xref: /openbmc/linux/lib/Kconfig.debug (revision ad10c920)
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 STACKTRACE_BUILD_ID
39	bool "Show build ID information in stacktraces"
40	depends on PRINTK
41	help
42	  Selecting this option adds build ID information for symbols in
43	  stacktraces printed with the printk format '%p[SR]b'.
44
45	  This option is intended for distros where debuginfo is not easily
46	  accessible but can be downloaded given the build ID of the vmlinux or
47	  kernel module where the function is located.
48
49config CONSOLE_LOGLEVEL_DEFAULT
50	int "Default console loglevel (1-15)"
51	range 1 15
52	default "7"
53	help
54	  Default loglevel to determine what will be printed on the console.
55
56	  Setting a default here is equivalent to passing in loglevel=<x> in
57	  the kernel bootargs. loglevel=<x> continues to override whatever
58	  value is specified here as well.
59
60	  Note: This does not affect the log level of un-prefixed printk()
61	  usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
62	  option.
63
64config CONSOLE_LOGLEVEL_QUIET
65	int "quiet console loglevel (1-15)"
66	range 1 15
67	default "4"
68	help
69	  loglevel to use when "quiet" is passed on the kernel commandline.
70
71	  When "quiet" is passed on the kernel commandline this loglevel
72	  will be used as the loglevel. IOW passing "quiet" will be the
73	  equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
74
75config MESSAGE_LOGLEVEL_DEFAULT
76	int "Default message log level (1-7)"
77	range 1 7
78	default "4"
79	help
80	  Default log level for printk statements with no specified priority.
81
82	  This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83	  that are auditing their logs closely may want to set it to a lower
84	  priority.
85
86	  Note: This does not affect what message level gets printed on the console
87	  by default. To change that, use loglevel=<x> in the kernel bootargs,
88	  or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
89
90config BOOT_PRINTK_DELAY
91	bool "Delay each boot printk message by N milliseconds"
92	depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
93	help
94	  This build option allows you to read kernel boot messages
95	  by inserting a short delay after each one.  The delay is
96	  specified in milliseconds on the kernel command line,
97	  using "boot_delay=N".
98
99	  It is likely that you would also need to use "lpj=M" to preset
100	  the "loops per jiffie" value.
101	  See a previous boot log for the "lpj" value to use for your
102	  system, and then set "lpj=M" before setting "boot_delay=N".
103	  NOTE:  Using this option may adversely affect SMP systems.
104	  I.e., processors other than the first one may not boot up.
105	  BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106	  what it believes to be lockup conditions.
107
108config DYNAMIC_DEBUG
109	bool "Enable dynamic printk() support"
110	default n
111	depends on PRINTK
112	depends on (DEBUG_FS || PROC_FS)
113	select DYNAMIC_DEBUG_CORE
114	help
115
116	  Compiles debug level messages into the kernel, which would not
117	  otherwise be available at runtime. These messages can then be
118	  enabled/disabled based on various levels of scope - per source file,
119	  function, module, format string, and line number. This mechanism
120	  implicitly compiles in all pr_debug() and dev_dbg() calls, which
121	  enlarges the kernel text size by about 2%.
122
123	  If a source file is compiled with DEBUG flag set, any
124	  pr_debug() calls in it are enabled by default, but can be
125	  disabled at runtime as below.  Note that DEBUG flag is
126	  turned on by many CONFIG_*DEBUG* options.
127
128	  Usage:
129
130	  Dynamic debugging is controlled via the 'dynamic_debug/control' file,
131	  which is contained in the 'debugfs' filesystem or procfs.
132	  Thus, the debugfs or procfs filesystem must first be mounted before
133	  making use of this feature.
134	  We refer the control file as: <debugfs>/dynamic_debug/control. This
135	  file contains a list of the debug statements that can be enabled. The
136	  format for each line of the file is:
137
138		filename:lineno [module]function flags format
139
140	  filename : source file of the debug statement
141	  lineno : line number of the debug statement
142	  module : module that contains the debug statement
143	  function : function that contains the debug statement
144	  flags : '=p' means the line is turned 'on' for printing
145	  format : the format used for the debug statement
146
147	  From a live system:
148
149		nullarbor:~ # cat <debugfs>/dynamic_debug/control
150		# filename:lineno [module]function flags format
151		fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152		fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153		fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154
155	  Example usage:
156
157		// enable the message at line 1603 of file svcsock.c
158		nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159						<debugfs>/dynamic_debug/control
160
161		// enable all the messages in file svcsock.c
162		nullarbor:~ # echo -n 'file svcsock.c +p' >
163						<debugfs>/dynamic_debug/control
164
165		// enable all the messages in the NFS server module
166		nullarbor:~ # echo -n 'module nfsd +p' >
167						<debugfs>/dynamic_debug/control
168
169		// enable all 12 messages in the function svc_process()
170		nullarbor:~ # echo -n 'func svc_process +p' >
171						<debugfs>/dynamic_debug/control
172
173		// disable all 12 messages in the function svc_process()
174		nullarbor:~ # echo -n 'func svc_process -p' >
175						<debugfs>/dynamic_debug/control
176
177	  See Documentation/admin-guide/dynamic-debug-howto.rst for additional
178	  information.
179
180config DYNAMIC_DEBUG_CORE
181	bool "Enable core function of dynamic debug support"
182	depends on PRINTK
183	depends on (DEBUG_FS || PROC_FS)
184	help
185	  Enable core functional support of dynamic debug. It is useful
186	  when you want to tie dynamic debug to your kernel modules with
187	  DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188	  the case of embedded system where the kernel image size is
189	  sensitive for people.
190
191config SYMBOLIC_ERRNAME
192	bool "Support symbolic error names in printf"
193	default y if PRINTK
194	help
195	  If you say Y here, the kernel's printf implementation will
196	  be able to print symbolic error names such as ENOSPC instead
197	  of the number 28. It makes the kernel image slightly larger
198	  (about 3KB), but can make the kernel logs easier to read.
199
200config DEBUG_BUGVERBOSE
201	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202	depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
203	default y
204	help
205	  Say Y here to make BUG() panics output the file name and line number
206	  of the BUG call as well as the EIP and oops trace.  This aids
207	  debugging but costs about 70-100K of memory.
208
209endmenu # "printk and dmesg options"
210
211config DEBUG_KERNEL
212	bool "Kernel debugging"
213	help
214	  Say Y here if you are developing drivers or trying to debug and
215	  identify kernel problems.
216
217config DEBUG_MISC
218	bool "Miscellaneous debug code"
219	default DEBUG_KERNEL
220	depends on DEBUG_KERNEL
221	help
222	  Say Y here if you need to enable miscellaneous debug code that should
223	  be under a more specific debug option but isn't.
224
225menu "Compile-time checks and compiler options"
226
227config DEBUG_INFO
228	bool
229	help
230	  A kernel debug info option other than "None" has been selected
231	  in the "Debug information" choice below, indicating that debug
232	  information will be generated for build targets.
233
234# Clang is known to generate .{s,u}leb128 with symbol deltas with DWARF5, which
235# some targets may not support: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
236config AS_HAS_NON_CONST_LEB128
237	def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
238
239choice
240	prompt "Debug information"
241	depends on DEBUG_KERNEL
242	help
243	  Selecting something other than "None" results in a kernel image
244	  that will include debugging info resulting in a larger kernel image.
245	  This adds debug symbols to the kernel and modules (gcc -g), and
246	  is needed if you intend to use kernel crashdump or binary object
247	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
248
249	  Choose which version of DWARF debug info to emit. If unsure,
250	  select "Toolchain default".
251
252config DEBUG_INFO_NONE
253	bool "Disable debug information"
254	help
255	  Do not build the kernel with debugging information, which will
256	  result in a faster and smaller build.
257
258config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
259	bool "Rely on the toolchain's implicit default DWARF version"
260	select DEBUG_INFO
261	depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
262	help
263	  The implicit default version of DWARF debug info produced by a
264	  toolchain changes over time.
265
266	  This can break consumers of the debug info that haven't upgraded to
267	  support newer revisions, and prevent testing newer versions, but
268	  those should be less common scenarios.
269
270config DEBUG_INFO_DWARF4
271	bool "Generate DWARF Version 4 debuginfo"
272	select DEBUG_INFO
273	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
274	help
275	  Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
276	  if using clang without clang's integrated assembler, and gdb 7.0+.
277
278	  If you have consumers of DWARF debug info that are not ready for
279	  newer revisions of DWARF, you may wish to choose this or have your
280	  config select this.
281
282config DEBUG_INFO_DWARF5
283	bool "Generate DWARF Version 5 debuginfo"
284	select DEBUG_INFO
285	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
286	help
287	  Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
288	  5.0+ accepts the -gdwarf-5 flag but only had partial support for some
289	  draft features until 7.0), and gdb 8.0+.
290
291	  Changes to the structure of debug info in Version 5 allow for around
292	  15-18% savings in resulting image and debug info section sizes as
293	  compared to DWARF Version 4. DWARF Version 5 standardizes previous
294	  extensions such as accelerators for symbol indexing and the format
295	  for fission (.dwo/.dwp) files. Users may not want to select this
296	  config if they rely on tooling that has not yet been updated to
297	  support DWARF Version 5.
298
299endchoice # "Debug information"
300
301if DEBUG_INFO
302
303config DEBUG_INFO_REDUCED
304	bool "Reduce debugging information"
305	help
306	  If you say Y here gcc is instructed to generate less debugging
307	  information for structure types. This means that tools that
308	  need full debugging information (like kgdb or systemtap) won't
309	  be happy. But if you merely need debugging information to
310	  resolve line numbers there is no loss. Advantage is that
311	  build directory object sizes shrink dramatically over a full
312	  DEBUG_INFO build and compile times are reduced too.
313	  Only works with newer gcc versions.
314
315choice
316	prompt "Compressed Debug information"
317	help
318	  Compress the resulting debug info. Results in smaller debug info sections,
319	  but requires that consumers are able to decompress the results.
320
321	  If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
322
323config DEBUG_INFO_COMPRESSED_NONE
324	bool "Don't compress debug information"
325	help
326	  Don't compress debug info sections.
327
328config DEBUG_INFO_COMPRESSED_ZLIB
329	bool "Compress debugging information with zlib"
330	depends on $(cc-option,-gz=zlib)
331	depends on $(ld-option,--compress-debug-sections=zlib)
332	help
333	  Compress the debug information using zlib.  Requires GCC 5.0+ or Clang
334	  5.0+, binutils 2.26+, and zlib.
335
336	  Users of dpkg-deb via scripts/package/builddeb may find an increase in
337	  size of their debug .deb packages with this config set, due to the
338	  debug info being compressed with zlib, then the object files being
339	  recompressed with a different compression scheme. But this is still
340	  preferable to setting $KDEB_COMPRESS to "none" which would be even
341	  larger.
342
343config DEBUG_INFO_COMPRESSED_ZSTD
344	bool "Compress debugging information with zstd"
345	depends on $(cc-option,-gz=zstd)
346	depends on $(ld-option,--compress-debug-sections=zstd)
347	help
348	  Compress the debug information using zstd.  This may provide better
349	  compression than zlib, for about the same time costs, but requires newer
350	  toolchain support.  Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
351	  zstd.
352
353endchoice # "Compressed Debug information"
354
355config DEBUG_INFO_SPLIT
356	bool "Produce split debuginfo in .dwo files"
357	depends on $(cc-option,-gsplit-dwarf)
358	help
359	  Generate debug info into separate .dwo files. This significantly
360	  reduces the build directory size for builds with DEBUG_INFO,
361	  because it stores the information only once on disk in .dwo
362	  files instead of multiple times in object files and executables.
363	  In addition the debug information is also compressed.
364
365	  Requires recent gcc (4.7+) and recent gdb/binutils.
366	  Any tool that packages or reads debug information would need
367	  to know about the .dwo files and include them.
368	  Incompatible with older versions of ccache.
369
370config DEBUG_INFO_BTF
371	bool "Generate BTF typeinfo"
372	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
373	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
374	depends on BPF_SYSCALL
375	depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
376	help
377	  Generate deduplicated BTF type information from DWARF debug info.
378	  Turning this on expects presence of pahole tool, which will convert
379	  DWARF type info into equivalent deduplicated BTF type info.
380
381config PAHOLE_HAS_SPLIT_BTF
382	def_bool PAHOLE_VERSION >= 119
383
384config PAHOLE_HAS_BTF_TAG
385	def_bool PAHOLE_VERSION >= 123
386	depends on CC_IS_CLANG
387	help
388	  Decide whether pahole emits btf_tag attributes (btf_type_tag and
389	  btf_decl_tag) or not. Currently only clang compiler implements
390	  these attributes, so make the config depend on CC_IS_CLANG.
