure.
2289
910a742d
ML
2290config RBTREE_TEST
2291 tristate "Red-Black tree test"
7c993e11 2292 depends on DEBUG_KERNEL
910a742d
ML
2293 help
2294 A benchmark measuring the performance of the rbtree library.
2295 Also includes rbtree invariant checks.
2296
4b4f3acc
FB
2297config REED_SOLOMON_TEST
2298 tristate "Reed-Solomon library test"
2299 depends on DEBUG_KERNEL || m
2300 select REED_SOLOMON
2301 select REED_SOLOMON_ENC16
2302 select REED_SOLOMON_DEC16
2303 help
2304 This option enables the self-test function of rslib at boot,
2305 or at module load time.
2306
2307 If unsure, say N.
2308
fff3fd8a
ML
2309config INTERVAL_TREE_TEST
2310 tristate "Interval tree test"
0f789b67 2311 depends on DEBUG_KERNEL
a88cc108 2312 select INTERVAL_TREE
fff3fd8a
ML
2313 help
2314 A benchmark measuring the performance of the interval tree library
2315
623fd807
GT
2316config PERCPU_TEST
2317 tristate "Per cpu operations test"
2318 depends on m && DEBUG_KERNEL
2319 help
2320 Enable this option to build test module which validates per-cpu
2321 operations.
2322
2323 If unsure, say N.
2324
881c5149 2325config ATOMIC64_SELFTEST
55ded955 2326 tristate "Perform an atomic64_t self-test"
881c5149 2327 help
55ded955
GU
2328 Enable this option to test the atomic64_t functions at boot or
2329 at module load time.
881c5149
DH
2330
2331 If unsure, say N.
2332
2333config ASYNC_RAID6_TEST
2334 tristate "Self test for hardware accelerated raid6 recovery"
2335 depends on ASYNC_RAID6_RECOV
2336 select ASYNC_MEMCPY
a7f7f624 2337 help
881c5149
DH
2338 This is a one-shot self test that permutes through the
2339 recovery of all the possible two disk failure scenarios for a
2340 N-disk array. Recovery is performed with the asynchronous
2341 raid6 recovery routines, and will optionally use an offload
2342 engine if one is available.
2343
2344 If unsure, say N.
2345
64d1d77a
AS
2346config TEST_HEXDUMP
2347 tristate "Test functions located in the hexdump module at runtime"
2348
b2ff70a0
MC
2349config STRING_SELFTEST
2350 tristate "Test string functions at runtime"
2351
881c5149
DH
2352config TEST_STRING_HELPERS
2353 tristate "Test functions located in the string_helpers module at runtime"
2354
2355config TEST_KSTRTOX
2356 tristate "Test kstrto*() family of functions at runtime"
2357
707cc728
RV
2358config TEST_PRINTF
2359 tristate "Test printf() family of functions at runtime"
2360
50f530e1
RF
2361config TEST_SCANF
2362 tristate "Test scanf() family of functions at runtime"
2363
5fd003f5
DD
2364config TEST_BITMAP
2365 tristate "Test bitmap_*() family of functions at runtime"
5fd003f5
DD
2366 help
2367 Enable this option to test the bitmap functions at boot.
2368
2369 If unsure, say N.
2370
cfaff0e5
AS
2371config TEST_UUID
2372 tristate "Test functions located in the uuid module at runtime"
2373
ad3d6c72
MW
2374config TEST_XARRAY
2375 tristate "Test the XArray code at runtime"
2376
120b1162 2377config TEST_MAPLE_TREE
a5199577
LH
2378 tristate "Test the Maple Tree code at runtime or module load"
2379 help
2380 Enable this option to test the maple tree code functions at boot, or
2381 when the module is loaded. Enable "Debug Maple Trees" will enable
2382 more verbose output on failures.
