lazy tlb: allow lazy tlb mm refcounting to be configurable
[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.
5f9ae91f 391
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392config PAHOLE_HAS_LANG_EXCLUDE
393 def_bool PAHOLE_VERSION >= 124
394 help
395 Support for the --lang_exclude flag which makes pahole exclude
396 compilation units from the supplied language. Used in Kbuild to
397 omit Rust CUs which are not supported in version 1.24 of pahole,
398 otherwise it would emit malformed kernel and module binaries when
399 using DEBUG_INFO_BTF_MODULES.
400
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401config DEBUG_INFO_BTF_MODULES
402 def_bool y
403 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
404 help
405 Generate compact split BTF type information for kernel modules.
406
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407config MODULE_ALLOW_BTF_MISMATCH
408 bool "Allow loading modules with non-matching BTF type info"
409 depends on DEBUG_INFO_BTF_MODULES
410 help
411 For modules whose split BTF does not match vmlinux, load without
412 BTF rather than refusing to load. The default behavior with
413 module BTF enabled is to reject modules with such mismatches;
414 this option will still load module BTF where possible but ignore
415 it when a mismatch is found.
416
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417config GDB_SCRIPTS
418 bool "Provide GDB scripts for kernel debugging"
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419 help
420 This creates the required links to GDB helper scripts in the
421 build directory. If you load vmlinux into gdb, the helper
422 scripts will be automatically imported by gdb as well, and
423 additional functions are available to analyze a Linux kernel
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424 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
425 for further details.
3ee7b3fa 426
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427endif # DEBUG_INFO
428
35bb5b1e 429config FRAME_WARN
a83e4ca2 430 int "Warn for stack frames larger than"
35bb5b1e 431 range 0 8192
ac66998d 432 default 0 if KMSAN
0e07f663 433 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
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434 default 2048 if PARISC
435 default 1536 if (!64BIT && XTENSA)
152fe65f 436 default 1280 if KASAN && !64BIT
8d192bec 437 default 1024 if !64BIT
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438 default 2048 if 64BIT
439 help
921757bc 440 Tell the compiler to warn at build time for stack frames larger than this.
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441 Setting this too low will cause a lot of warnings.
442 Setting it to 0 disables the warning.
35bb5b1e 443
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444config STRIP_ASM_SYMS
445 bool "Strip assembler-generated symbols during link"
446 default n
447 help
448 Strip internal assembler-generated symbols during a link (symbols
449 that look like '.Lxxx') so they don't pollute the output of
450 get_wchan() and suchlike.
451
1873e870 452config READABLE_ASM
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453 bool "Generate readable assembler code"
454 depends on DEBUG_KERNEL
7d73c3e9 455 depends on CC_IS_GCC
bf4735a4 456 help
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457 Disable some compiler optimizations that tend to generate human unreadable
458 assembler output. This may make the kernel slightly slower, but it helps
459 to keep kernel developers who have to stare a lot at assembler listings
460 sane.
bf4735a4 461
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462config HEADERS_INSTALL
463 bool "Install uapi headers to usr/include"
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464 depends on !UML
465 help
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466 This option will install uapi headers (headers exported to user-space)
467 into the usr/include directory for use during the kernel build.
468 This is unneeded for building the kernel itself, but needed for some
469 user-space program samples. It is also needed by some features such
470 as uapi header sanity checks.
471
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472config DEBUG_SECTION_MISMATCH
473 bool "Enable full Section mismatch analysis"
7d73c3e9 474 depends on CC_IS_GCC
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475 help
476 The section mismatch analysis checks if there are illegal
477 references from one section to another section.
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478 During linktime or runtime, some sections are dropped;
479 any use of code/data previously in these sections would
91341d4b 480 most likely result in an oops.
e809ab01 481 In the code, functions and variables are annotated with
0db0628d 482 __init,, etc. (see the full list in include/linux/init.h),
d6fbfa4f 483 which results in the code/data being placed in specific sections.
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484 The section mismatch analysis is always performed after a full
485 kernel build, and enabling this option causes the following
b7dca6dd 486 additional step to occur:
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487 - Add the option -fno-inline-functions-called-once to gcc commands.
488 When inlining a function annotated with __init in a non-init
489 function, we would lose the section information and thus
91341d4b 490 the analysis would not catch the illegal reference.
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491 This option tells gcc to inline less (but it does result in
492 a larger kernel).
91341d4b 493
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494config SECTION_MISMATCH_WARN_ONLY
495 bool "Make section mismatch errors non-fatal"
496 default y
497 help
498 If you say N here, the build process will fail if there are any
499 section mismatch, instead of just throwing warnings.
500
501 If unsure, say Y.
502
cf536e18 503config DEBUG_FORCE_FUNCTION_ALIGN_64B
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504 bool "Force all function address 64B aligned"
505 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
d49a0626 506 select FUNCTION_ALIGNMENT_64B
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507 help
508 There are cases that a commit from one domain changes the function
509 address alignment of other domains, and cause magic performance
510 bump (regression or improvement). Enable this option will help to
511 verify if the bump is caused by function alignment changes, while
512 it will slightly increase the kernel size and affect icache usage.
513
514 It is mainly for debug and performance tuning use.
515
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516#
517# Select this config option from the architecture Kconfig, if it
518# is preferred to always offer frame pointers as a config
519# option on the architecture (regardless of KERNEL_DEBUG):
520#
521config ARCH_WANT_FRAME_POINTERS
522 bool
f346f4b3 523
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524config FRAME_POINTER
525 bool "Compile the kernel with frame pointers"
a687a533 526 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
6dfc0665 527 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
a304e1b8 528 help
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529 If you say Y here the resulting kernel image will be slightly
530 larger and slower, but it gives very useful debugging information
531 in case of kernel bugs. (precise oopses/stacktraces/warnings)
a304e1b8 532
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533config OBJTOOL
534 bool
535
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536config STACK_VALIDATION
537 bool "Compile-time stack metadata validation"
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538 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
539 select OBJTOOL
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540 default n
541 help
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542 Validate frame pointer rules at compile-time. This helps ensure that
543 runtime stack traces are more reliable.
ee9f8fce 544
b9ab5ebb 545 For more information, see
d6a21f2d 546 tools/objtool/Documentation/objtool.txt.
b9ab5ebb 547
0f620cef 548config NOINSTR_VALIDATION
6804c1af 549 bool
489e355b 550 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
03f16cd0 551 select OBJTOOL
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552 default y
553
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554config VMLINUX_MAP
555 bool "Generate vmlinux.map file when linking"
556 depends on EXPERT
557 help
558 Selecting this option will pass "-Map=vmlinux.map" to ld
559 when linking vmlinux. That file can be useful for verifying
560 and debugging magic section games, and for seeing which
561 pieces of code get eliminated with
562 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
563
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564config DEBUG_FORCE_WEAK_PER_CPU
565 bool "Force weak per-cpu definitions"
566 depends on DEBUG_KERNEL
8446f1d3 567 help
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568 s390 and alpha require percpu variables in modules to be
569 defined weak to work around addressing range issue which
570 puts the following two restrictions on percpu variable
571 definitions.
8446f1d3 572
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573 1. percpu symbols must be unique whether static or not
574 2. percpu variables can't be defined inside a function
8446f1d3 575
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576 To ensure that generic code follows the above rules, this
577 option forces all percpu variables to be defined as weak.
5f329089 578
6dfc0665 579endmenu # "Compiler options"
8446f1d3 580
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581menu "Generic Kernel Debugging Instruments"
582
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583config MAGIC_SYSRQ
584 bool "Magic SysRq key"
585 depends on !UML
586 help
587 If you say Y here, you will have some control over the system even
588 if the system crashes for example during kernel debugging (e.g., you
589 will be able to flush the buffer cache to disk, reboot the system
590 immediately or dump some status information). This is accomplished
591 by pressing various keys while holding SysRq (Alt+PrintScreen). It
592 also works on a serial console (on PC hardware at least), if you
593 send a BREAK and then within 5 seconds a command keypress. The
f8998c22
HH
594 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
595 Don't say Y unless you really know what this hack does.
8446f1d3 596
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BH
597config MAGIC_SYSRQ_DEFAULT_ENABLE
598 hex "Enable magic SysRq key functions by default"
599 depends on MAGIC_SYSRQ
600 default 0x1
601 help
602 Specifies which SysRq key functions are enabled by default.
603 This may be set to 1 or 0 to enable or disable them all, or
f8998c22 604 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
8eaede49 605
732dbf3a
FF
606config MAGIC_SYSRQ_SERIAL
607 bool "Enable magic SysRq key over serial"
608 depends on MAGIC_SYSRQ
609 default y
610 help
611 Many embedded boards have a disconnected TTL level serial which can
612 generate some garbage that can lead to spurious false sysrq detects.
613 This option allows you to decide whether you want to enable the
614 magic SysRq key.
615
68af4317
DS
616config MAGIC_SYSRQ_SERIAL_SEQUENCE
617 string "Char sequence that enables magic SysRq over serial"
618 depends on MAGIC_SYSRQ_SERIAL
619 default ""
620 help
621 Specifies a sequence of characters that can follow BREAK to enable
622 SysRq on a serial console.
623
d3394b3d
DS
624 If unsure, leave an empty string and the option will not be enabled.
625
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CD
626config DEBUG_FS
627 bool "Debug Filesystem"
628 help
629 debugfs is a virtual file system that kernel developers use to put
630 debugging files into. Enable this option to be able to read and
631 write to these files.
632
633 For detailed documentation on the debugfs API, see
634 Documentation/filesystems/.
635
636 If unsure, say N.
637
a24c6f7b
PE
638choice
639 prompt "Debugfs default access"
640 depends on DEBUG_FS
641 default DEBUG_FS_ALLOW_ALL
642 help
643 This selects the default access restrictions for debugfs.
644 It can be overridden with kernel command line option
645 debugfs=[on,no-mount,off]. The restrictions apply for API access
646 and filesystem registration.
647
648config DEBUG_FS_ALLOW_ALL
649 bool "Access normal"
650 help
651 No restrictions apply. Both API and filesystem registration
652 is on. This is the normal default operation.
653
654config DEBUG_FS_DISALLOW_MOUNT
655 bool "Do not register debugfs as filesystem"
656 help
657 The API is open but filesystem is not loaded. Clients can still do
658 their work and read with debug tools that do not need
659 debugfs filesystem.
660
661config DEBUG_FS_ALLOW_NONE
662 bool "No access"
663 help
664 Access is off. Clients get -PERM when trying to create nodes in
665 debugfs tree and debugfs is not registered as a filesystem.
666 Client can then back-off or continue without debugfs access.
667
668endchoice
669
6210b640 670source "lib/Kconfig.kgdb"
6210b640 671source "lib/Kconfig.ubsan"
2645d432 672source "lib/Kconfig.kcsan"
6210b640
CD
673
674endmenu
675
4d92b95f
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676menu "Networking Debugging"
677
678source "net/Kconfig.debug"
679
680endmenu # "Networking Debugging"
c66d7a27 681
0610c8a8 682menu "Memory Debugging"
fef2c9bc 683
8636a1f9 684source "mm/Kconfig.debug"
fef2c9bc 685
0610c8a8
DH
686config DEBUG_OBJECTS
687 bool "Debug object operations"
688 depends on DEBUG_KERNEL
9c44bc03 689 help
0610c8a8
DH
690 If you say Y here, additional code will be inserted into the
691 kernel to track the life time of various objects and validate
692 the operations on those objects.
9c44bc03 693
0610c8a8
DH
694config DEBUG_OBJECTS_SELFTEST
695 bool "Debug objects selftest"
696 depends on DEBUG_OBJECTS
697 help
698 This enables the selftest of the object debug code.
9c44bc03 699
0610c8a8
DH
700config DEBUG_OBJECTS_FREE
701 bool "Debug objects in freed memory"
702 depends on DEBUG_OBJECTS
703 help
704 This enables checks whether a k/v free operation frees an area
705 which contains an object which has not been deactivated
706 properly. This can make kmalloc/kfree-intensive workloads
707 much slower.
3ac7fe5a 708
c6f3a97f
TG
709config DEBUG_OBJECTS_TIMERS
710 bool "Debug timer objects"
711 depends on DEBUG_OBJECTS
712 help
713 If you say Y here, additional code will be inserted into the
714 timer routines to track the life time of timer objects and
715 validate the timer operations.
