Merge branch 'samples/bpf: modernize BPF functionality test programs'
[linux-block.git] / lib / Kconfig.debug
CommitLineData
ec8f24b7 1# SPDX-License-Identifier: GPL-2.0-only
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2menu "Kernel hacking"
3
604ff0dc 4menu "printk and dmesg options"
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5
6config PRINTK_TIME
7 bool "Show timing information on printks"
d3b8b6e5 8 depends on PRINTK
1da177e4 9 help
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10 Selecting this option causes time stamps of the printk()
11 messages to be added to the output of the syslog() system
12 call and at the console.
13
14 The timestamp is always recorded internally, and exported
15 to /dev/kmsg. This flag just specifies if the timestamp should
16 be included, not that the timestamp is recorded.
17
18 The behavior is also controlled by the kernel command line
8c27ceff 19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
1da177e4 20
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21config PRINTK_CALLER
22 bool "Show caller information on printks"
23 depends on PRINTK
24 help
25 Selecting this option causes printk() to add a caller "thread id" (if
26 in task context) or a caller "processor id" (if not in task context)
27 to every message.
28
29 This option is intended for environments where multiple threads
30 concurrently call printk() for many times, for it is difficult to
31 interpret without knowing where these lines (or sometimes individual
32 line which was divided into multiple lines due to race) came from.
33
34 Since toggling after boot makes the code racy, currently there is
35 no option to enable/disable at the kernel command line parameter or
36 sysfs interface.
37
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38config STACKTRACE_BUILD_ID
39 bool "Show build ID information in stacktraces"
40 depends on PRINTK
41 help
42 Selecting this option adds build ID information for symbols in
43 stacktraces printed with the printk format '%p[SR]b'.
44
45 This option is intended for distros where debuginfo is not easily
46 accessible but can be downloaded given the build ID of the vmlinux or
47 kernel module where the function is located.
48
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49config CONSOLE_LOGLEVEL_DEFAULT
50 int "Default console loglevel (1-15)"
51 range 1 15
52 default "7"
53 help
54 Default loglevel to determine what will be printed on the console.
55
56 Setting a default here is equivalent to passing in loglevel=<x> in
57 the kernel bootargs. loglevel=<x> continues to override whatever
58 value is specified here as well.
59
50f4d9bd 60 Note: This does not affect the log level of un-prefixed printk()
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61 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
62 option.
63
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64config CONSOLE_LOGLEVEL_QUIET
65 int "quiet console loglevel (1-15)"
66 range 1 15
67 default "4"
68 help
69 loglevel to use when "quiet" is passed on the kernel commandline.
70
71 When "quiet" is passed on the kernel commandline this loglevel
72 will be used as the loglevel. IOW passing "quiet" will be the
73 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
74
42a9dc0b 75config MESSAGE_LOGLEVEL_DEFAULT
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76 int "Default message log level (1-7)"
77 range 1 7
78 default "4"
79 help
80 Default log level for printk statements with no specified priority.
81
82 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83 that are auditing their logs closely may want to set it to a lower
84 priority.
85
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86 Note: This does not affect what message level gets printed on the console
87 by default. To change that, use loglevel=<x> in the kernel bootargs,
88 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
89
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90config BOOT_PRINTK_DELAY
91 bool "Delay each boot printk message by N milliseconds"
92 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
93 help
94 This build option allows you to read kernel boot messages
95 by inserting a short delay after each one. The delay is
96 specified in milliseconds on the kernel command line,
97 using "boot_delay=N".
98
99 It is likely that you would also need to use "lpj=M" to preset
100 the "loops per jiffie" value.
101 See a previous boot log for the "lpj" value to use for your
102 system, and then set "lpj=M" before setting "boot_delay=N".
103 NOTE: Using this option may adversely affect SMP systems.
104 I.e., processors other than the first one may not boot up.
105 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106 what it believes to be lockup conditions.
107
108config DYNAMIC_DEBUG
109 bool "Enable dynamic printk() support"
110 default n
111 depends on PRINTK
239a5791 112 depends on (DEBUG_FS || PROC_FS)
ceabef7d 113 select DYNAMIC_DEBUG_CORE
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114 help
115
116 Compiles debug level messages into the kernel, which would not
117 otherwise be available at runtime. These messages can then be
118 enabled/disabled based on various levels of scope - per source file,
119 function, module, format string, and line number. This mechanism
120 implicitly compiles in all pr_debug() and dev_dbg() calls, which
121 enlarges the kernel text size by about 2%.
122
123 If a source file is compiled with DEBUG flag set, any
124 pr_debug() calls in it are enabled by default, but can be
125 disabled at runtime as below. Note that DEBUG flag is
126 turned on by many CONFIG_*DEBUG* options.
127
128 Usage:
129
130 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
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131 which is contained in the 'debugfs' filesystem or procfs.
132 Thus, the debugfs or procfs filesystem must first be mounted before
133 making use of this feature.
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134 We refer the control file as: <debugfs>/dynamic_debug/control. This
135 file contains a list of the debug statements that can be enabled. The
136 format for each line of the file is:
137
138 filename:lineno [module]function flags format
139
140 filename : source file of the debug statement
141 lineno : line number of the debug statement
142 module : module that contains the debug statement
143 function : function that contains the debug statement
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144 flags : '=p' means the line is turned 'on' for printing
145 format : the format used for the debug statement
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146
147 From a live system:
148
149 nullarbor:~ # cat <debugfs>/dynamic_debug/control
150 # filename:lineno [module]function flags format
151 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154
155 Example usage:
156
157 // enable the message at line 1603 of file svcsock.c
158 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159 <debugfs>/dynamic_debug/control
160
161 // enable all the messages in file svcsock.c
162 nullarbor:~ # echo -n 'file svcsock.c +p' >
163 <debugfs>/dynamic_debug/control
164
165 // enable all the messages in the NFS server module
166 nullarbor:~ # echo -n 'module nfsd +p' >
167 <debugfs>/dynamic_debug/control
168
169 // enable all 12 messages in the function svc_process()
170 nullarbor:~ # echo -n 'func svc_process +p' >
171 <debugfs>/dynamic_debug/control
172
173 // disable all 12 messages in the function svc_process()
174 nullarbor:~ # echo -n 'func svc_process -p' >
175 <debugfs>/dynamic_debug/control
176
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177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
178 information.
604ff0dc 179
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180config DYNAMIC_DEBUG_CORE
181 bool "Enable core function of dynamic debug support"
182 depends on PRINTK
183 depends on (DEBUG_FS || PROC_FS)
184 help
185 Enable core functional support of dynamic debug. It is useful
186 when you want to tie dynamic debug to your kernel modules with
187 DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188 the case of embedded system where the kernel image size is
189 sensitive for people.
190
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191config SYMBOLIC_ERRNAME
192 bool "Support symbolic error names in printf"
193 default y if PRINTK
194 help
195 If you say Y here, the kernel's printf implementation will
196 be able to print symbolic error names such as ENOSPC instead
197 of the number 28. It makes the kernel image slightly larger
198 (about 3KB), but can make the kernel logs easier to read.
199
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200config DEBUG_BUGVERBOSE
201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
203 default y
204 help
205 Say Y here to make BUG() panics output the file name and line number
206 of the BUG call as well as the EIP and oops trace. This aids
207 debugging but costs about 70-100K of memory.
208
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209endmenu # "printk and dmesg options"
210
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211config DEBUG_KERNEL
212 bool "Kernel debugging"
213 help
214 Say Y here if you are developing drivers or trying to debug and
215 identify kernel problems.
216
217config DEBUG_MISC
218 bool "Miscellaneous debug code"
219 default DEBUG_KERNEL
220 depends on DEBUG_KERNEL
221 help
222 Say Y here if you need to enable miscellaneous debug code that should
223 be under a more specific debug option but isn't.
224
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225menu "Compile-time checks and compiler options"
226
227config DEBUG_INFO
f9b3cd24 228 bool
6dfc0665 229 help
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230 A kernel debug info option other than "None" has been selected
231 in the "Debug information" choice below, indicating that debug
232 information will be generated for build targets.
233
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234# Clang is known to generate .{s,u}leb128 with symbol deltas with DWARF5, which
235# some targets may not support: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
236config AS_HAS_NON_CONST_LEB128
237 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
238
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239choice
240 prompt "Debug information"
241 depends on DEBUG_KERNEL
242 help
243 Selecting something other than "None" results in a kernel image
244 that will include debugging info resulting in a larger kernel image.
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245 This adds debug symbols to the kernel and modules (gcc -g), and
246 is needed if you intend to use kernel crashdump or binary object
247 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
6dfc0665 248
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249 Choose which version of DWARF debug info to emit. If unsure,
250 select "Toolchain default".
251
252config DEBUG_INFO_NONE
253 bool "Disable debug information"
254 help
255 Do not build the kernel with debugging information, which will
256 result in a faster and smaller build.
257
258config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
259 bool "Rely on the toolchain's implicit default DWARF version"
260 select DEBUG_INFO
0a6de78c 261 depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
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262 help
263 The implicit default version of DWARF debug info produced by a
264 toolchain changes over time.
265
266 This can break consumers of the debug info that haven't upgraded to
267 support newer revisions, and prevent testing newer versions, but
268 those should be less common scenarios.
269
270config DEBUG_INFO_DWARF4
271 bool "Generate DWARF Version 4 debuginfo"
272 select DEBUG_INFO
4f001a21 273 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
f9b3cd24 274 help
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275 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
276 if using clang without clang's integrated assembler, and gdb 7.0+.
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277
278 If you have consumers of DWARF debug info that are not ready for
279 newer revisions of DWARF, you may wish to choose this or have your
280 config select this.
281
282config DEBUG_INFO_DWARF5
283 bool "Generate DWARF Version 5 debuginfo"
284 select DEBUG_INFO
0a6de78c 285 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
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286 help
287 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
288 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
289 draft features until 7.0), and gdb 8.0+.
290
291 Changes to the structure of debug info in Version 5 allow for around
292 15-18% savings in resulting image and debug info section sizes as
293 compared to DWARF Version 4. DWARF Version 5 standardizes previous
294 extensions such as accelerators for symbol indexing and the format
295 for fission (.dwo/.dwp) files. Users may not want to select this
296 config if they rely on tooling that has not yet been updated to
297 support DWARF Version 5.
298
299endchoice # "Debug information"
6dfc0665 300
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301if DEBUG_INFO
302
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303config DEBUG_INFO_REDUCED
304 bool "Reduce debugging information"
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305 help
306 If you say Y here gcc is instructed to generate less debugging
307 information for structure types. This means that tools that
308 need full debugging information (like kgdb or systemtap) won't
309 be happy. But if you merely need debugging information to
310 resolve line numbers there is no loss. Advantage is that
311 build directory object sizes shrink dramatically over a full
312 DEBUG_INFO build and compile times are reduced too.
313 Only works with newer gcc versions.
314
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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.
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391
392config DEBUG_INFO_BTF_MODULES
393 def_bool y
394 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
395 help
396 Generate compact split BTF type information for kernel modules.
397
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398config MODULE_ALLOW_BTF_MISMATCH
399 bool "Allow loading modules with non-matching BTF type info"
400 depends on DEBUG_INFO_BTF_MODULES
401 help
402 For modules whose split BTF does not match vmlinux, load without
403 BTF rather than refusing to load. The default behavior with
404 module BTF enabled is to reject modules with such mismatches;
405 this option will still load module BTF where possible but ignore
406 it when a mismatch is found.
407
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408config GDB_SCRIPTS
409 bool "Provide GDB scripts for kernel debugging"
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410 help
411 This creates the required links to GDB helper scripts in the
412 build directory. If you load vmlinux into gdb, the helper
413 scripts will be automatically imported by gdb as well, and
414 additional functions are available to analyze a Linux kernel
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415 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
416 for further details.
3ee7b3fa 417
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418endif # DEBUG_INFO
419
35bb5b1e 420config FRAME_WARN
a83e4ca2 421 int "Warn for stack frames larger than"
35bb5b1e 422 range 0 8192
ac66998d 423 default 0 if KMSAN
0e07f663 424 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
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425 default 2048 if PARISC
426 default 1536 if (!64BIT && XTENSA)
152fe65f 427 default 1280 if KASAN && !64BIT
8d192bec 428 default 1024 if !64BIT
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429 default 2048 if 64BIT
430 help
921757bc 431 Tell the compiler to warn at build time for stack frames larger than this.
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432 Setting this too low will cause a lot of warnings.
433 Setting it to 0 disables the warning.
35bb5b1e 434
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435config STRIP_ASM_SYMS
436 bool "Strip assembler-generated symbols during link"
437 default n
438 help
439 Strip internal assembler-generated symbols during a link (symbols
440 that look like '.Lxxx') so they don't pollute the output of
441 get_wchan() and suchlike.
442
1873e870 443config READABLE_ASM
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444 bool "Generate readable assembler code"
445 depends on DEBUG_KERNEL
7d73c3e9 446 depends on CC_IS_GCC
bf4735a4 447 help
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448 Disable some compiler optimizations that tend to generate human unreadable
449 assembler output. This may make the kernel slightly slower, but it helps
450 to keep kernel developers who have to stare a lot at assembler listings
451 sane.
bf4735a4 452
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453config HEADERS_INSTALL
454 bool "Install uapi headers to usr/include"
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455 depends on !UML
456 help
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457 This option will install uapi headers (headers exported to user-space)
458 into the usr/include directory for use during the kernel build.
459 This is unneeded for building the kernel itself, but needed for some
460 user-space program samples. It is also needed by some features such
461 as uapi header sanity checks.
