xref: /openbmc/linux/lib/Kconfig.debug (revision 2a12187d)
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	default y
1250	help
1251	  If you say Y here then the kernel will use a debug variant of the
1252	  commonly used smp_processor_id() function and will print warnings
1253	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1254	  will detect preemption count underflows.
1255
1256menu "Lock Debugging (spinlocks, mutexes, etc...)"
1257
1258config LOCK_DEBUGGING_SUPPORT
1259	bool
1260	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1261	default y
1262
1263config PROVE_LOCKING
1264	bool "Lock debugging: prove locking correctness"
1265	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1266	select LOCKDEP
1267	select DEBUG_SPINLOCK
1268	select DEBUG_MUTEXES if !PREEMPT_RT
1269	select DEBUG_RT_MUTEXES if RT_MUTEXES
1270	select DEBUG_RWSEMS
1271	select DEBUG_WW_MUTEX_SLOWPATH
1272	select DEBUG_LOCK_ALLOC
1273	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1274	select TRACE_IRQFLAGS
1275	default n
1276	help
1277	 This feature enables the kernel to prove that all locking
1278	 that occurs in the kernel runtime is mathematically
1279	 correct: that under no circumstance could an arbitrary (and
1280	 not yet triggered) combination of observed locking
1281	 sequences (on an arbitrary number of CPUs, running an
1282	 arbitrary number of tasks and interrupt contexts) cause a
1283	 deadlock.
1284
1285	 In short, this feature enables the kernel to report locking
1286	 related deadlocks before they actually occur.
1287
1288	 The proof does not depend on how hard and complex a
1289	 deadlock scenario would be to trigger: how many
1290	 participant CPUs, tasks and irq-contexts would be needed
1291	 for it to trigger. The proof also does not depend on
1292	 timing: if a race and a resulting deadlock is possible
1293	 theoretically (no matter how unlikely the race scenario
1294	 is), it will be proven so and will immediately be
1295	 reported by the kernel (once the event is observed that
1296	 makes the deadlock theoretically possible).
1297
1298	 If a deadlock is impossible (i.e. the locking rules, as
1299	 observed by the kernel, are mathematically correct), the
1300	 kernel reports nothing.
1301
1302	 NOTE: this feature can also be enabled for rwlocks, mutexes
1303	 and rwsems - in which case all dependencies between these
1304	 different locking variants are observed and mapped too, and
1305	 the proof of observed correctness is also maintained for an
1306	 arbitrary combination of these separate locking variants.
1307
1308	 For more details, see Documentation/locking/lockdep-design.rst.
1309
1310config PROVE_RAW_LOCK_NESTING
1311	bool "Enable raw_spinlock - spinlock nesting checks"
1312	depends on PROVE_LOCKING
1313	default n
1314	help
1315	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1316	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1317	 not violated.
1318
1319	 NOTE: There are known nesting problems. So if you enable this
1320	 option expect lockdep splats until these problems have been fully
1321	 addressed which is work in progress. This config switch allows to
1322	 identify and analyze these problems. It will be removed and the
1323	 check permanently enabled once the main issues have been fixed.
1324
1325	 If unsure, select N.
1326
1327config LOCK_STAT
1328	bool "Lock usage statistics"
1329	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1330	select LOCKDEP
1331	select DEBUG_SPINLOCK
1332	select DEBUG_MUTEXES if !PREEMPT_RT
1333	select DEBUG_RT_MUTEXES if RT_MUTEXES
1334	select DEBUG_LOCK_ALLOC
1335	default n
1336	help
1337	 This feature enables tracking lock contention points
1338
1339	 For more details, see Documentation/locking/lockstat.rst
1340
1341	 This also enables lock events required by "perf lock",
1342	 subcommand of perf.
1343	 If you want to use "perf lock", you also need to turn on
1344	 CONFIG_EVENT_TRACING.
1345
1346	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1347	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1348
1349config DEBUG_RT_MUTEXES
1350	bool "RT Mutex debugging, deadlock detection"
1351	depends on DEBUG_KERNEL && RT_MUTEXES
1352	help
1353	 This allows rt mutex semantics violations and rt mutex related
1354	 deadlocks (lockups) to be detected and reported automatically.
1355
1356config DEBUG_SPINLOCK
1357	bool "Spinlock and rw-lock debugging: basic checks"
1358	depends on DEBUG_KERNEL
1359	select UNINLINE_SPIN_UNLOCK
1360	help
1361	  Say Y here and build SMP to catch missing spinlock initialization
1362	  and certain other kinds of spinlock errors commonly made.  This is
1363	  best used in conjunction with the NMI watchdog so that spinlock
1364	  deadlocks are also debuggable.
1365
1366config DEBUG_MUTEXES
1367	bool "Mutex debugging: basic checks"
1368	depends on DEBUG_KERNEL && !PREEMPT_RT
1369	help
1370	 This feature allows mutex semantics violations to be detected and
1371	 reported.
1372
1373config DEBUG_WW_MUTEX_SLOWPATH
1374	bool "Wait/wound mutex debugging: Slowpath testing"
1375	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1376	select DEBUG_LOCK_ALLOC
1377	select DEBUG_SPINLOCK
1378	select DEBUG_MUTEXES if !PREEMPT_RT
1379	select DEBUG_RT_MUTEXES if PREEMPT_RT
1380	help
1381	 This feature enables slowpath testing for w/w mutex users by
1382	 injecting additional -EDEADLK wound/backoff cases. Together with
1383	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1384	 will test all possible w/w mutex interface abuse with the
1385	 exception of simply not acquiring all the required locks.
1386	 Note that this feature can introduce significant overhead, so
1387	 it really should not be enabled in a production or distro kernel,
1388	 even a debug kernel.  If you are a driver writer, enable it.  If
1389	 you are a distro, do not.
1390
1391config DEBUG_RWSEMS
1392	bool "RW Semaphore debugging: basic checks"
1393	depends on DEBUG_KERNEL
1394	help
1395	  This debugging feature allows mismatched rw semaphore locks
1396	  and unlocks to be detected and reported.
1397
1398config DEBUG_LOCK_ALLOC
1399	bool "Lock debugging: detect incorrect freeing of live locks"
1400	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1401	select DEBUG_SPINLOCK
1402	select DEBUG_MUTEXES if !PREEMPT_RT
1403	select DEBUG_RT_MUTEXES if RT_MUTEXES
1404	select LOCKDEP
1405	help
1406	 This feature will check whether any held lock (spinlock, rwlock,
1407	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1408	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1409	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1410	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1411	 held during task exit.