716
dc186ad7
TG
717config DEBUG_OBJECTS_WORK
718 bool "Debug work objects"
719 depends on DEBUG_OBJECTS
720 help
721 If you say Y here, additional code will be inserted into the
722 work queue routines to track the life time of work objects and
723 validate the work operations.
724
551d55a9
MD
725config DEBUG_OBJECTS_RCU_HEAD
726 bool "Debug RCU callbacks objects"
fc2ecf7e 727 depends on DEBUG_OBJECTS
551d55a9
MD
728 help
729 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
730
e2852ae8
TH
731config DEBUG_OBJECTS_PERCPU_COUNTER
732 bool "Debug percpu counter objects"
733 depends on DEBUG_OBJECTS
734 help
735 If you say Y here, additional code will be inserted into the
736 percpu counter routines to track the life time of percpu counter
737 objects and validate the percpu counter operations.
738
3ae70205
IM
739config DEBUG_OBJECTS_ENABLE_DEFAULT
740 int "debug_objects bootup default value (0-1)"
68d4b3df
KK
741 range 0 1
742 default "1"
743 depends on DEBUG_OBJECTS
744 help
745 Debug objects boot parameter default value
3ae70205 746
5035ebc6 747config SHRINKER_DEBUG
5035ebc6
RG
748 bool "Enable shrinker debugging support"
749 depends on DEBUG_FS
750 help
751 Say Y to enable the shrinker debugfs interface which provides
752 visibility into the kernel memory shrinkers subsystem.
753 Disable it to avoid an extra memory footprint.
754
0610c8a8
DH
755config DEBUG_STACK_USAGE
756 bool "Stack utilization instrumentation"
6c31da34 757 depends on DEBUG_KERNEL && !IA64
0610c8a8
DH
758 help
759 Enables the display of the minimum amount of free stack which each
760 task has ever had available in the sysrq-T and sysrq-P debug output.
761
762 This option will slow down process creation somewhat.
763
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CD
764config SCHED_STACK_END_CHECK
765 bool "Detect stack corruption on calls to schedule()"
766 depends on DEBUG_KERNEL
767 default n
768 help
769 This option checks for a stack overrun on calls to schedule().
770 If the stack end location is found to be over written always panic as
771 the content of the corrupted region can no longer be trusted.
772 This is to ensure no erroneous behaviour occurs which could result in
773 data corruption or a sporadic crash at a later stage once the region
774 is examined. The runtime overhead introduced is minimal.
775
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AK
776config ARCH_HAS_DEBUG_VM_PGTABLE
777 bool
778 help
779 An architecture should select this when it can successfully
780 build and run DEBUG_VM_PGTABLE.
781
a738e9ba
TG
782config DEBUG_VM_IRQSOFF
783 def_bool DEBUG_VM && !PREEMPT_RT
784
0610c8a8
DH
785config DEBUG_VM
786 bool "Debug VM"
787 depends on DEBUG_KERNEL
788 help
789 Enable this to turn on extended checks in the virtual-memory system
68d4b3df 790 that may impact performance.
0610c8a8
DH
791
792 If unsure, say N.
793
54a611b6
LH
794config DEBUG_VM_MAPLE_TREE
795 bool "Debug VM maple trees"
4f115147 796 depends on DEBUG_VM
54a611b6 797 select DEBUG_MAPLE_TREE
4f115147 798 help
54a611b6 799 Enable VM maple tree debugging information and extra validations.
4f115147
DB
800
801 If unsure, say N.
802
0610c8a8
DH
803config DEBUG_VM_RB
804 bool "Debug VM red-black trees"
805 depends on DEBUG_VM
806 help
a663dad6 807 Enable VM red-black tree debugging information and extra validations.
0610c8a8
DH
808
809 If unsure, say N.
810
95ad9755
KS
811config DEBUG_VM_PGFLAGS
812 bool "Debug page-flags operations"
813 depends on DEBUG_VM
814 help
815 Enables extra validation on page flags operations.
816
817 If unsure, say N.
818
399145f9
AK
819config DEBUG_VM_PGTABLE
820 bool "Debug arch page table for semantics compliance"
821 depends on MMU
822 depends on ARCH_HAS_DEBUG_VM_PGTABLE
823 default y if DEBUG_VM
824 help
825 This option provides a debug method which can be used to test
826 architecture page table helper functions on various platforms in
827 verifying if they comply with expected generic MM semantics. This
828 will help architecture code in making sure that any changes or
829 new additions of these helpers still conform to expected
830 semantics of the generic MM. Platforms will have to opt in for
831 this through ARCH_HAS_DEBUG_VM_PGTABLE.
832
833 If unsure, say N.
834
fa5b6ec9
LA
835config ARCH_HAS_DEBUG_VIRTUAL
836 bool
837
0610c8a8
DH
838config DEBUG_VIRTUAL
839 bool "Debug VM translations"
fa5b6ec9 840 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
0610c8a8
DH
841 help
842 Enable some costly sanity checks in virtual to page code. This can
843 catch mistakes with virt_to_page() and friends.
844
845 If unsure, say N.
846
847config DEBUG_NOMMU_REGIONS
848 bool "Debug the global anon/private NOMMU mapping region tree"
849 depends on DEBUG_KERNEL && !MMU
850 help
851 This option causes the global tree of anonymous and private mapping
852 regions to be regularly checked for invalid topology.
853
854config DEBUG_MEMORY_INIT
855 bool "Debug memory initialisation" if EXPERT
856 default !EXPERT
857 help
858 Enable this for additional checks during memory initialisation.
859 The sanity checks verify aspects of the VM such as the memory model
860 and other information provided by the architecture. Verbose
861 information will be printed at KERN_DEBUG loglevel depending
862 on the mminit_loglevel= command-line option.
863
864 If unsure, say Y
865
866config MEMORY_NOTIFIER_ERROR_INJECT
867 tristate "Memory hotplug notifier error injection module"
50f9481e 868 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
0610c8a8
DH
869 help
870 This option provides the ability to inject artificial errors to
871 memory hotplug notifier chain callbacks. It is controlled through
872 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
873
874 If the notifier call chain should be failed with some events
875 notified, write the error code to "actions/<notifier event>/error".
876
877 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
878
879 # cd /sys/kernel/debug/notifier-error-inject/memory
880 # echo -12 > actions/MEM_GOING_OFFLINE/error
881 # echo offline > /sys/devices/system/memory/memoryXXX/state
882 bash: echo: write error: Cannot allocate memory
883
884 To compile this code as a module, choose M here: the module will
885 be called memory-notifier-error-inject.
886
887 If unsure, say N.
888
889config DEBUG_PER_CPU_MAPS
890 bool "Debug access to per_cpu maps"
891 depends on DEBUG_KERNEL
892 depends on SMP
893 help
894 Say Y to verify that the per_cpu map being accessed has
895 been set up. This adds a fair amount of code to kernel memory
896 and decreases performance.
897
898 Say N if unsure.
899
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TG
900config DEBUG_KMAP_LOCAL
901 bool "Debug kmap_local temporary mappings"
902 depends on DEBUG_KERNEL && KMAP_LOCAL
903 help
904 This option enables additional error checking for the kmap_local
905 infrastructure. Disable for production use.
906
0e91a0c6
TG
907config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
908 bool
909
910config DEBUG_KMAP_LOCAL_FORCE_MAP
911 bool "Enforce kmap_local temporary mappings"
912 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
913 select KMAP_LOCAL
914 select DEBUG_KMAP_LOCAL
915 help
916 This option enforces temporary mappings through the kmap_local
917 mechanism for non-highmem pages and on non-highmem systems.
918 Disable this for production systems!
919
0610c8a8
DH
920config DEBUG_HIGHMEM
921 bool "Highmem debugging"
922 depends on DEBUG_KERNEL && HIGHMEM
0e91a0c6 923 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
6e799cb6 924 select DEBUG_KMAP_LOCAL
0610c8a8 925 help
b1357c9f
GU
926 This option enables additional error checking for high memory
927 systems. Disable for production systems.
0610c8a8
DH
928
929config HAVE_DEBUG_STACKOVERFLOW
930 bool
931
932config DEBUG_STACKOVERFLOW
933 bool "Check for stack overflows"
934 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
a7f7f624 935 help
0610c8a8 936 Say Y here if you want to check for overflows of kernel, IRQ
edb0ec07 937 and exception stacks (if your architecture uses them). This
0610c8a8
DH
938 option will show detailed messages if free stack space drops
939 below a certain limit.
940
941 These kinds of bugs usually occur when call-chains in the
942 kernel get too deep, especially when interrupts are
943 involved.
944
945 Use this in cases where you see apparently random memory
946 corruption, especially if it appears in 'struct thread_info'
947
948 If in doubt, say "N".
949
0b24becc 950source "lib/Kconfig.kasan"
0ce20dd8 951source "lib/Kconfig.kfence"
f80be457 952source "lib/Kconfig.kmsan"
0b24becc 953
0610c8a8
DH
954endmenu # "Memory Debugging"
955
a304e1b8
DW
956config DEBUG_SHIRQ
957 bool "Debug shared IRQ handlers"
0244ad00 958 depends on DEBUG_KERNEL
a304e1b8 959 help
0a2fae2a
WS
960 Enable this to generate a spurious interrupt just before a shared
961 interrupt handler is deregistered (generating one when registering
962 is currently disabled). Drivers need to handle this correctly. Some
963 don't and need to be caught.
a304e1b8 964
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CD
965menu "Debug Oops, Lockups and Hangs"
966
967config PANIC_ON_OOPS
968 bool "Panic on Oops"
969 help
970 Say Y here to enable the kernel to panic when it oopses. This
971 has the same effect as setting oops=panic on the kernel command
972 line.
973
974 This feature is useful to ensure that the kernel does not do
975 anything erroneous after an oops which could result in data
976 corruption or other issues.
977
978 Say N if unsure.
979
980config PANIC_ON_OOPS_VALUE
981 int
982 range 0 1
983 default 0 if !PANIC_ON_OOPS
984 default 1 if PANIC_ON_OOPS
985
986config PANIC_TIMEOUT
987 int "panic timeout"
988 default 0
989 help
9d5b134f 990 Set the timeout value (in seconds) until a reboot occurs when
f43a289d
CD
991 the kernel panics. If n = 0, then we wait forever. A timeout
992 value n > 0 will wait n seconds before rebooting, while a timeout
993 value n < 0 will reboot immediately.
92aef8fb 994
58687acb 995config LOCKUP_DETECTOR
05a4a952
NP
996 bool
997
998config SOFTLOCKUP_DETECTOR
999 bool "Detect Soft Lockups"
dea20a3f 1000 depends on DEBUG_KERNEL && !S390
05a4a952 1001 select LOCKUP_DETECTOR
8446f1d3 1002 help
58687acb 1003 Say Y here to enable the kernel to act as a watchdog to detect
05a4a952 1004 soft lockups.
58687acb
DZ
1005
1006 Softlockups are bugs that cause the kernel to loop in kernel
5f329089 1007 mode for more than 20 seconds, without giving other tasks a
58687acb
DZ
1008 chance to run. The current stack trace is displayed upon
1009 detection and the system will stay locked up.
8446f1d3 1010
5f00ae0d
RD
1011config BOOTPARAM_SOFTLOCKUP_PANIC
1012 bool "Panic (Reboot) On Soft Lockups"
1013 depends on SOFTLOCKUP_DETECTOR
1014 help
1015 Say Y here to enable the kernel to panic on "soft lockups",
1016 which are bugs that cause the kernel to loop in kernel
1017 mode for more than 20 seconds (configurable using the watchdog_thresh
1018 sysctl), without giving other tasks a chance to run.
1019
1020 The panic can be used in combination with panic_timeout,
1021 to cause the system to reboot automatically after a
1022 lockup has been detected. This feature is useful for
1023 high-availability systems that have uptime guarantees and
1024 where a lockup must be resolved ASAP.
1025
1026 Say N if unsure.
1027
05a4a952
NP
1028config HARDLOCKUP_DETECTOR_PERF
1029 bool
1030 select SOFTLOCKUP_DETECTOR
1031
7edaeb68
TG
1032#
1033# Enables a timestamp based low pass filter to compensate for perf based
1034# hard lockup detection which runs too fast due to turbo modes.