2383
2384 If unsure, say N.
120b1162 2385
7e1e7763 2386config TEST_RHASHTABLE
9d6dbe1b 2387 tristate "Perform selftest on resizable hash table"
7e1e7763
TG
2388 help
2389 Enable this option to test the rhashtable functions at boot.
2390
2391 If unsure, say N.
2392
8ab8ba38
MW
2393config TEST_IDA
2394 tristate "Perform selftest on IDA functions"
2395
44091d29
JP
2396config TEST_PARMAN
2397 tristate "Perform selftest on priority array manager"
44091d29
JP
2398 depends on PARMAN
2399 help
2400 Enable this option to test priority array manager on boot
2401 (or module load).
2402
2403 If unsure, say N.
2404
6aed82de
DL
2405config TEST_IRQ_TIMINGS
2406 bool "IRQ timings selftest"
2407 depends on IRQ_TIMINGS
2408 help
2409 Enable this option to test the irq timings code on boot.
2410
2411 If unsure, say N.
2412
8a6f0b47 2413config TEST_LKM
93e9ef83 2414 tristate "Test module loading with 'hello world' module"
93e9ef83
KC
2415 depends on m
2416 help
2417 This builds the "test_module" module that emits "Hello, world"
2418 on printk when loaded. It is designed to be used for basic
2419 evaluation of the module loading subsystem (for example when
2420 validating module verification). It lacks any extra dependencies,
2421 and will not normally be loaded by the system unless explicitly
2422 requested by name.
2423
2424 If unsure, say N.
2425
c348c163 2426config TEST_BITOPS
6af132f3 2427 tristate "Test module for compilation of bitops operations"
c348c163
JB
2428 depends on m
2429 help
2430 This builds the "test_bitops" module that is much like the
2431 TEST_LKM module except that it does a basic exercise of the
6af132f3
WY
2432 set/clear_bit macros and get_count_order/long to make sure there are
2433 no compiler warnings from C=1 sparse checker or -Wextra
2434 compilations. It has no dependencies and doesn't run or load unless
2435 explicitly requested by name. for example: modprobe test_bitops.
c348c163
JB
2436
2437 If unsure, say N.
2438
3f21a6b7
URS
2439config TEST_VMALLOC
2440 tristate "Test module for stress/performance analysis of vmalloc allocator"
2441 default n
2442 depends on MMU
2443 depends on m
2444 help
2445 This builds the "test_vmalloc" module that should be used for
2446 stress and performance analysis. So, any new change for vmalloc
2447 subsystem can be evaluated from performance and stability point
2448 of view.
2449
2450 If unsure, say N.
2451
3e2a4c18
KC
2452config TEST_USER_COPY
2453 tristate "Test user/kernel boundary protections"
3e2a4c18
KC
2454 depends on m
2455 help
2456 This builds the "test_user_copy" module that runs sanity checks
2457 on the copy_to/from_user infrastructure, making sure basic
2458 user/kernel boundary testing is working. If it fails to load,
2459 a regression has been detected in the user/kernel memory boundary
2460 protections.
2461
2462 If unsure, say N.
2463
64a8946b
AS
2464config TEST_BPF
2465 tristate "Test BPF filter functionality"
98920ba6 2466 depends on m && NET
64a8946b
AS
2467 help
2468 This builds the "test_bpf" module that runs various test vectors
2469 against the BPF interpreter or BPF JIT compiler depending on the
2470 current setting. This is in particular useful for BPF JIT compiler
2471 development, but also to run regression tests against changes in
3c731eba
AS
2472 the interpreter code. It also enables test stubs for eBPF maps and
2473 verifier used by user space verifier testsuite.
64a8946b
AS
2474
2475 If unsure, say N.
2476
509e56b3
MB
2477config TEST_BLACKHOLE_DEV
2478 tristate "Test blackhole netdev functionality"
2479 depends on m && NET
2480 help
2481 This builds the "test_blackhole_dev" module that validates the
2482 data path through this blackhole netdev.
2483
2484 If unsure, say N.
2485
dceeb3e7 2486config FIND_BIT_BENCHMARK
4441fca0 2487 tristate "Test find_bit functions"
4441fca0
YN
2488 help
2489 This builds the "test_find_bit" module that measure find_*_bit()
2490 functions performance.