1412
1413config LOCKDEP
1414	bool
1415	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1416	select STACKTRACE
1417	select KALLSYMS
1418	select KALLSYMS_ALL
1419
1420config LOCKDEP_SMALL
1421	bool
1422
1423config LOCKDEP_BITS
1424	int "Bitsize for MAX_LOCKDEP_ENTRIES"
1425	depends on LOCKDEP && !LOCKDEP_SMALL
1426	range 10 30
1427	default 15
1428	help
1429	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1430
1431config LOCKDEP_CHAINS_BITS
1432	int "Bitsize for MAX_LOCKDEP_CHAINS"
1433	depends on LOCKDEP && !LOCKDEP_SMALL
1434	range 10 30
1435	default 16
1436	help
1437	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1438
1439config LOCKDEP_STACK_TRACE_BITS
1440	int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1441	depends on LOCKDEP && !LOCKDEP_SMALL
1442	range 10 30
1443	default 19
1444	help
1445	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1446
1447config LOCKDEP_STACK_TRACE_HASH_BITS
1448	int "Bitsize for STACK_TRACE_HASH_SIZE"
1449	depends on LOCKDEP && !LOCKDEP_SMALL
1450	range 10 30
1451	default 14
1452	help
1453	  Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1454
1455config LOCKDEP_CIRCULAR_QUEUE_BITS
1456	int "Bitsize for elements in circular_queue struct"
1457	depends on LOCKDEP
1458	range 10 30
1459	default 12
1460	help
1461	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1462
1463config DEBUG_LOCKDEP
1464	bool "Lock dependency engine debugging"
1465	depends on DEBUG_KERNEL && LOCKDEP
1466	select DEBUG_IRQFLAGS
1467	help
1468	  If you say Y here, the lock dependency engine will do
1469	  additional runtime checks to debug itself, at the price
1470	  of more runtime overhead.
1471
1472config DEBUG_ATOMIC_SLEEP
1473	bool "Sleep inside atomic section checking"
1474	select PREEMPT_COUNT
1475	depends on DEBUG_KERNEL
1476	depends on !ARCH_NO_PREEMPT
1477	help
1478	  If you say Y here, various routines which may sleep will become very
1479	  noisy if they are called inside atomic sections: when a spinlock is
1480	  held, inside an rcu read side critical section, inside preempt disabled
1481	  sections, inside an interrupt, etc...
1482
1483config DEBUG_LOCKING_API_SELFTESTS
1484	bool "Locking API boot-time self-tests"
1485	depends on DEBUG_KERNEL
1486	help
1487	  Say Y here if you want the kernel to run a short self-test during
1488	  bootup. The self-test checks whether common types of locking bugs
1489	  are detected by debugging mechanisms or not. (if you disable
1490	  lock debugging then those bugs won't be detected of course.)
1491	  The following locking APIs are covered: spinlocks, rwlocks,
1492	  mutexes and rwsems.
1493
1494config LOCK_TORTURE_TEST
1495	tristate "torture tests for locking"
1496	depends on DEBUG_KERNEL
1497	select TORTURE_TEST
1498	help
1499	  This option provides a kernel module that runs torture tests
1500	  on kernel locking primitives.  The kernel module may be built
1501	  after the fact on the running kernel to be tested, if desired.
1502
1503	  Say Y here if you want kernel locking-primitive torture tests
1504	  to be built into the kernel.
1505	  Say M if you want these torture tests to build as a module.
1506	  Say N if you are unsure.
1507
1508config WW_MUTEX_SELFTEST
1509	tristate "Wait/wound mutex selftests"
1510	help
1511	  This option provides a kernel module that runs tests on the
1512	  on the struct ww_mutex locking API.
1513
1514	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1515	  with this test harness.
1516
1517	  Say M if you want these self tests to build as a module.
1518	  Say N if you are unsure.
1519
1520config SCF_TORTURE_TEST
1521	tristate "torture tests for smp_call_function*()"
1522	depends on DEBUG_KERNEL
1523	select TORTURE_TEST
1524	help
1525	  This option provides a kernel module that runs torture tests
1526	  on the smp_call_function() family of primitives.  The kernel
1527	  module may be built after the fact on the running kernel to
1528	  be tested, if desired.
1529
1530config CSD_LOCK_WAIT_DEBUG
1531	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1532	depends on DEBUG_KERNEL
1533	depends on 64BIT
1534	default n
1535	help
1536	  This option enables debug prints when CPUs are slow to respond
1537	  to the smp_call_function*() IPI wrappers.  These debug prints
1538	  include the IPI handler function currently executing (if any)
1539	  and relevant stack traces.
1540
1541endmenu # lock debugging
1542
1543config TRACE_IRQFLAGS
1544	depends on TRACE_IRQFLAGS_SUPPORT
1545	bool
1546	help
1547	  Enables hooks to interrupt enabling and disabling for
1548	  either tracing or lock debugging.
1549
1550config TRACE_IRQFLAGS_NMI
1551	def_bool y
1552	depends on TRACE_IRQFLAGS
1553	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1554
1555config DEBUG_IRQFLAGS
1556	bool "Debug IRQ flag manipulation"
1557	help
1558	  Enables checks for potentially unsafe enabling or disabling of
1559	  interrupts, such as calling raw_local_irq_restore() when interrupts
1560	  are enabled.
1561
1562config STACKTRACE
1563	bool "Stack backtrace support"
1564	depends on STACKTRACE_SUPPORT
1565	help
1566	  This option causes the kernel to create a /proc/pid/stack for
1567	  every process, showing its current stack trace.
1568	  It is also used by various kernel debugging features that require
1569	  stack trace generation.
1570
1571config WARN_ALL_UNSEEDED_RANDOM
1572	bool "Warn for all uses of unseeded randomness"
1573	default n
1574	help
1575	  Some parts of the kernel contain bugs relating to their use of
1576	  cryptographically secure random numbers before it's actually possible
1577	  to generate those numbers securely. This setting ensures that these
1578	  flaws don't go unnoticed, by enabling a message, should this ever
1579	  occur. This will allow people with obscure setups to know when things
1580	  are going wrong, so that they might contact developers about fixing
1581	  it.
1582
1583	  Unfortunately, on some models of some architectures getting
1584	  a fully seeded CRNG is extremely difficult, and so this can
1585	  result in dmesg getting spammed for a surprisingly long
1586	  time.  This is really bad from a security perspective, and
1587	  so architecture maintainers really need to do what they can
1588	  to get the CRNG seeded sooner after the system is booted.
1589	  However, since users cannot do anything actionable to
1590	  address this, by default this option is disabled.
1591
1592	  Say Y here if you want to receive warnings for all uses of
1593	  unseeded randomness.  This will be of use primarily for
1594	  those developers interested in improving the security of
1595	  Linux kernels running on their architecture (or
1596	  subarchitecture).
1597
1598config DEBUG_KOBJECT
1599	bool "kobject debugging"
1600	depends on DEBUG_KERNEL
1601	help
1602	  If you say Y here, some extra kobject debugging messages will be sent
1603	  to the syslog.
1604
1605config DEBUG_KOBJECT_RELEASE
1606	bool "kobject release debugging"
1607	depends on DEBUG_OBJECTS_TIMERS
1608	help
1609	  kobjects are reference counted objects.  This means that their
1610	  last reference count put is not predictable, and the kobject can
1611	  live on past the point at which a driver decides to drop its
1612	  initial reference to the kobject gained on allocation.  An
1613	  example of this would be a struct device which has just been
1614	  unregistered.
1615
1616	  However, some buggy drivers assume that after such an operation,
1617	  the memory backing the kobject can be immediately freed.  This
1618	  goes completely against the principles of a refcounted object.
1619
1620	  If you say Y here, the kernel will delay the release of kobjects
1621	  on the last reference count to improve the visibility of this
1622	  kind of kobject release bug.