1035#
1036config HARDLOCKUP_CHECK_TIMESTAMP
1037 bool
1038
05a4a952
NP
1039#
1040# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1041# lockup detector rather than the perf based detector.
1042#
1043config HARDLOCKUP_DETECTOR
1044 bool "Detect Hard Lockups"
1045 depends on DEBUG_KERNEL && !S390
1046 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1047 select LOCKUP_DETECTOR
1048 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
05a4a952
NP
1049 help
1050 Say Y here to enable the kernel to act as a watchdog to detect
1051 hard lockups.
1052
58687acb 1053 Hardlockups are bugs that cause the CPU to loop in kernel mode
5f329089 1054 for more than 10 seconds, without letting other interrupts have a
58687acb
DZ
1055 chance to run. The current stack trace is displayed upon detection
1056 and the system will stay locked up.
8446f1d3 1057
fef2c9bc
DZ
1058config BOOTPARAM_HARDLOCKUP_PANIC
1059 bool "Panic (Reboot) On Hard Lockups"
8f1f66ed 1060 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
1061 help
1062 Say Y here to enable the kernel to panic on "hard lockups",
1063 which are bugs that cause the kernel to loop in kernel
5f329089
FLVC
1064 mode with interrupts disabled for more than 10 seconds (configurable
1065 using the watchdog_thresh sysctl).
fef2c9bc
DZ
1066
1067 Say N if unsure.
1068
e162b39a
MSB
1069config DETECT_HUNG_TASK
1070 bool "Detect Hung Tasks"
1071 depends on DEBUG_KERNEL
05a4a952 1072 default SOFTLOCKUP_DETECTOR
e162b39a 1073 help
0610c8a8
DH
1074 Say Y here to enable the kernel to detect "hung tasks",
1075 which are bugs that cause the task to be stuck in
96b03ab8 1076 uninterruptible "D" state indefinitely.
1da177e4 1077
0610c8a8
DH
1078 When a hung task is detected, the kernel will print the
1079 current stack trace (which you should report), but the
1080 task will stay in uninterruptible state. If lockdep is
1081 enabled then all held locks will also be reported. This
1082 feature has negligible overhead.
871751e2 1083
0610c8a8
DH
1084config DEFAULT_HUNG_TASK_TIMEOUT
1085 int "Default timeout for hung task detection (in seconds)"
1086 depends on DETECT_HUNG_TASK
1087 default 120
f0630fff 1088 help
0610c8a8
DH
1089 This option controls the default timeout (in seconds) used
1090 to determine when a task has become non-responsive and should
1091 be considered hung.
f0630fff 1092
0610c8a8
DH
1093 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1094 sysctl or by writing a value to
1095 /proc/sys/kernel/hung_task_timeout_secs.
8ff12cfc 1096
0610c8a8
DH
1097 A timeout of 0 disables the check. The default is two minutes.
1098 Keeping the default should be fine in most cases.
b69ec42b 1099
0610c8a8
DH
1100config BOOTPARAM_HUNG_TASK_PANIC
1101 bool "Panic (Reboot) On Hung Tasks"
1102 depends on DETECT_HUNG_TASK
3bba00d7 1103 help
0610c8a8
DH
1104 Say Y here to enable the kernel to panic on "hung tasks",
1105 which are bugs that cause the kernel to leave a task stuck
1106 in uninterruptible "D" state.
3bba00d7 1107
0610c8a8
DH
1108 The panic can be used in combination with panic_timeout,
1109 to cause the system to reboot automatically after a
1110 hung task has been detected. This feature is useful for
1111 high-availability systems that have uptime guarantees and
1112 where a hung tasks must be resolved ASAP.
bf96d1e3 1113
0610c8a8 1114 Say N if unsure.
bf96d1e3 1115
82607adc
TH
1116config WQ_WATCHDOG
1117 bool "Detect Workqueue Stalls"
1118 depends on DEBUG_KERNEL
1119 help
1120 Say Y here to enable stall detection on workqueues. If a
1121 worker pool doesn't make forward progress on a pending work
1122 item for over a given amount of time, 30s by default, a
1123 warning message is printed along with dump of workqueue
1124 state. This can be configured through kernel parameter
1125 "workqueue.watchdog_thresh" and its sysfs counterpart.
1126
30428ef5
KK
1127config TEST_LOCKUP
1128 tristate "Test module to generate lockups"
63646bc9 1129 depends on m
30428ef5
KK
1130 help
1131 This builds the "test_lockup" module that helps to make sure
1132 that watchdogs and lockup detectors are working properly.
1133
1134 Depending on module parameters it could emulate soft or hard
1135 lockup, "hung task", or locking arbitrary lock for a long time.
1136 Also it could generate series of lockups with cooling-down periods.
1137
1138 If unsure, say N.
1139
92aef8fb
DH
1140endmenu # "Debug lockups and hangs"
1141
ebebdd09 1142menu "Scheduler Debugging"
5800dc3c 1143
0610c8a8
DH
1144config SCHED_DEBUG
1145 bool "Collect scheduler debugging info"
35260cf5 1146 depends on DEBUG_KERNEL && DEBUG_FS
0610c8a8 1147 default y
0822ee4a 1148 help
1e90e35b 1149 If you say Y here, the /sys/kernel/debug/sched file will be provided
0610c8a8
DH
1150 that can help debug the scheduler. The runtime overhead of this
1151 option is minimal.
0822ee4a 1152
f6db8347
NR
1153config SCHED_INFO
1154 bool
1155 default n
1156
0610c8a8
DH
1157config SCHEDSTATS
1158 bool "Collect scheduler statistics"
1159 depends on DEBUG_KERNEL && PROC_FS
f6db8347 1160 select SCHED_INFO
0610c8a8
DH
1161 help
1162 If you say Y here, additional code will be inserted into the
1163 scheduler and related routines to collect statistics about
1164 scheduler behavior and provide them in /proc/schedstat. These
1165 stats may be useful for both tuning and debugging the scheduler
1166 If you aren't debugging the scheduler or trying to tune a specific
1167 application, you can say N to avoid the very slight overhead
1168 this adds.
0822ee4a 1169
ebebdd09 1170endmenu
0d9e2632 1171
3c17ad19
JS
1172config DEBUG_TIMEKEEPING
1173 bool "Enable extra timekeeping sanity checking"
1174 help
1175 This option will enable additional timekeeping sanity checks
1176 which may be helpful when diagnosing issues where timekeeping
1177 problems are suspected.
1178
1179 This may include checks in the timekeeping hotpaths, so this
1180 option may have a (very small) performance impact to some
1181 workloads.
1182
1183 If unsure, say N.
1184
1da177e4
LT
1185config DEBUG_PREEMPT
1186 bool "Debug preemptible kernel"
9f472869 1187 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1da177e4
LT
1188 help
1189 If you say Y here then the kernel will use a debug variant of the
1190 commonly used smp_processor_id() function and will print warnings
1191 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1192 will detect preemption count underflows.
1193
cc600391
HY
1194 This option has potential to introduce high runtime overhead,
1195 depending on workload as it triggers debugging routines for each
1196 this_cpu operation. It should only be used for debugging purposes.
1197
9eade16b
DH
1198menu "Lock Debugging (spinlocks, mutexes, etc...)"
1199
f07cbebb
WL
1200config LOCK_DEBUGGING_SUPPORT
1201 bool
1202 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1203 default y
1204
19193bca
WL
1205config PROVE_LOCKING
1206 bool "Lock debugging: prove locking correctness"
1207 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1208 select LOCKDEP
1209 select DEBUG_SPINLOCK
bb630f9f 1210 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca 1211 select DEBUG_RT_MUTEXES if RT_MUTEXES
c71fd893 1212 select DEBUG_RWSEMS
19193bca
WL
1213 select DEBUG_WW_MUTEX_SLOWPATH
1214 select DEBUG_LOCK_ALLOC
8fd8ad5c 1215 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
19193bca
WL
1216 select TRACE_IRQFLAGS
1217 default n
1218 help
1219 This feature enables the kernel to prove that all locking
1220 that occurs in the kernel runtime is mathematically
1221 correct: that under no circumstance could an arbitrary (and
1222 not yet triggered) combination of observed locking
1223 sequences (on an arbitrary number of CPUs, running an
1224 arbitrary number of tasks and interrupt contexts) cause a
1225 deadlock.
1226
1227 In short, this feature enables the kernel to report locking
1228 related deadlocks before they actually occur.
1229
1230 The proof does not depend on how hard and complex a
1231 deadlock scenario would be to trigger: how many
1232 participant CPUs, tasks and irq-contexts would be needed
1233 for it to trigger. The proof also does not depend on
1234 timing: if a race and a resulting deadlock is possible
1235 theoretically (no matter how unlikely the race scenario
1236 is), it will be proven so and will immediately be
1237 reported by the kernel (once the event is observed that
1238 makes the deadlock theoretically possible).
1239
1240 If a deadlock is impossible (i.e. the locking rules, as
1241 observed by the kernel, are mathematically correct), the
1242 kernel reports nothing.
1243
1244 NOTE: this feature can also be enabled for rwlocks, mutexes
1245 and rwsems - in which case all dependencies between these
1246 different locking variants are observed and mapped too, and
1247 the proof of observed correctness is also maintained for an
1248 arbitrary combination of these separate locking variants.
1249
387b1468 1250 For more details, see Documentation/locking/lockdep-design.rst.
19193bca 1251
de8f5e4f
PZ
1252config PROVE_RAW_LOCK_NESTING
1253 bool "Enable raw_spinlock - spinlock nesting checks"
1254 depends on PROVE_LOCKING
1255 default n
1256 help
1257 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1258 that the lock nesting rules for PREEMPT_RT enabled kernels are
1259 not violated.
1260
1261 NOTE: There are known nesting problems. So if you enable this
1262 option expect lockdep splats until these problems have been fully
1263 addressed which is work in progress. This config switch allows to
1264 identify and analyze these problems. It will be removed and the
9dbbc3b9 1265 check permanently enabled once the main issues have been fixed.
de8f5e4f
PZ
1266
1267 If unsure, select N.
1268
19193bca
WL
1269config LOCK_STAT
1270 bool "Lock usage statistics"
1271 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1272 select LOCKDEP
1273 select DEBUG_SPINLOCK
bb630f9f 1274 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca
WL
1275 select DEBUG_RT_MUTEXES if RT_MUTEXES
1276 select DEBUG_LOCK_ALLOC
1277 default n
1278 help
1279 This feature enables tracking lock contention points
1280
387b1468 1281 For more details, see Documentation/locking/lockstat.rst
19193bca
WL
1282
1283 This also enables lock events required by "perf lock",
1284 subcommand of perf.
1285 If you want to use "perf lock", you also need to turn on
1286 CONFIG_EVENT_TRACING.
1287
1288 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1289 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1290
e7eebaf6
IM
1291config DEBUG_RT_MUTEXES
1292 bool "RT Mutex debugging, deadlock detection"
e7eebaf6
IM
1293 depends on DEBUG_KERNEL && RT_MUTEXES
1294 help
1295 This allows rt mutex semantics violations and rt mutex related
1296 deadlocks (lockups) to be detected and reported automatically.
1297
1da177e4 1298config DEBUG_SPINLOCK
4d9f34ad 1299 bool "Spinlock and rw-lock debugging: basic checks"
1da177e4 1300 depends on DEBUG_KERNEL
e335e3eb 1301 select UNINLINE_SPIN_UNLOCK
1da177e4
LT
1302 help
1303 Say Y here and build SMP to catch missing spinlock initialization
1304 and certain other kinds of spinlock errors commonly made. This is
1305 best used in conjunction with the NMI watchdog so that spinlock
1306 deadlocks are also debuggable.
1307
4d9f34ad
IM
1308config DEBUG_MUTEXES
1309 bool "Mutex debugging: basic checks"
bb630f9f 1310 depends on DEBUG_KERNEL && !PREEMPT_RT
4d9f34ad
IM
1311 help
1312 This feature allows mutex semantics violations to be detected and
1313 reported.