2491
2492 If unsure, say N.
2493
0a8adf58
KC
2494config TEST_FIRMWARE
2495 tristate "Test firmware loading via userspace interface"
0a8adf58
KC
2496 depends on FW_LOADER
2497 help
2498 This builds the "test_firmware" module that creates a userspace
2499 interface for testing firmware loading. This can be used to
2500 control the triggering of firmware loading without needing an
2501 actual firmware-using device. The contents can be rechecked by
2502 userspace.
2503
2504 If unsure, say N.
2505
9308f2f9
LR
2506config TEST_SYSCTL
2507 tristate "sysctl test driver"
9308f2f9
LR
2508 depends on PROC_SYSCTL
2509 help
2510 This builds the "test_sysctl" module. This driver enables to test the
2511 proc sysctl interfaces available to drivers safely without affecting
2512 production knobs which might alter system functionality.
2513
2514 If unsure, say N.
2515
d2585f51 2516config BITFIELD_KUNIT
dcbb2ee2 2517 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
d2585f51 2518 depends on KUNIT
dcbb2ee2 2519 default KUNIT_ALL_TESTS
d2585f51
VMI
2520 help
2521 Enable this option to test the bitfield functions at boot.
2522
2523 KUnit tests run during boot and output the results to the debug log
2524 in TAP format (http://testanything.org/). Only useful for kernel devs
2525 running the KUnit test harness, and not intended for inclusion into a
2526 production build.
2527
2528 For more information on KUnit and unit tests in general please refer
2529 to the KUnit documentation in Documentation/dev-tools/kunit/.
2530
2531 If unsure, say N.
2532
688eb819
NG
2533config CHECKSUM_KUNIT
2534 tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2535 depends on KUNIT
2536 default KUNIT_ALL_TESTS
2537 help
2538 Enable this option to test the checksum functions at boot.
2539
2540 KUnit tests run during boot and output the results to the debug log
2541 in TAP format (http://testanything.org/). Only useful for kernel devs
2542 running the KUnit test harness, and not intended for inclusion into a
2543 production build.
2544
2545 For more information on KUnit and unit tests in general please refer
2546 to the KUnit documentation in Documentation/dev-tools/kunit/.
2547
2548 If unsure, say N.
2549
0acc968f
IB
2550config HASH_KUNIT_TEST
2551 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2552 depends on KUNIT
2553 default KUNIT_ALL_TESTS
2554 help
2555 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2556 integer (<linux/hash.h>) hash functions on boot.
2557
2558 KUnit tests run during boot and output the results to the debug log
2559 in TAP format (https://testanything.org/). Only useful for kernel devs
2560 running the KUnit test harness, and not intended for inclusion into a
2561 production build.
2562
2563 For more information on KUnit and unit tests in general please refer
2564 to the KUnit documentation in Documentation/dev-tools/kunit/.
2565
2566 This is intended to help people writing architecture-specific
2567 optimized versions. If unsure, say N.
2568
5df38ca6 2569config RESOURCE_KUNIT_TEST
dcbb2ee2 2570 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
5df38ca6 2571 depends on KUNIT
dcbb2ee2 2572 default KUNIT_ALL_TESTS
5df38ca6
AS
2573 help
2574 This builds the resource API unit test.
2575 Tests the logic of API provided by resource.c and ioport.h.
2576 For more information on KUnit and unit tests in general please refer
2577 to the KUnit documentation in Documentation/dev-tools/kunit/.
2578
2579 If unsure, say N.
2580
2cb80dbb 2581config SYSCTL_KUNIT_TEST
5f215aab 2582 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2cb80dbb 2583 depends on KUNIT
5f215aab 2584 default KUNIT_ALL_TESTS
2cb80dbb
IZ
2585 help
2586 This builds the proc sysctl unit test, which runs on boot.
2587 Tests the API contract and implementation correctness of sysctl.
2588 For more information on KUnit and unit tests in general please refer
2589 to the KUnit documentation in Documentation/dev-tools/kunit/.
