xref: /linux-6.15/lib/Kconfig.debug (revision f65a4868)
1# SPDX-License-Identifier: GPL-2.0-only
2menu "Kernel hacking"
3
4menu "printk and dmesg options"
5
6config PRINTK_TIME
7	bool "Show timing information on printks"
8	depends on PRINTK
9	help
10	  Selecting this option causes time stamps of the printk()
11	  messages to be added to the output of the syslog() system
12	  call and at the console.
13
14	  The timestamp is always recorded internally, and exported
15	  to /dev/kmsg. This flag just specifies if the timestamp should
16	  be included, not that the timestamp is recorded.
17
18	  The behavior is also controlled by the kernel command line
19	  parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
20
21config PRINTK_CALLER
22	bool "Show caller information on printks"
23	depends on PRINTK
24	help
25	  Selecting this option causes printk() to add a caller "thread id" (if
26	  in task context) or a caller "processor id" (if not in task context)
27	  to every message.
28
29	  This option is intended for environments where multiple threads
30	  concurrently call printk() for many times, for it is difficult to
31	  interpret without knowing where these lines (or sometimes individual
32	  line which was divided into multiple lines due to race) came from.
33
34	  Since toggling after boot makes the code racy, currently there is
35	  no option to enable/disable at the kernel command line parameter or
36	  sysfs interface.
37
38config STACKTRACE_BUILD_ID
39	bool "Show build ID information in stacktraces"
40	depends on PRINTK
41	help
42	  Selecting this option adds build ID information for symbols in
43	  stacktraces printed with the printk format '%p[SR]b'.
44
45	  This option is intended for distros where debuginfo is not easily
46	  accessible but can be downloaded given the build ID of the vmlinux or
47	  kernel module where the function is located.
48
49config CONSOLE_LOGLEVEL_DEFAULT
50	int "Default console loglevel (1-15)"
51	range 1 15
52	default "7"
53	help
54	  Default loglevel to determine what will be printed on the console.
55
56	  Setting a default here is equivalent to passing in loglevel=<x> in
57	  the kernel bootargs. loglevel=<x> continues to override whatever
58	  value is specified here as well.
59
60	  Note: This does not affect the log level of un-prefixed printk()
61	  usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
62	  option.
63
64config CONSOLE_LOGLEVEL_QUIET
65	int "quiet console loglevel (1-15)"
66	range 1 15
67	default "4"
68	help
69	  loglevel to use when "quiet" is passed on the kernel commandline.
70
71	  When "quiet" is passed on the kernel commandline this loglevel
72	  will be used as the loglevel. IOW passing "quiet" will be the
73	  equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
74
75config MESSAGE_LOGLEVEL_DEFAULT
76	int "Default message log level (1-7)"
77	range 1 7
78	default "4"
79	help
80	  Default log level for printk statements with no specified priority.
81
82	  This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83	  that are auditing their logs closely may want to set it to a lower
84	  priority.
85
86	  Note: This does not affect what message level gets printed on the console
87	  by default. To change that, use loglevel=<x> in the kernel bootargs,
88	  or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
89
90config BOOT_PRINTK_DELAY
91	bool "Delay each boot printk message by N milliseconds"
92	depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
93	help
94	  This build option allows you to read kernel boot messages
95	  by inserting a short delay after each one.  The delay is
96	  specified in milliseconds on the kernel command line,
97	  using "boot_delay=N".
98
99	  It is likely that you would also need to use "lpj=M" to preset
100	  the "loops per jiffie" value.
101	  See a previous boot log for the "lpj" value to use for your
102	  system, and then set "lpj=M" before setting "boot_delay=N".
103	  NOTE:  Using this option may adversely affect SMP systems.
104	  I.e., processors other than the first one may not boot up.
105	  BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106	  what it believes to be lockup conditions.
107
108config DYNAMIC_DEBUG
109	bool "Enable dynamic printk() support"
110	default n
111	depends on PRINTK
112	depends on (DEBUG_FS || PROC_FS)
113	select DYNAMIC_DEBUG_CORE
114	help
115
116	  Compiles debug level messages into the kernel, which would not
117	  otherwise be available at runtime. These messages can then be
118	  enabled/disabled based on various levels of scope - per source file,
119	  function, module, format string, and line number. This mechanism
120	  implicitly compiles in all pr_debug() and dev_dbg() calls, which
121	  enlarges the kernel text size by about 2%.
122
123	  If a source file is compiled with DEBUG flag set, any
124	  pr_debug() calls in it are enabled by default, but can be
125	  disabled at runtime as below.  Note that DEBUG flag is
126	  turned on by many CONFIG_*DEBUG* options.
127
128	  Usage:
129
130	  Dynamic debugging is controlled via the 'dynamic_debug/control' file,
131	  which is contained in the 'debugfs' filesystem or procfs.
132	  Thus, the debugfs or procfs filesystem must first be mounted before
133	  making use of this feature.
134	  We refer the control file as: <debugfs>/dynamic_debug/control. This
135	  file contains a list of the debug statements that can be enabled. The
136	  format for each line of the file is:
137
138		filename:lineno [module]function flags format
139
140	  filename : source file of the debug statement
141	  lineno : line number of the debug statement
142	  module : module that contains the debug statement
143	  function : function that contains the debug statement
144	  flags : '=p' means the line is turned 'on' for printing
145	  format : the format used for the debug statement
146
147	  From a live system:
148
149		nullarbor:~ # cat <debugfs>/dynamic_debug/control
150		# filename:lineno [module]function flags format
151		fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152		fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153		fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154
155	  Example usage:
156
157		// enable the message at line 1603 of file svcsock.c
158		nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159						<debugfs>/dynamic_debug/control
160
161		// enable all the messages in file svcsock.c
162		nullarbor:~ # echo -n 'file svcsock.c +p' >
163						<debugfs>/dynamic_debug/control
164
165		// enable all the messages in the NFS server module
166		nullarbor:~ # echo -n 'module nfsd +p' >
167						<debugfs>/dynamic_debug/control
168
169		// enable all 12 messages in the function svc_process()
170		nullarbor:~ # echo -n 'func svc_process +p' >
171						<debugfs>/dynamic_debug/control
172
173		// disable all 12 messages in the function svc_process()
174		nullarbor:~ # echo -n 'func svc_process -p' >
175						<debugfs>/dynamic_debug/control
176
177	  See Documentation/admin-guide/dynamic-debug-howto.rst for additional
178	  information.
179
180config DYNAMIC_DEBUG_CORE
181	bool "Enable core function of dynamic debug support"
182	depends on PRINTK
183	depends on (DEBUG_FS || PROC_FS)
184	help
185	  Enable core functional support of dynamic debug. It is useful
186	  when you want to tie dynamic debug to your kernel modules with
187	  DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188	  the case of embedded system where the kernel image size is
189	  sensitive for people.
190
191config SYMBOLIC_ERRNAME
192	bool "Support symbolic error names in printf"
193	default y if PRINTK
194	help
195	  If you say Y here, the kernel's printf implementation will
196	  be able to print symbolic error names such as ENOSPC instead
197	  of the number 28. It makes the kernel image slightly larger
198	  (about 3KB), but can make the kernel logs easier to read.
199
200config DEBUG_BUGVERBOSE
201	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202	depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
203	default y
204	help
205	  Say Y here to make BUG() panics output the file name and line number
206	  of the BUG call as well as the EIP and oops trace.  This aids
207	  debugging but costs about 70-100K of memory.
208
209endmenu # "printk and dmesg options"
210
211config DEBUG_KERNEL
212	bool "Kernel debugging"
213	help
214	  Say Y here if you are developing drivers or trying to debug and
215	  identify kernel problems.
216
217config DEBUG_MISC
218	bool "Miscellaneous debug code"
219	default DEBUG_KERNEL
220	depends on DEBUG_KERNEL
221	help
222	  Say Y here if you need to enable miscellaneous debug code that should
223	  be under a more specific debug option but isn't.
224
225menu "Compile-time checks and compiler options"
226
227config DEBUG_INFO
228	bool
229	help
230	  A kernel debug info option other than "None" has been selected
231	  in the "Debug information" choice below, indicating that debug
232	  information will be generated for build targets.
233
234# Clang is known to generate .{s,u}leb128 with symbol deltas with DWARF5, which
235# some targets may not support: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
236config AS_HAS_NON_CONST_LEB128
237	def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
238
239choice
240	prompt "Debug information"
241	depends on DEBUG_KERNEL
242	help
243	  Selecting something other than "None" results in a kernel image
244	  that will include debugging info resulting in a larger kernel image.
245	  This adds debug symbols to the kernel and modules (gcc -g), and
246	  is needed if you intend to use kernel crashdump or binary object
247	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
248
249	  Choose which version of DWARF debug info to emit. If unsure,
250	  select "Toolchain default".
251
252config DEBUG_INFO_NONE
253	bool "Disable debug information"
254	help
255	  Do not build the kernel with debugging information, which will
256	  result in a faster and smaller build.
257
258config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
259	bool "Rely on the toolchain's implicit default DWARF version"
260	select DEBUG_INFO
261	depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
262	help
263	  The implicit default version of DWARF debug info produced by a
264	  toolchain changes over time.
265
266	  This can break consumers of the debug info that haven't upgraded to
267	  support newer revisions, and prevent testing newer versions, but
268	  those should be less common scenarios.
269
270config DEBUG_INFO_DWARF4
271	bool "Generate DWARF Version 4 debuginfo"
272	select DEBUG_INFO
273	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
274	help
275	  Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
276	  if using clang without clang's integrated assembler, and gdb 7.0+.
277
278	  If you have consumers of DWARF debug info that are not ready for
279	  newer revisions of DWARF, you may wish to choose this or have your
280	  config select this.
281
282config DEBUG_INFO_DWARF5
283	bool "Generate DWARF Version 5 debuginfo"
284	select DEBUG_INFO
285	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
286	help
287	  Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
288	  5.0+ accepts the -gdwarf-5 flag but only had partial support for some
289	  draft features until 7.0), and gdb 8.0+.
290
291	  Changes to the structure of debug info in Version 5 allow for around
292	  15-18% savings in resulting image and debug info section sizes as
293	  compared to DWARF Version 4. DWARF Version 5 standardizes previous
294	  extensions such as accelerators for symbol indexing and the format
295	  for fission (.dwo/.dwp) files. Users may not want to select this
296	  config if they rely on tooling that has not yet been updated to
297	  support DWARF Version 5.
