xref: /linux-6.15/lib/Kconfig.debug (revision e89bd9e7)
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	help
758	  Say Y here if you want to enable the memory leak
759	  detector. The memory allocation/freeing is traced in a way
760	  similar to the Boehm's conservative garbage collector, the
761	  difference being that the orphan objects are not freed but
762	  only shown in /sys/kernel/debug/kmemleak. Enabling this
763	  feature will introduce an overhead to memory
764	  allocations. See Documentation/dev-tools/kmemleak.rst for more
765	  details.
766
767	  Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
768	  of finding leaks due to the slab objects poisoning.
769
770	  In order to access the kmemleak file, debugfs needs to be
771	  mounted (usually at /sys/kernel/debug).
772
773config DEBUG_KMEMLEAK_MEM_POOL_SIZE
774	int "Kmemleak memory pool size"
775	depends on DEBUG_KMEMLEAK
776	range 200 1000000
777	default 16000
778	help
779	  Kmemleak must track all the memory allocations to avoid
780	  reporting false positives. Since memory may be allocated or
781	  freed before kmemleak is fully initialised, use a static pool
782	  of metadata objects to track such callbacks. After kmemleak is
783	  fully initialised, this memory pool acts as an emergency one
784	  if slab allocations fail.
785
786config DEBUG_KMEMLEAK_TEST
787	tristate "Simple test for the kernel memory leak detector"
788	depends on DEBUG_KMEMLEAK && m
789	help
790	  This option enables a module that explicitly leaks memory.
791
792	  If unsure, say N.
793
794config DEBUG_KMEMLEAK_DEFAULT_OFF
795	bool "Default kmemleak to off"
796	depends on DEBUG_KMEMLEAK
797	help
798	  Say Y here to disable kmemleak by default. It can then be enabled
799	  on the command line via kmemleak=on.
800
801config DEBUG_KMEMLEAK_AUTO_SCAN
802	bool "Enable kmemleak auto scan thread on boot up"
803	default y
804	depends on DEBUG_KMEMLEAK
805	help
806	  Depending on the cpu, kmemleak scan may be cpu intensive and can
807	  stall user tasks at times. This option enables/disables automatic
808	  kmemleak scan at boot up.
809
810	  Say N here to disable kmemleak auto scan thread to stop automatic
811	  scanning. Disabling this option disables automatic reporting of
812	  memory leaks.
813
814	  If unsure, say Y.
815
816config DEBUG_STACK_USAGE
817	bool "Stack utilization instrumentation"
818	depends on DEBUG_KERNEL && !IA64
819	help
820	  Enables the display of the minimum amount of free stack which each
821	  task has ever had available in the sysrq-T and sysrq-P debug output.
822
823	  This option will slow down process creation somewhat.
824
825config SCHED_STACK_END_CHECK
826	bool "Detect stack corruption on calls to schedule()"
827	depends on DEBUG_KERNEL
828	default n
829	help
830	  This option checks for a stack overrun on calls to schedule().
831	  If the stack end location is found to be over written always panic as
832	  the content of the corrupted region can no longer be trusted.
833	  This is to ensure no erroneous behaviour occurs which could result in
834	  data corruption or a sporadic crash at a later stage once the region
835	  is examined. The runtime overhead introduced is minimal.
836
837config ARCH_HAS_DEBUG_VM_PGTABLE
838	bool
839	help
840	  An architecture should select this when it can successfully
841	  build and run DEBUG_VM_PGTABLE.
842
843config DEBUG_VM_IRQSOFF
844	def_bool DEBUG_VM && !PREEMPT_RT
845
846config DEBUG_VM
847	bool "Debug VM"
848	depends on DEBUG_KERNEL
849	help
850	  Enable this to turn on extended checks in the virtual-memory system
851	  that may impact performance.
852
853	  If unsure, say N.
854
855config DEBUG_VM_MAPLE_TREE
856	bool "Debug VM maple trees"
857	depends on DEBUG_VM
858	select DEBUG_MAPLE_TREE
859	help
860	  Enable VM maple tree debugging information and extra validations.
861
862	  If unsure, say N.
863
864config DEBUG_VM_RB
865	bool "Debug VM red-black trees"
866	depends on DEBUG_VM
867	help
868	  Enable VM red-black tree debugging information and extra validations.
869
870	  If unsure, say N.
871
872config DEBUG_VM_PGFLAGS
873	bool "Debug page-flags operations"
874	depends on DEBUG_VM
875	help
876	  Enables extra validation on page flags operations.
877
878	  If unsure, say N.
879
880config DEBUG_VM_PGTABLE
881	bool "Debug arch page table for semantics compliance"
882	depends on MMU
883	depends on ARCH_HAS_DEBUG_VM_PGTABLE
884	default y if DEBUG_VM
885	help
886	  This option provides a debug method which can be used to test
887	  architecture page table helper functions on various platforms in
888	  verifying if they comply with expected generic MM semantics. This
889	  will help architecture code in making sure that any changes or
890	  new additions of these helpers still conform to expected
891	  semantics of the generic MM. Platforms will have to opt in for
892	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
893
894	  If unsure, say N.
895
896config ARCH_HAS_DEBUG_VIRTUAL
897	bool
898
899config DEBUG_VIRTUAL
900	bool "Debug VM translations"
901	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
902	help
903	  Enable some costly sanity checks in virtual to page code. This can
904	  catch mistakes with virt_to_page() and friends.
905
906	  If unsure, say N.
907
908config DEBUG_NOMMU_REGIONS
909	bool "Debug the global anon/private NOMMU mapping region tree"
910	depends on DEBUG_KERNEL && !MMU
911	help
912	  This option causes the global tree of anonymous and private mapping
913	  regions to be regularly checked for invalid topology.
914
915config DEBUG_MEMORY_INIT
916	bool "Debug memory initialisation" if EXPERT
917	default !EXPERT
918	help
919	  Enable this for additional checks during memory initialisation.
920	  The sanity checks verify aspects of the VM such as the memory model
921	  and other information provided by the architecture. Verbose
922	  information will be printed at KERN_DEBUG loglevel depending
923	  on the mminit_loglevel= command-line option.
924
925	  If unsure, say Y
926
927config MEMORY_NOTIFIER_ERROR_INJECT
928	tristate "Memory hotplug notifier error injection module"
929	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
930	help
931	  This option provides the ability to inject artificial errors to
932	  memory hotplug notifier chain callbacks.  It is controlled through
933	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
934
935	  If the notifier call chain should be failed with some events
936	  notified, write the error code to "actions/<notifier event>/error".
937
938	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
939
940	  # cd /sys/kernel/debug/notifier-error-inject/memory
941	  # echo -12 > actions/MEM_GOING_OFFLINE/error
942	  # echo offline > /sys/devices/system/memory/memoryXXX/state
943	  bash: echo: write error: Cannot allocate memory
944
945	  To compile this code as a module, choose M here: the module will
946	  be called memory-notifier-error-inject.
947
948	  If unsure, say N.
949
950config DEBUG_PER_CPU_MAPS
951	bool "Debug access to per_cpu maps"
952	depends on DEBUG_KERNEL
953	depends on SMP
954	help
955	  Say Y to verify that the per_cpu map being accessed has
956	  been set up. This adds a fair amount of code to kernel memory
957	  and decreases performance.
958
959	  Say N if unsure.
960
961config DEBUG_KMAP_LOCAL
962	bool "Debug kmap_local temporary mappings"
963	depends on DEBUG_KERNEL && KMAP_LOCAL
964	help
965	  This option enables additional error checking for the kmap_local
966	  infrastructure.  Disable for production use.
967
968config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
969	bool
970
971config DEBUG_KMAP_LOCAL_FORCE_MAP
972	bool "Enforce kmap_local temporary mappings"
973	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
974	select KMAP_LOCAL
975	select DEBUG_KMAP_LOCAL
976	help
977	  This option enforces temporary mappings through the kmap_local
978	  mechanism for non-highmem pages and on non-highmem systems.
979	  Disable this for production systems!
980
981config DEBUG_HIGHMEM
982	bool "Highmem debugging"
983	depends on DEBUG_KERNEL && HIGHMEM
984	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
985	select DEBUG_KMAP_LOCAL
986	help
987	  This option enables additional error checking for high memory
988	  systems.  Disable for production systems.
989
990config HAVE_DEBUG_STACKOVERFLOW
991	bool
992
993config DEBUG_STACKOVERFLOW
994	bool "Check for stack overflows"
995	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
996	help
997	  Say Y here if you want to check for overflows of kernel, IRQ
998	  and exception stacks (if your architecture uses them). This
999	  option will show detailed messages if free stack space drops
1000	  below a certain limit.
1001
1002	  These kinds of bugs usually occur when call-chains in the
1003	  kernel get too deep, especially when interrupts are
1004	  involved.
1005
1006	  Use this in cases where you see apparently random memory
1007	  corruption, especially if it appears in 'struct thread_info'
1008
1009	  If in doubt, say "N".
1010
1011source "lib/Kconfig.kasan"
1012source "lib/Kconfig.kfence"
1013source "lib/Kconfig.kmsan"
1014
1015endmenu # "Memory Debugging"
1016
1017config DEBUG_SHIRQ
1018	bool "Debug shared IRQ handlers"
1019	depends on DEBUG_KERNEL
1020	help
1021	  Enable this to generate a spurious interrupt just before a shared
1022	  interrupt handler is deregistered (generating one when registering
1023	  is currently disabled). Drivers need to handle this correctly. Some
1024	  don't and need to be caught.