2590
2591 If unsure, say N.
2592
ea2dd7c0 2593config LIST_KUNIT_TEST
5f215aab 2594 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
ea2dd7c0 2595 depends on KUNIT
5f215aab 2596 default KUNIT_ALL_TESTS
ea2dd7c0
DG
2597 help
2598 This builds the linked list KUnit test suite.
2599 It tests that the API and basic functionality of the list_head type
2600 and associated macros.
2601
2602 KUnit tests run during boot and output the results to the debug log
d89775fc 2603 in TAP format (https://testanything.org/). Only useful for kernel devs
ea2dd7c0
DG
2604 running the KUnit test harness, and not intended for inclusion into a
2605 production build.
2606
2607 For more information on KUnit and unit tests in general please refer
2608 to the KUnit documentation in Documentation/dev-tools/kunit/.
2609
2610 If unsure, say N.
2611
789538c6
RM
2612config HASHTABLE_KUNIT_TEST
2613 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2614 depends on KUNIT
2615 default KUNIT_ALL_TESTS
2616 help
2617 This builds the hashtable KUnit test suite.
2618 It tests the basic functionality of the API defined in
2619 include/linux/hashtable.h. For more information on KUnit and
2620 unit tests in general please refer to the KUnit documentation
2621 in Documentation/dev-tools/kunit/.
2622
2623 If unsure, say N.
2624
33d599f0
MV
2625config LINEAR_RANGES_TEST
2626 tristate "KUnit test for linear_ranges"
2627 depends on KUNIT
2628 select LINEAR_RANGES
2629 help
2630 This builds the linear_ranges unit test, which runs on boot.
2631 Tests the linear_ranges logic correctness.
2632 For more information on KUnit and unit tests in general please refer
7546861a
AS
2633 to the KUnit documentation in Documentation/dev-tools/kunit/.
2634
2635 If unsure, say N.
2636
2637config CMDLINE_KUNIT_TEST
dcbb2ee2 2638 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
7546861a 2639 depends on KUNIT
dcbb2ee2 2640 default KUNIT_ALL_TESTS
7546861a
AS
2641 help
2642 This builds the cmdline API unit test.
2643 Tests the logic of API provided by cmdline.c.
2644 For more information on KUnit and unit tests in general please refer
33d599f0
MV
2645 to the KUnit documentation in Documentation/dev-tools/kunit/.
2646
2647 If unsure, say N.
2648
6d511020 2649config BITS_TEST
dcbb2ee2 2650 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
6d511020 2651 depends on KUNIT
dcbb2ee2 2652 default KUNIT_ALL_TESTS
6d511020
RF
2653 help
2654 This builds the bits unit test.
2655 Tests the logic of macros defined in bits.h.
2656 For more information on KUnit and unit tests in general please refer
2657 to the KUnit documentation in Documentation/dev-tools/kunit/.
2658
2659 If unsure, say N.
2660
1f9f78b1
OG
2661config SLUB_KUNIT_TEST
2662 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2663 depends on SLUB_DEBUG && KUNIT
2664 default KUNIT_ALL_TESTS
2665 help
2666 This builds SLUB allocator unit test.
2667 Tests SLUB cache debugging functionality.
2668 For more information on KUnit and unit tests in general please refer
2669 to the KUnit documentation in Documentation/dev-tools/kunit/.
2670
2671 If unsure, say N.
2672
b6c75c4a
TP
2673config RATIONAL_KUNIT_TEST
2674 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
8ba739ed 2675 depends on KUNIT && RATIONAL
b6c75c4a
TP
2676 default KUNIT_ALL_TESTS
2677 help
2678 This builds the rational math unit test.
2679 For more information on KUnit and unit tests in general please refer
2680 to the KUnit documentation in Documentation/dev-tools/kunit/.
2681
2682 If unsure, say N.
2683
bb95ebbe
KC
2684config MEMCPY_KUNIT_TEST
2685 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2686 depends on KUNIT
2687 default KUNIT_ALL_TESTS
2688 help
2689 Builds unit tests for memcpy(), memmove(), and memset() functions.
2690 For more information on KUnit and unit tests in general please refer
2691 to the KUnit documentation in Documentation/dev-tools/kunit/.
