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