1623
1624config HAVE_DEBUG_BUGVERBOSE
1625	bool
1626
1627menu "Debug kernel data structures"
1628
1629config DEBUG_LIST
1630	bool "Debug linked list manipulation"
1631	depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1632	help
1633	  Enable this to turn on extended checks in the linked-list
1634	  walking routines.
1635
1636	  If unsure, say N.
1637
1638config DEBUG_PLIST
1639	bool "Debug priority linked list manipulation"
1640	depends on DEBUG_KERNEL
1641	help
1642	  Enable this to turn on extended checks in the priority-ordered
1643	  linked-list (plist) walking routines.  This checks the entire
1644	  list multiple times during each manipulation.
1645
1646	  If unsure, say N.
1647
1648config DEBUG_SG
1649	bool "Debug SG table operations"
1650	depends on DEBUG_KERNEL
1651	help
1652	  Enable this to turn on checks on scatter-gather tables. This can
1653	  help find problems with drivers that do not properly initialize
1654	  their sg tables.
1655
1656	  If unsure, say N.
1657
1658config DEBUG_NOTIFIERS
1659	bool "Debug notifier call chains"
1660	depends on DEBUG_KERNEL
1661	help
1662	  Enable this to turn on sanity checking for notifier call chains.
1663	  This is most useful for kernel developers to make sure that
1664	  modules properly unregister themselves from notifier chains.
1665	  This is a relatively cheap check but if you care about maximum
1666	  performance, say N.
1667
1668config BUG_ON_DATA_CORRUPTION
1669	bool "Trigger a BUG when data corruption is detected"
1670	select DEBUG_LIST
1671	help
1672	  Select this option if the kernel should BUG when it encounters
1673	  data corruption in kernel memory structures when they get checked
1674	  for validity.
1675
1676	  If unsure, say N.
1677
1678config DEBUG_MAPLE_TREE
1679	bool "Debug maple trees"
1680	depends on DEBUG_KERNEL
1681	help
1682	  Enable maple tree debugging information and extra validations.
1683
1684	  If unsure, say N.
1685
1686endmenu
1687
1688config DEBUG_CREDENTIALS
1689	bool "Debug credential management"
1690	depends on DEBUG_KERNEL
1691	help
1692	  Enable this to turn on some debug checking for credential
1693	  management.  The additional code keeps track of the number of
1694	  pointers from task_structs to any given cred struct, and checks to
1695	  see that this number never exceeds the usage count of the cred
1696	  struct.
1697
1698	  Furthermore, if SELinux is enabled, this also checks that the
1699	  security pointer in the cred struct is never seen to be invalid.
1700
1701	  If unsure, say N.
1702
1703source "kernel/rcu/Kconfig.debug"
1704
1705config DEBUG_WQ_FORCE_RR_CPU
1706	bool "Force round-robin CPU selection for unbound work items"
1707	depends on DEBUG_KERNEL
1708	default n
1709	help
1710	  Workqueue used to implicitly guarantee that work items queued
1711	  without explicit CPU specified are put on the local CPU.  This
1712	  guarantee is no longer true and while local CPU is still
1713	  preferred work items may be put on foreign CPUs.  Kernel
1714	  parameter "workqueue.debug_force_rr_cpu" is added to force
1715	  round-robin CPU selection to flush out usages which depend on the
1716	  now broken guarantee.  This config option enables the debug
1717	  feature by default.  When enabled, memory and cache locality will
1718	  be impacted.
1719
1720config CPU_HOTPLUG_STATE_CONTROL
1721	bool "Enable CPU hotplug state control"
1722	depends on DEBUG_KERNEL
1723	depends on HOTPLUG_CPU
1724	default n
1725	help
1726	  Allows to write steps between "offline" and "online" to the CPUs
1727	  sysfs target file so states can be stepped granular. This is a debug
1728	  option for now as the hotplug machinery cannot be stopped and
1729	  restarted at arbitrary points yet.
1730
1731	  Say N if your are unsure.
1732
1733config LATENCYTOP
1734	bool "Latency measuring infrastructure"
1735	depends on DEBUG_KERNEL
1736	depends on STACKTRACE_SUPPORT
1737	depends on PROC_FS
1738	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1739	select KALLSYMS
1740	select KALLSYMS_ALL
1741	select STACKTRACE
1742	select SCHEDSTATS
1743	help
1744	  Enable this option if you want to use the LatencyTOP tool
1745	  to find out which userspace is blocking on what kernel operations.
1746
1747config DEBUG_CGROUP_REF
1748	bool "Disable inlining of cgroup css reference count functions"
1749	depends on DEBUG_KERNEL
1750	depends on CGROUPS
1751	depends on KPROBES
1752	default n
1753	help
1754	  Force cgroup css reference count functions to not be inlined so
1755	  that they can be kprobed for debugging.
1756
1757source "kernel/trace/Kconfig"
1758
1759config PROVIDE_OHCI1394_DMA_INIT
1760	bool "Remote debugging over FireWire early on boot"
1761	depends on PCI && X86
1762	help
1763	  If you want to debug problems which hang or crash the kernel early
1764	  on boot and the crashing machine has a FireWire port, you can use
1765	  this feature to remotely access the memory of the crashed machine
1766	  over FireWire. This employs remote DMA as part of the OHCI1394
1767	  specification which is now the standard for FireWire controllers.
1768
1769	  With remote DMA, you can monitor the printk buffer remotely using
1770	  firescope and access all memory below 4GB using fireproxy from gdb.
1771	  Even controlling a kernel debugger is possible using remote DMA.
1772
1773	  Usage:
1774
1775	  If ohci1394_dma=early is used as boot parameter, it will initialize
1776	  all OHCI1394 controllers which are found in the PCI config space.
1777
1778	  As all changes to the FireWire bus such as enabling and disabling
1779	  devices cause a bus reset and thereby disable remote DMA for all
1780	  devices, be sure to have the cable plugged and FireWire enabled on
1781	  the debugging host before booting the debug target for debugging.
1782
1783	  This code (~1k) is freed after boot. By then, the firewire stack
1784	  in charge of the OHCI-1394 controllers should be used instead.
1785
1786	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1787
1788source "samples/Kconfig"
1789
1790config ARCH_HAS_DEVMEM_IS_ALLOWED
1791	bool
1792
1793config STRICT_DEVMEM
1794	bool "Filter access to /dev/mem"
1795	depends on MMU && DEVMEM
1796	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1797	default y if PPC || X86 || ARM64
1798	help
1799	  If this option is disabled, you allow userspace (root) access to all
1800	  of memory, including kernel and userspace memory. Accidental
1801	  access to this is obviously disastrous, but specific access can
1802	  be used by people debugging the kernel. Note that with PAT support
1803	  enabled, even in this case there are restrictions on /dev/mem
1804	  use due to the cache aliasing requirements.
1805
1806	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1807	  file only allows userspace access to PCI space and the BIOS code and
1808	  data regions.  This is sufficient for dosemu and X and all common
1809	  users of /dev/mem.