298
299endchoice # "Debug information"
300
301if DEBUG_INFO
302
303config DEBUG_INFO_REDUCED
304	bool "Reduce debugging information"
305	help
306	  If you say Y here gcc is instructed to generate less debugging
307	  information for structure types. This means that tools that
308	  need full debugging information (like kgdb or systemtap) won't
309	  be happy. But if you merely need debugging information to
310	  resolve line numbers there is no loss. Advantage is that
311	  build directory object sizes shrink dramatically over a full
312	  DEBUG_INFO build and compile times are reduced too.
313	  Only works with newer gcc versions.
314
315choice
316	prompt "Compressed Debug information"
317	help
318	  Compress the resulting debug info. Results in smaller debug info sections,
319	  but requires that consumers are able to decompress the results.
320
321	  If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
322
323config DEBUG_INFO_COMPRESSED_NONE
324	bool "Don't compress debug information"
325	help
326	  Don't compress debug info sections.
327
328config DEBUG_INFO_COMPRESSED_ZLIB
329	bool "Compress debugging information with zlib"
330	depends on $(cc-option,-gz=zlib)
331	depends on $(ld-option,--compress-debug-sections=zlib)
332	help
333	  Compress the debug information using zlib.  Requires GCC 5.0+ or Clang
334	  5.0+, binutils 2.26+, and zlib.
335
336	  Users of dpkg-deb via scripts/package/builddeb may find an increase in
337	  size of their debug .deb packages with this config set, due to the
338	  debug info being compressed with zlib, then the object files being
339	  recompressed with a different compression scheme. But this is still
340	  preferable to setting $KDEB_COMPRESS to "none" which would be even
341	  larger.
342
343config DEBUG_INFO_COMPRESSED_ZSTD
344	bool "Compress debugging information with zstd"
345	depends on $(cc-option,-gz=zstd)
346	depends on $(ld-option,--compress-debug-sections=zstd)
347	help
348	  Compress the debug information using zstd.  This may provide better
349	  compression than zlib, for about the same time costs, but requires newer
350	  toolchain support.  Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
351	  zstd.
352
353endchoice # "Compressed Debug information"
354
355config DEBUG_INFO_SPLIT
356	bool "Produce split debuginfo in .dwo files"
357	depends on $(cc-option,-gsplit-dwarf)
358	help
359	  Generate debug info into separate .dwo files. This significantly
360	  reduces the build directory size for builds with DEBUG_INFO,
361	  because it stores the information only once on disk in .dwo
362	  files instead of multiple times in object files and executables.
363	  In addition the debug information is also compressed.
364
365	  Requires recent gcc (4.7+) and recent gdb/binutils.
366	  Any tool that packages or reads debug information would need
367	  to know about the .dwo files and include them.
368	  Incompatible with older versions of ccache.
369
370config DEBUG_INFO_BTF
371	bool "Generate BTF typeinfo"
372	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
373	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
374	depends on BPF_SYSCALL
375	depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
376	help
377	  Generate deduplicated BTF type information from DWARF debug info.
378	  Turning this on expects presence of pahole tool, which will convert
379	  DWARF type info into equivalent deduplicated BTF type info.
380
381config PAHOLE_HAS_SPLIT_BTF
382	def_bool PAHOLE_VERSION >= 119
383
384config PAHOLE_HAS_BTF_TAG
385	def_bool PAHOLE_VERSION >= 123
386	depends on CC_IS_CLANG
387	help
388	  Decide whether pahole emits btf_tag attributes (btf_type_tag and
389	  btf_decl_tag) or not. Currently only clang compiler implements
390	  these attributes, so make the config depend on CC_IS_CLANG.
391
392config DEBUG_INFO_BTF_MODULES
393	def_bool y
394	depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
395	help
396	  Generate compact split BTF type information for kernel modules.
397
398config MODULE_ALLOW_BTF_MISMATCH
399	bool "Allow loading modules with non-matching BTF type info"
400	depends on DEBUG_INFO_BTF_MODULES
401	help
402	  For modules whose split BTF does not match vmlinux, load without
403	  BTF rather than refusing to load. The default behavior with
404	  module BTF enabled is to reject modules with such mismatches;
405	  this option will still load module BTF where possible but ignore
406	  it when a mismatch is found.
407
408config GDB_SCRIPTS
409	bool "Provide GDB scripts for kernel debugging"
410	help
411	  This creates the required links to GDB helper scripts in the
412	  build directory. If you load vmlinux into gdb, the helper
413	  scripts will be automatically imported by gdb as well, and
414	  additional functions are available to analyze a Linux kernel
415	  instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
416	  for further details.
417
418endif # DEBUG_INFO
419
420config FRAME_WARN
421	int "Warn for stack frames larger than"
422	range 0 8192
423	default 0 if KMSAN
424	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
425	default 2048 if PARISC
426	default 1536 if (!64BIT && XTENSA)
427	default 1024 if !64BIT
428	default 2048 if 64BIT
429	help
430	  Tell the compiler to warn at build time for stack frames larger than this.
431	  Setting this too low will cause a lot of warnings.
432	  Setting it to 0 disables the warning.
433
434config STRIP_ASM_SYMS
435	bool "Strip assembler-generated symbols during link"
436	default n
437	help
438	  Strip internal assembler-generated symbols during a link (symbols
439	  that look like '.Lxxx') so they don't pollute the output of
440	  get_wchan() and suchlike.
441
442config READABLE_ASM
443	bool "Generate readable assembler code"
444	depends on DEBUG_KERNEL
445	depends on CC_IS_GCC
446	help
447	  Disable some compiler optimizations that tend to generate human unreadable
448	  assembler output. This may make the kernel slightly slower, but it helps
449	  to keep kernel developers who have to stare a lot at assembler listings
450	  sane.
451
452config HEADERS_INSTALL
453	bool "Install uapi headers to usr/include"
454	depends on !UML
455	help
456	  This option will install uapi headers (headers exported to user-space)
457	  into the usr/include directory for use during the kernel build.
458	  This is unneeded for building the kernel itself, but needed for some
459	  user-space program samples. It is also needed by some features such
460	  as uapi header sanity checks.
461
462config DEBUG_SECTION_MISMATCH
463	bool "Enable full Section mismatch analysis"
464	depends on CC_IS_GCC
465	help
466	  The section mismatch analysis checks if there are illegal
467	  references from one section to another section.
468	  During linktime or runtime, some sections are dropped;
469	  any use of code/data previously in these sections would
470	  most likely result in an oops.
471	  In the code, functions and variables are annotated with
472	  __init,, etc. (see the full list in include/linux/init.h),
473	  which results in the code/data being placed in specific sections.
474	  The section mismatch analysis is always performed after a full
475	  kernel build, and enabling this option causes the following
476	  additional step to occur:
477	  - Add the option -fno-inline-functions-called-once to gcc commands.
478	    When inlining a function annotated with __init in a non-init
479	    function, we would lose the section information and thus
480	    the analysis would not catch the illegal reference.
481	    This option tells gcc to inline less (but it does result in
482	    a larger kernel).
483
484config SECTION_MISMATCH_WARN_ONLY
485	bool "Make section mismatch errors non-fatal"
486	default y
487	help
488	  If you say N here, the build process will fail if there are any
489	  section mismatch, instead of just throwing warnings.
490
491	  If unsure, say Y.
492
493config DEBUG_FORCE_FUNCTION_ALIGN_64B
494	bool "Force all function address 64B aligned"
495	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
496	help
497	  There are cases that a commit from one domain changes the function
498	  address alignment of other domains, and cause magic performance
499	  bump (regression or improvement). Enable this option will help to
500	  verify if the bump is caused by function alignment changes, while
501	  it will slightly increase the kernel size and affect icache usage.
502
503	  It is mainly for debug and performance tuning use.
504
505#
506# Select this config option from the architecture Kconfig, if it
507# is preferred to always offer frame pointers as a config
508# option on the architecture (regardless of KERNEL_DEBUG):
509#
510config ARCH_WANT_FRAME_POINTERS
511	bool
512
513config FRAME_POINTER
514	bool "Compile the kernel with frame pointers"
515	depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
516	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
517	help
518	  If you say Y here the resulting kernel image will be slightly
519	  larger and slower, but it gives very useful debugging information
520	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
521
522config OBJTOOL
523	bool
524
525config STACK_VALIDATION
526	bool "Compile-time stack metadata validation"
527	depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
528	select OBJTOOL
529	default n
530	help
531	  Validate frame pointer rules at compile-time.  This helps ensure that
532	  runtime stack traces are more reliable.
533
534	  For more information, see
535	  tools/objtool/Documentation/objtool.txt.
536
537config NOINSTR_VALIDATION
538	bool
539	depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
540	select OBJTOOL
541	default y
542
543config VMLINUX_MAP
544	bool "Generate vmlinux.map file when linking"
545	depends on EXPERT
546	help
547	  Selecting this option will pass "-Map=vmlinux.map" to ld
548	  when linking vmlinux. That file can be useful for verifying
549	  and debugging magic section games, and for seeing which
550	  pieces of code get eliminated with
551	  CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
552
553config DEBUG_FORCE_WEAK_PER_CPU
554	bool "Force weak per-cpu definitions"
555	depends on DEBUG_KERNEL
556	help
557	  s390 and alpha require percpu variables in modules to be
558	  defined weak to work around addressing range issue which
559	  puts the following two restrictions on percpu variable
560	  definitions.
561
562	  1. percpu symbols must be unique whether static or not
563	  2. percpu variables can't be defined inside a function
564
565	  To ensure that generic code follows the above rules, this
566	  option forces all percpu variables to be defined as weak.
567
568endmenu # "Compiler options"
569
570menu "Generic Kernel Debugging Instruments"
571
572config MAGIC_SYSRQ
573	bool "Magic SysRq key"
574	depends on !UML
575	help
576	  If you say Y here, you will have some control over the system even
577	  if the system crashes for example during kernel debugging (e.g., you
578	  will be able to flush the buffer cache to disk, reboot the system
579	  immediately or dump some status information). This is accomplished
580	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
581	  also works on a serial console (on PC hardware at least), if you
582	  send a BREAK and then within 5 seconds a command keypress. The
583	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
584	  Don't say Y unless you really know what this hack does.
585
586config MAGIC_SYSRQ_DEFAULT_ENABLE
587	hex "Enable magic SysRq key functions by default"
588	depends on MAGIC_SYSRQ
589	default 0x1
590	help
591	  Specifies which SysRq key functions are enabled by default.
592	  This may be set to 1 or 0 to enable or disable them all, or
593	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
594
595config MAGIC_SYSRQ_SERIAL
596	bool "Enable magic SysRq key over serial"
597	depends on MAGIC_SYSRQ
598	default y
599	help
600	  Many embedded boards have a disconnected TTL level serial which can
601	  generate some garbage that can lead to spurious false sysrq detects.