1314
23010027
DV
1315config DEBUG_WW_MUTEX_SLOWPATH
1316 bool "Wait/wound mutex debugging: Slowpath testing"
f07cbebb 1317 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
23010027
DV
1318 select DEBUG_LOCK_ALLOC
1319 select DEBUG_SPINLOCK
bb630f9f
TG
1320 select DEBUG_MUTEXES if !PREEMPT_RT
1321 select DEBUG_RT_MUTEXES if PREEMPT_RT
23010027
DV
1322 help
1323 This feature enables slowpath testing for w/w mutex users by
1324 injecting additional -EDEADLK wound/backoff cases. Together with
1325 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1326 will test all possible w/w mutex interface abuse with the
1327 exception of simply not acquiring all the required locks.
4d692373
RC
1328 Note that this feature can introduce significant overhead, so
1329 it really should not be enabled in a production or distro kernel,
1330 even a debug kernel. If you are a driver writer, enable it. If
1331 you are a distro, do not.
23010027 1332
5149cbac
WL
1333config DEBUG_RWSEMS
1334 bool "RW Semaphore debugging: basic checks"
c71fd893 1335 depends on DEBUG_KERNEL
5149cbac 1336 help
c71fd893
WL
1337 This debugging feature allows mismatched rw semaphore locks
1338 and unlocks to be detected and reported.
5149cbac 1339
4d9f34ad
IM
1340config DEBUG_LOCK_ALLOC
1341 bool "Lock debugging: detect incorrect freeing of live locks"
f07cbebb 1342 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1343 select DEBUG_SPINLOCK
bb630f9f 1344 select DEBUG_MUTEXES if !PREEMPT_RT
f5694788 1345 select DEBUG_RT_MUTEXES if RT_MUTEXES
4d9f34ad
IM
1346 select LOCKDEP
1347 help
1348 This feature will check whether any held lock (spinlock, rwlock,
1349 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1350 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1351 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1352 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1353 held during task exit.
1354
4d9f34ad
IM
1355config LOCKDEP
1356 bool
f07cbebb 1357 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1358 select STACKTRACE
4d9f34ad
IM
1359 select KALLSYMS
1360 select KALLSYMS_ALL
1361
395102db
DJ
1362config LOCKDEP_SMALL
1363 bool
1364
5dc33592
TH
1365config LOCKDEP_BITS
1366 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1367 depends on LOCKDEP && !LOCKDEP_SMALL
1368 range 10 30
1369 default 15
1370 help
1371 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1372
1373config LOCKDEP_CHAINS_BITS
1374 int "Bitsize for MAX_LOCKDEP_CHAINS"
1375 depends on LOCKDEP && !LOCKDEP_SMALL
1376 range 10 30
1377 default 16
1378 help
1379 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1380
1381config LOCKDEP_STACK_TRACE_BITS
1382 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1383 depends on LOCKDEP && !LOCKDEP_SMALL
1384 range 10 30
1385 default 19
1386 help
1387 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1388
1389config LOCKDEP_STACK_TRACE_HASH_BITS
1390 int "Bitsize for STACK_TRACE_HASH_SIZE"
1391 depends on LOCKDEP && !LOCKDEP_SMALL
1392 range 10 30
1393 default 14
1394 help
f478b998 1395 Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
5dc33592
TH
1396
1397config LOCKDEP_CIRCULAR_QUEUE_BITS
1398 int "Bitsize for elements in circular_queue struct"
1399 depends on LOCKDEP
1400 range 10 30
1401 default 12
1402 help
1403 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1404
4d9f34ad
IM
1405config DEBUG_LOCKDEP
1406 bool "Lock dependency engine debugging"
517e7aa5 1407 depends on DEBUG_KERNEL && LOCKDEP
997acaf6 1408 select DEBUG_IRQFLAGS
4d9f34ad
IM
1409 help
1410 If you say Y here, the lock dependency engine will do
1411 additional runtime checks to debug itself, at the price
1412 of more runtime overhead.
1413
d902db1e
FW
1414config DEBUG_ATOMIC_SLEEP
1415 bool "Sleep inside atomic section checking"
e8f7c70f 1416 select PREEMPT_COUNT
1da177e4 1417 depends on DEBUG_KERNEL
87a4c375 1418 depends on !ARCH_NO_PREEMPT
1da177e4
LT
1419 help
1420 If you say Y here, various routines which may sleep will become very
d902db1e
FW
1421 noisy if they are called inside atomic sections: when a spinlock is
1422 held, inside an rcu read side critical section, inside preempt disabled
1423 sections, inside an interrupt, etc...
1da177e4 1424
cae2ed9a
IM
1425config DEBUG_LOCKING_API_SELFTESTS
1426 bool "Locking API boot-time self-tests"
1427 depends on DEBUG_KERNEL
1428 help
1429 Say Y here if you want the kernel to run a short self-test during
1430 bootup. The self-test checks whether common types of locking bugs
1431 are detected by debugging mechanisms or not. (if you disable
9dbbc3b9 1432 lock debugging then those bugs won't be detected of course.)
cae2ed9a
IM
1433 The following locking APIs are covered: spinlocks, rwlocks,
1434 mutexes and rwsems.
1435
0af3fe1e
PM
1436config LOCK_TORTURE_TEST
1437 tristate "torture tests for locking"
1438 depends on DEBUG_KERNEL
1439 select TORTURE_TEST
0af3fe1e
PM
1440 help
1441 This option provides a kernel module that runs torture tests
1442 on kernel locking primitives. The kernel module may be built
1443 after the fact on the running kernel to be tested, if desired.
1444
1445 Say Y here if you want kernel locking-primitive torture tests
1446 to be built into the kernel.
1447 Say M if you want these torture tests to build as a module.
1448 Say N if you are unsure.
1449
f2a5fec1
CW
1450config WW_MUTEX_SELFTEST
1451 tristate "Wait/wound mutex selftests"
1452 help
1453 This option provides a kernel module that runs tests on the
1454 on the struct ww_mutex locking API.
1455
1456 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1457 with this test harness.
1458
1459 Say M if you want these self tests to build as a module.
1460 Say N if you are unsure.
1461
e9d338a0
PM
1462config SCF_TORTURE_TEST
1463 tristate "torture tests for smp_call_function*()"
1464 depends on DEBUG_KERNEL
1465 select TORTURE_TEST
1466 help
1467 This option provides a kernel module that runs torture tests
1468 on the smp_call_function() family of primitives. The kernel
1469 module may be built after the fact on the running kernel to
1470 be tested, if desired.
1471
35feb604
PM
1472config CSD_LOCK_WAIT_DEBUG
1473 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1474 depends on DEBUG_KERNEL
1475 depends on 64BIT
1476 default n
1477 help
1478 This option enables debug prints when CPUs are slow to respond
1479 to the smp_call_function*() IPI wrappers. These debug prints
1480 include the IPI handler function currently executing (if any)
1481 and relevant stack traces.
1482
9eade16b 1483endmenu # lock debugging
8637c099 1484
9eade16b 1485config TRACE_IRQFLAGS
ed004953 1486 depends on TRACE_IRQFLAGS_SUPPORT
9eade16b 1487 bool
5ca43f6c 1488 help
9eade16b
DH
1489 Enables hooks to interrupt enabling and disabling for
1490 either tracing or lock debugging.
5ca43f6c 1491
ed004953 1492config TRACE_IRQFLAGS_NMI
1493 def_bool y
1494 depends on TRACE_IRQFLAGS
1495 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1496
1a3ea611
PM
1497config NMI_CHECK_CPU
1498 bool "Debugging for CPUs failing to respond to backtrace requests"
1499 depends on DEBUG_KERNEL
1500 depends on X86
1501 default n
1502 help
1503 Enables debug prints when a CPU fails to respond to a given
1504 backtrace NMI. These prints provide some reasons why a CPU
1505 might legitimately be failing to respond, for example, if it
1506 is offline of if ignore_nmis is set.
1507
997acaf6
MR
1508config DEBUG_IRQFLAGS
1509 bool "Debug IRQ flag manipulation"
1510 help
1511 Enables checks for potentially unsafe enabling or disabling of
1512 interrupts, such as calling raw_local_irq_restore() when interrupts
1513 are enabled.
1514
8637c099 1515config STACKTRACE
0c38e1fe 1516 bool "Stack backtrace support"
8637c099 1517 depends on STACKTRACE_SUPPORT
0c38e1fe
DJ
1518 help
1519 This option causes the kernel to create a /proc/pid/stack for
1520 every process, showing its current stack trace.
1521 It is also used by various kernel debugging features that require
1522 stack trace generation.
5ca43f6c 1523
eecabf56
TT
1524config WARN_ALL_UNSEEDED_RANDOM
1525 bool "Warn for all uses of unseeded randomness"
1526 default n
d06bfd19
JD
1527 help
1528 Some parts of the kernel contain bugs relating to their use of
1529 cryptographically secure random numbers before it's actually possible
1530 to generate those numbers securely. This setting ensures that these
1531 flaws don't go unnoticed, by enabling a message, should this ever
1532 occur. This will allow people with obscure setups to know when things
1533 are going wrong, so that they might contact developers about fixing
1534 it.
1535
eecabf56
TT
1536 Unfortunately, on some models of some architectures getting
1537 a fully seeded CRNG is extremely difficult, and so this can
1538 result in dmesg getting spammed for a surprisingly long
1539 time. This is really bad from a security perspective, and
1540 so architecture maintainers really need to do what they can
1541 to get the CRNG seeded sooner after the system is booted.
4c5d114e 1542 However, since users cannot do anything actionable to
cc1e127b 1543 address this, by default this option is disabled.
eecabf56
TT
1544
1545 Say Y here if you want to receive warnings for all uses of
1546 unseeded randomness. This will be of use primarily for
4c5d114e 1547 those developers interested in improving the security of
eecabf56
TT
1548 Linux kernels running on their architecture (or
1549 subarchitecture).
d06bfd19 1550
1da177e4
LT
1551config DEBUG_KOBJECT
1552 bool "kobject debugging"
1553 depends on DEBUG_KERNEL
1554 help
1555 If you say Y here, some extra kobject debugging messages will be sent
aca52c39 1556 to the syslog.
1da177e4 1557
c817a67e
RK
1558config DEBUG_KOBJECT_RELEASE
1559 bool "kobject release debugging"
2a999aa0 1560 depends on DEBUG_OBJECTS_TIMERS
c817a67e
RK
1561 help
1562 kobjects are reference counted objects. This means that their
1563 last reference count put is not predictable, and the kobject can
b6c69474 1564 live on past the point at which a driver decides to drop its
c817a67e
RK
1565 initial reference to the kobject gained on allocation. An
1566 example of this would be a struct device which has just been
1567 unregistered.
1568
1569 However, some buggy drivers assume that after such an operation,
1570 the memory backing the kobject can be immediately freed. This
1571 goes completely against the principles of a refcounted object.
1572
1573 If you say Y here, the kernel will delay the release of kobjects
1574 on the last reference count to improve the visibility of this
1575 kind of kobject release bug.
1576
9b2a60c4
CM
1577config HAVE_DEBUG_BUGVERBOSE
1578 bool
1579
3be5cbcd 1580menu "Debug kernel data structures"
1da177e4 1581
199a9afc
DJ
1582config DEBUG_LIST
1583 bool "Debug linked list manipulation"
4520bcb2 1584 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
199a9afc
DJ
1585 help
1586 Enable this to turn on extended checks in the linked-list
1587 walking routines.
1588
1589 If unsure, say N.
1590
8e18faea 1591config DEBUG_PLIST
b8cfff68
DS
1592 bool "Debug priority linked list manipulation"
1593 depends on DEBUG_KERNEL
1594 help
1595 Enable this to turn on extended checks in the priority-ordered
1596 linked-list (plist) walking routines. This checks the entire
1597 list multiple times during each manipulation.
1598
1599 If unsure, say N.
1600
d6ec0842
JA
1601config DEBUG_SG
1602 bool "Debug SG table operations"
1603 depends on DEBUG_KERNEL
1604 help
1605 Enable this to turn on checks on scatter-gather tables. This can
1606 help find problems with drivers that do not properly initialize
1607 their sg tables.