1810
1811	  If in doubt, say Y.
1812
1813config IO_STRICT_DEVMEM
1814	bool "Filter I/O access to /dev/mem"
1815	depends on STRICT_DEVMEM
1816	help
1817	  If this option is disabled, you allow userspace (root) access to all
1818	  io-memory regardless of whether a driver is actively using that
1819	  range.  Accidental access to this is obviously disastrous, but
1820	  specific access can be used by people debugging kernel drivers.
1821
1822	  If this option is switched on, the /dev/mem file only allows
1823	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1824	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1825	  if the driver using a given range cannot be disabled.
1826
1827	  If in doubt, say Y.
1828
1829menu "$(SRCARCH) Debugging"
1830
1831source "arch/$(SRCARCH)/Kconfig.debug"
1832
1833endmenu
1834
1835menu "Kernel Testing and Coverage"
1836
1837source "lib/kunit/Kconfig"
1838
1839config NOTIFIER_ERROR_INJECTION
1840	tristate "Notifier error injection"
1841	depends on DEBUG_KERNEL
1842	select DEBUG_FS
1843	help
1844	  This option provides the ability to inject artificial errors to
1845	  specified notifier chain callbacks. It is useful to test the error
1846	  handling of notifier call chain failures.
1847
1848	  Say N if unsure.
1849
1850config PM_NOTIFIER_ERROR_INJECT
1851	tristate "PM notifier error injection module"
1852	depends on PM && NOTIFIER_ERROR_INJECTION
1853	default m if PM_DEBUG
1854	help
1855	  This option provides the ability to inject artificial errors to
1856	  PM notifier chain callbacks.  It is controlled through debugfs
1857	  interface /sys/kernel/debug/notifier-error-inject/pm
1858
1859	  If the notifier call chain should be failed with some events
1860	  notified, write the error code to "actions/<notifier event>/error".
1861
1862	  Example: Inject PM suspend error (-12 = -ENOMEM)
1863
1864	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1865	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1866	  # echo mem > /sys/power/state
1867	  bash: echo: write error: Cannot allocate memory
1868
1869	  To compile this code as a module, choose M here: the module will
1870	  be called pm-notifier-error-inject.
1871
1872	  If unsure, say N.
1873
1874config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1875	tristate "OF reconfig notifier error injection module"
1876	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1877	help
1878	  This option provides the ability to inject artificial errors to
1879	  OF reconfig notifier chain callbacks.  It is controlled
1880	  through debugfs interface under
1881	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1882
1883	  If the notifier call chain should be failed with some events
1884	  notified, write the error code to "actions/<notifier event>/error".
1885
1886	  To compile this code as a module, choose M here: the module will
1887	  be called of-reconfig-notifier-error-inject.
1888
1889	  If unsure, say N.
1890
1891config NETDEV_NOTIFIER_ERROR_INJECT
1892	tristate "Netdev notifier error injection module"
1893	depends on NET && NOTIFIER_ERROR_INJECTION
1894	help
1895	  This option provides the ability to inject artificial errors to
1896	  netdevice notifier chain callbacks.  It is controlled through debugfs
1897	  interface /sys/kernel/debug/notifier-error-inject/netdev
1898
1899	  If the notifier call chain should be failed with some events
1900	  notified, write the error code to "actions/<notifier event>/error".
1901
1902	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
1903
1904	  # cd /sys/kernel/debug/notifier-error-inject/netdev
1905	  # echo -22 > actions/NETDEV_CHANGEMTU/error
1906	  # ip link set eth0 mtu 1024
1907	  RTNETLINK answers: Invalid argument
1908
1909	  To compile this code as a module, choose M here: the module will
1910	  be called netdev-notifier-error-inject.
1911
1912	  If unsure, say N.
1913
1914config FUNCTION_ERROR_INJECTION
1915	bool "Fault-injections of functions"
1916	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1917	help
1918	  Add fault injections into various functions that are annotated with
1919	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1920	  value of theses functions. This is useful to test error paths of code.
1921
1922	  If unsure, say N
1923
1924config FAULT_INJECTION
1925	bool "Fault-injection framework"
1926	depends on DEBUG_KERNEL
1927	help
1928	  Provide fault-injection framework.
1929	  For more details, see Documentation/fault-injection/.
1930
1931config FAILSLAB
1932	bool "Fault-injection capability for kmalloc"
1933	depends on FAULT_INJECTION
1934	depends on SLAB || SLUB
1935	help
1936	  Provide fault-injection capability for kmalloc.
1937
1938config FAIL_PAGE_ALLOC
1939	bool "Fault-injection capability for alloc_pages()"
1940	depends on FAULT_INJECTION
1941	help
1942	  Provide fault-injection capability for alloc_pages().
1943
1944config FAULT_INJECTION_USERCOPY
1945	bool "Fault injection capability for usercopy functions"
1946	depends on FAULT_INJECTION
1947	help
1948	  Provides fault-injection capability to inject failures
1949	  in usercopy functions (copy_from_user(), get_user(), ...).
1950
1951config FAIL_MAKE_REQUEST
1952	bool "Fault-injection capability for disk IO"
1953	depends on FAULT_INJECTION && BLOCK
1954	help
1955	  Provide fault-injection capability for disk IO.
1956
1957config FAIL_IO_TIMEOUT
1958	bool "Fault-injection capability for faking disk interrupts"
1959	depends on FAULT_INJECTION && BLOCK
1960	help
1961	  Provide fault-injection capability on end IO handling. This
1962	  will make the block layer "forget" an interrupt as configured,
1963	  thus exercising the error handling.
1964
1965	  Only works with drivers that use the generic timeout handling,
1966	  for others it won't do anything.
1967
1968config FAIL_FUTEX
1969	bool "Fault-injection capability for futexes"
1970	select DEBUG_FS
1971	depends on FAULT_INJECTION && FUTEX
1972	help
1973	  Provide fault-injection capability for futexes.
1974
1975config FAULT_INJECTION_DEBUG_FS
1976	bool "Debugfs entries for fault-injection capabilities"
1977	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1978	help
1979	  Enable configuration of fault-injection capabilities via debugfs.
1980
1981config FAIL_FUNCTION
1982	bool "Fault-injection capability for functions"
1983	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1984	help
1985	  Provide function-based fault-injection capability.
1986	  This will allow you to override a specific function with a return
1987	  with given return value. As a result, function caller will see
1988	  an error value and have to handle it. This is useful to test the
1989	  error handling in various subsystems.
1990
1991config FAIL_MMC_REQUEST
1992	bool "Fault-injection capability for MMC IO"
1993	depends on FAULT_INJECTION_DEBUG_FS && MMC
1994	help
1995	  Provide fault-injection capability for MMC IO.
1996	  This will make the mmc core return data errors. This is
1997	  useful to test the error handling in the mmc block device
1998	  and to test how the mmc host driver handles retries from
1999	  the block device.
2000
2001config FAIL_SUNRPC
2002	bool "Fault-injection capability for SunRPC"
2003	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2004	help
2005	  Provide fault-injection capability for SunRPC and
2006	  its consumers.