462
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463config DEBUG_SECTION_MISMATCH
464 bool "Enable full Section mismatch analysis"
7d73c3e9 465 depends on CC_IS_GCC
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466 help
467 The section mismatch analysis checks if there are illegal
468 references from one section to another section.
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469 During linktime or runtime, some sections are dropped;
470 any use of code/data previously in these sections would
91341d4b 471 most likely result in an oops.
e809ab01 472 In the code, functions and variables are annotated with
0db0628d 473 __init,, etc. (see the full list in include/linux/init.h),
d6fbfa4f 474 which results in the code/data being placed in specific sections.
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475 The section mismatch analysis is always performed after a full
476 kernel build, and enabling this option causes the following
b7dca6dd 477 additional step to occur:
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478 - Add the option -fno-inline-functions-called-once to gcc commands.
479 When inlining a function annotated with __init in a non-init
480 function, we would lose the section information and thus
91341d4b 481 the analysis would not catch the illegal reference.
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482 This option tells gcc to inline less (but it does result in
483 a larger kernel).
91341d4b 484
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485config SECTION_MISMATCH_WARN_ONLY
486 bool "Make section mismatch errors non-fatal"
487 default y
488 help
489 If you say N here, the build process will fail if there are any
490 section mismatch, instead of just throwing warnings.
491
492 If unsure, say Y.
493
cf536e18 494config DEBUG_FORCE_FUNCTION_ALIGN_64B
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495 bool "Force all function address 64B aligned"
496 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
d49a0626 497 select FUNCTION_ALIGNMENT_64B
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498 help
499 There are cases that a commit from one domain changes the function
500 address alignment of other domains, and cause magic performance
501 bump (regression or improvement). Enable this option will help to
502 verify if the bump is caused by function alignment changes, while
503 it will slightly increase the kernel size and affect icache usage.
504
505 It is mainly for debug and performance tuning use.
506
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507#
508# Select this config option from the architecture Kconfig, if it
509# is preferred to always offer frame pointers as a config
510# option on the architecture (regardless of KERNEL_DEBUG):
511#
512config ARCH_WANT_FRAME_POINTERS
513 bool
f346f4b3 514
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515config FRAME_POINTER
516 bool "Compile the kernel with frame pointers"
a687a533 517 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
6dfc0665 518 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
a304e1b8 519 help
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520 If you say Y here the resulting kernel image will be slightly
521 larger and slower, but it gives very useful debugging information
522 in case of kernel bugs. (precise oopses/stacktraces/warnings)
a304e1b8 523
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524config OBJTOOL
525 bool
526
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527config STACK_VALIDATION
528 bool "Compile-time stack metadata validation"
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529 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
530 select OBJTOOL
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531 default n
532 help
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533 Validate frame pointer rules at compile-time. This helps ensure that
534 runtime stack traces are more reliable.
ee9f8fce 535
b9ab5ebb 536 For more information, see
d6a21f2d 537 tools/objtool/Documentation/objtool.txt.
b9ab5ebb 538
0f620cef 539config NOINSTR_VALIDATION
6804c1af 540 bool
489e355b 541 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
03f16cd0 542 select OBJTOOL
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543 default y
544
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545config VMLINUX_MAP
546 bool "Generate vmlinux.map file when linking"
547 depends on EXPERT
548 help
549 Selecting this option will pass "-Map=vmlinux.map" to ld
550 when linking vmlinux. That file can be useful for verifying
551 and debugging magic section games, and for seeing which
552 pieces of code get eliminated with
553 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
554
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555config DEBUG_FORCE_WEAK_PER_CPU
556 bool "Force weak per-cpu definitions"
557 depends on DEBUG_KERNEL
8446f1d3 558 help
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559 s390 and alpha require percpu variables in modules to be
560 defined weak to work around addressing range issue which
561 puts the following two restrictions on percpu variable
562 definitions.
8446f1d3 563
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564 1. percpu symbols must be unique whether static or not
565 2. percpu variables can't be defined inside a function
8446f1d3 566
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567 To ensure that generic code follows the above rules, this
568 option forces all percpu variables to be defined as weak.
5f329089 569
6dfc0665 570endmenu # "Compiler options"
8446f1d3 571
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572menu "Generic Kernel Debugging Instruments"
573
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574config MAGIC_SYSRQ
575 bool "Magic SysRq key"
576 depends on !UML
577 help
578 If you say Y here, you will have some control over the system even
579 if the system crashes for example during kernel debugging (e.g., you
580 will be able to flush the buffer cache to disk, reboot the system
581 immediately or dump some status information). This is accomplished
582 by pressing various keys while holding SysRq (Alt+PrintScreen). It
583 also works on a serial console (on PC hardware at least), if you
584 send a BREAK and then within 5 seconds a command keypress. The
f8998c22
HH
585 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
586 Don't say Y unless you really know what this hack does.
8446f1d3 587
8eaede49
BH
588config MAGIC_SYSRQ_DEFAULT_ENABLE
589 hex "Enable magic SysRq key functions by default"
590 depends on MAGIC_SYSRQ
591 default 0x1
592 help
593 Specifies which SysRq key functions are enabled by default.
594 This may be set to 1 or 0 to enable or disable them all, or
f8998c22 595 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
8eaede49 596
732dbf3a
FF
597config MAGIC_SYSRQ_SERIAL
598 bool "Enable magic SysRq key over serial"
599 depends on MAGIC_SYSRQ
600 default y
601 help
602 Many embedded boards have a disconnected TTL level serial which can
603 generate some garbage that can lead to spurious false sysrq detects.
604 This option allows you to decide whether you want to enable the
605 magic SysRq key.
606
68af4317
DS
607config MAGIC_SYSRQ_SERIAL_SEQUENCE
608 string "Char sequence that enables magic SysRq over serial"
609 depends on MAGIC_SYSRQ_SERIAL
610 default ""
611 help
612 Specifies a sequence of characters that can follow BREAK to enable
613 SysRq on a serial console.
614
d3394b3d
DS
615 If unsure, leave an empty string and the option will not be enabled.
616
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CD
617config DEBUG_FS
618 bool "Debug Filesystem"
619 help
620 debugfs is a virtual file system that kernel developers use to put
621 debugging files into. Enable this option to be able to read and
622 write to these files.
623
624 For detailed documentation on the debugfs API, see
625 Documentation/filesystems/.
626
627 If unsure, say N.
628
a24c6f7b
PE
629choice
630 prompt "Debugfs default access"
631 depends on DEBUG_FS
632 default DEBUG_FS_ALLOW_ALL
633 help
634 This selects the default access restrictions for debugfs.
635 It can be overridden with kernel command line option
636 debugfs=[on,no-mount,off]. The restrictions apply for API access
637 and filesystem registration.
638
639config DEBUG_FS_ALLOW_ALL
640 bool "Access normal"
641 help
642 No restrictions apply. Both API and filesystem registration
643 is on. This is the normal default operation.
644
645config DEBUG_FS_DISALLOW_MOUNT
646 bool "Do not register debugfs as filesystem"
647 help
648 The API is open but filesystem is not loaded. Clients can still do
649 their work and read with debug tools that do not need
650 debugfs filesystem.
651
652config DEBUG_FS_ALLOW_NONE
653 bool "No access"
654 help
655 Access is off. Clients get -PERM when trying to create nodes in
656 debugfs tree and debugfs is not registered as a filesystem.
657 Client can then back-off or continue without debugfs access.
658
659endchoice
660
6210b640 661source "lib/Kconfig.kgdb"
6210b640 662source "lib/Kconfig.ubsan"
2645d432 663source "lib/Kconfig.kcsan"
6210b640
CD
664
665endmenu
666
4d92b95f
ED
667menu "Networking Debugging"
668
669source "net/Kconfig.debug"
670
671endmenu # "Networking Debugging"
c66d7a27 672
0610c8a8 673menu "Memory Debugging"
fef2c9bc 674
8636a1f9 675source "mm/Kconfig.debug"
fef2c9bc 676
0610c8a8
DH
677config DEBUG_OBJECTS
678 bool "Debug object operations"
679 depends on DEBUG_KERNEL
9c44bc03 680 help
0610c8a8
DH
681 If you say Y here, additional code will be inserted into the
682 kernel to track the life time of various objects and validate
683 the operations on those objects.
9c44bc03 684
0610c8a8
DH
685config DEBUG_OBJECTS_SELFTEST
686 bool "Debug objects selftest"
687 depends on DEBUG_OBJECTS
688 help
689 This enables the selftest of the object debug code.
9c44bc03 690
0610c8a8
DH
691config DEBUG_OBJECTS_FREE
692 bool "Debug objects in freed memory"
693 depends on DEBUG_OBJECTS
694 help
695 This enables checks whether a k/v free operation frees an area
696 which contains an object which has not been deactivated
697 properly. This can make kmalloc/kfree-intensive workloads
698 much slower.
3ac7fe5a 699
c6f3a97f
TG
700config DEBUG_OBJECTS_TIMERS
701 bool "Debug timer objects"
702 depends on DEBUG_OBJECTS
703 help
704 If you say Y here, additional code will be inserted into the
705 timer routines to track the life time of timer objects and
706 validate the timer operations.
707
dc186ad7
TG
708config DEBUG_OBJECTS_WORK
709 bool "Debug work objects"
710 depends on DEBUG_OBJECTS
711 help
712 If you say Y here, additional code will be inserted into the
713 work queue routines to track the life time of work objects and
714 validate the work operations.
715
551d55a9
MD
716config DEBUG_OBJECTS_RCU_HEAD
717 bool "Debug RCU callbacks objects"
fc2ecf7e 718 depends on DEBUG_OBJECTS
551d55a9
MD
719 help
720 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
721
e2852ae8
TH
722config DEBUG_OBJECTS_PERCPU_COUNTER
723 bool "Debug percpu counter objects"
724 depends on DEBUG_OBJECTS
725 help
726 If you say Y here, additional code will be inserted into the
727 percpu counter routines to track the life time of percpu counter
728 objects and validate the percpu counter operations.
729
3ae70205
IM
730config DEBUG_OBJECTS_ENABLE_DEFAULT
731 int "debug_objects bootup default value (0-1)"
68d4b3df
KK
732 range 0 1
733 default "1"
734 depends on DEBUG_OBJECTS
735 help
736 Debug objects boot parameter default value
3ae70205 737
5035ebc6 738config SHRINKER_DEBUG
5035ebc6
RG
739 bool "Enable shrinker debugging support"
740 depends on DEBUG_FS
741 help
742 Say Y to enable the shrinker debugfs interface which provides
743 visibility into the kernel memory shrinkers subsystem.
744 Disable it to avoid an extra memory footprint.
745
b69ec42b
CM
746config HAVE_DEBUG_KMEMLEAK
747 bool
748
3bba00d7
CM
749config DEBUG_KMEMLEAK
750 bool "Kernel memory leak detector"
525c1f92 751 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
79e0d9bd 752 select DEBUG_FS
3bba00d7
CM
753 select STACKTRACE if STACKTRACE_SUPPORT
754 select KALLSYMS
b60e26a2 755 select CRC32
56a61617 756 select STACKDEPOT
3bba00d7
CM
757 help
758 Say Y here if you want to enable the memory leak
759 detector. The memory allocation/freeing is traced in a way
760 similar to the Boehm's conservative garbage collector, the
761 difference being that the orphan objects are not freed but
762 only shown in /sys/kernel/debug/kmemleak. Enabling this
763 feature will introduce an overhead to memory
700199b0 764 allocations. See Documentation/dev-tools/kmemleak.rst for more
3bba00d7
CM
765 details.
766
0610c8a8
DH
767 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
768 of finding leaks due to the slab objects poisoning.
769
770 In order to access the kmemleak file, debugfs needs to be
771 mounted (usually at /sys/kernel/debug).
772
c5665868
CM
773config DEBUG_KMEMLEAK_MEM_POOL_SIZE
774 int "Kmemleak memory pool size"
0610c8a8 775 depends on DEBUG_KMEMLEAK
c59180ae 776 range 200 1000000
b751c52b 777 default 16000
0610c8a8
DH
778 help
779 Kmemleak must track all the memory allocations to avoid
780 reporting false positives. Since memory may be allocated or
c5665868
CM
781 freed before kmemleak is fully initialised, use a static pool
782 of metadata objects to track such callbacks. After kmemleak is
783 fully initialised, this memory pool acts as an emergency one
784 if slab allocations fail.
0610c8a8
DH
785
786config DEBUG_KMEMLEAK_TEST
787 tristate "Simple test for the kernel memory leak detector"
788 depends on DEBUG_KMEMLEAK && m
789 help
790 This option enables a module that explicitly leaks memory.
791
792 If unsure, say N.
793
794config DEBUG_KMEMLEAK_DEFAULT_OFF
795 bool "Default kmemleak to off"
796 depends on DEBUG_KMEMLEAK
797 help
798 Say Y here to disable kmemleak by default. It can then be enabled
799 on the command line via kmemleak=on.
800
d53ce042
SK
801config DEBUG_KMEMLEAK_AUTO_SCAN
802 bool "Enable kmemleak auto scan thread on boot up"
803 default y
804 depends on DEBUG_KMEMLEAK
805 help
806 Depending on the cpu, kmemleak scan may be cpu intensive and can
807 stall user tasks at times. This option enables/disables automatic
808 kmemleak scan at boot up.
809
810 Say N here to disable kmemleak auto scan thread to stop automatic
811 scanning. Disabling this option disables automatic reporting of
812 memory leaks.