1025
1026menu "Debug Oops, Lockups and Hangs"
1027
1028config PANIC_ON_OOPS
1029	bool "Panic on Oops"
1030	help
1031	  Say Y here to enable the kernel to panic when it oopses. This
1032	  has the same effect as setting oops=panic on the kernel command
1033	  line.
1034
1035	  This feature is useful to ensure that the kernel does not do
1036	  anything erroneous after an oops which could result in data
1037	  corruption or other issues.
1038
1039	  Say N if unsure.
1040
1041config PANIC_ON_OOPS_VALUE
1042	int
1043	range 0 1
1044	default 0 if !PANIC_ON_OOPS
1045	default 1 if PANIC_ON_OOPS
1046
1047config PANIC_TIMEOUT
1048	int "panic timeout"
1049	default 0
1050	help
1051	  Set the timeout value (in seconds) until a reboot occurs when
1052	  the kernel panics. If n = 0, then we wait forever. A timeout
1053	  value n > 0 will wait n seconds before rebooting, while a timeout
1054	  value n < 0 will reboot immediately.
1055
1056config LOCKUP_DETECTOR
1057	bool
1058
1059config SOFTLOCKUP_DETECTOR
1060	bool "Detect Soft Lockups"
1061	depends on DEBUG_KERNEL && !S390
1062	select LOCKUP_DETECTOR
1063	help
1064	  Say Y here to enable the kernel to act as a watchdog to detect
1065	  soft lockups.
1066
1067	  Softlockups are bugs that cause the kernel to loop in kernel
1068	  mode for more than 20 seconds, without giving other tasks a
1069	  chance to run.  The current stack trace is displayed upon
1070	  detection and the system will stay locked up.
1071
1072config BOOTPARAM_SOFTLOCKUP_PANIC
1073	bool "Panic (Reboot) On Soft Lockups"
1074	depends on SOFTLOCKUP_DETECTOR
1075	help
1076	  Say Y here to enable the kernel to panic on "soft lockups",
1077	  which are bugs that cause the kernel to loop in kernel
1078	  mode for more than 20 seconds (configurable using the watchdog_thresh
1079	  sysctl), without giving other tasks a chance to run.
1080
1081	  The panic can be used in combination with panic_timeout,
1082	  to cause the system to reboot automatically after a
1083	  lockup has been detected. This feature is useful for
1084	  high-availability systems that have uptime guarantees and
1085	  where a lockup must be resolved ASAP.
1086
1087	  Say N if unsure.
1088
1089config HARDLOCKUP_DETECTOR_PERF
1090	bool
1091	select SOFTLOCKUP_DETECTOR
1092
1093#
1094# Enables a timestamp based low pass filter to compensate for perf based
1095# hard lockup detection which runs too fast due to turbo modes.
1096#
1097config HARDLOCKUP_CHECK_TIMESTAMP
1098	bool
1099
1100#
1101# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1102# lockup detector rather than the perf based detector.
1103#
1104config HARDLOCKUP_DETECTOR
1105	bool "Detect Hard Lockups"
1106	depends on DEBUG_KERNEL && !S390
1107	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1108	select LOCKUP_DETECTOR
1109	select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1110	help
1111	  Say Y here to enable the kernel to act as a watchdog to detect
1112	  hard lockups.
1113
1114	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1115	  for more than 10 seconds, without letting other interrupts have a
1116	  chance to run.  The current stack trace is displayed upon detection
1117	  and the system will stay locked up.
1118
1119config BOOTPARAM_HARDLOCKUP_PANIC
1120	bool "Panic (Reboot) On Hard Lockups"
1121	depends on HARDLOCKUP_DETECTOR
1122	help
1123	  Say Y here to enable the kernel to panic on "hard lockups",
1124	  which are bugs that cause the kernel to loop in kernel
1125	  mode with interrupts disabled for more than 10 seconds (configurable
1126	  using the watchdog_thresh sysctl).
1127
1128	  Say N if unsure.
1129
1130config DETECT_HUNG_TASK
1131	bool "Detect Hung Tasks"
1132	depends on DEBUG_KERNEL
1133	default SOFTLOCKUP_DETECTOR
1134	help
1135	  Say Y here to enable the kernel to detect "hung tasks",
1136	  which are bugs that cause the task to be stuck in
1137	  uninterruptible "D" state indefinitely.
1138
1139	  When a hung task is detected, the kernel will print the
1140	  current stack trace (which you should report), but the
1141	  task will stay in uninterruptible state. If lockdep is
1142	  enabled then all held locks will also be reported. This
1143	  feature has negligible overhead.
1144
1145config DEFAULT_HUNG_TASK_TIMEOUT
1146	int "Default timeout for hung task detection (in seconds)"
1147	depends on DETECT_HUNG_TASK
1148	default 120
1149	help
1150	  This option controls the default timeout (in seconds) used
1151	  to determine when a task has become non-responsive and should
1152	  be considered hung.
1153
1154	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1155	  sysctl or by writing a value to
1156	  /proc/sys/kernel/hung_task_timeout_secs.
1157
1158	  A timeout of 0 disables the check.  The default is two minutes.
1159	  Keeping the default should be fine in most cases.
1160
1161config BOOTPARAM_HUNG_TASK_PANIC
1162	bool "Panic (Reboot) On Hung Tasks"
1163	depends on DETECT_HUNG_TASK
1164	help
1165	  Say Y here to enable the kernel to panic on "hung tasks",
1166	  which are bugs that cause the kernel to leave a task stuck
1167	  in uninterruptible "D" state.
1168
1169	  The panic can be used in combination with panic_timeout,
1170	  to cause the system to reboot automatically after a
1171	  hung task has been detected. This feature is useful for
1172	  high-availability systems that have uptime guarantees and
1173	  where a hung tasks must be resolved ASAP.
1174
1175	  Say N if unsure.
1176
1177config WQ_WATCHDOG
1178	bool "Detect Workqueue Stalls"
1179	depends on DEBUG_KERNEL
1180	help
1181	  Say Y here to enable stall detection on workqueues.  If a
1182	  worker pool doesn't make forward progress on a pending work
1183	  item for over a given amount of time, 30s by default, a
1184	  warning message is printed along with dump of workqueue
1185	  state.  This can be configured through kernel parameter
1186	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1187
1188config TEST_LOCKUP
1189	tristate "Test module to generate lockups"
1190	depends on m
1191	help
1192	  This builds the "test_lockup" module that helps to make sure
1193	  that watchdogs and lockup detectors are working properly.
1194
1195	  Depending on module parameters it could emulate soft or hard
1196	  lockup, "hung task", or locking arbitrary lock for a long time.
1197	  Also it could generate series of lockups with cooling-down periods.
1198
1199	  If unsure, say N.
1200
1201endmenu # "Debug lockups and hangs"
1202
1203menu "Scheduler Debugging"
1204
1205config SCHED_DEBUG
1206	bool "Collect scheduler debugging info"
1207	depends on DEBUG_KERNEL && PROC_FS
1208	default y
1209	help
1210	  If you say Y here, the /proc/sched_debug file will be provided
1211	  that can help debug the scheduler. The runtime overhead of this
1212	  option is minimal.
1213
1214config SCHED_INFO
1215	bool
1216	default n
1217
1218config SCHEDSTATS
1219	bool "Collect scheduler statistics"
1220	depends on DEBUG_KERNEL && PROC_FS
1221	select SCHED_INFO
1222	help
1223	  If you say Y here, additional code will be inserted into the
1224	  scheduler and related routines to collect statistics about
1225	  scheduler behavior and provide them in /proc/schedstat.  These
1226	  stats may be useful for both tuning and debugging the scheduler
1227	  If you aren't debugging the scheduler or trying to tune a specific
1228	  application, you can say N to avoid the very slight overhead
1229	  this adds.
1230
1231endmenu
1232
1233config DEBUG_TIMEKEEPING
1234	bool "Enable extra timekeeping sanity checking"
1235	help
1236	  This option will enable additional timekeeping sanity checks
1237	  which may be helpful when diagnosing issues where timekeeping
1238	  problems are suspected.
1239
1240	  This may include checks in the timekeeping hotpaths, so this
1241	  option may have a (very small) performance impact to some
1242	  workloads.
1243
1244	  If unsure, say N.
1245
1246config DEBUG_PREEMPT
1247	bool "Debug preemptible kernel"
1248	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1249	help
1250	  If you say Y here then the kernel will use a debug variant of the
1251	  commonly used smp_processor_id() function and will print warnings
1252	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1253	  will detect preemption count underflows.
1254
1255	  This option has potential to introduce high runtime overhead,
1256	  depending on workload as it triggers debugging routines for each
1257	  this_cpu operation. It should only be used for debugging purposes.
1258
1259menu "Lock Debugging (spinlocks, mutexes, etc...)"
1260
1261config LOCK_DEBUGGING_SUPPORT
1262	bool
1263	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1264	default y
1265
1266config PROVE_LOCKING
1267	bool "Lock debugging: prove locking correctness"
1268	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1269	select LOCKDEP
1270	select DEBUG_SPINLOCK
1271	select DEBUG_MUTEXES if !PREEMPT_RT
1272	select DEBUG_RT_MUTEXES if RT_MUTEXES
1273	select DEBUG_RWSEMS
1274	select DEBUG_WW_MUTEX_SLOWPATH
1275	select DEBUG_LOCK_ALLOC
1276	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1277	select TRACE_IRQFLAGS
1278	default n
1279	help
1280	 This feature enables the kernel to prove that all locking
1281	 that occurs in the kernel runtime is mathematically
1282	 correct: that under no circumstance could an arbitrary (and
1283	 not yet triggered) combination of observed locking
1284	 sequences (on an arbitrary number of CPUs, running an
1285	 arbitrary number of tasks and interrupt contexts) cause a
1286	 deadlock.