391
392config DEBUG_INFO_BTF_MODULES
393	def_bool y
394	depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
395	help
396	  Generate compact split BTF type information for kernel modules.
397
398config MODULE_ALLOW_BTF_MISMATCH
399	bool "Allow loading modules with non-matching BTF type info"
400	depends on DEBUG_INFO_BTF_MODULES
401	help
402	  For modules whose split BTF does not match vmlinux, load without
403	  BTF rather than refusing to load. The default behavior with
404	  module BTF enabled is to reject modules with such mismatches;
405	  this option will still load module BTF where possible but ignore
406	  it when a mismatch is found.
407
408config GDB_SCRIPTS
409	bool "Provide GDB scripts for kernel debugging"
410	help
411	  This creates the required links to GDB helper scripts in the
412	  build directory. If you load vmlinux into gdb, the helper
413	  scripts will be automatically imported by gdb as well, and
414	  additional functions are available to analyze a Linux kernel
415	  instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
416	  for further details.
417
418endif # DEBUG_INFO
419
420config FRAME_WARN
421	int "Warn for stack frames larger than"
422	range 0 8192
423	default 0 if KMSAN
424	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
425	default 2048 if PARISC
426	default 1536 if (!64BIT && XTENSA)
427	default 1280 if KASAN && !64BIT
428	default 1024 if !64BIT
429	default 2048 if 64BIT
430	help
431	  Tell the compiler to warn at build time for stack frames larger than this.
432	  Setting this too low will cause a lot of warnings.
433	  Setting it to 0 disables the warning.
434
435config STRIP_ASM_SYMS
436	bool "Strip assembler-generated symbols during link"
437	default n
438	help
439	  Strip internal assembler-generated symbols during a link (symbols
440	  that look like '.Lxxx') so they don't pollute the output of
441	  get_wchan() and suchlike.
442
443config READABLE_ASM
444	bool "Generate readable assembler code"
445	depends on DEBUG_KERNEL
446	depends on CC_IS_GCC
447	help
448	  Disable some compiler optimizations that tend to generate human unreadable
449	  assembler output. This may make the kernel slightly slower, but it helps
450	  to keep kernel developers who have to stare a lot at assembler listings
451	  sane.
452
453config HEADERS_INSTALL
454	bool "Install uapi headers to usr/include"
455	depends on !UML
456	help
457	  This option will install uapi headers (headers exported to user-space)
458	  into the usr/include directory for use during the kernel build.
459	  This is unneeded for building the kernel itself, but needed for some
460	  user-space program samples. It is also needed by some features such
461	  as uapi header sanity checks.
462
463config DEBUG_SECTION_MISMATCH
464	bool "Enable full Section mismatch analysis"
465	depends on CC_IS_GCC
466	help
467	  The section mismatch analysis checks if there are illegal
468	  references from one section to another section.
469	  During linktime or runtime, some sections are dropped;
470	  any use of code/data previously in these sections would
471	  most likely result in an oops.
472	  In the code, functions and variables are annotated with
473	  __init,, etc. (see the full list in include/linux/init.h),
474	  which results in the code/data being placed in specific sections.
475	  The section mismatch analysis is always performed after a full
476	  kernel build, and enabling this option causes the following
477	  additional step to occur:
478	  - Add the option -fno-inline-functions-called-once to gcc commands.
479	    When inlining a function annotated with __init in a non-init
480	    function, we would lose the section information and thus
481	    the analysis would not catch the illegal reference.
482	    This option tells gcc to inline less (but it does result in
483	    a larger kernel).
484
485config SECTION_MISMATCH_WARN_ONLY
486	bool "Make section mismatch errors non-fatal"
487	default y
488	help
489	  If you say N here, the build process will fail if there are any
490	  section mismatch, instead of just throwing warnings.
491
492	  If unsure, say Y.
493
494config DEBUG_FORCE_FUNCTION_ALIGN_64B
495	bool "Force all function address 64B aligned"
496	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
497	select FUNCTION_ALIGNMENT_64B
498	help
499	  There are cases that a commit from one domain changes the function
500	  address alignment of other domains, and cause magic performance
501	  bump (regression or improvement). Enable this option will help to
502	  verify if the bump is caused by function alignment changes, while
503	  it will slightly increase the kernel size and affect icache usage.
504
505	  It is mainly for debug and performance tuning use.
506
507#
508# Select this config option from the architecture Kconfig, if it
509# is preferred to always offer frame pointers as a config
510# option on the architecture (regardless of KERNEL_DEBUG):
511#
512config ARCH_WANT_FRAME_POINTERS
513	bool
514
515config FRAME_POINTER
516	bool "Compile the kernel with frame pointers"
517	depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
518	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
519	help
520	  If you say Y here the resulting kernel image will be slightly
521	  larger and slower, but it gives very useful debugging information
522	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
523
524config OBJTOOL
525	bool
526
527config STACK_VALIDATION
528	bool "Compile-time stack metadata validation"
529	depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
530	select OBJTOOL
531	default n
532	help
533	  Validate frame pointer rules at compile-time.  This helps ensure that
534	  runtime stack traces are more reliable.
535
536	  For more information, see
537	  tools/objtool/Documentation/objtool.txt.
538
539config NOINSTR_VALIDATION
540	bool
541	depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
542	select OBJTOOL
543	default y
544
545config VMLINUX_MAP
546	bool "Generate vmlinux.map file when linking"
547	depends on EXPERT
548	help
549	  Selecting this option will pass "-Map=vmlinux.map" to ld
550	  when linking vmlinux. That file can be useful for verifying
551	  and debugging magic section games, and for seeing which
552	  pieces of code get eliminated with
553	  CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
554
555config DEBUG_FORCE_WEAK_PER_CPU
556	bool "Force weak per-cpu definitions"
557	depends on DEBUG_KERNEL
558	help
559	  s390 and alpha require percpu variables in modules to be
560	  defined weak to work around addressing range issue which
561	  puts the following two restrictions on percpu variable
562	  definitions.
563
564	  1. percpu symbols must be unique whether static or not
565	  2. percpu variables can't be defined inside a function
566
567	  To ensure that generic code follows the above rules, this
568	  option forces all percpu variables to be defined as weak.
569
570endmenu # "Compiler options"
571
572menu "Generic Kernel Debugging Instruments"
573
574config MAGIC_SYSRQ
575	bool "Magic SysRq key"
576	depends on !UML
577	help
578	  If you say Y here, you will have some control over the system even
579	  if the system crashes for example during kernel debugging (e.g., you
580	  will be able to flush the buffer cache to disk, reboot the system
581	  immediately or dump some status information). This is accomplished
582	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
583	  also works on a serial console (on PC hardware at least), if you
584	  send a BREAK and then within 5 seconds a command keypress. The
585	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
586	  Don't say Y unless you really know what this hack does.
587
588config MAGIC_SYSRQ_DEFAULT_ENABLE
589	hex "Enable magic SysRq key functions by default"
590	depends on MAGIC_SYSRQ
591	default 0x1
592	help
593	  Specifies which SysRq key functions are enabled by default.
594	  This may be set to 1 or 0 to enable or disable them all, or
595	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
596
597config MAGIC_SYSRQ_SERIAL
598	bool "Enable magic SysRq key over serial"
599	depends on MAGIC_SYSRQ
600	default y
601	help
602	  Many embedded boards have a disconnected TTL level serial which can
603	  generate some garbage that can lead to spurious false sysrq detects.
604	  This option allows you to decide whether you want to enable the
605	  magic SysRq key.
606
607config MAGIC_SYSRQ_SERIAL_SEQUENCE
608	string "Char sequence that enables magic SysRq over serial"
609	depends on MAGIC_SYSRQ_SERIAL
610	default ""
611	help
612	  Specifies a sequence of characters that can follow BREAK to enable
613	  SysRq on a serial console.
614
615	  If unsure, leave an empty string and the option will not be enabled.
616
617config DEBUG_FS
618	bool "Debug Filesystem"
619	help
620	  debugfs is a virtual file system that kernel developers use to put
621	  debugging files into.  Enable this option to be able to read and
622	  write to these files.
623
624	  For detailed documentation on the debugfs API, see
625	  Documentation/filesystems/.
626
627	  If unsure, say N.
628
629choice
630	prompt "Debugfs default access"
631	depends on DEBUG_FS
632	default DEBUG_FS_ALLOW_ALL
633	help
634	  This selects the default access restrictions for debugfs.
635	  It can be overridden with kernel command line option
636	  debugfs=[on,no-mount,off]. The restrictions apply for API access
637	  and filesystem registration.
638
639config DEBUG_FS_ALLOW_ALL
640	bool "Access normal"
641	help
642	  No restrictions apply. Both API and filesystem registration
643	  is on. This is the normal default operation.
644
645config DEBUG_FS_DISALLOW_MOUNT
646	bool "Do not register debugfs as filesystem"
647	help
648	  The API is open but filesystem is not loaded. Clients can still do
649	  their work and read with debug tools that do not need
650	  debugfs filesystem.
651
652config DEBUG_FS_ALLOW_NONE
653	bool "No access"
654	help
655	  Access is off. Clients get -PERM when trying to create nodes in
656	  debugfs tree and debugfs is not registered as a filesystem.
657	  Client can then back-off or continue without debugfs access.
658
659endchoice
660
661source "lib/Kconfig.kgdb"
662source "lib/Kconfig.ubsan"
663source "lib/Kconfig.kcsan"
664
665endmenu
666
667menu "Networking Debugging"
668
669source "net/Kconfig.debug"
670
671endmenu # "Networking Debugging"
672
673menu "Memory Debugging"
674
675source "mm/Kconfig.debug"
676
677config DEBUG_OBJECTS
678	bool "Debug object operations"
679	depends on DEBUG_KERNEL
680	help
681	  If you say Y here, additional code will be inserted into the
682	  kernel to track the life time of various objects and validate
683	  the operations on those objects.
684
685config DEBUG_OBJECTS_SELFTEST
686	bool "Debug objects selftest"
687	depends on DEBUG_OBJECTS
688	help
689	  This enables the selftest of the object debug code.
690
691config DEBUG_OBJECTS_FREE
692	bool "Debug objects in freed memory"
693	depends on DEBUG_OBJECTS
694	help
695	  This enables checks whether a k/v free operation frees an area
696	  which contains an object which has not been deactivated
697	  properly. This can make kmalloc/kfree-intensive workloads
698	  much slower.
699
700config DEBUG_OBJECTS_TIMERS
701	bool "Debug timer objects"
702	depends on DEBUG_OBJECTS
703	help
704	  If you say Y here, additional code will be inserted into the
705	  timer routines to track the life time of timer objects and
706	  validate the timer operations.
707
708config DEBUG_OBJECTS_WORK
709	bool "Debug work objects"
710	depends on DEBUG_OBJECTS
711	help
712	  If you say Y here, additional code will be inserted into the
713	  work queue routines to track the life time of work objects and
714	  validate the work operations.
715
716config DEBUG_OBJECTS_RCU_HEAD
717	bool "Debug RCU callbacks objects"
718	depends on DEBUG_OBJECTS
719	help
720	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
721
722config DEBUG_OBJECTS_PERCPU_COUNTER
723	bool "Debug percpu counter objects"
724	depends on DEBUG_OBJECTS
725	help
726	  If you say Y here, additional code will be inserted into the
727	  percpu counter routines to track the life time of percpu counter
728	  objects and validate the percpu counter operations.
729
730config DEBUG_OBJECTS_ENABLE_DEFAULT
731	int "debug_objects bootup default value (0-1)"
732	range 0 1
733	default "1"
734	depends on DEBUG_OBJECTS
735	help
736	  Debug objects boot parameter default value
737
738config SHRINKER_DEBUG
739	bool "Enable shrinker debugging support"
740	depends on DEBUG_FS
741	help
742	  Say Y to enable the shrinker debugfs interface which provides
743	  visibility into the kernel memory shrinkers subsystem.