813
814 If unsure, say Y.
815
0610c8a8
DH
816config DEBUG_STACK_USAGE
817 bool "Stack utilization instrumentation"
6c31da34 818 depends on DEBUG_KERNEL && !IA64
0610c8a8
DH
819 help
820 Enables the display of the minimum amount of free stack which each
821 task has ever had available in the sysrq-T and sysrq-P debug output.
822
823 This option will slow down process creation somewhat.
824
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CD
825config SCHED_STACK_END_CHECK
826 bool "Detect stack corruption on calls to schedule()"
827 depends on DEBUG_KERNEL
828 default n
829 help
830 This option checks for a stack overrun on calls to schedule().
831 If the stack end location is found to be over written always panic as
832 the content of the corrupted region can no longer be trusted.
833 This is to ensure no erroneous behaviour occurs which could result in
834 data corruption or a sporadic crash at a later stage once the region
835 is examined. The runtime overhead introduced is minimal.
836
399145f9
AK
837config ARCH_HAS_DEBUG_VM_PGTABLE
838 bool
839 help
840 An architecture should select this when it can successfully
841 build and run DEBUG_VM_PGTABLE.
842
a738e9ba
TG
843config DEBUG_VM_IRQSOFF
844 def_bool DEBUG_VM && !PREEMPT_RT
845
0610c8a8
DH
846config DEBUG_VM
847 bool "Debug VM"
848 depends on DEBUG_KERNEL
849 help
850 Enable this to turn on extended checks in the virtual-memory system
68d4b3df 851 that may impact performance.
0610c8a8
DH
852
853 If unsure, say N.
854
54a611b6
LH
855config DEBUG_VM_MAPLE_TREE
856 bool "Debug VM maple trees"
4f115147 857 depends on DEBUG_VM
54a611b6 858 select DEBUG_MAPLE_TREE
4f115147 859 help
54a611b6 860 Enable VM maple tree debugging information and extra validations.
4f115147
DB
861
862 If unsure, say N.
863
0610c8a8
DH
864config DEBUG_VM_RB
865 bool "Debug VM red-black trees"
866 depends on DEBUG_VM
867 help
a663dad6 868 Enable VM red-black tree debugging information and extra validations.
0610c8a8
DH
869
870 If unsure, say N.
871
95ad9755
KS
872config DEBUG_VM_PGFLAGS
873 bool "Debug page-flags operations"
874 depends on DEBUG_VM
875 help
876 Enables extra validation on page flags operations.
877
878 If unsure, say N.
879
399145f9
AK
880config DEBUG_VM_PGTABLE
881 bool "Debug arch page table for semantics compliance"
882 depends on MMU
883 depends on ARCH_HAS_DEBUG_VM_PGTABLE
884 default y if DEBUG_VM
885 help
886 This option provides a debug method which can be used to test
887 architecture page table helper functions on various platforms in
888 verifying if they comply with expected generic MM semantics. This
889 will help architecture code in making sure that any changes or
890 new additions of these helpers still conform to expected
891 semantics of the generic MM. Platforms will have to opt in for
892 this through ARCH_HAS_DEBUG_VM_PGTABLE.
893
894 If unsure, say N.
895
fa5b6ec9
LA
896config ARCH_HAS_DEBUG_VIRTUAL
897 bool
898
0610c8a8
DH
899config DEBUG_VIRTUAL
900 bool "Debug VM translations"
fa5b6ec9 901 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
0610c8a8
DH
902 help
903 Enable some costly sanity checks in virtual to page code. This can
904 catch mistakes with virt_to_page() and friends.
905
906 If unsure, say N.
907
908config DEBUG_NOMMU_REGIONS
909 bool "Debug the global anon/private NOMMU mapping region tree"
910 depends on DEBUG_KERNEL && !MMU
911 help
912 This option causes the global tree of anonymous and private mapping
913 regions to be regularly checked for invalid topology.
914
915config DEBUG_MEMORY_INIT
916 bool "Debug memory initialisation" if EXPERT
917 default !EXPERT
918 help
919 Enable this for additional checks during memory initialisation.
920 The sanity checks verify aspects of the VM such as the memory model
921 and other information provided by the architecture. Verbose
922 information will be printed at KERN_DEBUG loglevel depending
923 on the mminit_loglevel= command-line option.
924
925 If unsure, say Y
926
927config MEMORY_NOTIFIER_ERROR_INJECT
928 tristate "Memory hotplug notifier error injection module"
50f9481e 929 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
0610c8a8
DH
930 help
931 This option provides the ability to inject artificial errors to
932 memory hotplug notifier chain callbacks. It is controlled through
933 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
934
935 If the notifier call chain should be failed with some events
936 notified, write the error code to "actions/<notifier event>/error".
937
938 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
939
940 # cd /sys/kernel/debug/notifier-error-inject/memory
941 # echo -12 > actions/MEM_GOING_OFFLINE/error
942 # echo offline > /sys/devices/system/memory/memoryXXX/state
943 bash: echo: write error: Cannot allocate memory
944
945 To compile this code as a module, choose M here: the module will
946 be called memory-notifier-error-inject.
947
948 If unsure, say N.
949
950config DEBUG_PER_CPU_MAPS
951 bool "Debug access to per_cpu maps"
952 depends on DEBUG_KERNEL
953 depends on SMP
954 help
955 Say Y to verify that the per_cpu map being accessed has
956 been set up. This adds a fair amount of code to kernel memory
957 and decreases performance.
958
959 Say N if unsure.
960
6e799cb6
TG
961config DEBUG_KMAP_LOCAL
962 bool "Debug kmap_local temporary mappings"
963 depends on DEBUG_KERNEL && KMAP_LOCAL
964 help
965 This option enables additional error checking for the kmap_local
966 infrastructure. Disable for production use.
967
0e91a0c6
TG
968config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
969 bool
970
971config DEBUG_KMAP_LOCAL_FORCE_MAP
972 bool "Enforce kmap_local temporary mappings"
973 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
974 select KMAP_LOCAL
975 select DEBUG_KMAP_LOCAL
976 help
977 This option enforces temporary mappings through the kmap_local
978 mechanism for non-highmem pages and on non-highmem systems.
979 Disable this for production systems!
980
0610c8a8
DH
981config DEBUG_HIGHMEM
982 bool "Highmem debugging"
983 depends on DEBUG_KERNEL && HIGHMEM
0e91a0c6 984 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
6e799cb6 985 select DEBUG_KMAP_LOCAL
0610c8a8 986 help
b1357c9f
GU
987 This option enables additional error checking for high memory
988 systems. Disable for production systems.
0610c8a8
DH
989
990config HAVE_DEBUG_STACKOVERFLOW
991 bool
992
993config DEBUG_STACKOVERFLOW
994 bool "Check for stack overflows"
995 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
a7f7f624 996 help
0610c8a8 997 Say Y here if you want to check for overflows of kernel, IRQ
edb0ec07 998 and exception stacks (if your architecture uses them). This
0610c8a8
DH
999 option will show detailed messages if free stack space drops
1000 below a certain limit.
1001
1002 These kinds of bugs usually occur when call-chains in the
1003 kernel get too deep, especially when interrupts are
1004 involved.
1005
1006 Use this in cases where you see apparently random memory
1007 corruption, especially if it appears in 'struct thread_info'
1008
1009 If in doubt, say "N".
1010
0b24becc 1011source "lib/Kconfig.kasan"
0ce20dd8 1012source "lib/Kconfig.kfence"
f80be457 1013source "lib/Kconfig.kmsan"
0b24becc 1014
0610c8a8
DH
1015endmenu # "Memory Debugging"
1016
a304e1b8
DW
1017config DEBUG_SHIRQ
1018 bool "Debug shared IRQ handlers"
0244ad00 1019 depends on DEBUG_KERNEL
a304e1b8 1020 help
0a2fae2a
WS
1021 Enable this to generate a spurious interrupt just before a shared
1022 interrupt handler is deregistered (generating one when registering
1023 is currently disabled). Drivers need to handle this correctly. Some
1024 don't and need to be caught.
a304e1b8 1025
f43a289d
CD
1026menu "Debug Oops, Lockups and Hangs"
1027
1028config PANIC_ON_OOPS
1029 bool "Panic on Oops"
1030 help
1031 Say Y here to enable the kernel to panic when it oopses. This
1032 has the same effect as setting oops=panic on the kernel command
1033 line.
1034
1035 This feature is useful to ensure that the kernel does not do
1036 anything erroneous after an oops which could result in data
1037 corruption or other issues.
1038
1039 Say N if unsure.
1040
1041config PANIC_ON_OOPS_VALUE
1042 int
1043 range 0 1
1044 default 0 if !PANIC_ON_OOPS
1045 default 1 if PANIC_ON_OOPS
1046
1047config PANIC_TIMEOUT
1048 int "panic timeout"
1049 default 0
1050 help
9d5b134f 1051 Set the timeout value (in seconds) until a reboot occurs when
f43a289d
CD
1052 the kernel panics. If n = 0, then we wait forever. A timeout
1053 value n > 0 will wait n seconds before rebooting, while a timeout
1054 value n < 0 will reboot immediately.
92aef8fb 1055
58687acb 1056config LOCKUP_DETECTOR
05a4a952
NP
1057 bool
1058
1059config SOFTLOCKUP_DETECTOR
1060 bool "Detect Soft Lockups"
dea20a3f 1061 depends on DEBUG_KERNEL && !S390
05a4a952 1062 select LOCKUP_DETECTOR
8446f1d3 1063 help
58687acb 1064 Say Y here to enable the kernel to act as a watchdog to detect
05a4a952 1065 soft lockups.
58687acb
DZ
1066
1067 Softlockups are bugs that cause the kernel to loop in kernel
5f329089 1068 mode for more than 20 seconds, without giving other tasks a
58687acb
DZ
1069 chance to run. The current stack trace is displayed upon
1070 detection and the system will stay locked up.
8446f1d3 1071
5f00ae0d
RD
1072config BOOTPARAM_SOFTLOCKUP_PANIC
1073 bool "Panic (Reboot) On Soft Lockups"
1074 depends on SOFTLOCKUP_DETECTOR
1075 help
1076 Say Y here to enable the kernel to panic on "soft lockups",
1077 which are bugs that cause the kernel to loop in kernel
1078 mode for more than 20 seconds (configurable using the watchdog_thresh
1079 sysctl), without giving other tasks a chance to run.
1080
1081 The panic can be used in combination with panic_timeout,
1082 to cause the system to reboot automatically after a
1083 lockup has been detected. This feature is useful for
1084 high-availability systems that have uptime guarantees and
1085 where a lockup must be resolved ASAP.
1086
1087 Say N if unsure.
1088
05a4a952
NP
1089config HARDLOCKUP_DETECTOR_PERF
1090 bool
1091 select SOFTLOCKUP_DETECTOR
1092
7edaeb68
TG
1093#
1094# Enables a timestamp based low pass filter to compensate for perf based
1095# hard lockup detection which runs too fast due to turbo modes.
1096#
1097config HARDLOCKUP_CHECK_TIMESTAMP
1098 bool
1099
05a4a952
NP
1100#
1101# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1102# lockup detector rather than the perf based detector.
1103#
1104config HARDLOCKUP_DETECTOR
1105 bool "Detect Hard Lockups"
1106 depends on DEBUG_KERNEL && !S390
1107 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1108 select LOCKUP_DETECTOR
1109 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
05a4a952
NP
1110 help
1111 Say Y here to enable the kernel to act as a watchdog to detect
1112 hard lockups.
1113
58687acb 1114 Hardlockups are bugs that cause the CPU to loop in kernel mode
5f329089 1115 for more than 10 seconds, without letting other interrupts have a
58687acb
DZ
1116 chance to run. The current stack trace is displayed upon detection
1117 and the system will stay locked up.
8446f1d3 1118
fef2c9bc
DZ
1119config BOOTPARAM_HARDLOCKUP_PANIC
1120 bool "Panic (Reboot) On Hard Lockups"
8f1f66ed 1121 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
1122 help
1123 Say Y here to enable the kernel to panic on "hard lockups",
1124 which are bugs that cause the kernel to loop in kernel
5f329089
FLVC
1125 mode with interrupts disabled for more than 10 seconds (configurable
1126 using the watchdog_thresh sysctl).
fef2c9bc
DZ
1127
1128 Say N if unsure.
1129
e162b39a
MSB
1130config DETECT_HUNG_TASK
1131 bool "Detect Hung Tasks"
1132 depends on DEBUG_KERNEL
05a4a952 1133 default SOFTLOCKUP_DETECTOR
e162b39a 1134 help
0610c8a8
DH
1135 Say Y here to enable the kernel to detect "hung tasks",
1136 which are bugs that cause the task to be stuck in
96b03ab8 1137 uninterruptible "D" state indefinitely.
1da177e4 1138
0610c8a8
DH
1139 When a hung task is detected, the kernel will print the
1140 current stack trace (which you should report), but the
1141 task will stay in uninterruptible state. If lockdep is
1142 enabled then all held locks will also be reported. This
1143 feature has negligible overhead.
871751e2 1144
0610c8a8
DH
1145config DEFAULT_HUNG_TASK_TIMEOUT
1146 int "Default timeout for hung task detection (in seconds)"
1147 depends on DETECT_HUNG_TASK
1148 default 120
f0630fff 1149 help
0610c8a8
DH
1150 This option controls the default timeout (in seconds) used
1151 to determine when a task has become non-responsive and should
1152 be considered hung.
f0630fff 1153
0610c8a8
DH
1154 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1155 sysctl or by writing a value to
1156 /proc/sys/kernel/hung_task_timeout_secs.
