xref: /linux/lib/Kconfig.debug (revision 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d)
1# SPDX-License-Identifier: GPL-2.0-only
2menu "Kernel hacking"
3
4menu "printk and dmesg options"
5
6config PRINTK_TIME
7	bool "Show timing information on printks"
8	depends on PRINTK
9	help
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
19	  parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
20
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
38config PRINTK_EXECUTION_CTX
39	bool
40	depends on PRINTK
41	help
42	  This option extends struct printk_info to include extra execution
43	  context in printk, such as task name and CPU number from where the
44	  message originated. This is useful for correlating printk messages
45	  with specific execution contexts.
46
47	  This is automatically enabled when a console driver that supports
48	  execution context is selected.
49
50config STACKTRACE_BUILD_ID
51	bool "Show build ID information in stacktraces"
52	depends on PRINTK
53	help
54	  Selecting this option adds build ID information for symbols in
55	  stacktraces printed with the printk format '%p[SR]b'.
56
57	  This option is intended for distros where debuginfo is not easily
58	  accessible but can be downloaded given the build ID of the vmlinux or
59	  kernel module where the function is located.
60
61config CONSOLE_LOGLEVEL_DEFAULT
62	int "Default console loglevel (1-15)"
63	range 1 15
64	default "7"
65	help
66	  Default loglevel to determine what will be printed on the console.
67
68	  Setting a default here is equivalent to passing in loglevel=<x> in
69	  the kernel bootargs. loglevel=<x> continues to override whatever
70	  value is specified here as well.
71
72	  Note: This does not affect the log level of un-prefixed printk()
73	  usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
74	  option.
75
76config CONSOLE_LOGLEVEL_QUIET
77	int "quiet console loglevel (1-15)"
78	range 1 15
79	default "4"
80	help
81	  loglevel to use when "quiet" is passed on the kernel commandline.
82
83	  When "quiet" is passed on the kernel commandline this loglevel
84	  will be used as the loglevel. IOW passing "quiet" will be the
85	  equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
86
87config MESSAGE_LOGLEVEL_DEFAULT
88	int "Default message log level (1-7)"
89	range 1 7
90	default "4"
91	help
92	  Default log level for printk statements with no specified priority.
93
94	  This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
95	  that are auditing their logs closely may want to set it to a lower
96	  priority.
97
98	  Note: This does not affect what message level gets printed on the console
99	  by default. To change that, use loglevel=<x> in the kernel bootargs,
100	  or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
101
102config BOOT_PRINTK_DELAY
103	bool "Delay each boot printk message by N milliseconds"
104	depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
105	help
106	  This build option allows you to read kernel boot messages
107	  by inserting a short delay after each one.  The delay is
108	  specified in milliseconds on the kernel command line,
109	  using "boot_delay=N".
110
111	  It is likely that you would also need to use "lpj=M" to preset
112	  the "loops per jiffy" value.
113	  See a previous boot log for the "lpj" value to use for your
114	  system, and then set "lpj=M" before setting "boot_delay=N".
115	  NOTE:  Using this option may adversely affect SMP systems.
116	  I.e., processors other than the first one may not boot up.
117	  BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
118	  what it believes to be lockup conditions.
119
120config DYNAMIC_DEBUG
121	bool "Enable dynamic printk() support"
122	default n
123	depends on PRINTK
124	depends on (DEBUG_FS || PROC_FS)
125	select DYNAMIC_DEBUG_CORE
126	help
127
128	  Compiles debug level messages into the kernel, which would not
129	  otherwise be available at runtime. These messages can then be
130	  enabled/disabled based on various levels of scope - per source file,
131	  function, module, format string, and line number. This mechanism
132	  implicitly compiles in all pr_debug() and dev_dbg() calls, which
133	  enlarges the kernel text size by about 2%.
134
135	  If a source file is compiled with DEBUG flag set, any
136	  pr_debug() calls in it are enabled by default, but can be
137	  disabled at runtime as below.  Note that DEBUG flag is
138	  turned on by many CONFIG_*DEBUG* options.
139
140	  Usage:
141
142	  Dynamic debugging is controlled via the 'dynamic_debug/control' file,
143	  which is contained in the 'debugfs' filesystem or procfs.
144	  Thus, the debugfs or procfs filesystem must first be mounted before
145	  making use of this feature.
146	  We refer the control file as: <debugfs>/dynamic_debug/control. This
147	  file contains a list of the debug statements that can be enabled. The
148	  format for each line of the file is:
149
150		filename:lineno [module]function flags format
151
152	  filename : source file of the debug statement
153	  lineno : line number of the debug statement
154	  module : module that contains the debug statement
155	  function : function that contains the debug statement
156	  flags : '=p' means the line is turned 'on' for printing
157	  format : the format used for the debug statement
158
159	  From a live system:
160
161		nullarbor:~ # cat <debugfs>/dynamic_debug/control
162		# filename:lineno [module]function flags format
163		fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
164		fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
165		fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
166
167	  Example usage:
168
169		// enable the message at line 1603 of file svcsock.c
170		nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
171						<debugfs>/dynamic_debug/control
172
173		// enable all the messages in file svcsock.c
174		nullarbor:~ # echo -n 'file svcsock.c +p' >
175						<debugfs>/dynamic_debug/control
176
177		// enable all the messages in the NFS server module
178		nullarbor:~ # echo -n 'module nfsd +p' >
179						<debugfs>/dynamic_debug/control
180
181		// enable all 12 messages in the function svc_process()
182		nullarbor:~ # echo -n 'func svc_process +p' >
183						<debugfs>/dynamic_debug/control
184
185		// disable all 12 messages in the function svc_process()
186		nullarbor:~ # echo -n 'func svc_process -p' >
187						<debugfs>/dynamic_debug/control
188
189	  See Documentation/admin-guide/dynamic-debug-howto.rst for additional
190	  information.
191
192config DYNAMIC_DEBUG_CORE
193	bool "Enable core function of dynamic debug support"
194	depends on PRINTK
195	depends on (DEBUG_FS || PROC_FS)
196	help
197	  Enable core functional support of dynamic debug. It is useful
198	  when you want to tie dynamic debug to your kernel modules with
199	  DYNAMIC_DEBUG_MODULE defined for each of them, especially for
200	  the case of embedded system where the kernel image size is
201	  sensitive for people.
202
203config SYMBOLIC_ERRNAME
204	bool "Support symbolic error names in printf"
205	default y if PRINTK
206	help
207	  If you say Y here, the kernel's printf implementation will
208	  be able to print symbolic error names such as ENOSPC instead
209	  of the number 28. It makes the kernel image slightly larger
210	  (about 3KB), but can make the kernel logs easier to read.
211
212config DEBUG_BUGVERBOSE
213	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
214	depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
215	default y
216	help
217	  Say Y here to make BUG() panics output the file name and line number
218	  of the BUG call as well as the EIP and oops trace.  This aids
219	  debugging but costs about 70-100K of memory.
220
221config DEBUG_BUGVERBOSE_DETAILED
222	bool "Verbose WARN_ON_ONCE() reporting (adds 100K)" if DEBUG_BUGVERBOSE
223	help
224	  Say Y here to make WARN_ON_ONCE() output the condition string of the
225	  warning, in addition to the file name and line number.
226	  This helps debugging, but costs about 100K of memory.
227
228	  Say N if unsure.
229
230
231endmenu # "printk and dmesg options"
232
233config DEBUG_KERNEL
234	bool "Kernel debugging"
235	help
236	  Say Y here if you are developing drivers or trying to debug and
237	  identify kernel problems.
238
239config DEBUG_MISC
240	bool "Miscellaneous debug code"
241	default DEBUG_KERNEL
242	depends on DEBUG_KERNEL
243	help
244	  Say Y here if you need to enable miscellaneous debug code that should
245	  be under a more specific debug option but isn't.
246
247menu "Compile-time checks and compiler options"
248
249config DEBUG_INFO
250	bool
251	help
252	  A kernel debug info option other than "None" has been selected
253	  in the "Debug information" choice below, indicating that debug
254	  information will be generated for build targets.
255
256# Clang generates .uleb128 with label differences for DWARF v5, a feature that
257# older binutils ports do not support when utilizing RISC-V style linker
258# relaxation: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
259config AS_HAS_NON_CONST_ULEB128
260	def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
261
262choice
263	prompt "Debug information"
264	depends on DEBUG_KERNEL
265	help
266	  Selecting something other than "None" results in a kernel image
267	  that will include debugging info resulting in a larger kernel image.
268	  This adds debug symbols to the kernel and modules (gcc -g), and
269	  is needed if you intend to use kernel crashdump or binary object
270	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
271
272	  Choose which version of DWARF debug info to emit. If unsure,
273	  select "Toolchain default".
274
275config DEBUG_INFO_NONE
276	bool "Disable debug information"
277	help
278	  Do not build the kernel with debugging information, which will
279	  result in a faster and smaller build.
280
281config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
282	bool "Rely on the toolchain's implicit default DWARF version"
283	select DEBUG_INFO
284	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
285	help
286	  The implicit default version of DWARF debug info produced by a
287	  toolchain changes over time.
288
289	  This can break consumers of the debug info that haven't upgraded to
290	  support newer revisions, and prevent testing newer versions, but
291	  those should be less common scenarios.
292
293config DEBUG_INFO_DWARF4
294	bool "Generate DWARF Version 4 debuginfo"
295	select DEBUG_INFO
296	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
297	help
298	  Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
299	  if using clang without clang's integrated assembler, and gdb 7.0+.
300
301	  If you have consumers of DWARF debug info that are not ready for
302	  newer revisions of DWARF, you may wish to choose this or have your
303	  config select this.
304
305config DEBUG_INFO_DWARF5
306	bool "Generate DWARF Version 5 debuginfo"
307	select DEBUG_INFO
308	depends on !ARCH_HAS_BROKEN_DWARF5
309	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
310	help
311	  Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
312	  5.0+ accepts the -gdwarf-5 flag but only had partial support for some
313	  draft features until 7.0), and gdb 8.0+.
314
315	  Changes to the structure of debug info in Version 5 allow for around
316	  15-18% savings in resulting image and debug info section sizes as
317	  compared to DWARF Version 4. DWARF Version 5 standardizes previous
318	  extensions such as accelerators for symbol indexing and the format
319	  for fission (.dwo/.dwp) files. Users may not want to select this
320	  config if they rely on tooling that has not yet been updated to
321	  support DWARF Version 5.
322
323endchoice # "Debug information"
324
325if DEBUG_INFO
326
327config DEBUG_INFO_REDUCED
328	bool "Reduce debugging information"
329	help
330	  If you say Y here gcc is instructed to generate less debugging
331	  information for structure types. This means that tools that
332	  need full debugging information (like kgdb or systemtap) won't
333	  be happy. But if you merely need debugging information to
334	  resolve line numbers there is no loss. Advantage is that
335	  build directory object sizes shrink dramatically over a full
336	  DEBUG_INFO build and compile times are reduced too.
337	  Only works with newer gcc versions.
338
339choice
340	prompt "Compressed Debug information"
341	help
342	  Compress the resulting debug info. Results in smaller debug info sections,
343	  but requires that consumers are able to decompress the results.
344
345	  If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
346
347config DEBUG_INFO_COMPRESSED_NONE
348	bool "Don't compress debug information"
349	help
350	  Don't compress debug info sections.
351
352config DEBUG_INFO_COMPRESSED_ZLIB
353	bool "Compress debugging information with zlib"
354	depends on $(cc-option,-gz=zlib)
355	depends on $(ld-option,--compress-debug-sections=zlib)
356	help
357	  Compress the debug information using zlib.
358
359	  Users of dpkg-deb via debian/rules may find an increase in
360	  size of their debug .deb packages with this config set, due to the
361	  debug info being compressed with zlib, then the object files being
362	  recompressed with a different compression scheme. But this is still
363	  preferable to setting KDEB_COMPRESS or DPKG_DEB_COMPRESSOR_TYPE to
364	  "none" which would be even larger.
365
366config DEBUG_INFO_COMPRESSED_ZSTD
367	bool "Compress debugging information with zstd"
368	depends on $(cc-option,-gz=zstd)
369	depends on $(ld-option,--compress-debug-sections=zstd)
370	help
371	  Compress the debug information using zstd.  This may provide better
372	  compression than zlib, for about the same time costs, but requires newer
373	  toolchain support.  Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
374	  zstd.
375
376endchoice # "Compressed Debug information"
377
378config DEBUG_INFO_SPLIT
379	bool "Produce split debuginfo in .dwo files"
380	depends on $(cc-option,-gsplit-dwarf)
381	# RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC
382	# prior to 12.x:
383	# https://github.com/llvm/llvm-project/issues/56642
384	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090
385	depends on !RISCV || GCC_VERSION >= 120000
386	help
387	  Generate debug info into separate .dwo files. This significantly
388	  reduces the build directory size for builds with DEBUG_INFO,
389	  because it stores the information only once on disk in .dwo
390	  files instead of multiple times in object files and executables.
391	  In addition the debug information is also compressed.
392
393	  Requires recent gcc (4.7+) and recent gdb/binutils.
394	  Any tool that packages or reads debug information would need
395	  to know about the .dwo files and include them.
396	  Incompatible with older versions of ccache.
397
398config DEBUG_INFO_BTF
399	bool "Generate BTF type information"
400	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
401	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
402	depends on BPF_SYSCALL
403	depends on PAHOLE_VERSION >= 122
404	# pahole uses elfutils, which does not have support for Hexagon relocations
405	depends on !HEXAGON
406	help
407	  Generate deduplicated BTF type information from DWARF debug info.
408	  Turning this on requires pahole v1.22 or later, which will convert
409	  DWARF type info into equivalent deduplicated BTF type info.
410
411config PAHOLE_HAS_BTF_TAG
412	def_bool PAHOLE_VERSION >= 123
413	depends on CC_IS_CLANG
414	help
415	  Decide whether pahole emits btf_tag attributes (btf_type_tag and
416	  btf_decl_tag) or not. Currently only clang compiler implements
417	  these attributes, so make the config depend on CC_IS_CLANG.
418
419config PAHOLE_HAS_LANG_EXCLUDE
420	def_bool PAHOLE_VERSION >= 124
421	help
422	  Support for the --lang_exclude flag which makes pahole exclude
423	  compilation units from the supplied language. Used in Kbuild to
424	  omit Rust CUs which are not supported in version 1.24 of pahole,
425	  otherwise it would emit malformed kernel and module binaries when
426	  using DEBUG_INFO_BTF_MODULES.
427
428config DEBUG_INFO_BTF_MODULES
429	bool "Generate BTF type information for kernel modules"
430	default y
431	depends on DEBUG_INFO_BTF && MODULES
432	help
433	  Generate compact split BTF type information for kernel modules.
434
435config MODULE_ALLOW_BTF_MISMATCH
436	bool "Allow loading modules with non-matching BTF type info"
437	depends on DEBUG_INFO_BTF_MODULES
438	help
439	  For modules whose split BTF does not match vmlinux, load without
440	  BTF rather than refusing to load. The default behavior with
441	  module BTF enabled is to reject modules with such mismatches;
442	  this option will still load module BTF where possible but ignore
443	  it when a mismatch is found.
444
445config GDB_SCRIPTS
446	bool "Provide GDB scripts for kernel debugging"
447	help
448	  This creates the required links to GDB helper scripts in the
449	  build directory. If you load vmlinux into gdb, the helper
450	  scripts will be automatically imported by gdb as well, and
451	  additional functions are available to analyze a Linux kernel
452	  instance. See Documentation/process/debugging/gdb-kernel-debugging.rst
453	  for further details.
454
455endif # DEBUG_INFO
456
457config FRAME_WARN
458	int "Warn for stack frames larger than"
459	range 0 8192
460	default 0 if KMSAN
461	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
462	default 2048 if PARISC
463	default 1536 if (!64BIT && XTENSA)
464	default 1280 if !64BIT
465	default 2048 if 64BIT
466	help
467	  Tell the compiler to warn at build time for stack frames larger than this.
468	  Setting this too low will cause a lot of warnings.
469	  Setting it to 0 disables the warning.
470
471config STRIP_ASM_SYMS
472	bool "Strip assembler-generated symbols during link"
473	default n
474	help
475	  Strip internal assembler-generated symbols during a link (symbols
476	  that look like '.Lxxx') so they don't pollute the output of
477	  get_wchan() and suchlike.