744	  Disable it to avoid an extra memory footprint.
745
746config HAVE_DEBUG_KMEMLEAK
747	bool
748
749config DEBUG_KMEMLEAK
750	bool "Kernel memory leak detector"
751	depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
752	select DEBUG_FS
753	select STACKTRACE if STACKTRACE_SUPPORT
754	select KALLSYMS
755	select CRC32
756	select STACKDEPOT
757	select STACKDEPOT_ALWAYS_INIT if !DEBUG_KMEMLEAK_DEFAULT_OFF
758	help
759	  Say Y here if you want to enable the memory leak
760	  detector. The memory allocation/freeing is traced in a way
761	  similar to the Boehm's conservative garbage collector, the
762	  difference being that the orphan objects are not freed but
763	  only shown in /sys/kernel/debug/kmemleak. Enabling this
764	  feature will introduce an overhead to memory
765	  allocations. See Documentation/dev-tools/kmemleak.rst for more
766	  details.
767
768	  Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
769	  of finding leaks due to the slab objects poisoning.
770
771	  In order to access the kmemleak file, debugfs needs to be
772	  mounted (usually at /sys/kernel/debug).
773
774config DEBUG_KMEMLEAK_MEM_POOL_SIZE
775	int "Kmemleak memory pool size"
776	depends on DEBUG_KMEMLEAK
777	range 200 1000000
778	default 16000
779	help
780	  Kmemleak must track all the memory allocations to avoid
781	  reporting false positives. Since memory may be allocated or
782	  freed before kmemleak is fully initialised, use a static pool
783	  of metadata objects to track such callbacks. After kmemleak is
784	  fully initialised, this memory pool acts as an emergency one
785	  if slab allocations fail.
786
787config DEBUG_KMEMLEAK_TEST
788	tristate "Simple test for the kernel memory leak detector"
789	depends on DEBUG_KMEMLEAK && m
790	help
791	  This option enables a module that explicitly leaks memory.
792
793	  If unsure, say N.
794
795config DEBUG_KMEMLEAK_DEFAULT_OFF
796	bool "Default kmemleak to off"
797	depends on DEBUG_KMEMLEAK
798	help
799	  Say Y here to disable kmemleak by default. It can then be enabled
800	  on the command line via kmemleak=on.
801
802config DEBUG_KMEMLEAK_AUTO_SCAN
803	bool "Enable kmemleak auto scan thread on boot up"
804	default y
805	depends on DEBUG_KMEMLEAK
806	help
807	  Depending on the cpu, kmemleak scan may be cpu intensive and can
808	  stall user tasks at times. This option enables/disables automatic
809	  kmemleak scan at boot up.
810
811	  Say N here to disable kmemleak auto scan thread to stop automatic
812	  scanning. Disabling this option disables automatic reporting of
813	  memory leaks.
814
815	  If unsure, say Y.
816
817config DEBUG_STACK_USAGE
818	bool "Stack utilization instrumentation"
819	depends on DEBUG_KERNEL && !IA64
820	help
821	  Enables the display of the minimum amount of free stack which each
822	  task has ever had available in the sysrq-T and sysrq-P debug output.
823
824	  This option will slow down process creation somewhat.
825
826config SCHED_STACK_END_CHECK
827	bool "Detect stack corruption on calls to schedule()"
828	depends on DEBUG_KERNEL
829	default n
830	help
831	  This option checks for a stack overrun on calls to schedule().
832	  If the stack end location is found to be over written always panic as
833	  the content of the corrupted region can no longer be trusted.
834	  This is to ensure no erroneous behaviour occurs which could result in
835	  data corruption or a sporadic crash at a later stage once the region
836	  is examined. The runtime overhead introduced is minimal.
837
838config ARCH_HAS_DEBUG_VM_PGTABLE
839	bool
840	help
841	  An architecture should select this when it can successfully
842	  build and run DEBUG_VM_PGTABLE.
843
844config DEBUG_VM_IRQSOFF
845	def_bool DEBUG_VM && !PREEMPT_RT
846
847config DEBUG_VM
848	bool "Debug VM"
849	depends on DEBUG_KERNEL
850	help
851	  Enable this to turn on extended checks in the virtual-memory system
852	  that may impact performance.
853
854	  If unsure, say N.
855
856config DEBUG_VM_MAPLE_TREE
857	bool "Debug VM maple trees"
858	depends on DEBUG_VM
859	select DEBUG_MAPLE_TREE
860	help
861	  Enable VM maple tree debugging information and extra validations.
862
863	  If unsure, say N.
864
865config DEBUG_VM_RB
866	bool "Debug VM red-black trees"
867	depends on DEBUG_VM
868	help
869	  Enable VM red-black tree debugging information and extra validations.
870
871	  If unsure, say N.
872
873config DEBUG_VM_PGFLAGS
874	bool "Debug page-flags operations"
875	depends on DEBUG_VM
876	help
877	  Enables extra validation on page flags operations.
878
879	  If unsure, say N.
880
881config DEBUG_VM_PGTABLE
882	bool "Debug arch page table for semantics compliance"
883	depends on MMU
884	depends on ARCH_HAS_DEBUG_VM_PGTABLE
885	default y if DEBUG_VM
886	help
887	  This option provides a debug method which can be used to test
888	  architecture page table helper functions on various platforms in
889	  verifying if they comply with expected generic MM semantics. This
890	  will help architecture code in making sure that any changes or
891	  new additions of these helpers still conform to expected
892	  semantics of the generic MM. Platforms will have to opt in for
893	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
894
895	  If unsure, say N.
896
897config ARCH_HAS_DEBUG_VIRTUAL
898	bool
899
900config DEBUG_VIRTUAL
901	bool "Debug VM translations"
902	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
903	help
904	  Enable some costly sanity checks in virtual to page code. This can
905	  catch mistakes with virt_to_page() and friends.
906
907	  If unsure, say N.
908
909config DEBUG_NOMMU_REGIONS
910	bool "Debug the global anon/private NOMMU mapping region tree"
911	depends on DEBUG_KERNEL && !MMU
912	help
913	  This option causes the global tree of anonymous and private mapping
914	  regions to be regularly checked for invalid topology.
915
916config DEBUG_MEMORY_INIT
917	bool "Debug memory initialisation" if EXPERT
918	default !EXPERT
919	help
920	  Enable this for additional checks during memory initialisation.
921	  The sanity checks verify aspects of the VM such as the memory model
922	  and other information provided by the architecture. Verbose
923	  information will be printed at KERN_DEBUG loglevel depending
924	  on the mminit_loglevel= command-line option.
925
926	  If unsure, say Y
927
928config MEMORY_NOTIFIER_ERROR_INJECT
929	tristate "Memory hotplug notifier error injection module"
930	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
931	help
932	  This option provides the ability to inject artificial errors to
933	  memory hotplug notifier chain callbacks.  It is controlled through
934	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
935
936	  If the notifier call chain should be failed with some events
937	  notified, write the error code to "actions/<notifier event>/error".
938
939	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
940
941	  # cd /sys/kernel/debug/notifier-error-inject/memory
942	  # echo -12 > actions/MEM_GOING_OFFLINE/error
943	  # echo offline > /sys/devices/system/memory/memoryXXX/state
944	  bash: echo: write error: Cannot allocate memory
945
946	  To compile this code as a module, choose M here: the module will
947	  be called memory-notifier-error-inject.
948
949	  If unsure, say N.
950
951config DEBUG_PER_CPU_MAPS
952	bool "Debug access to per_cpu maps"
953	depends on DEBUG_KERNEL
954	depends on SMP
955	help
956	  Say Y to verify that the per_cpu map being accessed has
957	  been set up. This adds a fair amount of code to kernel memory
958	  and decreases performance.
959
960	  Say N if unsure.
961
962config DEBUG_KMAP_LOCAL
963	bool "Debug kmap_local temporary mappings"
964	depends on DEBUG_KERNEL && KMAP_LOCAL
965	help
966	  This option enables additional error checking for the kmap_local
967	  infrastructure.  Disable for production use.
968
969config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
970	bool
971
972config DEBUG_KMAP_LOCAL_FORCE_MAP
973	bool "Enforce kmap_local temporary mappings"
974	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
975	select KMAP_LOCAL
976	select DEBUG_KMAP_LOCAL
977	help
978	  This option enforces temporary mappings through the kmap_local
979	  mechanism for non-highmem pages and on non-highmem systems.
980	  Disable this for production systems!
981
982config DEBUG_HIGHMEM
983	bool "Highmem debugging"
984	depends on DEBUG_KERNEL && HIGHMEM
985	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
986	select DEBUG_KMAP_LOCAL
987	help
988	  This option enables additional error checking for high memory
989	  systems.  Disable for production systems.
990
991config HAVE_DEBUG_STACKOVERFLOW
992	bool
993
994config DEBUG_STACKOVERFLOW
995	bool "Check for stack overflows"
996	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
997	help
998	  Say Y here if you want to check for overflows of kernel, IRQ
999	  and exception stacks (if your architecture uses them). This
1000	  option will show detailed messages if free stack space drops
1001	  below a certain limit.
1002
1003	  These kinds of bugs usually occur when call-chains in the
1004	  kernel get too deep, especially when interrupts are
1005	  involved.
1006
1007	  Use this in cases where you see apparently random memory
1008	  corruption, especially if it appears in 'struct thread_info'
1009
1010	  If in doubt, say "N".
1011
1012source "lib/Kconfig.kasan"
1013source "lib/Kconfig.kfence"
1014source "lib/Kconfig.kmsan"
1015
1016endmenu # "Memory Debugging"
1017
1018config DEBUG_SHIRQ
1019	bool "Debug shared IRQ handlers"
1020	depends on DEBUG_KERNEL
1021	help
1022	  Enable this to generate a spurious interrupt just before a shared
1023	  interrupt handler is deregistered (generating one when registering
1024	  is currently disabled). Drivers need to handle this correctly. Some
1025	  don't and need to be caught.
1026
1027menu "Debug Oops, Lockups and Hangs"
1028
1029config PANIC_ON_OOPS
1030	bool "Panic on Oops"
1031	help
1032	  Say Y here to enable the kernel to panic when it oopses. This
1033	  has the same effect as setting oops=panic on the kernel command
1034	  line.
1035
1036	  This feature is useful to ensure that the kernel does not do
1037	  anything erroneous after an oops which could result in data
1038	  corruption or other issues.
1039
1040	  Say N if unsure.
1041
1042config PANIC_ON_OOPS_VALUE
1043	int
1044	range 0 1
1045	default 0 if !PANIC_ON_OOPS
1046	default 1 if PANIC_ON_OOPS
1047
1048config PANIC_TIMEOUT
1049	int "panic timeout"
1050	default 0
1051	help
1052	  Set the timeout value (in seconds) until a reboot occurs when
1053	  the kernel panics. If n = 0, then we wait forever. A timeout
1054	  value n > 0 will wait n seconds before rebooting, while a timeout
1055	  value n < 0 will reboot immediately.
1056
1057config LOCKUP_DETECTOR
1058	bool
1059
1060config SOFTLOCKUP_DETECTOR
1061	bool "Detect Soft Lockups"
1062	depends on DEBUG_KERNEL && !S390
1063	select LOCKUP_DETECTOR
1064	help
1065	  Say Y here to enable the kernel to act as a watchdog to detect
1066	  soft lockups.
1067
1068	  Softlockups are bugs that cause the kernel to loop in kernel
1069	  mode for more than 20 seconds, without giving other tasks a
1070	  chance to run.  The current stack trace is displayed upon
1071	  detection and the system will stay locked up.
1072
1073config BOOTPARAM_SOFTLOCKUP_PANIC
1074	bool "Panic (Reboot) On Soft Lockups"
1075	depends on SOFTLOCKUP_DETECTOR
1076	help
1077	  Say Y here to enable the kernel to panic on "soft lockups",
1078	  which are bugs that cause the kernel to loop in kernel
1079	  mode for more than 20 seconds (configurable using the watchdog_thresh
1080	  sysctl), without giving other tasks a chance to run.
1081
1082	  The panic can be used in combination with panic_timeout,
1083	  to cause the system to reboot automatically after a
1084	  lockup has been detected. This feature is useful for
1085	  high-availability systems that have uptime guarantees and
1086	  where a lockup must be resolved ASAP.
1087
1088	  Say N if unsure.
1089
1090config HARDLOCKUP_DETECTOR_PERF
1091	bool
1092	select SOFTLOCKUP_DETECTOR
1093
1094#
1095# Enables a timestamp based low pass filter to compensate for perf based
1096# hard lockup detection which runs too fast due to turbo modes.
1097#
1098config HARDLOCKUP_CHECK_TIMESTAMP
1099	bool
1100
1101#
1102# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1103# lockup detector rather than the perf based detector.