602	  This option allows you to decide whether you want to enable the
603	  magic SysRq key.
604
605config MAGIC_SYSRQ_SERIAL_SEQUENCE
606	string "Char sequence that enables magic SysRq over serial"
607	depends on MAGIC_SYSRQ_SERIAL
608	default ""
609	help
610	  Specifies a sequence of characters that can follow BREAK to enable
611	  SysRq on a serial console.
612
613	  If unsure, leave an empty string and the option will not be enabled.
614
615config DEBUG_FS
616	bool "Debug Filesystem"
617	help
618	  debugfs is a virtual file system that kernel developers use to put
619	  debugging files into.  Enable this option to be able to read and
620	  write to these files.
621
622	  For detailed documentation on the debugfs API, see
623	  Documentation/filesystems/.
624
625	  If unsure, say N.
626
627choice
628	prompt "Debugfs default access"
629	depends on DEBUG_FS
630	default DEBUG_FS_ALLOW_ALL
631	help
632	  This selects the default access restrictions for debugfs.
633	  It can be overridden with kernel command line option
634	  debugfs=[on,no-mount,off]. The restrictions apply for API access
635	  and filesystem registration.
636
637config DEBUG_FS_ALLOW_ALL
638	bool "Access normal"
639	help
640	  No restrictions apply. Both API and filesystem registration
641	  is on. This is the normal default operation.
642
643config DEBUG_FS_DISALLOW_MOUNT
644	bool "Do not register debugfs as filesystem"
645	help
646	  The API is open but filesystem is not loaded. Clients can still do
647	  their work and read with debug tools that do not need
648	  debugfs filesystem.
649
650config DEBUG_FS_ALLOW_NONE
651	bool "No access"
652	help
653	  Access is off. Clients get -PERM when trying to create nodes in
654	  debugfs tree and debugfs is not registered as a filesystem.
655	  Client can then back-off or continue without debugfs access.
656
657endchoice
658
659source "lib/Kconfig.kgdb"
660source "lib/Kconfig.ubsan"
661source "lib/Kconfig.kcsan"
662
663endmenu
664
665menu "Networking Debugging"
666
667source "net/Kconfig.debug"
668
669endmenu # "Networking Debugging"
670
671menu "Memory Debugging"
672
673source "mm/Kconfig.debug"
674
675config DEBUG_OBJECTS
676	bool "Debug object operations"
677	depends on DEBUG_KERNEL
678	help
679	  If you say Y here, additional code will be inserted into the
680	  kernel to track the life time of various objects and validate
681	  the operations on those objects.
682
683config DEBUG_OBJECTS_SELFTEST
684	bool "Debug objects selftest"
685	depends on DEBUG_OBJECTS
686	help
687	  This enables the selftest of the object debug code.
688
689config DEBUG_OBJECTS_FREE
690	bool "Debug objects in freed memory"
691	depends on DEBUG_OBJECTS
692	help
693	  This enables checks whether a k/v free operation frees an area
694	  which contains an object which has not been deactivated
695	  properly. This can make kmalloc/kfree-intensive workloads
696	  much slower.
697
698config DEBUG_OBJECTS_TIMERS
699	bool "Debug timer objects"
700	depends on DEBUG_OBJECTS
701	help
702	  If you say Y here, additional code will be inserted into the
703	  timer routines to track the life time of timer objects and
704	  validate the timer operations.
705
706config DEBUG_OBJECTS_WORK
707	bool "Debug work objects"
708	depends on DEBUG_OBJECTS
709	help
710	  If you say Y here, additional code will be inserted into the
711	  work queue routines to track the life time of work objects and
712	  validate the work operations.
713
714config DEBUG_OBJECTS_RCU_HEAD
715	bool "Debug RCU callbacks objects"
716	depends on DEBUG_OBJECTS
717	help
718	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
719
720config DEBUG_OBJECTS_PERCPU_COUNTER
721	bool "Debug percpu counter objects"
722	depends on DEBUG_OBJECTS
723	help
724	  If you say Y here, additional code will be inserted into the
725	  percpu counter routines to track the life time of percpu counter
726	  objects and validate the percpu counter operations.
727
728config DEBUG_OBJECTS_ENABLE_DEFAULT
729	int "debug_objects bootup default value (0-1)"
730	range 0 1
731	default "1"
732	depends on DEBUG_OBJECTS
733	help
734	  Debug objects boot parameter default value
735
736config SHRINKER_DEBUG
737	bool "Enable shrinker debugging support"
738	depends on DEBUG_FS
739	help
740	  Say Y to enable the shrinker debugfs interface which provides
741	  visibility into the kernel memory shrinkers subsystem.
742	  Disable it to avoid an extra memory footprint.
743
744config HAVE_DEBUG_KMEMLEAK
745	bool
746
747config DEBUG_KMEMLEAK
748	bool "Kernel memory leak detector"
749	depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
750	select DEBUG_FS
751	select STACKTRACE if STACKTRACE_SUPPORT
752	select KALLSYMS
753	select CRC32
754	help
755	  Say Y here if you want to enable the memory leak
756	  detector. The memory allocation/freeing is traced in a way
757	  similar to the Boehm's conservative garbage collector, the
758	  difference being that the orphan objects are not freed but
759	  only shown in /sys/kernel/debug/kmemleak. Enabling this
760	  feature will introduce an overhead to memory
761	  allocations. See Documentation/dev-tools/kmemleak.rst for more
762	  details.
763
764	  Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
765	  of finding leaks due to the slab objects poisoning.
766
767	  In order to access the kmemleak file, debugfs needs to be
768	  mounted (usually at /sys/kernel/debug).
769
770config DEBUG_KMEMLEAK_MEM_POOL_SIZE
771	int "Kmemleak memory pool size"
772	depends on DEBUG_KMEMLEAK
773	range 200 1000000
774	default 16000
775	help
776	  Kmemleak must track all the memory allocations to avoid
777	  reporting false positives. Since memory may be allocated or
778	  freed before kmemleak is fully initialised, use a static pool
779	  of metadata objects to track such callbacks. After kmemleak is
780	  fully initialised, this memory pool acts as an emergency one
781	  if slab allocations fail.
782
783config DEBUG_KMEMLEAK_TEST
784	tristate "Simple test for the kernel memory leak detector"
785	depends on DEBUG_KMEMLEAK && m
786	help
787	  This option enables a module that explicitly leaks memory.
788
789	  If unsure, say N.
790
791config DEBUG_KMEMLEAK_DEFAULT_OFF
792	bool "Default kmemleak to off"
793	depends on DEBUG_KMEMLEAK
794	help
795	  Say Y here to disable kmemleak by default. It can then be enabled
796	  on the command line via kmemleak=on.
797
798config DEBUG_KMEMLEAK_AUTO_SCAN
799	bool "Enable kmemleak auto scan thread on boot up"
800	default y
801	depends on DEBUG_KMEMLEAK
802	help
803	  Depending on the cpu, kmemleak scan may be cpu intensive and can
804	  stall user tasks at times. This option enables/disables automatic
805	  kmemleak scan at boot up.
806
807	  Say N here to disable kmemleak auto scan thread to stop automatic
808	  scanning. Disabling this option disables automatic reporting of
809	  memory leaks.
810
811	  If unsure, say Y.
812
813config DEBUG_STACK_USAGE
814	bool "Stack utilization instrumentation"
815	depends on DEBUG_KERNEL && !IA64
816	help
817	  Enables the display of the minimum amount of free stack which each
818	  task has ever had available in the sysrq-T and sysrq-P debug output.
819
820	  This option will slow down process creation somewhat.
821
822config SCHED_STACK_END_CHECK
823	bool "Detect stack corruption on calls to schedule()"
824	depends on DEBUG_KERNEL
825	default n
826	help
827	  This option checks for a stack overrun on calls to schedule().
828	  If the stack end location is found to be over written always panic as
829	  the content of the corrupted region can no longer be trusted.
830	  This is to ensure no erroneous behaviour occurs which could result in
831	  data corruption or a sporadic crash at a later stage once the region
832	  is examined. The runtime overhead introduced is minimal.
833
834config ARCH_HAS_DEBUG_VM_PGTABLE
835	bool
836	help
837	  An architecture should select this when it can successfully
838	  build and run DEBUG_VM_PGTABLE.
839
840config DEBUG_VM_IRQSOFF
841	def_bool DEBUG_VM && !PREEMPT_RT
842
843config DEBUG_VM
844	bool "Debug VM"
845	depends on DEBUG_KERNEL
846	help
847	  Enable this to turn on extended checks in the virtual-memory system
848	  that may impact performance.
849
850	  If unsure, say N.
851
852config DEBUG_VM_MAPLE_TREE
853	bool "Debug VM maple trees"
854	depends on DEBUG_VM
855	select DEBUG_MAPLE_TREE
856	help
857	  Enable VM maple tree debugging information and extra validations.
858
859	  If unsure, say N.
860
861config DEBUG_VM_RB
862	bool "Debug VM red-black trees"
863	depends on DEBUG_VM
864	help
865	  Enable VM red-black tree debugging information and extra validations.
866
867	  If unsure, say N.
868
869config DEBUG_VM_PGFLAGS
870	bool "Debug page-flags operations"
871	depends on DEBUG_VM
872	help
873	  Enables extra validation on page flags operations.
874
875	  If unsure, say N.
876
877config DEBUG_VM_PGTABLE
878	bool "Debug arch page table for semantics compliance"
879	depends on MMU
880	depends on ARCH_HAS_DEBUG_VM_PGTABLE
881	default y if DEBUG_VM
882	help
883	  This option provides a debug method which can be used to test
884	  architecture page table helper functions on various platforms in
885	  verifying if they comply with expected generic MM semantics. This
886	  will help architecture code in making sure that any changes or
887	  new additions of these helpers still conform to expected
888	  semantics of the generic MM. Platforms will have to opt in for
889	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
890
891	  If unsure, say N.
892
893config ARCH_HAS_DEBUG_VIRTUAL
894	bool
895
896config DEBUG_VIRTUAL
897	bool "Debug VM translations"
898	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
899	help
900	  Enable some costly sanity checks in virtual to page code. This can
901	  catch mistakes with virt_to_page() and friends.