478
479config READABLE_ASM
480	bool "Generate readable assembler code"
481	depends on DEBUG_KERNEL
482	depends on CC_IS_GCC
483	help
484	  Disable some compiler optimizations that tend to generate human unreadable
485	  assembler output. This may make the kernel slightly slower, but it helps
486	  to keep kernel developers who have to stare a lot at assembler listings
487	  sane.
488
489config HEADERS_INSTALL
490	bool "Install uapi headers to usr/include"
491	help
492	  This option will install uapi headers (headers exported to user-space)
493	  into the usr/include directory for use during the kernel build.
494	  This is unneeded for building the kernel itself, but needed for some
495	  user-space program samples. It is also needed by some features such
496	  as uapi header sanity checks.
497
498config DEBUG_SECTION_MISMATCH
499	bool "Enable full Section mismatch analysis"
500	depends on CC_IS_GCC
501	help
502	  The section mismatch analysis checks if there are illegal references
503	  from one section to another. During linktime or runtime, some
504	  sections are dropped; any use of code/data previously in these
505	  sections would most likely result in an oops.
506
507	  In the code, functions and variables are annotated with __init,
508	  __initdata, and so on (see the full list in include/linux/init.h).
509	  This directs the toolchain to place code/data in specific sections.
510
511	  The section mismatch analysis is always performed after a full
512	  kernel build, and enabling this option causes the option
513	  -fno-inline-functions-called-once to be added to gcc commands.
514
515	  However, when inlining a function annotated with __init in
516	  a non-init function, we would lose the section information and thus
517	  the analysis would not catch the illegal reference.  This option
518	  tells gcc to inline less (but it does result in a larger kernel).
519
520config SECTION_MISMATCH_WARN_ONLY
521	bool "Make section mismatch errors non-fatal"
522	default y
523	help
524	  If you say N here, the build process will fail if there are any
525	  section mismatch, instead of just throwing warnings.
526
527	  If unsure, say Y.
528
529config DEBUG_FORCE_FUNCTION_ALIGN_64B
530	bool "Force all function address 64B aligned"
531	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390)
532	select FUNCTION_ALIGNMENT_64B
533	help
534	  There are cases that a commit from one domain changes the function
535	  address alignment of other domains, and cause magic performance
536	  bump (regression or improvement). Enable this option will help to
537	  verify if the bump is caused by function alignment changes, while
538	  it will slightly increase the kernel size and affect icache usage.
539
540	  It is mainly for debug and performance tuning use.
541
542#
543# Select this config option from the architecture Kconfig, if it
544# is preferred to always offer frame pointers as a config
545# option on the architecture (regardless of KERNEL_DEBUG):
546#
547config ARCH_WANT_FRAME_POINTERS
548	bool
549
550config FRAME_POINTER
551	bool "Compile the kernel with frame pointers"
552	depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
553	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
554	help
555	  If you say Y here the resulting kernel image will be slightly
556	  larger and slower, but it gives very useful debugging information
557	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
558
559config OBJTOOL
560	bool
561
562config OBJTOOL_WERROR
563	bool "Upgrade objtool warnings to errors"
564	depends on OBJTOOL && !COMPILE_TEST
565	help
566	  Fail the build on objtool warnings.
567
568	  Objtool warnings can indicate kernel instability, including boot
569	  failures.  This option is highly recommended.
570
571	  If unsure, say Y.
572
573config STACK_VALIDATION
574	bool "Compile-time stack metadata validation"
575	depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
576	select OBJTOOL
577	default n
578	help
579	  Validate frame pointer rules at compile-time.  This helps ensure that
580	  runtime stack traces are more reliable.
581
582	  For more information, see
583	  tools/objtool/Documentation/objtool.txt.
584
585config NOINSTR_VALIDATION
586	bool
587	depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
588	select OBJTOOL
589	default y
590
591config VMLINUX_MAP
592	bool "Generate vmlinux.map file when linking"
593	depends on EXPERT
594	help
595	  Selecting this option will pass "-Map=vmlinux.map" to ld
596	  when linking vmlinux. That file can be useful for verifying
597	  and debugging magic section games, and for seeing which
598	  pieces of code get eliminated with
599	  CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
600
601config BUILTIN_MODULE_RANGES
602	bool "Generate address range information for builtin modules"
603	depends on !LTO
604	depends on VMLINUX_MAP
605	help
606	 When modules are built into the kernel, there will be no module name
607	 associated with its symbols in /proc/kallsyms.  Tracers may want to
608	 identify symbols by module name and symbol name regardless of whether
609	 the module is configured as loadable or not.
610
611	 This option generates modules.builtin.ranges in the build tree with
612	 offset ranges (per ELF section) for the module(s) they belong to.
613	 It also records an anchor symbol to determine the load address of the
614	 section.
615
616config WARN_CONTEXT_ANALYSIS
617	bool "Compiler context-analysis warnings"
618	depends on CC_IS_CLANG && CLANG_VERSION >= 230000
619	# Branch profiling re-defines "if", which messes with the compiler's
620	# ability to analyze __cond_acquires(..), resulting in false positives.
621	depends on !TRACE_BRANCH_PROFILING
622	default y
623	help
624	  Context Analysis is a language extension, which enables statically
625	  checking that required contexts are active (or inactive) by acquiring
626	  and releasing user-definable "context locks".
627
628	  Clang's name of the feature is "Thread Safety Analysis". Requires
629	  Clang 23 or later.
630
631	  Produces warnings by default. Select CONFIG_WERROR if you wish to
632	  turn these warnings into errors.
633
634	  For more details, see Documentation/dev-tools/context-analysis.rst.
635
636config WARN_CONTEXT_ANALYSIS_ALL
637	bool "Enable context analysis for all source files"
638	depends on WARN_CONTEXT_ANALYSIS
639	depends on EXPERT && !COMPILE_TEST
640	help
641	  Enable tree-wide context analysis. This is likely to produce a
642	  large number of false positives - enable at your own risk.
643
644	  If unsure, say N.
645
646endmenu # "Compiler options"
647
648menu "Generic Kernel Debugging Instruments"
649
650config MAGIC_SYSRQ
651	bool "Magic SysRq key"
652	depends on !UML
653	help
654	  If you say Y here, you will have some control over the system even
655	  if the system crashes for example during kernel debugging (e.g., you
656	  will be able to flush the buffer cache to disk, reboot the system
657	  immediately or dump some status information). This is accomplished
658	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
659	  also works on a serial console (on PC hardware at least), if you
660	  send a BREAK and then within 5 seconds a command keypress. The
661	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
662	  Don't say Y unless you really know what this hack does.
663
664config MAGIC_SYSRQ_DEFAULT_ENABLE
665	hex "Enable magic SysRq key functions by default"
666	depends on MAGIC_SYSRQ
667	default 0x1
668	help
669	  Specifies which SysRq key functions are enabled by default.
670	  This may be set to 1 or 0 to enable or disable them all, or
671	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
672
673config MAGIC_SYSRQ_SERIAL
674	bool "Enable magic SysRq key over serial"
675	depends on MAGIC_SYSRQ
676	default y
677	help
678	  Many embedded boards have a disconnected TTL level serial which can
679	  generate some garbage that can lead to spurious false sysrq detects.
680	  This option allows you to decide whether you want to enable the
681	  magic SysRq key.
682
683config MAGIC_SYSRQ_SERIAL_SEQUENCE
684	string "Char sequence that enables magic SysRq over serial"
685	depends on MAGIC_SYSRQ_SERIAL
686	default ""
687	help
688	  Specifies a sequence of characters that can follow BREAK to enable
689	  SysRq on a serial console.
690
691	  If unsure, leave an empty string and the option will not be enabled.
692
693config DEBUG_FS
694	bool "Debug Filesystem"
695	help
696	  debugfs is a virtual file system that kernel developers use to put
697	  debugging files into.  Enable this option to be able to read and
698	  write to these files.
699
700	  For detailed documentation on the debugfs API, see
701	  Documentation/filesystems/.
702
703	  If unsure, say N.
704
705choice
706	prompt "Debugfs default access"
707	depends on DEBUG_FS
708	default DEBUG_FS_ALLOW_ALL
709	help
710	  This selects the default access restrictions for debugfs.
711	  It can be overridden with kernel command line option
712	  debugfs=[on,off]. The restrictions apply for API access
713	  and filesystem registration.
714
715config DEBUG_FS_ALLOW_ALL
716	bool "Access normal"
717	help
718	  No restrictions apply. Both API and filesystem registration
719	  is on. This is the normal default operation.
720
721config DEBUG_FS_ALLOW_NONE
722	bool "No access"
723	help
724	  Access is off. Clients get -PERM when trying to create nodes in
725	  debugfs tree and debugfs is not registered as a filesystem.
726	  Client can then back-off or continue without debugfs access.
727
728endchoice
729
730source "lib/Kconfig.kgdb"
731source "lib/Kconfig.ubsan"
732source "lib/Kconfig.kcsan"
733
734endmenu
735
736menu "Networking Debugging"
737
738source "net/Kconfig.debug"
739
740endmenu # "Networking Debugging"
741
742menu "Memory Debugging"
743
744source "mm/Kconfig.debug"
745
746config DEBUG_OBJECTS
747	bool "Debug object operations"
748	depends on PREEMPT_COUNT || !DEFERRED_STRUCT_PAGE_INIT
749	depends on DEBUG_KERNEL
750	help
751	  If you say Y here, additional code will be inserted into the
752	  kernel to track the life time of various objects and validate
753	  the operations on those objects.
754
755config DEBUG_OBJECTS_SELFTEST
756	bool "Debug objects selftest"
757	depends on DEBUG_OBJECTS
758	help
759	  This enables the selftest of the object debug code.
760
761config DEBUG_OBJECTS_FREE
762	bool "Debug objects in freed memory"
763	depends on DEBUG_OBJECTS
764	help
765	  This enables checks whether a k/v free operation frees an area
766	  which contains an object which has not been deactivated
767	  properly. This can make kmalloc/kfree-intensive workloads
768	  much slower.
769
770config DEBUG_OBJECTS_TIMERS
771	bool "Debug timer objects"
772	depends on DEBUG_OBJECTS
773	help
774	  If you say Y here, additional code will be inserted into the
775	  timer routines to track the life time of timer objects and
776	  validate the timer operations.
777
778config DEBUG_OBJECTS_WORK
779	bool "Debug work objects"
780	depends on DEBUG_OBJECTS
781	help
782	  If you say Y here, additional code will be inserted into the
783	  work queue routines to track the life time of work objects and
784	  validate the work operations.
785
786config DEBUG_OBJECTS_RCU_HEAD
787	bool "Debug RCU callbacks objects"
788	depends on DEBUG_OBJECTS
789	help
790	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
791
792config DEBUG_OBJECTS_PERCPU_COUNTER
793	bool "Debug percpu counter objects"
794	depends on DEBUG_OBJECTS
795	help
796	  If you say Y here, additional code will be inserted into the
797	  percpu counter routines to track the life time of percpu counter
798	  objects and validate the percpu counter operations.
799
800config DEBUG_OBJECTS_ENABLE_DEFAULT
801	int "debug_objects bootup default value (0-1)"
802	range 0 1
803	default "1"
804	depends on DEBUG_OBJECTS
805	help
806	  Debug objects boot parameter default value
807
808config SHRINKER_DEBUG
809	bool "Enable shrinker debugging support"
810	depends on DEBUG_FS
811	help
812	  Say Y to enable the shrinker debugfs interface which provides
813	  visibility into the kernel memory shrinkers subsystem.
814	  Disable it to avoid an extra memory footprint.
815
816config DEBUG_STACK_USAGE
817	bool "Stack utilization instrumentation"
818	depends on DEBUG_KERNEL
819	help
820	  Enables the display of the minimum amount of free stack which each
821	  task has ever had available in the sysrq-T and sysrq-P debug output.
822	  Also emits a message to dmesg when a process exits if that process
823	  used more stack space than previously exiting processes.
824
825	  This option will slow down process creation somewhat.
826
827config SCHED_STACK_END_CHECK
828	bool "Detect stack corruption on calls to schedule()"
829	depends on DEBUG_KERNEL
830	default n
831	help
832	  This option checks for a stack overrun on calls to schedule().
833	  If the stack end location is found to be over written always panic as
834	  the content of the corrupted region can no longer be trusted.
835	  This is to ensure no erroneous behaviour occurs which could result in
836	  data corruption or a sporadic crash at a later stage once the region
837	  is examined. The runtime overhead introduced is minimal.
838
839config ARCH_HAS_DEBUG_VM_PGTABLE
840	bool
841	help
842	  An architecture should select this when it can successfully
843	  build and run DEBUG_VM_PGTABLE.
844
845config DEBUG_VFS
846	bool "Debug VFS"
847	depends on DEBUG_KERNEL
848	help
849	  Enable this to turn on extended checks in the VFS layer that may impact
850	  performance.
851
852	  If unsure, say N.
853
854config DEBUG_VM_IRQSOFF
855	def_bool DEBUG_VM && !PREEMPT_RT
856
857config DEBUG_VM
858	bool "Debug VM"
859	depends on DEBUG_KERNEL
860	help
861	  Enable this to turn on extended checks in the virtual-memory system
862	  that may impact performance.
863
864	  If unsure, say N.
865
866config DEBUG_VM_SHOOT_LAZIES
867	bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
868	depends on DEBUG_VM
869	depends on MMU_LAZY_TLB_SHOOTDOWN
870	help
871	  Enable additional IPIs that ensure lazy tlb mm references are removed
872	  before the mm is freed.
873
874	  If unsure, say N.
875
876config DEBUG_VM_MAPLE_TREE
877	bool "Debug VM maple trees"
878	depends on DEBUG_VM
879	select DEBUG_MAPLE_TREE
880	help
881	  Enable VM maple tree debugging information and extra validations.
882
883	  If unsure, say N.
884
885config DEBUG_VM_RB
886	bool "Debug VM red-black trees"
887	depends on DEBUG_VM
888	help
889	  Enable VM red-black tree debugging information and extra validations.
890
891	  If unsure, say N.
892
893config DEBUG_VM_PGFLAGS
894	bool "Debug page-flags operations"
895	depends on DEBUG_VM
896	help
897	  Enables extra validation on page flags operations.
898
899	  If unsure, say N.
900
901config DEBUG_VM_PGTABLE
902	bool "Debug arch page table for semantics compliance"
903	depends on MMU
904	depends on ARCH_HAS_DEBUG_VM_PGTABLE
905	default y if DEBUG_VM
906	help
907	  This option provides a debug method which can be used to test
908	  architecture page table helper functions on various platforms in
909	  verifying if they comply with expected generic MM semantics. This
910	  will help architecture code in making sure that any changes or
911	  new additions of these helpers still conform to expected
912	  semantics of the generic MM. Platforms will have to opt in for
913	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
914
915	  If unsure, say N.
916
917config ARCH_HAS_DEBUG_VIRTUAL
918	bool
919
920config DEBUG_VIRTUAL
921	bool "Debug VM translations"
922	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
923	help
924	  Enable some costly sanity checks in virtual to page code. This can
925	  catch mistakes with virt_to_page() and friends.
926
927	  If unsure, say N.
928
929config DEBUG_NOMMU_REGIONS
930	bool "Debug the global anon/private NOMMU mapping region tree"
931	depends on DEBUG_KERNEL && !MMU
932	help
933	  This option causes the global tree of anonymous and private mapping
934	  regions to be regularly checked for invalid topology.
935
936config DEBUG_MEMORY_INIT
937	bool "Debug memory initialisation" if EXPERT
938	default !EXPERT
939	help
940	  Enable this for additional checks during memory initialisation.
941	  The sanity checks verify aspects of the VM such as the memory model
942	  and other information provided by the architecture. Verbose
943	  information will be printed at KERN_DEBUG loglevel depending
944	  on the mminit_loglevel= command-line option.
945
946	  If unsure, say Y
947
948config MEMORY_NOTIFIER_ERROR_INJECT
949	tristate "Memory hotplug notifier error injection module"
950	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
951	help
952	  This option provides the ability to inject artificial errors to
953	  memory hotplug notifier chain callbacks.  It is controlled through
954	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
955
956	  If the notifier call chain should be failed with some events
957	  notified, write the error code to "actions/<notifier event>/error".