1287
1288	 In short, this feature enables the kernel to report locking
1289	 related deadlocks before they actually occur.
1290
1291	 The proof does not depend on how hard and complex a
1292	 deadlock scenario would be to trigger: how many
1293	 participant CPUs, tasks and irq-contexts would be needed
1294	 for it to trigger. The proof also does not depend on
1295	 timing: if a race and a resulting deadlock is possible
1296	 theoretically (no matter how unlikely the race scenario
1297	 is), it will be proven so and will immediately be
1298	 reported by the kernel (once the event is observed that
1299	 makes the deadlock theoretically possible).
1300
1301	 If a deadlock is impossible (i.e. the locking rules, as
1302	 observed by the kernel, are mathematically correct), the
1303	 kernel reports nothing.
1304
1305	 NOTE: this feature can also be enabled for rwlocks, mutexes
1306	 and rwsems - in which case all dependencies between these
1307	 different locking variants are observed and mapped too, and
1308	 the proof of observed correctness is also maintained for an
1309	 arbitrary combination of these separate locking variants.
1310
1311	 For more details, see Documentation/locking/lockdep-design.rst.
1312
1313config PROVE_RAW_LOCK_NESTING
1314	bool "Enable raw_spinlock - spinlock nesting checks"
1315	depends on PROVE_LOCKING
1316	default n
1317	help
1318	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1319	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1320	 not violated.
1321
1322	 NOTE: There are known nesting problems. So if you enable this
1323	 option expect lockdep splats until these problems have been fully
1324	 addressed which is work in progress. This config switch allows to
1325	 identify and analyze these problems. It will be removed and the
1326	 check permanently enabled once the main issues have been fixed.
1327
1328	 If unsure, select N.
1329
1330config LOCK_STAT
1331	bool "Lock usage statistics"
1332	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1333	select LOCKDEP
1334	select DEBUG_SPINLOCK
1335	select DEBUG_MUTEXES if !PREEMPT_RT
1336	select DEBUG_RT_MUTEXES if RT_MUTEXES
1337	select DEBUG_LOCK_ALLOC
1338	default n
1339	help
1340	 This feature enables tracking lock contention points
1341
1342	 For more details, see Documentation/locking/lockstat.rst
1343
1344	 This also enables lock events required by "perf lock",
1345	 subcommand of perf.
1346	 If you want to use "perf lock", you also need to turn on
1347	 CONFIG_EVENT_TRACING.
1348
1349	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1350	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1351
1352config DEBUG_RT_MUTEXES
1353	bool "RT Mutex debugging, deadlock detection"
1354	depends on DEBUG_KERNEL && RT_MUTEXES
1355	help
1356	 This allows rt mutex semantics violations and rt mutex related
1357	 deadlocks (lockups) to be detected and reported automatically.
1358
1359config DEBUG_SPINLOCK
1360	bool "Spinlock and rw-lock debugging: basic checks"
1361	depends on DEBUG_KERNEL
1362	select UNINLINE_SPIN_UNLOCK
1363	help
1364	  Say Y here and build SMP to catch missing spinlock initialization
1365	  and certain other kinds of spinlock errors commonly made.  This is
1366	  best used in conjunction with the NMI watchdog so that spinlock
1367	  deadlocks are also debuggable.
1368
1369config DEBUG_MUTEXES
1370	bool "Mutex debugging: basic checks"
1371	depends on DEBUG_KERNEL && !PREEMPT_RT
1372	help
1373	 This feature allows mutex semantics violations to be detected and
1374	 reported.
1375
1376config DEBUG_WW_MUTEX_SLOWPATH
1377	bool "Wait/wound mutex debugging: Slowpath testing"
1378	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1379	select DEBUG_LOCK_ALLOC
1380	select DEBUG_SPINLOCK
1381	select DEBUG_MUTEXES if !PREEMPT_RT
1382	select DEBUG_RT_MUTEXES if PREEMPT_RT
1383	help
1384	 This feature enables slowpath testing for w/w mutex users by
1385	 injecting additional -EDEADLK wound/backoff cases. Together with
1386	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1387	 will test all possible w/w mutex interface abuse with the
1388	 exception of simply not acquiring all the required locks.
1389	 Note that this feature can introduce significant overhead, so
1390	 it really should not be enabled in a production or distro kernel,
1391	 even a debug kernel.  If you are a driver writer, enable it.  If
1392	 you are a distro, do not.
1393
1394config DEBUG_RWSEMS
1395	bool "RW Semaphore debugging: basic checks"
1396	depends on DEBUG_KERNEL
1397	help
1398	  This debugging feature allows mismatched rw semaphore locks
1399	  and unlocks to be detected and reported.
1400
1401config DEBUG_LOCK_ALLOC
1402	bool "Lock debugging: detect incorrect freeing of live locks"
1403	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1404	select DEBUG_SPINLOCK
1405	select DEBUG_MUTEXES if !PREEMPT_RT
1406	select DEBUG_RT_MUTEXES if RT_MUTEXES
1407	select LOCKDEP
1408	help
1409	 This feature will check whether any held lock (spinlock, rwlock,
1410	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1411	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1412	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1413	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1414	 held during task exit.
1415
1416config LOCKDEP
1417	bool
1418	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1419	select STACKTRACE
1420	select KALLSYMS
1421	select KALLSYMS_ALL
1422
1423config LOCKDEP_SMALL
1424	bool
1425
1426config LOCKDEP_BITS
1427	int "Bitsize for MAX_LOCKDEP_ENTRIES"
1428	depends on LOCKDEP && !LOCKDEP_SMALL
1429	range 10 30
1430	default 15
1431	help
1432	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1433
1434config LOCKDEP_CHAINS_BITS
1435	int "Bitsize for MAX_LOCKDEP_CHAINS"
1436	depends on LOCKDEP && !LOCKDEP_SMALL
1437	range 10 30
1438	default 16
1439	help
1440	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1441
1442config LOCKDEP_STACK_TRACE_BITS
1443	int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1444	depends on LOCKDEP && !LOCKDEP_SMALL
1445	range 10 30
1446	default 19
1447	help
1448	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1449
1450config LOCKDEP_STACK_TRACE_HASH_BITS
1451	int "Bitsize for STACK_TRACE_HASH_SIZE"
1452	depends on LOCKDEP && !LOCKDEP_SMALL
1453	range 10 30
1454	default 14
1455	help
1456	  Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1457
1458config LOCKDEP_CIRCULAR_QUEUE_BITS
1459	int "Bitsize for elements in circular_queue struct"
1460	depends on LOCKDEP
1461	range 10 30
1462	default 12
1463	help
1464	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1465
1466config DEBUG_LOCKDEP
1467	bool "Lock dependency engine debugging"
1468	depends on DEBUG_KERNEL && LOCKDEP
1469	select DEBUG_IRQFLAGS
1470	help
1471	  If you say Y here, the lock dependency engine will do
1472	  additional runtime checks to debug itself, at the price
1473	  of more runtime overhead.
1474
1475config DEBUG_ATOMIC_SLEEP
1476	bool "Sleep inside atomic section checking"
1477	select PREEMPT_COUNT
1478	depends on DEBUG_KERNEL
1479	depends on !ARCH_NO_PREEMPT
1480	help
1481	  If you say Y here, various routines which may sleep will become very
1482	  noisy if they are called inside atomic sections: when a spinlock is
1483	  held, inside an rcu read side critical section, inside preempt disabled
1484	  sections, inside an interrupt, etc...
1485
1486config DEBUG_LOCKING_API_SELFTESTS
1487	bool "Locking API boot-time self-tests"
1488	depends on DEBUG_KERNEL
1489	help
1490	  Say Y here if you want the kernel to run a short self-test during
1491	  bootup. The self-test checks whether common types of locking bugs
1492	  are detected by debugging mechanisms or not. (if you disable
1493	  lock debugging then those bugs won't be detected of course.)
1494	  The following locking APIs are covered: spinlocks, rwlocks,
1495	  mutexes and rwsems.
1496
1497config LOCK_TORTURE_TEST
1498	tristate "torture tests for locking"
1499	depends on DEBUG_KERNEL
1500	select TORTURE_TEST
1501	help
1502	  This option provides a kernel module that runs torture tests
1503	  on kernel locking primitives.  The kernel module may be built
1504	  after the fact on the running kernel to be tested, if desired.
1505
1506	  Say Y here if you want kernel locking-primitive torture tests
1507	  to be built into the kernel.
1508	  Say M if you want these torture tests to build as a module.
1509	  Say N if you are unsure.
1510
1511config WW_MUTEX_SELFTEST
1512	tristate "Wait/wound mutex selftests"
1513	help
1514	  This option provides a kernel module that runs tests on the
1515	  on the struct ww_mutex locking API.
1516
1517	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1518	  with this test harness.
1519
1520	  Say M if you want these self tests to build as a module.
1521	  Say N if you are unsure.
1522
1523config SCF_TORTURE_TEST
1524	tristate "torture tests for smp_call_function*()"
1525	depends on DEBUG_KERNEL
1526	select TORTURE_TEST
1527	help
1528	  This option provides a kernel module that runs torture tests
1529	  on the smp_call_function() family of primitives.  The kernel
1530	  module may be built after the fact on the running kernel to
1531	  be tested, if desired.
