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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
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504 bool "Force all function address 64B aligned"
505 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
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
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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
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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
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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
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IM
739config DEBUG_OBJECTS_ENABLE_DEFAULT
740 int "debug_objects bootup default value (0-1)"
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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
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CM
755config HAVE_DEBUG_KMEMLEAK
756 bool
757
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CM
758config DEBUG_KMEMLEAK
759 bool "Kernel memory leak detector"
525c1f92 760 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
79e0d9bd 761 select DEBUG_FS
3bba00d7
CM
762 select STACKTRACE if STACKTRACE_SUPPORT
763 select KALLSYMS
b60e26a2 764 select CRC32
56a61617 765 select STACKDEPOT
993f57e0 766 select STACKDEPOT_ALWAYS_INIT if !DEBUG_KMEMLEAK_DEFAULT_OFF
3bba00d7
CM
767 help
768 Say Y here if you want to enable the memory leak
769 detector. The memory allocation/freeing is traced in a way
770 similar to the Boehm's conservative garbage collector, the
771 difference being that the orphan objects are not freed but
772 only shown in /sys/kernel/debug/kmemleak. Enabling this
773 feature will introduce an overhead to memory
700199b0 774 allocations. See Documentation/dev-tools/kmemleak.rst for more
3bba00d7
CM
775 details.
776
0610c8a8
DH
777 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
778 of finding leaks due to the slab objects poisoning.
779
780 In order to access the kmemleak file, debugfs needs to be
781 mounted (usually at /sys/kernel/debug).
782
c5665868
CM
783config DEBUG_KMEMLEAK_MEM_POOL_SIZE
784 int "Kmemleak memory pool size"
0610c8a8 785 depends on DEBUG_KMEMLEAK
c59180ae 786 range 200 1000000
b751c52b 787 default 16000
0610c8a8
DH
788 help
789 Kmemleak must track all the memory allocations to avoid
790 reporting false positives. Since memory may be allocated or
c5665868
CM
791 freed before kmemleak is fully initialised, use a static pool
792 of metadata objects to track such callbacks. After kmemleak is
793 fully initialised, this memory pool acts as an emergency one
794 if slab allocations fail.
0610c8a8
DH
795
796config DEBUG_KMEMLEAK_TEST
797 tristate "Simple test for the kernel memory leak detector"
798 depends on DEBUG_KMEMLEAK && m
799 help
800 This option enables a module that explicitly leaks memory.
801
802 If unsure, say N.
803
804config DEBUG_KMEMLEAK_DEFAULT_OFF
805 bool "Default kmemleak to off"
806 depends on DEBUG_KMEMLEAK
807 help
808 Say Y here to disable kmemleak by default. It can then be enabled
809 on the command line via kmemleak=on.
810
d53ce042
SK
811config DEBUG_KMEMLEAK_AUTO_SCAN
812 bool "Enable kmemleak auto scan thread on boot up"
813 default y
814 depends on DEBUG_KMEMLEAK
815 help
816 Depending on the cpu, kmemleak scan may be cpu intensive and can
817 stall user tasks at times. This option enables/disables automatic
818 kmemleak scan at boot up.
819
820 Say N here to disable kmemleak auto scan thread to stop automatic
821 scanning. Disabling this option disables automatic reporting of
822 memory leaks.
823
824 If unsure, say Y.
825
0610c8a8
DH
826config DEBUG_STACK_USAGE
827 bool "Stack utilization instrumentation"
6c31da34 828 depends on DEBUG_KERNEL && !IA64
0610c8a8
DH
829 help
830 Enables the display of the minimum amount of free stack which each
831 task has ever had available in the sysrq-T and sysrq-P debug output.
832
833 This option will slow down process creation somewhat.
834
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CD
835config SCHED_STACK_END_CHECK
836 bool "Detect stack corruption on calls to schedule()"
837 depends on DEBUG_KERNEL
838 default n
839 help
840 This option checks for a stack overrun on calls to schedule().
841 If the stack end location is found to be over written always panic as
842 the content of the corrupted region can no longer be trusted.
843 This is to ensure no erroneous behaviour occurs which could result in
844 data corruption or a sporadic crash at a later stage once the region
845 is examined. The runtime overhead introduced is minimal.
846
399145f9
AK
847config ARCH_HAS_DEBUG_VM_PGTABLE
848 bool
849 help
850 An architecture should select this when it can successfully
851 build and run DEBUG_VM_PGTABLE.
852
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TG
853config DEBUG_VM_IRQSOFF
854 def_bool DEBUG_VM && !PREEMPT_RT
855
0610c8a8
DH
856config DEBUG_VM
857 bool "Debug VM"
858 depends on DEBUG_KERNEL
859 help
860 Enable this to turn on extended checks in the virtual-memory system
68d4b3df 861 that may impact performance.
0610c8a8
DH
862
863 If unsure, say N.
864
54a611b6
LH
865config DEBUG_VM_MAPLE_TREE
866 bool "Debug VM maple trees"
4f115147 867 depends on DEBUG_VM
54a611b6 868 select DEBUG_MAPLE_TREE
4f115147 869 help
54a611b6 870 Enable VM maple tree debugging information and extra validations.
4f115147
DB
871
872 If unsure, say N.
873
0610c8a8
DH
874config DEBUG_VM_RB
875 bool "Debug VM red-black trees"
876 depends on DEBUG_VM
877 help
a663dad6 878 Enable VM red-black tree debugging information and extra validations.
0610c8a8
DH
879
880 If unsure, say N.
881
95ad9755
KS
882config DEBUG_VM_PGFLAGS
883 bool "Debug page-flags operations"
884 depends on DEBUG_VM
885 help
886 Enables extra validation on page flags operations.
887
888 If unsure, say N.
889
399145f9
AK
890config DEBUG_VM_PGTABLE
891 bool "Debug arch page table for semantics compliance"
892 depends on MMU
893 depends on ARCH_HAS_DEBUG_VM_PGTABLE
894 default y if DEBUG_VM
895 help
896 This option provides a debug method which can be used to test
897 architecture page table helper functions on various platforms in
898 verifying if they comply with expected generic MM semantics. This
899 will help architecture code in making sure that any changes or
900 new additions of these helpers still conform to expected
901 semantics of the generic MM. Platforms will have to opt in for
902 this through ARCH_HAS_DEBUG_VM_PGTABLE.
903
904 If unsure, say N.
905
fa5b6ec9
LA
906config ARCH_HAS_DEBUG_VIRTUAL
907 bool
908
0610c8a8
DH
909config DEBUG_VIRTUAL
910 bool "Debug VM translations"
fa5b6ec9 911 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
0610c8a8
DH
912 help
913 Enable some costly sanity checks in virtual to page code. This can
914 catch mistakes with virt_to_page() and friends.
915
916 If unsure, say N.
917
918config DEBUG_NOMMU_REGIONS
919 bool "Debug the global anon/private NOMMU mapping region tree"
920 depends on DEBUG_KERNEL && !MMU
921 help
922 This option causes the global tree of anonymous and private mapping
923 regions to be regularly checked for invalid topology.
924
925config DEBUG_MEMORY_INIT
926 bool "Debug memory initialisation" if EXPERT
927 default !EXPERT
928 help
929 Enable this for additional checks during memory initialisation.
930 The sanity checks verify aspects of the VM such as the memory model
931 and other information provided by the architecture. Verbose
932 information will be printed at KERN_DEBUG loglevel depending
933 on the mminit_loglevel= command-line option.
934
935 If unsure, say Y
936
937config MEMORY_NOTIFIER_ERROR_INJECT
938 tristate "Memory hotplug notifier error injection module"
50f9481e 939 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
0610c8a8
DH
940 help
941 This option provides the ability to inject artificial errors to
942 memory hotplug notifier chain callbacks. It is controlled through
943 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
944
945 If the notifier call chain should be failed with some events
946 notified, write the error code to "actions/<notifier event>/error".
947
948 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
949
950 # cd /sys/kernel/debug/notifier-error-inject/memory
951 # echo -12 > actions/MEM_GOING_OFFLINE/error
952 # echo offline > /sys/devices/system/memory/memoryXXX/state
953 bash: echo: write error: Cannot allocate memory
954
955 To compile this code as a module, choose M here: the module will
956 be called memory-notifier-error-inject.
957
958 If unsure, say N.
959
960config DEBUG_PER_CPU_MAPS
961 bool "Debug access to per_cpu maps"
962 depends on DEBUG_KERNEL
963 depends on SMP
964 help
965 Say Y to verify that the per_cpu map being accessed has
966 been set up. This adds a fair amount of code to kernel memory
967 and decreases performance.
968
969 Say N if unsure.
970
6e799cb6
TG
971config DEBUG_KMAP_LOCAL
972 bool "Debug kmap_local temporary mappings"
973 depends on DEBUG_KERNEL && KMAP_LOCAL
974 help
975 This option enables additional error checking for the kmap_local
976 infrastructure. Disable for production use.
977
0e91a0c6
TG
978config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
979 bool
980
981config DEBUG_KMAP_LOCAL_FORCE_MAP
982 bool "Enforce kmap_local temporary mappings"
983 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
984 select KMAP_LOCAL
985 select DEBUG_KMAP_LOCAL
986 help
987 This option enforces temporary mappings through the kmap_local
988 mechanism for non-highmem pages and on non-highmem systems.
989 Disable this for production systems!
990
0610c8a8
DH
991config DEBUG_HIGHMEM
992 bool "Highmem debugging"
993 depends on DEBUG_KERNEL && HIGHMEM
0e91a0c6 994 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
6e799cb6 995 select DEBUG_KMAP_LOCAL
0610c8a8 996 help
b1357c9f
GU
997 This option enables additional error checking for high memory
998 systems. Disable for production systems.
0610c8a8
DH
999
1000config HAVE_DEBUG_STACKOVERFLOW
1001 bool
1002
1003config DEBUG_STACKOVERFLOW
1004 bool "Check for stack overflows"
1005 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
a7f7f624 1006 help
0610c8a8 1007 Say Y here if you want to check for overflows of kernel, IRQ
edb0ec07 1008 and exception stacks (if your architecture uses them). This
0610c8a8
DH
1009 option will show detailed messages if free stack space drops
1010 below a certain limit.
1011
1012 These kinds of bugs usually occur when call-chains in the
1013 kernel get too deep, especially when interrupts are
1014 involved.