958
959	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
960
961	  # cd /sys/kernel/debug/notifier-error-inject/memory
962	  # echo -12 > actions/MEM_GOING_OFFLINE/error
963	  # echo offline > /sys/devices/system/memory/memoryXXX/state
964	  bash: echo: write error: Cannot allocate memory
965
966	  To compile this code as a module, choose M here: the module will
967	  be called memory-notifier-error-inject.
968
969	  If unsure, say N.
970
971config DEBUG_PER_CPU_MAPS
972	bool "Debug access to per_cpu maps"
973	depends on DEBUG_KERNEL
974	depends on SMP
975	help
976	  Say Y to verify that the per_cpu map being accessed has
977	  been set up. This adds a fair amount of code to kernel memory
978	  and decreases performance.
979
980	  Say N if unsure.
981
982config DEBUG_KMAP_LOCAL
983	bool "Debug kmap_local temporary mappings"
984	depends on DEBUG_KERNEL && KMAP_LOCAL
985	help
986	  This option enables additional error checking for the kmap_local
987	  infrastructure.  Disable for production use.
988
989config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
990	bool
991
992config DEBUG_KMAP_LOCAL_FORCE_MAP
993	bool "Enforce kmap_local temporary mappings"
994	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
995	select KMAP_LOCAL
996	select DEBUG_KMAP_LOCAL
997	help
998	  This option enforces temporary mappings through the kmap_local
999	  mechanism for non-highmem pages and on non-highmem systems.
1000	  Disable this for production systems!
1001
1002config DEBUG_HIGHMEM
1003	bool "Highmem debugging"
1004	depends on DEBUG_KERNEL && HIGHMEM
1005	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
1006	select DEBUG_KMAP_LOCAL
1007	help
1008	  This option enables additional error checking for high memory
1009	  systems.  Disable for production systems.
1010
1011config HAVE_DEBUG_STACKOVERFLOW
1012	bool
1013
1014config DEBUG_STACKOVERFLOW
1015	bool "Check for stack overflows"
1016	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
1017	help
1018	  Say Y here if you want to check for overflows of kernel, IRQ
1019	  and exception stacks (if your architecture uses them). This
1020	  option will show detailed messages if free stack space drops
1021	  below a certain limit.
1022
1023	  These kinds of bugs usually occur when call-chains in the
1024	  kernel get too deep, especially when interrupts are
1025	  involved.
1026
1027	  Use this in cases where you see apparently random memory
1028	  corruption, especially if it appears in 'struct thread_info'
1029
1030	  If in doubt, say "N".
1031
1032config CODE_TAGGING
1033	bool
1034	select KALLSYMS
1035
1036source "lib/Kconfig.kasan"
1037source "lib/Kconfig.kfence"
1038source "lib/Kconfig.kmsan"
1039
1040endmenu # "Memory Debugging"
1041
1042config DEBUG_SHIRQ
1043	bool "Debug shared IRQ handlers"
1044	depends on DEBUG_KERNEL
1045	help
1046	  Enable this to generate a spurious interrupt just before a shared
1047	  interrupt handler is deregistered (generating one when registering
1048	  is currently disabled). Drivers need to handle this correctly. Some
1049	  don't and need to be caught.
1050
1051menu "Debug Oops, Lockups and Hangs"
1052
1053config PANIC_ON_OOPS
1054	bool "Panic on Oops"
1055	help
1056	  Say Y here to enable the kernel to panic when it oopses. This
1057	  has the same effect as setting oops=panic on the kernel command
1058	  line.
1059
1060	  This feature is useful to ensure that the kernel does not do
1061	  anything erroneous after an oops which could result in data
1062	  corruption or other issues.
1063
1064	  Say N if unsure.
1065
1066config PANIC_TIMEOUT
1067	int "panic timeout"
1068	default 0
1069	help
1070	  Set the timeout value (in seconds) until a reboot occurs when
1071	  the kernel panics. If n = 0, then we wait forever. A timeout
1072	  value n > 0 will wait n seconds before rebooting, while a timeout
1073	  value n < 0 will reboot immediately. This setting can be overridden
1074	  with the kernel command line option panic=, and from userspace via
1075	  /proc/sys/kernel/panic.
1076
1077config LOCKUP_DETECTOR
1078	bool
1079
1080config SOFTLOCKUP_DETECTOR
1081	bool "Detect Soft Lockups"
1082	depends on DEBUG_KERNEL && !S390
1083	select LOCKUP_DETECTOR
1084	help
1085	  Say Y here to enable the kernel to act as a watchdog to detect
1086	  soft lockups.
1087
1088	  Softlockups are bugs that cause the kernel to loop in kernel
1089	  mode for more than 20 seconds, without giving other tasks a
1090	  chance to run.  The current stack trace is displayed upon
1091	  detection and the system will stay locked up.
1092
1093config SOFTLOCKUP_DETECTOR_INTR_STORM
1094	bool "Detect Interrupt Storm in Soft Lockups"
1095	depends on SOFTLOCKUP_DETECTOR && IRQ_TIME_ACCOUNTING
1096	select GENERIC_IRQ_STAT_SNAPSHOT
1097	default y if NR_CPUS <= 128
1098	help
1099	  Say Y here to enable the kernel to detect interrupt storm
1100	  during "soft lockups".
1101
1102	  "soft lockups" can be caused by a variety of reasons. If one is
1103	  caused by an interrupt storm, then the storming interrupts will not
1104	  be on the callstack. To detect this case, it is necessary to report
1105	  the CPU stats and the interrupt counts during the "soft lockups".
1106
1107config BOOTPARAM_SOFTLOCKUP_PANIC
1108	int "Panic (Reboot) On Soft Lockups"
1109	depends on SOFTLOCKUP_DETECTOR
1110	default 0
1111	help
1112	  Set to a non-zero value N to enable the kernel to panic on "soft
1113	  lockups", which are bugs that cause the kernel to loop in kernel
1114	  mode for more than (N * 20 seconds) (configurable using the
1115	  watchdog_thresh sysctl), without giving other tasks a chance to run.
1116
1117	  The panic can be used in combination with panic_timeout,
1118	  to cause the system to reboot automatically after a
1119	  lockup has been detected. This feature is useful for
1120	  high-availability systems that have uptime guarantees and
1121	  where a lockup must be resolved ASAP.
1122
1123	  Say 0 if unsure.
1124
1125config HAVE_HARDLOCKUP_DETECTOR_BUDDY
1126	bool
1127	depends on SMP
1128	default y
1129
1130#
1131# Global switch whether to build a hardlockup detector at all. It is available
1132# only when the architecture supports at least one implementation. There are
1133# two exceptions. The hardlockup detector is never enabled on:
1134#
1135#	s390: it reported many false positives there
1136#
1137#	sparc64: has a custom implementation which is not using the common
1138#		hardlockup command line options and sysctl interface.
1139#
1140config HARDLOCKUP_DETECTOR
1141	bool "Detect Hard Lockups"
1142	depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
1143	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
1144	imply HARDLOCKUP_DETECTOR_PERF
1145	imply HARDLOCKUP_DETECTOR_BUDDY
1146	imply HARDLOCKUP_DETECTOR_ARCH
1147	select LOCKUP_DETECTOR
1148
1149	help
1150	  Say Y here to enable the kernel to act as a watchdog to detect
1151	  hard lockups.
1152
1153	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1154	  for more than 10 seconds, without letting other interrupts have a
1155	  chance to run.  The current stack trace is displayed upon detection
1156	  and the system will stay locked up.
1157
1158#
1159# Note that arch-specific variants are always preferred.
1160#
1161config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1162	bool "Prefer the buddy CPU hardlockup detector"
1163	depends on HARDLOCKUP_DETECTOR
1164	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
1165	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1166	help
1167	  Say Y here to prefer the buddy hardlockup detector over the perf one.
1168
1169	  With the buddy detector, each CPU uses its softlockup hrtimer
1170	  to check that the next CPU is processing hrtimer interrupts by
1171	  verifying that a counter is increasing.
1172
1173	  This hardlockup detector is useful on systems that don't have
1174	  an arch-specific hardlockup detector or if resources needed
1175	  for the hardlockup detector are better used for other things.
1176
1177config HARDLOCKUP_DETECTOR_PERF
1178	bool
1179	depends on HARDLOCKUP_DETECTOR
1180	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
1181	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1182	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1183
1184config HARDLOCKUP_DETECTOR_BUDDY
1185	bool
1186	depends on HARDLOCKUP_DETECTOR
1187	depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1188	depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
1189	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1190	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1191
1192config HARDLOCKUP_DETECTOR_ARCH
1193	bool
1194	depends on HARDLOCKUP_DETECTOR
1195	depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1196	help
1197	  The arch-specific implementation of the hardlockup detector will
1198	  be used.
1199
1200#
1201# Both the "perf" and "buddy" hardlockup detectors count hrtimer
1202# interrupts. This config enables functions managing this common code.
1203#
1204config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1205	bool
1206	select SOFTLOCKUP_DETECTOR
1207
1208#
1209# Enables a timestamp based low pass filter to compensate for perf based
1210# hard lockup detection which runs too fast due to turbo modes.
1211#
1212config HARDLOCKUP_CHECK_TIMESTAMP
1213	bool
1214
1215config BOOTPARAM_HARDLOCKUP_PANIC
1216	bool "Panic (Reboot) On Hard Lockups"
1217	depends on HARDLOCKUP_DETECTOR
1218	help
1219	  Say Y here to enable the kernel to panic on "hard lockups",
1220	  which are bugs that cause the kernel to loop in kernel
1221	  mode with interrupts disabled for more than 10 seconds (configurable
1222	  using the watchdog_thresh sysctl).
1223
1224	  Say N if unsure.
1225
1226config DETECT_HUNG_TASK
1227	bool "Detect Hung Tasks"
1228	depends on DEBUG_KERNEL
1229	default SOFTLOCKUP_DETECTOR
1230	help
1231	  Say Y here to enable the kernel to detect "hung tasks",
1232	  which are bugs that cause the task to be stuck in
1233	  uninterruptible "D" state indefinitely.
1234
1235	  When a hung task is detected, the kernel will print the
1236	  current stack trace (which you should report), but the
1237	  task will stay in uninterruptible state. If lockdep is
1238	  enabled then all held locks will also be reported. This
1239	  feature has negligible overhead.
1240
1241config DEFAULT_HUNG_TASK_TIMEOUT
1242	int "Default timeout for hung task detection (in seconds)"
1243	depends on DETECT_HUNG_TASK
1244	default 120
1245	help
1246	  This option controls the default timeout (in seconds) used
1247	  to determine when a task has become non-responsive and should
1248	  be considered hung.
1249
1250	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1251	  sysctl or by writing a value to
1252	  /proc/sys/kernel/hung_task_timeout_secs.
1253
1254	  A timeout of 0 disables the check.  The default is two minutes.
1255	  Keeping the default should be fine in most cases.
1256
1257config BOOTPARAM_HUNG_TASK_PANIC
1258	int "Number of hung tasks to trigger kernel panic"
1259	depends on DETECT_HUNG_TASK
1260	default 0
1261	help
1262	  When set to a non-zero value, a kernel panic will be triggered
1263	  if the number of hung tasks found during a single scan reaches
1264	  this value.
1265
1266	  The panic can be used in combination with panic_timeout,
1267	  to cause the system to reboot automatically after a
1268	  hung task has been detected. This feature is useful for
1269	  high-availability systems that have uptime guarantees and
1270	  where a hung tasks must be resolved ASAP.
1271
1272	  Say 0 if unsure.
1273
1274config DETECT_HUNG_TASK_BLOCKER
1275	bool "Dump Hung Tasks Blocker"
1276	depends on DETECT_HUNG_TASK
1277	depends on !PREEMPT_RT
1278	default y
1279	help
1280	  Say Y here to show a possible blocker task's stacktrace when
1281	  a hung task is waiting on a mutex, semaphore, or rwsem.
1282	  This will add a bit of overhead but shows suspicious tasks and
1283	  call traces for waits on one of these locks.
1284
1285config WQ_WATCHDOG
1286	bool "Detect Workqueue Stalls"
1287	depends on DEBUG_KERNEL
1288	help
1289	  Say Y here to enable stall detection on workqueues.  If a
1290	  worker pool doesn't make forward progress on a pending work
1291	  item for over a given amount of time, 30s by default, a
1292	  warning message is printed along with dump of workqueue
1293	  state.  This can be configured through kernel parameter
1294	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1295
1296config BOOTPARAM_WQ_STALL_PANIC
1297	int "Panic on Nth workqueue stall"
1298	default 0
1299	range 0 100
1300	depends on WQ_WATCHDOG
1301	help
1302	  Set the number of workqueue stalls to trigger a kernel panic.
1303	  A workqueue stall occurs when a worker pool doesn't make forward
1304	  progress on a pending work item for over 30 seconds (configurable
1305	  using the workqueue.watchdog_thresh parameter).
1306
1307	  If n = 0, the kernel will not panic on stall. If n > 0, the kernel
1308	  will panic after n stall warnings.
1309
1310	  The panic can be used in combination with panic_timeout,
1311	  to cause the system to reboot automatically after a
1312	  stall has been detected. This feature is useful for
1313	  high-availability systems that have uptime guarantees and
1314	  where a stall must be resolved ASAP.
1315
1316	  This setting can be overridden at runtime via the
1317	  workqueue.panic_on_stall kernel parameter.
1318
1319config WQ_CPU_INTENSIVE_REPORT
1320	bool "Report per-cpu work items which hog CPU for too long"
1321	depends on DEBUG_KERNEL
1322	help
1323	  Say Y here to enable reporting of concurrency-managed per-cpu work
1324	  items that hog CPUs for longer than
1325	  workqueue.cpu_intensive_thresh_us. Workqueue automatically
1326	  detects and excludes them from concurrency management to prevent
1327	  them from stalling other per-cpu work items. Occassional
1328	  triggering may not necessarily indicate a problem. Repeated
1329	  triggering likely indicates that the work item should be switched
1330	  to use an unbound workqueue.
1331
1332config TEST_LOCKUP
1333	tristate "Test module to generate lockups"
1334	depends on m
1335	help
1336	  This builds the "test_lockup" module that helps to make sure
1337	  that watchdogs and lockup detectors are working properly.
1338
1339	  Depending on module parameters it could emulate soft or hard
1340	  lockup, "hung task", or locking arbitrary lock for a long time.
1341	  Also it could generate series of lockups with cooling-down periods.
1342
1343	  If unsure, say N.
1344
1345endmenu # "Debug lockups and hangs"
1346
1347menu "Scheduler Debugging"
1348
1349config SCHED_INFO
1350	bool
1351	default n
1352
1353config SCHEDSTATS
1354	bool "Collect scheduler statistics"
1355	depends on PROC_FS
1356	select SCHED_INFO
1357	help
1358	  If you say Y here, additional code will be inserted into the
1359	  scheduler and related routines to collect statistics about
1360	  scheduler behavior and provide them in /proc/schedstat.  These
1361	  stats may be useful for both tuning and debugging the scheduler
1362	  If you aren't debugging the scheduler or trying to tune a specific
1363	  application, you can say N to avoid the very slight overhead
1364	  this adds.
1365
1366endmenu
1367
1368config DEBUG_PREEMPT
1369	bool "Debug preemptible kernel"
1370	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1371	help
1372	  If you say Y here then the kernel will use a debug variant of the
1373	  commonly used smp_processor_id() function and will print warnings
1374	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1375	  will detect preemption count underflows.
1376
1377	  This option has potential to introduce high runtime overhead,
1378	  depending on workload as it triggers debugging routines for each
1379	  this_cpu operation. It should only be used for debugging purposes.
1380
1381config DEBUG_ATOMIC
1382	bool "Debug atomic variables"
1383	depends on DEBUG_KERNEL
1384	help
1385	  If you say Y here then the kernel will add a runtime alignment check
1386	  to atomic accesses. Useful for architectures that do not have trap on
1387	  mis-aligned access.