1532
1533config CSD_LOCK_WAIT_DEBUG
1534	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1535	depends on DEBUG_KERNEL
1536	depends on 64BIT
1537	default n
1538	help
1539	  This option enables debug prints when CPUs are slow to respond
1540	  to the smp_call_function*() IPI wrappers.  These debug prints
1541	  include the IPI handler function currently executing (if any)
1542	  and relevant stack traces.
1543
1544endmenu # lock debugging
1545
1546config TRACE_IRQFLAGS
1547	depends on TRACE_IRQFLAGS_SUPPORT
1548	bool
1549	help
1550	  Enables hooks to interrupt enabling and disabling for
1551	  either tracing or lock debugging.
1552
1553config TRACE_IRQFLAGS_NMI
1554	def_bool y
1555	depends on TRACE_IRQFLAGS
1556	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1557
1558config DEBUG_IRQFLAGS
1559	bool "Debug IRQ flag manipulation"
1560	help
1561	  Enables checks for potentially unsafe enabling or disabling of
1562	  interrupts, such as calling raw_local_irq_restore() when interrupts
1563	  are enabled.
1564
1565config STACKTRACE
1566	bool "Stack backtrace support"
1567	depends on STACKTRACE_SUPPORT
1568	help
1569	  This option causes the kernel to create a /proc/pid/stack for
1570	  every process, showing its current stack trace.
1571	  It is also used by various kernel debugging features that require
1572	  stack trace generation.
1573
1574config WARN_ALL_UNSEEDED_RANDOM
1575	bool "Warn for all uses of unseeded randomness"
1576	default n
1577	help
1578	  Some parts of the kernel contain bugs relating to their use of
1579	  cryptographically secure random numbers before it's actually possible
1580	  to generate those numbers securely. This setting ensures that these
1581	  flaws don't go unnoticed, by enabling a message, should this ever
1582	  occur. This will allow people with obscure setups to know when things
1583	  are going wrong, so that they might contact developers about fixing
1584	  it.
1585
1586	  Unfortunately, on some models of some architectures getting
1587	  a fully seeded CRNG is extremely difficult, and so this can
1588	  result in dmesg getting spammed for a surprisingly long
1589	  time.  This is really bad from a security perspective, and
1590	  so architecture maintainers really need to do what they can
1591	  to get the CRNG seeded sooner after the system is booted.
1592	  However, since users cannot do anything actionable to
1593	  address this, by default this option is disabled.
1594
1595	  Say Y here if you want to receive warnings for all uses of
1596	  unseeded randomness.  This will be of use primarily for
1597	  those developers interested in improving the security of
1598	  Linux kernels running on their architecture (or
1599	  subarchitecture).
1600
1601config DEBUG_KOBJECT
1602	bool "kobject debugging"
1603	depends on DEBUG_KERNEL
1604	help
1605	  If you say Y here, some extra kobject debugging messages will be sent
1606	  to the syslog.
1607
1608config DEBUG_KOBJECT_RELEASE
1609	bool "kobject release debugging"
1610	depends on DEBUG_OBJECTS_TIMERS
1611	help
1612	  kobjects are reference counted objects.  This means that their
1613	  last reference count put is not predictable, and the kobject can
1614	  live on past the point at which a driver decides to drop its
1615	  initial reference to the kobject gained on allocation.  An
1616	  example of this would be a struct device which has just been
1617	  unregistered.
1618
1619	  However, some buggy drivers assume that after such an operation,
1620	  the memory backing the kobject can be immediately freed.  This
1621	  goes completely against the principles of a refcounted object.
1622
1623	  If you say Y here, the kernel will delay the release of kobjects
1624	  on the last reference count to improve the visibility of this
1625	  kind of kobject release bug.
1626
1627config HAVE_DEBUG_BUGVERBOSE
1628	bool
1629
1630menu "Debug kernel data structures"
1631
1632config DEBUG_LIST
1633	bool "Debug linked list manipulation"
1634	depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1635	help
1636	  Enable this to turn on extended checks in the linked-list
1637	  walking routines.
1638
1639	  If unsure, say N.
1640
1641config DEBUG_PLIST
1642	bool "Debug priority linked list manipulation"
1643	depends on DEBUG_KERNEL
1644	help
1645	  Enable this to turn on extended checks in the priority-ordered
1646	  linked-list (plist) walking routines.  This checks the entire
1647	  list multiple times during each manipulation.
1648
1649	  If unsure, say N.
1650
1651config DEBUG_SG
1652	bool "Debug SG table operations"
1653	depends on DEBUG_KERNEL
1654	help
1655	  Enable this to turn on checks on scatter-gather tables. This can
1656	  help find problems with drivers that do not properly initialize
1657	  their sg tables.
1658
1659	  If unsure, say N.
1660
1661config DEBUG_NOTIFIERS
1662	bool "Debug notifier call chains"
1663	depends on DEBUG_KERNEL
1664	help
1665	  Enable this to turn on sanity checking for notifier call chains.
1666	  This is most useful for kernel developers to make sure that
1667	  modules properly unregister themselves from notifier chains.
1668	  This is a relatively cheap check but if you care about maximum
1669	  performance, say N.
1670
1671config BUG_ON_DATA_CORRUPTION
1672	bool "Trigger a BUG when data corruption is detected"
1673	select DEBUG_LIST
1674	help
1675	  Select this option if the kernel should BUG when it encounters
1676	  data corruption in kernel memory structures when they get checked
1677	  for validity.
1678
1679	  If unsure, say N.
1680
1681config DEBUG_MAPLE_TREE
1682	bool "Debug maple trees"
1683	depends on DEBUG_KERNEL
1684	help
1685	  Enable maple tree debugging information and extra validations.
1686
1687	  If unsure, say N.
1688
1689endmenu
1690
1691config DEBUG_CREDENTIALS
1692	bool "Debug credential management"
1693	depends on DEBUG_KERNEL
1694	help
1695	  Enable this to turn on some debug checking for credential
1696	  management.  The additional code keeps track of the number of
1697	  pointers from task_structs to any given cred struct, and checks to
1698	  see that this number never exceeds the usage count of the cred
1699	  struct.
1700
1701	  Furthermore, if SELinux is enabled, this also checks that the
1702	  security pointer in the cred struct is never seen to be invalid.
1703
1704	  If unsure, say N.
1705
1706source "kernel/rcu/Kconfig.debug"
1707
1708config DEBUG_WQ_FORCE_RR_CPU
1709	bool "Force round-robin CPU selection for unbound work items"
1710	depends on DEBUG_KERNEL
1711	default n
1712	help
1713	  Workqueue used to implicitly guarantee that work items queued
1714	  without explicit CPU specified are put on the local CPU.  This
1715	  guarantee is no longer true and while local CPU is still
1716	  preferred work items may be put on foreign CPUs.  Kernel
1717	  parameter "workqueue.debug_force_rr_cpu" is added to force
1718	  round-robin CPU selection to flush out usages which depend on the
1719	  now broken guarantee.  This config option enables the debug
1720	  feature by default.  When enabled, memory and cache locality will
1721	  be impacted.
1722
1723config CPU_HOTPLUG_STATE_CONTROL
1724	bool "Enable CPU hotplug state control"
1725	depends on DEBUG_KERNEL
1726	depends on HOTPLUG_CPU
1727	default n
1728	help
1729	  Allows to write steps between "offline" and "online" to the CPUs
1730	  sysfs target file so states can be stepped granular. This is a debug
1731	  option for now as the hotplug machinery cannot be stopped and
1732	  restarted at arbitrary points yet.
1733
1734	  Say N if your are unsure.
1735
1736config LATENCYTOP
1737	bool "Latency measuring infrastructure"
1738	depends on DEBUG_KERNEL
1739	depends on STACKTRACE_SUPPORT
1740	depends on PROC_FS
1741	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1742	select KALLSYMS
1743	select KALLSYMS_ALL
1744	select STACKTRACE
1745	select SCHEDSTATS
1746	help
1747	  Enable this option if you want to use the LatencyTOP tool
1748	  to find out which userspace is blocking on what kernel operations.
1749
1750config DEBUG_CGROUP_REF
1751	bool "Disable inlining of cgroup css reference count functions"
1752	depends on DEBUG_KERNEL
1753	depends on CGROUPS
1754	depends on KPROBES
1755	default n
1756	help
1757	  Force cgroup css reference count functions to not be inlined so
1758	  that they can be kprobed for debugging.
1759
1760source "kernel/trace/Kconfig"
1761
1762config PROVIDE_OHCI1394_DMA_INIT
1763	bool "Remote debugging over FireWire early on boot"
1764	depends on PCI && X86
1765	help
1766	  If you want to debug problems which hang or crash the kernel early
1767	  on boot and the crashing machine has a FireWire port, you can use
1768	  this feature to remotely access the memory of the crashed machine
1769	  over FireWire. This employs remote DMA as part of the OHCI1394
1770	  specification which is now the standard for FireWire controllers.
1771
1772	  With remote DMA, you can monitor the printk buffer remotely using
1773	  firescope and access all memory below 4GB using fireproxy from gdb.
1774	  Even controlling a kernel debugger is possible using remote DMA.
1775
1776	  Usage:
1777
1778	  If ohci1394_dma=early is used as boot parameter, it will initialize
1779	  all OHCI1394 controllers which are found in the PCI config space.
1780
1781	  As all changes to the FireWire bus such as enabling and disabling
1782	  devices cause a bus reset and thereby disable remote DMA for all
1783	  devices, be sure to have the cable plugged and FireWire enabled on
1784	  the debugging host before booting the debug target for debugging.