1015
1016 Use this in cases where you see apparently random memory
1017 corruption, especially if it appears in 'struct thread_info'
1018
1019 If in doubt, say "N".
1020
0b24becc 1021source "lib/Kconfig.kasan"
0ce20dd8 1022source "lib/Kconfig.kfence"
f80be457 1023source "lib/Kconfig.kmsan"
0b24becc 1024
0610c8a8
DH
1025endmenu # "Memory Debugging"
1026
a304e1b8
DW
1027config DEBUG_SHIRQ
1028 bool "Debug shared IRQ handlers"
0244ad00 1029 depends on DEBUG_KERNEL
a304e1b8 1030 help
0a2fae2a
WS
1031 Enable this to generate a spurious interrupt just before a shared
1032 interrupt handler is deregistered (generating one when registering
1033 is currently disabled). Drivers need to handle this correctly. Some
1034 don't and need to be caught.
a304e1b8 1035
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CD
1036menu "Debug Oops, Lockups and Hangs"
1037
1038config PANIC_ON_OOPS
1039 bool "Panic on Oops"
1040 help
1041 Say Y here to enable the kernel to panic when it oopses. This
1042 has the same effect as setting oops=panic on the kernel command
1043 line.
1044
1045 This feature is useful to ensure that the kernel does not do
1046 anything erroneous after an oops which could result in data
1047 corruption or other issues.
1048
1049 Say N if unsure.
1050
1051config PANIC_ON_OOPS_VALUE
1052 int
1053 range 0 1
1054 default 0 if !PANIC_ON_OOPS
1055 default 1 if PANIC_ON_OOPS
1056
1057config PANIC_TIMEOUT
1058 int "panic timeout"
1059 default 0
1060 help
9d5b134f 1061 Set the timeout value (in seconds) until a reboot occurs when
f43a289d
CD
1062 the kernel panics. If n = 0, then we wait forever. A timeout
1063 value n > 0 will wait n seconds before rebooting, while a timeout
1064 value n < 0 will reboot immediately.
92aef8fb 1065
58687acb 1066config LOCKUP_DETECTOR
05a4a952
NP
1067 bool
1068
1069config SOFTLOCKUP_DETECTOR
1070 bool "Detect Soft Lockups"
dea20a3f 1071 depends on DEBUG_KERNEL && !S390
05a4a952 1072 select LOCKUP_DETECTOR
8446f1d3 1073 help
58687acb 1074 Say Y here to enable the kernel to act as a watchdog to detect
05a4a952 1075 soft lockups.
58687acb
DZ
1076
1077 Softlockups are bugs that cause the kernel to loop in kernel
5f329089 1078 mode for more than 20 seconds, without giving other tasks a
58687acb
DZ
1079 chance to run. The current stack trace is displayed upon
1080 detection and the system will stay locked up.
8446f1d3 1081
5f00ae0d
RD
1082config BOOTPARAM_SOFTLOCKUP_PANIC
1083 bool "Panic (Reboot) On Soft Lockups"
1084 depends on SOFTLOCKUP_DETECTOR
1085 help
1086 Say Y here to enable the kernel to panic on "soft lockups",
1087 which are bugs that cause the kernel to loop in kernel
1088 mode for more than 20 seconds (configurable using the watchdog_thresh
1089 sysctl), without giving other tasks a chance to run.
1090
1091 The panic can be used in combination with panic_timeout,
1092 to cause the system to reboot automatically after a
1093 lockup has been detected. This feature is useful for
1094 high-availability systems that have uptime guarantees and
1095 where a lockup must be resolved ASAP.
1096
1097 Say N if unsure.
1098
05a4a952
NP
1099config HARDLOCKUP_DETECTOR_PERF
1100 bool
1101 select SOFTLOCKUP_DETECTOR
1102
7edaeb68
TG
1103#
1104# Enables a timestamp based low pass filter to compensate for perf based
1105# hard lockup detection which runs too fast due to turbo modes.
1106#
1107config HARDLOCKUP_CHECK_TIMESTAMP
1108 bool
1109
05a4a952
NP
1110#
1111# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1112# lockup detector rather than the perf based detector.
1113#
1114config HARDLOCKUP_DETECTOR
1115 bool "Detect Hard Lockups"
1116 depends on DEBUG_KERNEL && !S390
1117 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1118 select LOCKUP_DETECTOR
1119 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
05a4a952
NP
1120 help
1121 Say Y here to enable the kernel to act as a watchdog to detect
1122 hard lockups.
1123
58687acb 1124 Hardlockups are bugs that cause the CPU to loop in kernel mode
5f329089 1125 for more than 10 seconds, without letting other interrupts have a
58687acb
DZ
1126 chance to run. The current stack trace is displayed upon detection
1127 and the system will stay locked up.
8446f1d3 1128
fef2c9bc
DZ
1129config BOOTPARAM_HARDLOCKUP_PANIC
1130 bool "Panic (Reboot) On Hard Lockups"
8f1f66ed 1131 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
1132 help
1133 Say Y here to enable the kernel to panic on "hard lockups",
1134 which are bugs that cause the kernel to loop in kernel
5f329089
FLVC
1135 mode with interrupts disabled for more than 10 seconds (configurable
1136 using the watchdog_thresh sysctl).
fef2c9bc
DZ
1137
1138 Say N if unsure.
1139
e162b39a
MSB
1140config DETECT_HUNG_TASK
1141 bool "Detect Hung Tasks"
1142 depends on DEBUG_KERNEL
05a4a952 1143 default SOFTLOCKUP_DETECTOR
e162b39a 1144 help
0610c8a8
DH
1145 Say Y here to enable the kernel to detect "hung tasks",
1146 which are bugs that cause the task to be stuck in
96b03ab8 1147 uninterruptible "D" state indefinitely.
1da177e4 1148
0610c8a8
DH
1149 When a hung task is detected, the kernel will print the
1150 current stack trace (which you should report), but the
1151 task will stay in uninterruptible state. If lockdep is
1152 enabled then all held locks will also be reported. This
1153 feature has negligible overhead.
871751e2 1154
0610c8a8
DH
1155config DEFAULT_HUNG_TASK_TIMEOUT
1156 int "Default timeout for hung task detection (in seconds)"
1157 depends on DETECT_HUNG_TASK
1158 default 120
f0630fff 1159 help
0610c8a8
DH
1160 This option controls the default timeout (in seconds) used
1161 to determine when a task has become non-responsive and should
1162 be considered hung.
f0630fff 1163
0610c8a8
DH
1164 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1165 sysctl or by writing a value to
1166 /proc/sys/kernel/hung_task_timeout_secs.
8ff12cfc 1167
0610c8a8
DH
1168 A timeout of 0 disables the check. The default is two minutes.
1169 Keeping the default should be fine in most cases.
b69ec42b 1170
0610c8a8
DH
1171config BOOTPARAM_HUNG_TASK_PANIC
1172 bool "Panic (Reboot) On Hung Tasks"
1173 depends on DETECT_HUNG_TASK
3bba00d7 1174 help
0610c8a8
DH
1175 Say Y here to enable the kernel to panic on "hung tasks",
1176 which are bugs that cause the kernel to leave a task stuck
1177 in uninterruptible "D" state.
3bba00d7 1178
0610c8a8
DH
1179 The panic can be used in combination with panic_timeout,
1180 to cause the system to reboot automatically after a
1181 hung task has been detected. This feature is useful for
1182 high-availability systems that have uptime guarantees and
1183 where a hung tasks must be resolved ASAP.
bf96d1e3 1184
0610c8a8 1185 Say N if unsure.
bf96d1e3 1186
82607adc
TH
1187config WQ_WATCHDOG
1188 bool "Detect Workqueue Stalls"
1189 depends on DEBUG_KERNEL
1190 help
1191 Say Y here to enable stall detection on workqueues. If a
1192 worker pool doesn't make forward progress on a pending work
1193 item for over a given amount of time, 30s by default, a
1194 warning message is printed along with dump of workqueue
1195 state. This can be configured through kernel parameter
1196 "workqueue.watchdog_thresh" and its sysfs counterpart.
1197
30428ef5
KK
1198config TEST_LOCKUP
1199 tristate "Test module to generate lockups"
63646bc9 1200 depends on m
30428ef5
KK
1201 help
1202 This builds the "test_lockup" module that helps to make sure
1203 that watchdogs and lockup detectors are working properly.
1204
1205 Depending on module parameters it could emulate soft or hard
1206 lockup, "hung task", or locking arbitrary lock for a long time.
1207 Also it could generate series of lockups with cooling-down periods.
1208
1209 If unsure, say N.
1210
92aef8fb
DH
1211endmenu # "Debug lockups and hangs"
1212
ebebdd09 1213menu "Scheduler Debugging"
5800dc3c 1214
0610c8a8
DH
1215config SCHED_DEBUG
1216 bool "Collect scheduler debugging info"
1217 depends on DEBUG_KERNEL && PROC_FS
1218 default y
0822ee4a 1219 help
1e90e35b 1220 If you say Y here, the /sys/kernel/debug/sched file will be provided
0610c8a8
DH
1221 that can help debug the scheduler. The runtime overhead of this
1222 option is minimal.
0822ee4a 1223
f6db8347
NR
1224config SCHED_INFO
1225 bool
1226 default n
1227
0610c8a8
DH
1228config SCHEDSTATS
1229 bool "Collect scheduler statistics"
1230 depends on DEBUG_KERNEL && PROC_FS
f6db8347 1231 select SCHED_INFO
0610c8a8
DH
1232 help
1233 If you say Y here, additional code will be inserted into the
1234 scheduler and related routines to collect statistics about
1235 scheduler behavior and provide them in /proc/schedstat. These
1236 stats may be useful for both tuning and debugging the scheduler
1237 If you aren't debugging the scheduler or trying to tune a specific
1238 application, you can say N to avoid the very slight overhead
1239 this adds.
0822ee4a 1240
ebebdd09 1241endmenu
0d9e2632 1242
3c17ad19
JS
1243config DEBUG_TIMEKEEPING
1244 bool "Enable extra timekeeping sanity checking"
1245 help
1246 This option will enable additional timekeeping sanity checks
1247 which may be helpful when diagnosing issues where timekeeping
1248 problems are suspected.
1249
1250 This may include checks in the timekeeping hotpaths, so this
1251 option may have a (very small) performance impact to some
1252 workloads.
1253
1254 If unsure, say N.
1255
1da177e4
LT
1256config DEBUG_PREEMPT
1257 bool "Debug preemptible kernel"
9f472869 1258 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1da177e4
LT
1259 default y
1260 help
1261 If you say Y here then the kernel will use a debug variant of the
1262 commonly used smp_processor_id() function and will print warnings
1263 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1264 will detect preemption count underflows.
1265
9eade16b
DH
1266menu "Lock Debugging (spinlocks, mutexes, etc...)"