1104#
1105config HARDLOCKUP_DETECTOR
1106	bool "Detect Hard Lockups"
1107	depends on DEBUG_KERNEL && !S390
1108	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1109	select LOCKUP_DETECTOR
1110	select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1111	help
1112	  Say Y here to enable the kernel to act as a watchdog to detect
1113	  hard lockups.
1114
1115	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1116	  for more than 10 seconds, without letting other interrupts have a
1117	  chance to run.  The current stack trace is displayed upon detection
1118	  and the system will stay locked up.
1119
1120config BOOTPARAM_HARDLOCKUP_PANIC
1121	bool "Panic (Reboot) On Hard Lockups"
1122	depends on HARDLOCKUP_DETECTOR
1123	help
1124	  Say Y here to enable the kernel to panic on "hard lockups",
1125	  which are bugs that cause the kernel to loop in kernel
1126	  mode with interrupts disabled for more than 10 seconds (configurable
1127	  using the watchdog_thresh sysctl).
1128
1129	  Say N if unsure.
1130
1131config DETECT_HUNG_TASK
1132	bool "Detect Hung Tasks"
1133	depends on DEBUG_KERNEL
1134	default SOFTLOCKUP_DETECTOR
1135	help
1136	  Say Y here to enable the kernel to detect "hung tasks",
1137	  which are bugs that cause the task to be stuck in
1138	  uninterruptible "D" state indefinitely.
1139
1140	  When a hung task is detected, the kernel will print the
1141	  current stack trace (which you should report), but the
1142	  task will stay in uninterruptible state. If lockdep is
1143	  enabled then all held locks will also be reported. This
1144	  feature has negligible overhead.
1145
1146config DEFAULT_HUNG_TASK_TIMEOUT
1147	int "Default timeout for hung task detection (in seconds)"
1148	depends on DETECT_HUNG_TASK
1149	default 120
1150	help
1151	  This option controls the default timeout (in seconds) used
1152	  to determine when a task has become non-responsive and should
1153	  be considered hung.
1154
1155	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1156	  sysctl or by writing a value to
1157	  /proc/sys/kernel/hung_task_timeout_secs.
1158
1159	  A timeout of 0 disables the check.  The default is two minutes.
1160	  Keeping the default should be fine in most cases.
1161
1162config BOOTPARAM_HUNG_TASK_PANIC
1163	bool "Panic (Reboot) On Hung Tasks"
1164	depends on DETECT_HUNG_TASK
1165	help
1166	  Say Y here to enable the kernel to panic on "hung tasks",
1167	  which are bugs that cause the kernel to leave a task stuck
1168	  in uninterruptible "D" state.
1169
1170	  The panic can be used in combination with panic_timeout,
1171	  to cause the system to reboot automatically after a
1172	  hung task has been detected. This feature is useful for
1173	  high-availability systems that have uptime guarantees and
1174	  where a hung tasks must be resolved ASAP.
1175
1176	  Say N if unsure.
1177
1178config WQ_WATCHDOG
1179	bool "Detect Workqueue Stalls"
1180	depends on DEBUG_KERNEL
1181	help
1182	  Say Y here to enable stall detection on workqueues.  If a
1183	  worker pool doesn't make forward progress on a pending work
1184	  item for over a given amount of time, 30s by default, a
1185	  warning message is printed along with dump of workqueue
1186	  state.  This can be configured through kernel parameter
1187	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1188
1189config TEST_LOCKUP
1190	tristate "Test module to generate lockups"
1191	depends on m
1192	help
1193	  This builds the "test_lockup" module that helps to make sure
1194	  that watchdogs and lockup detectors are working properly.
1195
1196	  Depending on module parameters it could emulate soft or hard
1197	  lockup, "hung task", or locking arbitrary lock for a long time.
1198	  Also it could generate series of lockups with cooling-down periods.
1199
1200	  If unsure, say N.
1201
1202endmenu # "Debug lockups and hangs"
1203
1204menu "Scheduler Debugging"
1205
1206config SCHED_DEBUG
1207	bool "Collect scheduler debugging info"
1208	depends on DEBUG_KERNEL && PROC_FS
1209	default y
1210	help
1211	  If you say Y here, the /sys/kernel/debug/sched file will be provided
1212	  that can help debug the scheduler. The runtime overhead of this
1213	  option is minimal.
1214
1215config SCHED_INFO
1216	bool
1217	default n
1218
1219config SCHEDSTATS
1220	bool "Collect scheduler statistics"
1221	depends on DEBUG_KERNEL && PROC_FS
1222	select SCHED_INFO
1223	help
1224	  If you say Y here, additional code will be inserted into the
1225	  scheduler and related routines to collect statistics about
1226	  scheduler behavior and provide them in /proc/schedstat.  These
1227	  stats may be useful for both tuning and debugging the scheduler
1228	  If you aren't debugging the scheduler or trying to tune a specific
1229	  application, you can say N to avoid the very slight overhead
1230	  this adds.
1231
1232endmenu
1233
1234config DEBUG_TIMEKEEPING
1235	bool "Enable extra timekeeping sanity checking"
1236	help
1237	  This option will enable additional timekeeping sanity checks
1238	  which may be helpful when diagnosing issues where timekeeping
1239	  problems are suspected.
1240
1241	  This may include checks in the timekeeping hotpaths, so this
1242	  option may have a (very small) performance impact to some
1243	  workloads.
1244
1245	  If unsure, say N.
1246
1247config DEBUG_PREEMPT
1248	bool "Debug preemptible kernel"
1249	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1250	default y
1251	help
1252	  If you say Y here then the kernel will use a debug variant of the
1253	  commonly used smp_processor_id() function and will print warnings
1254	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1255	  will detect preemption count underflows.
1256
1257menu "Lock Debugging (spinlocks, mutexes, etc...)"
1258
1259config LOCK_DEBUGGING_SUPPORT
1260	bool
1261	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1262	default y
1263
1264config PROVE_LOCKING
1265	bool "Lock debugging: prove locking correctness"
1266	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1267	select LOCKDEP
1268	select DEBUG_SPINLOCK
1269	select DEBUG_MUTEXES if !PREEMPT_RT
1270	select DEBUG_RT_MUTEXES if RT_MUTEXES
1271	select DEBUG_RWSEMS
1272	select DEBUG_WW_MUTEX_SLOWPATH
1273	select DEBUG_LOCK_ALLOC
1274	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1275	select TRACE_IRQFLAGS
1276	default n
1277	help
1278	 This feature enables the kernel to prove that all locking
1279	 that occurs in the kernel runtime is mathematically
1280	 correct: that under no circumstance could an arbitrary (and
1281	 not yet triggered) combination of observed locking
1282	 sequences (on an arbitrary number of CPUs, running an
1283	 arbitrary number of tasks and interrupt contexts) cause a
1284	 deadlock.
1285
1286	 In short, this feature enables the kernel to report locking
1287	 related deadlocks before they actually occur.
1288
1289	 The proof does not depend on how hard and complex a
1290	 deadlock scenario would be to trigger: how many
1291	 participant CPUs, tasks and irq-contexts would be needed
1292	 for it to trigger. The proof also does not depend on
1293	 timing: if a race and a resulting deadlock is possible
1294	 theoretically (no matter how unlikely the race scenario
1295	 is), it will be proven so and will immediately be
1296	 reported by the kernel (once the event is observed that
1297	 makes the deadlock theoretically possible).
1298
1299	 If a deadlock is impossible (i.e. the locking rules, as
1300	 observed by the kernel, are mathematically correct), the
1301	 kernel reports nothing.
1302
1303	 NOTE: this feature can also be enabled for rwlocks, mutexes
1304	 and rwsems - in which case all dependencies between these
1305	 different locking variants are observed and mapped too, and
1306	 the proof of observed correctness is also maintained for an
1307	 arbitrary combination of these separate locking variants.
1308
1309	 For more details, see Documentation/locking/lockdep-design.rst.
1310
1311config PROVE_RAW_LOCK_NESTING
1312	bool "Enable raw_spinlock - spinlock nesting checks"
1313	depends on PROVE_LOCKING
1314	default n
1315	help
1316	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1317	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1318	 not violated.
1319
1320	 NOTE: There are known nesting problems. So if you enable this
1321	 option expect lockdep splats until these problems have been fully
1322	 addressed which is work in progress. This config switch allows to
1323	 identify and analyze these problems. It will be removed and the
1324	 check permanently enabled once the main issues have been fixed.
1325
1326	 If unsure, select N.
1327
1328config LOCK_STAT
1329	bool "Lock usage statistics"
1330	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1331	select LOCKDEP
1332	select DEBUG_SPINLOCK
1333	select DEBUG_MUTEXES if !PREEMPT_RT
1334	select DEBUG_RT_MUTEXES if RT_MUTEXES
1335	select DEBUG_LOCK_ALLOC
1336	default n
1337	help
1338	 This feature enables tracking lock contention points
1339
1340	 For more details, see Documentation/locking/lockstat.rst
1341
1342	 This also enables lock events required by "perf lock",
1343	 subcommand of perf.
1344	 If you want to use "perf lock", you also need to turn on
1345	 CONFIG_EVENT_TRACING.
1346
1347	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1348	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1349
1350config DEBUG_RT_MUTEXES
1351	bool "RT Mutex debugging, deadlock detection"
1352	depends on DEBUG_KERNEL && RT_MUTEXES
1353	help
1354	 This allows rt mutex semantics violations and rt mutex related
1355	 deadlocks (lockups) to be detected and reported automatically.
1356
1357config DEBUG_SPINLOCK
1358	bool "Spinlock and rw-lock debugging: basic checks"
1359	depends on DEBUG_KERNEL
1360	select UNINLINE_SPIN_UNLOCK
1361	help
1362	  Say Y here and build SMP to catch missing spinlock initialization
1363	  and certain other kinds of spinlock errors commonly made.  This is
1364	  best used in conjunction with the NMI watchdog so that spinlock
1365	  deadlocks are also debuggable.
1366
1367config DEBUG_MUTEXES
1368	bool "Mutex debugging: basic checks"
1369	depends on DEBUG_KERNEL && !PREEMPT_RT
1370	help
1371	 This feature allows mutex semantics violations to be detected and
1372	 reported.
1373
1374config DEBUG_WW_MUTEX_SLOWPATH
1375	bool "Wait/wound mutex debugging: Slowpath testing"
1376	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1377	select DEBUG_LOCK_ALLOC
1378	select DEBUG_SPINLOCK
1379	select DEBUG_MUTEXES if !PREEMPT_RT
1380	select DEBUG_RT_MUTEXES if PREEMPT_RT
1381	help
1382	 This feature enables slowpath testing for w/w mutex users by
1383	 injecting additional -EDEADLK wound/backoff cases. Together with
1384	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1385	 will test all possible w/w mutex interface abuse with the
1386	 exception of simply not acquiring all the required locks.
1387	 Note that this feature can introduce significant overhead, so
1388	 it really should not be enabled in a production or distro kernel,
1389	 even a debug kernel.  If you are a driver writer, enable it.  If
1390	 you are a distro, do not.
1391
1392config DEBUG_RWSEMS
1393	bool "RW Semaphore debugging: basic checks"
1394	depends on DEBUG_KERNEL
1395	help
1396	  This debugging feature allows mismatched rw semaphore locks
1397	  and unlocks to be detected and reported.
1398
1399config DEBUG_LOCK_ALLOC
1400	bool "Lock debugging: detect incorrect freeing of live locks"
1401	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1402	select DEBUG_SPINLOCK
1403	select DEBUG_MUTEXES if !PREEMPT_RT
1404	select DEBUG_RT_MUTEXES if RT_MUTEXES
1405	select LOCKDEP
1406	help
1407	 This feature will check whether any held lock (spinlock, rwlock,
1408	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1409	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1410	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1411	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1412	 held during task exit.