1785
1786	  This code (~1k) is freed after boot. By then, the firewire stack
1787	  in charge of the OHCI-1394 controllers should be used instead.
1788
1789	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1790
1791source "samples/Kconfig"
1792
1793config ARCH_HAS_DEVMEM_IS_ALLOWED
1794	bool
1795
1796config STRICT_DEVMEM
1797	bool "Filter access to /dev/mem"
1798	depends on MMU && DEVMEM
1799	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1800	default y if PPC || X86 || ARM64
1801	help
1802	  If this option is disabled, you allow userspace (root) access to all
1803	  of memory, including kernel and userspace memory. Accidental
1804	  access to this is obviously disastrous, but specific access can
1805	  be used by people debugging the kernel. Note that with PAT support
1806	  enabled, even in this case there are restrictions on /dev/mem
1807	  use due to the cache aliasing requirements.
1808
1809	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1810	  file only allows userspace access to PCI space and the BIOS code and
1811	  data regions.  This is sufficient for dosemu and X and all common
1812	  users of /dev/mem.
1813
1814	  If in doubt, say Y.
1815
1816config IO_STRICT_DEVMEM
1817	bool "Filter I/O access to /dev/mem"
1818	depends on STRICT_DEVMEM
1819	help
1820	  If this option is disabled, you allow userspace (root) access to all
1821	  io-memory regardless of whether a driver is actively using that
1822	  range.  Accidental access to this is obviously disastrous, but
1823	  specific access can be used by people debugging kernel drivers.
1824
1825	  If this option is switched on, the /dev/mem file only allows
1826	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1827	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1828	  if the driver using a given range cannot be disabled.
1829
1830	  If in doubt, say Y.
1831
1832menu "$(SRCARCH) Debugging"
1833
1834source "arch/$(SRCARCH)/Kconfig.debug"
1835
1836endmenu
1837
1838menu "Kernel Testing and Coverage"
1839
1840source "lib/kunit/Kconfig"
1841
1842config NOTIFIER_ERROR_INJECTION
1843	tristate "Notifier error injection"
1844	depends on DEBUG_KERNEL
1845	select DEBUG_FS
1846	help
1847	  This option provides the ability to inject artificial errors to
1848	  specified notifier chain callbacks. It is useful to test the error
1849	  handling of notifier call chain failures.
1850
1851	  Say N if unsure.
1852
1853config PM_NOTIFIER_ERROR_INJECT
1854	tristate "PM notifier error injection module"
1855	depends on PM && NOTIFIER_ERROR_INJECTION
1856	default m if PM_DEBUG
1857	help
1858	  This option provides the ability to inject artificial errors to
1859	  PM notifier chain callbacks.  It is controlled through debugfs
1860	  interface /sys/kernel/debug/notifier-error-inject/pm
1861
1862	  If the notifier call chain should be failed with some events
1863	  notified, write the error code to "actions/<notifier event>/error".
1864
1865	  Example: Inject PM suspend error (-12 = -ENOMEM)
1866
1867	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1868	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1869	  # echo mem > /sys/power/state
1870	  bash: echo: write error: Cannot allocate memory
1871
1872	  To compile this code as a module, choose M here: the module will
1873	  be called pm-notifier-error-inject.
1874
1875	  If unsure, say N.
1876
1877config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1878	tristate "OF reconfig notifier error injection module"
1879	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1880	help
1881	  This option provides the ability to inject artificial errors to
1882	  OF reconfig notifier chain callbacks.  It is controlled
1883	  through debugfs interface under
1884	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1885
1886	  If the notifier call chain should be failed with some events
1887	  notified, write the error code to "actions/<notifier event>/error".
1888
1889	  To compile this code as a module, choose M here: the module will
1890	  be called of-reconfig-notifier-error-inject.
1891
1892	  If unsure, say N.
1893
1894config NETDEV_NOTIFIER_ERROR_INJECT
1895	tristate "Netdev notifier error injection module"
1896	depends on NET && NOTIFIER_ERROR_INJECTION
1897	help
1898	  This option provides the ability to inject artificial errors to
1899	  netdevice notifier chain callbacks.  It is controlled through debugfs
1900	  interface /sys/kernel/debug/notifier-error-inject/netdev
1901
1902	  If the notifier call chain should be failed with some events
1903	  notified, write the error code to "actions/<notifier event>/error".
1904
1905	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
1906
1907	  # cd /sys/kernel/debug/notifier-error-inject/netdev
1908	  # echo -22 > actions/NETDEV_CHANGEMTU/error
1909	  # ip link set eth0 mtu 1024
1910	  RTNETLINK answers: Invalid argument
1911
1912	  To compile this code as a module, choose M here: the module will
1913	  be called netdev-notifier-error-inject.
1914
1915	  If unsure, say N.
1916
1917config FUNCTION_ERROR_INJECTION
1918	bool "Fault-injections of functions"
1919	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1920	help
1921	  Add fault injections into various functions that are annotated with
1922	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1923	  value of theses functions. This is useful to test error paths of code.
1924
1925	  If unsure, say N
1926
1927config FAULT_INJECTION
1928	bool "Fault-injection framework"
1929	depends on DEBUG_KERNEL
1930	help
1931	  Provide fault-injection framework.
1932	  For more details, see Documentation/fault-injection/.
1933
1934config FAILSLAB
1935	bool "Fault-injection capability for kmalloc"
1936	depends on FAULT_INJECTION
1937	depends on SLAB || SLUB
1938	help
1939	  Provide fault-injection capability for kmalloc.
1940
1941config FAIL_PAGE_ALLOC
1942	bool "Fault-injection capability for alloc_pages()"
1943	depends on FAULT_INJECTION
1944	help
1945	  Provide fault-injection capability for alloc_pages().
1946
1947config FAULT_INJECTION_USERCOPY
1948	bool "Fault injection capability for usercopy functions"
1949	depends on FAULT_INJECTION
1950	help
1951	  Provides fault-injection capability to inject failures
1952	  in usercopy functions (copy_from_user(), get_user(), ...).
1953
1954config FAIL_MAKE_REQUEST
1955	bool "Fault-injection capability for disk IO"
1956	depends on FAULT_INJECTION && BLOCK
1957	help
1958	  Provide fault-injection capability for disk IO.
1959
1960config FAIL_IO_TIMEOUT
1961	bool "Fault-injection capability for faking disk interrupts"
1962	depends on FAULT_INJECTION && BLOCK
1963	help
1964	  Provide fault-injection capability on end IO handling. This
1965	  will make the block layer "forget" an interrupt as configured,
1966	  thus exercising the error handling.
1967
1968	  Only works with drivers that use the generic timeout handling,
1969	  for others it won't do anything.
1970
1971config FAIL_FUTEX
1972	bool "Fault-injection capability for futexes"
1973	select DEBUG_FS
1974	depends on FAULT_INJECTION && FUTEX
1975	help
1976	  Provide fault-injection capability for futexes.
1977
1978config FAULT_INJECTION_DEBUG_FS
1979	bool "Debugfs entries for fault-injection capabilities"
1980	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1981	help
1982	  Enable configuration of fault-injection capabilities via debugfs.
1983
1984config FAIL_FUNCTION
1985	bool "Fault-injection capability for functions"
1986	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1987	help
1988	  Provide function-based fault-injection capability.
1989	  This will allow you to override a specific function with a return
1990	  with given return value. As a result, function caller will see
1991	  an error value and have to handle it. This is useful to test the
1992	  error handling in various subsystems.
1993
1994config FAIL_MMC_REQUEST
1995	bool "Fault-injection capability for MMC IO"
1996	depends on FAULT_INJECTION_DEBUG_FS && MMC
1997	help
1998	  Provide fault-injection capability for MMC IO.
1999	  This will make the mmc core return data errors. This is
2000	  useful to test the error handling in the mmc block device
2001	  and to test how the mmc host driver handles retries from
2002	  the block device.
2003
2004config FAIL_SUNRPC
2005	bool "Fault-injection capability for SunRPC"
2006	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2007	help
2008	  Provide fault-injection capability for SunRPC and
2009	  its consumers.
2010
2011config FAULT_INJECTION_STACKTRACE_FILTER
2012	bool "stacktrace filter for fault-injection capabilities"
2013	depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2014	select STACKTRACE
2015	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2016	help
2017	  Provide stacktrace filter for fault-injection capabilities
2018
2019config ARCH_HAS_KCOV
2020	bool
2021	help
2022	  An architecture should select this when it can successfully
2023	  build and run with CONFIG_KCOV. This typically requires
2024	  disabling instrumentation for some early boot code.
2025
2026config CC_HAS_SANCOV_TRACE_PC
2027	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2028
2029
2030config KCOV
2031	bool "Code coverage for fuzzing"
2032	depends on ARCH_HAS_KCOV
2033	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2034	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2035		   GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2036	select DEBUG_FS
2037	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2038	select OBJTOOL if HAVE_NOINSTR_HACK
2039	help
2040	  KCOV exposes kernel code coverage information in a form suitable
2041	  for coverage-guided fuzzing (randomized testing).
2042
2043	  If RANDOMIZE_BASE is enabled, PC values will not be stable across
2044	  different machines and across reboots. If you need stable PC values,
2045	  disable RANDOMIZE_BASE.