1388
1389	  This option has potentially significant overhead.
1390
1391config DEBUG_ATOMIC_LARGEST_ALIGN
1392	bool "Check alignment only up to __aligned_largest"
1393	depends on DEBUG_ATOMIC
1394	help
1395	  If you say Y here then the check for natural alignment of
1396	  atomic accesses will be constrained to the compiler's largest
1397	  alignment for scalar types.
1398
1399menu "Lock Debugging (spinlocks, mutexes, etc...)"
1400
1401config LOCK_DEBUGGING_SUPPORT
1402	bool
1403	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1404	default y
1405
1406config PROVE_LOCKING
1407	bool "Lock debugging: prove locking correctness"
1408	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1409	select LOCKDEP
1410	select DEBUG_SPINLOCK
1411	select DEBUG_MUTEXES if !PREEMPT_RT
1412	select DEBUG_RT_MUTEXES if RT_MUTEXES
1413	select DEBUG_RWSEMS if !PREEMPT_RT
1414	select DEBUG_WW_MUTEX_SLOWPATH
1415	select DEBUG_LOCK_ALLOC
1416	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1417	select TRACE_IRQFLAGS
1418	default n
1419	help
1420	 This feature enables the kernel to prove that all locking
1421	 that occurs in the kernel runtime is mathematically
1422	 correct: that under no circumstance could an arbitrary (and
1423	 not yet triggered) combination of observed locking
1424	 sequences (on an arbitrary number of CPUs, running an
1425	 arbitrary number of tasks and interrupt contexts) cause a
1426	 deadlock.
1427
1428	 In short, this feature enables the kernel to report locking
1429	 related deadlocks before they actually occur.
1430
1431	 The proof does not depend on how hard and complex a
1432	 deadlock scenario would be to trigger: how many
1433	 participant CPUs, tasks and irq-contexts would be needed
1434	 for it to trigger. The proof also does not depend on
1435	 timing: if a race and a resulting deadlock is possible
1436	 theoretically (no matter how unlikely the race scenario
1437	 is), it will be proven so and will immediately be
1438	 reported by the kernel (once the event is observed that
1439	 makes the deadlock theoretically possible).
1440
1441	 If a deadlock is impossible (i.e. the locking rules, as
1442	 observed by the kernel, are mathematically correct), the
1443	 kernel reports nothing.
1444
1445	 NOTE: this feature can also be enabled for rwlocks, mutexes
1446	 and rwsems - in which case all dependencies between these
1447	 different locking variants are observed and mapped too, and
1448	 the proof of observed correctness is also maintained for an
1449	 arbitrary combination of these separate locking variants.
1450
1451	 For more details, see Documentation/locking/lockdep-design.rst.
1452
1453config PROVE_RAW_LOCK_NESTING
1454	bool "Enable raw_spinlock - spinlock nesting checks" if !ARCH_SUPPORTS_RT
1455	depends on PROVE_LOCKING
1456	default y if ARCH_SUPPORTS_RT
1457	help
1458	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1459	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1460	 not violated.
1461
1462config LOCK_STAT
1463	bool "Lock usage statistics"
1464	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1465	select LOCKDEP
1466	select DEBUG_SPINLOCK
1467	select DEBUG_MUTEXES if !PREEMPT_RT
1468	select DEBUG_RT_MUTEXES if RT_MUTEXES
1469	select DEBUG_LOCK_ALLOC
1470	default n
1471	help
1472	 This feature enables tracking lock contention points
1473
1474	 For more details, see Documentation/locking/lockstat.rst
1475
1476	 This also enables lock events required by "perf lock",
1477	 subcommand of perf.
1478	 If you want to use "perf lock", you also need to turn on
1479	 CONFIG_EVENT_TRACING.
1480
1481	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1482	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1483
1484config DEBUG_RT_MUTEXES
1485	bool "RT Mutex debugging, deadlock detection"
1486	depends on DEBUG_KERNEL && RT_MUTEXES
1487	help
1488	 This allows rt mutex semantics violations and rt mutex related
1489	 deadlocks (lockups) to be detected and reported automatically.
1490
1491config DEBUG_SPINLOCK
1492	bool "Spinlock and rw-lock debugging: basic checks"
1493	depends on DEBUG_KERNEL
1494	select UNINLINE_SPIN_UNLOCK
1495	help
1496	  Say Y here and build SMP to catch missing spinlock initialization
1497	  and certain other kinds of spinlock errors commonly made.  This is
1498	  best used in conjunction with the NMI watchdog so that spinlock
1499	  deadlocks are also debuggable.
1500
1501config DEBUG_MUTEXES
1502	bool "Mutex debugging: basic checks"
1503	depends on DEBUG_KERNEL && !PREEMPT_RT
1504	help
1505	 This feature allows mutex semantics violations to be detected and
1506	 reported.
1507
1508config DEBUG_WW_MUTEX_SLOWPATH
1509	bool "Wait/wound mutex debugging: Slowpath testing"
1510	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1511	select DEBUG_LOCK_ALLOC
1512	select DEBUG_SPINLOCK
1513	select DEBUG_MUTEXES if !PREEMPT_RT
1514	select DEBUG_RT_MUTEXES if PREEMPT_RT
1515	help
1516	 This feature enables slowpath testing for w/w mutex users by
1517	 injecting additional -EDEADLK wound/backoff cases. Together with
1518	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1519	 will test all possible w/w mutex interface abuse with the
1520	 exception of simply not acquiring all the required locks.
1521	 Note that this feature can introduce significant overhead, so
1522	 it really should not be enabled in a production or distro kernel,
1523	 even a debug kernel.  If you are a driver writer, enable it.  If
1524	 you are a distro, do not.
1525
1526config DEBUG_RWSEMS
1527	bool "RW Semaphore debugging: basic checks"
1528	depends on DEBUG_KERNEL && !PREEMPT_RT
1529	help
1530	  This debugging feature allows mismatched rw semaphore locks
1531	  and unlocks to be detected and reported.
1532
1533config DEBUG_LOCK_ALLOC
1534	bool "Lock debugging: detect incorrect freeing of live locks"
1535	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1536	select DEBUG_SPINLOCK
1537	select DEBUG_MUTEXES if !PREEMPT_RT
1538	select DEBUG_RT_MUTEXES if RT_MUTEXES
1539	select LOCKDEP
1540	help
1541	 This feature will check whether any held lock (spinlock, rwlock,
1542	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1543	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1544	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1545	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1546	 held during task exit.
1547
1548config LOCKDEP
1549	bool
1550	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1551	select STACKTRACE
1552	select KALLSYMS
1553	select KALLSYMS_ALL
1554
1555config LOCKDEP_SMALL
1556	bool
1557
1558config LOCKDEP_BITS
1559	int "Size for MAX_LOCKDEP_ENTRIES (as Nth power of 2)"
1560	depends on LOCKDEP && !LOCKDEP_SMALL
1561	range 10 24
1562	default 15
1563	help
1564	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1565
1566config LOCKDEP_CHAINS_BITS
1567	int "Size for MAX_LOCKDEP_CHAINS (as Nth power of 2)"
1568	depends on LOCKDEP && !LOCKDEP_SMALL
1569	range 10 21
1570	default 16
1571	help
1572	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1573
1574config LOCKDEP_STACK_TRACE_BITS
1575	int "Size for MAX_STACK_TRACE_ENTRIES (as Nth power of 2)"
1576	depends on LOCKDEP && !LOCKDEP_SMALL
1577	range 10 26
1578	default 21 if KASAN
1579	default 19
1580	help
1581	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1582
1583	  KASAN significantly increases stack trace consumption because its
1584	  slab tracking interacts with lockdep's dependency validation under
1585	  PREEMPT_FULL, creating a feedback loop.  The higher default when
1586	  KASAN is enabled costs ~12MB extra, which is negligible compared to
1587	  KASAN's own shadow memory overhead.
1588
1589config LOCKDEP_STACK_TRACE_HASH_BITS
1590	int "Size for STACK_TRACE_HASH_SIZE (as Nth power of 2)"
1591	depends on LOCKDEP && !LOCKDEP_SMALL
1592	range 10 26
1593	default 16 if KASAN
1594	default 14
1595	help
1596	  Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1597
1598config LOCKDEP_CIRCULAR_QUEUE_BITS
1599	int "Size for elements in circular_queue struct (as Nth power of 2)"
1600	depends on LOCKDEP
1601	range 10 26
1602	default 12
1603	help
1604	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1605
1606config DEBUG_LOCKDEP
1607	bool "Lock dependency engine debugging"
1608	depends on DEBUG_KERNEL && LOCKDEP
1609	select DEBUG_IRQFLAGS
1610	help
1611	  If you say Y here, the lock dependency engine will do
1612	  additional runtime checks to debug itself, at the price
1613	  of more runtime overhead.
1614
1615config DEBUG_ATOMIC_SLEEP
1616	bool "Sleep inside atomic section checking"
1617	select PREEMPT_COUNT
1618	depends on DEBUG_KERNEL
1619	depends on !ARCH_NO_PREEMPT
1620	help
1621	  If you say Y here, various routines which may sleep will become very
1622	  noisy if they are called inside atomic sections: when a spinlock is
1623	  held, inside an rcu read side critical section, inside preempt disabled
1624	  sections, inside an interrupt, etc...
1625
1626config DEBUG_LOCKING_API_SELFTESTS
1627	bool "Locking API boot-time self-tests"
1628	depends on DEBUG_KERNEL
1629	help
1630	  Say Y here if you want the kernel to run a short self-test during
1631	  bootup. The self-test checks whether common types of locking bugs
1632	  are detected by debugging mechanisms or not. (if you disable
1633	  lock debugging then those bugs won't be detected of course.)
1634	  The following locking APIs are covered: spinlocks, rwlocks,
1635	  mutexes and rwsems.
1636
1637config LOCK_TORTURE_TEST
1638	tristate "torture tests for locking"
1639	depends on DEBUG_KERNEL
1640	select TORTURE_TEST
1641	help
1642	  This option provides a kernel module that runs torture tests
1643	  on kernel locking primitives.  The kernel module may be built
1644	  after the fact on the running kernel to be tested, if desired.
1645
1646	  Say Y here if you want kernel locking-primitive torture tests
1647	  to be built into the kernel.
1648	  Say M if you want these torture tests to build as a module.
1649	  Say N if you are unsure.
1650
1651config WW_MUTEX_SELFTEST
1652	tristate "Wait/wound mutex selftests"
1653	help
1654	  This option provides a kernel module that runs tests on the
1655	  on the struct ww_mutex locking API.
1656
1657	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1658	  with this test harness.
1659
1660	  Say M if you want these self tests to build as a module.
1661	  Say N if you are unsure.
1662
1663config SCF_TORTURE_TEST
1664	tristate "torture tests for smp_call_function*()"
1665	depends on DEBUG_KERNEL
1666	select TORTURE_TEST
1667	help
1668	  This option provides a kernel module that runs torture tests
1669	  on the smp_call_function() family of primitives.  The kernel
1670	  module may be built after the fact on the running kernel to
1671	  be tested, if desired.
1672
1673config CSD_LOCK_WAIT_DEBUG
1674	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1675	depends on DEBUG_KERNEL
1676	depends on SMP
1677	depends on 64BIT
1678	default n
1679	help
1680	  This option enables debug prints when CPUs are slow to respond
1681	  to the smp_call_function*() IPI wrappers.  These debug prints
1682	  include the IPI handler function currently executing (if any)
1683	  and relevant stack traces.
1684
1685config CSD_LOCK_WAIT_DEBUG_DEFAULT
1686	bool "Default csd_lock_wait() debugging on at boot time"
1687	depends on CSD_LOCK_WAIT_DEBUG
1688	depends on 64BIT
1689	default n
1690	help
1691	  This option causes the csdlock_debug= kernel boot parameter to
1692	  default to 1 (basic debugging) instead of 0 (no debugging).
1693
1694endmenu # lock debugging
1695
1696config TRACE_IRQFLAGS
1697	depends on TRACE_IRQFLAGS_SUPPORT
1698	bool
1699	help
1700	  Enables hooks to interrupt enabling and disabling for
1701	  either tracing or lock debugging.
1702
1703config TRACE_IRQFLAGS_NMI
1704	def_bool y
1705	depends on TRACE_IRQFLAGS
1706	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1707
1708config NMI_CHECK_CPU
1709	bool "Debugging for CPUs failing to respond to backtrace requests"
1710	depends on DEBUG_KERNEL
1711	depends on X86
1712	default n
1713	help
1714	  Enables debug prints when a CPU fails to respond to a given
1715	  backtrace NMI.  These prints provide some reasons why a CPU
1716	  might legitimately be failing to respond, for example, if it
1717	  is offline of if ignore_nmis is set.
1718
1719config DEBUG_IRQFLAGS
1720	bool "Debug IRQ flag manipulation"
1721	help
1722	  Enables checks for potentially unsafe enabling or disabling of
1723	  interrupts, such as calling raw_local_irq_restore() when interrupts
1724	  are enabled.
1725
1726config STACKTRACE
1727	bool "Stack backtrace support"
1728	depends on STACKTRACE_SUPPORT
1729	help
1730	  This option causes the kernel to create a /proc/pid/stack for
1731	  every process, showing its current stack trace.
1732	  It is also used by various kernel debugging features that require
1733	  stack trace generation.
1734
1735config DEBUG_KOBJECT
1736	bool "kobject debugging"
1737	depends on DEBUG_KERNEL
1738	help
1739	  If you say Y here, some extra kobject debugging messages will be sent
1740	  to the syslog.
1741
1742config DEBUG_KOBJECT_RELEASE
1743	bool "kobject release debugging"
1744	depends on DEBUG_OBJECTS_TIMERS
1745	help
1746	  kobjects are reference counted objects.  This means that their
1747	  last reference count put is not predictable, and the kobject can
1748	  live on past the point at which a driver decides to drop its
1749	  initial reference to the kobject gained on allocation.  An
1750	  example of this would be a struct device which has just been
1751	  unregistered.
1752
1753	  However, some buggy drivers assume that after such an operation,
1754	  the memory backing the kobject can be immediately freed.  This
1755	  goes completely against the principles of a refcounted object.
1756
1757	  If you say Y here, the kernel will delay the release of kobjects
1758	  on the last reference count to improve the visibility of this
1759	  kind of kobject release bug.
1760
1761config HAVE_DEBUG_BUGVERBOSE
1762	bool
1763
1764menu "Debug kernel data structures"
1765
1766config DEBUG_LIST
1767	bool "Debug linked list manipulation"
1768	depends on DEBUG_KERNEL
1769	select LIST_HARDENED
1770	help
1771	  Enable this to turn on extended checks in the linked-list walking
1772	  routines.
1773
1774	  This option trades better quality error reports for performance, and
1775	  is more suitable for kernel debugging. If you care about performance,
1776	  you should only enable CONFIG_LIST_HARDENED instead.
1777
1778	  If unsure, say N.
1779
1780config DEBUG_PLIST
1781	bool "Debug priority linked list manipulation"
1782	depends on DEBUG_KERNEL
1783	help
1784	  Enable this to turn on extended checks in the priority-ordered
1785	  linked-list (plist) walking routines.  This checks the entire
1786	  list multiple times during each manipulation.
1787
1788	  If unsure, say N.
1789
1790config DEBUG_SG
1791	bool "Debug SG table operations"
1792	depends on DEBUG_KERNEL
1793	help
1794	  Enable this to turn on checks on scatter-gather tables. This can
1795	  help find problems with drivers that do not properly initialize
1796	  their sg tables.
1797
1798	  If unsure, say N.
1799
1800config DEBUG_NOTIFIERS
1801	bool "Debug notifier call chains"
1802	depends on DEBUG_KERNEL
1803	help
1804	  Enable this to turn on sanity checking for notifier call chains.
1805	  This is most useful for kernel developers to make sure that
1806	  modules properly unregister themselves from notifier chains.
1807	  This is a relatively cheap check but if you care about maximum
1808	  performance, say N.
1809
1810config DEBUG_CLOSURES
1811	bool "Debug closures (bcache async widgits)"
1812	depends on CLOSURES
1813	select DEBUG_FS
1814	help
1815	  Keeps all active closures in a linked list and provides a debugfs
1816	  interface to list them, which makes it possible to see asynchronous
1817	  operations that get stuck.