2692
2693 If unsure, say N.
2694
4acf1de3
KC
2695config MEMCPY_SLOW_KUNIT_TEST
2696 bool "Include exhaustive memcpy tests"
2697 depends on MEMCPY_KUNIT_TEST
2698 default y
2699 help
2700 Some memcpy tests are quite exhaustive in checking for overlaps
2701 and bit ranges. These can be very slow, so they are split out
2702 as a separate config, in case they need to be disabled.
2703
addbeea6
BVA
2704config IS_SIGNED_TYPE_KUNIT_TEST
2705 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2706 depends on KUNIT
2707 default KUNIT_ALL_TESTS
2708 help
2709 Builds unit tests for the is_signed_type() macro.
2710
2711 For more information on KUnit and unit tests in general please refer
2712 to the KUnit documentation in Documentation/dev-tools/kunit/.
2713
2714 If unsure, say N.
2715
617f55e2
KC
2716config OVERFLOW_KUNIT_TEST
2717 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2718 depends on KUNIT
2719 default KUNIT_ALL_TESTS
2720 help
2721 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2722 related functions.
2723
2724 For more information on KUnit and unit tests in general please refer
2725 to the KUnit documentation in Documentation/dev-tools/kunit/.
2726
2727 If unsure, say N.
2728
02788ebc
KC
2729config STACKINIT_KUNIT_TEST
2730 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2731 depends on KUNIT
2732 default KUNIT_ALL_TESTS
2733 help
2734 Test if the kernel is zero-initializing stack variables and
2735 padding. Coverage is controlled by compiler flags,
2736 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2737 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2738 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2739
875bfd52
KC
2740config FORTIFY_KUNIT_TEST
2741 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
a9dc8d04 2742 depends on KUNIT
875bfd52
KC
2743 default KUNIT_ALL_TESTS
2744 help
2745 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2746 by the str*() and mem*() family of functions. For testing runtime
2747 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2748
724c299c
ME
2749config HW_BREAKPOINT_KUNIT_TEST
2750 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2751 depends on HAVE_HW_BREAKPOINT
2752 depends on KUNIT=y
2753 default KUNIT_ALL_TESTS
2754 help
2755 Tests for hw_breakpoint constraints accounting.
2756
2757 If unsure, say N.
2758
3bf301e1
KC
2759config STRCAT_KUNIT_TEST
2760 tristate "Test strcat() family of functions at runtime" if !KUNIT_ALL_TESTS
2761 depends on KUNIT
2762 default KUNIT_ALL_TESTS
2763
41eefc46
KC
2764config STRSCPY_KUNIT_TEST
2765 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2766 depends on KUNIT
2767 default KUNIT_ALL_TESTS
2768
fb3d88ab
KC
2769config SIPHASH_KUNIT_TEST
2770 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2771 depends on KUNIT
2772 default KUNIT_ALL_TESTS
2773 help
2774 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2775 functions on boot (or module load).
2776
2777 This is intended to help people writing architecture-specific
2778 optimized versions. If unsure, say N.
2779
e704f93a
DR
2780config TEST_UDELAY
2781 tristate "udelay test driver"
e704f93a
DR
2782 help
2783 This builds the "udelay_test" module that helps to make sure
2784 that udelay() is working properly.
2785
2786 If unsure, say N.
2787
2bf9e0ab
IM
2788config TEST_STATIC_KEYS
2789 tristate "Test static keys"
579e1acb
JB
2790 depends on m
2791 help
2bf9e0ab 2792 Test the static key interfaces.
579e1acb
JB
2793
2794 If unsure, say N.
2795
683263a5
JC
2796config TEST_DYNAMIC_DEBUG
2797 tristate "Test DYNAMIC_DEBUG"
2798 depends on DYNAMIC_DEBUG
2799 help
2800 This module registers a tracer callback to count enabled
2801 pr_debugs in a 'do_debugging' function, then alters their
2802 enablements, calls the function, and compares counts.