2007
2008config FAULT_INJECTION_STACKTRACE_FILTER
2009	bool "stacktrace filter for fault-injection capabilities"
2010	depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2011	select STACKTRACE
2012	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2013	help
2014	  Provide stacktrace filter for fault-injection capabilities
2015
2016config ARCH_HAS_KCOV
2017	bool
2018	help
2019	  An architecture should select this when it can successfully
2020	  build and run with CONFIG_KCOV. This typically requires
2021	  disabling instrumentation for some early boot code.
2022
2023config CC_HAS_SANCOV_TRACE_PC
2024	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2025
2026
2027config KCOV
2028	bool "Code coverage for fuzzing"
2029	depends on ARCH_HAS_KCOV
2030	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2031	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2032		   GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2033	select DEBUG_FS
2034	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2035	select OBJTOOL if HAVE_NOINSTR_HACK
2036	help
2037	  KCOV exposes kernel code coverage information in a form suitable
2038	  for coverage-guided fuzzing (randomized testing).
2039
2040	  If RANDOMIZE_BASE is enabled, PC values will not be stable across
2041	  different machines and across reboots. If you need stable PC values,
2042	  disable RANDOMIZE_BASE.
2043
2044	  For more details, see Documentation/dev-tools/kcov.rst.
2045
2046config KCOV_ENABLE_COMPARISONS
2047	bool "Enable comparison operands collection by KCOV"
2048	depends on KCOV
2049	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2050	help
2051	  KCOV also exposes operands of every comparison in the instrumented
2052	  code along with operand sizes and PCs of the comparison instructions.
2053	  These operands can be used by fuzzing engines to improve the quality
2054	  of fuzzing coverage.
2055
2056config KCOV_INSTRUMENT_ALL
2057	bool "Instrument all code by default"
2058	depends on KCOV
2059	default y
2060	help
2061	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2062	  then you will want to instrument the whole kernel and you should
2063	  say y here. If you are doing more targeted fuzzing (like e.g.
2064	  filesystem fuzzing with AFL) then you will want to enable coverage
2065	  for more specific subsets of files, and should say n here.
2066
2067config KCOV_IRQ_AREA_SIZE
2068	hex "Size of interrupt coverage collection area in words"
2069	depends on KCOV
2070	default 0x40000
2071	help
2072	  KCOV uses preallocated per-cpu areas to collect coverage from
2073	  soft interrupts. This specifies the size of those areas in the
2074	  number of unsigned long words.
2075
2076menuconfig RUNTIME_TESTING_MENU
2077	bool "Runtime Testing"
2078	def_bool y
2079
2080if RUNTIME_TESTING_MENU
2081
2082config LKDTM
2083	tristate "Linux Kernel Dump Test Tool Module"
2084	depends on DEBUG_FS
2085	help
2086	This module enables testing of the different dumping mechanisms by
2087	inducing system failures at predefined crash points.
2088	If you don't need it: say N
2089	Choose M here to compile this code as a module. The module will be
2090	called lkdtm.
2091
2092	Documentation on how to use the module can be found in
2093	Documentation/fault-injection/provoke-crashes.rst
2094
2095config CPUMASK_KUNIT_TEST
2096	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2097	depends on KUNIT
2098	default KUNIT_ALL_TESTS
2099	help
2100	  Enable to turn on cpumask tests, running at boot or module load time.
2101
2102	  For more information on KUnit and unit tests in general, please refer
2103	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2104
2105	  If unsure, say N.
2106
2107config TEST_LIST_SORT
2108	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2109	depends on KUNIT
2110	default KUNIT_ALL_TESTS
2111	help
2112	  Enable this to turn on 'list_sort()' function test. This test is
2113	  executed only once during system boot (so affects only boot time),
2114	  or at module load time.
2115
2116	  If unsure, say N.
2117
2118config TEST_MIN_HEAP
2119	tristate "Min heap test"
2120	depends on DEBUG_KERNEL || m
2121	help
2122	  Enable this to turn on min heap function tests. This test is
2123	  executed only once during system boot (so affects only boot time),
2124	  or at module load time.
2125
2126	  If unsure, say N.
2127
2128config TEST_SORT
2129	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2130	depends on KUNIT
2131	default KUNIT_ALL_TESTS
2132	help
2133	  This option enables the self-test function of 'sort()' at boot,
2134	  or at module load time.
2135
2136	  If unsure, say N.
2137
2138config TEST_DIV64
2139	tristate "64bit/32bit division and modulo test"
2140	depends on DEBUG_KERNEL || m
2141	help
2142	  Enable this to turn on 'do_div()' function test. This test is
2143	  executed only once during system boot (so affects only boot time),
2144	  or at module load time.
2145
2146	  If unsure, say N.
2147
2148config KPROBES_SANITY_TEST
2149	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2150	depends on DEBUG_KERNEL
2151	depends on KPROBES
2152	depends on KUNIT
2153	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2154	default KUNIT_ALL_TESTS
2155	help
2156	  This option provides for testing basic kprobes functionality on
2157	  boot. Samples of kprobe and kretprobe are inserted and
2158	  verified for functionality.
2159
2160	  Say N if you are unsure.
2161
2162config FPROBE_SANITY_TEST
2163	bool "Self test for fprobe"
2164	depends on DEBUG_KERNEL
2165	depends on FPROBE
2166	depends on KUNIT=y
2167	help
2168	  This option will enable testing the fprobe when the system boot.
2169	  A series of tests are made to verify that the fprobe is functioning
2170	  properly.
2171
2172	  Say N if you are unsure.
2173
2174config BACKTRACE_SELF_TEST
2175	tristate "Self test for the backtrace code"
2176	depends on DEBUG_KERNEL
2177	help
2178	  This option provides a kernel module that can be used to test
2179	  the kernel stack backtrace code. This option is not useful
2180	  for distributions or general kernels, but only for kernel
2181	  developers working on architecture code.
2182
2183	  Note that if you want to also test saved backtraces, you will
2184	  have to enable STACKTRACE as well.
2185
2186	  Say N if you are unsure.
2187
2188config TEST_REF_TRACKER
2189	tristate "Self test for reference tracker"
2190	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2191	select REF_TRACKER
2192	help
2193	  This option provides a kernel module performing tests
2194	  using reference tracker infrastructure.
2195
2196	  Say N if you are unsure.
2197
2198config RBTREE_TEST
2199	tristate "Red-Black tree test"
2200	depends on DEBUG_KERNEL
2201	help
2202	  A benchmark measuring the performance of the rbtree library.
2203	  Also includes rbtree invariant checks.
2204
2205config REED_SOLOMON_TEST
2206	tristate "Reed-Solomon library test"
2207	depends on DEBUG_KERNEL || m
2208	select REED_SOLOMON
2209	select REED_SOLOMON_ENC16
2210	select REED_SOLOMON_DEC16
2211	help
2212	  This option enables the self-test function of rslib at boot,
2213	  or at module load time.
2214
2215	  If unsure, say N.
2216
2217config INTERVAL_TREE_TEST
2218	tristate "Interval tree test"
2219	depends on DEBUG_KERNEL
2220	select INTERVAL_TREE
2221	help
2222	  A benchmark measuring the performance of the interval tree library
2223
2224config PERCPU_TEST
2225	tristate "Per cpu operations test"
2226	depends on m && DEBUG_KERNEL
2227	help
2228	  Enable this option to build test module which validates per-cpu
2229	  operations.