2046
2047	  For more details, see Documentation/dev-tools/kcov.rst.
2048
2049config KCOV_ENABLE_COMPARISONS
2050	bool "Enable comparison operands collection by KCOV"
2051	depends on KCOV
2052	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2053	help
2054	  KCOV also exposes operands of every comparison in the instrumented
2055	  code along with operand sizes and PCs of the comparison instructions.
2056	  These operands can be used by fuzzing engines to improve the quality
2057	  of fuzzing coverage.
2058
2059config KCOV_INSTRUMENT_ALL
2060	bool "Instrument all code by default"
2061	depends on KCOV
2062	default y
2063	help
2064	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2065	  then you will want to instrument the whole kernel and you should
2066	  say y here. If you are doing more targeted fuzzing (like e.g.
2067	  filesystem fuzzing with AFL) then you will want to enable coverage
2068	  for more specific subsets of files, and should say n here.
2069
2070config KCOV_IRQ_AREA_SIZE
2071	hex "Size of interrupt coverage collection area in words"
2072	depends on KCOV
2073	default 0x40000
2074	help
2075	  KCOV uses preallocated per-cpu areas to collect coverage from
2076	  soft interrupts. This specifies the size of those areas in the
2077	  number of unsigned long words.
2078
2079menuconfig RUNTIME_TESTING_MENU
2080	bool "Runtime Testing"
2081	def_bool y
2082
2083if RUNTIME_TESTING_MENU
2084
2085config TEST_DHRY
2086	tristate "Dhrystone benchmark test"
2087	help
2088	  Enable this to include the Dhrystone 2.1 benchmark.  This test
2089	  calculates the number of Dhrystones per second, and the number of
2090	  DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2091	  by 1757 (the number of Dhrystones per second obtained on the VAX
2092	  11/780, nominally a 1 MIPS machine).
2093
2094	  To run the benchmark, it needs to be enabled explicitly, either from
2095	  the kernel command line (when built-in), or from userspace (when
2096	  built-in or modular.
2097
2098	  Run once during kernel boot:
2099
2100	      test_dhry.run
2101
2102	  Set number of iterations from kernel command line:
2103
2104	      test_dhry.iterations=<n>
2105
2106	  Set number of iterations from userspace:
2107
2108	      echo <n> > /sys/module/test_dhry/parameters/iterations
2109
2110	  Trigger manual run from userspace:
2111
2112	      echo y > /sys/module/test_dhry/parameters/run
2113
2114	  If the number of iterations is <= 0, the test will devise a suitable
2115	  number of iterations (test runs for at least 2s) automatically.
2116	  This process takes ca. 4s.
2117
2118	  If unsure, say N.
2119
2120config LKDTM
2121	tristate "Linux Kernel Dump Test Tool Module"
2122	depends on DEBUG_FS
2123	help
2124	This module enables testing of the different dumping mechanisms by
2125	inducing system failures at predefined crash points.
2126	If you don't need it: say N
2127	Choose M here to compile this code as a module. The module will be
2128	called lkdtm.
2129
2130	Documentation on how to use the module can be found in
2131	Documentation/fault-injection/provoke-crashes.rst
2132
2133config CPUMASK_KUNIT_TEST
2134	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2135	depends on KUNIT
2136	default KUNIT_ALL_TESTS
2137	help
2138	  Enable to turn on cpumask tests, running at boot or module load time.
2139
2140	  For more information on KUnit and unit tests in general, please refer
2141	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2142
2143	  If unsure, say N.
2144
2145config TEST_LIST_SORT
2146	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2147	depends on KUNIT
2148	default KUNIT_ALL_TESTS
2149	help
2150	  Enable this to turn on 'list_sort()' function test. This test is
2151	  executed only once during system boot (so affects only boot time),
2152	  or at module load time.
2153
2154	  If unsure, say N.
2155
2156config TEST_MIN_HEAP
2157	tristate "Min heap test"
2158	depends on DEBUG_KERNEL || m
2159	help
2160	  Enable this to turn on min heap function tests. This test is
2161	  executed only once during system boot (so affects only boot time),
2162	  or at module load time.
2163
2164	  If unsure, say N.
2165
2166config TEST_SORT
2167	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2168	depends on KUNIT
2169	default KUNIT_ALL_TESTS
2170	help
2171	  This option enables the self-test function of 'sort()' at boot,
2172	  or at module load time.
2173
2174	  If unsure, say N.
2175
2176config TEST_DIV64
2177	tristate "64bit/32bit division and modulo test"
2178	depends on DEBUG_KERNEL || m
2179	help
2180	  Enable this to turn on 'do_div()' function test. This test is
2181	  executed only once during system boot (so affects only boot time),
2182	  or at module load time.
2183
2184	  If unsure, say N.
2185
2186config KPROBES_SANITY_TEST
2187	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2188	depends on DEBUG_KERNEL
2189	depends on KPROBES
2190	depends on KUNIT
2191	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2192	default KUNIT_ALL_TESTS
2193	help
2194	  This option provides for testing basic kprobes functionality on
2195	  boot. Samples of kprobe and kretprobe are inserted and
2196	  verified for functionality.
2197
2198	  Say N if you are unsure.
2199
2200config FPROBE_SANITY_TEST
2201	bool "Self test for fprobe"
2202	depends on DEBUG_KERNEL
2203	depends on FPROBE
2204	depends on KUNIT=y
2205	help
2206	  This option will enable testing the fprobe when the system boot.
2207	  A series of tests are made to verify that the fprobe is functioning
2208	  properly.
2209
2210	  Say N if you are unsure.
2211
2212config BACKTRACE_SELF_TEST
2213	tristate "Self test for the backtrace code"
2214	depends on DEBUG_KERNEL
2215	help
2216	  This option provides a kernel module that can be used to test
2217	  the kernel stack backtrace code. This option is not useful
2218	  for distributions or general kernels, but only for kernel
2219	  developers working on architecture code.
2220
2221	  Note that if you want to also test saved backtraces, you will
2222	  have to enable STACKTRACE as well.
2223
2224	  Say N if you are unsure.
2225
2226config TEST_REF_TRACKER
2227	tristate "Self test for reference tracker"
2228	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2229	select REF_TRACKER
2230	help
2231	  This option provides a kernel module performing tests
2232	  using reference tracker infrastructure.
2233
2234	  Say N if you are unsure.
2235
2236config RBTREE_TEST
2237	tristate "Red-Black tree test"
2238	depends on DEBUG_KERNEL
2239	help
2240	  A benchmark measuring the performance of the rbtree library.
2241	  Also includes rbtree invariant checks.
2242
2243config REED_SOLOMON_TEST
2244	tristate "Reed-Solomon library test"
2245	depends on DEBUG_KERNEL || m
2246	select REED_SOLOMON
2247	select REED_SOLOMON_ENC16
2248	select REED_SOLOMON_DEC16
2249	help
2250	  This option enables the self-test function of rslib at boot,
2251	  or at module load time.
2252
2253	  If unsure, say N.
2254
2255config INTERVAL_TREE_TEST
2256	tristate "Interval tree test"
2257	depends on DEBUG_KERNEL
2258	select INTERVAL_TREE
2259	help
2260	  A benchmark measuring the performance of the interval tree library
2261
2262config PERCPU_TEST
2263	tristate "Per cpu operations test"
2264	depends on m && DEBUG_KERNEL
2265	help
2266	  Enable this option to build test module which validates per-cpu
2267	  operations.
2268
2269	  If unsure, say N.
2270
2271config ATOMIC64_SELFTEST
2272	tristate "Perform an atomic64_t self-test"
2273	help
2274	  Enable this option to test the atomic64_t functions at boot or
2275	  at module load time.
2276
2277	  If unsure, say N.
2278
2279config ASYNC_RAID6_TEST
2280	tristate "Self test for hardware accelerated raid6 recovery"
2281	depends on ASYNC_RAID6_RECOV
2282	select ASYNC_MEMCPY
2283	help
2284	  This is a one-shot self test that permutes through the
2285	  recovery of all the possible two disk failure scenarios for a
2286	  N-disk array.  Recovery is performed with the asynchronous
2287	  raid6 recovery routines, and will optionally use an offload
2288	  engine if one is available.
2289
2290	  If unsure, say N.
2291
2292config TEST_HEXDUMP
2293	tristate "Test functions located in the hexdump module at runtime"
2294
2295config STRING_SELFTEST
2296	tristate "Test string functions at runtime"
2297
2298config TEST_STRING_HELPERS
2299	tristate "Test functions located in the string_helpers module at runtime"
2300
2301config TEST_KSTRTOX
2302	tristate "Test kstrto*() family of functions at runtime"
2303
2304config TEST_PRINTF
2305	tristate "Test printf() family of functions at runtime"
2306
2307config TEST_SCANF
2308	tristate "Test scanf() family of functions at runtime"
2309
2310config TEST_BITMAP
2311	tristate "Test bitmap_*() family of functions at runtime"
2312	help
2313	  Enable this option to test the bitmap functions at boot.
2314
2315	  If unsure, say N.
2316
2317config TEST_UUID
2318	tristate "Test functions located in the uuid module at runtime"
2319
2320config TEST_XARRAY
2321	tristate "Test the XArray code at runtime"
2322
2323config TEST_MAPLE_TREE
2324	depends on DEBUG_KERNEL
2325	select DEBUG_MAPLE_TREE
2326	tristate "Test the Maple Tree code at runtime"
2327
2328config TEST_RHASHTABLE
2329	tristate "Perform selftest on resizable hash table"
2330	help
2331	  Enable this option to test the rhashtable functions at boot.
2332
2333	  If unsure, say N.
2334
2335config TEST_IDA
2336	tristate "Perform selftest on IDA functions"
2337
2338config TEST_PARMAN
2339	tristate "Perform selftest on priority array manager"
2340	depends on PARMAN
2341	help
2342	  Enable this option to test priority array manager on boot
2343	  (or module load).