1818
1819config DEBUG_MAPLE_TREE
1820	bool "Debug maple trees"
1821	depends on DEBUG_KERNEL
1822	help
1823	  Enable maple tree debugging information and extra validations.
1824
1825	  If unsure, say N.
1826
1827endmenu
1828
1829source "kernel/rcu/Kconfig.debug"
1830
1831config DEBUG_WQ_FORCE_RR_CPU
1832	bool "Force round-robin CPU selection for unbound work items"
1833	depends on DEBUG_KERNEL
1834	default n
1835	help
1836	  Workqueue used to implicitly guarantee that work items queued
1837	  without explicit CPU specified are put on the local CPU.  This
1838	  guarantee is no longer true and while local CPU is still
1839	  preferred work items may be put on foreign CPUs.  Kernel
1840	  parameter "workqueue.debug_force_rr_cpu" is added to force
1841	  round-robin CPU selection to flush out usages which depend on the
1842	  now broken guarantee.  This config option enables the debug
1843	  feature by default.  When enabled, memory and cache locality will
1844	  be impacted.
1845
1846config CPU_HOTPLUG_STATE_CONTROL
1847	bool "Enable CPU hotplug state control"
1848	depends on DEBUG_KERNEL
1849	depends on HOTPLUG_CPU
1850	default n
1851	help
1852	  Allows to write steps between "offline" and "online" to the CPUs
1853	  sysfs target file so states can be stepped granular. This is a debug
1854	  option for now as the hotplug machinery cannot be stopped and
1855	  restarted at arbitrary points yet.
1856
1857	  Say N if your are unsure.
1858
1859config LATENCYTOP
1860	bool "Latency measuring infrastructure"
1861	depends on DEBUG_KERNEL
1862	depends on STACKTRACE_SUPPORT
1863	depends on PROC_FS
1864	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1865	select KALLSYMS
1866	select KALLSYMS_ALL
1867	select STACKTRACE
1868	select SCHEDSTATS
1869	help
1870	  Enable this option if you want to use the LatencyTOP tool
1871	  to find out which userspace is blocking on what kernel operations.
1872
1873config DEBUG_CGROUP_REF
1874	bool "Disable inlining of cgroup css reference count functions"
1875	depends on DEBUG_KERNEL
1876	depends on CGROUPS
1877	depends on KPROBES
1878	default n
1879	help
1880	  Force cgroup css reference count functions to not be inlined so
1881	  that they can be kprobed for debugging.
1882
1883source "kernel/trace/Kconfig"
1884
1885config PROVIDE_OHCI1394_DMA_INIT
1886	bool "Remote debugging over FireWire early on boot"
1887	depends on PCI && X86
1888	help
1889	  If you want to debug problems which hang or crash the kernel early
1890	  on boot and the crashing machine has a FireWire port, you can use
1891	  this feature to remotely access the memory of the crashed machine
1892	  over FireWire. This employs remote DMA as part of the OHCI1394
1893	  specification which is now the standard for FireWire controllers.
1894
1895	  With remote DMA, you can monitor the printk buffer remotely using
1896	  firescope and access all memory below 4GB using fireproxy from gdb.
1897	  Even controlling a kernel debugger is possible using remote DMA.
1898
1899	  Usage:
1900
1901	  If ohci1394_dma=early is used as boot parameter, it will initialize
1902	  all OHCI1394 controllers which are found in the PCI config space.
1903
1904	  As all changes to the FireWire bus such as enabling and disabling
1905	  devices cause a bus reset and thereby disable remote DMA for all
1906	  devices, be sure to have the cable plugged and FireWire enabled on
1907	  the debugging host before booting the debug target for debugging.
1908
1909	  This code (~1k) is freed after boot. By then, the firewire stack
1910	  in charge of the OHCI-1394 controllers should be used instead.
1911
1912	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1913
1914source "samples/Kconfig"
1915
1916config ARCH_HAS_DEVMEM_IS_ALLOWED
1917	bool
1918
1919config STRICT_DEVMEM
1920	bool "Filter access to /dev/mem"
1921	depends on MMU && DEVMEM
1922	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1923	default y if PPC || X86 || ARM64 || S390
1924	help
1925	  If this option is disabled, you allow userspace (root) access to all
1926	  of memory, including kernel and userspace memory. Accidental
1927	  access to this is obviously disastrous, but specific access can
1928	  be used by people debugging the kernel. Note that with PAT support
1929	  enabled, even in this case there are restrictions on /dev/mem
1930	  use due to the cache aliasing requirements.
1931
1932	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1933	  file only allows userspace access to PCI space and the BIOS code and
1934	  data regions.  This is sufficient for dosemu and X and all common
1935	  users of /dev/mem.
1936
1937	  If in doubt, say Y.
1938
1939config IO_STRICT_DEVMEM
1940	bool "Filter I/O access to /dev/mem"
1941	depends on STRICT_DEVMEM
1942	help
1943	  If this option is disabled, you allow userspace (root) access to all
1944	  io-memory regardless of whether a driver is actively using that
1945	  range.  Accidental access to this is obviously disastrous, but
1946	  specific access can be used by people debugging kernel drivers.
1947
1948	  If this option is switched on, the /dev/mem file only allows
1949	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1950	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1951	  if the driver using a given range cannot be disabled.
1952
1953	  If in doubt, say Y.
1954
1955menu "$(SRCARCH) Debugging"
1956
1957source "arch/$(SRCARCH)/Kconfig.debug"
1958
1959endmenu
1960
1961menu "Kernel Testing and Coverage"
1962
1963source "lib/kunit/Kconfig"
1964
1965config NOTIFIER_ERROR_INJECTION
1966	tristate "Notifier error injection"
1967	depends on DEBUG_KERNEL
1968	select DEBUG_FS
1969	help
1970	  This option provides the ability to inject artificial errors to
1971	  specified notifier chain callbacks. It is useful to test the error
1972	  handling of notifier call chain failures.
1973
1974	  Say N if unsure.
1975
1976config PM_NOTIFIER_ERROR_INJECT
1977	tristate "PM notifier error injection module"
1978	depends on PM && NOTIFIER_ERROR_INJECTION
1979	default m if PM_DEBUG
1980	help
1981	  This option provides the ability to inject artificial errors to
1982	  PM notifier chain callbacks.  It is controlled through debugfs
1983	  interface /sys/kernel/debug/notifier-error-inject/pm
1984
1985	  If the notifier call chain should be failed with some events
1986	  notified, write the error code to "actions/<notifier event>/error".
1987
1988	  Example: Inject PM suspend error (-12 = -ENOMEM)
1989
1990	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1991	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1992	  # echo mem > /sys/power/state
1993	  bash: echo: write error: Cannot allocate memory
1994
1995	  To compile this code as a module, choose M here: the module will
1996	  be called pm-notifier-error-inject.
1997
1998	  If unsure, say N.
1999
2000config OF_RECONFIG_NOTIFIER_ERROR_INJECT
2001	tristate "OF reconfig notifier error injection module"
2002	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
2003	help
2004	  This option provides the ability to inject artificial errors to
2005	  OF reconfig notifier chain callbacks.  It is controlled
2006	  through debugfs interface under
2007	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
2008
2009	  If the notifier call chain should be failed with some events
2010	  notified, write the error code to "actions/<notifier event>/error".
2011
2012	  To compile this code as a module, choose M here: the module will
2013	  be called of-reconfig-notifier-error-inject.
2014
2015	  If unsure, say N.
2016
2017config NETDEV_NOTIFIER_ERROR_INJECT
2018	tristate "Netdev notifier error injection module"
2019	depends on NET && NOTIFIER_ERROR_INJECTION
2020	help
2021	  This option provides the ability to inject artificial errors to
2022	  netdevice notifier chain callbacks.  It is controlled through debugfs
2023	  interface /sys/kernel/debug/notifier-error-inject/netdev
2024
2025	  If the notifier call chain should be failed with some events
2026	  notified, write the error code to "actions/<notifier event>/error".
2027
2028	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
2029
2030	  # cd /sys/kernel/debug/notifier-error-inject/netdev
2031	  # echo -22 > actions/NETDEV_CHANGEMTU/error
2032	  # ip link set eth0 mtu 1024
2033	  RTNETLINK answers: Invalid argument
2034
2035	  To compile this code as a module, choose M here: the module will
2036	  be called netdev-notifier-error-inject.
2037
2038	  If unsure, say N.
2039
2040config FUNCTION_ERROR_INJECTION
2041	bool "Fault-injections of functions"
2042	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
2043	help
2044	  Add fault injections into various functions that are annotated with
2045	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
2046	  value of these functions. This is useful to test error paths of code.
2047
2048	  If unsure, say N
2049
2050config FAULT_INJECTION
2051	bool "Fault-injection framework"
2052	depends on DEBUG_KERNEL
2053	help
2054	  Provide fault-injection framework.
2055	  For more details, see Documentation/fault-injection/.
2056
2057config FAILSLAB
2058	bool "Fault-injection capability for kmalloc"
2059	depends on FAULT_INJECTION
2060	help
2061	  Provide fault-injection capability for kmalloc.
2062
2063config FAIL_PAGE_ALLOC
2064	bool "Fault-injection capability for alloc_pages()"
2065	depends on FAULT_INJECTION
2066	help
2067	  Provide fault-injection capability for alloc_pages().
2068
2069config FAULT_INJECTION_USERCOPY
2070	bool "Fault injection capability for usercopy functions"
2071	depends on FAULT_INJECTION
2072	help
2073	  Provides fault-injection capability to inject failures
2074	  in usercopy functions (copy_from_user(), get_user(), ...).
2075
2076config FAIL_MAKE_REQUEST
2077	bool "Fault-injection capability for disk IO"
2078	depends on FAULT_INJECTION && BLOCK
2079	help
2080	  Provide fault-injection capability for disk IO.
2081
2082config FAIL_IO_TIMEOUT
2083	bool "Fault-injection capability for faking disk interrupts"
2084	depends on FAULT_INJECTION && BLOCK
2085	help
2086	  Provide fault-injection capability on end IO handling. This
2087	  will make the block layer "forget" an interrupt as configured,
2088	  thus exercising the error handling.
2089
2090	  Only works with drivers that use the generic timeout handling,
2091	  for others it won't do anything.
2092
2093config FAIL_FUTEX
2094	bool "Fault-injection capability for futexes"
2095	select DEBUG_FS
2096	depends on FAULT_INJECTION && FUTEX
2097	help
2098	  Provide fault-injection capability for futexes.
2099
2100config FAULT_INJECTION_DEBUG_FS
2101	bool "Debugfs entries for fault-injection capabilities"
2102	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2103	help
2104	  Enable configuration of fault-injection capabilities via debugfs.
2105
2106config FAIL_FUNCTION
2107	bool "Fault-injection capability for functions"
2108	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2109	help
2110	  Provide function-based fault-injection capability.
2111	  This will allow you to override a specific function with a return
2112	  with given return value. As a result, function caller will see
2113	  an error value and have to handle it. This is useful to test the
2114	  error handling in various subsystems.
2115
2116config FAIL_MMC_REQUEST
2117	bool "Fault-injection capability for MMC IO"
2118	depends on FAULT_INJECTION_DEBUG_FS && MMC
2119	help
2120	  Provide fault-injection capability for MMC IO.
2121	  This will make the mmc core return data errors. This is
2122	  useful to test the error handling in the mmc block device
2123	  and to test how the mmc host driver handles retries from
2124	  the block device.
2125
2126config FAIL_SUNRPC
2127	bool "Fault-injection capability for SunRPC"
2128	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2129	help
2130	  Provide fault-injection capability for SunRPC and
2131	  its consumers.
2132
2133config FAIL_SKB_REALLOC
2134	bool "Fault-injection capability forcing skb to reallocate"
2135	depends on FAULT_INJECTION_DEBUG_FS
2136	help
2137	  Provide fault-injection capability that forces the skb to be
2138	  reallocated, catching possible invalid pointers to the skb.
2139
2140	  For more information, check
2141	  Documentation/fault-injection/fault-injection.rst
2142
2143config FAULT_INJECTION_CONFIGFS
2144	bool "Configfs interface for fault-injection capabilities"
2145	depends on FAULT_INJECTION
2146	select CONFIGFS_FS
2147	help
2148	  This option allows configfs-based drivers to dynamically configure
2149	  fault-injection via configfs.  Each parameter for driver-specific
2150	  fault-injection can be made visible as a configfs attribute in a
2151	  configfs group.
2152
2153
2154config FAULT_INJECTION_STACKTRACE_FILTER
2155	bool "stacktrace filter for fault-injection capabilities"
2156	depends on FAULT_INJECTION
2157	depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
2158	select STACKTRACE
2159	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2160	help
2161	  Provide stacktrace filter for fault-injection capabilities
2162
2163config ARCH_HAS_KCOV
2164	bool
2165	help
2166	  An architecture should select this when it can successfully
2167	  build and run with CONFIG_KCOV. This typically requires
2168	  disabling instrumentation for some early boot code.
2169
2170config KCOV
2171	bool "Code coverage for fuzzing"
2172	depends on ARCH_HAS_KCOV
2173	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2174		   GCC_VERSION >= 120000 || CC_IS_CLANG
2175	select DEBUG_FS
2176	select OBJTOOL if HAVE_NOINSTR_HACK
2177	help
2178	  KCOV exposes kernel code coverage information in a form suitable
2179	  for coverage-guided fuzzing (randomized testing).
2180
2181	  For more details, see Documentation/dev-tools/kcov.rst.
2182
2183config KCOV_ENABLE_COMPARISONS
2184	bool "Enable comparison operands collection by KCOV"
2185	depends on KCOV
2186	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2187	help
2188	  KCOV also exposes operands of every comparison in the instrumented
2189	  code along with operand sizes and PCs of the comparison instructions.
2190	  These operands can be used by fuzzing engines to improve the quality
2191	  of fuzzing coverage.
2192
2193config KCOV_INSTRUMENT_ALL
2194	bool "Instrument all code by default"
2195	depends on KCOV
2196	default y
2197	help
2198	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2199	  then you will want to instrument the whole kernel and you should
2200	  say y here. If you are doing more targeted fuzzing (like e.g.
2201	  filesystem fuzzing with AFL) then you will want to enable coverage
2202	  for more specific subsets of files, and should say n here.
2203
2204config KCOV_IRQ_AREA_SIZE
2205	hex "Size of interrupt coverage collection area in words"
2206	depends on KCOV
2207	range 0x80 0x1000000
2208	default 0x40000
2209	help
2210	  KCOV uses preallocated areas to collect coverage from soft
2211	  interrupts. This specifies the size of those areas in the
2212	  number of unsigned long words.
2213
2214config KCOV_SELFTEST
2215	bool "Perform short selftests on boot"
2216	depends on KCOV
2217	help
2218	  Run short KCOV coverage collection selftests on boot.
2219	  On test failure, causes the kernel to panic. Recommended to be
2220	  enabled, ensuring critical functionality works as intended.
2221
2222menuconfig RUNTIME_TESTING_MENU
2223	bool "Runtime Testing"
2224	default y
2225
2226if RUNTIME_TESTING_MENU
2227
2228config TEST_DHRY
2229	tristate "Dhrystone benchmark test"
2230	help
2231	  Enable this to include the Dhrystone 2.1 benchmark.  This test
2232	  calculates the number of Dhrystones per second, and the number of
2233	  DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2234	  by 1757 (the number of Dhrystones per second obtained on the VAX
2235	  11/780, nominally a 1 MIPS machine).
2236
2237	  To run the benchmark, it needs to be enabled explicitly, either from
2238	  the kernel command line (when built-in), or from userspace (when
2239	  built-in or modular).
2240
2241	  Run once during kernel boot:
2242
2243	      test_dhry.run
2244
2245	  Set number of iterations from kernel command line:
2246
2247	      test_dhry.iterations=<n>
2248
2249	  Set number of iterations from userspace:
2250
2251	      echo <n> > /sys/module/test_dhry/parameters/iterations
2252
2253	  Trigger manual run from userspace:
2254
2255	      echo y > /sys/module/test_dhry/parameters/run
2256
2257	  If the number of iterations is <= 0, the test will devise a suitable
2258	  number of iterations (test runs for at least 2s) automatically.
2259	  This process takes ca. 4s.
2260
2261	  If unsure, say N.
2262
2263config LKDTM
2264	tristate "Linux Kernel Dump Test Tool Module"
2265	depends on DEBUG_FS
2266	help
2267	This module enables testing of the different dumping mechanisms by
2268	inducing system failures at predefined crash points.