902
903	  If unsure, say N.
904
905config DEBUG_NOMMU_REGIONS
906	bool "Debug the global anon/private NOMMU mapping region tree"
907	depends on DEBUG_KERNEL && !MMU
908	help
909	  This option causes the global tree of anonymous and private mapping
910	  regions to be regularly checked for invalid topology.
911
912config DEBUG_MEMORY_INIT
913	bool "Debug memory initialisation" if EXPERT
914	default !EXPERT
915	help
916	  Enable this for additional checks during memory initialisation.
917	  The sanity checks verify aspects of the VM such as the memory model
918	  and other information provided by the architecture. Verbose
919	  information will be printed at KERN_DEBUG loglevel depending
920	  on the mminit_loglevel= command-line option.
921
922	  If unsure, say Y
923
924config MEMORY_NOTIFIER_ERROR_INJECT
925	tristate "Memory hotplug notifier error injection module"
926	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
927	help
928	  This option provides the ability to inject artificial errors to
929	  memory hotplug notifier chain callbacks.  It is controlled through
930	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
931
932	  If the notifier call chain should be failed with some events
933	  notified, write the error code to "actions/<notifier event>/error".
934
935	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
936
937	  # cd /sys/kernel/debug/notifier-error-inject/memory
938	  # echo -12 > actions/MEM_GOING_OFFLINE/error
939	  # echo offline > /sys/devices/system/memory/memoryXXX/state
940	  bash: echo: write error: Cannot allocate memory
941
942	  To compile this code as a module, choose M here: the module will
943	  be called memory-notifier-error-inject.
944
945	  If unsure, say N.
946
947config DEBUG_PER_CPU_MAPS
948	bool "Debug access to per_cpu maps"
949	depends on DEBUG_KERNEL
950	depends on SMP
951	help
952	  Say Y to verify that the per_cpu map being accessed has
953	  been set up. This adds a fair amount of code to kernel memory
954	  and decreases performance.
955
956	  Say N if unsure.
957
958config DEBUG_KMAP_LOCAL
959	bool "Debug kmap_local temporary mappings"
960	depends on DEBUG_KERNEL && KMAP_LOCAL
961	help
962	  This option enables additional error checking for the kmap_local
963	  infrastructure.  Disable for production use.
964
965config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
966	bool
967
968config DEBUG_KMAP_LOCAL_FORCE_MAP
969	bool "Enforce kmap_local temporary mappings"
970	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
971	select KMAP_LOCAL
972	select DEBUG_KMAP_LOCAL
973	help
974	  This option enforces temporary mappings through the kmap_local
975	  mechanism for non-highmem pages and on non-highmem systems.
976	  Disable this for production systems!
977
978config DEBUG_HIGHMEM
979	bool "Highmem debugging"
980	depends on DEBUG_KERNEL && HIGHMEM
981	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
982	select DEBUG_KMAP_LOCAL
983	help
984	  This option enables additional error checking for high memory
985	  systems.  Disable for production systems.
986
987config HAVE_DEBUG_STACKOVERFLOW
988	bool
989
990config DEBUG_STACKOVERFLOW
991	bool "Check for stack overflows"
992	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
993	help
994	  Say Y here if you want to check for overflows of kernel, IRQ
995	  and exception stacks (if your architecture uses them). This
996	  option will show detailed messages if free stack space drops
997	  below a certain limit.
998
999	  These kinds of bugs usually occur when call-chains in the
1000	  kernel get too deep, especially when interrupts are
1001	  involved.
1002
1003	  Use this in cases where you see apparently random memory
1004	  corruption, especially if it appears in 'struct thread_info'
1005
1006	  If in doubt, say "N".
1007
1008source "lib/Kconfig.kasan"
1009source "lib/Kconfig.kfence"
1010source "lib/Kconfig.kmsan"
1011
1012endmenu # "Memory Debugging"
1013
1014config DEBUG_SHIRQ
1015	bool "Debug shared IRQ handlers"
1016	depends on DEBUG_KERNEL
1017	help
1018	  Enable this to generate a spurious interrupt just before a shared
1019	  interrupt handler is deregistered (generating one when registering
1020	  is currently disabled). Drivers need to handle this correctly. Some
1021	  don't and need to be caught.
1022
1023menu "Debug Oops, Lockups and Hangs"
1024
1025config PANIC_ON_OOPS
1026	bool "Panic on Oops"
1027	help
1028	  Say Y here to enable the kernel to panic when it oopses. This
1029	  has the same effect as setting oops=panic on the kernel command
1030	  line.
1031
1032	  This feature is useful to ensure that the kernel does not do
1033	  anything erroneous after an oops which could result in data
1034	  corruption or other issues.
1035
1036	  Say N if unsure.
1037
1038config PANIC_ON_OOPS_VALUE
1039	int
1040	range 0 1
1041	default 0 if !PANIC_ON_OOPS
1042	default 1 if PANIC_ON_OOPS
1043
1044config PANIC_TIMEOUT
1045	int "panic timeout"
1046	default 0
1047	help
1048	  Set the timeout value (in seconds) until a reboot occurs when
1049	  the kernel panics. If n = 0, then we wait forever. A timeout
1050	  value n > 0 will wait n seconds before rebooting, while a timeout
1051	  value n < 0 will reboot immediately.
1052
1053config LOCKUP_DETECTOR
1054	bool
1055
1056config SOFTLOCKUP_DETECTOR
1057	bool "Detect Soft Lockups"
1058	depends on DEBUG_KERNEL && !S390
1059	select LOCKUP_DETECTOR
1060	help
1061	  Say Y here to enable the kernel to act as a watchdog to detect
1062	  soft lockups.
1063
1064	  Softlockups are bugs that cause the kernel to loop in kernel
1065	  mode for more than 20 seconds, without giving other tasks a
1066	  chance to run.  The current stack trace is displayed upon
1067	  detection and the system will stay locked up.
1068
1069config BOOTPARAM_SOFTLOCKUP_PANIC
1070	bool "Panic (Reboot) On Soft Lockups"
1071	depends on SOFTLOCKUP_DETECTOR
1072	help
1073	  Say Y here to enable the kernel to panic on "soft lockups",
1074	  which are bugs that cause the kernel to loop in kernel
1075	  mode for more than 20 seconds (configurable using the watchdog_thresh
1076	  sysctl), without giving other tasks a chance to run.
1077
1078	  The panic can be used in combination with panic_timeout,
1079	  to cause the system to reboot automatically after a
1080	  lockup has been detected. This feature is useful for
1081	  high-availability systems that have uptime guarantees and
1082	  where a lockup must be resolved ASAP.
1083
1084	  Say N if unsure.
1085
1086config HARDLOCKUP_DETECTOR_PERF
1087	bool
1088	select SOFTLOCKUP_DETECTOR
1089
1090#
1091# Enables a timestamp based low pass filter to compensate for perf based
1092# hard lockup detection which runs too fast due to turbo modes.
1093#
1094config HARDLOCKUP_CHECK_TIMESTAMP
1095	bool
1096
1097#
1098# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1099# lockup detector rather than the perf based detector.
1100#
1101config HARDLOCKUP_DETECTOR
1102	bool "Detect Hard Lockups"
1103	depends on DEBUG_KERNEL && !S390
1104	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1105	select LOCKUP_DETECTOR
1106	select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1107	help
1108	  Say Y here to enable the kernel to act as a watchdog to detect
1109	  hard lockups.
1110
1111	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1112	  for more than 10 seconds, without letting other interrupts have a
1113	  chance to run.  The current stack trace is displayed upon detection
1114	  and the system will stay locked up.
1115
1116config BOOTPARAM_HARDLOCKUP_PANIC
1117	bool "Panic (Reboot) On Hard Lockups"
1118	depends on HARDLOCKUP_DETECTOR
1119	help
1120	  Say Y here to enable the kernel to panic on "hard lockups",
1121	  which are bugs that cause the kernel to loop in kernel
1122	  mode with interrupts disabled for more than 10 seconds (configurable
1123	  using the watchdog_thresh sysctl).
1124
1125	  Say N if unsure.
1126
1127config DETECT_HUNG_TASK
1128	bool "Detect Hung Tasks"
1129	depends on DEBUG_KERNEL
1130	default SOFTLOCKUP_DETECTOR
1131	help
1132	  Say Y here to enable the kernel to detect "hung tasks",
1133	  which are bugs that cause the task to be stuck in
1134	  uninterruptible "D" state indefinitely.
1135
1136	  When a hung task is detected, the kernel will print the
1137	  current stack trace (which you should report), but the
1138	  task will stay in uninterruptible state. If lockdep is
1139	  enabled then all held locks will also be reported. This
1140	  feature has negligible overhead.
1141
1142config DEFAULT_HUNG_TASK_TIMEOUT
1143	int "Default timeout for hung task detection (in seconds)"
1144	depends on DETECT_HUNG_TASK
1145	default 120
1146	help
1147	  This option controls the default timeout (in seconds) used
1148	  to determine when a task has become non-responsive and should
1149	  be considered hung.
1150
1151	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1152	  sysctl or by writing a value to
1153	  /proc/sys/kernel/hung_task_timeout_secs.
1154
1155	  A timeout of 0 disables the check.  The default is two minutes.
1156	  Keeping the default should be fine in most cases.
1157
1158config BOOTPARAM_HUNG_TASK_PANIC
1159	bool "Panic (Reboot) On Hung Tasks"
1160	depends on DETECT_HUNG_TASK
1161	help
1162	  Say Y here to enable the kernel to panic on "hung tasks",
1163	  which are bugs that cause the kernel to leave a task stuck
1164	  in uninterruptible "D" state.
1165
1166	  The panic can be used in combination with panic_timeout,
1167	  to cause the system to reboot automatically after a
1168	  hung task has been detected. This feature is useful for
1169	  high-availability systems that have uptime guarantees and
1170	  where a hung tasks must be resolved ASAP.
1171
1172	  Say N if unsure.
1173
1174config WQ_WATCHDOG
1175	bool "Detect Workqueue Stalls"
1176	depends on DEBUG_KERNEL
1177	help
1178	  Say Y here to enable stall detection on workqueues.  If a
1179	  worker pool doesn't make forward progress on a pending work
1180	  item for over a given amount of time, 30s by default, a
1181	  warning message is printed along with dump of workqueue
1182	  state.  This can be configured through kernel parameter
1183	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1184
1185config TEST_LOCKUP
1186	tristate "Test module to generate lockups"
1187	depends on m
1188	help
1189	  This builds the "test_lockup" module that helps to make sure
1190	  that watchdogs and lockup detectors are working properly.