1608
1609 If unsure, say N.
1610
1b2439db
AV
1611config DEBUG_NOTIFIERS
1612 bool "Debug notifier call chains"
1613 depends on DEBUG_KERNEL
1614 help
1615 Enable this to turn on sanity checking for notifier call chains.
1616 This is most useful for kernel developers to make sure that
1617 modules properly unregister themselves from notifier chains.
1618 This is a relatively cheap check but if you care about maximum
1619 performance, say N.
1620
3be5cbcd
CD
1621config BUG_ON_DATA_CORRUPTION
1622 bool "Trigger a BUG when data corruption is detected"
1623 select DEBUG_LIST
1624 help
1625 Select this option if the kernel should BUG when it encounters
1626 data corruption in kernel memory structures when they get checked
1627 for validity.
1628
1629 If unsure, say N.
1630
54a611b6
LH
1631config DEBUG_MAPLE_TREE
1632 bool "Debug maple trees"
1633 depends on DEBUG_KERNEL
1634 help
1635 Enable maple tree debugging information and extra validations.
1636
1637 If unsure, say N.
1638
3be5cbcd
CD
1639endmenu
1640
e0e81739
DH
1641config DEBUG_CREDENTIALS
1642 bool "Debug credential management"
1643 depends on DEBUG_KERNEL
1644 help
1645 Enable this to turn on some debug checking for credential
1646 management. The additional code keeps track of the number of
1647 pointers from task_structs to any given cred struct, and checks to
1648 see that this number never exceeds the usage count of the cred
1649 struct.
1650
1651 Furthermore, if SELinux is enabled, this also checks that the
1652 security pointer in the cred struct is never seen to be invalid.
1653
1654 If unsure, say N.
1655
43a0a2a7 1656source "kernel/rcu/Kconfig.debug"
2f03e3ca 1657
f303fccb
TH
1658config DEBUG_WQ_FORCE_RR_CPU
1659 bool "Force round-robin CPU selection for unbound work items"
1660 depends on DEBUG_KERNEL
1661 default n
1662 help
1663 Workqueue used to implicitly guarantee that work items queued
1664 without explicit CPU specified are put on the local CPU. This
1665 guarantee is no longer true and while local CPU is still
1666 preferred work items may be put on foreign CPUs. Kernel
1667 parameter "workqueue.debug_force_rr_cpu" is added to force
1668 round-robin CPU selection to flush out usages which depend on the
1669 now broken guarantee. This config option enables the debug
1670 feature by default. When enabled, memory and cache locality will
1671 be impacted.
1672
757c989b
TG
1673config CPU_HOTPLUG_STATE_CONTROL
1674 bool "Enable CPU hotplug state control"
1675 depends on DEBUG_KERNEL
1676 depends on HOTPLUG_CPU
1677 default n
1678 help
1679 Allows to write steps between "offline" and "online" to the CPUs
1680 sysfs target file so states can be stepped granular. This is a debug
1681 option for now as the hotplug machinery cannot be stopped and
1682 restarted at arbitrary points yet.
1683
1684 Say N if your are unsure.
1685
09a74952
CD
1686config LATENCYTOP
1687 bool "Latency measuring infrastructure"
1688 depends on DEBUG_KERNEL
1689 depends on STACKTRACE_SUPPORT
1690 depends on PROC_FS
7d37cb2c 1691 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
09a74952
CD
1692 select KALLSYMS
1693 select KALLSYMS_ALL
1694 select STACKTRACE
1695 select SCHEDSTATS
09a74952
CD
1696 help
1697 Enable this option if you want to use the LatencyTOP tool
1698 to find out which userspace is blocking on what kernel operations.
1699
6ab42860
TH
1700config DEBUG_CGROUP_REF
1701 bool "Disable inlining of cgroup css reference count functions"
1702 depends on DEBUG_KERNEL
1703 depends on CGROUPS
1704 depends on KPROBES
1705 default n
1706 help
1707 Force cgroup css reference count functions to not be inlined so
1708 that they can be kprobed for debugging.
1709
09a74952
CD
1710source "kernel/trace/Kconfig"
1711
1712config PROVIDE_OHCI1394_DMA_INIT
1713 bool "Remote debugging over FireWire early on boot"
1714 depends on PCI && X86
1715 help
1716 If you want to debug problems which hang or crash the kernel early
1717 on boot and the crashing machine has a FireWire port, you can use
1718 this feature to remotely access the memory of the crashed machine
1719 over FireWire. This employs remote DMA as part of the OHCI1394
1720 specification which is now the standard for FireWire controllers.
1721
1722 With remote DMA, you can monitor the printk buffer remotely using
1723 firescope and access all memory below 4GB using fireproxy from gdb.
1724 Even controlling a kernel debugger is possible using remote DMA.
1725
1726 Usage:
1727
1728 If ohci1394_dma=early is used as boot parameter, it will initialize
1729 all OHCI1394 controllers which are found in the PCI config space.
1730
1731 As all changes to the FireWire bus such as enabling and disabling
1732 devices cause a bus reset and thereby disable remote DMA for all
1733 devices, be sure to have the cable plugged and FireWire enabled on
1734 the debugging host before booting the debug target for debugging.
1735
1736 This code (~1k) is freed after boot. By then, the firewire stack
1737 in charge of the OHCI-1394 controllers should be used instead.
1738
a74e2a22 1739 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
09a74952 1740
045f6d79
CD
1741source "samples/Kconfig"
1742
1743config ARCH_HAS_DEVMEM_IS_ALLOWED
1744 bool
1745
1746config STRICT_DEVMEM
1747 bool "Filter access to /dev/mem"
1748 depends on MMU && DEVMEM
527701ed 1749 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
045f6d79
CD
1750 default y if PPC || X86 || ARM64
1751 help
1752 If this option is disabled, you allow userspace (root) access to all
1753 of memory, including kernel and userspace memory. Accidental
1754 access to this is obviously disastrous, but specific access can
1755 be used by people debugging the kernel. Note that with PAT support
1756 enabled, even in this case there are restrictions on /dev/mem
1757 use due to the cache aliasing requirements.
1758
1759 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1760 file only allows userspace access to PCI space and the BIOS code and
1761 data regions. This is sufficient for dosemu and X and all common
1762 users of /dev/mem.
1763
1764 If in doubt, say Y.
1765
1766config IO_STRICT_DEVMEM
1767 bool "Filter I/O access to /dev/mem"
1768 depends on STRICT_DEVMEM
1769 help
1770 If this option is disabled, you allow userspace (root) access to all
1771 io-memory regardless of whether a driver is actively using that
1772 range. Accidental access to this is obviously disastrous, but
1773 specific access can be used by people debugging kernel drivers.
1774
1775 If this option is switched on, the /dev/mem file only allows
1776 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1777 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1778 if the driver using a given range cannot be disabled.
1779
1780 If in doubt, say Y.
1781
1782menu "$(SRCARCH) Debugging"
1783
1784source "arch/$(SRCARCH)/Kconfig.debug"
1785
1786endmenu
1787
1788menu "Kernel Testing and Coverage"
1789
09a74952
CD
1790source "lib/kunit/Kconfig"
1791
8d438288
AM
1792config NOTIFIER_ERROR_INJECTION
1793 tristate "Notifier error injection"
1794 depends on DEBUG_KERNEL
1795 select DEBUG_FS
1796 help
e41e85cc 1797 This option provides the ability to inject artificial errors to
8d438288
AM
1798 specified notifier chain callbacks. It is useful to test the error
1799 handling of notifier call chain failures.
1800
1801 Say N if unsure.
1802
048b9c35
AM
1803config PM_NOTIFIER_ERROR_INJECT
1804 tristate "PM notifier error injection module"
1805 depends on PM && NOTIFIER_ERROR_INJECTION
1806 default m if PM_DEBUG
1807 help
e41e85cc 1808 This option provides the ability to inject artificial errors to
048b9c35
AM
1809 PM notifier chain callbacks. It is controlled through debugfs
1810 interface /sys/kernel/debug/notifier-error-inject/pm
1811
1812 If the notifier call chain should be failed with some events
1813 notified, write the error code to "actions/<notifier event>/error".
1814
1815 Example: Inject PM suspend error (-12 = -ENOMEM)
1816
1817 # cd /sys/kernel/debug/notifier-error-inject/pm/
1818 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1819 # echo mem > /sys/power/state
1820 bash: echo: write error: Cannot allocate memory
1821
1822 To compile this code as a module, choose M here: the module will
1823 be called pm-notifier-error-inject.
1824
1825 If unsure, say N.
1826
d526e85f
BH
1827config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1828 tristate "OF reconfig notifier error injection module"
1829 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dd 1830 help
e41e85cc 1831 This option provides the ability to inject artificial errors to
d526e85f 1832 OF reconfig notifier chain callbacks. It is controlled
08dfb4dd 1833 through debugfs interface under
d526e85f 1834 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
08dfb4dd
AM
1835
1836 If the notifier call chain should be failed with some events
1837 notified, write the error code to "actions/<notifier event>/error".
1838
1839 To compile this code as a module, choose M here: the module will
e12a95f4 1840 be called of-reconfig-notifier-error-inject.
08dfb4dd
AM
1841
1842 If unsure, say N.
1843
02fff96a
NA
1844config NETDEV_NOTIFIER_ERROR_INJECT
1845 tristate "Netdev notifier error injection module"
1846 depends on NET && NOTIFIER_ERROR_INJECTION
1847 help
1848 This option provides the ability to inject artificial errors to
1849 netdevice notifier chain callbacks. It is controlled through debugfs
1850 interface /sys/kernel/debug/notifier-error-inject/netdev
1851
1852 If the notifier call chain should be failed with some events
1853 notified, write the error code to "actions/<notifier event>/error".
1854
1855 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1856
1857 # cd /sys/kernel/debug/notifier-error-inject/netdev
1858 # echo -22 > actions/NETDEV_CHANGEMTU/error
1859 # ip link set eth0 mtu 1024
1860 RTNETLINK answers: Invalid argument
1861
1862 To compile this code as a module, choose M here: the module will
1863 be called netdev-notifier-error-inject.
1864
1865 If unsure, say N.
1866
f1b4bd06 1867config FUNCTION_ERROR_INJECTION
a4412fdd 1868 bool "Fault-injections of functions"
f1b4bd06 1869 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
a4412fdd
SRG
1870 help
1871 Add fault injections into various functions that are annotated with
1872 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
ca0f2cfc 1873 value of these functions. This is useful to test error paths of code.
a4412fdd
SRG
1874
1875 If unsure, say N
f1b4bd06 1876
6ff1cb35 1877config FAULT_INJECTION
1ab8509a
AM
1878 bool "Fault-injection framework"
1879 depends on DEBUG_KERNEL
329409ae
AM
1880 help
1881 Provide fault-injection framework.
1882 For more details, see Documentation/fault-injection/.
6ff1cb35 1883
8a8b6502 1884config FAILSLAB
1ab8509a
AM
1885 bool "Fault-injection capability for kmalloc"
1886 depends on FAULT_INJECTION
773ff60e 1887 depends on SLAB || SLUB
8a8b6502 1888 help
1ab8509a 1889 Provide fault-injection capability for kmalloc.
8a8b6502 1890
933e312e 1891config FAIL_PAGE_ALLOC
29b46fa3 1892 bool "Fault-injection capability for alloc_pages()"
1ab8509a 1893 depends on FAULT_INJECTION
933e312e 1894 help
1ab8509a 1895 Provide fault-injection capability for alloc_pages().
933e312e 1896
2c739ced
AL
1897config FAULT_INJECTION_USERCOPY
1898 bool "Fault injection capability for usercopy functions"
1899 depends on FAULT_INJECTION
1900 help
1901 Provides fault-injection capability to inject failures
1902 in usercopy functions (copy_from_user(), get_user(), ...).
1903
c17bb495 1904config FAIL_MAKE_REQUEST
86327d19 1905 bool "Fault-injection capability for disk IO"
581d4e28 1906 depends on FAULT_INJECTION && BLOCK
c17bb495 1907 help
1ab8509a 1908 Provide fault-injection capability for disk IO.
c17bb495 1909
581d4e28 1910config FAIL_IO_TIMEOUT
f4d01439 1911 bool "Fault-injection capability for faking disk interrupts"
581d4e28
JA
1912 depends on FAULT_INJECTION && BLOCK
1913 help
1914 Provide fault-injection capability on end IO handling. This
1915 will make the block layer "forget" an interrupt as configured,
1916 thus exercising the error handling.