2230
2231	  If unsure, say N.
2232
2233config ATOMIC64_SELFTEST
2234	tristate "Perform an atomic64_t self-test"
2235	help
2236	  Enable this option to test the atomic64_t functions at boot or
2237	  at module load time.
2238
2239	  If unsure, say N.
2240
2241config ASYNC_RAID6_TEST
2242	tristate "Self test for hardware accelerated raid6 recovery"
2243	depends on ASYNC_RAID6_RECOV
2244	select ASYNC_MEMCPY
2245	help
2246	  This is a one-shot self test that permutes through the
2247	  recovery of all the possible two disk failure scenarios for a
2248	  N-disk array.  Recovery is performed with the asynchronous
2249	  raid6 recovery routines, and will optionally use an offload
2250	  engine if one is available.
2251
2252	  If unsure, say N.
2253
2254config TEST_HEXDUMP
2255	tristate "Test functions located in the hexdump module at runtime"
2256
2257config STRING_SELFTEST
2258	tristate "Test string functions at runtime"
2259
2260config TEST_STRING_HELPERS
2261	tristate "Test functions located in the string_helpers module at runtime"
2262
2263config TEST_KSTRTOX
2264	tristate "Test kstrto*() family of functions at runtime"
2265
2266config TEST_PRINTF
2267	tristate "Test printf() family of functions at runtime"
2268
2269config TEST_SCANF
2270	tristate "Test scanf() family of functions at runtime"
2271
2272config TEST_BITMAP
2273	tristate "Test bitmap_*() family of functions at runtime"
2274	help
2275	  Enable this option to test the bitmap functions at boot.
2276
2277	  If unsure, say N.
2278
2279config TEST_UUID
2280	tristate "Test functions located in the uuid module at runtime"
2281
2282config TEST_XARRAY
2283	tristate "Test the XArray code at runtime"
2284
2285config TEST_MAPLE_TREE
2286	depends on DEBUG_KERNEL
2287	select DEBUG_MAPLE_TREE
2288	tristate "Test the Maple Tree code at runtime"
2289
2290config TEST_RHASHTABLE
2291	tristate "Perform selftest on resizable hash table"
2292	help
2293	  Enable this option to test the rhashtable functions at boot.
2294
2295	  If unsure, say N.
2296
2297config TEST_IDA
2298	tristate "Perform selftest on IDA functions"
2299
2300config TEST_PARMAN
2301	tristate "Perform selftest on priority array manager"
2302	depends on PARMAN
2303	help
2304	  Enable this option to test priority array manager on boot
2305	  (or module load).
2306
2307	  If unsure, say N.
2308
2309config TEST_IRQ_TIMINGS
2310	bool "IRQ timings selftest"
2311	depends on IRQ_TIMINGS
2312	help
2313	  Enable this option to test the irq timings code on boot.
2314
2315	  If unsure, say N.
2316
2317config TEST_LKM
2318	tristate "Test module loading with 'hello world' module"
2319	depends on m
2320	help
2321	  This builds the "test_module" module that emits "Hello, world"
2322	  on printk when loaded. It is designed to be used for basic
2323	  evaluation of the module loading subsystem (for example when
2324	  validating module verification). It lacks any extra dependencies,
2325	  and will not normally be loaded by the system unless explicitly
2326	  requested by name.
2327
2328	  If unsure, say N.
2329
2330config TEST_BITOPS
2331	tristate "Test module for compilation of bitops operations"
2332	depends on m
2333	help
2334	  This builds the "test_bitops" module that is much like the
2335	  TEST_LKM module except that it does a basic exercise of the
2336	  set/clear_bit macros and get_count_order/long to make sure there are
2337	  no compiler warnings from C=1 sparse checker or -Wextra
2338	  compilations. It has no dependencies and doesn't run or load unless
2339	  explicitly requested by name.  for example: modprobe test_bitops.
2340
2341	  If unsure, say N.
2342
2343config TEST_VMALLOC
2344	tristate "Test module for stress/performance analysis of vmalloc allocator"
2345	default n
2346       depends on MMU
2347	depends on m
2348	help
2349	  This builds the "test_vmalloc" module that should be used for
2350	  stress and performance analysis. So, any new change for vmalloc
2351	  subsystem can be evaluated from performance and stability point
2352	  of view.
2353
2354	  If unsure, say N.
2355
2356config TEST_USER_COPY
2357	tristate "Test user/kernel boundary protections"
2358	depends on m
2359	help
2360	  This builds the "test_user_copy" module that runs sanity checks
2361	  on the copy_to/from_user infrastructure, making sure basic
2362	  user/kernel boundary testing is working. If it fails to load,
2363	  a regression has been detected in the user/kernel memory boundary
2364	  protections.
2365
2366	  If unsure, say N.
2367
2368config TEST_BPF
2369	tristate "Test BPF filter functionality"
2370	depends on m && NET
2371	help
2372	  This builds the "test_bpf" module that runs various test vectors
2373	  against the BPF interpreter or BPF JIT compiler depending on the
2374	  current setting. This is in particular useful for BPF JIT compiler
2375	  development, but also to run regression tests against changes in
2376	  the interpreter code. It also enables test stubs for eBPF maps and
2377	  verifier used by user space verifier testsuite.
2378
2379	  If unsure, say N.
2380
2381config TEST_BLACKHOLE_DEV
2382	tristate "Test blackhole netdev functionality"
2383	depends on m && NET
2384	help
2385	  This builds the "test_blackhole_dev" module that validates the
2386	  data path through this blackhole netdev.
2387
2388	  If unsure, say N.
2389
2390config FIND_BIT_BENCHMARK
2391	tristate "Test find_bit functions"
2392	help
2393	  This builds the "test_find_bit" module that measure find_*_bit()
2394	  functions performance.
2395
2396	  If unsure, say N.
2397
2398config TEST_FIRMWARE
2399	tristate "Test firmware loading via userspace interface"
2400	depends on FW_LOADER
2401	help
2402	  This builds the "test_firmware" module that creates a userspace
2403	  interface for testing firmware loading. This can be used to
2404	  control the triggering of firmware loading without needing an
2405	  actual firmware-using device. The contents can be rechecked by
2406	  userspace.
2407
2408	  If unsure, say N.
2409
2410config TEST_SYSCTL
2411	tristate "sysctl test driver"
2412	depends on PROC_SYSCTL
2413	help
2414	  This builds the "test_sysctl" module. This driver enables to test the
2415	  proc sysctl interfaces available to drivers safely without affecting
2416	  production knobs which might alter system functionality.
2417
2418	  If unsure, say N.
2419
2420config BITFIELD_KUNIT
2421	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2422	depends on KUNIT
2423	default KUNIT_ALL_TESTS
2424	help
2425	  Enable this option to test the bitfield functions at boot.
2426
2427	  KUnit tests run during boot and output the results to the debug log
2428	  in TAP format (http://testanything.org/). Only useful for kernel devs
2429	  running the KUnit test harness, and not intended for inclusion into a
2430	  production build.