1267
f07cbebb
WL
1268config LOCK_DEBUGGING_SUPPORT
1269 bool
1270 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1271 default y
1272
19193bca
WL
1273config PROVE_LOCKING
1274 bool "Lock debugging: prove locking correctness"
1275 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1276 select LOCKDEP
1277 select DEBUG_SPINLOCK
bb630f9f 1278 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca 1279 select DEBUG_RT_MUTEXES if RT_MUTEXES
c71fd893 1280 select DEBUG_RWSEMS
19193bca
WL
1281 select DEBUG_WW_MUTEX_SLOWPATH
1282 select DEBUG_LOCK_ALLOC
8fd8ad5c 1283 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
19193bca
WL
1284 select TRACE_IRQFLAGS
1285 default n
1286 help
1287 This feature enables the kernel to prove that all locking
1288 that occurs in the kernel runtime is mathematically
1289 correct: that under no circumstance could an arbitrary (and
1290 not yet triggered) combination of observed locking
1291 sequences (on an arbitrary number of CPUs, running an
1292 arbitrary number of tasks and interrupt contexts) cause a
1293 deadlock.
1294
1295 In short, this feature enables the kernel to report locking
1296 related deadlocks before they actually occur.
1297
1298 The proof does not depend on how hard and complex a
1299 deadlock scenario would be to trigger: how many
1300 participant CPUs, tasks and irq-contexts would be needed
1301 for it to trigger. The proof also does not depend on
1302 timing: if a race and a resulting deadlock is possible
1303 theoretically (no matter how unlikely the race scenario
1304 is), it will be proven so and will immediately be
1305 reported by the kernel (once the event is observed that
1306 makes the deadlock theoretically possible).
1307
1308 If a deadlock is impossible (i.e. the locking rules, as
1309 observed by the kernel, are mathematically correct), the
1310 kernel reports nothing.
1311
1312 NOTE: this feature can also be enabled for rwlocks, mutexes
1313 and rwsems - in which case all dependencies between these
1314 different locking variants are observed and mapped too, and
1315 the proof of observed correctness is also maintained for an
1316 arbitrary combination of these separate locking variants.
1317
387b1468 1318 For more details, see Documentation/locking/lockdep-design.rst.
19193bca 1319
de8f5e4f
PZ
1320config PROVE_RAW_LOCK_NESTING
1321 bool "Enable raw_spinlock - spinlock nesting checks"
1322 depends on PROVE_LOCKING
1323 default n
1324 help
1325 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1326 that the lock nesting rules for PREEMPT_RT enabled kernels are
1327 not violated.
1328
1329 NOTE: There are known nesting problems. So if you enable this
1330 option expect lockdep splats until these problems have been fully
1331 addressed which is work in progress. This config switch allows to
1332 identify and analyze these problems. It will be removed and the
9dbbc3b9 1333 check permanently enabled once the main issues have been fixed.
de8f5e4f
PZ
1334
1335 If unsure, select N.
1336
19193bca
WL
1337config LOCK_STAT
1338 bool "Lock usage statistics"
1339 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1340 select LOCKDEP
1341 select DEBUG_SPINLOCK
bb630f9f 1342 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca
WL
1343 select DEBUG_RT_MUTEXES if RT_MUTEXES
1344 select DEBUG_LOCK_ALLOC
1345 default n
1346 help
1347 This feature enables tracking lock contention points
1348
387b1468 1349 For more details, see Documentation/locking/lockstat.rst
19193bca
WL
1350
1351 This also enables lock events required by "perf lock",
1352 subcommand of perf.
1353 If you want to use "perf lock", you also need to turn on
1354 CONFIG_EVENT_TRACING.
1355
1356 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1357 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1358
e7eebaf6
IM
1359config DEBUG_RT_MUTEXES
1360 bool "RT Mutex debugging, deadlock detection"
e7eebaf6
IM
1361 depends on DEBUG_KERNEL && RT_MUTEXES
1362 help
1363 This allows rt mutex semantics violations and rt mutex related
1364 deadlocks (lockups) to be detected and reported automatically.
1365
1da177e4 1366config DEBUG_SPINLOCK
4d9f34ad 1367 bool "Spinlock and rw-lock debugging: basic checks"
1da177e4 1368 depends on DEBUG_KERNEL
e335e3eb 1369 select UNINLINE_SPIN_UNLOCK
1da177e4
LT
1370 help
1371 Say Y here and build SMP to catch missing spinlock initialization
1372 and certain other kinds of spinlock errors commonly made. This is
1373 best used in conjunction with the NMI watchdog so that spinlock
1374 deadlocks are also debuggable.
1375
4d9f34ad
IM
1376config DEBUG_MUTEXES
1377 bool "Mutex debugging: basic checks"
bb630f9f 1378 depends on DEBUG_KERNEL && !PREEMPT_RT
4d9f34ad
IM
1379 help
1380 This feature allows mutex semantics violations to be detected and
1381 reported.
1382
23010027
DV
1383config DEBUG_WW_MUTEX_SLOWPATH
1384 bool "Wait/wound mutex debugging: Slowpath testing"
f07cbebb 1385 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
23010027
DV
1386 select DEBUG_LOCK_ALLOC
1387 select DEBUG_SPINLOCK
bb630f9f
TG
1388 select DEBUG_MUTEXES if !PREEMPT_RT
1389 select DEBUG_RT_MUTEXES if PREEMPT_RT
23010027
DV
1390 help
1391 This feature enables slowpath testing for w/w mutex users by
1392 injecting additional -EDEADLK wound/backoff cases. Together with
1393 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1394 will test all possible w/w mutex interface abuse with the
1395 exception of simply not acquiring all the required locks.
4d692373
RC
1396 Note that this feature can introduce significant overhead, so
1397 it really should not be enabled in a production or distro kernel,
1398 even a debug kernel. If you are a driver writer, enable it. If
1399 you are a distro, do not.
23010027 1400
5149cbac
WL
1401config DEBUG_RWSEMS
1402 bool "RW Semaphore debugging: basic checks"
c71fd893 1403 depends on DEBUG_KERNEL
5149cbac 1404 help
c71fd893
WL
1405 This debugging feature allows mismatched rw semaphore locks
1406 and unlocks to be detected and reported.
5149cbac 1407
4d9f34ad
IM
1408config DEBUG_LOCK_ALLOC
1409 bool "Lock debugging: detect incorrect freeing of live locks"
f07cbebb 1410 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1411 select DEBUG_SPINLOCK
bb630f9f 1412 select DEBUG_MUTEXES if !PREEMPT_RT
f5694788 1413 select DEBUG_RT_MUTEXES if RT_MUTEXES
4d9f34ad
IM
1414 select LOCKDEP
1415 help
1416 This feature will check whether any held lock (spinlock, rwlock,
1417 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1418 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1419 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1420 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1421 held during task exit.
1422
4d9f34ad
IM
1423config LOCKDEP
1424 bool
f07cbebb 1425 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1426 select STACKTRACE
4d9f34ad
IM
1427 select KALLSYMS
1428 select KALLSYMS_ALL
1429
395102db
DJ
1430config LOCKDEP_SMALL
1431 bool
1432
5dc33592
TH
1433config LOCKDEP_BITS
1434 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1435 depends on LOCKDEP && !LOCKDEP_SMALL
1436 range 10 30
1437 default 15
1438 help
1439 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1440
1441config LOCKDEP_CHAINS_BITS
1442 int "Bitsize for MAX_LOCKDEP_CHAINS"
1443 depends on LOCKDEP && !LOCKDEP_SMALL
1444 range 10 30
1445 default 16
1446 help
1447 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1448
1449config LOCKDEP_STACK_TRACE_BITS
1450 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1451 depends on LOCKDEP && !LOCKDEP_SMALL
1452 range 10 30
1453 default 19
1454 help
1455 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1456
1457config LOCKDEP_STACK_TRACE_HASH_BITS
1458 int "Bitsize for STACK_TRACE_HASH_SIZE"
1459 depends on LOCKDEP && !LOCKDEP_SMALL
1460 range 10 30
1461 default 14
1462 help
1463 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1464
1465config LOCKDEP_CIRCULAR_QUEUE_BITS
1466 int "Bitsize for elements in circular_queue struct"
1467 depends on LOCKDEP
1468 range 10 30
1469 default 12
1470 help
1471 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1472
4d9f34ad
IM
1473config DEBUG_LOCKDEP
1474 bool "Lock dependency engine debugging"
517e7aa5 1475 depends on DEBUG_KERNEL && LOCKDEP
997acaf6 1476 select DEBUG_IRQFLAGS
4d9f34ad
IM
1477 help
1478 If you say Y here, the lock dependency engine will do
1479 additional runtime checks to debug itself, at the price
1480 of more runtime overhead.
1481
d902db1e
FW
1482config DEBUG_ATOMIC_SLEEP
1483 bool "Sleep inside atomic section checking"
e8f7c70f 1484 select PREEMPT_COUNT
1da177e4 1485 depends on DEBUG_KERNEL
87a4c375 1486 depends on !ARCH_NO_PREEMPT
1da177e4
LT
1487 help
1488 If you say Y here, various routines which may sleep will become very
d902db1e
FW
1489 noisy if they are called inside atomic sections: when a spinlock is
1490 held, inside an rcu read side critical section, inside preempt disabled
1491 sections, inside an interrupt, etc...
1da177e4 1492
cae2ed9a
IM
1493config DEBUG_LOCKING_API_SELFTESTS
1494 bool "Locking API boot-time self-tests"
1495 depends on DEBUG_KERNEL
1496 help
1497 Say Y here if you want the kernel to run a short self-test during
1498 bootup. The self-test checks whether common types of locking bugs
1499 are detected by debugging mechanisms or not. (if you disable
9dbbc3b9 1500 lock debugging then those bugs won't be detected of course.)
cae2ed9a
IM
1501 The following locking APIs are covered: spinlocks, rwlocks,
1502 mutexes and rwsems.
1503
0af3fe1e
PM
1504config LOCK_TORTURE_TEST
1505 tristate "torture tests for locking"
1506 depends on DEBUG_KERNEL
1507 select TORTURE_TEST
0af3fe1e
PM
1508 help
1509 This option provides a kernel module that runs torture tests
1510 on kernel locking primitives. The kernel module may be built
1511 after the fact on the running kernel to be tested, if desired.
1512
1513 Say Y here if you want kernel locking-primitive torture tests
1514 to be built into the kernel.
1515 Say M if you want these torture tests to build as a module.
1516 Say N if you are unsure.
1517
f2a5fec1
CW
1518config WW_MUTEX_SELFTEST
1519 tristate "Wait/wound mutex selftests"
1520 help
1521 This option provides a kernel module that runs tests on the
1522 on the struct ww_mutex locking API.
1523
1524 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1525 with this test harness.