8ff12cfc 1157
0610c8a8
DH
1158 A timeout of 0 disables the check. The default is two minutes.
1159 Keeping the default should be fine in most cases.
b69ec42b 1160
0610c8a8
DH
1161config BOOTPARAM_HUNG_TASK_PANIC
1162 bool "Panic (Reboot) On Hung Tasks"
1163 depends on DETECT_HUNG_TASK
3bba00d7 1164 help
0610c8a8
DH
1165 Say Y here to enable the kernel to panic on "hung tasks",
1166 which are bugs that cause the kernel to leave a task stuck
1167 in uninterruptible "D" state.
3bba00d7 1168
0610c8a8
DH
1169 The panic can be used in combination with panic_timeout,
1170 to cause the system to reboot automatically after a
1171 hung task has been detected. This feature is useful for
1172 high-availability systems that have uptime guarantees and
1173 where a hung tasks must be resolved ASAP.
bf96d1e3 1174
0610c8a8 1175 Say N if unsure.
bf96d1e3 1176
82607adc
TH
1177config WQ_WATCHDOG
1178 bool "Detect Workqueue Stalls"
1179 depends on DEBUG_KERNEL
1180 help
1181 Say Y here to enable stall detection on workqueues. If a
1182 worker pool doesn't make forward progress on a pending work
1183 item for over a given amount of time, 30s by default, a
1184 warning message is printed along with dump of workqueue
1185 state. This can be configured through kernel parameter
1186 "workqueue.watchdog_thresh" and its sysfs counterpart.
1187
30428ef5
KK
1188config TEST_LOCKUP
1189 tristate "Test module to generate lockups"
63646bc9 1190 depends on m
30428ef5
KK
1191 help
1192 This builds the "test_lockup" module that helps to make sure
1193 that watchdogs and lockup detectors are working properly.
1194
1195 Depending on module parameters it could emulate soft or hard
1196 lockup, "hung task", or locking arbitrary lock for a long time.
1197 Also it could generate series of lockups with cooling-down periods.
1198
1199 If unsure, say N.
1200
92aef8fb
DH
1201endmenu # "Debug lockups and hangs"
1202
ebebdd09 1203menu "Scheduler Debugging"
5800dc3c 1204
0610c8a8
DH
1205config SCHED_DEBUG
1206 bool "Collect scheduler debugging info"
1207 depends on DEBUG_KERNEL && PROC_FS
1208 default y
0822ee4a 1209 help
0610c8a8
DH
1210 If you say Y here, the /proc/sched_debug file will be provided
1211 that can help debug the scheduler. The runtime overhead of this
1212 option is minimal.
0822ee4a 1213
f6db8347
NR
1214config SCHED_INFO
1215 bool
1216 default n
1217
0610c8a8
DH
1218config SCHEDSTATS
1219 bool "Collect scheduler statistics"
1220 depends on DEBUG_KERNEL && PROC_FS
f6db8347 1221 select SCHED_INFO
0610c8a8
DH
1222 help
1223 If you say Y here, additional code will be inserted into the
1224 scheduler and related routines to collect statistics about
1225 scheduler behavior and provide them in /proc/schedstat. These
1226 stats may be useful for both tuning and debugging the scheduler
1227 If you aren't debugging the scheduler or trying to tune a specific
1228 application, you can say N to avoid the very slight overhead
1229 this adds.
0822ee4a 1230
ebebdd09 1231endmenu
0d9e2632 1232
3c17ad19
JS
1233config DEBUG_TIMEKEEPING
1234 bool "Enable extra timekeeping sanity checking"
1235 help
1236 This option will enable additional timekeeping sanity checks
1237 which may be helpful when diagnosing issues where timekeeping
1238 problems are suspected.
1239
1240 This may include checks in the timekeeping hotpaths, so this
1241 option may have a (very small) performance impact to some
1242 workloads.
1243
1244 If unsure, say N.
1245
1da177e4
LT
1246config DEBUG_PREEMPT
1247 bool "Debug preemptible kernel"
9f472869 1248 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1da177e4
LT
1249 default y
1250 help
1251 If you say Y here then the kernel will use a debug variant of the
1252 commonly used smp_processor_id() function and will print warnings
1253 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1254 will detect preemption count underflows.
1255
9eade16b
DH
1256menu "Lock Debugging (spinlocks, mutexes, etc...)"
1257
f07cbebb
WL
1258config LOCK_DEBUGGING_SUPPORT
1259 bool
1260 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1261 default y
1262
19193bca
WL
1263config PROVE_LOCKING
1264 bool "Lock debugging: prove locking correctness"
1265 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1266 select LOCKDEP
1267 select DEBUG_SPINLOCK
bb630f9f 1268 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca 1269 select DEBUG_RT_MUTEXES if RT_MUTEXES
c71fd893 1270 select DEBUG_RWSEMS
19193bca
WL
1271 select DEBUG_WW_MUTEX_SLOWPATH
1272 select DEBUG_LOCK_ALLOC
8fd8ad5c 1273 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
19193bca
WL
1274 select TRACE_IRQFLAGS
1275 default n
1276 help
1277 This feature enables the kernel to prove that all locking
1278 that occurs in the kernel runtime is mathematically
1279 correct: that under no circumstance could an arbitrary (and
1280 not yet triggered) combination of observed locking
1281 sequences (on an arbitrary number of CPUs, running an
1282 arbitrary number of tasks and interrupt contexts) cause a
1283 deadlock.
1284
1285 In short, this feature enables the kernel to report locking
1286 related deadlocks before they actually occur.
1287
1288 The proof does not depend on how hard and complex a
1289 deadlock scenario would be to trigger: how many
1290 participant CPUs, tasks and irq-contexts would be needed
1291 for it to trigger. The proof also does not depend on
1292 timing: if a race and a resulting deadlock is possible
1293 theoretically (no matter how unlikely the race scenario
1294 is), it will be proven so and will immediately be
1295 reported by the kernel (once the event is observed that
1296 makes the deadlock theoretically possible).
1297
1298 If a deadlock is impossible (i.e. the locking rules, as
1299 observed by the kernel, are mathematically correct), the
1300 kernel reports nothing.
1301
1302 NOTE: this feature can also be enabled for rwlocks, mutexes
1303 and rwsems - in which case all dependencies between these
1304 different locking variants are observed and mapped too, and
1305 the proof of observed correctness is also maintained for an
1306 arbitrary combination of these separate locking variants.
1307
387b1468 1308 For more details, see Documentation/locking/lockdep-design.rst.
19193bca 1309
de8f5e4f
PZ
1310config PROVE_RAW_LOCK_NESTING
1311 bool "Enable raw_spinlock - spinlock nesting checks"
1312 depends on PROVE_LOCKING
1313 default n
1314 help
1315 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1316 that the lock nesting rules for PREEMPT_RT enabled kernels are
1317 not violated.
1318
1319 NOTE: There are known nesting problems. So if you enable this
1320 option expect lockdep splats until these problems have been fully
1321 addressed which is work in progress. This config switch allows to
1322 identify and analyze these problems. It will be removed and the
9dbbc3b9 1323 check permanently enabled once the main issues have been fixed.
de8f5e4f
PZ
1324
1325 If unsure, select N.
1326
19193bca
WL
1327config LOCK_STAT
1328 bool "Lock usage statistics"
1329 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1330 select LOCKDEP
1331 select DEBUG_SPINLOCK
bb630f9f 1332 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca
WL
1333 select DEBUG_RT_MUTEXES if RT_MUTEXES
1334 select DEBUG_LOCK_ALLOC
1335 default n
1336 help
1337 This feature enables tracking lock contention points
1338
387b1468 1339 For more details, see Documentation/locking/lockstat.rst
19193bca
WL
1340
1341 This also enables lock events required by "perf lock",
1342 subcommand of perf.
1343 If you want to use "perf lock", you also need to turn on
1344 CONFIG_EVENT_TRACING.
1345
1346 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1347 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1348
e7eebaf6
IM
1349config DEBUG_RT_MUTEXES
1350 bool "RT Mutex debugging, deadlock detection"
e7eebaf6
IM
1351 depends on DEBUG_KERNEL && RT_MUTEXES
1352 help
1353 This allows rt mutex semantics violations and rt mutex related
1354 deadlocks (lockups) to be detected and reported automatically.
1355
1da177e4 1356config DEBUG_SPINLOCK
4d9f34ad 1357 bool "Spinlock and rw-lock debugging: basic checks"
1da177e4 1358 depends on DEBUG_KERNEL
e335e3eb 1359 select UNINLINE_SPIN_UNLOCK
1da177e4
LT
1360 help
1361 Say Y here and build SMP to catch missing spinlock initialization
1362 and certain other kinds of spinlock errors commonly made. This is
1363 best used in conjunction with the NMI watchdog so that spinlock
1364 deadlocks are also debuggable.
1365
4d9f34ad
IM
1366config DEBUG_MUTEXES
1367 bool "Mutex debugging: basic checks"
bb630f9f 1368 depends on DEBUG_KERNEL && !PREEMPT_RT
4d9f34ad
IM
1369 help
1370 This feature allows mutex semantics violations to be detected and
1371 reported.
1372
23010027
DV
1373config DEBUG_WW_MUTEX_SLOWPATH
1374 bool "Wait/wound mutex debugging: Slowpath testing"
f07cbebb 1375 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
23010027
DV
1376 select DEBUG_LOCK_ALLOC
1377 select DEBUG_SPINLOCK
bb630f9f
TG
1378 select DEBUG_MUTEXES if !PREEMPT_RT
1379 select DEBUG_RT_MUTEXES if PREEMPT_RT
23010027
DV
1380 help
1381 This feature enables slowpath testing for w/w mutex users by
1382 injecting additional -EDEADLK wound/backoff cases. Together with
1383 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1384 will test all possible w/w mutex interface abuse with the
1385 exception of simply not acquiring all the required locks.
4d692373
RC
1386 Note that this feature can introduce significant overhead, so
1387 it really should not be enabled in a production or distro kernel,
1388 even a debug kernel. If you are a driver writer, enable it. If
1389 you are a distro, do not.
23010027 1390
5149cbac
WL
1391config DEBUG_RWSEMS
1392 bool "RW Semaphore debugging: basic checks"
c71fd893 1393 depends on DEBUG_KERNEL
5149cbac 1394 help
c71fd893
WL
1395 This debugging feature allows mismatched rw semaphore locks
1396 and unlocks to be detected and reported.
5149cbac 1397
4d9f34ad
IM
1398config DEBUG_LOCK_ALLOC
1399 bool "Lock debugging: detect incorrect freeing of live locks"
f07cbebb 1400 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1401 select DEBUG_SPINLOCK
bb630f9f 1402 select DEBUG_MUTEXES if !PREEMPT_RT
f5694788 1403 select DEBUG_RT_MUTEXES if RT_MUTEXES
4d9f34ad
IM
1404 select LOCKDEP
1405 help
1406 This feature will check whether any held lock (spinlock, rwlock,
1407 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1408 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1409 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1410 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1411 held during task exit.
1412
4d9f34ad
IM
1413config LOCKDEP
1414 bool
f07cbebb 1415 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1416 select STACKTRACE
4d9f34ad
IM
1417 select KALLSYMS
1418 select KALLSYMS_ALL
1419
395102db
DJ
1420config LOCKDEP_SMALL
1421 bool
1422
5dc33592
TH
1423config LOCKDEP_BITS
1424 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1425 depends on LOCKDEP && !LOCKDEP_SMALL
1426 range 10 30
1427 default 15
1428 help
1429 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1430
1431config LOCKDEP_CHAINS_BITS
1432 int "Bitsize for MAX_LOCKDEP_CHAINS"
1433 depends on LOCKDEP && !LOCKDEP_SMALL
1434 range 10 30
1435 default 16
1436 help
1437 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1438
1439config LOCKDEP_STACK_TRACE_BITS
1440 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1441 depends on LOCKDEP && !LOCKDEP_SMALL
1442 range 10 30
1443 default 19
1444 help
1445 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1446
1447config LOCKDEP_STACK_TRACE_HASH_BITS
1448 int "Bitsize for STACK_TRACE_HASH_SIZE"
1449 depends on LOCKDEP && !LOCKDEP_SMALL
1450 range 10 30
1451 default 14
1452 help
1453 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1454
1455config LOCKDEP_CIRCULAR_QUEUE_BITS
1456 int "Bitsize for elements in circular_queue struct"
1457 depends on LOCKDEP
1458 range 10 30
1459 default 12
1460 help
1461 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1462
4d9f34ad
IM
1463config DEBUG_LOCKDEP
1464 bool "Lock dependency engine debugging"
517e7aa5 1465 depends on DEBUG_KERNEL && LOCKDEP
997acaf6 1466 select DEBUG_IRQFLAGS
4d9f34ad
IM
1467 help
1468 If you say Y here, the lock dependency engine will do
1469 additional runtime checks to debug itself, at the price
1470 of more runtime overhead.
1471
d902db1e
FW
1472config DEBUG_ATOMIC_SLEEP
1473 bool "Sleep inside atomic section checking"
e8f7c70f 1474 select PREEMPT_COUNT
1da177e4 1475 depends on DEBUG_KERNEL
87a4c375 1476 depends on !ARCH_NO_PREEMPT
1da177e4
LT
1477 help
1478 If you say Y here, various routines which may sleep will become very
d902db1e
FW
1479 noisy if they are called inside atomic sections: when a spinlock is
1480 held, inside an rcu read side critical section, inside preempt disabled
1481 sections, inside an interrupt, etc...