2803
2804 If unsure, say N.
2805
d9c6a72d
LR
2806config TEST_KMOD
2807 tristate "kmod stress tester"
d9c6a72d 2808 depends on m
d9c6a72d 2809 depends on NETDEVICES && NET_CORE && INET # for TUN
ae3d6a32 2810 depends on BLOCK
bbd2e05f 2811 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
d9c6a72d
LR
2812 select TEST_LKM
2813 select XFS_FS
2814 select TUN
2815 select BTRFS_FS
2816 help
2817 Test the kernel's module loading mechanism: kmod. kmod implements
2818 support to load modules using the Linux kernel's usermode helper.
2819 This test provides a series of tests against kmod.
2820
2821 Although technically you can either build test_kmod as a module or
2822 into the kernel we disallow building it into the kernel since
2823 it stress tests request_module() and this will very likely cause
2824 some issues by taking over precious threads available from other
2825 module load requests, ultimately this could be fatal.
2826
2827 To run tests run:
2828
2829 tools/testing/selftests/kmod/kmod.sh --help
2830
2831 If unsure, say N.
2832
e4dace36
FF
2833config TEST_DEBUG_VIRTUAL
2834 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2835 depends on DEBUG_VIRTUAL
2836 help
2837 Test the kernel's ability to detect incorrect calls to
2838 virt_to_phys() done against the non-linear part of the
2839 kernel's virtual address map.
2840
2841 If unsure, say N.
2842
ce76d938
AS
2843config TEST_MEMCAT_P
2844 tristate "Test memcat_p() helper function"
2845 help
2846 Test the memcat_p() helper for correctly merging two
2847 pointer arrays together.
2848
2849 If unsure, say N.
2850
a2818ee4
JL
2851config TEST_LIVEPATCH
2852 tristate "Test livepatching"
2853 default n
bae05437 2854 depends on DYNAMIC_DEBUG
a2818ee4
JL
2855 depends on LIVEPATCH
2856 depends on m
2857 help
2858 Test kernel livepatching features for correctness. The tests will
2859 load test modules that will be livepatched in various scenarios.
2860
2861 To run all the livepatching tests:
2862
2863 make -C tools/testing/selftests TARGETS=livepatch run_tests
2864
2865 Alternatively, individual tests may be invoked:
2866
2867 tools/testing/selftests/livepatch/test-callbacks.sh
2868 tools/testing/selftests/livepatch/test-livepatch.sh
2869 tools/testing/selftests/livepatch/test-shadow-vars.sh
2870
2871 If unsure, say N.
2872
0a020d41
JP
2873config TEST_OBJAGG
2874 tristate "Perform selftest on object aggreration manager"
2875 default n
2876 depends on OBJAGG
2877 help
2878 Enable this option to test object aggregation manager on boot
2879 (or module load).
2880
5015a300
AP
2881config TEST_MEMINIT
2882 tristate "Test heap/page initialization"
2883 help
2884 Test if the kernel is zero-initializing heap and page allocations.
2885 This can be useful to test init_on_alloc and init_on_free features.
2886
2887 If unsure, say N.
2888
b2ef9f5a
RC
2889config TEST_HMM
2890 tristate "Test HMM (Heterogeneous Memory Management)"
2891 depends on TRANSPARENT_HUGEPAGE
2892 depends on DEVICE_PRIVATE
2893 select HMM_MIRROR
2894 select MMU_NOTIFIER
2895 help
2896 This is a pseudo device driver solely for testing HMM.
2897 Say M here if you want to build the HMM test module.
2898 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2899
2900 If unsure, say N.
2901
e320d301
MWO
2902config TEST_FREE_PAGES
2903 tristate "Test freeing pages"
2904 help
2905 Test that a memory leak does not occur due to a race between
2906 freeing a block of pages and a speculative page reference.
2907 Loading this module is safe if your kernel has the bug fixed.
2908 If the bug is not fixed, it will leak gigabytes of memory and
2909 probably OOM your system.