1526
1527 Say M if you want these self tests to build as a module.
1528 Say N if you are unsure.
1529
e9d338a0
PM
1530config SCF_TORTURE_TEST
1531 tristate "torture tests for smp_call_function*()"
1532 depends on DEBUG_KERNEL
1533 select TORTURE_TEST
1534 help
1535 This option provides a kernel module that runs torture tests
1536 on the smp_call_function() family of primitives. The kernel
1537 module may be built after the fact on the running kernel to
1538 be tested, if desired.
1539
35feb604
PM
1540config CSD_LOCK_WAIT_DEBUG
1541 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1542 depends on DEBUG_KERNEL
1543 depends on 64BIT
1544 default n
1545 help
1546 This option enables debug prints when CPUs are slow to respond
1547 to the smp_call_function*() IPI wrappers. These debug prints
1548 include the IPI handler function currently executing (if any)
1549 and relevant stack traces.
1550
9eade16b 1551endmenu # lock debugging
8637c099 1552
9eade16b 1553config TRACE_IRQFLAGS
ed004953 1554 depends on TRACE_IRQFLAGS_SUPPORT
9eade16b 1555 bool
5ca43f6c 1556 help
9eade16b
DH
1557 Enables hooks to interrupt enabling and disabling for
1558 either tracing or lock debugging.
5ca43f6c 1559
ed004953 1560config TRACE_IRQFLAGS_NMI
1561 def_bool y
1562 depends on TRACE_IRQFLAGS
1563 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1564
997acaf6
MR
1565config DEBUG_IRQFLAGS
1566 bool "Debug IRQ flag manipulation"
1567 help
1568 Enables checks for potentially unsafe enabling or disabling of
1569 interrupts, such as calling raw_local_irq_restore() when interrupts
1570 are enabled.
1571
8637c099 1572config STACKTRACE
0c38e1fe 1573 bool "Stack backtrace support"
8637c099 1574 depends on STACKTRACE_SUPPORT
0c38e1fe
DJ
1575 help
1576 This option causes the kernel to create a /proc/pid/stack for
1577 every process, showing its current stack trace.
1578 It is also used by various kernel debugging features that require
1579 stack trace generation.
5ca43f6c 1580
eecabf56
TT
1581config WARN_ALL_UNSEEDED_RANDOM
1582 bool "Warn for all uses of unseeded randomness"
1583 default n
d06bfd19
JD
1584 help
1585 Some parts of the kernel contain bugs relating to their use of
1586 cryptographically secure random numbers before it's actually possible
1587 to generate those numbers securely. This setting ensures that these
1588 flaws don't go unnoticed, by enabling a message, should this ever
1589 occur. This will allow people with obscure setups to know when things
1590 are going wrong, so that they might contact developers about fixing
1591 it.
1592
eecabf56
TT
1593 Unfortunately, on some models of some architectures getting
1594 a fully seeded CRNG is extremely difficult, and so this can
1595 result in dmesg getting spammed for a surprisingly long
1596 time. This is really bad from a security perspective, and
1597 so architecture maintainers really need to do what they can
1598 to get the CRNG seeded sooner after the system is booted.
4c5d114e 1599 However, since users cannot do anything actionable to
cc1e127b 1600 address this, by default this option is disabled.
eecabf56
TT
1601
1602 Say Y here if you want to receive warnings for all uses of
1603 unseeded randomness. This will be of use primarily for
4c5d114e 1604 those developers interested in improving the security of
eecabf56
TT
1605 Linux kernels running on their architecture (or
1606 subarchitecture).
d06bfd19 1607
1da177e4
LT
1608config DEBUG_KOBJECT
1609 bool "kobject debugging"
1610 depends on DEBUG_KERNEL
1611 help
1612 If you say Y here, some extra kobject debugging messages will be sent
aca52c39 1613 to the syslog.
1da177e4 1614
c817a67e
RK
1615config DEBUG_KOBJECT_RELEASE
1616 bool "kobject release debugging"
2a999aa0 1617 depends on DEBUG_OBJECTS_TIMERS
c817a67e
RK
1618 help
1619 kobjects are reference counted objects. This means that their
1620 last reference count put is not predictable, and the kobject can
b6c69474 1621 live on past the point at which a driver decides to drop its
c817a67e
RK
1622 initial reference to the kobject gained on allocation. An
1623 example of this would be a struct device which has just been
1624 unregistered.
1625
1626 However, some buggy drivers assume that after such an operation,
1627 the memory backing the kobject can be immediately freed. This
1628 goes completely against the principles of a refcounted object.
1629
1630 If you say Y here, the kernel will delay the release of kobjects
1631 on the last reference count to improve the visibility of this
1632 kind of kobject release bug.
1633
9b2a60c4
CM
1634config HAVE_DEBUG_BUGVERBOSE
1635 bool
1636
3be5cbcd 1637menu "Debug kernel data structures"
1da177e4 1638
199a9afc
DJ
1639config DEBUG_LIST
1640 bool "Debug linked list manipulation"
4520bcb2 1641 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
199a9afc
DJ
1642 help
1643 Enable this to turn on extended checks in the linked-list
1644 walking routines.
1645
1646 If unsure, say N.
1647
8e18faea 1648config DEBUG_PLIST
b8cfff68
DS
1649 bool "Debug priority linked list manipulation"
1650 depends on DEBUG_KERNEL
1651 help
1652 Enable this to turn on extended checks in the priority-ordered
1653 linked-list (plist) walking routines. This checks the entire
1654 list multiple times during each manipulation.
1655
1656 If unsure, say N.
1657
d6ec0842
JA
1658config DEBUG_SG
1659 bool "Debug SG table operations"
1660 depends on DEBUG_KERNEL
1661 help
1662 Enable this to turn on checks on scatter-gather tables. This can
1663 help find problems with drivers that do not properly initialize
1664 their sg tables.
1665
1666 If unsure, say N.
1667
1b2439db
AV
1668config DEBUG_NOTIFIERS
1669 bool "Debug notifier call chains"
1670 depends on DEBUG_KERNEL
1671 help
1672 Enable this to turn on sanity checking for notifier call chains.
1673 This is most useful for kernel developers to make sure that
1674 modules properly unregister themselves from notifier chains.
1675 This is a relatively cheap check but if you care about maximum
1676 performance, say N.
1677
3be5cbcd
CD
1678config BUG_ON_DATA_CORRUPTION
1679 bool "Trigger a BUG when data corruption is detected"
1680 select DEBUG_LIST
1681 help
1682 Select this option if the kernel should BUG when it encounters
1683 data corruption in kernel memory structures when they get checked
1684 for validity.
1685
1686 If unsure, say N.
1687
54a611b6
LH
1688config DEBUG_MAPLE_TREE
1689 bool "Debug maple trees"
1690 depends on DEBUG_KERNEL
1691 help
1692 Enable maple tree debugging information and extra validations.
1693
1694 If unsure, say N.
1695
3be5cbcd
CD
1696endmenu
1697
e0e81739
DH
1698config DEBUG_CREDENTIALS
1699 bool "Debug credential management"
1700 depends on DEBUG_KERNEL
1701 help
1702 Enable this to turn on some debug checking for credential
1703 management. The additional code keeps track of the number of
1704 pointers from task_structs to any given cred struct, and checks to
1705 see that this number never exceeds the usage count of the cred
1706 struct.
1707
1708 Furthermore, if SELinux is enabled, this also checks that the
1709 security pointer in the cred struct is never seen to be invalid.
1710
1711 If unsure, say N.
1712
43a0a2a7 1713source "kernel/rcu/Kconfig.debug"
2f03e3ca 1714
f303fccb
TH
1715config DEBUG_WQ_FORCE_RR_CPU
1716 bool "Force round-robin CPU selection for unbound work items"
1717 depends on DEBUG_KERNEL
1718 default n
1719 help
1720 Workqueue used to implicitly guarantee that work items queued
1721 without explicit CPU specified are put on the local CPU. This
1722 guarantee is no longer true and while local CPU is still
1723 preferred work items may be put on foreign CPUs. Kernel
1724 parameter "workqueue.debug_force_rr_cpu" is added to force
1725 round-robin CPU selection to flush out usages which depend on the
1726 now broken guarantee. This config option enables the debug
1727 feature by default. When enabled, memory and cache locality will
1728 be impacted.
1729
757c989b
TG
1730config CPU_HOTPLUG_STATE_CONTROL
1731 bool "Enable CPU hotplug state control"
1732 depends on DEBUG_KERNEL
1733 depends on HOTPLUG_CPU
1734 default n
1735 help
1736 Allows to write steps between "offline" and "online" to the CPUs
1737 sysfs target file so states can be stepped granular. This is a debug
1738 option for now as the hotplug machinery cannot be stopped and
1739 restarted at arbitrary points yet.
1740
1741 Say N if your are unsure.
1742
09a74952
CD
1743config LATENCYTOP
1744 bool "Latency measuring infrastructure"
1745 depends on DEBUG_KERNEL
1746 depends on STACKTRACE_SUPPORT
1747 depends on PROC_FS
7d37cb2c 1748 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
09a74952
CD
1749 select KALLSYMS
1750 select KALLSYMS_ALL
1751 select STACKTRACE
1752 select SCHEDSTATS
09a74952
CD
1753 help
1754 Enable this option if you want to use the LatencyTOP tool
1755 to find out which userspace is blocking on what kernel operations.
1756
6ab42860
TH
1757config DEBUG_CGROUP_REF
1758 bool "Disable inlining of cgroup css reference count functions"
1759 depends on DEBUG_KERNEL
1760 depends on CGROUPS
1761 depends on KPROBES
1762 default n
1763 help
1764 Force cgroup css reference count functions to not be inlined so
1765 that they can be kprobed for debugging.
1766
09a74952
CD
1767source "kernel/trace/Kconfig"
1768
1769config PROVIDE_OHCI1394_DMA_INIT
1770 bool "Remote debugging over FireWire early on boot"
1771 depends on PCI && X86
1772 help
1773 If you want to debug problems which hang or crash the kernel early
1774 on boot and the crashing machine has a FireWire port, you can use
1775 this feature to remotely access the memory of the crashed machine
1776 over FireWire. This employs remote DMA as part of the OHCI1394
1777 specification which is now the standard for FireWire controllers.
1778
1779 With remote DMA, you can monitor the printk buffer remotely using
1780 firescope and access all memory below 4GB using fireproxy from gdb.
1781 Even controlling a kernel debugger is possible using remote DMA.
1782
1783 Usage:
1784
1785 If ohci1394_dma=early is used as boot parameter, it will initialize
1786 all OHCI1394 controllers which are found in the PCI config space.