1413
1414config LOCKDEP
1415	bool
1416	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1417	select STACKTRACE
1418	select KALLSYMS
1419	select KALLSYMS_ALL
1420
1421config LOCKDEP_SMALL
1422	bool
1423
1424config LOCKDEP_BITS
1425	int "Bitsize for MAX_LOCKDEP_ENTRIES"
1426	depends on LOCKDEP && !LOCKDEP_SMALL
1427	range 10 30
1428	default 15
1429	help
1430	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1431
1432config LOCKDEP_CHAINS_BITS
1433	int "Bitsize for MAX_LOCKDEP_CHAINS"
1434	depends on LOCKDEP && !LOCKDEP_SMALL
1435	range 10 30
1436	default 16
1437	help
1438	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1439
1440config LOCKDEP_STACK_TRACE_BITS
1441	int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1442	depends on LOCKDEP && !LOCKDEP_SMALL
1443	range 10 30
1444	default 19
1445	help
1446	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1447
1448config LOCKDEP_STACK_TRACE_HASH_BITS
1449	int "Bitsize for STACK_TRACE_HASH_SIZE"
1450	depends on LOCKDEP && !LOCKDEP_SMALL
1451	range 10 30
1452	default 14
1453	help
1454	  Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1455
1456config LOCKDEP_CIRCULAR_QUEUE_BITS
1457	int "Bitsize for elements in circular_queue struct"
1458	depends on LOCKDEP
1459	range 10 30
1460	default 12
1461	help
1462	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1463
1464config DEBUG_LOCKDEP
1465	bool "Lock dependency engine debugging"
1466	depends on DEBUG_KERNEL && LOCKDEP
1467	select DEBUG_IRQFLAGS
1468	help
1469	  If you say Y here, the lock dependency engine will do
1470	  additional runtime checks to debug itself, at the price
1471	  of more runtime overhead.
1472
1473config DEBUG_ATOMIC_SLEEP
1474	bool "Sleep inside atomic section checking"
1475	select PREEMPT_COUNT
1476	depends on DEBUG_KERNEL
1477	depends on !ARCH_NO_PREEMPT
1478	help
1479	  If you say Y here, various routines which may sleep will become very
1480	  noisy if they are called inside atomic sections: when a spinlock is
1481	  held, inside an rcu read side critical section, inside preempt disabled
1482	  sections, inside an interrupt, etc...
1483
1484config DEBUG_LOCKING_API_SELFTESTS
1485	bool "Locking API boot-time self-tests"
1486	depends on DEBUG_KERNEL
1487	help
1488	  Say Y here if you want the kernel to run a short self-test during
1489	  bootup. The self-test checks whether common types of locking bugs
1490	  are detected by debugging mechanisms or not. (if you disable
1491	  lock debugging then those bugs won't be detected of course.)
1492	  The following locking APIs are covered: spinlocks, rwlocks,
1493	  mutexes and rwsems.
1494
1495config LOCK_TORTURE_TEST
1496	tristate "torture tests for locking"
1497	depends on DEBUG_KERNEL
1498	select TORTURE_TEST
1499	help
1500	  This option provides a kernel module that runs torture tests
1501	  on kernel locking primitives.  The kernel module may be built
1502	  after the fact on the running kernel to be tested, if desired.
1503
1504	  Say Y here if you want kernel locking-primitive torture tests
1505	  to be built into the kernel.
1506	  Say M if you want these torture tests to build as a module.
1507	  Say N if you are unsure.
1508
1509config WW_MUTEX_SELFTEST
1510	tristate "Wait/wound mutex selftests"
1511	help
1512	  This option provides a kernel module that runs tests on the
1513	  on the struct ww_mutex locking API.
1514
1515	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1516	  with this test harness.
1517
1518	  Say M if you want these self tests to build as a module.
1519	  Say N if you are unsure.
1520
1521config SCF_TORTURE_TEST
1522	tristate "torture tests for smp_call_function*()"
1523	depends on DEBUG_KERNEL
1524	select TORTURE_TEST
1525	help
1526	  This option provides a kernel module that runs torture tests
1527	  on the smp_call_function() family of primitives.  The kernel
1528	  module may be built after the fact on the running kernel to
1529	  be tested, if desired.
1530
1531config CSD_LOCK_WAIT_DEBUG
1532	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1533	depends on DEBUG_KERNEL
1534	depends on 64BIT
1535	default n
1536	help
1537	  This option enables debug prints when CPUs are slow to respond
1538	  to the smp_call_function*() IPI wrappers.  These debug prints
1539	  include the IPI handler function currently executing (if any)
1540	  and relevant stack traces.
1541
1542endmenu # lock debugging
1543
1544config TRACE_IRQFLAGS
1545	depends on TRACE_IRQFLAGS_SUPPORT
1546	bool
1547	help
1548	  Enables hooks to interrupt enabling and disabling for
1549	  either tracing or lock debugging.
1550
1551config TRACE_IRQFLAGS_NMI
1552	def_bool y
1553	depends on TRACE_IRQFLAGS
1554	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1555
1556config DEBUG_IRQFLAGS
1557	bool "Debug IRQ flag manipulation"
1558	help
1559	  Enables checks for potentially unsafe enabling or disabling of
1560	  interrupts, such as calling raw_local_irq_restore() when interrupts
1561	  are enabled.
1562
1563config STACKTRACE
1564	bool "Stack backtrace support"
1565	depends on STACKTRACE_SUPPORT
1566	help
1567	  This option causes the kernel to create a /proc/pid/stack for
1568	  every process, showing its current stack trace.
1569	  It is also used by various kernel debugging features that require
1570	  stack trace generation.
1571
1572config WARN_ALL_UNSEEDED_RANDOM
1573	bool "Warn for all uses of unseeded randomness"
1574	default n
1575	help
1576	  Some parts of the kernel contain bugs relating to their use of
1577	  cryptographically secure random numbers before it's actually possible
1578	  to generate those numbers securely. This setting ensures that these
1579	  flaws don't go unnoticed, by enabling a message, should this ever
1580	  occur. This will allow people with obscure setups to know when things
1581	  are going wrong, so that they might contact developers about fixing
1582	  it.
1583
1584	  Unfortunately, on some models of some architectures getting
1585	  a fully seeded CRNG is extremely difficult, and so this can
1586	  result in dmesg getting spammed for a surprisingly long
1587	  time.  This is really bad from a security perspective, and
1588	  so architecture maintainers really need to do what they can
1589	  to get the CRNG seeded sooner after the system is booted.
1590	  However, since users cannot do anything actionable to
1591	  address this, by default this option is disabled.
1592
1593	  Say Y here if you want to receive warnings for all uses of
1594	  unseeded randomness.  This will be of use primarily for
1595	  those developers interested in improving the security of
1596	  Linux kernels running on their architecture (or
1597	  subarchitecture).
1598
1599config DEBUG_KOBJECT
1600	bool "kobject debugging"
1601	depends on DEBUG_KERNEL
1602	help
1603	  If you say Y here, some extra kobject debugging messages will be sent
1604	  to the syslog.
1605
1606config DEBUG_KOBJECT_RELEASE
1607	bool "kobject release debugging"
1608	depends on DEBUG_OBJECTS_TIMERS
1609	help
1610	  kobjects are reference counted objects.  This means that their
1611	  last reference count put is not predictable, and the kobject can
1612	  live on past the point at which a driver decides to drop its
1613	  initial reference to the kobject gained on allocation.  An
1614	  example of this would be a struct device which has just been
1615	  unregistered.
1616
1617	  However, some buggy drivers assume that after such an operation,
1618	  the memory backing the kobject can be immediately freed.  This
1619	  goes completely against the principles of a refcounted object.
1620
1621	  If you say Y here, the kernel will delay the release of kobjects
1622	  on the last reference count to improve the visibility of this
1623	  kind of kobject release bug.
1624
1625config HAVE_DEBUG_BUGVERBOSE
1626	bool
1627
1628menu "Debug kernel data structures"
1629
1630config DEBUG_LIST
1631	bool "Debug linked list manipulation"
1632	depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1633	help
1634	  Enable this to turn on extended checks in the linked-list
1635	  walking routines.
1636
1637	  If unsure, say N.
1638
1639config DEBUG_PLIST
1640	bool "Debug priority linked list manipulation"
1641	depends on DEBUG_KERNEL
1642	help
1643	  Enable this to turn on extended checks in the priority-ordered
1644	  linked-list (plist) walking routines.  This checks the entire
1645	  list multiple times during each manipulation.
1646
1647	  If unsure, say N.
1648
1649config DEBUG_SG
1650	bool "Debug SG table operations"
1651	depends on DEBUG_KERNEL
1652	help
1653	  Enable this to turn on checks on scatter-gather tables. This can
1654	  help find problems with drivers that do not properly initialize
1655	  their sg tables.
1656
1657	  If unsure, say N.
1658
1659config DEBUG_NOTIFIERS
1660	bool "Debug notifier call chains"
1661	depends on DEBUG_KERNEL
1662	help
1663	  Enable this to turn on sanity checking for notifier call chains.
1664	  This is most useful for kernel developers to make sure that
1665	  modules properly unregister themselves from notifier chains.
1666	  This is a relatively cheap check but if you care about maximum
1667	  performance, say N.
1668
1669config BUG_ON_DATA_CORRUPTION
1670	bool "Trigger a BUG when data corruption is detected"
1671	select DEBUG_LIST
1672	help
1673	  Select this option if the kernel should BUG when it encounters
1674	  data corruption in kernel memory structures when they get checked
1675	  for validity.
1676
1677	  If unsure, say N.
1678
1679config DEBUG_MAPLE_TREE
1680	bool "Debug maple trees"
1681	depends on DEBUG_KERNEL
1682	help
1683	  Enable maple tree debugging information and extra validations.
1684
1685	  If unsure, say N.
1686
1687endmenu
1688
1689config DEBUG_CREDENTIALS
1690	bool "Debug credential management"
1691	depends on DEBUG_KERNEL
1692	help
1693	  Enable this to turn on some debug checking for credential
1694	  management.  The additional code keeps track of the number of
1695	  pointers from task_structs to any given cred struct, and checks to
1696	  see that this number never exceeds the usage count of the cred
1697	  struct.
1698
1699	  Furthermore, if SELinux is enabled, this also checks that the
1700	  security pointer in the cred struct is never seen to be invalid.
1701
1702	  If unsure, say N.
1703
1704source "kernel/rcu/Kconfig.debug"
1705
1706config DEBUG_WQ_FORCE_RR_CPU
1707	bool "Force round-robin CPU selection for unbound work items"
1708	depends on DEBUG_KERNEL
1709	default n
1710	help
1711	  Workqueue used to implicitly guarantee that work items queued
1712	  without explicit CPU specified are put on the local CPU.  This
1713	  guarantee is no longer true and while local CPU is still
1714	  preferred work items may be put on foreign CPUs.  Kernel
1715	  parameter "workqueue.debug_force_rr_cpu" is added to force
1716	  round-robin CPU selection to flush out usages which depend on the
1717	  now broken guarantee.  This config option enables the debug
1718	  feature by default.  When enabled, memory and cache locality will
1719	  be impacted.
1720
1721config CPU_HOTPLUG_STATE_CONTROL
1722	bool "Enable CPU hotplug state control"
1723	depends on DEBUG_KERNEL
1724	depends on HOTPLUG_CPU
1725	default n
1726	help
1727	  Allows to write steps between "offline" and "online" to the CPUs
1728	  sysfs target file so states can be stepped granular. This is a debug
1729	  option for now as the hotplug machinery cannot be stopped and
1730	  restarted at arbitrary points yet.
1731
1732	  Say N if your are unsure.
1733
1734config LATENCYTOP
1735	bool "Latency measuring infrastructure"
1736	depends on DEBUG_KERNEL
1737	depends on STACKTRACE_SUPPORT
1738	depends on PROC_FS
1739	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1740	select KALLSYMS
1741	select KALLSYMS_ALL
1742	select STACKTRACE
1743	select SCHEDSTATS
1744	help
1745	  Enable this option if you want to use the LatencyTOP tool
1746	  to find out which userspace is blocking on what kernel operations.
1747
1748config DEBUG_CGROUP_REF
1749	bool "Disable inlining of cgroup css reference count functions"
1750	depends on DEBUG_KERNEL
1751	depends on CGROUPS
1752	depends on KPROBES
1753	default n
1754	help
1755	  Force cgroup css reference count functions to not be inlined so
1756	  that they can be kprobed for debugging.
1757
1758source "kernel/trace/Kconfig"
1759
1760config PROVIDE_OHCI1394_DMA_INIT
1761	bool "Remote debugging over FireWire early on boot"
1762	depends on PCI && X86
1763	help
1764	  If you want to debug problems which hang or crash the kernel early
1765	  on boot and the crashing machine has a FireWire port, you can use
1766	  this feature to remotely access the memory of the crashed machine
1767	  over FireWire. This employs remote DMA as part of the OHCI1394
1768	  specification which is now the standard for FireWire controllers.
1769
1770	  With remote DMA, you can monitor the printk buffer remotely using
1771	  firescope and access all memory below 4GB using fireproxy from gdb.