1191
1192	  Depending on module parameters it could emulate soft or hard
1193	  lockup, "hung task", or locking arbitrary lock for a long time.
1194	  Also it could generate series of lockups with cooling-down periods.
1195
1196	  If unsure, say N.
1197
1198endmenu # "Debug lockups and hangs"
1199
1200menu "Scheduler Debugging"
1201
1202config SCHED_DEBUG
1203	bool "Collect scheduler debugging info"
1204	depends on DEBUG_KERNEL && PROC_FS
1205	default y
1206	help
1207	  If you say Y here, the /proc/sched_debug file will be provided
1208	  that can help debug the scheduler. The runtime overhead of this
1209	  option is minimal.
1210
1211config SCHED_INFO
1212	bool
1213	default n
1214
1215config SCHEDSTATS
1216	bool "Collect scheduler statistics"
1217	depends on DEBUG_KERNEL && PROC_FS
1218	select SCHED_INFO
1219	help
1220	  If you say Y here, additional code will be inserted into the
1221	  scheduler and related routines to collect statistics about
1222	  scheduler behavior and provide them in /proc/schedstat.  These
1223	  stats may be useful for both tuning and debugging the scheduler
1224	  If you aren't debugging the scheduler or trying to tune a specific
1225	  application, you can say N to avoid the very slight overhead
1226	  this adds.
1227
1228endmenu
1229
1230config DEBUG_TIMEKEEPING
1231	bool "Enable extra timekeeping sanity checking"
1232	help
1233	  This option will enable additional timekeeping sanity checks
1234	  which may be helpful when diagnosing issues where timekeeping
1235	  problems are suspected.
1236
1237	  This may include checks in the timekeeping hotpaths, so this
1238	  option may have a (very small) performance impact to some
1239	  workloads.
1240
1241	  If unsure, say N.
1242
1243config DEBUG_PREEMPT
1244	bool "Debug preemptible kernel"
1245	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1246	default y
1247	help
1248	  If you say Y here then the kernel will use a debug variant of the
1249	  commonly used smp_processor_id() function and will print warnings
1250	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1251	  will detect preemption count underflows.
1252
1253menu "Lock Debugging (spinlocks, mutexes, etc...)"
1254
1255config LOCK_DEBUGGING_SUPPORT
1256	bool
1257	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1258	default y
1259
1260config PROVE_LOCKING
1261	bool "Lock debugging: prove locking correctness"
1262	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1263	select LOCKDEP
1264	select DEBUG_SPINLOCK
1265	select DEBUG_MUTEXES if !PREEMPT_RT
1266	select DEBUG_RT_MUTEXES if RT_MUTEXES
1267	select DEBUG_RWSEMS
1268	select DEBUG_WW_MUTEX_SLOWPATH
1269	select DEBUG_LOCK_ALLOC
1270	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1271	select TRACE_IRQFLAGS
1272	default n
1273	help
1274	 This feature enables the kernel to prove that all locking
1275	 that occurs in the kernel runtime is mathematically
1276	 correct: that under no circumstance could an arbitrary (and
1277	 not yet triggered) combination of observed locking
1278	 sequences (on an arbitrary number of CPUs, running an
1279	 arbitrary number of tasks and interrupt contexts) cause a
1280	 deadlock.
1281
1282	 In short, this feature enables the kernel to report locking
1283	 related deadlocks before they actually occur.
1284
1285	 The proof does not depend on how hard and complex a
1286	 deadlock scenario would be to trigger: how many
1287	 participant CPUs, tasks and irq-contexts would be needed
1288	 for it to trigger. The proof also does not depend on
1289	 timing: if a race and a resulting deadlock is possible
1290	 theoretically (no matter how unlikely the race scenario
1291	 is), it will be proven so and will immediately be
1292	 reported by the kernel (once the event is observed that
1293	 makes the deadlock theoretically possible).
1294
1295	 If a deadlock is impossible (i.e. the locking rules, as
1296	 observed by the kernel, are mathematically correct), the
1297	 kernel reports nothing.
1298
1299	 NOTE: this feature can also be enabled for rwlocks, mutexes
1300	 and rwsems - in which case all dependencies between these
1301	 different locking variants are observed and mapped too, and
1302	 the proof of observed correctness is also maintained for an
1303	 arbitrary combination of these separate locking variants.
1304
1305	 For more details, see Documentation/locking/lockdep-design.rst.
1306
1307config PROVE_RAW_LOCK_NESTING
1308	bool "Enable raw_spinlock - spinlock nesting checks"
1309	depends on PROVE_LOCKING
1310	default n
1311	help
1312	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1313	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1314	 not violated.
1315
1316	 NOTE: There are known nesting problems. So if you enable this
1317	 option expect lockdep splats until these problems have been fully
1318	 addressed which is work in progress. This config switch allows to
1319	 identify and analyze these problems. It will be removed and the
1320	 check permanently enabled once the main issues have been fixed.
1321
1322	 If unsure, select N.
1323
1324config LOCK_STAT
1325	bool "Lock usage statistics"
1326	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1327	select LOCKDEP
1328	select DEBUG_SPINLOCK
1329	select DEBUG_MUTEXES if !PREEMPT_RT
1330	select DEBUG_RT_MUTEXES if RT_MUTEXES
1331	select DEBUG_LOCK_ALLOC
1332	default n
1333	help
1334	 This feature enables tracking lock contention points
1335
1336	 For more details, see Documentation/locking/lockstat.rst
1337
1338	 This also enables lock events required by "perf lock",
1339	 subcommand of perf.
1340	 If you want to use "perf lock", you also need to turn on
1341	 CONFIG_EVENT_TRACING.
1342
1343	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1344	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1345
1346config DEBUG_RT_MUTEXES
1347	bool "RT Mutex debugging, deadlock detection"
1348	depends on DEBUG_KERNEL && RT_MUTEXES
1349	help
1350	 This allows rt mutex semantics violations and rt mutex related
1351	 deadlocks (lockups) to be detected and reported automatically.
1352
1353config DEBUG_SPINLOCK
1354	bool "Spinlock and rw-lock debugging: basic checks"
1355	depends on DEBUG_KERNEL
1356	select UNINLINE_SPIN_UNLOCK
1357	help
1358	  Say Y here and build SMP to catch missing spinlock initialization
1359	  and certain other kinds of spinlock errors commonly made.  This is
1360	  best used in conjunction with the NMI watchdog so that spinlock
1361	  deadlocks are also debuggable.
1362
1363config DEBUG_MUTEXES
1364	bool "Mutex debugging: basic checks"
1365	depends on DEBUG_KERNEL && !PREEMPT_RT
1366	help
1367	 This feature allows mutex semantics violations to be detected and
1368	 reported.
1369
1370config DEBUG_WW_MUTEX_SLOWPATH
1371	bool "Wait/wound mutex debugging: Slowpath testing"
1372	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1373	select DEBUG_LOCK_ALLOC
1374	select DEBUG_SPINLOCK
1375	select DEBUG_MUTEXES if !PREEMPT_RT
1376	select DEBUG_RT_MUTEXES if PREEMPT_RT
1377	help
1378	 This feature enables slowpath testing for w/w mutex users by
1379	 injecting additional -EDEADLK wound/backoff cases. Together with
1380	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1381	 will test all possible w/w mutex interface abuse with the
1382	 exception of simply not acquiring all the required locks.
1383	 Note that this feature can introduce significant overhead, so
1384	 it really should not be enabled in a production or distro kernel,
1385	 even a debug kernel.  If you are a driver writer, enable it.  If
1386	 you are a distro, do not.
1387
1388config DEBUG_RWSEMS
1389	bool "RW Semaphore debugging: basic checks"
1390	depends on DEBUG_KERNEL
1391	help
1392	  This debugging feature allows mismatched rw semaphore locks
1393	  and unlocks to be detected and reported.
1394
1395config DEBUG_LOCK_ALLOC
1396	bool "Lock debugging: detect incorrect freeing of live locks"
1397	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1398	select DEBUG_SPINLOCK
1399	select DEBUG_MUTEXES if !PREEMPT_RT
1400	select DEBUG_RT_MUTEXES if RT_MUTEXES
1401	select LOCKDEP
1402	help
1403	 This feature will check whether any held lock (spinlock, rwlock,
1404	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1405	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1406	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1407	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1408	 held during task exit.
1409
1410config LOCKDEP
1411	bool
1412	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1413	select STACKTRACE
1414	select KALLSYMS
1415	select KALLSYMS_ALL
1416
1417config LOCKDEP_SMALL
1418	bool
1419
1420config LOCKDEP_BITS
1421	int "Bitsize for MAX_LOCKDEP_ENTRIES"
1422	depends on LOCKDEP && !LOCKDEP_SMALL
1423	range 10 30
1424	default 15
1425	help
1426	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1427
1428config LOCKDEP_CHAINS_BITS
1429	int "Bitsize for MAX_LOCKDEP_CHAINS"
1430	depends on LOCKDEP && !LOCKDEP_SMALL
1431	range 10 30
1432	default 16
1433	help
1434	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1435
1436config LOCKDEP_STACK_TRACE_BITS
1437	int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1438	depends on LOCKDEP && !LOCKDEP_SMALL
1439	range 10 30
1440	default 19
1441	help
1442	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1443
1444config LOCKDEP_STACK_TRACE_HASH_BITS
1445	int "Bitsize for STACK_TRACE_HASH_SIZE"
1446	depends on LOCKDEP && !LOCKDEP_SMALL
1447	range 10 30
1448	default 14
1449	help
1450	  Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1451
1452config LOCKDEP_CIRCULAR_QUEUE_BITS
1453	int "Bitsize for elements in circular_queue struct"
1454	depends on LOCKDEP
1455	range 10 30
1456	default 12
1457	help
1458	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1459
1460config DEBUG_LOCKDEP
1461	bool "Lock dependency engine debugging"
1462	depends on DEBUG_KERNEL && LOCKDEP
1463	select DEBUG_IRQFLAGS
1464	help
1465	  If you say Y here, the lock dependency engine will do
1466	  additional runtime checks to debug itself, at the price
1467	  of more runtime overhead.
1468
1469config DEBUG_ATOMIC_SLEEP
1470	bool "Sleep inside atomic section checking"
1471	select PREEMPT_COUNT
1472	depends on DEBUG_KERNEL
1473	depends on !ARCH_NO_PREEMPT
1474	help
1475	  If you say Y here, various routines which may sleep will become very
1476	  noisy if they are called inside atomic sections: when a spinlock is
1477	  held, inside an rcu read side critical section, inside preempt disabled
1478	  sections, inside an interrupt, etc...