1917
1918 Only works with drivers that use the generic timeout handling,
9dbbc3b9 1919 for others it won't do anything.
581d4e28 1920
ab51fbab
DB
1921config FAIL_FUTEX
1922 bool "Fault-injection capability for futexes"
1923 select DEBUG_FS
1924 depends on FAULT_INJECTION && FUTEX
1925 help
1926 Provide fault-injection capability for futexes.
1927
f1b4bd06
MP
1928config FAULT_INJECTION_DEBUG_FS
1929 bool "Debugfs entries for fault-injection capabilities"
1930 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1931 help
1932 Enable configuration of fault-injection capabilities via debugfs.
1933
4b1a29a7
MH
1934config FAIL_FUNCTION
1935 bool "Fault-injection capability for functions"
1936 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1937 help
1938 Provide function-based fault-injection capability.
1939 This will allow you to override a specific function with a return
1940 with given return value. As a result, function caller will see
1941 an error value and have to handle it. This is useful to test the
1942 error handling in various subsystems.
1943
f1b4bd06
MP
1944config FAIL_MMC_REQUEST
1945 bool "Fault-injection capability for MMC IO"
1946 depends on FAULT_INJECTION_DEBUG_FS && MMC
6ff1cb35 1947 help
f1b4bd06
MP
1948 Provide fault-injection capability for MMC IO.
1949 This will make the mmc core return data errors. This is
1950 useful to test the error handling in the mmc block device
1951 and to test how the mmc host driver handles retries from
1952 the block device.
1df49008 1953
c782af25
CL
1954config FAIL_SUNRPC
1955 bool "Fault-injection capability for SunRPC"
1956 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1957 help
1958 Provide fault-injection capability for SunRPC and
1959 its consumers.
1960
1df49008
AM
1961config FAULT_INJECTION_STACKTRACE_FILTER
1962 bool "stacktrace filter for fault-injection capabilities"
1963 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1964 select STACKTRACE
7d37cb2c 1965 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1df49008
AM
1966 help
1967 Provide stacktrace filter for fault-injection capabilities
267c4025 1968
09a74952
CD
1969config ARCH_HAS_KCOV
1970 bool
cc3fa840 1971 help
09a74952
CD
1972 An architecture should select this when it can successfully
1973 build and run with CONFIG_KCOV. This typically requires
1974 disabling instrumentation for some early boot code.
cc3fa840 1975
09a74952
CD
1976config CC_HAS_SANCOV_TRACE_PC
1977 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
cc3fa840 1978
cc3fa840 1979
09a74952
CD
1980config KCOV
1981 bool "Code coverage for fuzzing"
1982 depends on ARCH_HAS_KCOV
1983 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
22102f45 1984 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
bece04b5 1985 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
09a74952
CD
1986 select DEBUG_FS
1987 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
22102f45 1988 select OBJTOOL if HAVE_NOINSTR_HACK
09a74952
CD
1989 help
1990 KCOV exposes kernel code coverage information in a form suitable
1991 for coverage-guided fuzzing (randomized testing).
cc3fa840 1992
09a74952
CD
1993 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1994 different machines and across reboots. If you need stable PC values,
1995 disable RANDOMIZE_BASE.
cc3fa840 1996
09a74952 1997 For more details, see Documentation/dev-tools/kcov.rst.
cc3fa840 1998
09a74952
CD
1999config KCOV_ENABLE_COMPARISONS
2000 bool "Enable comparison operands collection by KCOV"
2001 depends on KCOV
2002 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2003 help
2004 KCOV also exposes operands of every comparison in the instrumented
2005 code along with operand sizes and PCs of the comparison instructions.
2006 These operands can be used by fuzzing engines to improve the quality
2007 of fuzzing coverage.
cc3fa840 2008
09a74952
CD
2009config KCOV_INSTRUMENT_ALL
2010 bool "Instrument all code by default"
2011 depends on KCOV
2012 default y
2013 help
2014 If you are doing generic system call fuzzing (like e.g. syzkaller),
2015 then you will want to instrument the whole kernel and you should
2016 say y here. If you are doing more targeted fuzzing (like e.g.
2017 filesystem fuzzing with AFL) then you will want to enable coverage
2018 for more specific subsets of files, and should say n here.
84bc809e 2019
5ff3b30a
AK
2020config KCOV_IRQ_AREA_SIZE
2021 hex "Size of interrupt coverage collection area in words"
2022 depends on KCOV
2023 default 0x40000
2024 help
2025 KCOV uses preallocated per-cpu areas to collect coverage from
2026 soft interrupts. This specifies the size of those areas in the
2027 number of unsigned long words.
2028
d3deafaa
VL
2029menuconfig RUNTIME_TESTING_MENU
2030 bool "Runtime Testing"
908009e8 2031 def_bool y
d3deafaa
VL
2032
2033if RUNTIME_TESTING_MENU
881c5149 2034
d5528cc1
GU
2035config TEST_DHRY
2036 tristate "Dhrystone benchmark test"
2037 help
2038 Enable this to include the Dhrystone 2.1 benchmark. This test
2039 calculates the number of Dhrystones per second, and the number of
2040 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2041 by 1757 (the number of Dhrystones per second obtained on the VAX
2042 11/780, nominally a 1 MIPS machine).
2043
2044 To run the benchmark, it needs to be enabled explicitly, either from
2045 the kernel command line (when built-in), or from userspace (when
2046 built-in or modular.
2047
2048 Run once during kernel boot:
2049
2050 test_dhry.run
2051
2052 Set number of iterations from kernel command line:
2053
2054 test_dhry.iterations=<n>
2055
2056 Set number of iterations from userspace:
2057
2058 echo <n> > /sys/module/test_dhry/parameters/iterations
2059
2060 Trigger manual run from userspace:
2061
2062 echo y > /sys/module/test_dhry/parameters/run
2063
2064 If the number of iterations is <= 0, the test will devise a suitable
2065 number of iterations (test runs for at least 2s) automatically.
2066 This process takes ca. 4s.
2067
2068 If unsure, say N.
2069
881c5149
DH
2070config LKDTM
2071 tristate "Linux Kernel Dump Test Tool Module"
2072 depends on DEBUG_FS
881c5149
DH
2073 help
2074 This module enables testing of the different dumping mechanisms by
2075 inducing system failures at predefined crash points.
2076 If you don't need it: say N
2077 Choose M here to compile this code as a module. The module will be
2078 called lkdtm.
2079
2080 Documentation on how to use the module can be found in
10ffebbe 2081 Documentation/fault-injection/provoke-crashes.rst
881c5149 2082
d3c0ca49
SV
2083config CPUMASK_KUNIT_TEST
2084 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
c41e8866
SV
2085 depends on KUNIT
2086 default KUNIT_ALL_TESTS
2087 help
2088 Enable to turn on cpumask tests, running at boot or module load time.
2089
d3c0ca49
SV
2090 For more information on KUnit and unit tests in general, please refer
2091 to the KUnit documentation in Documentation/dev-tools/kunit/.
2092
c41e8866
SV
2093 If unsure, say N.
2094
881c5149 2095config TEST_LIST_SORT
ebd09577
DL
2096 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2097 depends on KUNIT
2098 default KUNIT_ALL_TESTS
881c5149
DH
2099 help
2100 Enable this to turn on 'list_sort()' function test. This test is
e327fd7c
GU
2101 executed only once during system boot (so affects only boot time),
2102 or at module load time.
881c5149
DH
2103
2104 If unsure, say N.
2105
6e24628d
IR
2106config TEST_MIN_HEAP
2107 tristate "Min heap test"
2108 depends on DEBUG_KERNEL || m
2109 help
2110 Enable this to turn on min heap function tests. This test is
2111 executed only once during system boot (so affects only boot time),
2112 or at module load time.
2113
2114 If unsure, say N.
2115
c5adae95 2116config TEST_SORT
36f33b56
DL
2117 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2118 depends on KUNIT
2119 default KUNIT_ALL_TESTS
c5adae95 2120 help
5c4e6798
GU
2121 This option enables the self-test function of 'sort()' at boot,
2122 or at module load time.
c5adae95
KF
2123
2124 If unsure, say N.
2125
5086ea4b
MR
2126config TEST_DIV64
2127 tristate "64bit/32bit division and modulo test"
2128 depends on DEBUG_KERNEL || m
2129 help
2130 Enable this to turn on 'do_div()' function test. This test is
2131 executed only once during system boot (so affects only boot time),
2132 or at module load time.
2133
2134 If unsure, say N.
2135
881c5149 2136config KPROBES_SANITY_TEST
dcbb2ee2 2137 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
881c5149
DH
2138 depends on DEBUG_KERNEL
2139 depends on KPROBES
e44e81c5 2140 depends on KUNIT
de3db3f8 2141 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
dcbb2ee2 2142 default KUNIT_ALL_TESTS
881c5149
DH
2143 help
2144 This option provides for testing basic kprobes functionality on
5a6cf77f 2145 boot. Samples of kprobe and kretprobe are inserted and
881c5149
DH
2146 verified for functionality.
2147
2148 Say N if you are unsure.
2149
f4616fab
MH
2150config FPROBE_SANITY_TEST
2151 bool "Self test for fprobe"
2152 depends on DEBUG_KERNEL
2153 depends on FPROBE
2154 depends on KUNIT=y
2155 help
2156 This option will enable testing the fprobe when the system boot.
2157 A series of tests are made to verify that the fprobe is functioning
2158 properly.
2159
2160 Say N if you are unsure.
2161
881c5149
DH
2162config BACKTRACE_SELF_TEST
2163 tristate "Self test for the backtrace code"
2164 depends on DEBUG_KERNEL
881c5149
DH
2165 help
2166 This option provides a kernel module that can be used to test
2167 the kernel stack backtrace code. This option is not useful
2168 for distributions or general kernels, but only for kernel
2169 developers working on architecture code.
2170
2171 Note that if you want to also test saved backtraces, you will
2172 have to enable STACKTRACE as well.
2173
2174 Say N if you are unsure.
2175
914a7b50
ED
2176config TEST_REF_TRACKER
2177 tristate "Self test for reference tracker"
2178 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2179 select REF_TRACKER
2180 help
2181 This option provides a kernel module performing tests
2182 using reference tracker infrastructure.
2183
2184 Say N if you are unsure.
2185
910a742d
ML
2186config RBTREE_TEST
2187 tristate "Red-Black tree test"
7c993e11 2188 depends on DEBUG_KERNEL
910a742d
ML
2189 help
2190 A benchmark measuring the performance of the rbtree library.
2191 Also includes rbtree invariant checks.
2192
4b4f3acc
FB
2193config REED_SOLOMON_TEST
2194 tristate "Reed-Solomon library test"
2195 depends on DEBUG_KERNEL || m
2196 select REED_SOLOMON
2197 select REED_SOLOMON_ENC16
2198 select REED_SOLOMON_DEC16
2199 help
2200 This option enables the self-test function of rslib at boot,
2201 or at module load time.
2202
2203 If unsure, say N.
2204
fff3fd8a
ML
2205config INTERVAL_TREE_TEST
2206 tristate "Interval tree test"
0f789b67 2207 depends on DEBUG_KERNEL
a88cc108 2208 select INTERVAL_TREE
fff3fd8a
ML
2209 help
2210 A benchmark measuring the performance of the interval tree library
2211
623fd807
GT
2212config PERCPU_TEST
2213 tristate "Per cpu operations test"
2214 depends on m && DEBUG_KERNEL
2215 help
2216 Enable this option to build test module which validates per-cpu
2217 operations.
2218
2219 If unsure, say N.
2220
881c5149 2221config ATOMIC64_SELFTEST
55ded955 2222 tristate "Perform an atomic64_t self-test"
881c5149 2223 help
55ded955
GU
2224 Enable this option to test the atomic64_t functions at boot or
2225 at module load time.
881c5149
DH
2226
2227 If unsure, say N.
2228
2229config ASYNC_RAID6_TEST
2230 tristate "Self test for hardware accelerated raid6 recovery"
2231 depends on ASYNC_RAID6_RECOV
2232 select ASYNC_MEMCPY
a7f7f624 2233 help
881c5149
DH
2234 This is a one-shot self test that permutes through the
2235 recovery of all the possible two disk failure scenarios for a
2236 N-disk array. Recovery is performed with the asynchronous
2237 raid6 recovery routines, and will optionally use an offload
2238 engine if one is available.