1da177e4 1482
cae2ed9a
IM
1483config DEBUG_LOCKING_API_SELFTESTS
1484 bool "Locking API boot-time self-tests"
1485 depends on DEBUG_KERNEL
1486 help
1487 Say Y here if you want the kernel to run a short self-test during
1488 bootup. The self-test checks whether common types of locking bugs
1489 are detected by debugging mechanisms or not. (if you disable
9dbbc3b9 1490 lock debugging then those bugs won't be detected of course.)
cae2ed9a
IM
1491 The following locking APIs are covered: spinlocks, rwlocks,
1492 mutexes and rwsems.
1493
0af3fe1e
PM
1494config LOCK_TORTURE_TEST
1495 tristate "torture tests for locking"
1496 depends on DEBUG_KERNEL
1497 select TORTURE_TEST
0af3fe1e
PM
1498 help
1499 This option provides a kernel module that runs torture tests
1500 on kernel locking primitives. The kernel module may be built
1501 after the fact on the running kernel to be tested, if desired.
1502
1503 Say Y here if you want kernel locking-primitive torture tests
1504 to be built into the kernel.
1505 Say M if you want these torture tests to build as a module.
1506 Say N if you are unsure.
1507
f2a5fec1
CW
1508config WW_MUTEX_SELFTEST
1509 tristate "Wait/wound mutex selftests"
1510 help
1511 This option provides a kernel module that runs tests on the
1512 on the struct ww_mutex locking API.
1513
1514 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1515 with this test harness.
1516
1517 Say M if you want these self tests to build as a module.
1518 Say N if you are unsure.
1519
e9d338a0
PM
1520config SCF_TORTURE_TEST
1521 tristate "torture tests for smp_call_function*()"
1522 depends on DEBUG_KERNEL
1523 select TORTURE_TEST
1524 help
1525 This option provides a kernel module that runs torture tests
1526 on the smp_call_function() family of primitives. The kernel
1527 module may be built after the fact on the running kernel to
1528 be tested, if desired.
1529
35feb604
PM
1530config CSD_LOCK_WAIT_DEBUG
1531 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1532 depends on DEBUG_KERNEL
1533 depends on 64BIT
1534 default n
1535 help
1536 This option enables debug prints when CPUs are slow to respond
1537 to the smp_call_function*() IPI wrappers. These debug prints
1538 include the IPI handler function currently executing (if any)
1539 and relevant stack traces.
1540
9eade16b 1541endmenu # lock debugging
8637c099 1542
9eade16b 1543config TRACE_IRQFLAGS
ed004953 1544 depends on TRACE_IRQFLAGS_SUPPORT
9eade16b 1545 bool
5ca43f6c 1546 help
9eade16b
DH
1547 Enables hooks to interrupt enabling and disabling for
1548 either tracing or lock debugging.
5ca43f6c 1549
ed004953 1550config TRACE_IRQFLAGS_NMI
1551 def_bool y
1552 depends on TRACE_IRQFLAGS
1553 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1554
997acaf6
MR
1555config DEBUG_IRQFLAGS
1556 bool "Debug IRQ flag manipulation"
1557 help
1558 Enables checks for potentially unsafe enabling or disabling of
1559 interrupts, such as calling raw_local_irq_restore() when interrupts
1560 are enabled.
1561
8637c099 1562config STACKTRACE
0c38e1fe 1563 bool "Stack backtrace support"
8637c099 1564 depends on STACKTRACE_SUPPORT
0c38e1fe
DJ
1565 help
1566 This option causes the kernel to create a /proc/pid/stack for
1567 every process, showing its current stack trace.
1568 It is also used by various kernel debugging features that require
1569 stack trace generation.
5ca43f6c 1570
eecabf56
TT
1571config WARN_ALL_UNSEEDED_RANDOM
1572 bool "Warn for all uses of unseeded randomness"
1573 default n
d06bfd19
JD
1574 help
1575 Some parts of the kernel contain bugs relating to their use of
1576 cryptographically secure random numbers before it's actually possible
1577 to generate those numbers securely. This setting ensures that these
1578 flaws don't go unnoticed, by enabling a message, should this ever
1579 occur. This will allow people with obscure setups to know when things
1580 are going wrong, so that they might contact developers about fixing
1581 it.
1582
eecabf56
TT
1583 Unfortunately, on some models of some architectures getting
1584 a fully seeded CRNG is extremely difficult, and so this can
1585 result in dmesg getting spammed for a surprisingly long
1586 time. This is really bad from a security perspective, and
1587 so architecture maintainers really need to do what they can
1588 to get the CRNG seeded sooner after the system is booted.
4c5d114e 1589 However, since users cannot do anything actionable to
cc1e127b 1590 address this, by default this option is disabled.
eecabf56
TT
1591
1592 Say Y here if you want to receive warnings for all uses of
1593 unseeded randomness. This will be of use primarily for
4c5d114e 1594 those developers interested in improving the security of
eecabf56
TT
1595 Linux kernels running on their architecture (or
1596 subarchitecture).
d06bfd19 1597
1da177e4
LT
1598config DEBUG_KOBJECT
1599 bool "kobject debugging"
1600 depends on DEBUG_KERNEL
1601 help
1602 If you say Y here, some extra kobject debugging messages will be sent
aca52c39 1603 to the syslog.
1da177e4 1604
c817a67e
RK
1605config DEBUG_KOBJECT_RELEASE
1606 bool "kobject release debugging"
2a999aa0 1607 depends on DEBUG_OBJECTS_TIMERS
c817a67e
RK
1608 help
1609 kobjects are reference counted objects. This means that their
1610 last reference count put is not predictable, and the kobject can
b6c69474 1611 live on past the point at which a driver decides to drop its
c817a67e
RK
1612 initial reference to the kobject gained on allocation. An
1613 example of this would be a struct device which has just been
1614 unregistered.
1615
1616 However, some buggy drivers assume that after such an operation,
1617 the memory backing the kobject can be immediately freed. This
1618 goes completely against the principles of a refcounted object.
1619
1620 If you say Y here, the kernel will delay the release of kobjects
1621 on the last reference count to improve the visibility of this
1622 kind of kobject release bug.
1623
9b2a60c4
CM
1624config HAVE_DEBUG_BUGVERBOSE
1625 bool
1626
3be5cbcd 1627menu "Debug kernel data structures"
1da177e4 1628
199a9afc
DJ
1629config DEBUG_LIST
1630 bool "Debug linked list manipulation"
4520bcb2 1631 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
199a9afc
DJ
1632 help
1633 Enable this to turn on extended checks in the linked-list
1634 walking routines.
1635
1636 If unsure, say N.
1637
8e18faea 1638config DEBUG_PLIST
b8cfff68
DS
1639 bool "Debug priority linked list manipulation"
1640 depends on DEBUG_KERNEL
1641 help
1642 Enable this to turn on extended checks in the priority-ordered
1643 linked-list (plist) walking routines. This checks the entire
1644 list multiple times during each manipulation.
1645
1646 If unsure, say N.
1647
d6ec0842
JA
1648config DEBUG_SG
1649 bool "Debug SG table operations"
1650 depends on DEBUG_KERNEL
1651 help
1652 Enable this to turn on checks on scatter-gather tables. This can
1653 help find problems with drivers that do not properly initialize
1654 their sg tables.
1655
1656 If unsure, say N.
1657
1b2439db
AV
1658config DEBUG_NOTIFIERS
1659 bool "Debug notifier call chains"
1660 depends on DEBUG_KERNEL
1661 help
1662 Enable this to turn on sanity checking for notifier call chains.
1663 This is most useful for kernel developers to make sure that
1664 modules properly unregister themselves from notifier chains.
1665 This is a relatively cheap check but if you care about maximum
1666 performance, say N.
1667
3be5cbcd
CD
1668config BUG_ON_DATA_CORRUPTION
1669 bool "Trigger a BUG when data corruption is detected"
1670 select DEBUG_LIST
1671 help
1672 Select this option if the kernel should BUG when it encounters
1673 data corruption in kernel memory structures when they get checked
1674 for validity.
1675
1676 If unsure, say N.
1677
54a611b6
LH
1678config DEBUG_MAPLE_TREE
1679 bool "Debug maple trees"
1680 depends on DEBUG_KERNEL
1681 help
1682 Enable maple tree debugging information and extra validations.
1683
1684 If unsure, say N.
1685
3be5cbcd
CD
1686endmenu
1687
e0e81739
DH
1688config DEBUG_CREDENTIALS
1689 bool "Debug credential management"
1690 depends on DEBUG_KERNEL
1691 help
1692 Enable this to turn on some debug checking for credential
1693 management. The additional code keeps track of the number of
1694 pointers from task_structs to any given cred struct, and checks to
1695 see that this number never exceeds the usage count of the cred
1696 struct.
1697
1698 Furthermore, if SELinux is enabled, this also checks that the
1699 security pointer in the cred struct is never seen to be invalid.
1700
1701 If unsure, say N.
1702
43a0a2a7 1703source "kernel/rcu/Kconfig.debug"
2f03e3ca 1704
f303fccb
TH
1705config DEBUG_WQ_FORCE_RR_CPU
1706 bool "Force round-robin CPU selection for unbound work items"
1707 depends on DEBUG_KERNEL
1708 default n
1709 help
1710 Workqueue used to implicitly guarantee that work items queued
1711 without explicit CPU specified are put on the local CPU. This
1712 guarantee is no longer true and while local CPU is still
1713 preferred work items may be put on foreign CPUs. Kernel
1714 parameter "workqueue.debug_force_rr_cpu" is added to force
1715 round-robin CPU selection to flush out usages which depend on the
1716 now broken guarantee. This config option enables the debug
1717 feature by default. When enabled, memory and cache locality will
1718 be impacted.
1719
757c989b
TG
1720config CPU_HOTPLUG_STATE_CONTROL
1721 bool "Enable CPU hotplug state control"
1722 depends on DEBUG_KERNEL
1723 depends on HOTPLUG_CPU
1724 default n
1725 help
1726 Allows to write steps between "offline" and "online" to the CPUs
1727 sysfs target file so states can be stepped granular. This is a debug
1728 option for now as the hotplug machinery cannot be stopped and
1729 restarted at arbitrary points yet.
1730
1731 Say N if your are unsure.
1732
09a74952
CD
1733config LATENCYTOP
1734 bool "Latency measuring infrastructure"
1735 depends on DEBUG_KERNEL
1736 depends on STACKTRACE_SUPPORT
1737 depends on PROC_FS
7d37cb2c 1738 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
09a74952
CD
1739 select KALLSYMS
1740 select KALLSYMS_ALL
1741 select STACKTRACE
1742 select SCHEDSTATS
09a74952
CD
1743 help
1744 Enable this option if you want to use the LatencyTOP tool
1745 to find out which userspace is blocking on what kernel operations.
1746
6ab42860
TH
1747config DEBUG_CGROUP_REF
1748 bool "Disable inlining of cgroup css reference count functions"
1749 depends on DEBUG_KERNEL
1750 depends on CGROUPS
1751 depends on KPROBES
1752 default n
1753 help
1754 Force cgroup css reference count functions to not be inlined so
1755 that they can be kprobed for debugging.
1756
09a74952
CD
1757source "kernel/trace/Kconfig"
1758
1759config PROVIDE_OHCI1394_DMA_INIT
1760 bool "Remote debugging over FireWire early on boot"
1761 depends on PCI && X86
1762 help
1763 If you want to debug problems which hang or crash the kernel early
1764 on boot and the crashing machine has a FireWire port, you can use
1765 this feature to remotely access the memory of the crashed machine
1766 over FireWire. This employs remote DMA as part of the OHCI1394
1767 specification which is now the standard for FireWire controllers.
1768
1769 With remote DMA, you can monitor the printk buffer remotely using
1770 firescope and access all memory below 4GB using fireproxy from gdb.
1771 Even controlling a kernel debugger is possible using remote DMA.
1772
1773 Usage:
1774
1775 If ohci1394_dma=early is used as boot parameter, it will initialize
1776 all OHCI1394 controllers which are found in the PCI config space.
1777
1778 As all changes to the FireWire bus such as enabling and disabling
1779 devices cause a bus reset and thereby disable remote DMA for all
1780 devices, be sure to have the cable plugged and FireWire enabled on
1781 the debugging host before booting the debug target for debugging.
1782
1783 This code (~1k) is freed after boot. By then, the firewire stack
1784 in charge of the OHCI-1394 controllers should be used instead.
1785
a74e2a22 1786 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
09a74952 1787
045f6d79
CD
1788source "samples/Kconfig"
1789
1790config ARCH_HAS_DEVMEM_IS_ALLOWED
1791 bool
1792
1793config STRICT_DEVMEM
1794 bool "Filter access to /dev/mem"
1795 depends on MMU && DEVMEM
527701ed 1796 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
045f6d79
CD
1797 default y if PPC || X86 || ARM64
1798 help
1799 If this option is disabled, you allow userspace (root) access to all
1800 of memory, including kernel and userspace memory. Accidental
1801 access to this is obviously disastrous, but specific access can
1802 be used by people debugging the kernel. Note that with PAT support
1803 enabled, even in this case there are restrictions on /dev/mem
1804 use due to the cache aliasing requirements.
1805
1806 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1807 file only allows userspace access to PCI space and the BIOS code and
1808 data regions. This is sufficient for dosemu and X and all common
1809 users of /dev/mem.
1810
1811 If in doubt, say Y.
1812
1813config IO_STRICT_DEVMEM
1814 bool "Filter I/O access to /dev/mem"
1815 depends on STRICT_DEVMEM
1816 help
1817 If this option is disabled, you allow userspace (root) access to all
1818 io-memory regardless of whether a driver is actively using that
1819 range. Accidental access to this is obviously disastrous, but
1820 specific access can be used by people debugging kernel drivers.