1479
1480config DEBUG_LOCKING_API_SELFTESTS
1481	bool "Locking API boot-time self-tests"
1482	depends on DEBUG_KERNEL
1483	help
1484	  Say Y here if you want the kernel to run a short self-test during
1485	  bootup. The self-test checks whether common types of locking bugs
1486	  are detected by debugging mechanisms or not. (if you disable
1487	  lock debugging then those bugs won't be detected of course.)
1488	  The following locking APIs are covered: spinlocks, rwlocks,
1489	  mutexes and rwsems.
1490
1491config LOCK_TORTURE_TEST
1492	tristate "torture tests for locking"
1493	depends on DEBUG_KERNEL
1494	select TORTURE_TEST
1495	help
1496	  This option provides a kernel module that runs torture tests
1497	  on kernel locking primitives.  The kernel module may be built
1498	  after the fact on the running kernel to be tested, if desired.
1499
1500	  Say Y here if you want kernel locking-primitive torture tests
1501	  to be built into the kernel.
1502	  Say M if you want these torture tests to build as a module.
1503	  Say N if you are unsure.
1504
1505config WW_MUTEX_SELFTEST
1506	tristate "Wait/wound mutex selftests"
1507	help
1508	  This option provides a kernel module that runs tests on the
1509	  on the struct ww_mutex locking API.
1510
1511	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1512	  with this test harness.
1513
1514	  Say M if you want these self tests to build as a module.
1515	  Say N if you are unsure.
1516
1517config SCF_TORTURE_TEST
1518	tristate "torture tests for smp_call_function*()"
1519	depends on DEBUG_KERNEL
1520	select TORTURE_TEST
1521	help
1522	  This option provides a kernel module that runs torture tests
1523	  on the smp_call_function() family of primitives.  The kernel
1524	  module may be built after the fact on the running kernel to
1525	  be tested, if desired.
1526
1527config CSD_LOCK_WAIT_DEBUG
1528	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1529	depends on DEBUG_KERNEL
1530	depends on 64BIT
1531	default n
1532	help
1533	  This option enables debug prints when CPUs are slow to respond
1534	  to the smp_call_function*() IPI wrappers.  These debug prints
1535	  include the IPI handler function currently executing (if any)
1536	  and relevant stack traces.
1537
1538endmenu # lock debugging
1539
1540config TRACE_IRQFLAGS
1541	depends on TRACE_IRQFLAGS_SUPPORT
1542	bool
1543	help
1544	  Enables hooks to interrupt enabling and disabling for
1545	  either tracing or lock debugging.
1546
1547config TRACE_IRQFLAGS_NMI
1548	def_bool y
1549	depends on TRACE_IRQFLAGS
1550	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1551
1552config DEBUG_IRQFLAGS
1553	bool "Debug IRQ flag manipulation"
1554	help
1555	  Enables checks for potentially unsafe enabling or disabling of
1556	  interrupts, such as calling raw_local_irq_restore() when interrupts
1557	  are enabled.
1558
1559config STACKTRACE
1560	bool "Stack backtrace support"
1561	depends on STACKTRACE_SUPPORT
1562	help
1563	  This option causes the kernel to create a /proc/pid/stack for
1564	  every process, showing its current stack trace.
1565	  It is also used by various kernel debugging features that require
1566	  stack trace generation.
1567
1568config WARN_ALL_UNSEEDED_RANDOM
1569	bool "Warn for all uses of unseeded randomness"
1570	default n
1571	help
1572	  Some parts of the kernel contain bugs relating to their use of
1573	  cryptographically secure random numbers before it's actually possible
1574	  to generate those numbers securely. This setting ensures that these
1575	  flaws don't go unnoticed, by enabling a message, should this ever
1576	  occur. This will allow people with obscure setups to know when things
1577	  are going wrong, so that they might contact developers about fixing
1578	  it.
1579
1580	  Unfortunately, on some models of some architectures getting
1581	  a fully seeded CRNG is extremely difficult, and so this can
1582	  result in dmesg getting spammed for a surprisingly long
1583	  time.  This is really bad from a security perspective, and
1584	  so architecture maintainers really need to do what they can
1585	  to get the CRNG seeded sooner after the system is booted.
1586	  However, since users cannot do anything actionable to
1587	  address this, by default this option is disabled.
1588
1589	  Say Y here if you want to receive warnings for all uses of
1590	  unseeded randomness.  This will be of use primarily for
1591	  those developers interested in improving the security of
1592	  Linux kernels running on their architecture (or
1593	  subarchitecture).
1594
1595config DEBUG_KOBJECT
1596	bool "kobject debugging"
1597	depends on DEBUG_KERNEL
1598	help
1599	  If you say Y here, some extra kobject debugging messages will be sent
1600	  to the syslog.
1601
1602config DEBUG_KOBJECT_RELEASE
1603	bool "kobject release debugging"
1604	depends on DEBUG_OBJECTS_TIMERS
1605	help
1606	  kobjects are reference counted objects.  This means that their
1607	  last reference count put is not predictable, and the kobject can
1608	  live on past the point at which a driver decides to drop its
1609	  initial reference to the kobject gained on allocation.  An
1610	  example of this would be a struct device which has just been
1611	  unregistered.
1612
1613	  However, some buggy drivers assume that after such an operation,
1614	  the memory backing the kobject can be immediately freed.  This
1615	  goes completely against the principles of a refcounted object.
1616
1617	  If you say Y here, the kernel will delay the release of kobjects
1618	  on the last reference count to improve the visibility of this
1619	  kind of kobject release bug.
1620
1621config HAVE_DEBUG_BUGVERBOSE
1622	bool
1623
1624menu "Debug kernel data structures"
1625
1626config DEBUG_LIST
1627	bool "Debug linked list manipulation"
1628	depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1629	help
1630	  Enable this to turn on extended checks in the linked-list
1631	  walking routines.
1632
1633	  If unsure, say N.
1634
1635config DEBUG_PLIST
1636	bool "Debug priority linked list manipulation"
1637	depends on DEBUG_KERNEL
1638	help
1639	  Enable this to turn on extended checks in the priority-ordered
1640	  linked-list (plist) walking routines.  This checks the entire
1641	  list multiple times during each manipulation.
1642
1643	  If unsure, say N.
1644
1645config DEBUG_SG
1646	bool "Debug SG table operations"
1647	depends on DEBUG_KERNEL
1648	help
1649	  Enable this to turn on checks on scatter-gather tables. This can
1650	  help find problems with drivers that do not properly initialize
1651	  their sg tables.
1652
1653	  If unsure, say N.
1654
1655config DEBUG_NOTIFIERS
1656	bool "Debug notifier call chains"
1657	depends on DEBUG_KERNEL
1658	help
1659	  Enable this to turn on sanity checking for notifier call chains.
1660	  This is most useful for kernel developers to make sure that
1661	  modules properly unregister themselves from notifier chains.
1662	  This is a relatively cheap check but if you care about maximum
1663	  performance, say N.
1664
1665config BUG_ON_DATA_CORRUPTION
1666	bool "Trigger a BUG when data corruption is detected"
1667	select DEBUG_LIST
1668	help
1669	  Select this option if the kernel should BUG when it encounters
1670	  data corruption in kernel memory structures when they get checked
1671	  for validity.
1672
1673	  If unsure, say N.
1674
1675config DEBUG_MAPLE_TREE
1676	bool "Debug maple trees"
1677	depends on DEBUG_KERNEL
1678	help
1679	  Enable maple tree debugging information and extra validations.
1680
1681	  If unsure, say N.
1682
1683endmenu
1684
1685config DEBUG_CREDENTIALS
1686	bool "Debug credential management"
1687	depends on DEBUG_KERNEL
1688	help
1689	  Enable this to turn on some debug checking for credential
1690	  management.  The additional code keeps track of the number of
1691	  pointers from task_structs to any given cred struct, and checks to
1692	  see that this number never exceeds the usage count of the cred
1693	  struct.
1694
1695	  Furthermore, if SELinux is enabled, this also checks that the
1696	  security pointer in the cred struct is never seen to be invalid.
1697
1698	  If unsure, say N.
1699
1700source "kernel/rcu/Kconfig.debug"
1701
1702config DEBUG_WQ_FORCE_RR_CPU
1703	bool "Force round-robin CPU selection for unbound work items"
1704	depends on DEBUG_KERNEL
1705	default n
1706	help
1707	  Workqueue used to implicitly guarantee that work items queued
1708	  without explicit CPU specified are put on the local CPU.  This
1709	  guarantee is no longer true and while local CPU is still
1710	  preferred work items may be put on foreign CPUs.  Kernel
1711	  parameter "workqueue.debug_force_rr_cpu" is added to force
1712	  round-robin CPU selection to flush out usages which depend on the
1713	  now broken guarantee.  This config option enables the debug
1714	  feature by default.  When enabled, memory and cache locality will
1715	  be impacted.
1716
1717config CPU_HOTPLUG_STATE_CONTROL
1718	bool "Enable CPU hotplug state control"
1719	depends on DEBUG_KERNEL
1720	depends on HOTPLUG_CPU
1721	default n
1722	help
1723	  Allows to write steps between "offline" and "online" to the CPUs
1724	  sysfs target file so states can be stepped granular. This is a debug
1725	  option for now as the hotplug machinery cannot be stopped and
1726	  restarted at arbitrary points yet.
1727
1728	  Say N if your are unsure.
1729
1730config LATENCYTOP
1731	bool "Latency measuring infrastructure"
1732	depends on DEBUG_KERNEL
1733	depends on STACKTRACE_SUPPORT
1734	depends on PROC_FS
1735	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1736	select KALLSYMS
1737	select KALLSYMS_ALL
1738	select STACKTRACE
1739	select SCHEDSTATS
1740	help
1741	  Enable this option if you want to use the LatencyTOP tool
1742	  to find out which userspace is blocking on what kernel operations.
1743
1744source "kernel/trace/Kconfig"
1745
1746config PROVIDE_OHCI1394_DMA_INIT
1747	bool "Remote debugging over FireWire early on boot"
1748	depends on PCI && X86
1749	help
1750	  If you want to debug problems which hang or crash the kernel early
1751	  on boot and the crashing machine has a FireWire port, you can use
1752	  this feature to remotely access the memory of the crashed machine
1753	  over FireWire. This employs remote DMA as part of the OHCI1394
1754	  specification which is now the standard for FireWire controllers.