2269	If you don't need it: say N
2270	Choose M here to compile this code as a module. The module will be
2271	called lkdtm.
2272
2273	Documentation on how to use the module can be found in
2274	Documentation/fault-injection/provoke-crashes.rst
2275
2276config CPUMASK_KUNIT_TEST
2277	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2278	depends on KUNIT
2279	default KUNIT_ALL_TESTS
2280	help
2281	  Enable to turn on cpumask tests, running at boot or module load time.
2282
2283	  For more information on KUnit and unit tests in general, please refer
2284	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2285
2286	  If unsure, say N.
2287
2288config TEST_LIST_SORT
2289	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2290	depends on KUNIT
2291	default KUNIT_ALL_TESTS
2292	help
2293	  Enable this to turn on 'list_sort()' function test. This test is
2294	  executed only once during system boot (so affects only boot time),
2295	  or at module load time.
2296
2297	  If unsure, say N.
2298
2299config TEST_SORT
2300	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2301	depends on KUNIT
2302	default KUNIT_ALL_TESTS
2303	help
2304	  This option enables the self-test function of 'sort()' at boot,
2305	  or at module load time.
2306
2307	  If unsure, say N.
2308
2309config TEST_DIV64
2310	tristate "64bit/32bit division and modulo test"
2311	depends on DEBUG_KERNEL || m
2312	help
2313	  Enable this to turn on 'do_div()' function test. This test is
2314	  executed only once during system boot (so affects only boot time),
2315	  or at module load time.
2316
2317	  If unsure, say N.
2318
2319config TEST_MULDIV64
2320	tristate "mul_u64_u64_div_u64() test"
2321	depends on DEBUG_KERNEL || m
2322	help
2323	  Enable this to turn on 'mul_u64_u64_div_u64()' function test.
2324	  This test is executed only once during system boot (so affects
2325	  only boot time), or at module load time.
2326
2327	  If unsure, say N.
2328
2329config TEST_IOV_ITER
2330	tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS
2331	depends on KUNIT
2332	depends on MMU
2333	default KUNIT_ALL_TESTS
2334	help
2335	  Enable this to turn on testing of the operation of the I/O iterator
2336	  (iov_iter). This test is executed only once during system boot (so
2337	  affects only boot time), or at module load time.
2338
2339	  If unsure, say N.
2340
2341config KPROBES_SANITY_TEST
2342	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2343	depends on DEBUG_KERNEL
2344	depends on KPROBES
2345	depends on KUNIT
2346	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2347	default KUNIT_ALL_TESTS
2348	help
2349	  This option provides for testing basic kprobes functionality on
2350	  boot. Samples of kprobe and kretprobe are inserted and
2351	  verified for functionality.
2352
2353	  Say N if you are unsure.
2354
2355config FPROBE_SANITY_TEST
2356	bool "Self test for fprobe"
2357	depends on DEBUG_KERNEL
2358	depends on FPROBE
2359	depends on KUNIT=y
2360	help
2361	  This option will enable testing the fprobe when the system boot.
2362	  A series of tests are made to verify that the fprobe is functioning
2363	  properly.
2364
2365	  Say N if you are unsure.
2366
2367config BACKTRACE_SELF_TEST
2368	tristate "Self test for the backtrace code"
2369	depends on DEBUG_KERNEL
2370	help
2371	  This option provides a kernel module that can be used to test
2372	  the kernel stack backtrace code. This option is not useful
2373	  for distributions or general kernels, but only for kernel
2374	  developers working on architecture code.
2375
2376	  Note that if you want to also test saved backtraces, you will
2377	  have to enable STACKTRACE as well.
2378
2379	  Say N if you are unsure.
2380
2381config TEST_REF_TRACKER
2382	tristate "Self test for reference tracker"
2383	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2384	select REF_TRACKER
2385	help
2386	  This option provides a kernel module performing tests
2387	  using reference tracker infrastructure.
2388
2389	  Say N if you are unsure.
2390
2391config RBTREE_TEST
2392	tristate "Red-Black tree test"
2393	depends on DEBUG_KERNEL
2394	help
2395	  A benchmark measuring the performance of the rbtree library.
2396	  Also includes rbtree invariant checks.
2397
2398config REED_SOLOMON_TEST
2399	tristate "Reed-Solomon library test"
2400	depends on DEBUG_KERNEL || m
2401	select REED_SOLOMON
2402	select REED_SOLOMON_ENC16
2403	select REED_SOLOMON_DEC16
2404	help
2405	  This option enables the self-test function of rslib at boot,
2406	  or at module load time.
2407
2408	  If unsure, say N.
2409
2410config INTERVAL_TREE_TEST
2411	tristate "Interval tree test"
2412	depends on DEBUG_KERNEL
2413	select INTERVAL_TREE
2414	help
2415	  A benchmark measuring the performance of the interval tree library
2416
2417config PERCPU_TEST
2418	tristate "Per cpu operations test"
2419	depends on m && DEBUG_KERNEL
2420	help
2421	  Enable this option to build test module which validates per-cpu
2422	  operations.
2423
2424	  If unsure, say N.
2425
2426config ATOMIC64_SELFTEST
2427	tristate "Perform an atomic64_t self-test"
2428	help
2429	  Enable this option to test the atomic64_t functions at boot or
2430	  at module load time.
2431
2432	  If unsure, say N.
2433
2434config ASYNC_RAID6_TEST
2435	tristate "Self test for hardware accelerated raid6 recovery"
2436	depends on ASYNC_RAID6_RECOV
2437	select ASYNC_MEMCPY
2438	help
2439	  This is a one-shot self test that permutes through the
2440	  recovery of all the possible two disk failure scenarios for a
2441	  N-disk array.  Recovery is performed with the asynchronous
2442	  raid6 recovery routines, and will optionally use an offload
2443	  engine if one is available.
2444
2445	  If unsure, say N.
2446
2447config TEST_HEXDUMP
2448	tristate "Test functions located in the hexdump module at runtime"
2449
2450config PRINTF_KUNIT_TEST
2451	tristate "KUnit test printf() family of functions at runtime" if !KUNIT_ALL_TESTS
2452	depends on KUNIT
2453	default KUNIT_ALL_TESTS
2454	help
2455	  Enable this option to test the printf functions at runtime.
2456
2457	  If unsure, say N.
2458
2459config SCANF_KUNIT_TEST
2460	tristate "KUnit test scanf() family of functions at runtime" if !KUNIT_ALL_TESTS
2461	depends on KUNIT
2462	default KUNIT_ALL_TESTS
2463	help
2464	  Enable this option to test the scanf functions at runtime.
2465
2466	  If unsure, say N.
2467
2468config SEQ_BUF_KUNIT_TEST
2469	tristate "KUnit test for seq_buf" if !KUNIT_ALL_TESTS
2470	depends on KUNIT
2471	default KUNIT_ALL_TESTS
2472	help
2473	  This builds unit tests for the seq_buf library.
2474
2475	  If unsure, say N.
2476
2477config STRING_KUNIT_TEST
2478	tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS
2479	depends on KUNIT
2480	default KUNIT_ALL_TESTS
2481
2482config STRING_HELPERS_KUNIT_TEST
2483	tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS
2484	depends on KUNIT
2485	default KUNIT_ALL_TESTS
2486
2487config STRING_KUNIT_BENCH
2488       bool "Benchmark string functions at runtime"
2489       depends on STRING_KUNIT_TEST
2490       help
2491         Enable performance measurement for string functions.
2492
2493         This measures the execution efficiency of string functions
2494         during the KUnit test run.
2495
2496         If unsure, say N.
2497
2498config FFS_KUNIT_TEST
2499	tristate "KUnit test ffs-family functions at runtime" if !KUNIT_ALL_TESTS
2500	depends on KUNIT
2501	default KUNIT_ALL_TESTS
2502	help
2503	  This builds KUnit tests for ffs-family bit manipulation functions
2504	  including ffs(), __ffs(), fls(), __fls(), fls64(), and __ffs64().
2505
2506	  These tests validate mathematical correctness, edge case handling,
2507	  and cross-architecture consistency of bit scanning functions.
2508
2509	  For more information on KUnit and unit tests in general,
2510	  please refer to Documentation/dev-tools/kunit/.
2511
2512config TEST_KSTRTOX
2513	tristate "Test kstrto*() family of functions at runtime"
2514
2515config TEST_BITMAP
2516	tristate "Test bitmap_*() family of functions at runtime"
2517	help
2518	  Enable this option to test the bitmap functions at boot.
2519
2520	  If unsure, say N.
2521
2522config TEST_XARRAY
2523	tristate "Test the XArray code at runtime"
2524
2525config TEST_MAPLE_TREE
2526	tristate "Test the Maple Tree code at runtime or module load"
2527	help
2528	  Enable this option to test the maple tree code functions at boot, or
2529	  when the module is loaded. Enable "Debug Maple Trees" will enable
2530	  more verbose output on failures.
2531
2532	  If unsure, say N.
2533
2534config TEST_RHASHTABLE
2535	tristate "Perform selftest on resizable hash table"
2536	help
2537	  Enable this option to test the rhashtable functions at boot.
2538
2539	  If unsure, say N.
2540
2541config TEST_IDA
2542	tristate "Perform selftest on IDA functions"
2543
2544config TEST_MISC_MINOR
2545	bool "miscdevice KUnit test" if !KUNIT_ALL_TESTS
2546	depends on KUNIT=y
2547	default KUNIT_ALL_TESTS
2548	help
2549	  Kunit test for miscdevice API, specially its behavior in respect to
2550	  static and dynamic minor numbers.
2551
2552	  KUnit tests run during boot and output the results to the debug log
2553	  in TAP format (https://testanything.org/). Only useful for kernel devs
2554	  running the KUnit test harness, and not intended for inclusion into a
2555	  production build.
2556
2557	  For more information on KUnit and unit tests in general please refer
2558	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2559
2560	  If unsure, say N.
2561
2562config TEST_PARMAN
2563	tristate "Perform selftest on priority array manager"
2564	depends on PARMAN
2565	help
2566	  Enable this option to test priority array manager on boot
2567	  (or module load).
2568
2569	  If unsure, say N.
2570
2571config TEST_LKM
2572	tristate "Test module loading with 'hello world' module"
2573	depends on m
2574	help
2575	  This builds the "test_module" module that emits "Hello, world"
2576	  on printk when loaded. It is designed to be used for basic
2577	  evaluation of the module loading subsystem (for example when
2578	  validating module verification). It lacks any extra dependencies,
2579	  and will not normally be loaded by the system unless explicitly
2580	  requested by name.
2581
2582	  If unsure, say N.
2583
2584config TEST_BITOPS
2585	tristate "Test module for compilation of bitops operations"
2586	help
2587	  This builds the "test_bitops" module that is much like the
2588	  TEST_LKM module except that it does a basic exercise of the
2589	  set/clear_bit macros and get_count_order/long to make sure there are
2590	  no compiler warnings from C=1 sparse checker or -Wextra
2591	  compilations. It has no dependencies and doesn't run or load unless
2592	  explicitly requested by name.  for example: modprobe test_bitops.
2593
2594	  If unsure, say N.
2595
2596config TEST_VMALLOC
2597	tristate "Test module for stress/performance analysis of vmalloc allocator"
2598	default n
2599	depends on MMU
2600	help
2601	  This builds the "test_vmalloc" module that should be used for
2602	  stress and performance analysis. So, any new change for vmalloc
2603	  subsystem can be evaluated from performance and stability point
2604	  of view.
2605
2606	  If unsure, say N.
2607
2608config TEST_WORKQUEUE
2609	tristate "Test module for stress/performance analysis of workqueue"
2610	depends on m
2611	default n
2612	help
2613	  This builds the "test_workqueue" module for benchmarking
2614	  workqueue throughput under contention. Useful for evaluating
2615	  affinity scope changes (e.g., cache_shard vs cache).
2616
2617	  The test drives sysfs to switch affinity scopes, so it must be
2618	  loaded after userspace has mounted sysfs; building it in (=y)
2619	  would run module_init before /sys is available.
2620
2621	  If unsure, say N.
2622
2623config TEST_BPF
2624	tristate "Test BPF filter functionality"
2625	depends on m && NET
2626	help
2627	  This builds the "test_bpf" module that runs various test vectors
2628	  against the BPF interpreter or BPF JIT compiler depending on the
2629	  current setting. This is in particular useful for BPF JIT compiler
2630	  development, but also to run regression tests against changes in
2631	  the interpreter code. It also enables test stubs for eBPF maps and
2632	  verifier used by user space verifier testsuite.
2633
2634	  If unsure, say N.
2635
2636config FIND_BIT_BENCHMARK
2637	tristate "Test find_bit functions"
2638	help
2639	  This builds the "test_find_bit" module that measure find_*_bit()
2640	  functions performance.
2641
2642	  If unsure, say N.
2643
2644config REGION_ALLOC_BENCHMARK
2645	tristate "Benchmark bitmap, IDA and Maple Tree region allocation"
2646	help
2647	  This builds a microbenchmark comparing variable-sized region
2648	  allocation using bitmaps, IDA and Maple Tree. The benchmark
2649	  runs at initialization time.
2650
2651	  Usage:
2652	    insmod region_alloc_benchmark.ko
2653	    insmod region_alloc_benchmark.ko capacities=1024,2048,4096,65536
2654
2655	  If unsure, say N.
2656
2657config FIND_BIT_BENCHMARK_RUST
2658	tristate "Test find_bit functions in Rust"
2659	depends on RUST
2660	help
2661	  This builds the "find_bit_benchmark_rust" module. It is a micro
2662          benchmark that measures the performance of Rust functions that
2663          correspond to the find_*_bit() operations in C. It follows the
2664          FIND_BIT_BENCHMARK closely but will in general not yield same
2665          numbers due to extra bounds checks and overhead of foreign
2666          function calls.
2667
2668	  If unsure, say N.
2669
2670config TEST_FIRMWARE
2671	tristate "Test firmware loading via userspace interface"
2672	depends on FW_LOADER
2673	help
2674	  This builds the "test_firmware" module that creates a userspace
2675	  interface for testing firmware loading. This can be used to
2676	  control the triggering of firmware loading without needing an
2677	  actual firmware-using device. The contents can be rechecked by
2678	  userspace.
2679
2680	  If unsure, say N.
2681
2682config TEST_SYSCTL
2683	tristate "sysctl test driver"
2684	depends on SYSCTL
2685	help
2686	  This builds the "test_sysctl" module. This driver enables to test the
2687	  proc sysctl interfaces available to drivers safely without affecting
2688	  production knobs which might alter system functionality.
2689
2690	  If unsure, say N.
2691
2692config BITOPS_KUNIT
2693	tristate "KUnit test for bitops" if !KUNIT_ALL_TESTS
2694	depends on KUNIT
2695	default KUNIT_ALL_TESTS
2696	help
2697	  This option enables the KUnit test for the bitops library
2698	  which provides functions for bit operations.
2699
2700	  Note that this is derived from the original test_bitops module.
2701	  For micro-benchmarks and compiler warning checks, enable TEST_BITOPS.
2702
2703	  If unsure, say N.
2704
2705config BITFIELD_KUNIT
2706	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2707	depends on KUNIT
2708	default KUNIT_ALL_TESTS
2709	help
2710	  Enable this option to test the bitfield functions at boot.
2711
2712	  KUnit tests run during boot and output the results to the debug log
2713	  in TAP format (http://testanything.org/). Only useful for kernel devs
2714	  running the KUnit test harness, and not intended for inclusion into a
2715	  production build.
2716
2717	  For more information on KUnit and unit tests in general please refer
2718	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2719
2720	  If unsure, say N.
2721
2722config CHECKSUM_KUNIT
2723	tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2724	depends on KUNIT
2725	default KUNIT_ALL_TESTS
2726	help
2727	  Enable this option to test the checksum functions at boot.
2728
2729	  KUnit tests run during boot and output the results to the debug log
2730	  in TAP format (http://testanything.org/). Only useful for kernel devs
2731	  running the KUnit test harness, and not intended for inclusion into a
2732	  production build.