2431
2432	  For more information on KUnit and unit tests in general please refer
2433	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2434
2435	  If unsure, say N.
2436
2437config HASH_KUNIT_TEST
2438	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2439	depends on KUNIT
2440	default KUNIT_ALL_TESTS
2441	help
2442	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2443	  integer (<linux/hash.h>) hash functions on boot.
2444
2445	  KUnit tests run during boot and output the results to the debug log
2446	  in TAP format (https://testanything.org/). Only useful for kernel devs
2447	  running the KUnit test harness, and not intended for inclusion into a
2448	  production build.
2449
2450	  For more information on KUnit and unit tests in general please refer
2451	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2452
2453	  This is intended to help people writing architecture-specific
2454	  optimized versions. If unsure, say N.
2455
2456config RESOURCE_KUNIT_TEST
2457	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2458	depends on KUNIT
2459	default KUNIT_ALL_TESTS
2460	help
2461	  This builds the resource API unit test.
2462	  Tests the logic of API provided by resource.c and ioport.h.
2463	  For more information on KUnit and unit tests in general please refer
2464	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2465
2466	  If unsure, say N.
2467
2468config SYSCTL_KUNIT_TEST
2469	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2470	depends on KUNIT
2471	default KUNIT_ALL_TESTS
2472	help
2473	  This builds the proc sysctl unit test, which runs on boot.
2474	  Tests the API contract and implementation correctness of sysctl.
2475	  For more information on KUnit and unit tests in general please refer
2476	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2477
2478	  If unsure, say N.
2479
2480config LIST_KUNIT_TEST
2481	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2482	depends on KUNIT
2483	default KUNIT_ALL_TESTS
2484	help
2485	  This builds the linked list KUnit test suite.
2486	  It tests that the API and basic functionality of the list_head type
2487	  and associated macros.
2488
2489	  KUnit tests run during boot and output the results to the debug log
2490	  in TAP format (https://testanything.org/). Only useful for kernel devs
2491	  running the KUnit test harness, and not intended for inclusion into a
2492	  production build.
2493
2494	  For more information on KUnit and unit tests in general please refer
2495	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2496
2497	  If unsure, say N.
2498
2499config LINEAR_RANGES_TEST
2500	tristate "KUnit test for linear_ranges"
2501	depends on KUNIT
2502	select LINEAR_RANGES
2503	help
2504	  This builds the linear_ranges unit test, which runs on boot.
2505	  Tests the linear_ranges logic correctness.
2506	  For more information on KUnit and unit tests in general please refer
2507	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2508
2509	  If unsure, say N.
2510
2511config CMDLINE_KUNIT_TEST
2512	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2513	depends on KUNIT
2514	default KUNIT_ALL_TESTS
2515	help
2516	  This builds the cmdline API unit test.
2517	  Tests the logic of API provided by cmdline.c.
2518	  For more information on KUnit and unit tests in general please refer
2519	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2520
2521	  If unsure, say N.
2522
2523config BITS_TEST
2524	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2525	depends on KUNIT
2526	default KUNIT_ALL_TESTS
2527	help
2528	  This builds the bits unit test.
2529	  Tests the logic of macros defined in bits.h.
2530	  For more information on KUnit and unit tests in general please refer
2531	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2532
2533	  If unsure, say N.
2534
2535config SLUB_KUNIT_TEST
2536	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2537	depends on SLUB_DEBUG && KUNIT
2538	default KUNIT_ALL_TESTS
2539	help
2540	  This builds SLUB allocator unit test.
2541	  Tests SLUB cache debugging functionality.
2542	  For more information on KUnit and unit tests in general please refer
2543	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2544
2545	  If unsure, say N.
2546
2547config RATIONAL_KUNIT_TEST
2548	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2549	depends on KUNIT && RATIONAL
2550	default KUNIT_ALL_TESTS
2551	help
2552	  This builds the rational math unit test.
2553	  For more information on KUnit and unit tests in general please refer
2554	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2555
2556	  If unsure, say N.
2557
2558config MEMCPY_KUNIT_TEST
2559	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2560	depends on KUNIT
2561	default KUNIT_ALL_TESTS
2562	help
2563	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2564	  For more information on KUnit and unit tests in general please refer
2565	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2566
2567	  If unsure, say N.
2568
2569config IS_SIGNED_TYPE_KUNIT_TEST
2570	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2571	depends on KUNIT
2572	default KUNIT_ALL_TESTS
2573	help
2574	  Builds unit tests for the is_signed_type() macro.
2575
2576	  For more information on KUnit and unit tests in general please refer
2577	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2578
2579	  If unsure, say N.
2580
2581config OVERFLOW_KUNIT_TEST
2582	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2583	depends on KUNIT
2584	default KUNIT_ALL_TESTS
2585	help
2586	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2587	  related functions.
2588
2589	  For more information on KUnit and unit tests in general please refer
2590	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2591
2592	  If unsure, say N.
2593
2594config STACKINIT_KUNIT_TEST
2595	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2596	depends on KUNIT
2597	default KUNIT_ALL_TESTS
2598	help
2599	  Test if the kernel is zero-initializing stack variables and
2600	  padding. Coverage is controlled by compiler flags,
2601	  CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2602	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2603	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2604
2605config FORTIFY_KUNIT_TEST
2606	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2607	depends on KUNIT && FORTIFY_SOURCE
2608	default KUNIT_ALL_TESTS
2609	help
2610	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2611	  by the str*() and mem*() family of functions. For testing runtime
2612	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2613
2614config HW_BREAKPOINT_KUNIT_TEST
2615	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2616	depends on HAVE_HW_BREAKPOINT
2617	depends on KUNIT=y
2618	default KUNIT_ALL_TESTS
2619	help
2620	  Tests for hw_breakpoint constraints accounting.
2621
2622	  If unsure, say N.
2623
2624config STRSCPY_KUNIT_TEST
2625	tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2626	depends on KUNIT
2627	default KUNIT_ALL_TESTS
2628
2629config SIPHASH_KUNIT_TEST
2630	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2631	depends on KUNIT
2632	default KUNIT_ALL_TESTS
2633	help
2634	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2635	  functions on boot (or module load).
2636
2637	  This is intended to help people writing architecture-specific
2638	  optimized versions.  If unsure, say N.
2639
2640config TEST_UDELAY
2641	tristate "udelay test driver"
2642	help
2643	  This builds the "udelay_test" module that helps to make sure
2644	  that udelay() is working properly.
2645
2646	  If unsure, say N.
2647
2648config TEST_STATIC_KEYS
2649	tristate "Test static keys"
2650	depends on m
2651	help
2652	  Test the static key interfaces.
2653
2654	  If unsure, say N.
2655
2656config TEST_DYNAMIC_DEBUG
2657	tristate "Test DYNAMIC_DEBUG"
2658	depends on DYNAMIC_DEBUG
2659	help
2660	  This module registers a tracer callback to count enabled
2661	  pr_debugs in a 'do_debugging' function, then alters their
2662	  enablements, calls the function, and compares counts.
2663
2664	  If unsure, say N.
2665
2666config TEST_KMOD
2667	tristate "kmod stress tester"
2668	depends on m
2669	depends on NETDEVICES && NET_CORE && INET # for TUN
2670	depends on BLOCK
2671	depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2672	select TEST_LKM
2673	select XFS_FS
2674	select TUN
2675	select BTRFS_FS
2676	help
2677	  Test the kernel's module loading mechanism: kmod. kmod implements
2678	  support to load modules using the Linux kernel's usermode helper.