2239
2240 If unsure, say N.
2241
64d1d77a
AS
2242config TEST_HEXDUMP
2243 tristate "Test functions located in the hexdump module at runtime"
2244
b2ff70a0
MC
2245config STRING_SELFTEST
2246 tristate "Test string functions at runtime"
2247
881c5149
DH
2248config TEST_STRING_HELPERS
2249 tristate "Test functions located in the string_helpers module at runtime"
2250
2251config TEST_KSTRTOX
2252 tristate "Test kstrto*() family of functions at runtime"
2253
707cc728
RV
2254config TEST_PRINTF
2255 tristate "Test printf() family of functions at runtime"
2256
50f530e1
RF
2257config TEST_SCANF
2258 tristate "Test scanf() family of functions at runtime"
2259
5fd003f5
DD
2260config TEST_BITMAP
2261 tristate "Test bitmap_*() family of functions at runtime"
5fd003f5
DD
2262 help
2263 Enable this option to test the bitmap functions at boot.
2264
2265 If unsure, say N.
2266
cfaff0e5
AS
2267config TEST_UUID
2268 tristate "Test functions located in the uuid module at runtime"
2269
ad3d6c72
MW
2270config TEST_XARRAY
2271 tristate "Test the XArray code at runtime"
2272
120b1162 2273config TEST_MAPLE_TREE
845aad0a 2274 depends on DEBUG_KERNEL
120b1162
LH
2275 select DEBUG_MAPLE_TREE
2276 tristate "Test the Maple Tree code at runtime"
2277
7e1e7763 2278config TEST_RHASHTABLE
9d6dbe1b 2279 tristate "Perform selftest on resizable hash table"
7e1e7763
TG
2280 help
2281 Enable this option to test the rhashtable functions at boot.
2282
2283 If unsure, say N.
2284
8ab8ba38
MW
2285config TEST_IDA
2286 tristate "Perform selftest on IDA functions"
2287
44091d29
JP
2288config TEST_PARMAN
2289 tristate "Perform selftest on priority array manager"
44091d29
JP
2290 depends on PARMAN
2291 help
2292 Enable this option to test priority array manager on boot
2293 (or module load).
2294
2295 If unsure, say N.
2296
6aed82de
DL
2297config TEST_IRQ_TIMINGS
2298 bool "IRQ timings selftest"
2299 depends on IRQ_TIMINGS
2300 help
2301 Enable this option to test the irq timings code on boot.
2302
2303 If unsure, say N.
2304
8a6f0b47 2305config TEST_LKM
93e9ef83 2306 tristate "Test module loading with 'hello world' module"
93e9ef83
KC
2307 depends on m
2308 help
2309 This builds the "test_module" module that emits "Hello, world"
2310 on printk when loaded. It is designed to be used for basic
2311 evaluation of the module loading subsystem (for example when
2312 validating module verification). It lacks any extra dependencies,
2313 and will not normally be loaded by the system unless explicitly
2314 requested by name.
2315
2316 If unsure, say N.
2317
c348c163 2318config TEST_BITOPS
6af132f3 2319 tristate "Test module for compilation of bitops operations"
c348c163
JB
2320 depends on m
2321 help
2322 This builds the "test_bitops" module that is much like the
2323 TEST_LKM module except that it does a basic exercise of the
6af132f3
WY
2324 set/clear_bit macros and get_count_order/long to make sure there are
2325 no compiler warnings from C=1 sparse checker or -Wextra
2326 compilations. It has no dependencies and doesn't run or load unless
2327 explicitly requested by name. for example: modprobe test_bitops.
c348c163
JB
2328
2329 If unsure, say N.
2330
3f21a6b7
URS
2331config TEST_VMALLOC
2332 tristate "Test module for stress/performance analysis of vmalloc allocator"
2333 default n
2334 depends on MMU
2335 depends on m
2336 help
2337 This builds the "test_vmalloc" module that should be used for
2338 stress and performance analysis. So, any new change for vmalloc
2339 subsystem can be evaluated from performance and stability point
2340 of view.
2341
2342 If unsure, say N.
2343
3e2a4c18
KC
2344config TEST_USER_COPY
2345 tristate "Test user/kernel boundary protections"
3e2a4c18
KC
2346 depends on m
2347 help
2348 This builds the "test_user_copy" module that runs sanity checks
2349 on the copy_to/from_user infrastructure, making sure basic
2350 user/kernel boundary testing is working. If it fails to load,
2351 a regression has been detected in the user/kernel memory boundary
2352 protections.
2353
2354 If unsure, say N.
2355
64a8946b
AS
2356config TEST_BPF
2357 tristate "Test BPF filter functionality"
98920ba6 2358 depends on m && NET
64a8946b
AS
2359 help
2360 This builds the "test_bpf" module that runs various test vectors
2361 against the BPF interpreter or BPF JIT compiler depending on the
2362 current setting. This is in particular useful for BPF JIT compiler
2363 development, but also to run regression tests against changes in
3c731eba
AS
2364 the interpreter code. It also enables test stubs for eBPF maps and
2365 verifier used by user space verifier testsuite.
64a8946b
AS
2366
2367 If unsure, say N.
2368
509e56b3
MB
2369config TEST_BLACKHOLE_DEV
2370 tristate "Test blackhole netdev functionality"
2371 depends on m && NET
2372 help
2373 This builds the "test_blackhole_dev" module that validates the
2374 data path through this blackhole netdev.
2375
2376 If unsure, say N.
2377
dceeb3e7 2378config FIND_BIT_BENCHMARK
4441fca0 2379 tristate "Test find_bit functions"
4441fca0
YN
2380 help
2381 This builds the "test_find_bit" module that measure find_*_bit()
2382 functions performance.
2383
2384 If unsure, say N.
2385
0a8adf58
KC
2386config TEST_FIRMWARE
2387 tristate "Test firmware loading via userspace interface"
0a8adf58
KC
2388 depends on FW_LOADER
2389 help
2390 This builds the "test_firmware" module that creates a userspace
2391 interface for testing firmware loading. This can be used to
2392 control the triggering of firmware loading without needing an
2393 actual firmware-using device. The contents can be rechecked by
2394 userspace.
2395
2396 If unsure, say N.
2397
9308f2f9
LR
2398config TEST_SYSCTL
2399 tristate "sysctl test driver"
9308f2f9
LR
2400 depends on PROC_SYSCTL
2401 help
2402 This builds the "test_sysctl" module. This driver enables to test the
2403 proc sysctl interfaces available to drivers safely without affecting
2404 production knobs which might alter system functionality.
2405
2406 If unsure, say N.
2407
d2585f51 2408config BITFIELD_KUNIT
dcbb2ee2 2409 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
d2585f51 2410 depends on KUNIT
dcbb2ee2 2411 default KUNIT_ALL_TESTS
d2585f51
VMI
2412 help
2413 Enable this option to test the bitfield functions at boot.
2414
2415 KUnit tests run during boot and output the results to the debug log
2416 in TAP format (http://testanything.org/). Only useful for kernel devs
2417 running the KUnit test harness, and not intended for inclusion into a
2418 production build.
2419
2420 For more information on KUnit and unit tests in general please refer
2421 to the KUnit documentation in Documentation/dev-tools/kunit/.
2422
2423 If unsure, say N.
2424
0acc968f
IB
2425config HASH_KUNIT_TEST
2426 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2427 depends on KUNIT
2428 default KUNIT_ALL_TESTS
2429 help
2430 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2431 integer (<linux/hash.h>) hash functions on boot.
2432
2433 KUnit tests run during boot and output the results to the debug log
2434 in TAP format (https://testanything.org/). Only useful for kernel devs
2435 running the KUnit test harness, and not intended for inclusion into a
2436 production build.
2437
2438 For more information on KUnit and unit tests in general please refer
2439 to the KUnit documentation in Documentation/dev-tools/kunit/.
2440
2441 This is intended to help people writing architecture-specific
2442 optimized versions. If unsure, say N.
2443
5df38ca6 2444config RESOURCE_KUNIT_TEST
dcbb2ee2 2445 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
5df38ca6 2446 depends on KUNIT
dcbb2ee2 2447 default KUNIT_ALL_TESTS
5df38ca6
AS
2448 help
2449 This builds the resource API unit test.
2450 Tests the logic of API provided by resource.c and ioport.h.
2451 For more information on KUnit and unit tests in general please refer
2452 to the KUnit documentation in Documentation/dev-tools/kunit/.
2453
2454 If unsure, say N.
2455
2cb80dbb 2456config SYSCTL_KUNIT_TEST
5f215aab 2457 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2cb80dbb 2458 depends on KUNIT
5f215aab 2459 default KUNIT_ALL_TESTS
2cb80dbb
IZ
2460 help
2461 This builds the proc sysctl unit test, which runs on boot.
2462 Tests the API contract and implementation correctness of sysctl.
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
ea2dd7c0 2468config LIST_KUNIT_TEST
5f215aab 2469 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
ea2dd7c0 2470 depends on KUNIT
5f215aab 2471 default KUNIT_ALL_TESTS
ea2dd7c0
DG
2472 help
2473 This builds the linked list KUnit test suite.
2474 It tests that the API and basic functionality of the list_head type
2475 and associated macros.
2476
2477 KUnit tests run during boot and output the results to the debug log
d89775fc 2478 in TAP format (https://testanything.org/). Only useful for kernel devs
ea2dd7c0
DG
2479 running the KUnit test harness, and not intended for inclusion into a
2480 production build.
2481
2482 For more information on KUnit and unit tests in general please refer
2483 to the KUnit documentation in Documentation/dev-tools/kunit/.
2484
2485 If unsure, say N.
2486
789538c6
RM
2487config HASHTABLE_KUNIT_TEST
2488 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2489 depends on KUNIT
2490 default KUNIT_ALL_TESTS
2491 help
2492 This builds the hashtable KUnit test suite.
2493 It tests the basic functionality of the API defined in
2494 include/linux/hashtable.h. For more information on KUnit and
2495 unit tests in general please refer to the KUnit documentation
2496 in Documentation/dev-tools/kunit/.
2497
2498 If unsure, say N.
2499
33d599f0
MV
2500config LINEAR_RANGES_TEST
2501 tristate "KUnit test for linear_ranges"
2502 depends on KUNIT
2503 select LINEAR_RANGES
2504 help
2505 This builds the linear_ranges unit test, which runs on boot.
2506 Tests the linear_ranges logic correctness.
2507 For more information on KUnit and unit tests in general please refer
7546861a
AS
2508 to the KUnit documentation in Documentation/dev-tools/kunit/.
2509
2510 If unsure, say N.
2511
2512config CMDLINE_KUNIT_TEST
dcbb2ee2 2513 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
7546861a 2514 depends on KUNIT
dcbb2ee2 2515 default KUNIT_ALL_TESTS
7546861a
AS
2516 help
2517 This builds the cmdline API unit test.
2518 Tests the logic of API provided by cmdline.c.
2519 For more information on KUnit and unit tests in general please refer
33d599f0
MV
2520 to the KUnit documentation in Documentation/dev-tools/kunit/.
2521
2522 If unsure, say N.
2523
6d511020 2524config BITS_TEST
dcbb2ee2 2525 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
6d511020 2526 depends on KUNIT
dcbb2ee2 2527 default KUNIT_ALL_TESTS
6d511020
RF
2528 help
2529 This builds the bits unit test.
2530 Tests the logic of macros defined in bits.h.
2531 For more information on KUnit and unit tests in general please refer
2532 to the KUnit documentation in Documentation/dev-tools/kunit/.
2533
2534 If unsure, say N.
2535
1f9f78b1
OG
2536config SLUB_KUNIT_TEST
2537 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2538 depends on SLUB_DEBUG && KUNIT
2539 default KUNIT_ALL_TESTS
2540 help
2541 This builds SLUB allocator unit test.
2542 Tests SLUB cache debugging functionality.
2543 For more information on KUnit and unit tests in general please refer
2544 to the KUnit documentation in Documentation/dev-tools/kunit/.