2733
2734	  For more information on KUnit and unit tests in general please refer
2735	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2736
2737	  If unsure, say N.
2738
2739config UTIL_MACROS_KUNIT
2740	tristate "KUnit test util_macros.h functions at runtime" if !KUNIT_ALL_TESTS
2741	depends on KUNIT
2742	default KUNIT_ALL_TESTS
2743	help
2744	  Enable this option to test the util_macros.h function at boot.
2745
2746	  KUnit tests run during boot and output the results to the debug log
2747	  in TAP format (http://testanything.org/). Only useful for kernel devs
2748	  running the KUnit test harness, and not intended for inclusion into a
2749	  production build.
2750
2751	  For more information on KUnit and unit tests in general please refer
2752	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2753
2754	  If unsure, say N.
2755
2756config HASH_KUNIT_TEST
2757	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2758	depends on KUNIT
2759	default KUNIT_ALL_TESTS
2760	help
2761	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2762	  integer (<linux/hash.h>) hash functions on boot.
2763
2764	  KUnit tests run during boot and output the results to the debug log
2765	  in TAP format (https://testanything.org/). Only useful for kernel devs
2766	  running the KUnit test harness, and not intended for inclusion into a
2767	  production build.
2768
2769	  For more information on KUnit and unit tests in general please refer
2770	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2771
2772	  This is intended to help people writing architecture-specific
2773	  optimized versions. If unsure, say N.
2774
2775config RESOURCE_KUNIT_TEST
2776	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2777	depends on KUNIT
2778	default KUNIT_ALL_TESTS
2779	select GET_FREE_REGION
2780	help
2781	  This builds the resource API unit test.
2782	  Tests the logic of API provided by resource.c and ioport.h.
2783	  For more information on KUnit and unit tests in general please refer
2784	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2785
2786	  If unsure, say N.
2787
2788config SYSCTL_KUNIT_TEST
2789	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2790	depends on KUNIT
2791	default KUNIT_ALL_TESTS
2792	help
2793	  This builds the proc sysctl unit test, which runs on boot.
2794	  Tests the API contract and implementation correctness of sysctl.
2795	  For more information on KUnit and unit tests in general please refer
2796	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2797
2798	  If unsure, say N.
2799
2800config KFIFO_KUNIT_TEST
2801	tristate "KUnit Test for the generic kernel FIFO implementation" if !KUNIT_ALL_TESTS
2802	depends on KUNIT
2803	default KUNIT_ALL_TESTS
2804	help
2805	  This builds the generic FIFO implementation KUnit test suite.
2806	  It tests that the API and basic functionality of the kfifo type
2807	  and associated macros.
2808
2809	  For more information on KUnit and unit tests in general please refer
2810	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2811
2812	  If unsure, say N.
2813
2814config LIST_KUNIT_TEST
2815	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2816	depends on KUNIT
2817	default KUNIT_ALL_TESTS
2818	help
2819	  This builds the linked list KUnit test suite.
2820	  It tests that the API and basic functionality of the list_head type
2821	  and associated macros.
2822
2823	  KUnit tests run during boot and output the results to the debug log
2824	  in TAP format (https://testanything.org/). Only useful for kernel devs
2825	  running the KUnit test harness, and not intended for inclusion into a
2826	  production build.
2827
2828	  For more information on KUnit and unit tests in general please refer
2829	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2830
2831	  If unsure, say N.
2832
2833config LIST_PRIVATE_KUNIT_TEST
2834	tristate "KUnit Test for Kernel Private Linked-list structures" if !KUNIT_ALL_TESTS
2835	depends on KUNIT
2836	default KUNIT_ALL_TESTS
2837	help
2838	  This builds the KUnit test for the private linked-list primitives
2839	  defined in include/linux/list_private.h.
2840
2841	  These primitives allow manipulation of list_head members that are
2842	  marked as private and require special accessors (ACCESS_PRIVATE)
2843	  to strip qualifiers or handle encapsulation.
2844
2845	  If unsure, say N.
2846
2847config HASHTABLE_KUNIT_TEST
2848	tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2849	depends on KUNIT
2850	default KUNIT_ALL_TESTS
2851	help
2852	  This builds the hashtable KUnit test suite.
2853	  It tests the basic functionality of the API defined in
2854	  include/linux/hashtable.h. For more information on KUnit and
2855	  unit tests in general please refer to the KUnit documentation
2856	  in Documentation/dev-tools/kunit/.
2857
2858	  If unsure, say N.
2859
2860config LINEAR_RANGES_TEST
2861	tristate "KUnit test for linear_ranges"
2862	depends on KUNIT
2863	select LINEAR_RANGES
2864	help
2865	  This builds the linear_ranges unit test, which runs on boot.
2866	  Tests the linear_ranges logic correctness.
2867	  For more information on KUnit and unit tests in general please refer
2868	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2869
2870	  If unsure, say N.
2871
2872config CONTEXT_ANALYSIS_TEST
2873	bool "Compiler context-analysis warnings test"
2874	depends on EXPERT
2875	help
2876	  This builds the test for compiler-based context analysis. The test
2877	  does not add executable code to the kernel, but is meant to test that
2878	  common patterns supported by the analysis do not result in false
2879	  positive warnings.
2880
2881	  When adding support for new context locks, it is strongly recommended
2882	  to add supported patterns to this test.
2883
2884	  If unsure, say N.
2885
2886config LIVEUPDATE_TEST
2887	bool "Live Update Kernel Test"
2888	default n
2889	depends on LIVEUPDATE
2890	help
2891	  Enable a built-in kernel test module for the Live Update
2892	  Orchestrator.
2893
2894	  This module validates the File-Lifecycle-Bound subsystem by
2895	  registering a set of mock FLB objects with any real file handlers
2896	  that support live update (such as the memfd handler).
2897
2898	  When live update operations are performed, this test module will
2899	  output messages to the kernel log (dmesg), confirming that its
2900	  registration and various callback functions (preserve, retrieve,
2901	  finish, etc.) are being invoked correctly.
2902
2903	  This is a debugging and regression testing tool for developers
2904	  working on the Live Update subsystem. It should not be enabled in
2905	  production kernels.
2906
2907	  If unsure, say N
2908
2909config CMDLINE_KUNIT_TEST
2910	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2911	depends on KUNIT
2912	default KUNIT_ALL_TESTS
2913	help
2914	  This builds the cmdline API unit test.
2915	  Tests the logic of API provided by cmdline.c.
2916	  For more information on KUnit and unit tests in general please refer
2917	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2918
2919	  If unsure, say N.
2920
2921config BASE64_KUNIT
2922	tristate "KUnit test for base64 decoding and encoding" if !KUNIT_ALL_TESTS
2923	depends on KUNIT
2924	default KUNIT_ALL_TESTS
2925	help
2926	  This builds the base64 unit tests.
2927
2928	  The tests cover the encoding and decoding logic of Base64 functions
2929	  in the kernel.
2930	  In addition to correctness checks, simple performance benchmarks
2931	  for both encoding and decoding are also included.
2932
2933	  For more information on KUnit and unit tests in general please refer
2934	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2935
2936	  If unsure, say N.
2937
2938config BITS_TEST
2939	tristate "KUnit test for bit functions and macros" if !KUNIT_ALL_TESTS
2940	depends on KUNIT
2941	default KUNIT_ALL_TESTS
2942	help
2943	  This builds the bits unit test.
2944	  Tests the logic of macros defined in bits.h.
2945	  For more information on KUnit and unit tests in general please refer
2946	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2947
2948	  If unsure, say N.
2949
2950config SHDI3_KUNIT_TEST
2951	tristate "KUnit test for __ashldi3(), __ashrdi3(), and __lshrdi3()"
2952	depends on KUNIT
2953	depends on ARM || XTENSA || MICROBLAZE || ((RISCV || SPARC) && !64BIT)
2954	help
2955	  This builds the unit test for __ashldi3(), __ashrdi3(), and
2956	  __lshrdi3() helper functions used to implement 64-bit arithmetic
2957	  shift left, arithmetic shift right and logical shift right,
2958	  respectively, on a 32-bit CPUs.
2959
2960config SLUB_KUNIT_TEST
2961	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2962	depends on SLUB_DEBUG && KUNIT
2963	default KUNIT_ALL_TESTS
2964	help
2965	  This builds SLUB allocator unit test.
2966	  Tests SLUB cache debugging functionality.
2967	  For more information on KUnit and unit tests in general please refer
2968	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2969
2970	  If unsure, say N.
2971
2972config RATIONAL_KUNIT_TEST
2973	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2974	depends on KUNIT && RATIONAL
2975	default KUNIT_ALL_TESTS
2976	help
2977	  This builds the rational math unit test.
2978	  For more information on KUnit and unit tests in general please refer
2979	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2980
2981	  If unsure, say N.
2982
2983config MEMCPY_KUNIT_TEST
2984	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2985	depends on KUNIT
2986	default KUNIT_ALL_TESTS
2987	help
2988	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2989	  For more information on KUnit and unit tests in general please refer
2990	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2991
2992	  If unsure, say N.
2993
2994config MIN_HEAP_KUNIT_TEST
2995	tristate "Min heap test" if !KUNIT_ALL_TESTS
2996	depends on KUNIT
2997	default KUNIT_ALL_TESTS
2998	help
2999	  This option enables the KUnit test suite for the min heap library
3000	  which provides functions for creating and managing min heaps.
3001	  The test suite checks the functionality of the min heap library.
3002
3003	  If unsure, say N
3004
3005config IS_SIGNED_TYPE_KUNIT_TEST
3006	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
3007	depends on KUNIT
3008	default KUNIT_ALL_TESTS
3009	help
3010	  Builds unit tests for the is_signed_type() macro.
3011
3012	  For more information on KUnit and unit tests in general please refer
3013	  to the KUnit documentation in Documentation/dev-tools/kunit/.
3014
3015	  If unsure, say N.
3016
3017config OVERFLOW_KUNIT_TEST
3018	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
3019	depends on KUNIT
3020	default KUNIT_ALL_TESTS
3021	help
3022	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
3023	  related functions.
3024
3025	  For more information on KUnit and unit tests in general please refer
3026	  to the KUnit documentation in Documentation/dev-tools/kunit/.
3027
3028	  If unsure, say N.
3029
3030config RANDSTRUCT_KUNIT_TEST
3031	tristate "Test randstruct structure layout randomization at runtime" if !KUNIT_ALL_TESTS
3032	depends on KUNIT
3033	default KUNIT_ALL_TESTS
3034	help
3035	  Builds unit tests for the checking CONFIG_RANDSTRUCT=y, which
3036	  randomizes structure layouts.
3037
3038config STACKINIT_KUNIT_TEST
3039	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
3040	depends on KUNIT
3041	default KUNIT_ALL_TESTS
3042	help
3043	  Test if the kernel is zero-initializing stack variables and
3044	  padding. Coverage is controlled by compiler flags,
3045	  CONFIG_INIT_STACK_ALL_PATTERN or CONFIG_INIT_STACK_ALL_ZERO.
3046
3047config FORTIFY_KUNIT_TEST
3048	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
3049	depends on KUNIT
3050	default KUNIT_ALL_TESTS
3051	help
3052	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
3053	  by the str*() and mem*() family of functions. For testing runtime
3054	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
3055
3056config LONGEST_SYM_KUNIT_TEST
3057	tristate "Test the longest symbol possible" if !KUNIT_ALL_TESTS
3058	depends on KUNIT && KPROBES
3059	depends on !CALL_PADDING && !CFI && !GCOV_KERNEL
3060	default KUNIT_ALL_TESTS
3061	help
3062	  Tests the longest symbol possible
3063
3064	  If unsure, say N.
3065
3066config HW_BREAKPOINT_KUNIT_TEST
3067	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
3068	depends on HAVE_HW_BREAKPOINT
3069	depends on KUNIT=y
3070	default KUNIT_ALL_TESTS
3071	help
3072	  Tests for hw_breakpoint constraints accounting.
3073
3074	  If unsure, say N.
3075
3076source "lib/crypto/tests/Kconfig"
3077
3078config SIPHASH_KUNIT_TEST
3079	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
3080	depends on KUNIT
3081	default KUNIT_ALL_TESTS
3082	help
3083	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
3084	  functions on boot (or module load).
3085
3086	  This is intended to help people writing architecture-specific
3087	  optimized versions.  If unsure, say N.
3088
3089config USERCOPY_KUNIT_TEST
3090	tristate "KUnit Test for user/kernel boundary protections"
3091	depends on KUNIT
3092	default KUNIT_ALL_TESTS
3093	help
3094	  This builds the "usercopy_kunit" module that runs sanity checks
3095	  on the copy_to/from_user infrastructure, making sure basic
3096	  user/kernel boundary testing is working.
3097
3098config BLACKHOLE_DEV_KUNIT_TEST
3099	tristate "Test blackhole netdev functionality" if !KUNIT_ALL_TESTS
3100	depends on NET
3101	depends on KUNIT
3102	default KUNIT_ALL_TESTS
3103	help
3104	  This builds the "blackhole_dev_kunit" module that validates the
3105	  data path through this blackhole netdev.
3106
3107	  If unsure, say N.
3108
3109config TEST_UDELAY
3110	tristate "udelay test driver"
3111	help
3112	  This builds the "udelay_test" module that helps to make sure
3113	  that udelay() is working properly.
3114
3115	  If unsure, say N.
3116
3117config TEST_STATIC_KEYS
3118	tristate "Test static keys"
3119	depends on m
3120	help
3121	  Test the static key interfaces.
3122
3123	  If unsure, say N.
3124
3125config TEST_DYNAMIC_DEBUG
3126	tristate "Test DYNAMIC_DEBUG"
3127	depends on DYNAMIC_DEBUG
3128	help
3129	  This module registers a tracer callback to count enabled
3130	  pr_debugs in a 'do_debugging' function, then alters their
3131	  enablements, calls the function, and compares counts.
3132
3133	  If unsure, say N.
3134
3135config TEST_KMOD
3136	tristate "kmod stress tester"
3137	depends on m
3138	select TEST_LKM
3139	help
3140	  Test the kernel's module loading mechanism: kmod. kmod implements
3141	  support to load modules using the Linux kernel's usermode helper.
3142	  This test provides a series of tests against kmod.
3143
3144	  Although technically you can either build test_kmod as a module or
3145	  into the kernel we disallow building it into the kernel since
3146	  it stress tests request_module() and this will very likely cause
3147	  some issues by taking over precious threads available from other
3148	  module load requests, ultimately this could be fatal.
3149
3150	  To run tests run:
3151
3152	  tools/testing/selftests/kmod/kmod.sh --help
3153
3154	  If unsure, say N.
3155
3156config TEST_RUNTIME
3157	bool
3158
3159config TEST_RUNTIME_MODULE
3160	bool
3161
3162config TEST_KALLSYMS
3163	tristate "module kallsyms find_symbol() test"
3164	depends on m
3165	select TEST_RUNTIME
3166	select TEST_RUNTIME_MODULE
3167	select TEST_KALLSYMS_A
3168	select TEST_KALLSYMS_B
3169	select TEST_KALLSYMS_C
3170	select TEST_KALLSYMS_D
3171	help
3172	  This allows us to stress test find_symbol() through the kallsyms
3173	  used to place symbols on the kernel ELF kallsyms and modules kallsyms
3174	  where we place kernel symbols such as exported symbols.
3175
3176	  We have four test modules:
3177
3178	  A: has KALLSYSMS_NUMSYMS exported symbols
3179	  B: uses one of A's symbols
3180	  C: adds KALLSYMS_SCALE_FACTOR * KALLSYSMS_NUMSYMS exported
3181	  D: adds 2 * the symbols than C
3182
3183	  We stress test find_symbol() through two means:
3184
3185	  1) Upon load of B it will trigger simplify_symbols() to look for the
3186	  one symbol it uses from the module A with tons of symbols. This is an
3187	  indirect way for us to have B call resolve_symbol_wait() upon module
3188	  load. This will eventually call find_symbol() which will eventually
3189	  try to find the symbols used with find_exported_symbol_in_section().
3190	  find_exported_symbol_in_section() uses bsearch() so a binary search
3191	  for each symbol. Binary search will at worst be O(log(n)) so the
3192	  larger TEST_MODULE_KALLSYSMS the worse the search.
3193
3194	  2) The selftests should load C first, before B. Upon B's load towards
3195	  the end right before we call module B's init routine we get
3196	  complete_formation() called on the module. That will first check
3197	  for duplicate symbols with the call to verify_exported_symbols().