2679	  This test provides a series of tests against kmod.
2680
2681	  Although technically you can either build test_kmod as a module or
2682	  into the kernel we disallow building it into the kernel since
2683	  it stress tests request_module() and this will very likely cause
2684	  some issues by taking over precious threads available from other
2685	  module load requests, ultimately this could be fatal.
2686
2687	  To run tests run:
2688
2689	  tools/testing/selftests/kmod/kmod.sh --help
2690
2691	  If unsure, say N.
2692
2693config TEST_DEBUG_VIRTUAL
2694	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2695	depends on DEBUG_VIRTUAL
2696	help
2697	  Test the kernel's ability to detect incorrect calls to
2698	  virt_to_phys() done against the non-linear part of the
2699	  kernel's virtual address map.
2700
2701	  If unsure, say N.
2702
2703config TEST_MEMCAT_P
2704	tristate "Test memcat_p() helper function"
2705	help
2706	  Test the memcat_p() helper for correctly merging two
2707	  pointer arrays together.
2708
2709	  If unsure, say N.
2710
2711config TEST_LIVEPATCH
2712	tristate "Test livepatching"
2713	default n
2714	depends on DYNAMIC_DEBUG
2715	depends on LIVEPATCH
2716	depends on m
2717	help
2718	  Test kernel livepatching features for correctness.  The tests will
2719	  load test modules that will be livepatched in various scenarios.
2720
2721	  To run all the livepatching tests:
2722
2723	  make -C tools/testing/selftests TARGETS=livepatch run_tests
2724
2725	  Alternatively, individual tests may be invoked:
2726
2727	  tools/testing/selftests/livepatch/test-callbacks.sh
2728	  tools/testing/selftests/livepatch/test-livepatch.sh
2729	  tools/testing/selftests/livepatch/test-shadow-vars.sh
2730
2731	  If unsure, say N.
2732
2733config TEST_OBJAGG
2734	tristate "Perform selftest on object aggreration manager"
2735	default n
2736	depends on OBJAGG
2737	help
2738	  Enable this option to test object aggregation manager on boot
2739	  (or module load).
2740
2741config TEST_MEMINIT
2742	tristate "Test heap/page initialization"
2743	help
2744	  Test if the kernel is zero-initializing heap and page allocations.
2745	  This can be useful to test init_on_alloc and init_on_free features.
2746
2747	  If unsure, say N.
2748
2749config TEST_HMM
2750	tristate "Test HMM (Heterogeneous Memory Management)"
2751	depends on TRANSPARENT_HUGEPAGE
2752	depends on DEVICE_PRIVATE
2753	select HMM_MIRROR
2754	select MMU_NOTIFIER
2755	help
2756	  This is a pseudo device driver solely for testing HMM.
2757	  Say M here if you want to build the HMM test module.
2758	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2759
2760	  If unsure, say N.
2761
2762config TEST_FREE_PAGES
2763	tristate "Test freeing pages"
2764	help
2765	  Test that a memory leak does not occur due to a race between
2766	  freeing a block of pages and a speculative page reference.
2767	  Loading this module is safe if your kernel has the bug fixed.
2768	  If the bug is not fixed, it will leak gigabytes of memory and
2769	  probably OOM your system.
2770
2771config TEST_FPU
2772	tristate "Test floating point operations in kernel space"
2773	depends on X86 && !KCOV_INSTRUMENT_ALL
2774	help
2775	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2776	  which will trigger a sequence of floating point operations. This is used
2777	  for self-testing floating point control register setting in
2778	  kernel_fpu_begin().
2779
2780	  If unsure, say N.
2781
2782config TEST_CLOCKSOURCE_WATCHDOG
2783	tristate "Test clocksource watchdog in kernel space"
2784	depends on CLOCKSOURCE_WATCHDOG
2785	help
2786	  Enable this option to create a kernel module that will trigger
2787	  a test of the clocksource watchdog.  This module may be loaded
2788	  via modprobe or insmod in which case it will run upon being
2789	  loaded, or it may be built in, in which case it will run
2790	  shortly after boot.
2791
2792	  If unsure, say N.
2793
2794endif # RUNTIME_TESTING_MENU
2795
2796config ARCH_USE_MEMTEST
2797	bool
2798	help
2799	  An architecture should select this when it uses early_memtest()
2800	  during boot process.
2801
2802config MEMTEST
2803	bool "Memtest"
2804	depends on ARCH_USE_MEMTEST
2805	help
2806	  This option adds a kernel parameter 'memtest', which allows memtest
2807	  to be set and executed.
2808	        memtest=0, mean disabled; -- default
2809	        memtest=1, mean do 1 test pattern;
2810	        ...
2811	        memtest=17, mean do 17 test patterns.
2812	  If you are unsure how to answer this question, answer N.
2813
2814
2815
2816config HYPERV_TESTING
2817	bool "Microsoft Hyper-V driver testing"
2818	default n
2819	depends on HYPERV && DEBUG_FS
2820	help
2821	  Select this option to enable Hyper-V vmbus testing.
2822
2823endmenu # "Kernel Testing and Coverage"
2824
2825menu "Rust hacking"
2826
2827config RUST_DEBUG_ASSERTIONS
2828	bool "Debug assertions"
2829	depends on RUST
2830	help
2831	  Enables rustc's `-Cdebug-assertions` codegen option.
2832
2833	  This flag lets you turn `cfg(debug_assertions)` conditional
2834	  compilation on or off. This can be used to enable extra debugging
2835	  code in development but not in production. For example, it controls
2836	  the behavior of the standard library's `debug_assert!` macro.
2837
2838	  Note that this will apply to all Rust code, including `core`.
2839
2840	  If unsure, say N.
2841
2842config RUST_OVERFLOW_CHECKS
2843	bool "Overflow checks"
2844	default y
2845	depends on RUST
2846	help
2847	  Enables rustc's `-Coverflow-checks` codegen option.
2848
2849	  This flag allows you to control the behavior of runtime integer
2850	  overflow. When overflow-checks are enabled, a Rust panic will occur
2851	  on overflow.
2852
2853	  Note that this will apply to all Rust code, including `core`.
2854
2855	  If unsure, say Y.
2856
2857config RUST_BUILD_ASSERT_ALLOW
2858	bool "Allow unoptimized build-time assertions"
2859	depends on RUST
2860	help
2861	  Controls how are `build_error!` and `build_assert!` handled during build.
2862
2863	  If calls to them exist in the binary, it may indicate a violated invariant
2864	  or that the optimizer failed to verify the invariant during compilation.
2865
2866	  This should not happen, thus by default the build is aborted. However,
2867	  as an escape hatch, you can choose Y here to ignore them during build
2868	  and let the check be carried at runtime (with `panic!` being called if
2869	  the check fails).
2870
2871	  If unsure, say N.
2872
2873endmenu # "Rust"
2874
2875source "Documentation/Kconfig"
2876
2877endmenu # Kernel hacking
2878