2545
2546 If unsure, say N.
2547
b6c75c4a
TP
2548config RATIONAL_KUNIT_TEST
2549 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
8ba739ed 2550 depends on KUNIT && RATIONAL
b6c75c4a
TP
2551 default KUNIT_ALL_TESTS
2552 help
2553 This builds the rational math unit test.
2554 For more information on KUnit and unit tests in general please refer
2555 to the KUnit documentation in Documentation/dev-tools/kunit/.
2556
2557 If unsure, say N.
2558
bb95ebbe
KC
2559config MEMCPY_KUNIT_TEST
2560 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2561 depends on KUNIT
2562 default KUNIT_ALL_TESTS
2563 help
2564 Builds unit tests for memcpy(), memmove(), and memset() functions.
2565 For more information on KUnit and unit tests in general please refer
2566 to the KUnit documentation in Documentation/dev-tools/kunit/.
2567
2568 If unsure, say N.
2569
4acf1de3
KC
2570config MEMCPY_SLOW_KUNIT_TEST
2571 bool "Include exhaustive memcpy tests"
2572 depends on MEMCPY_KUNIT_TEST
2573 default y
2574 help
2575 Some memcpy tests are quite exhaustive in checking for overlaps
2576 and bit ranges. These can be very slow, so they are split out
2577 as a separate config, in case they need to be disabled.
2578
addbeea6
BVA
2579config IS_SIGNED_TYPE_KUNIT_TEST
2580 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2581 depends on KUNIT
2582 default KUNIT_ALL_TESTS
2583 help
2584 Builds unit tests for the is_signed_type() macro.
2585
2586 For more information on KUnit and unit tests in general please refer
2587 to the KUnit documentation in Documentation/dev-tools/kunit/.
2588
2589 If unsure, say N.
2590
617f55e2
KC
2591config OVERFLOW_KUNIT_TEST
2592 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2593 depends on KUNIT
2594 default KUNIT_ALL_TESTS
2595 help
2596 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2597 related functions.
2598
2599 For more information on KUnit and unit tests in general please refer
2600 to the KUnit documentation in Documentation/dev-tools/kunit/.
2601
2602 If unsure, say N.
2603
02788ebc
KC
2604config STACKINIT_KUNIT_TEST
2605 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2606 depends on KUNIT
2607 default KUNIT_ALL_TESTS
2608 help
2609 Test if the kernel is zero-initializing stack variables and
2610 padding. Coverage is controlled by compiler flags,
2611 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2612 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2613 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2614
875bfd52
KC
2615config FORTIFY_KUNIT_TEST
2616 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2617 depends on KUNIT && FORTIFY_SOURCE
2618 default KUNIT_ALL_TESTS
2619 help
2620 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2621 by the str*() and mem*() family of functions. For testing runtime
2622 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2623
724c299c
ME
2624config HW_BREAKPOINT_KUNIT_TEST
2625 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2626 depends on HAVE_HW_BREAKPOINT
2627 depends on KUNIT=y
2628 default KUNIT_ALL_TESTS
2629 help
2630 Tests for hw_breakpoint constraints accounting.
2631
2632 If unsure, say N.
2633
41eefc46
KC
2634config STRSCPY_KUNIT_TEST
2635 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2636 depends on KUNIT
2637 default KUNIT_ALL_TESTS
2638
fb3d88ab
KC
2639config SIPHASH_KUNIT_TEST
2640 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2641 depends on KUNIT
2642 default KUNIT_ALL_TESTS
2643 help
2644 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2645 functions on boot (or module load).
2646
2647 This is intended to help people writing architecture-specific
2648 optimized versions. If unsure, say N.
2649
e704f93a
DR
2650config TEST_UDELAY
2651 tristate "udelay test driver"
e704f93a
DR
2652 help
2653 This builds the "udelay_test" module that helps to make sure
2654 that udelay() is working properly.
2655
2656 If unsure, say N.
2657
2bf9e0ab
IM
2658config TEST_STATIC_KEYS
2659 tristate "Test static keys"
579e1acb
JB
2660 depends on m
2661 help
2bf9e0ab 2662 Test the static key interfaces.
579e1acb
JB
2663
2664 If unsure, say N.
2665
683263a5
JC
2666config TEST_DYNAMIC_DEBUG
2667 tristate "Test DYNAMIC_DEBUG"
2668 depends on DYNAMIC_DEBUG
2669 help
2670 This module registers a tracer callback to count enabled
2671 pr_debugs in a 'do_debugging' function, then alters their
2672 enablements, calls the function, and compares counts.
2673
2674 If unsure, say N.
2675
d9c6a72d
LR
2676config TEST_KMOD
2677 tristate "kmod stress tester"
d9c6a72d 2678 depends on m
d9c6a72d 2679 depends on NETDEVICES && NET_CORE && INET # for TUN
ae3d6a32 2680 depends on BLOCK
bbd2e05f 2681 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
d9c6a72d
LR
2682 select TEST_LKM
2683 select XFS_FS
2684 select TUN
2685 select BTRFS_FS
2686 help
2687 Test the kernel's module loading mechanism: kmod. kmod implements
2688 support to load modules using the Linux kernel's usermode helper.
2689 This test provides a series of tests against kmod.
2690
2691 Although technically you can either build test_kmod as a module or
2692 into the kernel we disallow building it into the kernel since
2693 it stress tests request_module() and this will very likely cause
2694 some issues by taking over precious threads available from other
2695 module load requests, ultimately this could be fatal.
2696
2697 To run tests run:
2698
2699 tools/testing/selftests/kmod/kmod.sh --help
2700
2701 If unsure, say N.
2702
e4dace36
FF
2703config TEST_DEBUG_VIRTUAL
2704 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2705 depends on DEBUG_VIRTUAL
2706 help
2707 Test the kernel's ability to detect incorrect calls to
2708 virt_to_phys() done against the non-linear part of the
2709 kernel's virtual address map.
2710
2711 If unsure, say N.
2712
ce76d938
AS
2713config TEST_MEMCAT_P
2714 tristate "Test memcat_p() helper function"
2715 help
2716 Test the memcat_p() helper for correctly merging two
2717 pointer arrays together.
2718
2719 If unsure, say N.
2720
a2818ee4
JL
2721config TEST_LIVEPATCH
2722 tristate "Test livepatching"
2723 default n
bae05437 2724 depends on DYNAMIC_DEBUG
a2818ee4
JL
2725 depends on LIVEPATCH
2726 depends on m
2727 help
2728 Test kernel livepatching features for correctness. The tests will
2729 load test modules that will be livepatched in various scenarios.
2730
2731 To run all the livepatching tests:
2732
2733 make -C tools/testing/selftests TARGETS=livepatch run_tests
2734
2735 Alternatively, individual tests may be invoked:
2736
2737 tools/testing/selftests/livepatch/test-callbacks.sh
2738 tools/testing/selftests/livepatch/test-livepatch.sh
2739 tools/testing/selftests/livepatch/test-shadow-vars.sh
2740
2741 If unsure, say N.
2742
0a020d41
JP
2743config TEST_OBJAGG
2744 tristate "Perform selftest on object aggreration manager"
2745 default n
2746 depends on OBJAGG
2747 help
2748 Enable this option to test object aggregation manager on boot
2749 (or module load).
2750
5015a300
AP
2751config TEST_MEMINIT
2752 tristate "Test heap/page initialization"
2753 help
2754 Test if the kernel is zero-initializing heap and page allocations.
2755 This can be useful to test init_on_alloc and init_on_free features.
2756
2757 If unsure, say N.
2758
b2ef9f5a
RC
2759config TEST_HMM
2760 tristate "Test HMM (Heterogeneous Memory Management)"
2761 depends on TRANSPARENT_HUGEPAGE
2762 depends on DEVICE_PRIVATE
2763 select HMM_MIRROR
2764 select MMU_NOTIFIER
2765 help
2766 This is a pseudo device driver solely for testing HMM.
2767 Say M here if you want to build the HMM test module.
2768 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2769
2770 If unsure, say N.
2771
e320d301
MWO
2772config TEST_FREE_PAGES
2773 tristate "Test freeing pages"
2774 help
2775 Test that a memory leak does not occur due to a race between
2776 freeing a block of pages and a speculative page reference.
2777 Loading this module is safe if your kernel has the bug fixed.
2778 If the bug is not fixed, it will leak gigabytes of memory and
2779 probably OOM your system.
2780
4185b3b9
PA
2781config TEST_FPU
2782 tristate "Test floating point operations in kernel space"
2783 depends on X86 && !KCOV_INSTRUMENT_ALL
2784 help
2785 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2786 which will trigger a sequence of floating point operations. This is used
2787 for self-testing floating point control register setting in
2788 kernel_fpu_begin().
2789
2790 If unsure, say N.
2791
1253b9b8
PM
2792config TEST_CLOCKSOURCE_WATCHDOG
2793 tristate "Test clocksource watchdog in kernel space"
2794 depends on CLOCKSOURCE_WATCHDOG
2795 help
2796 Enable this option to create a kernel module that will trigger
2797 a test of the clocksource watchdog. This module may be loaded
2798 via modprobe or insmod in which case it will run upon being
2799 loaded, or it may be built in, in which case it will run
2800 shortly after boot.
2801
2802 If unsure, say N.
2803
d3deafaa 2804endif # RUNTIME_TESTING_MENU
cc3fa840 2805
dce44566
AK
2806config ARCH_USE_MEMTEST
2807 bool
2808 help
2809 An architecture should select this when it uses early_memtest()
2810 during boot process.
2811
cc3fa840
RD
2812config MEMTEST
2813 bool "Memtest"
dce44566 2814 depends on ARCH_USE_MEMTEST
a7f7f624 2815 help
cc3fa840 2816 This option adds a kernel parameter 'memtest', which allows memtest
dce44566 2817 to be set and executed.
cc3fa840
RD
2818 memtest=0, mean disabled; -- default
2819 memtest=1, mean do 1 test pattern;
2820 ...
2821 memtest=17, mean do 17 test patterns.
2822 If you are unsure how to answer this question, answer N.
2823
21266be9 2824
06ec64b8 2825
af9ca6f9
BB
2826config HYPERV_TESTING
2827 bool "Microsoft Hyper-V driver testing"
2828 default n
2829 depends on HYPERV && DEBUG_FS
2830 help
2831 Select this option to enable Hyper-V vmbus testing.
2832
045f6d79
CD
2833endmenu # "Kernel Testing and Coverage"
2834
2f7ab126
MO
2835menu "Rust hacking"
2836
2837config RUST_DEBUG_ASSERTIONS
2838 bool "Debug assertions"
2839 depends on RUST
2840 help
2841 Enables rustc's `-Cdebug-assertions` codegen option.
2842
2843 This flag lets you turn `cfg(debug_assertions)` conditional
2844 compilation on or off. This can be used to enable extra debugging
2845 code in development but not in production. For example, it controls
2846 the behavior of the standard library's `debug_assert!` macro.
2847
2848 Note that this will apply to all Rust code, including `core`.
2849
2850 If unsure, say N.
2851
2852config RUST_OVERFLOW_CHECKS
2853 bool "Overflow checks"
2854 default y
2855 depends on RUST
2856 help
2857 Enables rustc's `-Coverflow-checks` codegen option.
2858
2859 This flag allows you to control the behavior of runtime integer
2860 overflow. When overflow-checks are enabled, a Rust panic will occur
2861 on overflow.
2862
2863 Note that this will apply to all Rust code, including `core`.
2864
2865 If unsure, say Y.
2866
ecaa6ddf
GG
2867config RUST_BUILD_ASSERT_ALLOW
2868 bool "Allow unoptimized build-time assertions"
2869 depends on RUST
2870 help
2871 Controls how are `build_error!` and `build_assert!` handled during build.
2872
2873 If calls to them exist in the binary, it may indicate a violated invariant
2874 or that the optimizer failed to verify the invariant during compilation.
2875
2876 This should not happen, thus by default the build is aborted. However,
2877 as an escape hatch, you can choose Y here to ignore them during build
2878 and let the check be carried at runtime (with `panic!` being called if
2879 the check fails).
2880
2881 If unsure, say N.
2882
2f7ab126
MO
2883endmenu # "Rust"
2884
06ec64b8 2885endmenu # Kernel hacking