1787
1788 As all changes to the FireWire bus such as enabling and disabling
1789 devices cause a bus reset and thereby disable remote DMA for all
1790 devices, be sure to have the cable plugged and FireWire enabled on
1791 the debugging host before booting the debug target for debugging.
1792
1793 This code (~1k) is freed after boot. By then, the firewire stack
1794 in charge of the OHCI-1394 controllers should be used instead.
1795
a74e2a22 1796 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
09a74952 1797
045f6d79
CD
1798source "samples/Kconfig"
1799
1800config ARCH_HAS_DEVMEM_IS_ALLOWED
1801 bool
1802
1803config STRICT_DEVMEM
1804 bool "Filter access to /dev/mem"
1805 depends on MMU && DEVMEM
527701ed 1806 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
045f6d79
CD
1807 default y if PPC || X86 || ARM64
1808 help
1809 If this option is disabled, you allow userspace (root) access to all
1810 of memory, including kernel and userspace memory. Accidental
1811 access to this is obviously disastrous, but specific access can
1812 be used by people debugging the kernel. Note that with PAT support
1813 enabled, even in this case there are restrictions on /dev/mem
1814 use due to the cache aliasing requirements.
1815
1816 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1817 file only allows userspace access to PCI space and the BIOS code and
1818 data regions. This is sufficient for dosemu and X and all common
1819 users of /dev/mem.
1820
1821 If in doubt, say Y.
1822
1823config IO_STRICT_DEVMEM
1824 bool "Filter I/O access to /dev/mem"
1825 depends on STRICT_DEVMEM
1826 help
1827 If this option is disabled, you allow userspace (root) access to all
1828 io-memory regardless of whether a driver is actively using that
1829 range. Accidental access to this is obviously disastrous, but
1830 specific access can be used by people debugging kernel drivers.
1831
1832 If this option is switched on, the /dev/mem file only allows
1833 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1834 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1835 if the driver using a given range cannot be disabled.
1836
1837 If in doubt, say Y.
1838
1839menu "$(SRCARCH) Debugging"
1840
1841source "arch/$(SRCARCH)/Kconfig.debug"
1842
1843endmenu
1844
1845menu "Kernel Testing and Coverage"
1846
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CD
1847source "lib/kunit/Kconfig"
1848
8d438288
AM
1849config NOTIFIER_ERROR_INJECTION
1850 tristate "Notifier error injection"
1851 depends on DEBUG_KERNEL
1852 select DEBUG_FS
1853 help
e41e85cc 1854 This option provides the ability to inject artificial errors to
8d438288
AM
1855 specified notifier chain callbacks. It is useful to test the error
1856 handling of notifier call chain failures.
1857
1858 Say N if unsure.
1859
048b9c35
AM
1860config PM_NOTIFIER_ERROR_INJECT
1861 tristate "PM notifier error injection module"
1862 depends on PM && NOTIFIER_ERROR_INJECTION
1863 default m if PM_DEBUG
1864 help
e41e85cc 1865 This option provides the ability to inject artificial errors to
048b9c35
AM
1866 PM notifier chain callbacks. It is controlled through debugfs
1867 interface /sys/kernel/debug/notifier-error-inject/pm
1868
1869 If the notifier call chain should be failed with some events
1870 notified, write the error code to "actions/<notifier event>/error".
1871
1872 Example: Inject PM suspend error (-12 = -ENOMEM)
1873
1874 # cd /sys/kernel/debug/notifier-error-inject/pm/
1875 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1876 # echo mem > /sys/power/state
1877 bash: echo: write error: Cannot allocate memory
1878
1879 To compile this code as a module, choose M here: the module will
1880 be called pm-notifier-error-inject.
1881
1882 If unsure, say N.
1883
d526e85f
BH
1884config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1885 tristate "OF reconfig notifier error injection module"
1886 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dd 1887 help
e41e85cc 1888 This option provides the ability to inject artificial errors to
d526e85f 1889 OF reconfig notifier chain callbacks. It is controlled
08dfb4dd 1890 through debugfs interface under
d526e85f 1891 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
08dfb4dd
AM
1892
1893 If the notifier call chain should be failed with some events
1894 notified, write the error code to "actions/<notifier event>/error".
1895
1896 To compile this code as a module, choose M here: the module will
e12a95f4 1897 be called of-reconfig-notifier-error-inject.
08dfb4dd
AM
1898
1899 If unsure, say N.
1900
02fff96a
NA
1901config NETDEV_NOTIFIER_ERROR_INJECT
1902 tristate "Netdev notifier error injection module"
1903 depends on NET && NOTIFIER_ERROR_INJECTION
1904 help
1905 This option provides the ability to inject artificial errors to
1906 netdevice notifier chain callbacks. It is controlled through debugfs
1907 interface /sys/kernel/debug/notifier-error-inject/netdev
1908
1909 If the notifier call chain should be failed with some events
1910 notified, write the error code to "actions/<notifier event>/error".
1911
1912 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1913
1914 # cd /sys/kernel/debug/notifier-error-inject/netdev
1915 # echo -22 > actions/NETDEV_CHANGEMTU/error
1916 # ip link set eth0 mtu 1024
1917 RTNETLINK answers: Invalid argument
1918
1919 To compile this code as a module, choose M here: the module will
1920 be called netdev-notifier-error-inject.
1921
1922 If unsure, say N.
1923
f1b4bd06 1924config FUNCTION_ERROR_INJECTION
a4412fdd 1925 bool "Fault-injections of functions"
f1b4bd06 1926 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
a4412fdd
SRG
1927 help
1928 Add fault injections into various functions that are annotated with
1929 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
ca0f2cfc 1930 value of these functions. This is useful to test error paths of code.
a4412fdd
SRG
1931
1932 If unsure, say N
f1b4bd06 1933
6ff1cb35 1934config FAULT_INJECTION
1ab8509a
AM
1935 bool "Fault-injection framework"
1936 depends on DEBUG_KERNEL
329409ae
AM
1937 help
1938 Provide fault-injection framework.
1939 For more details, see Documentation/fault-injection/.
6ff1cb35 1940
8a8b6502 1941config FAILSLAB
1ab8509a
AM
1942 bool "Fault-injection capability for kmalloc"
1943 depends on FAULT_INJECTION
773ff60e 1944 depends on SLAB || SLUB
8a8b6502 1945 help
1ab8509a 1946 Provide fault-injection capability for kmalloc.
8a8b6502 1947
933e312e 1948config FAIL_PAGE_ALLOC
29b46fa3 1949 bool "Fault-injection capability for alloc_pages()"
1ab8509a 1950 depends on FAULT_INJECTION
933e312e 1951 help
1ab8509a 1952 Provide fault-injection capability for alloc_pages().
933e312e 1953
2c739ced
AL
1954config FAULT_INJECTION_USERCOPY
1955 bool "Fault injection capability for usercopy functions"
1956 depends on FAULT_INJECTION
1957 help
1958 Provides fault-injection capability to inject failures
1959 in usercopy functions (copy_from_user(), get_user(), ...).
1960
c17bb495 1961config FAIL_MAKE_REQUEST
86327d19 1962 bool "Fault-injection capability for disk IO"
581d4e28 1963 depends on FAULT_INJECTION && BLOCK
c17bb495 1964 help
1ab8509a 1965 Provide fault-injection capability for disk IO.
c17bb495 1966
581d4e28 1967config FAIL_IO_TIMEOUT
f4d01439 1968 bool "Fault-injection capability for faking disk interrupts"
581d4e28
JA
1969 depends on FAULT_INJECTION && BLOCK
1970 help
1971 Provide fault-injection capability on end IO handling. This
1972 will make the block layer "forget" an interrupt as configured,
1973 thus exercising the error handling.
1974
1975 Only works with drivers that use the generic timeout handling,
9dbbc3b9 1976 for others it won't do anything.
581d4e28 1977
ab51fbab
DB
1978config FAIL_FUTEX
1979 bool "Fault-injection capability for futexes"
1980 select DEBUG_FS
1981 depends on FAULT_INJECTION && FUTEX
1982 help
1983 Provide fault-injection capability for futexes.
1984
f1b4bd06
MP
1985config FAULT_INJECTION_DEBUG_FS
1986 bool "Debugfs entries for fault-injection capabilities"
1987 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1988 help
1989 Enable configuration of fault-injection capabilities via debugfs.
1990
4b1a29a7
MH
1991config FAIL_FUNCTION
1992 bool "Fault-injection capability for functions"
1993 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1994 help
1995 Provide function-based fault-injection capability.
1996 This will allow you to override a specific function with a return
1997 with given return value. As a result, function caller will see
1998 an error value and have to handle it. This is useful to test the
1999 error handling in various subsystems.
2000
f1b4bd06
MP
2001config FAIL_MMC_REQUEST
2002 bool "Fault-injection capability for MMC IO"
2003 depends on FAULT_INJECTION_DEBUG_FS && MMC
6ff1cb35 2004 help
f1b4bd06
MP
2005 Provide fault-injection capability for MMC IO.
2006 This will make the mmc core return data errors. This is
2007 useful to test the error handling in the mmc block device
2008 and to test how the mmc host driver handles retries from
2009 the block device.
1df49008 2010
c782af25
CL
2011config FAIL_SUNRPC
2012 bool "Fault-injection capability for SunRPC"
2013 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2014 help
2015 Provide fault-injection capability for SunRPC and
2016 its consumers.
2017
1df49008
AM
2018config FAULT_INJECTION_STACKTRACE_FILTER
2019 bool "stacktrace filter for fault-injection capabilities"
2020 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2021 select STACKTRACE
7d37cb2c 2022 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1df49008
AM
2023 help
2024 Provide stacktrace filter for fault-injection capabilities
267c4025 2025
09a74952
CD
2026config ARCH_HAS_KCOV
2027 bool
cc3fa840 2028 help
09a74952
CD
2029 An architecture should select this when it can successfully
2030 build and run with CONFIG_KCOV. This typically requires
2031 disabling instrumentation for some early boot code.
cc3fa840 2032
09a74952
CD
2033config CC_HAS_SANCOV_TRACE_PC
2034 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
cc3fa840 2035
cc3fa840 2036
09a74952
CD
2037config KCOV
2038 bool "Code coverage for fuzzing"
2039 depends on ARCH_HAS_KCOV
2040 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
22102f45 2041 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
bece04b5 2042 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
09a74952
CD
2043 select DEBUG_FS
2044 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
22102f45 2045 select OBJTOOL if HAVE_NOINSTR_HACK
09a74952
CD
2046 help
2047 KCOV exposes kernel code coverage information in a form suitable
2048 for coverage-guided fuzzing (randomized testing).
cc3fa840 2049
09a74952
CD
2050 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2051 different machines and across reboots. If you need stable PC values,
2052 disable RANDOMIZE_BASE.
cc3fa840 2053
09a74952 2054 For more details, see Documentation/dev-tools/kcov.rst.
cc3fa840 2055
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CD
2056config KCOV_ENABLE_COMPARISONS
2057 bool "Enable comparison operands collection by KCOV"
2058 depends on KCOV
2059 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2060 help
2061 KCOV also exposes operands of every comparison in the instrumented
2062 code along with operand sizes and PCs of the comparison instructions.