2344
2345	  If unsure, say N.
2346
2347config TEST_IRQ_TIMINGS
2348	bool "IRQ timings selftest"
2349	depends on IRQ_TIMINGS
2350	help
2351	  Enable this option to test the irq timings code on boot.
2352
2353	  If unsure, say N.
2354
2355config TEST_LKM
2356	tristate "Test module loading with 'hello world' module"
2357	depends on m
2358	help
2359	  This builds the "test_module" module that emits "Hello, world"
2360	  on printk when loaded. It is designed to be used for basic
2361	  evaluation of the module loading subsystem (for example when
2362	  validating module verification). It lacks any extra dependencies,
2363	  and will not normally be loaded by the system unless explicitly
2364	  requested by name.
2365
2366	  If unsure, say N.
2367
2368config TEST_BITOPS
2369	tristate "Test module for compilation of bitops operations"
2370	depends on m
2371	help
2372	  This builds the "test_bitops" module that is much like the
2373	  TEST_LKM module except that it does a basic exercise of the
2374	  set/clear_bit macros and get_count_order/long to make sure there are
2375	  no compiler warnings from C=1 sparse checker or -Wextra
2376	  compilations. It has no dependencies and doesn't run or load unless
2377	  explicitly requested by name.  for example: modprobe test_bitops.
2378
2379	  If unsure, say N.
2380
2381config TEST_VMALLOC
2382	tristate "Test module for stress/performance analysis of vmalloc allocator"
2383	default n
2384       depends on MMU
2385	depends on m
2386	help
2387	  This builds the "test_vmalloc" module that should be used for
2388	  stress and performance analysis. So, any new change for vmalloc
2389	  subsystem can be evaluated from performance and stability point
2390	  of view.
2391
2392	  If unsure, say N.
2393
2394config TEST_USER_COPY
2395	tristate "Test user/kernel boundary protections"
2396	depends on m
2397	help
2398	  This builds the "test_user_copy" module that runs sanity checks
2399	  on the copy_to/from_user infrastructure, making sure basic
2400	  user/kernel boundary testing is working. If it fails to load,
2401	  a regression has been detected in the user/kernel memory boundary
2402	  protections.
2403
2404	  If unsure, say N.
2405
2406config TEST_BPF
2407	tristate "Test BPF filter functionality"
2408	depends on m && NET
2409	help
2410	  This builds the "test_bpf" module that runs various test vectors
2411	  against the BPF interpreter or BPF JIT compiler depending on the
2412	  current setting. This is in particular useful for BPF JIT compiler
2413	  development, but also to run regression tests against changes in
2414	  the interpreter code. It also enables test stubs for eBPF maps and
2415	  verifier used by user space verifier testsuite.
2416
2417	  If unsure, say N.
2418
2419config TEST_BLACKHOLE_DEV
2420	tristate "Test blackhole netdev functionality"
2421	depends on m && NET
2422	help
2423	  This builds the "test_blackhole_dev" module that validates the
2424	  data path through this blackhole netdev.
2425
2426	  If unsure, say N.
2427
2428config FIND_BIT_BENCHMARK
2429	tristate "Test find_bit functions"
2430	help
2431	  This builds the "test_find_bit" module that measure find_*_bit()
2432	  functions performance.
2433
2434	  If unsure, say N.
2435
2436config TEST_FIRMWARE
2437	tristate "Test firmware loading via userspace interface"
2438	depends on FW_LOADER
2439	help
2440	  This builds the "test_firmware" module that creates a userspace
2441	  interface for testing firmware loading. This can be used to
2442	  control the triggering of firmware loading without needing an
2443	  actual firmware-using device. The contents can be rechecked by
2444	  userspace.
2445
2446	  If unsure, say N.
2447
2448config TEST_SYSCTL
2449	tristate "sysctl test driver"
2450	depends on PROC_SYSCTL
2451	help
2452	  This builds the "test_sysctl" module. This driver enables to test the
2453	  proc sysctl interfaces available to drivers safely without affecting
2454	  production knobs which might alter system functionality.
2455
2456	  If unsure, say N.
2457
2458config BITFIELD_KUNIT
2459	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2460	depends on KUNIT
2461	default KUNIT_ALL_TESTS
2462	help
2463	  Enable this option to test the bitfield functions at boot.
2464
2465	  KUnit tests run during boot and output the results to the debug log
2466	  in TAP format (http://testanything.org/). Only useful for kernel devs
2467	  running the KUnit test harness, and not intended for inclusion into a
2468	  production build.
2469
2470	  For more information on KUnit and unit tests in general please refer
2471	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2472
2473	  If unsure, say N.
2474
2475config HASH_KUNIT_TEST
2476	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2477	depends on KUNIT
2478	default KUNIT_ALL_TESTS
2479	help
2480	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2481	  integer (<linux/hash.h>) hash functions on boot.
2482
2483	  KUnit tests run during boot and output the results to the debug log
2484	  in TAP format (https://testanything.org/). Only useful for kernel devs
2485	  running the KUnit test harness, and not intended for inclusion into a
2486	  production build.
2487
2488	  For more information on KUnit and unit tests in general please refer
2489	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2490
2491	  This is intended to help people writing architecture-specific
2492	  optimized versions. If unsure, say N.
2493
2494config RESOURCE_KUNIT_TEST
2495	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2496	depends on KUNIT
2497	default KUNIT_ALL_TESTS
2498	help
2499	  This builds the resource API unit test.
2500	  Tests the logic of API provided by resource.c and ioport.h.
2501	  For more information on KUnit and unit tests in general please refer
2502	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2503
2504	  If unsure, say N.
2505
2506config SYSCTL_KUNIT_TEST
2507	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2508	depends on KUNIT
2509	default KUNIT_ALL_TESTS
2510	help
2511	  This builds the proc sysctl unit test, which runs on boot.
2512	  Tests the API contract and implementation correctness of sysctl.
2513	  For more information on KUnit and unit tests in general please refer
2514	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2515
2516	  If unsure, say N.
2517
2518config LIST_KUNIT_TEST
2519	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2520	depends on KUNIT
2521	default KUNIT_ALL_TESTS
2522	help
2523	  This builds the linked list KUnit test suite.
2524	  It tests that the API and basic functionality of the list_head type
2525	  and associated macros.
2526
2527	  KUnit tests run during boot and output the results to the debug log
2528	  in TAP format (https://testanything.org/). Only useful for kernel devs
2529	  running the KUnit test harness, and not intended for inclusion into a
2530	  production build.
2531
2532	  For more information on KUnit and unit tests in general please refer
2533	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2534
2535	  If unsure, say N.
2536
2537config LINEAR_RANGES_TEST
2538	tristate "KUnit test for linear_ranges"
2539	depends on KUNIT
2540	select LINEAR_RANGES
2541	help
2542	  This builds the linear_ranges unit test, which runs on boot.
2543	  Tests the linear_ranges logic correctness.
2544	  For more information on KUnit and unit tests in general please refer
2545	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2546
2547	  If unsure, say N.
2548
2549config CMDLINE_KUNIT_TEST
2550	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2551	depends on KUNIT
2552	default KUNIT_ALL_TESTS
2553	help
2554	  This builds the cmdline API unit test.
2555	  Tests the logic of API provided by cmdline.c.
2556	  For more information on KUnit and unit tests in general please refer
2557	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2558
2559	  If unsure, say N.
2560
2561config BITS_TEST
2562	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2563	depends on KUNIT
2564	default KUNIT_ALL_TESTS
2565	help
2566	  This builds the bits unit test.
2567	  Tests the logic of macros defined in bits.h.
2568	  For more information on KUnit and unit tests in general please refer
2569	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2570
2571	  If unsure, say N.
2572
2573config SLUB_KUNIT_TEST
2574	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2575	depends on SLUB_DEBUG && KUNIT
2576	default KUNIT_ALL_TESTS
2577	help
2578	  This builds SLUB allocator unit test.
2579	  Tests SLUB cache debugging functionality.
2580	  For more information on KUnit and unit tests in general please refer
2581	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2582
2583	  If unsure, say N.
2584
2585config RATIONAL_KUNIT_TEST
2586	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2587	depends on KUNIT && RATIONAL
2588	default KUNIT_ALL_TESTS
2589	help
2590	  This builds the rational math unit test.
2591	  For more information on KUnit and unit tests in general please refer
2592	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2593
2594	  If unsure, say N.
2595
2596config MEMCPY_KUNIT_TEST
2597	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2598	depends on KUNIT
2599	default KUNIT_ALL_TESTS
2600	help
2601	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2602	  For more information on KUnit and unit tests in general please refer
2603	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2604
2605	  If unsure, say N.
2606
2607config IS_SIGNED_TYPE_KUNIT_TEST
2608	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2609	depends on KUNIT
2610	default KUNIT_ALL_TESTS
2611	help
2612	  Builds unit tests for the is_signed_type() macro.
2613
2614	  For more information on KUnit and unit tests in general please refer
2615	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2616
2617	  If unsure, say N.
2618
2619config OVERFLOW_KUNIT_TEST
2620	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2621	depends on KUNIT
2622	default KUNIT_ALL_TESTS
2623	help
2624	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2625	  related functions.