1772	  Even controlling a kernel debugger is possible using remote DMA.
1773
1774	  Usage:
1775
1776	  If ohci1394_dma=early is used as boot parameter, it will initialize
1777	  all OHCI1394 controllers which are found in the PCI config space.
1778
1779	  As all changes to the FireWire bus such as enabling and disabling
1780	  devices cause a bus reset and thereby disable remote DMA for all
1781	  devices, be sure to have the cable plugged and FireWire enabled on
1782	  the debugging host before booting the debug target for debugging.
1783
1784	  This code (~1k) is freed after boot. By then, the firewire stack
1785	  in charge of the OHCI-1394 controllers should be used instead.
1786
1787	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1788
1789source "samples/Kconfig"
1790
1791config ARCH_HAS_DEVMEM_IS_ALLOWED
1792	bool
1793
1794config STRICT_DEVMEM
1795	bool "Filter access to /dev/mem"
1796	depends on MMU && DEVMEM
1797	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1798	default y if PPC || X86 || ARM64
1799	help
1800	  If this option is disabled, you allow userspace (root) access to all
1801	  of memory, including kernel and userspace memory. Accidental
1802	  access to this is obviously disastrous, but specific access can
1803	  be used by people debugging the kernel. Note that with PAT support
1804	  enabled, even in this case there are restrictions on /dev/mem
1805	  use due to the cache aliasing requirements.
1806
1807	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1808	  file only allows userspace access to PCI space and the BIOS code and
1809	  data regions.  This is sufficient for dosemu and X and all common
1810	  users of /dev/mem.
1811
1812	  If in doubt, say Y.
1813
1814config IO_STRICT_DEVMEM
1815	bool "Filter I/O access to /dev/mem"
1816	depends on STRICT_DEVMEM
1817	help
1818	  If this option is disabled, you allow userspace (root) access to all
1819	  io-memory regardless of whether a driver is actively using that
1820	  range.  Accidental access to this is obviously disastrous, but
1821	  specific access can be used by people debugging kernel drivers.
1822
1823	  If this option is switched on, the /dev/mem file only allows
1824	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1825	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1826	  if the driver using a given range cannot be disabled.
1827
1828	  If in doubt, say Y.
1829
1830menu "$(SRCARCH) Debugging"
1831
1832source "arch/$(SRCARCH)/Kconfig.debug"
1833
1834endmenu
1835
1836menu "Kernel Testing and Coverage"
1837
1838source "lib/kunit/Kconfig"
1839
1840config NOTIFIER_ERROR_INJECTION
1841	tristate "Notifier error injection"
1842	depends on DEBUG_KERNEL
1843	select DEBUG_FS
1844	help
1845	  This option provides the ability to inject artificial errors to
1846	  specified notifier chain callbacks. It is useful to test the error
1847	  handling of notifier call chain failures.
1848
1849	  Say N if unsure.
1850
1851config PM_NOTIFIER_ERROR_INJECT
1852	tristate "PM notifier error injection module"
1853	depends on PM && NOTIFIER_ERROR_INJECTION
1854	default m if PM_DEBUG
1855	help
1856	  This option provides the ability to inject artificial errors to
1857	  PM notifier chain callbacks.  It is controlled through debugfs
1858	  interface /sys/kernel/debug/notifier-error-inject/pm
1859
1860	  If the notifier call chain should be failed with some events
1861	  notified, write the error code to "actions/<notifier event>/error".
1862
1863	  Example: Inject PM suspend error (-12 = -ENOMEM)
1864
1865	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1866	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1867	  # echo mem > /sys/power/state
1868	  bash: echo: write error: Cannot allocate memory
1869
1870	  To compile this code as a module, choose M here: the module will
1871	  be called pm-notifier-error-inject.
1872
1873	  If unsure, say N.
1874
1875config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1876	tristate "OF reconfig notifier error injection module"
1877	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1878	help
1879	  This option provides the ability to inject artificial errors to
1880	  OF reconfig notifier chain callbacks.  It is controlled
1881	  through debugfs interface under
1882	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1883
1884	  If the notifier call chain should be failed with some events
1885	  notified, write the error code to "actions/<notifier event>/error".
1886
1887	  To compile this code as a module, choose M here: the module will
1888	  be called of-reconfig-notifier-error-inject.
1889
1890	  If unsure, say N.
1891
1892config NETDEV_NOTIFIER_ERROR_INJECT
1893	tristate "Netdev notifier error injection module"
1894	depends on NET && NOTIFIER_ERROR_INJECTION
1895	help
1896	  This option provides the ability to inject artificial errors to
1897	  netdevice notifier chain callbacks.  It is controlled through debugfs
1898	  interface /sys/kernel/debug/notifier-error-inject/netdev
1899
1900	  If the notifier call chain should be failed with some events
1901	  notified, write the error code to "actions/<notifier event>/error".
1902
1903	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
1904
1905	  # cd /sys/kernel/debug/notifier-error-inject/netdev
1906	  # echo -22 > actions/NETDEV_CHANGEMTU/error
1907	  # ip link set eth0 mtu 1024
1908	  RTNETLINK answers: Invalid argument
1909
1910	  To compile this code as a module, choose M here: the module will
1911	  be called netdev-notifier-error-inject.
1912
1913	  If unsure, say N.
1914
1915config FUNCTION_ERROR_INJECTION
1916	bool "Fault-injections of functions"
1917	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1918	help
1919	  Add fault injections into various functions that are annotated with
1920	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1921	  value of these functions. This is useful to test error paths of code.
1922
1923	  If unsure, say N
1924
1925config FAULT_INJECTION
1926	bool "Fault-injection framework"
1927	depends on DEBUG_KERNEL
1928	help
1929	  Provide fault-injection framework.
1930	  For more details, see Documentation/fault-injection/.
1931
1932config FAILSLAB
1933	bool "Fault-injection capability for kmalloc"
1934	depends on FAULT_INJECTION
1935	depends on SLAB || SLUB
1936	help
1937	  Provide fault-injection capability for kmalloc.
1938
1939config FAIL_PAGE_ALLOC
1940	bool "Fault-injection capability for alloc_pages()"
1941	depends on FAULT_INJECTION
1942	help
1943	  Provide fault-injection capability for alloc_pages().
1944
1945config FAULT_INJECTION_USERCOPY
1946	bool "Fault injection capability for usercopy functions"
1947	depends on FAULT_INJECTION
1948	help
1949	  Provides fault-injection capability to inject failures
1950	  in usercopy functions (copy_from_user(), get_user(), ...).
1951
1952config FAIL_MAKE_REQUEST
1953	bool "Fault-injection capability for disk IO"
1954	depends on FAULT_INJECTION && BLOCK
1955	help
1956	  Provide fault-injection capability for disk IO.
1957
1958config FAIL_IO_TIMEOUT
1959	bool "Fault-injection capability for faking disk interrupts"
1960	depends on FAULT_INJECTION && BLOCK
1961	help
1962	  Provide fault-injection capability on end IO handling. This
1963	  will make the block layer "forget" an interrupt as configured,
1964	  thus exercising the error handling.
1965
1966	  Only works with drivers that use the generic timeout handling,
1967	  for others it won't do anything.
1968
1969config FAIL_FUTEX
1970	bool "Fault-injection capability for futexes"
1971	select DEBUG_FS
1972	depends on FAULT_INJECTION && FUTEX
1973	help
1974	  Provide fault-injection capability for futexes.
1975
1976config FAULT_INJECTION_DEBUG_FS
1977	bool "Debugfs entries for fault-injection capabilities"
1978	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1979	help
1980	  Enable configuration of fault-injection capabilities via debugfs.
1981
1982config FAIL_FUNCTION
1983	bool "Fault-injection capability for functions"
1984	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1985	help
1986	  Provide function-based fault-injection capability.
1987	  This will allow you to override a specific function with a return
1988	  with given return value. As a result, function caller will see
1989	  an error value and have to handle it. This is useful to test the
1990	  error handling in various subsystems.
1991
1992config FAIL_MMC_REQUEST
1993	bool "Fault-injection capability for MMC IO"
1994	depends on FAULT_INJECTION_DEBUG_FS && MMC
1995	help
1996	  Provide fault-injection capability for MMC IO.
1997	  This will make the mmc core return data errors. This is
1998	  useful to test the error handling in the mmc block device
1999	  and to test how the mmc host driver handles retries from
2000	  the block device.
2001
2002config FAIL_SUNRPC
2003	bool "Fault-injection capability for SunRPC"
2004	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2005	help
2006	  Provide fault-injection capability for SunRPC and
2007	  its consumers.
2008
2009config FAULT_INJECTION_STACKTRACE_FILTER
2010	bool "stacktrace filter for fault-injection capabilities"
2011	depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2012	select STACKTRACE
2013	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2014	help
2015	  Provide stacktrace filter for fault-injection capabilities
2016
2017config ARCH_HAS_KCOV
2018	bool
2019	help
2020	  An architecture should select this when it can successfully
2021	  build and run with CONFIG_KCOV. This typically requires
2022	  disabling instrumentation for some early boot code.
2023
2024config CC_HAS_SANCOV_TRACE_PC
2025	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2026
2027
2028config KCOV
2029	bool "Code coverage for fuzzing"
2030	depends on ARCH_HAS_KCOV
2031	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2032	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2033		   GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2034	select DEBUG_FS
2035	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2036	select OBJTOOL if HAVE_NOINSTR_HACK
2037	help
2038	  KCOV exposes kernel code coverage information in a form suitable
2039	  for coverage-guided fuzzing (randomized testing).
2040
2041	  If RANDOMIZE_BASE is enabled, PC values will not be stable across
2042	  different machines and across reboots. If you need stable PC values,
2043	  disable RANDOMIZE_BASE.
2044
2045	  For more details, see Documentation/dev-tools/kcov.rst.
2046
2047config KCOV_ENABLE_COMPARISONS
2048	bool "Enable comparison operands collection by KCOV"
2049	depends on KCOV
2050	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2051	help
2052	  KCOV also exposes operands of every comparison in the instrumented
2053	  code along with operand sizes and PCs of the comparison instructions.
2054	  These operands can be used by fuzzing engines to improve the quality
2055	  of fuzzing coverage.
2056
2057config KCOV_INSTRUMENT_ALL
2058	bool "Instrument all code by default"
2059	depends on KCOV
2060	default y
2061	help
2062	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2063	  then you will want to instrument the whole kernel and you should
2064	  say y here. If you are doing more targeted fuzzing (like e.g.
2065	  filesystem fuzzing with AFL) then you will want to enable coverage
2066	  for more specific subsets of files, and should say n here.
2067
2068config KCOV_IRQ_AREA_SIZE
2069	hex "Size of interrupt coverage collection area in words"
2070	depends on KCOV
2071	default 0x40000
2072	help
2073	  KCOV uses preallocated per-cpu areas to collect coverage from
2074	  soft interrupts. This specifies the size of those areas in the
2075	  number of unsigned long words.
2076
2077menuconfig RUNTIME_TESTING_MENU
2078	bool "Runtime Testing"
2079	def_bool y
2080
2081if RUNTIME_TESTING_MENU
2082
2083config LKDTM
2084	tristate "Linux Kernel Dump Test Tool Module"
2085	depends on DEBUG_FS
2086	help
2087	This module enables testing of the different dumping mechanisms by
2088	inducing system failures at predefined crash points.
2089	If you don't need it: say N
2090	Choose M here to compile this code as a module. The module will be
2091	called lkdtm.
2092
2093	Documentation on how to use the module can be found in
2094	Documentation/fault-injection/provoke-crashes.rst
2095
2096config CPUMASK_KUNIT_TEST
2097	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2098	depends on KUNIT
2099	default KUNIT_ALL_TESTS
2100	help
2101	  Enable to turn on cpumask tests, running at boot or module load time.
2102
2103	  For more information on KUnit and unit tests in general, please refer
2104	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2105
2106	  If unsure, say N.
2107
2108config TEST_LIST_SORT
2109	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2110	depends on KUNIT
2111	default KUNIT_ALL_TESTS
2112	help
2113	  Enable this to turn on 'list_sort()' function test. This test is
2114	  executed only once during system boot (so affects only boot time),
2115	  or at module load time.
2116
2117	  If unsure, say N.
2118
2119config TEST_MIN_HEAP
2120	tristate "Min heap test"
2121	depends on DEBUG_KERNEL || m
2122	help
2123	  Enable this to turn on min heap function tests. This test is
2124	  executed only once during system boot (so affects only boot time),
2125	  or at module load time.