1755
1756	  With remote DMA, you can monitor the printk buffer remotely using
1757	  firescope and access all memory below 4GB using fireproxy from gdb.
1758	  Even controlling a kernel debugger is possible using remote DMA.
1759
1760	  Usage:
1761
1762	  If ohci1394_dma=early is used as boot parameter, it will initialize
1763	  all OHCI1394 controllers which are found in the PCI config space.
1764
1765	  As all changes to the FireWire bus such as enabling and disabling
1766	  devices cause a bus reset and thereby disable remote DMA for all
1767	  devices, be sure to have the cable plugged and FireWire enabled on
1768	  the debugging host before booting the debug target for debugging.
1769
1770	  This code (~1k) is freed after boot. By then, the firewire stack
1771	  in charge of the OHCI-1394 controllers should be used instead.
1772
1773	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1774
1775source "samples/Kconfig"
1776
1777config ARCH_HAS_DEVMEM_IS_ALLOWED
1778	bool
1779
1780config STRICT_DEVMEM
1781	bool "Filter access to /dev/mem"
1782	depends on MMU && DEVMEM
1783	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1784	default y if PPC || X86 || ARM64
1785	help
1786	  If this option is disabled, you allow userspace (root) access to all
1787	  of memory, including kernel and userspace memory. Accidental
1788	  access to this is obviously disastrous, but specific access can
1789	  be used by people debugging the kernel. Note that with PAT support
1790	  enabled, even in this case there are restrictions on /dev/mem
1791	  use due to the cache aliasing requirements.
1792
1793	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1794	  file only allows userspace access to PCI space and the BIOS code and
1795	  data regions.  This is sufficient for dosemu and X and all common
1796	  users of /dev/mem.
1797
1798	  If in doubt, say Y.
1799
1800config IO_STRICT_DEVMEM
1801	bool "Filter I/O access to /dev/mem"
1802	depends on STRICT_DEVMEM
1803	help
1804	  If this option is disabled, you allow userspace (root) access to all
1805	  io-memory regardless of whether a driver is actively using that
1806	  range.  Accidental access to this is obviously disastrous, but
1807	  specific access can be used by people debugging kernel drivers.
1808
1809	  If this option is switched on, the /dev/mem file only allows
1810	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1811	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1812	  if the driver using a given range cannot be disabled.
1813
1814	  If in doubt, say Y.
1815
1816menu "$(SRCARCH) Debugging"
1817
1818source "arch/$(SRCARCH)/Kconfig.debug"
1819
1820endmenu
1821
1822menu "Kernel Testing and Coverage"
1823
1824source "lib/kunit/Kconfig"
1825
1826config NOTIFIER_ERROR_INJECTION
1827	tristate "Notifier error injection"
1828	depends on DEBUG_KERNEL
1829	select DEBUG_FS
1830	help
1831	  This option provides the ability to inject artificial errors to
1832	  specified notifier chain callbacks. It is useful to test the error
1833	  handling of notifier call chain failures.
1834
1835	  Say N if unsure.
1836
1837config PM_NOTIFIER_ERROR_INJECT
1838	tristate "PM notifier error injection module"
1839	depends on PM && NOTIFIER_ERROR_INJECTION
1840	default m if PM_DEBUG
1841	help
1842	  This option provides the ability to inject artificial errors to
1843	  PM notifier chain callbacks.  It is controlled through debugfs
1844	  interface /sys/kernel/debug/notifier-error-inject/pm
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	  Example: Inject PM suspend error (-12 = -ENOMEM)
1850
1851	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1852	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1853	  # echo mem > /sys/power/state
1854	  bash: echo: write error: Cannot allocate memory
1855
1856	  To compile this code as a module, choose M here: the module will
1857	  be called pm-notifier-error-inject.
1858
1859	  If unsure, say N.
1860
1861config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1862	tristate "OF reconfig notifier error injection module"
1863	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1864	help
1865	  This option provides the ability to inject artificial errors to
1866	  OF reconfig notifier chain callbacks.  It is controlled
1867	  through debugfs interface under
1868	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1869
1870	  If the notifier call chain should be failed with some events
1871	  notified, write the error code to "actions/<notifier event>/error".
1872
1873	  To compile this code as a module, choose M here: the module will
1874	  be called of-reconfig-notifier-error-inject.
1875
1876	  If unsure, say N.
1877
1878config NETDEV_NOTIFIER_ERROR_INJECT
1879	tristate "Netdev notifier error injection module"
1880	depends on NET && NOTIFIER_ERROR_INJECTION
1881	help
1882	  This option provides the ability to inject artificial errors to
1883	  netdevice notifier chain callbacks.  It is controlled through debugfs
1884	  interface /sys/kernel/debug/notifier-error-inject/netdev
1885
1886	  If the notifier call chain should be failed with some events
1887	  notified, write the error code to "actions/<notifier event>/error".
1888
1889	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
1890
1891	  # cd /sys/kernel/debug/notifier-error-inject/netdev
1892	  # echo -22 > actions/NETDEV_CHANGEMTU/error
1893	  # ip link set eth0 mtu 1024
1894	  RTNETLINK answers: Invalid argument
1895
1896	  To compile this code as a module, choose M here: the module will
1897	  be called netdev-notifier-error-inject.
1898
1899	  If unsure, say N.
1900
1901config FUNCTION_ERROR_INJECTION
1902	def_bool y
1903	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1904
1905config FAULT_INJECTION
1906	bool "Fault-injection framework"
1907	depends on DEBUG_KERNEL
1908	help
1909	  Provide fault-injection framework.
1910	  For more details, see Documentation/fault-injection/.
1911
1912config FAILSLAB
1913	bool "Fault-injection capability for kmalloc"
1914	depends on FAULT_INJECTION
1915	depends on SLAB || SLUB
1916	help
1917	  Provide fault-injection capability for kmalloc.
1918
1919config FAIL_PAGE_ALLOC
1920	bool "Fault-injection capability for alloc_pages()"
1921	depends on FAULT_INJECTION
1922	help
1923	  Provide fault-injection capability for alloc_pages().
1924
1925config FAULT_INJECTION_USERCOPY
1926	bool "Fault injection capability for usercopy functions"
1927	depends on FAULT_INJECTION
1928	help
1929	  Provides fault-injection capability to inject failures
1930	  in usercopy functions (copy_from_user(), get_user(), ...).
1931
1932config FAIL_MAKE_REQUEST
1933	bool "Fault-injection capability for disk IO"
1934	depends on FAULT_INJECTION && BLOCK
1935	help
1936	  Provide fault-injection capability for disk IO.
1937
1938config FAIL_IO_TIMEOUT
1939	bool "Fault-injection capability for faking disk interrupts"
1940	depends on FAULT_INJECTION && BLOCK
1941	help
1942	  Provide fault-injection capability on end IO handling. This
1943	  will make the block layer "forget" an interrupt as configured,
1944	  thus exercising the error handling.
1945
1946	  Only works with drivers that use the generic timeout handling,
1947	  for others it won't do anything.
1948
1949config FAIL_FUTEX
1950	bool "Fault-injection capability for futexes"
1951	select DEBUG_FS
1952	depends on FAULT_INJECTION && FUTEX
1953	help
1954	  Provide fault-injection capability for futexes.
1955
1956config FAULT_INJECTION_DEBUG_FS
1957	bool "Debugfs entries for fault-injection capabilities"
1958	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1959	help
1960	  Enable configuration of fault-injection capabilities via debugfs.
1961
1962config FAIL_FUNCTION
1963	bool "Fault-injection capability for functions"
1964	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1965	help
1966	  Provide function-based fault-injection capability.
1967	  This will allow you to override a specific function with a return
1968	  with given return value. As a result, function caller will see
1969	  an error value and have to handle it. This is useful to test the
1970	  error handling in various subsystems.
1971
1972config FAIL_MMC_REQUEST
1973	bool "Fault-injection capability for MMC IO"
1974	depends on FAULT_INJECTION_DEBUG_FS && MMC
1975	help
1976	  Provide fault-injection capability for MMC IO.
1977	  This will make the mmc core return data errors. This is
1978	  useful to test the error handling in the mmc block device
1979	  and to test how the mmc host driver handles retries from
1980	  the block device.
1981
1982config FAIL_SUNRPC
1983	bool "Fault-injection capability for SunRPC"
1984	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1985	help
1986	  Provide fault-injection capability for SunRPC and
1987	  its consumers.
1988
1989config FAULT_INJECTION_STACKTRACE_FILTER
1990	bool "stacktrace filter for fault-injection capabilities"
1991	depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1992	depends on !X86_64
1993	select STACKTRACE
1994	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1995	help
1996	  Provide stacktrace filter for fault-injection capabilities
1997
1998config ARCH_HAS_KCOV
1999	bool
2000	help
2001	  An architecture should select this when it can successfully
2002	  build and run with CONFIG_KCOV. This typically requires
2003	  disabling instrumentation for some early boot code.
2004
2005config CC_HAS_SANCOV_TRACE_PC
2006	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2007
2008
2009config KCOV
2010	bool "Code coverage for fuzzing"
2011	depends on ARCH_HAS_KCOV
2012	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2013	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2014		   GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2015	select DEBUG_FS
2016	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2017	select OBJTOOL if HAVE_NOINSTR_HACK
2018	help
2019	  KCOV exposes kernel code coverage information in a form suitable
2020	  for coverage-guided fuzzing (randomized testing).
2021
2022	  If RANDOMIZE_BASE is enabled, PC values will not be stable across
2023	  different machines and across reboots. If you need stable PC values,
2024	  disable RANDOMIZE_BASE.
2025
2026	  For more details, see Documentation/dev-tools/kcov.rst.
2027
2028config KCOV_ENABLE_COMPARISONS
2029	bool "Enable comparison operands collection by KCOV"
2030	depends on KCOV
2031	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2032	help
2033	  KCOV also exposes operands of every comparison in the instrumented
2034	  code along with operand sizes and PCs of the comparison instructions.
2035	  These operands can be used by fuzzing engines to improve the quality
2036	  of fuzzing coverage.
2037
2038config KCOV_INSTRUMENT_ALL
2039	bool "Instrument all code by default"
2040	depends on KCOV
2041	default y
2042	help
2043	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2044	  then you will want to instrument the whole kernel and you should
2045	  say y here. If you are doing more targeted fuzzing (like e.g.
2046	  filesystem fuzzing with AFL) then you will want to enable coverage
2047	  for more specific subsets of files, and should say n here.