2063 These operands can be used by fuzzing engines to improve the quality
2064 of fuzzing coverage.
cc3fa840 2065
09a74952
CD
2066config KCOV_INSTRUMENT_ALL
2067 bool "Instrument all code by default"
2068 depends on KCOV
2069 default y
2070 help
2071 If you are doing generic system call fuzzing (like e.g. syzkaller),
2072 then you will want to instrument the whole kernel and you should
2073 say y here. If you are doing more targeted fuzzing (like e.g.
2074 filesystem fuzzing with AFL) then you will want to enable coverage
2075 for more specific subsets of files, and should say n here.
84bc809e 2076
5ff3b30a
AK
2077config KCOV_IRQ_AREA_SIZE
2078 hex "Size of interrupt coverage collection area in words"
2079 depends on KCOV
2080 default 0x40000
2081 help
2082 KCOV uses preallocated per-cpu areas to collect coverage from
2083 soft interrupts. This specifies the size of those areas in the
2084 number of unsigned long words.
2085
d3deafaa
VL
2086menuconfig RUNTIME_TESTING_MENU
2087 bool "Runtime Testing"
908009e8 2088 def_bool y
d3deafaa
VL
2089
2090if RUNTIME_TESTING_MENU
881c5149
DH
2091
2092config LKDTM
2093 tristate "Linux Kernel Dump Test Tool Module"
2094 depends on DEBUG_FS
881c5149
DH
2095 help
2096 This module enables testing of the different dumping mechanisms by
2097 inducing system failures at predefined crash points.
2098 If you don't need it: say N
2099 Choose M here to compile this code as a module. The module will be
2100 called lkdtm.
2101
2102 Documentation on how to use the module can be found in
10ffebbe 2103 Documentation/fault-injection/provoke-crashes.rst
881c5149 2104
d3c0ca49
SV
2105config CPUMASK_KUNIT_TEST
2106 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
c41e8866
SV
2107 depends on KUNIT
2108 default KUNIT_ALL_TESTS
2109 help
2110 Enable to turn on cpumask tests, running at boot or module load time.
2111
d3c0ca49
SV
2112 For more information on KUnit and unit tests in general, please refer
2113 to the KUnit documentation in Documentation/dev-tools/kunit/.
2114
c41e8866
SV
2115 If unsure, say N.
2116
881c5149 2117config TEST_LIST_SORT
ebd09577
DL
2118 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2119 depends on KUNIT
2120 default KUNIT_ALL_TESTS
881c5149
DH
2121 help
2122 Enable this to turn on 'list_sort()' function test. This test is
e327fd7c
GU
2123 executed only once during system boot (so affects only boot time),
2124 or at module load time.
881c5149
DH
2125
2126 If unsure, say N.
2127
6e24628d
IR
2128config TEST_MIN_HEAP
2129 tristate "Min heap test"
2130 depends on DEBUG_KERNEL || m
2131 help
2132 Enable this to turn on min heap function tests. This test is
2133 executed only once during system boot (so affects only boot time),
2134 or at module load time.
2135
2136 If unsure, say N.
2137
c5adae95 2138config TEST_SORT
36f33b56
DL
2139 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2140 depends on KUNIT
2141 default KUNIT_ALL_TESTS
c5adae95 2142 help
5c4e6798
GU
2143 This option enables the self-test function of 'sort()' at boot,
2144 or at module load time.
c5adae95
KF
2145
2146 If unsure, say N.
2147
5086ea4b
MR
2148config TEST_DIV64
2149 tristate "64bit/32bit division and modulo test"
2150 depends on DEBUG_KERNEL || m
2151 help
2152 Enable this to turn on 'do_div()' function test. This test is
2153 executed only once during system boot (so affects only boot time),
2154 or at module load time.
2155
2156 If unsure, say N.
2157
881c5149 2158config KPROBES_SANITY_TEST
dcbb2ee2 2159 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
881c5149
DH
2160 depends on DEBUG_KERNEL
2161 depends on KPROBES
e44e81c5 2162 depends on KUNIT
de3db3f8 2163 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
dcbb2ee2 2164 default KUNIT_ALL_TESTS
881c5149
DH
2165 help
2166 This option provides for testing basic kprobes functionality on
5a6cf77f 2167 boot. Samples of kprobe and kretprobe are inserted and
881c5149
DH
2168 verified for functionality.
2169
2170 Say N if you are unsure.
2171
f4616fab
MH
2172config FPROBE_SANITY_TEST
2173 bool "Self test for fprobe"
2174 depends on DEBUG_KERNEL
2175 depends on FPROBE
2176 depends on KUNIT=y
2177 help
2178 This option will enable testing the fprobe when the system boot.
2179 A series of tests are made to verify that the fprobe is functioning
2180 properly.
2181
2182 Say N if you are unsure.
2183
881c5149
DH
2184config BACKTRACE_SELF_TEST
2185 tristate "Self test for the backtrace code"
2186 depends on DEBUG_KERNEL
881c5149
DH
2187 help
2188 This option provides a kernel module that can be used to test
2189 the kernel stack backtrace code. This option is not useful
2190 for distributions or general kernels, but only for kernel
2191 developers working on architecture code.
2192
2193 Note that if you want to also test saved backtraces, you will
2194 have to enable STACKTRACE as well.
2195
2196 Say N if you are unsure.
2197
914a7b50
ED
2198config TEST_REF_TRACKER
2199 tristate "Self test for reference tracker"
2200 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2201 select REF_TRACKER
2202 help
2203 This option provides a kernel module performing tests
2204 using reference tracker infrastructure.
2205
2206 Say N if you are unsure.
2207
910a742d
ML
2208config RBTREE_TEST
2209 tristate "Red-Black tree test"
7c993e11 2210 depends on DEBUG_KERNEL
910a742d
ML
2211 help
2212 A benchmark measuring the performance of the rbtree library.
2213 Also includes rbtree invariant checks.
2214
4b4f3acc
FB
2215config REED_SOLOMON_TEST
2216 tristate "Reed-Solomon library test"
2217 depends on DEBUG_KERNEL || m
2218 select REED_SOLOMON
2219 select REED_SOLOMON_ENC16
2220 select REED_SOLOMON_DEC16
2221 help
2222 This option enables the self-test function of rslib at boot,
2223 or at module load time.
2224
2225 If unsure, say N.
2226
fff3fd8a
ML
2227config INTERVAL_TREE_TEST
2228 tristate "Interval tree test"
0f789b67 2229 depends on DEBUG_KERNEL
a88cc108 2230 select INTERVAL_TREE
fff3fd8a
ML
2231 help
2232 A benchmark measuring the performance of the interval tree library
2233
623fd807
GT
2234config PERCPU_TEST
2235 tristate "Per cpu operations test"
2236 depends on m && DEBUG_KERNEL
2237 help
2238 Enable this option to build test module which validates per-cpu
2239 operations.
2240
2241 If unsure, say N.
2242
881c5149 2243config ATOMIC64_SELFTEST
55ded955 2244 tristate "Perform an atomic64_t self-test"
881c5149 2245 help
55ded955
GU
2246 Enable this option to test the atomic64_t functions at boot or
2247 at module load time.
881c5149
DH
2248
2249 If unsure, say N.
2250
2251config ASYNC_RAID6_TEST
2252 tristate "Self test for hardware accelerated raid6 recovery"
2253 depends on ASYNC_RAID6_RECOV
2254 select ASYNC_MEMCPY
a7f7f624 2255 help
881c5149
DH
2256 This is a one-shot self test that permutes through the
2257 recovery of all the possible two disk failure scenarios for a
2258 N-disk array. Recovery is performed with the asynchronous
2259 raid6 recovery routines, and will optionally use an offload
2260 engine if one is available.
2261
2262 If unsure, say N.
2263
64d1d77a
AS
2264config TEST_HEXDUMP
2265 tristate "Test functions located in the hexdump module at runtime"
2266
b2ff70a0
MC
2267config STRING_SELFTEST
2268 tristate "Test string functions at runtime"
2269
881c5149
DH
2270config TEST_STRING_HELPERS
2271 tristate "Test functions located in the string_helpers module at runtime"
2272
2273config TEST_KSTRTOX
2274 tristate "Test kstrto*() family of functions at runtime"
2275
707cc728
RV
2276config TEST_PRINTF
2277 tristate "Test printf() family of functions at runtime"
2278
50f530e1
RF
2279config TEST_SCANF
2280 tristate "Test scanf() family of functions at runtime"
2281
5fd003f5
DD
2282config TEST_BITMAP
2283 tristate "Test bitmap_*() family of functions at runtime"
5fd003f5
DD
2284 help
2285 Enable this option to test the bitmap functions at boot.
2286
2287 If unsure, say N.
2288
cfaff0e5
AS
2289config TEST_UUID
2290 tristate "Test functions located in the uuid module at runtime"
2291
ad3d6c72
MW
2292config TEST_XARRAY
2293 tristate "Test the XArray code at runtime"
2294
120b1162 2295config TEST_MAPLE_TREE
845aad0a 2296 depends on DEBUG_KERNEL
120b1162
LH
2297 select DEBUG_MAPLE_TREE
2298 tristate "Test the Maple Tree code at runtime"
2299
7e1e7763 2300config TEST_RHASHTABLE
9d6dbe1b 2301 tristate "Perform selftest on resizable hash table"
7e1e7763
TG
2302 help
2303 Enable this option to test the rhashtable functions at boot.
2304
2305 If unsure, say N.
2306
8ab8ba38
MW
2307config TEST_IDA
2308 tristate "Perform selftest on IDA functions"
2309
44091d29
JP
2310config TEST_PARMAN
2311 tristate "Perform selftest on priority array manager"
44091d29
JP
2312 depends on PARMAN
2313 help
2314 Enable this option to test priority array manager on boot
2315 (or module load).
2316
2317 If unsure, say N.
2318
6aed82de
DL
2319config TEST_IRQ_TIMINGS
2320 bool "IRQ timings selftest"
2321 depends on IRQ_TIMINGS
2322 help
2323 Enable this option to test the irq timings code on boot.
2324
2325 If unsure, say N.
2326
8a6f0b47 2327config TEST_LKM
93e9ef83 2328 tristate "Test module loading with 'hello world' module"
93e9ef83
KC
2329 depends on m
2330 help
2331 This builds the "test_module" module that emits "Hello, world"
2332 on printk when loaded. It is designed to be used for basic
2333 evaluation of the module loading subsystem (for example when
2334 validating module verification). It lacks any extra dependencies,
2335 and will not normally be loaded by the system unless explicitly
2336 requested by name.