1821
1822 If this option is switched on, the /dev/mem file only allows
1823 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1824 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1825 if the driver using a given range cannot be disabled.
1826
1827 If in doubt, say Y.
1828
1829menu "$(SRCARCH) Debugging"
1830
1831source "arch/$(SRCARCH)/Kconfig.debug"
1832
1833endmenu
1834
1835menu "Kernel Testing and Coverage"
1836
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1837source "lib/kunit/Kconfig"
1838
8d438288
AM
1839config NOTIFIER_ERROR_INJECTION
1840 tristate "Notifier error injection"
1841 depends on DEBUG_KERNEL
1842 select DEBUG_FS
1843 help
e41e85cc 1844 This option provides the ability to inject artificial errors to
8d438288
AM
1845 specified notifier chain callbacks. It is useful to test the error
1846 handling of notifier call chain failures.
1847
1848 Say N if unsure.
1849
048b9c35
AM
1850config PM_NOTIFIER_ERROR_INJECT
1851 tristate "PM notifier error injection module"
1852 depends on PM && NOTIFIER_ERROR_INJECTION
1853 default m if PM_DEBUG
1854 help
e41e85cc 1855 This option provides the ability to inject artificial errors to
048b9c35
AM
1856 PM notifier chain callbacks. It is controlled through debugfs
1857 interface /sys/kernel/debug/notifier-error-inject/pm
1858
1859 If the notifier call chain should be failed with some events
1860 notified, write the error code to "actions/<notifier event>/error".
1861
1862 Example: Inject PM suspend error (-12 = -ENOMEM)
1863
1864 # cd /sys/kernel/debug/notifier-error-inject/pm/
1865 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1866 # echo mem > /sys/power/state
1867 bash: echo: write error: Cannot allocate memory
1868
1869 To compile this code as a module, choose M here: the module will
1870 be called pm-notifier-error-inject.
1871
1872 If unsure, say N.
1873
d526e85f
BH
1874config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1875 tristate "OF reconfig notifier error injection module"
1876 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dd 1877 help
e41e85cc 1878 This option provides the ability to inject artificial errors to
d526e85f 1879 OF reconfig notifier chain callbacks. It is controlled
08dfb4dd 1880 through debugfs interface under
d526e85f 1881 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
08dfb4dd
AM
1882
1883 If the notifier call chain should be failed with some events
1884 notified, write the error code to "actions/<notifier event>/error".
1885
1886 To compile this code as a module, choose M here: the module will
e12a95f4 1887 be called of-reconfig-notifier-error-inject.
08dfb4dd
AM
1888
1889 If unsure, say N.
1890
02fff96a
NA
1891config NETDEV_NOTIFIER_ERROR_INJECT
1892 tristate "Netdev notifier error injection module"
1893 depends on NET && NOTIFIER_ERROR_INJECTION
1894 help
1895 This option provides the ability to inject artificial errors to
1896 netdevice notifier chain callbacks. It is controlled through debugfs
1897 interface /sys/kernel/debug/notifier-error-inject/netdev
1898
1899 If the notifier call chain should be failed with some events
1900 notified, write the error code to "actions/<notifier event>/error".
1901
1902 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1903
1904 # cd /sys/kernel/debug/notifier-error-inject/netdev
1905 # echo -22 > actions/NETDEV_CHANGEMTU/error
1906 # ip link set eth0 mtu 1024
1907 RTNETLINK answers: Invalid argument
1908
1909 To compile this code as a module, choose M here: the module will
1910 be called netdev-notifier-error-inject.
1911
1912 If unsure, say N.
1913
f1b4bd06 1914config FUNCTION_ERROR_INJECTION
a4412fdd 1915 bool "Fault-injections of functions"
f1b4bd06 1916 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
a4412fdd
SRG
1917 help
1918 Add fault injections into various functions that are annotated with
1919 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1920 value of theses functions. This is useful to test error paths of code.
1921
1922 If unsure, say N
f1b4bd06 1923
6ff1cb35 1924config FAULT_INJECTION
1ab8509a
AM
1925 bool "Fault-injection framework"
1926 depends on DEBUG_KERNEL
329409ae
AM
1927 help
1928 Provide fault-injection framework.
1929 For more details, see Documentation/fault-injection/.
6ff1cb35 1930
8a8b6502 1931config FAILSLAB
1ab8509a
AM
1932 bool "Fault-injection capability for kmalloc"
1933 depends on FAULT_INJECTION
773ff60e 1934 depends on SLAB || SLUB
8a8b6502 1935 help
1ab8509a 1936 Provide fault-injection capability for kmalloc.
8a8b6502 1937
933e312e 1938config FAIL_PAGE_ALLOC
29b46fa3 1939 bool "Fault-injection capability for alloc_pages()"
1ab8509a 1940 depends on FAULT_INJECTION
933e312e 1941 help
1ab8509a 1942 Provide fault-injection capability for alloc_pages().
933e312e 1943
2c739ced
AL
1944config FAULT_INJECTION_USERCOPY
1945 bool "Fault injection capability for usercopy functions"
1946 depends on FAULT_INJECTION
1947 help
1948 Provides fault-injection capability to inject failures
1949 in usercopy functions (copy_from_user(), get_user(), ...).
1950
c17bb495 1951config FAIL_MAKE_REQUEST
86327d19 1952 bool "Fault-injection capability for disk IO"
581d4e28 1953 depends on FAULT_INJECTION && BLOCK
c17bb495 1954 help
1ab8509a 1955 Provide fault-injection capability for disk IO.
c17bb495 1956
581d4e28 1957config FAIL_IO_TIMEOUT
f4d01439 1958 bool "Fault-injection capability for faking disk interrupts"
581d4e28
JA
1959 depends on FAULT_INJECTION && BLOCK
1960 help
1961 Provide fault-injection capability on end IO handling. This
1962 will make the block layer "forget" an interrupt as configured,
1963 thus exercising the error handling.
1964
1965 Only works with drivers that use the generic timeout handling,
9dbbc3b9 1966 for others it won't do anything.
581d4e28 1967
ab51fbab
DB
1968config FAIL_FUTEX
1969 bool "Fault-injection capability for futexes"
1970 select DEBUG_FS
1971 depends on FAULT_INJECTION && FUTEX
1972 help
1973 Provide fault-injection capability for futexes.
1974
f1b4bd06
MP
1975config FAULT_INJECTION_DEBUG_FS
1976 bool "Debugfs entries for fault-injection capabilities"
1977 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1978 help
1979 Enable configuration of fault-injection capabilities via debugfs.
1980
4b1a29a7
MH
1981config FAIL_FUNCTION
1982 bool "Fault-injection capability for functions"
1983 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1984 help
1985 Provide function-based fault-injection capability.
1986 This will allow you to override a specific function with a return
1987 with given return value. As a result, function caller will see
1988 an error value and have to handle it. This is useful to test the
1989 error handling in various subsystems.
1990
f1b4bd06
MP
1991config FAIL_MMC_REQUEST
1992 bool "Fault-injection capability for MMC IO"
1993 depends on FAULT_INJECTION_DEBUG_FS && MMC
6ff1cb35 1994 help
f1b4bd06
MP
1995 Provide fault-injection capability for MMC IO.
1996 This will make the mmc core return data errors. This is
1997 useful to test the error handling in the mmc block device
1998 and to test how the mmc host driver handles retries from
1999 the block device.
1df49008 2000
c782af25
CL
2001config FAIL_SUNRPC
2002 bool "Fault-injection capability for SunRPC"
2003 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2004 help
2005 Provide fault-injection capability for SunRPC and
2006 its consumers.
2007
1df49008
AM
2008config FAULT_INJECTION_STACKTRACE_FILTER
2009 bool "stacktrace filter for fault-injection capabilities"
2010 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2011 select STACKTRACE
7d37cb2c 2012 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1df49008
AM
2013 help
2014 Provide stacktrace filter for fault-injection capabilities
267c4025 2015
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CD
2016config ARCH_HAS_KCOV
2017 bool
cc3fa840 2018 help
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CD
2019 An architecture should select this when it can successfully
2020 build and run with CONFIG_KCOV. This typically requires
2021 disabling instrumentation for some early boot code.
cc3fa840 2022
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CD
2023config CC_HAS_SANCOV_TRACE_PC
2024 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
cc3fa840 2025
cc3fa840 2026
09a74952
CD
2027config KCOV
2028 bool "Code coverage for fuzzing"
2029 depends on ARCH_HAS_KCOV
2030 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
22102f45 2031 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
bece04b5 2032 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
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CD
2033 select DEBUG_FS
2034 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
22102f45 2035 select OBJTOOL if HAVE_NOINSTR_HACK
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CD
2036 help
2037 KCOV exposes kernel code coverage information in a form suitable
2038 for coverage-guided fuzzing (randomized testing).
cc3fa840 2039
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CD
2040 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2041 different machines and across reboots. If you need stable PC values,
2042 disable RANDOMIZE_BASE.
cc3fa840 2043
09a74952 2044 For more details, see Documentation/dev-tools/kcov.rst.
cc3fa840 2045
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CD
2046config KCOV_ENABLE_COMPARISONS
2047 bool "Enable comparison operands collection by KCOV"
2048 depends on KCOV
2049 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2050 help
2051 KCOV also exposes operands of every comparison in the instrumented
2052 code along with operand sizes and PCs of the comparison instructions.
2053 These operands can be used by fuzzing engines to improve the quality
2054 of fuzzing coverage.
cc3fa840 2055
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CD
2056config KCOV_INSTRUMENT_ALL
2057 bool "Instrument all code by default"
2058 depends on KCOV
2059 default y
2060 help
2061 If you are doing generic system call fuzzing (like e.g. syzkaller),
2062 then you will want to instrument the whole kernel and you should
2063 say y here. If you are doing more targeted fuzzing (like e.g.
2064 filesystem fuzzing with AFL) then you will want to enable coverage
2065 for more specific subsets of files, and should say n here.
84bc809e 2066
5ff3b30a
AK
2067config KCOV_IRQ_AREA_SIZE
2068 hex "Size of interrupt coverage collection area in words"
2069 depends on KCOV
2070 default 0x40000
2071 help
2072 KCOV uses preallocated per-cpu areas to collect coverage from
2073 soft interrupts. This specifies the size of those areas in the
2074 number of unsigned long words.
2075
d3deafaa
VL
2076menuconfig RUNTIME_TESTING_MENU
2077 bool "Runtime Testing"
908009e8 2078 def_bool y
d3deafaa
VL
2079
2080if RUNTIME_TESTING_MENU
881c5149
DH
2081
2082config LKDTM
2083 tristate "Linux Kernel Dump Test Tool Module"
2084 depends on DEBUG_FS
881c5149
DH
2085 help
2086 This module enables testing of the different dumping mechanisms by
2087 inducing system failures at predefined crash points.
2088 If you don't need it: say N
2089 Choose M here to compile this code as a module. The module will be
2090 called lkdtm.
2091
2092 Documentation on how to use the module can be found in
10ffebbe 2093 Documentation/fault-injection/provoke-crashes.rst
881c5149 2094
d3c0ca49
SV
2095config CPUMASK_KUNIT_TEST
2096 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
c41e8866
SV
2097 depends on KUNIT
2098 default KUNIT_ALL_TESTS
2099 help
2100 Enable to turn on cpumask tests, running at boot or module load time.
2101
d3c0ca49
SV
2102 For more information on KUnit and unit tests in general, please refer
2103 to the KUnit documentation in Documentation/dev-tools/kunit/.
2104
c41e8866
SV
2105 If unsure, say N.
2106
881c5149 2107config TEST_LIST_SORT
ebd09577
DL
2108 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2109 depends on KUNIT
2110 default KUNIT_ALL_TESTS
881c5149
DH
2111 help
2112 Enable this to turn on 'list_sort()' function test. This test is
e327fd7c
GU
2113 executed only once during system boot (so affects only boot time),
2114 or at module load time.
881c5149
DH
2115
2116 If unsure, say N.
2117
6e24628d
IR
2118config TEST_MIN_HEAP
2119 tristate "Min heap test"
2120 depends on DEBUG_KERNEL || m
2121 help
2122 Enable this to turn on min heap function tests. This test is
2123 executed only once during system boot (so affects only boot time),
2124 or at module load time.
2125
2126 If unsure, say N.
2127
c5adae95 2128config TEST_SORT
36f33b56
DL
2129 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2130 depends on KUNIT
2131 default KUNIT_ALL_TESTS
c5adae95 2132 help
5c4e6798
GU
2133 This option enables the self-test function of 'sort()' at boot,
2134 or at module load time.
c5adae95
KF
2135
2136 If unsure, say N.
2137
5086ea4b
MR
2138config TEST_DIV64
2139 tristate "64bit/32bit division and modulo test"
2140 depends on DEBUG_KERNEL || m
2141 help
2142 Enable this to turn on 'do_div()' function test. This test is
2143 executed only once during system boot (so affects only boot time),
2144 or at module load time.
2145
2146 If unsure, say N.
2147
881c5149 2148config KPROBES_SANITY_TEST
dcbb2ee2 2149 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
881c5149
DH
2150 depends on DEBUG_KERNEL
2151 depends on KPROBES
e44e81c5 2152 depends on KUNIT
de3db3f8 2153 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
dcbb2ee2 2154 default KUNIT_ALL_TESTS
881c5149
DH
2155 help
2156 This option provides for testing basic kprobes functionality on
5a6cf77f 2157 boot. Samples of kprobe and kretprobe are inserted and
881c5149
DH
2158 verified for functionality.