3198	  That is when we'll force iteration on module C's insane symbol list.
3199	  Since it has 10 * KALLSYMS_NUMSYMS it means we can first test
3200	  just loading B without C. The amount of time it takes to load C Vs
3201	  B can give us an idea of the impact growth of the symbol space and
3202	  give us projection. Module A only uses one symbol from B so to allow
3203	  this scaling in module C to be proportional, if it used more symbols
3204	  then the first test would be doing more and increasing just the
3205	  search space would be slightly different. The last module, module D
3206	  will just increase the search space by twice the number of symbols in
3207	  C so to allow for full projects.
3208
3209	  tools/testing/selftests/module/find_symbol.sh
3210
3211	  The current defaults will incur a build delay of about 7 minutes
3212	  on an x86_64 with only 8 cores. Enable this only if you want to
3213	  stress test find_symbol() with thousands of symbols. At the same
3214	  time this is also useful to test building modules with thousands of
3215	  symbols, and if BTF is enabled this also stress tests adding BTF
3216	  information for each module. Currently enabling many more symbols
3217	  will segfault the build system.
3218
3219	  If unsure, say N.
3220
3221if TEST_KALLSYMS
3222
3223config TEST_KALLSYMS_A
3224	tristate
3225	depends on m
3226
3227config TEST_KALLSYMS_B
3228	tristate
3229	depends on m
3230
3231config TEST_KALLSYMS_C
3232	tristate
3233	depends on m
3234
3235config TEST_KALLSYMS_D
3236	tristate
3237	depends on m
3238
3239choice
3240	prompt "Kallsym test range"
3241	default TEST_KALLSYMS_LARGE
3242	help
3243	  Selecting something other than "Fast" will enable tests which slow
3244	  down the build and may crash your build.
3245
3246config TEST_KALLSYMS_FAST
3247	bool "Fast builds"
3248	help
3249	  You won't really be testing kallsysms, so this just helps fast builds
3250	  when allmodconfig is used..
3251
3252config TEST_KALLSYMS_LARGE
3253	bool "Enable testing kallsyms with large exports"
3254	help
3255	  This will enable larger number of symbols. This will slow down
3256	  your build considerably.
3257
3258config TEST_KALLSYMS_MAX
3259	bool "Known kallsysms limits"
3260	help
3261	  This will enable exports to the point we know we'll start crashing
3262	  builds.
3263
3264endchoice
3265
3266config TEST_KALLSYMS_NUMSYMS
3267	int "test kallsyms number of symbols"
3268	range 2 10000
3269	default 2 if TEST_KALLSYMS_FAST
3270	default 100 if TEST_KALLSYMS_LARGE
3271	default 10000 if TEST_KALLSYMS_MAX
3272	help
3273	  The number of symbols to create on TEST_KALLSYMS_A, only one of which
3274	  module TEST_KALLSYMS_B will use. This also will be used
3275	  for how many symbols TEST_KALLSYMS_C will have, scaled up by
3276	  TEST_KALLSYMS_SCALE_FACTOR. Note that setting this to 10,000 will
3277	  trigger a segfault today, don't use anything close to it unless
3278	  you are aware that this should not be used for automated build tests.
3279
3280config TEST_KALLSYMS_SCALE_FACTOR
3281	int "test kallsyms scale factor"
3282	default 8
3283	help
3284	  How many more unusued symbols will TEST_KALLSYSMS_C have than
3285	  TEST_KALLSYMS_A. If 8, then module C will have 8 * syms
3286	  than module A. Then TEST_KALLSYMS_D will have double the amount
3287	  of symbols than C so to allow projections.
3288
3289endif # TEST_KALLSYMS
3290
3291config TEST_DEBUG_VIRTUAL
3292	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
3293	depends on DEBUG_VIRTUAL
3294	help
3295	  Test the kernel's ability to detect incorrect calls to
3296	  virt_to_phys() done against the non-linear part of the
3297	  kernel's virtual address map.
3298
3299	  If unsure, say N.
3300
3301config TEST_MEMCAT_P
3302	tristate "Test memcat_p() helper function"
3303	help
3304	  Test the memcat_p() helper for correctly merging two
3305	  pointer arrays together.
3306
3307	  If unsure, say N.
3308
3309config TEST_OBJAGG
3310	tristate "Perform selftest on object aggreration manager"
3311	default n
3312	depends on OBJAGG
3313	help
3314	  Enable this option to test object aggregation manager on boot
3315	  (or module load).
3316
3317config TEST_MEMINIT
3318	tristate "Test heap/page initialization"
3319	help
3320	  Test if the kernel is zero-initializing heap and page allocations.
3321	  This can be useful to test init_on_alloc and init_on_free features.
3322
3323	  If unsure, say N.
3324
3325config TEST_HMM
3326	tristate "Test HMM (Heterogeneous Memory Management)"
3327	depends on TRANSPARENT_HUGEPAGE
3328	depends on DEVICE_PRIVATE
3329	select HMM_MIRROR
3330	select MMU_NOTIFIER
3331	help
3332	  This is a pseudo device driver solely for testing HMM.
3333	  Say M here if you want to build the HMM test module.
3334	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
3335
3336	  If unsure, say N.
3337
3338config TEST_FREE_PAGES
3339	tristate "Test freeing pages"
3340	help
3341	  Test that a memory leak does not occur due to a race between
3342	  freeing a block of pages and a speculative page reference.
3343	  Loading this module is safe if your kernel has the bug fixed.
3344	  If the bug is not fixed, it will leak gigabytes of memory and
3345	  probably OOM your system.
3346
3347config TEST_FPU
3348	tristate "Test floating point operations in kernel space"
3349	depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL
3350	help
3351	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
3352	  which will trigger a sequence of floating point operations. This is used
3353	  for self-testing floating point control register setting in
3354	  kernel_fpu_begin().
3355
3356	  If unsure, say N.
3357
3358config TEST_CLOCKSOURCE_WATCHDOG
3359	tristate "Test clocksource watchdog in kernel space"
3360	depends on CLOCKSOURCE_WATCHDOG
3361	help
3362	  Enable this option to create a kernel module that will trigger
3363	  a test of the clocksource watchdog.  This module may be loaded
3364	  via modprobe or insmod in which case it will run upon being
3365	  loaded, or it may be built in, in which case it will run
3366	  shortly after boot.
3367
3368	  If unsure, say N.
3369
3370config TEST_OBJPOOL
3371	tristate "Test module for correctness and stress of objpool"
3372	default n
3373	depends on m && DEBUG_KERNEL
3374	help
3375	  This builds the "test_objpool" module that should be used for
3376	  correctness verification and concurrent testings of objects
3377	  allocation and reclamation.
3378
3379	  If unsure, say N.
3380
3381config TEST_KEXEC_HANDOVER
3382	bool "Test for Kexec HandOver"
3383	default n
3384	depends on KEXEC_HANDOVER
3385	help
3386	  This option enables test for Kexec HandOver (KHO).
3387	  The test consists of two parts: saving kernel data before kexec and
3388	  restoring the data after kexec and verifying that it was properly
3389	  handed over. This test module creates and saves data on the boot of
3390	  the first kernel and restores and verifies the data on the boot of
3391	  kexec'ed kernel.
3392
3393	  For detailed documentation about KHO, see Documentation/core-api/kho.
3394
3395	  To run the test run:
3396
3397	  tools/testing/selftests/kho/vmtest.sh -h
3398
3399	  If unsure, say N.
3400
3401config RATELIMIT_KUNIT_TEST
3402	tristate "KUnit Test for correctness and stress of ratelimit" if !KUNIT_ALL_TESTS
3403	depends on KUNIT
3404	default KUNIT_ALL_TESTS
3405	help
3406	  This builds the "test_ratelimit" module that should be used
3407	  for correctness verification and concurrent testings of rate
3408	  limiting.
3409
3410	  If unsure, say N.
3411
3412config UUID_KUNIT_TEST
3413	tristate "KUnit test for UUID" if !KUNIT_ALL_TESTS
3414	depends on KUNIT
3415	default KUNIT_ALL_TESTS
3416	help
3417	  This option enables the KUnit test suite for the uuid library,
3418	  which provides functions for generating and parsing UUID and GUID.
3419	  The test suite checks parsing of UUID and GUID strings.
3420
3421	  If unsure, say N.
3422
3423config INT_POW_KUNIT_TEST
3424	tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS
3425	depends on KUNIT
3426	default KUNIT_ALL_TESTS
3427	help
3428	  This option enables the KUnit test suite for the int_pow function,
3429	  which performs integer exponentiation. The test suite is designed to
3430	  verify that the implementation of int_pow correctly computes the power
3431	  of a given base raised to a given exponent.
3432
3433	  Enabling this option will include tests that check various scenarios
3434	  and edge cases to ensure the accuracy and reliability of the exponentiation
3435	  function.
3436
3437	  If unsure, say N
3438
3439config INT_SQRT_KUNIT_TEST
3440	tristate "Integer square root test" if !KUNIT_ALL_TESTS
3441	depends on KUNIT
3442	default KUNIT_ALL_TESTS
3443	help
3444	  This option enables the KUnit test suite for the int_sqrt() function,
3445	  which performs square root calculation. The test suite checks
3446	  various scenarios, including edge cases, to ensure correctness.
3447
3448	  Enabling this option will include tests that check various scenarios
3449	  and edge cases to ensure the accuracy and reliability of the square root
3450	  function.
3451
3452	  If unsure, say N
3453
3454config INT_LOG_KUNIT_TEST
3455        tristate "Integer log (int_log) test" if !KUNIT_ALL_TESTS
3456        depends on KUNIT
3457        default KUNIT_ALL_TESTS
3458        help
3459          This option enables the KUnit test suite for the int_log library, which
3460          provides two functions to compute the integer logarithm in base 2 and
3461          base 10, called respectively as intlog2 and intlog10.
3462
3463          If unsure, say N
3464
3465config GCD_KUNIT_TEST
3466	tristate "Greatest common divisor test" if !KUNIT_ALL_TESTS
3467	depends on KUNIT
3468	default KUNIT_ALL_TESTS
3469	help
3470	  This option enables the KUnit test suite for the gcd() function,
3471	  which computes the greatest common divisor of two numbers.
3472
3473	  This test suite verifies the correctness of gcd() across various
3474	  scenarios, including edge cases.
3475
3476	  If unsure, say N
3477
3478config POLYNOMIAL_KUNIT_TEST
3479	tristate "Polynomial calculation (polynomial_calc) test" if !KUNIT_ALL_TESTS
3480	depends on KUNIT
3481	select POLYNOMIAL
3482	default KUNIT_ALL_TESTS
3483	help
3484	  This option enables the KUnit test suite for the polynomial_calc()
3485	  function, which evaluates integer polynomials using factor
3486	  redistribution to avoid overflow.
3487
3488	  The test suite verifies correctness for constant, linear, and
3489	  quadratic polynomials, negative coefficients, per-step dividers,
3490	  divider_leftover, total_divider scaling, and a real sensor
3491	  N-to-temperature conversion polynomial.
3492
3493	  If unsure, say N
3494
3495config PRIME_NUMBERS_KUNIT_TEST
3496	tristate "Prime number generator test" if !KUNIT_ALL_TESTS
3497	depends on KUNIT
3498	depends on PRIME_NUMBERS
3499	default KUNIT_ALL_TESTS
3500	help
3501	  This option enables the KUnit test suite for the {is,next}_prime_number
3502	  functions.
3503
3504	  Enabling this option will include tests that compare the prime number
3505	  generator functions against a brute force implementation.
3506
3507	  If unsure, say N
3508
3509config GLOB_KUNIT_TEST
3510	tristate "Glob matching test" if !KUNIT_ALL_TESTS
3511	depends on GLOB
3512	depends on KUNIT
3513	default KUNIT_ALL_TESTS
3514	help
3515	  Enable this option to test the glob functions at runtime.
3516
3517	  This test suite verifies the correctness of glob_match() across various
3518	  scenarios, including edge cases.
3519
3520	  If unsure, say N
3521
3522config PRANDOM_KUNIT_TEST
3523	tristate "KUnit test for prandom" if !KUNIT_ALL_TESTS
3524	depends on KUNIT
3525	default KUNIT_ALL_TESTS
3526	help
3527	  Enable this option to test the prandom functions at runtime.
3528
3529	  If unsure, say N
3530
3531endif # RUNTIME_TESTING_MENU
3532
3533config ARCH_USE_MEMTEST
3534	bool
3535	help
3536	  An architecture should select this when it uses early_memtest()
3537	  during boot process.
3538
3539config MEMTEST
3540	bool "Memtest"
3541	depends on ARCH_USE_MEMTEST
3542	help
3543	  This option adds a kernel parameter 'memtest', which allows memtest
3544	  to be set and executed.
3545	        memtest=0, mean disabled; -- default
3546	        memtest=1, mean do 1 test pattern;
3547	        ...
3548	        memtest=17, mean do 17 test patterns.
3549	  If you are unsure how to answer this question, answer N.
3550
3551
3552
3553config HYPERV_TESTING
3554	bool "Microsoft Hyper-V driver testing"
3555	default n
3556	depends on HYPERV && DEBUG_FS
3557	help
3558	  Select this option to enable Hyper-V vmbus testing.
3559
3560endmenu # "Kernel Testing and Coverage"
3561
3562menu "Rust hacking"
3563
3564config RUST_DEBUG_ASSERTIONS
3565	bool "Debug assertions"
3566	depends on RUST
3567	help
3568	  Enables rustc's `-Cdebug-assertions` codegen option.
3569
3570	  This flag lets you turn `cfg(debug_assertions)` conditional
3571	  compilation on or off. This can be used to enable extra debugging
3572	  code in development but not in production. For example, it controls
3573	  the behavior of the standard library's `debug_assert!` macro.
3574
3575	  Note that this will apply to all Rust code, including `core`.
3576
3577	  If unsure, say N.
3578
3579config RUST_OVERFLOW_CHECKS
3580	bool "Overflow checks"
3581	default y
3582	depends on RUST
3583	help
3584	  Enables rustc's `-Coverflow-checks` codegen option.
3585
3586	  This flag allows you to control the behavior of runtime integer
3587	  overflow. When overflow-checks are enabled, a Rust panic will occur
3588	  on overflow.
3589
3590	  Note that this will apply to all Rust code, including `core`.
3591
3592	  If unsure, say Y.
3593
3594config RUST_BUILD_ASSERT_ALLOW
3595	bool "Allow unoptimized build-time assertions"
3596	depends on RUST
3597	help
3598	  Controls how `build_error!` and `build_assert!` are handled during the build.
3599
3600	  If calls to them exist in the binary, it may indicate a violated invariant
3601	  or that the optimizer failed to verify the invariant during compilation.
3602
3603	  This should not happen, thus by default the build is aborted. However,
3604	  as an escape hatch, you can choose Y here to ignore them during build
3605	  and let the check be carried at runtime (with `panic!` being called if
3606	  the check fails).
3607
3608	  If unsure, say N.
3609
3610config RUST_KERNEL_DOCTESTS
3611	bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
3612	depends on RUST && KUNIT=y
3613	default KUNIT_ALL_TESTS
3614	help
3615	  This builds the documentation tests of the `kernel` crate
3616	  as KUnit tests.
3617
3618	  For more information on KUnit and unit tests in general,
3619	  please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
3620
3621	  If unsure, say N.
3622
3623config RUST_INLINE_HELPERS
3624	bool "Inline C helpers into Rust code (EXPERIMENTAL)"
3625	depends on RUST && RUSTC_CLANG_LLVM_COMPATIBLE
3626	depends on EXPERT
3627	depends on ARM64 || X86_64
3628	depends on !UML
3629	help
3630	  Inlines C helpers into Rust code using Link Time Optimization.
3631
3632	  If this option is enabled, C helper functions declared in
3633	  rust/helpers/ are inlined into Rust code, which is helpful for
3634	  performance of Rust code. This requires a matching LLVM version for
3635	  Clang and rustc.
3636
3637	  If you are sure that you're using Clang and rustc with matching LLVM
3638	  versions, say Y. Otherwise say N.
3639
3640endmenu # "Rust"
3641
3642endmenu # Kernel hacking
3643