2337
2338 If unsure, say N.
2339
c348c163 2340config TEST_BITOPS
6af132f3 2341 tristate "Test module for compilation of bitops operations"
c348c163
JB
2342 depends on m
2343 help
2344 This builds the "test_bitops" module that is much like the
2345 TEST_LKM module except that it does a basic exercise of the
6af132f3
WY
2346 set/clear_bit macros and get_count_order/long to make sure there are
2347 no compiler warnings from C=1 sparse checker or -Wextra
2348 compilations. It has no dependencies and doesn't run or load unless
2349 explicitly requested by name. for example: modprobe test_bitops.
c348c163
JB
2350
2351 If unsure, say N.
2352
3f21a6b7
URS
2353config TEST_VMALLOC
2354 tristate "Test module for stress/performance analysis of vmalloc allocator"
2355 default n
2356 depends on MMU
2357 depends on m
2358 help
2359 This builds the "test_vmalloc" module that should be used for
2360 stress and performance analysis. So, any new change for vmalloc
2361 subsystem can be evaluated from performance and stability point
2362 of view.
2363
2364 If unsure, say N.
2365
3e2a4c18
KC
2366config TEST_USER_COPY
2367 tristate "Test user/kernel boundary protections"
3e2a4c18
KC
2368 depends on m
2369 help
2370 This builds the "test_user_copy" module that runs sanity checks
2371 on the copy_to/from_user infrastructure, making sure basic
2372 user/kernel boundary testing is working. If it fails to load,
2373 a regression has been detected in the user/kernel memory boundary
2374 protections.
2375
2376 If unsure, say N.
2377
64a8946b
AS
2378config TEST_BPF
2379 tristate "Test BPF filter functionality"
98920ba6 2380 depends on m && NET
64a8946b
AS
2381 help
2382 This builds the "test_bpf" module that runs various test vectors
2383 against the BPF interpreter or BPF JIT compiler depending on the
2384 current setting. This is in particular useful for BPF JIT compiler
2385 development, but also to run regression tests against changes in
3c731eba
AS
2386 the interpreter code. It also enables test stubs for eBPF maps and
2387 verifier used by user space verifier testsuite.
64a8946b
AS
2388
2389 If unsure, say N.
2390
509e56b3
MB
2391config TEST_BLACKHOLE_DEV
2392 tristate "Test blackhole netdev functionality"
2393 depends on m && NET
2394 help
2395 This builds the "test_blackhole_dev" module that validates the
2396 data path through this blackhole netdev.
2397
2398 If unsure, say N.
2399
dceeb3e7 2400config FIND_BIT_BENCHMARK
4441fca0 2401 tristate "Test find_bit functions"
4441fca0
YN
2402 help
2403 This builds the "test_find_bit" module that measure find_*_bit()
2404 functions performance.
2405
2406 If unsure, say N.
2407
0a8adf58
KC
2408config TEST_FIRMWARE
2409 tristate "Test firmware loading via userspace interface"
0a8adf58
KC
2410 depends on FW_LOADER
2411 help
2412 This builds the "test_firmware" module that creates a userspace
2413 interface for testing firmware loading. This can be used to
2414 control the triggering of firmware loading without needing an
2415 actual firmware-using device. The contents can be rechecked by
2416 userspace.
2417
2418 If unsure, say N.
2419
9308f2f9
LR
2420config TEST_SYSCTL
2421 tristate "sysctl test driver"
9308f2f9
LR
2422 depends on PROC_SYSCTL
2423 help
2424 This builds the "test_sysctl" module. This driver enables to test the
2425 proc sysctl interfaces available to drivers safely without affecting
2426 production knobs which might alter system functionality.
2427
2428 If unsure, say N.
2429
d2585f51 2430config BITFIELD_KUNIT
dcbb2ee2 2431 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
d2585f51 2432 depends on KUNIT
dcbb2ee2 2433 default KUNIT_ALL_TESTS
d2585f51
VMI
2434 help
2435 Enable this option to test the bitfield functions at boot.
2436
2437 KUnit tests run during boot and output the results to the debug log
2438 in TAP format (http://testanything.org/). Only useful for kernel devs
2439 running the KUnit test harness, and not intended for inclusion into a
2440 production build.
2441
2442 For more information on KUnit and unit tests in general please refer
2443 to the KUnit documentation in Documentation/dev-tools/kunit/.
2444
2445 If unsure, say N.
2446
0acc968f
IB
2447config HASH_KUNIT_TEST
2448 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2449 depends on KUNIT
2450 default KUNIT_ALL_TESTS
2451 help
2452 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2453 integer (<linux/hash.h>) hash functions on boot.
2454
2455 KUnit tests run during boot and output the results to the debug log
2456 in TAP format (https://testanything.org/). Only useful for kernel devs
2457 running the KUnit test harness, and not intended for inclusion into a
2458 production build.
2459
2460 For more information on KUnit and unit tests in general please refer
2461 to the KUnit documentation in Documentation/dev-tools/kunit/.
2462
2463 This is intended to help people writing architecture-specific
2464 optimized versions. If unsure, say N.
2465
5df38ca6 2466config RESOURCE_KUNIT_TEST
dcbb2ee2 2467 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
5df38ca6 2468 depends on KUNIT
dcbb2ee2 2469 default KUNIT_ALL_TESTS
5df38ca6
AS
2470 help
2471 This builds the resource API unit test.
2472 Tests the logic of API provided by resource.c and ioport.h.
2473 For more information on KUnit and unit tests in general please refer
2474 to the KUnit documentation in Documentation/dev-tools/kunit/.
2475
2476 If unsure, say N.
2477
2cb80dbb 2478config SYSCTL_KUNIT_TEST
5f215aab 2479 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2cb80dbb 2480 depends on KUNIT
5f215aab 2481 default KUNIT_ALL_TESTS
2cb80dbb
IZ
2482 help
2483 This builds the proc sysctl unit test, which runs on boot.
2484 Tests the API contract and implementation correctness of sysctl.
2485 For more information on KUnit and unit tests in general please refer
2486 to the KUnit documentation in Documentation/dev-tools/kunit/.
2487
2488 If unsure, say N.
2489
ea2dd7c0 2490config LIST_KUNIT_TEST
5f215aab 2491 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
ea2dd7c0 2492 depends on KUNIT
5f215aab 2493 default KUNIT_ALL_TESTS
ea2dd7c0
DG
2494 help
2495 This builds the linked list KUnit test suite.
2496 It tests that the API and basic functionality of the list_head type
2497 and associated macros.
2498
2499 KUnit tests run during boot and output the results to the debug log
d89775fc 2500 in TAP format (https://testanything.org/). Only useful for kernel devs
ea2dd7c0
DG
2501 running the KUnit test harness, and not intended for inclusion into a
2502 production build.
2503
2504 For more information on KUnit and unit tests in general please refer
2505 to the KUnit documentation in Documentation/dev-tools/kunit/.
2506
2507 If unsure, say N.
2508
33d599f0
MV
2509config LINEAR_RANGES_TEST
2510 tristate "KUnit test for linear_ranges"
2511 depends on KUNIT
2512 select LINEAR_RANGES
2513 help
2514 This builds the linear_ranges unit test, which runs on boot.
2515 Tests the linear_ranges logic correctness.
2516 For more information on KUnit and unit tests in general please refer
7546861a
AS
2517 to the KUnit documentation in Documentation/dev-tools/kunit/.
2518
2519 If unsure, say N.
2520
2521config CMDLINE_KUNIT_TEST
dcbb2ee2 2522 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
7546861a 2523 depends on KUNIT
dcbb2ee2 2524 default KUNIT_ALL_TESTS
7546861a
AS
2525 help
2526 This builds the cmdline API unit test.
2527 Tests the logic of API provided by cmdline.c.
2528 For more information on KUnit and unit tests in general please refer
33d599f0
MV
2529 to the KUnit documentation in Documentation/dev-tools/kunit/.
2530
2531 If unsure, say N.
2532
6d511020 2533config BITS_TEST
dcbb2ee2 2534 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
6d511020 2535 depends on KUNIT
dcbb2ee2 2536 default KUNIT_ALL_TESTS
6d511020
RF
2537 help
2538 This builds the bits unit test.
2539 Tests the logic of macros defined in bits.h.
2540 For more information on KUnit and unit tests in general please refer
2541 to the KUnit documentation in Documentation/dev-tools/kunit/.
2542
2543 If unsure, say N.
2544
1f9f78b1
OG
2545config SLUB_KUNIT_TEST
2546 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2547 depends on SLUB_DEBUG && KUNIT
2548 default KUNIT_ALL_TESTS
2549 help
2550 This builds SLUB allocator unit test.
2551 Tests SLUB cache debugging functionality.
2552 For more information on KUnit and unit tests in general please refer
2553 to the KUnit documentation in Documentation/dev-tools/kunit/.
2554
2555 If unsure, say N.
2556
b6c75c4a
TP
2557config RATIONAL_KUNIT_TEST
2558 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
8ba739ed 2559 depends on KUNIT && RATIONAL
b6c75c4a
TP
2560 default KUNIT_ALL_TESTS
2561 help
2562 This builds the rational math unit test.
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 If unsure, say N.
2567
bb95ebbe
KC
2568config MEMCPY_KUNIT_TEST
2569 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2570 depends on KUNIT
2571 default KUNIT_ALL_TESTS
2572 help
2573 Builds unit tests for memcpy(), memmove(), and memset() functions.
2574 For more information on KUnit and unit tests in general please refer
2575 to the KUnit documentation in Documentation/dev-tools/kunit/.
2576
2577 If unsure, say N.
2578
4acf1de3
KC
2579config MEMCPY_SLOW_KUNIT_TEST
2580 bool "Include exhaustive memcpy tests"
2581 depends on MEMCPY_KUNIT_TEST
2582 default y
2583 help
2584 Some memcpy tests are quite exhaustive in checking for overlaps
2585 and bit ranges. These can be very slow, so they are split out
2586 as a separate config, in case they need to be disabled.
2587
addbeea6
BVA
2588config IS_SIGNED_TYPE_KUNIT_TEST
2589 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2590 depends on KUNIT
2591 default KUNIT_ALL_TESTS
2592 help
2593 Builds unit tests for the is_signed_type() macro.
2594
2595 For more information on KUnit and unit tests in general please refer
2596 to the KUnit documentation in Documentation/dev-tools/kunit/.