2159
2160 Say N if you are unsure.
2161
f4616fab
MH
2162config FPROBE_SANITY_TEST
2163 bool "Self test for fprobe"
2164 depends on DEBUG_KERNEL
2165 depends on FPROBE
2166 depends on KUNIT=y
2167 help
2168 This option will enable testing the fprobe when the system boot.
2169 A series of tests are made to verify that the fprobe is functioning
2170 properly.
2171
2172 Say N if you are unsure.
2173
881c5149
DH
2174config BACKTRACE_SELF_TEST
2175 tristate "Self test for the backtrace code"
2176 depends on DEBUG_KERNEL
881c5149
DH
2177 help
2178 This option provides a kernel module that can be used to test
2179 the kernel stack backtrace code. This option is not useful
2180 for distributions or general kernels, but only for kernel
2181 developers working on architecture code.
2182
2183 Note that if you want to also test saved backtraces, you will
2184 have to enable STACKTRACE as well.
2185
2186 Say N if you are unsure.
2187
914a7b50
ED
2188config TEST_REF_TRACKER
2189 tristate "Self test for reference tracker"
2190 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2191 select REF_TRACKER
2192 help
2193 This option provides a kernel module performing tests
2194 using reference tracker infrastructure.
2195
2196 Say N if you are unsure.
2197
910a742d
ML
2198config RBTREE_TEST
2199 tristate "Red-Black tree test"
7c993e11 2200 depends on DEBUG_KERNEL
910a742d
ML
2201 help
2202 A benchmark measuring the performance of the rbtree library.
2203 Also includes rbtree invariant checks.
2204
4b4f3acc
FB
2205config REED_SOLOMON_TEST
2206 tristate "Reed-Solomon library test"
2207 depends on DEBUG_KERNEL || m
2208 select REED_SOLOMON
2209 select REED_SOLOMON_ENC16
2210 select REED_SOLOMON_DEC16
2211 help
2212 This option enables the self-test function of rslib at boot,
2213 or at module load time.
2214
2215 If unsure, say N.
2216
fff3fd8a
ML
2217config INTERVAL_TREE_TEST
2218 tristate "Interval tree test"
0f789b67 2219 depends on DEBUG_KERNEL
a88cc108 2220 select INTERVAL_TREE
fff3fd8a
ML
2221 help
2222 A benchmark measuring the performance of the interval tree library
2223
623fd807
GT
2224config PERCPU_TEST
2225 tristate "Per cpu operations test"
2226 depends on m && DEBUG_KERNEL
2227 help
2228 Enable this option to build test module which validates per-cpu
2229 operations.
2230
2231 If unsure, say N.
2232
881c5149 2233config ATOMIC64_SELFTEST
55ded955 2234 tristate "Perform an atomic64_t self-test"
881c5149 2235 help
55ded955
GU
2236 Enable this option to test the atomic64_t functions at boot or
2237 at module load time.
881c5149
DH
2238
2239 If unsure, say N.
2240
2241config ASYNC_RAID6_TEST
2242 tristate "Self test for hardware accelerated raid6 recovery"
2243 depends on ASYNC_RAID6_RECOV
2244 select ASYNC_MEMCPY
a7f7f624 2245 help
881c5149
DH
2246 This is a one-shot self test that permutes through the
2247 recovery of all the possible two disk failure scenarios for a
2248 N-disk array. Recovery is performed with the asynchronous
2249 raid6 recovery routines, and will optionally use an offload
2250 engine if one is available.
2251
2252 If unsure, say N.
2253
64d1d77a
AS
2254config TEST_HEXDUMP
2255 tristate "Test functions located in the hexdump module at runtime"
2256
b2ff70a0
MC
2257config STRING_SELFTEST
2258 tristate "Test string functions at runtime"
2259
881c5149
DH
2260config TEST_STRING_HELPERS
2261 tristate "Test functions located in the string_helpers module at runtime"
2262
2263config TEST_KSTRTOX
2264 tristate "Test kstrto*() family of functions at runtime"
2265
707cc728
RV
2266config TEST_PRINTF
2267 tristate "Test printf() family of functions at runtime"
2268
50f530e1
RF
2269config TEST_SCANF
2270 tristate "Test scanf() family of functions at runtime"
2271
5fd003f5
DD
2272config TEST_BITMAP
2273 tristate "Test bitmap_*() family of functions at runtime"
5fd003f5
DD
2274 help
2275 Enable this option to test the bitmap functions at boot.
2276
2277 If unsure, say N.
2278
cfaff0e5
AS
2279config TEST_UUID
2280 tristate "Test functions located in the uuid module at runtime"
2281
ad3d6c72
MW
2282config TEST_XARRAY
2283 tristate "Test the XArray code at runtime"
2284
120b1162 2285config TEST_MAPLE_TREE
845aad0a 2286 depends on DEBUG_KERNEL
120b1162
LH
2287 select DEBUG_MAPLE_TREE
2288 tristate "Test the Maple Tree code at runtime"
2289
7e1e7763 2290config TEST_RHASHTABLE
9d6dbe1b 2291 tristate "Perform selftest on resizable hash table"
7e1e7763
TG
2292 help
2293 Enable this option to test the rhashtable functions at boot.
2294
2295 If unsure, say N.
2296
8ab8ba38
MW
2297config TEST_IDA
2298 tristate "Perform selftest on IDA functions"
2299
44091d29
JP
2300config TEST_PARMAN
2301 tristate "Perform selftest on priority array manager"
44091d29
JP
2302 depends on PARMAN
2303 help
2304 Enable this option to test priority array manager on boot
2305 (or module load).
2306
2307 If unsure, say N.
2308
6aed82de
DL
2309config TEST_IRQ_TIMINGS
2310 bool "IRQ timings selftest"
2311 depends on IRQ_TIMINGS
2312 help
2313 Enable this option to test the irq timings code on boot.
2314
2315 If unsure, say N.
2316
8a6f0b47 2317config TEST_LKM
93e9ef83 2318 tristate "Test module loading with 'hello world' module"
93e9ef83
KC
2319 depends on m
2320 help
2321 This builds the "test_module" module that emits "Hello, world"
2322 on printk when loaded. It is designed to be used for basic
2323 evaluation of the module loading subsystem (for example when
2324 validating module verification). It lacks any extra dependencies,
2325 and will not normally be loaded by the system unless explicitly
2326 requested by name.
2327
2328 If unsure, say N.
2329
c348c163 2330config TEST_BITOPS
6af132f3 2331 tristate "Test module for compilation of bitops operations"
c348c163
JB
2332 depends on m
2333 help
2334 This builds the "test_bitops" module that is much like the
2335 TEST_LKM module except that it does a basic exercise of the
6af132f3
WY
2336 set/clear_bit macros and get_count_order/long to make sure there are
2337 no compiler warnings from C=1 sparse checker or -Wextra
2338 compilations. It has no dependencies and doesn't run or load unless
2339 explicitly requested by name. for example: modprobe test_bitops.
c348c163
JB
2340
2341 If unsure, say N.
2342
3f21a6b7
URS
2343config TEST_VMALLOC
2344 tristate "Test module for stress/performance analysis of vmalloc allocator"
2345 default n
2346 depends on MMU
2347 depends on m
2348 help
2349 This builds the "test_vmalloc" module that should be used for
2350 stress and performance analysis. So, any new change for vmalloc
2351 subsystem can be evaluated from performance and stability point
2352 of view.
2353
2354 If unsure, say N.
2355
3e2a4c18
KC
2356config TEST_USER_COPY
2357 tristate "Test user/kernel boundary protections"
3e2a4c18
KC
2358 depends on m
2359 help
2360 This builds the "test_user_copy" module that runs sanity checks
2361 on the copy_to/from_user infrastructure, making sure basic
2362 user/kernel boundary testing is working. If it fails to load,
2363 a regression has been detected in the user/kernel memory boundary
2364 protections.
2365
2366 If unsure, say N.
2367
64a8946b
AS
2368config TEST_BPF
2369 tristate "Test BPF filter functionality"
98920ba6 2370 depends on m && NET
64a8946b
AS
2371 help
2372 This builds the "test_bpf" module that runs various test vectors
2373 against the BPF interpreter or BPF JIT compiler depending on the
2374 current setting. This is in particular useful for BPF JIT compiler
2375 development, but also to run regression tests against changes in
3c731eba
AS
2376 the interpreter code. It also enables test stubs for eBPF maps and
2377 verifier used by user space verifier testsuite.
64a8946b
AS
2378
2379 If unsure, say N.
2380
509e56b3
MB
2381config TEST_BLACKHOLE_DEV
2382 tristate "Test blackhole netdev functionality"
2383 depends on m && NET
2384 help
2385 This builds the "test_blackhole_dev" module that validates the
2386 data path through this blackhole netdev.
2387
2388 If unsure, say N.
2389
dceeb3e7 2390config FIND_BIT_BENCHMARK
4441fca0 2391 tristate "Test find_bit functions"
4441fca0
YN
2392 help
2393 This builds the "test_find_bit" module that measure find_*_bit()
2394 functions performance.
2395
2396 If unsure, say N.
2397
0a8adf58
KC
2398config TEST_FIRMWARE
2399 tristate "Test firmware loading via userspace interface"
0a8adf58
KC
2400 depends on FW_LOADER
2401 help
2402 This builds the "test_firmware" module that creates a userspace
2403 interface for testing firmware loading. This can be used to
2404 control the triggering of firmware loading without needing an
2405 actual firmware-using device. The contents can be rechecked by
2406 userspace.
2407
2408 If unsure, say N.
2409
9308f2f9
LR
2410config TEST_SYSCTL
2411 tristate "sysctl test driver"
9308f2f9
LR
2412 depends on PROC_SYSCTL
2413 help
2414 This builds the "test_sysctl" module. This driver enables to test the
2415 proc sysctl interfaces available to drivers safely without affecting
2416 production knobs which might alter system functionality.
2417
2418 If unsure, say N.
2419
d2585f51 2420config BITFIELD_KUNIT
dcbb2ee2 2421 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
d2585f51 2422 depends on KUNIT
dcbb2ee2 2423 default KUNIT_ALL_TESTS
d2585f51
VMI
2424 help
2425 Enable this option to test the bitfield functions at boot.
2426
2427 KUnit tests run during boot and output the results to the debug log
2428 in TAP format (http://testanything.org/). Only useful for kernel devs
2429 running the KUnit test harness, and not intended for inclusion into a
2430 production build.
2431
2432 For more information on KUnit and unit tests in general please refer
2433 to the KUnit documentation in Documentation/dev-tools/kunit/.
2434
2435 If unsure, say N.
2436
0acc968f
IB
2437config HASH_KUNIT_TEST
2438 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2439 depends on KUNIT
2440 default KUNIT_ALL_TESTS
2441 help
2442 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2443 integer (<linux/hash.h>) hash functions on boot.
2444
2445 KUnit tests run during boot and output the results to the debug log
2446 in TAP format (https://testanything.org/). Only useful for kernel devs
2447 running the KUnit test harness, and not intended for inclusion into a
2448 production build.
2449
2450 For more information on KUnit and unit tests in general please refer
2451 to the KUnit documentation in Documentation/dev-tools/kunit/.
2452
2453 This is intended to help people writing architecture-specific
2454 optimized versions. If unsure, say N.
2455
5df38ca6 2456config RESOURCE_KUNIT_TEST
dcbb2ee2 2457 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
5df38ca6 2458 depends on KUNIT
dcbb2ee2 2459 default KUNIT_ALL_TESTS
5df38ca6
AS
2460 help
2461 This builds the resource API unit test.
2462 Tests the logic of API provided by resource.c and ioport.h.
2463 For more information on KUnit and unit tests in general please refer
2464 to the KUnit documentation in Documentation/dev-tools/kunit/.
2465
2466 If unsure, say N.
2467
2cb80dbb 2468config SYSCTL_KUNIT_TEST
5f215aab 2469 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2cb80dbb 2470 depends on KUNIT
5f215aab 2471 default KUNIT_ALL_TESTS
2cb80dbb
IZ
2472 help
2473 This builds the proc sysctl unit test, which runs on boot.
2474 Tests the API contract and implementation correctness of sysctl.
2475 For more information on KUnit and unit tests in general please refer
2476 to the KUnit documentation in Documentation/dev-tools/kunit/.
2477
2478 If unsure, say N.
2479
ea2dd7c0 2480config LIST_KUNIT_TEST
5f215aab 2481 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
ea2dd7c0 2482 depends on KUNIT
5f215aab 2483 default KUNIT_ALL_TESTS
ea2dd7c0
DG
2484 help
2485 This builds the linked list KUnit test suite.
2486 It tests that the API and basic functionality of the list_head type
2487 and associated macros.
2488
2489 KUnit tests run during boot and output the results to the debug log
d89775fc 2490 in TAP format (https://testanything.org/). Only useful for kernel devs
ea2dd7c0
DG
2491 running the KUnit test harness, and not intended for inclusion into a
2492 production build.
2493
2494 For more information on KUnit and unit tests in general please refer
2495 to the KUnit documentation in Documentation/dev-tools/kunit/.
2496
2497 If unsure, say N.
2498
33d599f0
MV
2499config LINEAR_RANGES_TEST
2500 tristate "KUnit test for linear_ranges"
2501 depends on KUNIT
2502 select LINEAR_RANGES
2503 help
2504 This builds the linear_ranges unit test, which runs on boot.
2505 Tests the linear_ranges logic correctness.
2506 For more information on KUnit and unit tests in general please refer
7546861a
AS
2507 to the KUnit documentation in Documentation/dev-tools/kunit/.