2626
2627	  For more information on KUnit and unit tests in general please refer
2628	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2629
2630	  If unsure, say N.
2631
2632config STACKINIT_KUNIT_TEST
2633	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2634	depends on KUNIT
2635	default KUNIT_ALL_TESTS
2636	help
2637	  Test if the kernel is zero-initializing stack variables and
2638	  padding. Coverage is controlled by compiler flags,
2639	  CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2640	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2641	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2642
2643config FORTIFY_KUNIT_TEST
2644	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2645	depends on KUNIT && FORTIFY_SOURCE
2646	default KUNIT_ALL_TESTS
2647	help
2648	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2649	  by the str*() and mem*() family of functions. For testing runtime
2650	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2651
2652config HW_BREAKPOINT_KUNIT_TEST
2653	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2654	depends on HAVE_HW_BREAKPOINT
2655	depends on KUNIT=y
2656	default KUNIT_ALL_TESTS
2657	help
2658	  Tests for hw_breakpoint constraints accounting.
2659
2660	  If unsure, say N.
2661
2662config STRSCPY_KUNIT_TEST
2663	tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2664	depends on KUNIT
2665	default KUNIT_ALL_TESTS
2666
2667config SIPHASH_KUNIT_TEST
2668	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2669	depends on KUNIT
2670	default KUNIT_ALL_TESTS
2671	help
2672	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2673	  functions on boot (or module load).
2674
2675	  This is intended to help people writing architecture-specific
2676	  optimized versions.  If unsure, say N.
2677
2678config TEST_UDELAY
2679	tristate "udelay test driver"
2680	help
2681	  This builds the "udelay_test" module that helps to make sure
2682	  that udelay() is working properly.
2683
2684	  If unsure, say N.
2685
2686config TEST_STATIC_KEYS
2687	tristate "Test static keys"
2688	depends on m
2689	help
2690	  Test the static key interfaces.
2691
2692	  If unsure, say N.
2693
2694config TEST_DYNAMIC_DEBUG
2695	tristate "Test DYNAMIC_DEBUG"
2696	depends on DYNAMIC_DEBUG
2697	help
2698	  This module registers a tracer callback to count enabled
2699	  pr_debugs in a 'do_debugging' function, then alters their
2700	  enablements, calls the function, and compares counts.
2701
2702	  If unsure, say N.
2703
2704config TEST_KMOD
2705	tristate "kmod stress tester"
2706	depends on m
2707	depends on NETDEVICES && NET_CORE && INET # for TUN
2708	depends on BLOCK
2709	depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2710	select TEST_LKM
2711	select XFS_FS
2712	select TUN
2713	select BTRFS_FS
2714	help
2715	  Test the kernel's module loading mechanism: kmod. kmod implements
2716	  support to load modules using the Linux kernel's usermode helper.
2717	  This test provides a series of tests against kmod.
2718
2719	  Although technically you can either build test_kmod as a module or
2720	  into the kernel we disallow building it into the kernel since
2721	  it stress tests request_module() and this will very likely cause
2722	  some issues by taking over precious threads available from other
2723	  module load requests, ultimately this could be fatal.
2724
2725	  To run tests run:
2726
2727	  tools/testing/selftests/kmod/kmod.sh --help
2728
2729	  If unsure, say N.
2730
2731config TEST_DEBUG_VIRTUAL
2732	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2733	depends on DEBUG_VIRTUAL
2734	help
2735	  Test the kernel's ability to detect incorrect calls to
2736	  virt_to_phys() done against the non-linear part of the
2737	  kernel's virtual address map.
2738
2739	  If unsure, say N.
2740
2741config TEST_MEMCAT_P
2742	tristate "Test memcat_p() helper function"
2743	help
2744	  Test the memcat_p() helper for correctly merging two
2745	  pointer arrays together.
2746
2747	  If unsure, say N.
2748
2749config TEST_LIVEPATCH
2750	tristate "Test livepatching"
2751	default n
2752	depends on DYNAMIC_DEBUG
2753	depends on LIVEPATCH
2754	depends on m
2755	help
2756	  Test kernel livepatching features for correctness.  The tests will
2757	  load test modules that will be livepatched in various scenarios.
2758
2759	  To run all the livepatching tests:
2760
2761	  make -C tools/testing/selftests TARGETS=livepatch run_tests
2762
2763	  Alternatively, individual tests may be invoked:
2764
2765	  tools/testing/selftests/livepatch/test-callbacks.sh
2766	  tools/testing/selftests/livepatch/test-livepatch.sh
2767	  tools/testing/selftests/livepatch/test-shadow-vars.sh
2768
2769	  If unsure, say N.
2770
2771config TEST_OBJAGG
2772	tristate "Perform selftest on object aggreration manager"
2773	default n
2774	depends on OBJAGG
2775	help
2776	  Enable this option to test object aggregation manager on boot
2777	  (or module load).
2778
2779config TEST_MEMINIT
2780	tristate "Test heap/page initialization"
2781	help
2782	  Test if the kernel is zero-initializing heap and page allocations.
2783	  This can be useful to test init_on_alloc and init_on_free features.
2784
2785	  If unsure, say N.
2786
2787config TEST_HMM
2788	tristate "Test HMM (Heterogeneous Memory Management)"
2789	depends on TRANSPARENT_HUGEPAGE
2790	depends on DEVICE_PRIVATE
2791	select HMM_MIRROR
2792	select MMU_NOTIFIER
2793	help
2794	  This is a pseudo device driver solely for testing HMM.
2795	  Say M here if you want to build the HMM test module.
2796	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2797
2798	  If unsure, say N.
2799
2800config TEST_FREE_PAGES
2801	tristate "Test freeing pages"
2802	help
2803	  Test that a memory leak does not occur due to a race between
2804	  freeing a block of pages and a speculative page reference.
2805	  Loading this module is safe if your kernel has the bug fixed.
2806	  If the bug is not fixed, it will leak gigabytes of memory and
2807	  probably OOM your system.
2808
2809config TEST_FPU
2810	tristate "Test floating point operations in kernel space"
2811	depends on X86 && !KCOV_INSTRUMENT_ALL
2812	help
2813	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2814	  which will trigger a sequence of floating point operations. This is used
2815	  for self-testing floating point control register setting in
2816	  kernel_fpu_begin().
2817
2818	  If unsure, say N.
2819
2820config TEST_CLOCKSOURCE_WATCHDOG
2821	tristate "Test clocksource watchdog in kernel space"
2822	depends on CLOCKSOURCE_WATCHDOG
2823	help
2824	  Enable this option to create a kernel module that will trigger
2825	  a test of the clocksource watchdog.  This module may be loaded
2826	  via modprobe or insmod in which case it will run upon being
2827	  loaded, or it may be built in, in which case it will run
2828	  shortly after boot.
2829
2830	  If unsure, say N.
2831
2832endif # RUNTIME_TESTING_MENU
2833
2834config ARCH_USE_MEMTEST
2835	bool
2836	help
2837	  An architecture should select this when it uses early_memtest()
2838	  during boot process.
2839
2840config MEMTEST
2841	bool "Memtest"
2842	depends on ARCH_USE_MEMTEST
2843	help
2844	  This option adds a kernel parameter 'memtest', which allows memtest
2845	  to be set and executed.
2846	        memtest=0, mean disabled; -- default
2847	        memtest=1, mean do 1 test pattern;
2848	        ...
2849	        memtest=17, mean do 17 test patterns.
2850	  If you are unsure how to answer this question, answer N.
2851
2852
2853
2854config HYPERV_TESTING
2855	bool "Microsoft Hyper-V driver testing"
2856	default n
2857	depends on HYPERV && DEBUG_FS
2858	help
2859	  Select this option to enable Hyper-V vmbus testing.
2860
2861endmenu # "Kernel Testing and Coverage"
2862
2863menu "Rust hacking"
2864
2865config RUST_DEBUG_ASSERTIONS
2866	bool "Debug assertions"
2867	depends on RUST
2868	help
2869	  Enables rustc's `-Cdebug-assertions` codegen option.
2870
2871	  This flag lets you turn `cfg(debug_assertions)` conditional
2872	  compilation on or off. This can be used to enable extra debugging
2873	  code in development but not in production. For example, it controls
2874	  the behavior of the standard library's `debug_assert!` macro.
2875
2876	  Note that this will apply to all Rust code, including `core`.
2877
2878	  If unsure, say N.
2879
2880config RUST_OVERFLOW_CHECKS
2881	bool "Overflow checks"
2882	default y
2883	depends on RUST
2884	help
2885	  Enables rustc's `-Coverflow-checks` codegen option.
2886
2887	  This flag allows you to control the behavior of runtime integer
2888	  overflow. When overflow-checks are enabled, a Rust panic will occur
2889	  on overflow.
2890
2891	  Note that this will apply to all Rust code, including `core`.
2892
2893	  If unsure, say Y.
2894
2895config RUST_BUILD_ASSERT_ALLOW
2896	bool "Allow unoptimized build-time assertions"
2897	depends on RUST
2898	help
2899	  Controls how are `build_error!` and `build_assert!` handled during build.
2900
2901	  If calls to them exist in the binary, it may indicate a violated invariant
2902	  or that the optimizer failed to verify the invariant during compilation.
2903
2904	  This should not happen, thus by default the build is aborted. However,
2905	  as an escape hatch, you can choose Y here to ignore them during build
2906	  and let the check be carried at runtime (with `panic!` being called if
2907	  the check fails).
2908
2909	  If unsure, say N.
2910
2911endmenu # "Rust"
2912
2913source "Documentation/Kconfig"
2914
2915endmenu # Kernel hacking
2916