2597
2598 If unsure, say N.
2599
617f55e2
KC
2600config OVERFLOW_KUNIT_TEST
2601 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2602 depends on KUNIT
2603 default KUNIT_ALL_TESTS
2604 help
2605 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2606 related functions.
2607
2608 For more information on KUnit and unit tests in general please refer
2609 to the KUnit documentation in Documentation/dev-tools/kunit/.
2610
2611 If unsure, say N.
2612
02788ebc
KC
2613config STACKINIT_KUNIT_TEST
2614 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2615 depends on KUNIT
2616 default KUNIT_ALL_TESTS
2617 help
2618 Test if the kernel is zero-initializing stack variables and
2619 padding. Coverage is controlled by compiler flags,
2620 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2621 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2622 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2623
875bfd52
KC
2624config FORTIFY_KUNIT_TEST
2625 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2626 depends on KUNIT && FORTIFY_SOURCE
2627 default KUNIT_ALL_TESTS
2628 help
2629 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2630 by the str*() and mem*() family of functions. For testing runtime
2631 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2632
724c299c
ME
2633config HW_BREAKPOINT_KUNIT_TEST
2634 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2635 depends on HAVE_HW_BREAKPOINT
2636 depends on KUNIT=y
2637 default KUNIT_ALL_TESTS
2638 help
2639 Tests for hw_breakpoint constraints accounting.
2640
2641 If unsure, say N.
2642
41eefc46
KC
2643config STRSCPY_KUNIT_TEST
2644 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2645 depends on KUNIT
2646 default KUNIT_ALL_TESTS
2647
fb3d88ab
KC
2648config SIPHASH_KUNIT_TEST
2649 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2650 depends on KUNIT
2651 default KUNIT_ALL_TESTS
2652 help
2653 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2654 functions on boot (or module load).
2655
2656 This is intended to help people writing architecture-specific
2657 optimized versions. If unsure, say N.
2658
e704f93a
DR
2659config TEST_UDELAY
2660 tristate "udelay test driver"
e704f93a
DR
2661 help
2662 This builds the "udelay_test" module that helps to make sure
2663 that udelay() is working properly.
2664
2665 If unsure, say N.
2666
2bf9e0ab
IM
2667config TEST_STATIC_KEYS
2668 tristate "Test static keys"
579e1acb
JB
2669 depends on m
2670 help
2bf9e0ab 2671 Test the static key interfaces.
579e1acb
JB
2672
2673 If unsure, say N.
2674
683263a5
JC
2675config TEST_DYNAMIC_DEBUG
2676 tristate "Test DYNAMIC_DEBUG"
2677 depends on DYNAMIC_DEBUG
2678 help
2679 This module registers a tracer callback to count enabled
2680 pr_debugs in a 'do_debugging' function, then alters their
2681 enablements, calls the function, and compares counts.
2682
2683 If unsure, say N.
2684
d9c6a72d
LR
2685config TEST_KMOD
2686 tristate "kmod stress tester"
d9c6a72d 2687 depends on m
d9c6a72d 2688 depends on NETDEVICES && NET_CORE && INET # for TUN
ae3d6a32 2689 depends on BLOCK
bbd2e05f 2690 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
d9c6a72d
LR
2691 select TEST_LKM
2692 select XFS_FS
2693 select TUN
2694 select BTRFS_FS
2695 help
2696 Test the kernel's module loading mechanism: kmod. kmod implements
2697 support to load modules using the Linux kernel's usermode helper.
2698 This test provides a series of tests against kmod.
2699
2700 Although technically you can either build test_kmod as a module or
2701 into the kernel we disallow building it into the kernel since
2702 it stress tests request_module() and this will very likely cause
2703 some issues by taking over precious threads available from other
2704 module load requests, ultimately this could be fatal.
2705
2706 To run tests run:
2707
2708 tools/testing/selftests/kmod/kmod.sh --help
2709
2710 If unsure, say N.
2711
e4dace36
FF
2712config TEST_DEBUG_VIRTUAL
2713 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2714 depends on DEBUG_VIRTUAL
2715 help
2716 Test the kernel's ability to detect incorrect calls to
2717 virt_to_phys() done against the non-linear part of the
2718 kernel's virtual address map.
2719
2720 If unsure, say N.
2721
ce76d938
AS
2722config TEST_MEMCAT_P
2723 tristate "Test memcat_p() helper function"
2724 help
2725 Test the memcat_p() helper for correctly merging two
2726 pointer arrays together.
2727
2728 If unsure, say N.
2729
a2818ee4
JL
2730config TEST_LIVEPATCH
2731 tristate "Test livepatching"
2732 default n
bae05437 2733 depends on DYNAMIC_DEBUG
a2818ee4
JL
2734 depends on LIVEPATCH
2735 depends on m
2736 help
2737 Test kernel livepatching features for correctness. The tests will
2738 load test modules that will be livepatched in various scenarios.
2739
2740 To run all the livepatching tests:
2741
2742 make -C tools/testing/selftests TARGETS=livepatch run_tests
2743
2744 Alternatively, individual tests may be invoked:
2745
2746 tools/testing/selftests/livepatch/test-callbacks.sh
2747 tools/testing/selftests/livepatch/test-livepatch.sh
2748 tools/testing/selftests/livepatch/test-shadow-vars.sh
2749
2750 If unsure, say N.
2751
0a020d41
JP
2752config TEST_OBJAGG
2753 tristate "Perform selftest on object aggreration manager"
2754 default n
2755 depends on OBJAGG
2756 help
2757 Enable this option to test object aggregation manager on boot
2758 (or module load).
2759
5015a300
AP
2760config TEST_MEMINIT
2761 tristate "Test heap/page initialization"
2762 help
2763 Test if the kernel is zero-initializing heap and page allocations.
2764 This can be useful to test init_on_alloc and init_on_free features.
2765
2766 If unsure, say N.
2767
b2ef9f5a
RC
2768config TEST_HMM
2769 tristate "Test HMM (Heterogeneous Memory Management)"
2770 depends on TRANSPARENT_HUGEPAGE
2771 depends on DEVICE_PRIVATE
2772 select HMM_MIRROR
2773 select MMU_NOTIFIER
2774 help
2775 This is a pseudo device driver solely for testing HMM.
2776 Say M here if you want to build the HMM test module.
2777 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2778
2779 If unsure, say N.
2780
e320d301
MWO
2781config TEST_FREE_PAGES
2782 tristate "Test freeing pages"
2783 help
2784 Test that a memory leak does not occur due to a race between
2785 freeing a block of pages and a speculative page reference.
2786 Loading this module is safe if your kernel has the bug fixed.
2787 If the bug is not fixed, it will leak gigabytes of memory and
2788 probably OOM your system.
2789
4185b3b9
PA
2790config TEST_FPU
2791 tristate "Test floating point operations in kernel space"
2792 depends on X86 && !KCOV_INSTRUMENT_ALL
2793 help
2794 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2795 which will trigger a sequence of floating point operations. This is used
2796 for self-testing floating point control register setting in
2797 kernel_fpu_begin().
2798
2799 If unsure, say N.
2800
1253b9b8
PM
2801config TEST_CLOCKSOURCE_WATCHDOG
2802 tristate "Test clocksource watchdog in kernel space"
2803 depends on CLOCKSOURCE_WATCHDOG
2804 help
2805 Enable this option to create a kernel module that will trigger
2806 a test of the clocksource watchdog. This module may be loaded
2807 via modprobe or insmod in which case it will run upon being
2808 loaded, or it may be built in, in which case it will run
2809 shortly after boot.
2810
2811 If unsure, say N.
2812
d3deafaa 2813endif # RUNTIME_TESTING_MENU
cc3fa840 2814
dce44566
AK
2815config ARCH_USE_MEMTEST
2816 bool
2817 help
2818 An architecture should select this when it uses early_memtest()
2819 during boot process.
2820
cc3fa840
RD
2821config MEMTEST
2822 bool "Memtest"
dce44566 2823 depends on ARCH_USE_MEMTEST
a7f7f624 2824 help
cc3fa840 2825 This option adds a kernel parameter 'memtest', which allows memtest
dce44566 2826 to be set and executed.
cc3fa840
RD
2827 memtest=0, mean disabled; -- default
2828 memtest=1, mean do 1 test pattern;
2829 ...
2830 memtest=17, mean do 17 test patterns.
2831 If you are unsure how to answer this question, answer N.
2832
21266be9 2833
06ec64b8 2834
af9ca6f9
BB
2835config HYPERV_TESTING
2836 bool "Microsoft Hyper-V driver testing"
2837 default n
2838 depends on HYPERV && DEBUG_FS
2839 help
2840 Select this option to enable Hyper-V vmbus testing.
2841
045f6d79
CD
2842endmenu # "Kernel Testing and Coverage"
2843
2f7ab126
MO
2844menu "Rust hacking"
2845
2846config RUST_DEBUG_ASSERTIONS
2847 bool "Debug assertions"
2848 depends on RUST
2849 help
2850 Enables rustc's `-Cdebug-assertions` codegen option.
2851
2852 This flag lets you turn `cfg(debug_assertions)` conditional
2853 compilation on or off. This can be used to enable extra debugging
2854 code in development but not in production. For example, it controls
2855 the behavior of the standard library's `debug_assert!` macro.
2856
2857 Note that this will apply to all Rust code, including `core`.
2858
2859 If unsure, say N.
2860
2861config RUST_OVERFLOW_CHECKS
2862 bool "Overflow checks"
2863 default y
2864 depends on RUST
2865 help
2866 Enables rustc's `-Coverflow-checks` codegen option.
2867
2868 This flag allows you to control the behavior of runtime integer
2869 overflow. When overflow-checks are enabled, a Rust panic will occur
2870 on overflow.
2871
2872 Note that this will apply to all Rust code, including `core`.
2873
2874 If unsure, say Y.
2875
ecaa6ddf
GG
2876config RUST_BUILD_ASSERT_ALLOW
2877 bool "Allow unoptimized build-time assertions"
2878 depends on RUST
2879 help
2880 Controls how are `build_error!` and `build_assert!` handled during build.
2881
2882 If calls to them exist in the binary, it may indicate a violated invariant
2883 or that the optimizer failed to verify the invariant during compilation.
2884
2885 This should not happen, thus by default the build is aborted. However,
2886 as an escape hatch, you can choose Y here to ignore them during build
2887 and let the check be carried at runtime (with `panic!` being called if
2888 the check fails).
2889
2890 If unsure, say N.
2891
2f7ab126
MO
2892endmenu # "Rust"
2893
75442fb0
MCC
2894source "Documentation/Kconfig"
2895
06ec64b8 2896endmenu # Kernel hacking