2910
4185b3b9
PA
2911config TEST_FPU
2912 tristate "Test floating point operations in kernel space"
2913 depends on X86 && !KCOV_INSTRUMENT_ALL
2914 help
2915 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2916 which will trigger a sequence of floating point operations. This is used
2917 for self-testing floating point control register setting in
2918 kernel_fpu_begin().
2919
2920 If unsure, say N.
2921
1253b9b8
PM
2922config TEST_CLOCKSOURCE_WATCHDOG
2923 tristate "Test clocksource watchdog in kernel space"
2924 depends on CLOCKSOURCE_WATCHDOG
2925 help
2926 Enable this option to create a kernel module that will trigger
2927 a test of the clocksource watchdog. This module may be loaded
2928 via modprobe or insmod in which case it will run upon being
2929 loaded, or it may be built in, in which case it will run
2930 shortly after boot.
2931
2932 If unsure, say N.
2933
d3deafaa 2934endif # RUNTIME_TESTING_MENU
cc3fa840 2935
dce44566
AK
2936config ARCH_USE_MEMTEST
2937 bool
2938 help
2939 An architecture should select this when it uses early_memtest()
2940 during boot process.
2941
cc3fa840
RD
2942config MEMTEST
2943 bool "Memtest"
dce44566 2944 depends on ARCH_USE_MEMTEST
a7f7f624 2945 help
cc3fa840 2946 This option adds a kernel parameter 'memtest', which allows memtest
dce44566 2947 to be set and executed.
cc3fa840
RD
2948 memtest=0, mean disabled; -- default
2949 memtest=1, mean do 1 test pattern;
2950 ...
2951 memtest=17, mean do 17 test patterns.
2952 If you are unsure how to answer this question, answer N.
2953
21266be9 2954
06ec64b8 2955
af9ca6f9
BB
2956config HYPERV_TESTING
2957 bool "Microsoft Hyper-V driver testing"
2958 default n
2959 depends on HYPERV && DEBUG_FS
2960 help
2961 Select this option to enable Hyper-V vmbus testing.
2962
045f6d79
CD
2963endmenu # "Kernel Testing and Coverage"
2964
2f7ab126
MO
2965menu "Rust hacking"
2966
2967config RUST_DEBUG_ASSERTIONS
2968 bool "Debug assertions"
2969 depends on RUST
2970 help
2971 Enables rustc's `-Cdebug-assertions` codegen option.
2972
2973 This flag lets you turn `cfg(debug_assertions)` conditional
2974 compilation on or off. This can be used to enable extra debugging
2975 code in development but not in production. For example, it controls
2976 the behavior of the standard library's `debug_assert!` macro.
2977
2978 Note that this will apply to all Rust code, including `core`.
2979
2980 If unsure, say N.
2981
2982config RUST_OVERFLOW_CHECKS
2983 bool "Overflow checks"
2984 default y
2985 depends on RUST
2986 help
2987 Enables rustc's `-Coverflow-checks` codegen option.
2988
2989 This flag allows you to control the behavior of runtime integer
2990 overflow. When overflow-checks are enabled, a Rust panic will occur
2991 on overflow.
2992
2993 Note that this will apply to all Rust code, including `core`.
2994
2995 If unsure, say Y.
2996
ecaa6ddf
GG
2997config RUST_BUILD_ASSERT_ALLOW
2998 bool "Allow unoptimized build-time assertions"
2999 depends on RUST
3000 help
3001 Controls how are `build_error!` and `build_assert!` handled during build.
3002
3003 If calls to them exist in the binary, it may indicate a violated invariant
3004 or that the optimizer failed to verify the invariant during compilation.
3005
3006 This should not happen, thus by default the build is aborted. However,
3007 as an escape hatch, you can choose Y here to ignore them during build
3008 and let the check be carried at runtime (with `panic!` being called if
3009 the check fails).
3010
3011 If unsure, say N.
3012
2f7ab126
MO
3013endmenu # "Rust"
3014
06ec64b8 3015endmenu # Kernel hacking