2126
2127	  If unsure, say N.
2128
2129config TEST_SORT
2130	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2131	depends on KUNIT
2132	default KUNIT_ALL_TESTS
2133	help
2134	  This option enables the self-test function of 'sort()' at boot,
2135	  or at module load time.
2136
2137	  If unsure, say N.
2138
2139config TEST_DIV64
2140	tristate "64bit/32bit division and modulo test"
2141	depends on DEBUG_KERNEL || m
2142	help
2143	  Enable this to turn on 'do_div()' function test. This test is
2144	  executed only once during system boot (so affects only boot time),
2145	  or at module load time.
2146
2147	  If unsure, say N.
2148
2149config KPROBES_SANITY_TEST
2150	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2151	depends on DEBUG_KERNEL
2152	depends on KPROBES
2153	depends on KUNIT
2154	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2155	default KUNIT_ALL_TESTS
2156	help
2157	  This option provides for testing basic kprobes functionality on
2158	  boot. Samples of kprobe and kretprobe are inserted and
2159	  verified for functionality.
2160
2161	  Say N if you are unsure.
2162
2163config FPROBE_SANITY_TEST
2164	bool "Self test for fprobe"
2165	depends on DEBUG_KERNEL
2166	depends on FPROBE
2167	depends on KUNIT=y
2168	help
2169	  This option will enable testing the fprobe when the system boot.
2170	  A series of tests are made to verify that the fprobe is functioning
2171	  properly.
2172
2173	  Say N if you are unsure.
2174
2175config BACKTRACE_SELF_TEST
2176	tristate "Self test for the backtrace code"
2177	depends on DEBUG_KERNEL
2178	help
2179	  This option provides a kernel module that can be used to test
2180	  the kernel stack backtrace code. This option is not useful
2181	  for distributions or general kernels, but only for kernel
2182	  developers working on architecture code.
2183
2184	  Note that if you want to also test saved backtraces, you will
2185	  have to enable STACKTRACE as well.
2186
2187	  Say N if you are unsure.
2188
2189config TEST_REF_TRACKER
2190	tristate "Self test for reference tracker"
2191	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2192	select REF_TRACKER
2193	help
2194	  This option provides a kernel module performing tests
2195	  using reference tracker infrastructure.
2196
2197	  Say N if you are unsure.
2198
2199config RBTREE_TEST
2200	tristate "Red-Black tree test"
2201	depends on DEBUG_KERNEL
2202	help
2203	  A benchmark measuring the performance of the rbtree library.
2204	  Also includes rbtree invariant checks.
2205
2206config REED_SOLOMON_TEST
2207	tristate "Reed-Solomon library test"
2208	depends on DEBUG_KERNEL || m
2209	select REED_SOLOMON
2210	select REED_SOLOMON_ENC16
2211	select REED_SOLOMON_DEC16
2212	help
2213	  This option enables the self-test function of rslib at boot,
2214	  or at module load time.
2215
2216	  If unsure, say N.
2217
2218config INTERVAL_TREE_TEST
2219	tristate "Interval tree test"
2220	depends on DEBUG_KERNEL
2221	select INTERVAL_TREE
2222	help
2223	  A benchmark measuring the performance of the interval tree library
2224
2225config PERCPU_TEST
2226	tristate "Per cpu operations test"
2227	depends on m && DEBUG_KERNEL
2228	help
2229	  Enable this option to build test module which validates per-cpu
2230	  operations.
2231
2232	  If unsure, say N.
2233
2234config ATOMIC64_SELFTEST
2235	tristate "Perform an atomic64_t self-test"
2236	help
2237	  Enable this option to test the atomic64_t functions at boot or
2238	  at module load time.
2239
2240	  If unsure, say N.
2241
2242config ASYNC_RAID6_TEST
2243	tristate "Self test for hardware accelerated raid6 recovery"
2244	depends on ASYNC_RAID6_RECOV
2245	select ASYNC_MEMCPY
2246	help
2247	  This is a one-shot self test that permutes through the
2248	  recovery of all the possible two disk failure scenarios for a
2249	  N-disk array.  Recovery is performed with the asynchronous
2250	  raid6 recovery routines, and will optionally use an offload
2251	  engine if one is available.
2252
2253	  If unsure, say N.
2254
2255config TEST_HEXDUMP
2256	tristate "Test functions located in the hexdump module at runtime"
2257
2258config STRING_SELFTEST
2259	tristate "Test string functions at runtime"
2260
2261config TEST_STRING_HELPERS
2262	tristate "Test functions located in the string_helpers module at runtime"
2263
2264config TEST_KSTRTOX
2265	tristate "Test kstrto*() family of functions at runtime"
2266
2267config TEST_PRINTF
2268	tristate "Test printf() family of functions at runtime"
2269
2270config TEST_SCANF
2271	tristate "Test scanf() family of functions at runtime"
2272
2273config TEST_BITMAP
2274	tristate "Test bitmap_*() family of functions at runtime"
2275	help
2276	  Enable this option to test the bitmap functions at boot.
2277
2278	  If unsure, say N.
2279
2280config TEST_UUID
2281	tristate "Test functions located in the uuid module at runtime"
2282
2283config TEST_XARRAY
2284	tristate "Test the XArray code at runtime"
2285
2286config TEST_MAPLE_TREE
2287	depends on DEBUG_KERNEL
2288	select DEBUG_MAPLE_TREE
2289	tristate "Test the Maple Tree code at runtime"
2290
2291config TEST_RHASHTABLE
2292	tristate "Perform selftest on resizable hash table"
2293	help
2294	  Enable this option to test the rhashtable functions at boot.
2295
2296	  If unsure, say N.
2297
2298config TEST_IDA
2299	tristate "Perform selftest on IDA functions"
2300
2301config TEST_PARMAN
2302	tristate "Perform selftest on priority array manager"
2303	depends on PARMAN
2304	help
2305	  Enable this option to test priority array manager on boot
2306	  (or module load).
2307
2308	  If unsure, say N.
2309
2310config TEST_IRQ_TIMINGS
2311	bool "IRQ timings selftest"
2312	depends on IRQ_TIMINGS
2313	help
2314	  Enable this option to test the irq timings code on boot.
2315
2316	  If unsure, say N.
2317
2318config TEST_LKM
2319	tristate "Test module loading with 'hello world' module"
2320	depends on m
2321	help
2322	  This builds the "test_module" module that emits "Hello, world"
2323	  on printk when loaded. It is designed to be used for basic
2324	  evaluation of the module loading subsystem (for example when
2325	  validating module verification). It lacks any extra dependencies,
2326	  and will not normally be loaded by the system unless explicitly
2327	  requested by name.
2328
2329	  If unsure, say N.
2330
2331config TEST_BITOPS
2332	tristate "Test module for compilation of bitops operations"
2333	depends on m
2334	help
2335	  This builds the "test_bitops" module that is much like the
2336	  TEST_LKM module except that it does a basic exercise of the
2337	  set/clear_bit macros and get_count_order/long to make sure there are
2338	  no compiler warnings from C=1 sparse checker or -Wextra
2339	  compilations. It has no dependencies and doesn't run or load unless
2340	  explicitly requested by name.  for example: modprobe test_bitops.
2341
2342	  If unsure, say N.
2343
2344config TEST_VMALLOC
2345	tristate "Test module for stress/performance analysis of vmalloc allocator"
2346	default n
2347       depends on MMU
2348	depends on m
2349	help
2350	  This builds the "test_vmalloc" module that should be used for
2351	  stress and performance analysis. So, any new change for vmalloc
2352	  subsystem can be evaluated from performance and stability point
2353	  of view.
2354
2355	  If unsure, say N.
2356
2357config TEST_USER_COPY
2358	tristate "Test user/kernel boundary protections"
2359	depends on m
2360	help
2361	  This builds the "test_user_copy" module that runs sanity checks
2362	  on the copy_to/from_user infrastructure, making sure basic
2363	  user/kernel boundary testing is working. If it fails to load,
2364	  a regression has been detected in the user/kernel memory boundary
2365	  protections.
2366
2367	  If unsure, say N.
2368
2369config TEST_BPF
2370	tristate "Test BPF filter functionality"
2371	depends on m && NET
2372	help
2373	  This builds the "test_bpf" module that runs various test vectors
2374	  against the BPF interpreter or BPF JIT compiler depending on the
2375	  current setting. This is in particular useful for BPF JIT compiler
2376	  development, but also to run regression tests against changes in
2377	  the interpreter code. It also enables test stubs for eBPF maps and
2378	  verifier used by user space verifier testsuite.
2379
2380	  If unsure, say N.
2381
2382config TEST_BLACKHOLE_DEV
2383	tristate "Test blackhole netdev functionality"
2384	depends on m && NET
2385	help
2386	  This builds the "test_blackhole_dev" module that validates the
2387	  data path through this blackhole netdev.
2388
2389	  If unsure, say N.
2390
2391config FIND_BIT_BENCHMARK
2392	tristate "Test find_bit functions"
2393	help
2394	  This builds the "test_find_bit" module that measure find_*_bit()
2395	  functions performance.
2396
2397	  If unsure, say N.
2398
2399config TEST_FIRMWARE
2400	tristate "Test firmware loading via userspace interface"
2401	depends on FW_LOADER
2402	help
2403	  This builds the "test_firmware" module that creates a userspace
2404	  interface for testing firmware loading. This can be used to
2405	  control the triggering of firmware loading without needing an
2406	  actual firmware-using device. The contents can be rechecked by
2407	  userspace.
2408
2409	  If unsure, say N.
2410
2411config TEST_SYSCTL
2412	tristate "sysctl test driver"
2413	depends on PROC_SYSCTL
2414	help
2415	  This builds the "test_sysctl" module. This driver enables to test the
2416	  proc sysctl interfaces available to drivers safely without affecting
2417	  production knobs which might alter system functionality.
2418
2419	  If unsure, say N.
2420
2421config BITFIELD_KUNIT
2422	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2423	depends on KUNIT
2424	default KUNIT_ALL_TESTS
2425	help
2426	  Enable this option to test the bitfield functions at boot.
2427
2428	  KUnit tests run during boot and output the results to the debug log
2429	  in TAP format (http://testanything.org/). Only useful for kernel devs
2430	  running the KUnit test harness, and not intended for inclusion into a
2431	  production build.
2432
2433	  For more information on KUnit and unit tests in general please refer
2434	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2435
2436	  If unsure, say N.
2437
2438config HASH_KUNIT_TEST
2439	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2440	depends on KUNIT
2441	default KUNIT_ALL_TESTS
2442	help
2443	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2444	  integer (<linux/hash.h>) hash functions on boot.
2445
2446	  KUnit tests run during boot and output the results to the debug log
2447	  in TAP format (https://testanything.org/). Only useful for kernel devs
2448	  running the KUnit test harness, and not intended for inclusion into a
2449	  production build.
2450
2451	  For more information on KUnit and unit tests in general please refer
2452	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2453
2454	  This is intended to help people writing architecture-specific
2455	  optimized versions. If unsure, say N.
2456
2457config RESOURCE_KUNIT_TEST
2458	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2459	depends on KUNIT
2460	default KUNIT_ALL_TESTS
2461	help
2462	  This builds the resource API unit test.
2463	  Tests the logic of API provided by resource.c and ioport.h.
2464	  For more information on KUnit and unit tests in general please refer
2465	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2466
2467	  If unsure, say N.
2468
2469config SYSCTL_KUNIT_TEST
2470	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2471	depends on KUNIT
2472	default KUNIT_ALL_TESTS
2473	help
2474	  This builds the proc sysctl unit test, which runs on boot.
2475	  Tests the API contract and implementation correctness of sysctl.
2476	  For more information on KUnit and unit tests in general please refer
2477	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2478
2479	  If unsure, say N.
2480
2481config LIST_KUNIT_TEST
2482	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2483	depends on KUNIT
2484	default KUNIT_ALL_TESTS
2485	help
2486	  This builds the linked list KUnit test suite.
2487	  It tests that the API and basic functionality of the list_head type
2488	  and associated macros.
2489
2490	  KUnit tests run during boot and output the results to the debug log
2491	  in TAP format (https://testanything.org/). Only useful for kernel devs
2492	  running the KUnit test harness, and not intended for inclusion into a
2493	  production build.