2508
2509 If unsure, say N.
2510
2511config CMDLINE_KUNIT_TEST
dcbb2ee2 2512 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
7546861a 2513 depends on KUNIT
dcbb2ee2 2514 default KUNIT_ALL_TESTS
7546861a
AS
2515 help
2516 This builds the cmdline API unit test.
2517 Tests the logic of API provided by cmdline.c.
2518 For more information on KUnit and unit tests in general please refer
33d599f0
MV
2519 to the KUnit documentation in Documentation/dev-tools/kunit/.
2520
2521 If unsure, say N.
2522
6d511020 2523config BITS_TEST
dcbb2ee2 2524 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
6d511020 2525 depends on KUNIT
dcbb2ee2 2526 default KUNIT_ALL_TESTS
6d511020
RF
2527 help
2528 This builds the bits unit test.
2529 Tests the logic of macros defined in bits.h.
2530 For more information on KUnit and unit tests in general please refer
2531 to the KUnit documentation in Documentation/dev-tools/kunit/.
2532
2533 If unsure, say N.
2534
1f9f78b1
OG
2535config SLUB_KUNIT_TEST
2536 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2537 depends on SLUB_DEBUG && KUNIT
2538 default KUNIT_ALL_TESTS
2539 help
2540 This builds SLUB allocator unit test.
2541 Tests SLUB cache debugging functionality.
2542 For more information on KUnit and unit tests in general please refer
2543 to the KUnit documentation in Documentation/dev-tools/kunit/.
2544
2545 If unsure, say N.
2546
b6c75c4a
TP
2547config RATIONAL_KUNIT_TEST
2548 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
8ba739ed 2549 depends on KUNIT && RATIONAL
b6c75c4a
TP
2550 default KUNIT_ALL_TESTS
2551 help
2552 This builds the rational math unit test.
2553 For more information on KUnit and unit tests in general please refer
2554 to the KUnit documentation in Documentation/dev-tools/kunit/.
2555
2556 If unsure, say N.
2557
bb95ebbe
KC
2558config MEMCPY_KUNIT_TEST
2559 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2560 depends on KUNIT
2561 default KUNIT_ALL_TESTS
2562 help
2563 Builds unit tests for memcpy(), memmove(), and memset() functions.
2564 For more information on KUnit and unit tests in general please refer
2565 to the KUnit documentation in Documentation/dev-tools/kunit/.
2566
2567 If unsure, say N.
2568
addbeea6
BVA
2569config IS_SIGNED_TYPE_KUNIT_TEST
2570 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2571 depends on KUNIT
2572 default KUNIT_ALL_TESTS
2573 help
2574 Builds unit tests for the is_signed_type() macro.
2575
2576 For more information on KUnit and unit tests in general please refer
2577 to the KUnit documentation in Documentation/dev-tools/kunit/.
2578
2579 If unsure, say N.
2580
617f55e2
KC
2581config OVERFLOW_KUNIT_TEST
2582 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2583 depends on KUNIT
2584 default KUNIT_ALL_TESTS
2585 help
2586 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2587 related functions.
2588
2589 For more information on KUnit and unit tests in general please refer
2590 to the KUnit documentation in Documentation/dev-tools/kunit/.
2591
2592 If unsure, say N.
2593
02788ebc
KC
2594config STACKINIT_KUNIT_TEST
2595 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2596 depends on KUNIT
2597 default KUNIT_ALL_TESTS
2598 help
2599 Test if the kernel is zero-initializing stack variables and
2600 padding. Coverage is controlled by compiler flags,
2601 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2602 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2603 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2604
875bfd52
KC
2605config FORTIFY_KUNIT_TEST
2606 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2607 depends on KUNIT && FORTIFY_SOURCE
2608 default KUNIT_ALL_TESTS
2609 help
2610 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2611 by the str*() and mem*() family of functions. For testing runtime
2612 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2613
724c299c
ME
2614config HW_BREAKPOINT_KUNIT_TEST
2615 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2616 depends on HAVE_HW_BREAKPOINT
2617 depends on KUNIT=y
2618 default KUNIT_ALL_TESTS
2619 help
2620 Tests for hw_breakpoint constraints accounting.
2621
2622 If unsure, say N.
2623
41eefc46
KC
2624config STRSCPY_KUNIT_TEST
2625 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2626 depends on KUNIT
2627 default KUNIT_ALL_TESTS
2628
fb3d88ab
KC
2629config SIPHASH_KUNIT_TEST
2630 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2631 depends on KUNIT
2632 default KUNIT_ALL_TESTS
2633 help
2634 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2635 functions on boot (or module load).
2636
2637 This is intended to help people writing architecture-specific
2638 optimized versions. If unsure, say N.
2639
e704f93a
DR
2640config TEST_UDELAY
2641 tristate "udelay test driver"
e704f93a
DR
2642 help
2643 This builds the "udelay_test" module that helps to make sure
2644 that udelay() is working properly.
2645
2646 If unsure, say N.
2647
2bf9e0ab
IM
2648config TEST_STATIC_KEYS
2649 tristate "Test static keys"
579e1acb
JB
2650 depends on m
2651 help
2bf9e0ab 2652 Test the static key interfaces.
579e1acb
JB
2653
2654 If unsure, say N.
2655
683263a5
JC
2656config TEST_DYNAMIC_DEBUG
2657 tristate "Test DYNAMIC_DEBUG"
2658 depends on DYNAMIC_DEBUG
2659 help
2660 This module registers a tracer callback to count enabled
2661 pr_debugs in a 'do_debugging' function, then alters their
2662 enablements, calls the function, and compares counts.
2663
2664 If unsure, say N.
2665
d9c6a72d
LR
2666config TEST_KMOD
2667 tristate "kmod stress tester"
d9c6a72d 2668 depends on m
d9c6a72d 2669 depends on NETDEVICES && NET_CORE && INET # for TUN
ae3d6a32 2670 depends on BLOCK
bbd2e05f 2671 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
d9c6a72d
LR
2672 select TEST_LKM
2673 select XFS_FS
2674 select TUN
2675 select BTRFS_FS
2676 help
2677 Test the kernel's module loading mechanism: kmod. kmod implements
2678 support to load modules using the Linux kernel's usermode helper.
2679 This test provides a series of tests against kmod.
2680
2681 Although technically you can either build test_kmod as a module or
2682 into the kernel we disallow building it into the kernel since
2683 it stress tests request_module() and this will very likely cause
2684 some issues by taking over precious threads available from other
2685 module load requests, ultimately this could be fatal.
2686
2687 To run tests run:
2688
2689 tools/testing/selftests/kmod/kmod.sh --help
2690
2691 If unsure, say N.
2692
e4dace36
FF
2693config TEST_DEBUG_VIRTUAL
2694 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2695 depends on DEBUG_VIRTUAL
2696 help
2697 Test the kernel's ability to detect incorrect calls to
2698 virt_to_phys() done against the non-linear part of the
2699 kernel's virtual address map.
2700
2701 If unsure, say N.
2702
ce76d938
AS
2703config TEST_MEMCAT_P
2704 tristate "Test memcat_p() helper function"
2705 help
2706 Test the memcat_p() helper for correctly merging two
2707 pointer arrays together.
2708
2709 If unsure, say N.
2710
a2818ee4
JL
2711config TEST_LIVEPATCH
2712 tristate "Test livepatching"
2713 default n
bae05437 2714 depends on DYNAMIC_DEBUG
a2818ee4
JL
2715 depends on LIVEPATCH
2716 depends on m
2717 help
2718 Test kernel livepatching features for correctness. The tests will
2719 load test modules that will be livepatched in various scenarios.
2720
2721 To run all the livepatching tests:
2722
2723 make -C tools/testing/selftests TARGETS=livepatch run_tests
2724
2725 Alternatively, individual tests may be invoked:
2726
2727 tools/testing/selftests/livepatch/test-callbacks.sh
2728 tools/testing/selftests/livepatch/test-livepatch.sh
2729 tools/testing/selftests/livepatch/test-shadow-vars.sh
2730
2731 If unsure, say N.
2732
0a020d41
JP
2733config TEST_OBJAGG
2734 tristate "Perform selftest on object aggreration manager"
2735 default n
2736 depends on OBJAGG
2737 help
2738 Enable this option to test object aggregation manager on boot
2739 (or module load).
2740
5015a300
AP
2741config TEST_MEMINIT
2742 tristate "Test heap/page initialization"
2743 help
2744 Test if the kernel is zero-initializing heap and page allocations.
2745 This can be useful to test init_on_alloc and init_on_free features.
2746
2747 If unsure, say N.
2748
b2ef9f5a
RC
2749config TEST_HMM
2750 tristate "Test HMM (Heterogeneous Memory Management)"
2751 depends on TRANSPARENT_HUGEPAGE
2752 depends on DEVICE_PRIVATE
2753 select HMM_MIRROR
2754 select MMU_NOTIFIER
2755 help
2756 This is a pseudo device driver solely for testing HMM.
2757 Say M here if you want to build the HMM test module.
2758 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2759
2760 If unsure, say N.
2761
e320d301
MWO
2762config TEST_FREE_PAGES
2763 tristate "Test freeing pages"
2764 help
2765 Test that a memory leak does not occur due to a race between
2766 freeing a block of pages and a speculative page reference.
2767 Loading this module is safe if your kernel has the bug fixed.
2768 If the bug is not fixed, it will leak gigabytes of memory and
2769 probably OOM your system.
2770
4185b3b9
PA
2771config TEST_FPU
2772 tristate "Test floating point operations in kernel space"
2773 depends on X86 && !KCOV_INSTRUMENT_ALL
2774 help
2775 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2776 which will trigger a sequence of floating point operations. This is used
2777 for self-testing floating point control register setting in
2778 kernel_fpu_begin().
2779
2780 If unsure, say N.
2781
1253b9b8
PM
2782config TEST_CLOCKSOURCE_WATCHDOG
2783 tristate "Test clocksource watchdog in kernel space"
2784 depends on CLOCKSOURCE_WATCHDOG
2785 help
2786 Enable this option to create a kernel module that will trigger
2787 a test of the clocksource watchdog. This module may be loaded
2788 via modprobe or insmod in which case it will run upon being
2789 loaded, or it may be built in, in which case it will run
2790 shortly after boot.
2791
2792 If unsure, say N.
2793
d3deafaa 2794endif # RUNTIME_TESTING_MENU
cc3fa840 2795
dce44566
AK
2796config ARCH_USE_MEMTEST
2797 bool
2798 help
2799 An architecture should select this when it uses early_memtest()
2800 during boot process.
2801
cc3fa840
RD
2802config MEMTEST
2803 bool "Memtest"
dce44566 2804 depends on ARCH_USE_MEMTEST
a7f7f624 2805 help
cc3fa840 2806 This option adds a kernel parameter 'memtest', which allows memtest
dce44566 2807 to be set and executed.
cc3fa840
RD
2808 memtest=0, mean disabled; -- default
2809 memtest=1, mean do 1 test pattern;
2810 ...
2811 memtest=17, mean do 17 test patterns.
2812 If you are unsure how to answer this question, answer N.
2813
21266be9 2814
06ec64b8 2815
af9ca6f9
BB
2816config HYPERV_TESTING
2817 bool "Microsoft Hyper-V driver testing"
2818 default n
2819 depends on HYPERV && DEBUG_FS
2820 help
2821 Select this option to enable Hyper-V vmbus testing.
2822
045f6d79
CD
2823endmenu # "Kernel Testing and Coverage"
2824
2f7ab126
MO
2825menu "Rust hacking"
2826
2827config RUST_DEBUG_ASSERTIONS
2828 bool "Debug assertions"
2829 depends on RUST
2830 help
2831 Enables rustc's `-Cdebug-assertions` codegen option.
2832
2833 This flag lets you turn `cfg(debug_assertions)` conditional
2834 compilation on or off. This can be used to enable extra debugging
2835 code in development but not in production. For example, it controls
2836 the behavior of the standard library's `debug_assert!` macro.
2837
2838 Note that this will apply to all Rust code, including `core`.
2839
2840 If unsure, say N.
2841
2842config RUST_OVERFLOW_CHECKS
2843 bool "Overflow checks"
2844 default y
2845 depends on RUST
2846 help
2847 Enables rustc's `-Coverflow-checks` codegen option.
2848
2849 This flag allows you to control the behavior of runtime integer
2850 overflow. When overflow-checks are enabled, a Rust panic will occur
2851 on overflow.
2852
2853 Note that this will apply to all Rust code, including `core`.
2854
2855 If unsure, say Y.
2856
ecaa6ddf
GG
2857config RUST_BUILD_ASSERT_ALLOW
2858 bool "Allow unoptimized build-time assertions"
2859 depends on RUST
2860 help
2861 Controls how are `build_error!` and `build_assert!` handled during build.
2862
2863 If calls to them exist in the binary, it may indicate a violated invariant
2864 or that the optimizer failed to verify the invariant during compilation.
2865
2866 This should not happen, thus by default the build is aborted. However,
2867 as an escape hatch, you can choose Y here to ignore them during build
2868 and let the check be carried at runtime (with `panic!` being called if
2869 the check fails).
2870
2871 If unsure, say N.
2872
2f7ab126
MO
2873endmenu # "Rust"
2874
75442fb0
MCC
2875source "Documentation/Kconfig"
2876
06ec64b8 2877endmenu # Kernel hacking