2494
2495	  For more information on KUnit and unit tests in general please refer
2496	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2497
2498	  If unsure, say N.
2499
2500config LINEAR_RANGES_TEST
2501	tristate "KUnit test for linear_ranges"
2502	depends on KUNIT
2503	select LINEAR_RANGES
2504	help
2505	  This builds the linear_ranges unit test, which runs on boot.
2506	  Tests the linear_ranges logic correctness.
2507	  For more information on KUnit and unit tests in general please refer
2508	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2509
2510	  If unsure, say N.
2511
2512config CMDLINE_KUNIT_TEST
2513	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2514	depends on KUNIT
2515	default KUNIT_ALL_TESTS
2516	help
2517	  This builds the cmdline API unit test.
2518	  Tests the logic of API provided by cmdline.c.
2519	  For more information on KUnit and unit tests in general please refer
2520	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2521
2522	  If unsure, say N.
2523
2524config BITS_TEST
2525	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2526	depends on KUNIT
2527	default KUNIT_ALL_TESTS
2528	help
2529	  This builds the bits unit test.
2530	  Tests the logic of macros defined in bits.h.
2531	  For more information on KUnit and unit tests in general please refer
2532	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2533
2534	  If unsure, say N.
2535
2536config SLUB_KUNIT_TEST
2537	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2538	depends on SLUB_DEBUG && KUNIT
2539	default KUNIT_ALL_TESTS
2540	help
2541	  This builds SLUB allocator unit test.
2542	  Tests SLUB cache debugging functionality.
2543	  For more information on KUnit and unit tests in general please refer
2544	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2545
2546	  If unsure, say N.
2547
2548config RATIONAL_KUNIT_TEST
2549	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2550	depends on KUNIT && RATIONAL
2551	default KUNIT_ALL_TESTS
2552	help
2553	  This builds the rational math unit test.
2554	  For more information on KUnit and unit tests in general please refer
2555	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2556
2557	  If unsure, say N.
2558
2559config MEMCPY_KUNIT_TEST
2560	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2561	depends on KUNIT
2562	default KUNIT_ALL_TESTS
2563	help
2564	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2565	  For more information on KUnit and unit tests in general please refer
2566	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2567
2568	  If unsure, say N.
2569
2570config MEMCPY_SLOW_KUNIT_TEST
2571	bool "Include exhaustive memcpy tests"
2572	depends on MEMCPY_KUNIT_TEST
2573	default y
2574	help
2575	  Some memcpy tests are quite exhaustive in checking for overlaps
2576	  and bit ranges. These can be very slow, so they are split out
2577	  as a separate config, in case they need to be disabled.
2578
2579config IS_SIGNED_TYPE_KUNIT_TEST
2580	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2581	depends on KUNIT
2582	default KUNIT_ALL_TESTS
2583	help
2584	  Builds unit tests for the is_signed_type() macro.
2585
2586	  For more information on KUnit and unit tests in general please refer
2587	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2588
2589	  If unsure, say N.
2590
2591config OVERFLOW_KUNIT_TEST
2592	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2593	depends on KUNIT
2594	default KUNIT_ALL_TESTS
2595	help
2596	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2597	  related functions.
2598
2599	  For more information on KUnit and unit tests in general please refer
2600	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2601
2602	  If unsure, say N.
2603
2604config STACKINIT_KUNIT_TEST
2605	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2606	depends on KUNIT
2607	default KUNIT_ALL_TESTS
2608	help
2609	  Test if the kernel is zero-initializing stack variables and
2610	  padding. Coverage is controlled by compiler flags,
2611	  CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2612	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2613	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2614
2615config FORTIFY_KUNIT_TEST
2616	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2617	depends on KUNIT && FORTIFY_SOURCE
2618	default KUNIT_ALL_TESTS
2619	help
2620	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2621	  by the str*() and mem*() family of functions. For testing runtime
2622	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2623
2624config HW_BREAKPOINT_KUNIT_TEST
2625	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2626	depends on HAVE_HW_BREAKPOINT
2627	depends on KUNIT=y
2628	default KUNIT_ALL_TESTS
2629	help
2630	  Tests for hw_breakpoint constraints accounting.
2631
2632	  If unsure, say N.
2633
2634config STRSCPY_KUNIT_TEST
2635	tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2636	depends on KUNIT
2637	default KUNIT_ALL_TESTS
2638
2639config SIPHASH_KUNIT_TEST
2640	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2641	depends on KUNIT
2642	default KUNIT_ALL_TESTS
2643	help
2644	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2645	  functions on boot (or module load).
2646
2647	  This is intended to help people writing architecture-specific
2648	  optimized versions.  If unsure, say N.
2649
2650config TEST_UDELAY
2651	tristate "udelay test driver"
2652	help
2653	  This builds the "udelay_test" module that helps to make sure
2654	  that udelay() is working properly.
2655
2656	  If unsure, say N.
2657
2658config TEST_STATIC_KEYS
2659	tristate "Test static keys"
2660	depends on m
2661	help
2662	  Test the static key interfaces.
2663
2664	  If unsure, say N.
2665
2666config TEST_DYNAMIC_DEBUG
2667	tristate "Test DYNAMIC_DEBUG"
2668	depends on DYNAMIC_DEBUG
2669	help
2670	  This module registers a tracer callback to count enabled
2671	  pr_debugs in a 'do_debugging' function, then alters their
2672	  enablements, calls the function, and compares counts.
2673
2674	  If unsure, say N.
2675
2676config TEST_KMOD
2677	tristate "kmod stress tester"
2678	depends on m
2679	depends on NETDEVICES && NET_CORE && INET # for TUN
2680	depends on BLOCK
2681	depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2682	select TEST_LKM
2683	select XFS_FS
2684	select TUN
2685	select BTRFS_FS
2686	help
2687	  Test the kernel's module loading mechanism: kmod. kmod implements
2688	  support to load modules using the Linux kernel's usermode helper.
2689	  This test provides a series of tests against kmod.
2690
2691	  Although technically you can either build test_kmod as a module or
2692	  into the kernel we disallow building it into the kernel since
2693	  it stress tests request_module() and this will very likely cause
2694	  some issues by taking over precious threads available from other
2695	  module load requests, ultimately this could be fatal.
2696
2697	  To run tests run:
2698
2699	  tools/testing/selftests/kmod/kmod.sh --help
2700
2701	  If unsure, say N.
2702
2703config TEST_DEBUG_VIRTUAL
2704	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2705	depends on DEBUG_VIRTUAL
2706	help
2707	  Test the kernel's ability to detect incorrect calls to
2708	  virt_to_phys() done against the non-linear part of the
2709	  kernel's virtual address map.
2710
2711	  If unsure, say N.
2712
2713config TEST_MEMCAT_P
2714	tristate "Test memcat_p() helper function"
2715	help
2716	  Test the memcat_p() helper for correctly merging two
2717	  pointer arrays together.
2718
2719	  If unsure, say N.
2720
2721config TEST_LIVEPATCH
2722	tristate "Test livepatching"
2723	default n
2724	depends on DYNAMIC_DEBUG
2725	depends on LIVEPATCH
2726	depends on m
2727	help
2728	  Test kernel livepatching features for correctness.  The tests will
2729	  load test modules that will be livepatched in various scenarios.
2730
2731	  To run all the livepatching tests:
2732
2733	  make -C tools/testing/selftests TARGETS=livepatch run_tests
2734
2735	  Alternatively, individual tests may be invoked:
2736
2737	  tools/testing/selftests/livepatch/test-callbacks.sh
2738	  tools/testing/selftests/livepatch/test-livepatch.sh
2739	  tools/testing/selftests/livepatch/test-shadow-vars.sh
2740
2741	  If unsure, say N.
2742
2743config TEST_OBJAGG
2744	tristate "Perform selftest on object aggreration manager"
2745	default n
2746	depends on OBJAGG
2747	help
2748	  Enable this option to test object aggregation manager on boot
2749	  (or module load).
2750
2751config TEST_MEMINIT
2752	tristate "Test heap/page initialization"
2753	help
2754	  Test if the kernel is zero-initializing heap and page allocations.
2755	  This can be useful to test init_on_alloc and init_on_free features.
2756
2757	  If unsure, say N.
2758
2759config TEST_HMM
2760	tristate "Test HMM (Heterogeneous Memory Management)"
2761	depends on TRANSPARENT_HUGEPAGE
2762	depends on DEVICE_PRIVATE
2763	select HMM_MIRROR
2764	select MMU_NOTIFIER
2765	help
2766	  This is a pseudo device driver solely for testing HMM.
2767	  Say M here if you want to build the HMM test module.
2768	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2769
2770	  If unsure, say N.
2771
2772config TEST_FREE_PAGES
2773	tristate "Test freeing pages"
2774	help
2775	  Test that a memory leak does not occur due to a race between
2776	  freeing a block of pages and a speculative page reference.
2777	  Loading this module is safe if your kernel has the bug fixed.
2778	  If the bug is not fixed, it will leak gigabytes of memory and
2779	  probably OOM your system.
2780
2781config TEST_FPU
2782	tristate "Test floating point operations in kernel space"
2783	depends on X86 && !KCOV_INSTRUMENT_ALL
2784	help
2785	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2786	  which will trigger a sequence of floating point operations. This is used
2787	  for self-testing floating point control register setting in
2788	  kernel_fpu_begin().
2789
2790	  If unsure, say N.
2791
2792config TEST_CLOCKSOURCE_WATCHDOG
2793	tristate "Test clocksource watchdog in kernel space"
2794	depends on CLOCKSOURCE_WATCHDOG
2795	help
2796	  Enable this option to create a kernel module that will trigger
2797	  a test of the clocksource watchdog.  This module may be loaded
2798	  via modprobe or insmod in which case it will run upon being
2799	  loaded, or it may be built in, in which case it will run
2800	  shortly after boot.
2801
2802	  If unsure, say N.
2803
2804endif # RUNTIME_TESTING_MENU
2805
2806config ARCH_USE_MEMTEST
2807	bool
2808	help
2809	  An architecture should select this when it uses early_memtest()
2810	  during boot process.
2811
2812config MEMTEST
2813	bool "Memtest"
2814	depends on ARCH_USE_MEMTEST
2815	help
2816	  This option adds a kernel parameter 'memtest', which allows memtest
2817	  to be set and executed.
2818	        memtest=0, mean disabled; -- default
2819	        memtest=1, mean do 1 test pattern;
2820	        ...
2821	        memtest=17, mean do 17 test patterns.
2822	  If you are unsure how to answer this question, answer N.
2823
2824
2825
2826config HYPERV_TESTING
2827	bool "Microsoft Hyper-V driver testing"
2828	default n
2829	depends on HYPERV && DEBUG_FS
2830	help
2831	  Select this option to enable Hyper-V vmbus testing.
2832
2833endmenu # "Kernel Testing and Coverage"
2834
2835menu "Rust hacking"
2836
2837config RUST_DEBUG_ASSERTIONS
2838	bool "Debug assertions"
2839	depends on RUST
2840	help
2841	  Enables rustc's `-Cdebug-assertions` codegen option.
2842
2843	  This flag lets you turn `cfg(debug_assertions)` conditional
2844	  compilation on or off. This can be used to enable extra debugging
2845	  code in development but not in production. For example, it controls
2846	  the behavior of the standard library's `debug_assert!` macro.
2847
2848	  Note that this will apply to all Rust code, including `core`.
2849
2850	  If unsure, say N.
2851
2852config RUST_OVERFLOW_CHECKS
2853	bool "Overflow checks"
2854	default y
2855	depends on RUST
2856	help
2857	  Enables rustc's `-Coverflow-checks` codegen option.
2858
2859	  This flag allows you to control the behavior of runtime integer
2860	  overflow. When overflow-checks are enabled, a Rust panic will occur
2861	  on overflow.
2862
2863	  Note that this will apply to all Rust code, including `core`.
2864
2865	  If unsure, say Y.
2866
2867config RUST_BUILD_ASSERT_ALLOW
2868	bool "Allow unoptimized build-time assertions"
2869	depends on RUST
2870	help
2871	  Controls how are `build_error!` and `build_assert!` handled during build.
2872
2873	  If calls to them exist in the binary, it may indicate a violated invariant
2874	  or that the optimizer failed to verify the invariant during compilation.
2875
2876	  This should not happen, thus by default the build is aborted. However,
2877	  as an escape hatch, you can choose Y here to ignore them during build
2878	  and let the check be carried at runtime (with `panic!` being called if
2879	  the check fails).
2880
2881	  If unsure, say N.
2882
2883endmenu # "Rust"
2884
2885source "Documentation/Kconfig"
2886
2887endmenu # Kernel hacking
2888