2048
2049config KCOV_IRQ_AREA_SIZE
2050	hex "Size of interrupt coverage collection area in words"
2051	depends on KCOV
2052	default 0x40000
2053	help
2054	  KCOV uses preallocated per-cpu areas to collect coverage from
2055	  soft interrupts. This specifies the size of those areas in the
2056	  number of unsigned long words.
2057
2058menuconfig RUNTIME_TESTING_MENU
2059	bool "Runtime Testing"
2060	def_bool y
2061
2062if RUNTIME_TESTING_MENU
2063
2064config LKDTM
2065	tristate "Linux Kernel Dump Test Tool Module"
2066	depends on DEBUG_FS
2067	help
2068	This module enables testing of the different dumping mechanisms by
2069	inducing system failures at predefined crash points.
2070	If you don't need it: say N
2071	Choose M here to compile this code as a module. The module will be
2072	called lkdtm.
2073
2074	Documentation on how to use the module can be found in
2075	Documentation/fault-injection/provoke-crashes.rst
2076
2077config CPUMASK_KUNIT_TEST
2078	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2079	depends on KUNIT
2080	default KUNIT_ALL_TESTS
2081	help
2082	  Enable to turn on cpumask tests, running at boot or module load time.
2083
2084	  For more information on KUnit and unit tests in general, please refer
2085	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2086
2087	  If unsure, say N.
2088
2089config TEST_LIST_SORT
2090	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2091	depends on KUNIT
2092	default KUNIT_ALL_TESTS
2093	help
2094	  Enable this to turn on 'list_sort()' function test. This test is
2095	  executed only once during system boot (so affects only boot time),
2096	  or at module load time.
2097
2098	  If unsure, say N.
2099
2100config TEST_MIN_HEAP
2101	tristate "Min heap test"
2102	depends on DEBUG_KERNEL || m
2103	help
2104	  Enable this to turn on min heap function tests. This test is
2105	  executed only once during system boot (so affects only boot time),
2106	  or at module load time.
2107
2108	  If unsure, say N.
2109
2110config TEST_SORT
2111	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2112	depends on KUNIT
2113	default KUNIT_ALL_TESTS
2114	help
2115	  This option enables the self-test function of 'sort()' at boot,
2116	  or at module load time.
2117
2118	  If unsure, say N.
2119
2120config TEST_DIV64
2121	tristate "64bit/32bit division and modulo test"
2122	depends on DEBUG_KERNEL || m
2123	help
2124	  Enable this to turn on 'do_div()' function test. This test is
2125	  executed only once during system boot (so affects only boot time),
2126	  or at module load time.
2127
2128	  If unsure, say N.
2129
2130config KPROBES_SANITY_TEST
2131	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2132	depends on DEBUG_KERNEL
2133	depends on KPROBES
2134	depends on KUNIT
2135	default KUNIT_ALL_TESTS
2136	help
2137	  This option provides for testing basic kprobes functionality on
2138	  boot. Samples of kprobe and kretprobe are inserted and
2139	  verified for functionality.
2140
2141	  Say N if you are unsure.
2142
2143config FPROBE_SANITY_TEST
2144	bool "Self test for fprobe"
2145	depends on DEBUG_KERNEL
2146	depends on FPROBE
2147	depends on KUNIT=y
2148	help
2149	  This option will enable testing the fprobe when the system boot.
2150	  A series of tests are made to verify that the fprobe is functioning
2151	  properly.
2152
2153	  Say N if you are unsure.
2154
2155config BACKTRACE_SELF_TEST
2156	tristate "Self test for the backtrace code"
2157	depends on DEBUG_KERNEL
2158	help
2159	  This option provides a kernel module that can be used to test
2160	  the kernel stack backtrace code. This option is not useful
2161	  for distributions or general kernels, but only for kernel
2162	  developers working on architecture code.
2163
2164	  Note that if you want to also test saved backtraces, you will
2165	  have to enable STACKTRACE as well.
2166
2167	  Say N if you are unsure.
2168
2169config TEST_REF_TRACKER
2170	tristate "Self test for reference tracker"
2171	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2172	select REF_TRACKER
2173	help
2174	  This option provides a kernel module performing tests
2175	  using reference tracker infrastructure.
2176
2177	  Say N if you are unsure.
2178
2179config RBTREE_TEST
2180	tristate "Red-Black tree test"
2181	depends on DEBUG_KERNEL
2182	help
2183	  A benchmark measuring the performance of the rbtree library.
2184	  Also includes rbtree invariant checks.
2185
2186config REED_SOLOMON_TEST
2187	tristate "Reed-Solomon library test"
2188	depends on DEBUG_KERNEL || m
2189	select REED_SOLOMON
2190	select REED_SOLOMON_ENC16
2191	select REED_SOLOMON_DEC16
2192	help
2193	  This option enables the self-test function of rslib at boot,
2194	  or at module load time.
2195
2196	  If unsure, say N.
2197
2198config INTERVAL_TREE_TEST
2199	tristate "Interval tree test"
2200	depends on DEBUG_KERNEL
2201	select INTERVAL_TREE
2202	help
2203	  A benchmark measuring the performance of the interval tree library
2204
2205config PERCPU_TEST
2206	tristate "Per cpu operations test"
2207	depends on m && DEBUG_KERNEL
2208	help
2209	  Enable this option to build test module which validates per-cpu
2210	  operations.
2211
2212	  If unsure, say N.
2213
2214config ATOMIC64_SELFTEST
2215	tristate "Perform an atomic64_t self-test"
2216	help
2217	  Enable this option to test the atomic64_t functions at boot or
2218	  at module load time.
2219
2220	  If unsure, say N.
2221
2222config ASYNC_RAID6_TEST
2223	tristate "Self test for hardware accelerated raid6 recovery"
2224	depends on ASYNC_RAID6_RECOV
2225	select ASYNC_MEMCPY
2226	help
2227	  This is a one-shot self test that permutes through the
2228	  recovery of all the possible two disk failure scenarios for a
2229	  N-disk array.  Recovery is performed with the asynchronous
2230	  raid6 recovery routines, and will optionally use an offload
2231	  engine if one is available.
2232
2233	  If unsure, say N.
2234
2235config TEST_HEXDUMP
2236	tristate "Test functions located in the hexdump module at runtime"
2237
2238config STRING_SELFTEST
2239	tristate "Test string functions at runtime"
2240
2241config TEST_STRING_HELPERS
2242	tristate "Test functions located in the string_helpers module at runtime"
2243
2244config TEST_STRSCPY
2245	tristate "Test strscpy*() family of functions at runtime"
2246
2247config TEST_KSTRTOX
2248	tristate "Test kstrto*() family of functions at runtime"
2249
2250config TEST_PRINTF
2251	tristate "Test printf() family of functions at runtime"
2252
2253config TEST_SCANF
2254	tristate "Test scanf() family of functions at runtime"
2255
2256config TEST_BITMAP
2257	tristate "Test bitmap_*() family of functions at runtime"
2258	help
2259	  Enable this option to test the bitmap functions at boot.
2260
2261	  If unsure, say N.
2262
2263config TEST_UUID
2264	tristate "Test functions located in the uuid module at runtime"
2265
2266config TEST_XARRAY
2267	tristate "Test the XArray code at runtime"
2268
2269config TEST_MAPLE_TREE
2270	select DEBUG_MAPLE_TREE
2271	tristate "Test the Maple Tree code at runtime"
2272
2273config TEST_RHASHTABLE
2274	tristate "Perform selftest on resizable hash table"
2275	help
2276	  Enable this option to test the rhashtable functions at boot.
2277
2278	  If unsure, say N.
2279
2280config TEST_SIPHASH
2281	tristate "Perform selftest on siphash functions"
2282	help
2283	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2284	  functions on boot (or module load).
2285
2286	  This is intended to help people writing architecture-specific
2287	  optimized versions.  If unsure, say N.
2288
2289config TEST_IDA
2290	tristate "Perform selftest on IDA functions"
2291
2292config TEST_PARMAN
2293	tristate "Perform selftest on priority array manager"
2294	depends on PARMAN
2295	help
2296	  Enable this option to test priority array manager on boot
2297	  (or module load).
2298
2299	  If unsure, say N.
2300
2301config TEST_IRQ_TIMINGS
2302	bool "IRQ timings selftest"
2303	depends on IRQ_TIMINGS
2304	help
2305	  Enable this option to test the irq timings code on boot.
2306
2307	  If unsure, say N.
2308
2309config TEST_LKM
2310	tristate "Test module loading with 'hello world' module"
2311	depends on m
2312	help
2313	  This builds the "test_module" module that emits "Hello, world"
2314	  on printk when loaded. It is designed to be used for basic
2315	  evaluation of the module loading subsystem (for example when
2316	  validating module verification). It lacks any extra dependencies,
2317	  and will not normally be loaded by the system unless explicitly
2318	  requested by name.
2319
2320	  If unsure, say N.
2321
2322config TEST_BITOPS
2323	tristate "Test module for compilation of bitops operations"
2324	depends on m
2325	help
2326	  This builds the "test_bitops" module that is much like the
2327	  TEST_LKM module except that it does a basic exercise of the
2328	  set/clear_bit macros and get_count_order/long to make sure there are
2329	  no compiler warnings from C=1 sparse checker or -Wextra
2330	  compilations. It has no dependencies and doesn't run or load unless
2331	  explicitly requested by name.  for example: modprobe test_bitops.
2332
2333	  If unsure, say N.
2334
2335config TEST_VMALLOC
2336	tristate "Test module for stress/performance analysis of vmalloc allocator"
2337	default n
2338       depends on MMU
2339	depends on m
2340	help
2341	  This builds the "test_vmalloc" module that should be used for
2342	  stress and performance analysis. So, any new change for vmalloc
2343	  subsystem can be evaluated from performance and stability point
2344	  of view.
2345
2346	  If unsure, say N.
2347
2348config TEST_USER_COPY
2349	tristate "Test user/kernel boundary protections"
2350	depends on m
2351	help
2352	  This builds the "test_user_copy" module that runs sanity checks
2353	  on the copy_to/from_user infrastructure, making sure basic
2354	  user/kernel boundary testing is working. If it fails to load,
2355	  a regression has been detected in the user/kernel memory boundary
2356	  protections.
2357
2358	  If unsure, say N.
2359
2360config TEST_BPF
2361	tristate "Test BPF filter functionality"
2362	depends on m && NET
2363	help
2364	  This builds the "test_bpf" module that runs various test vectors
2365	  against the BPF interpreter or BPF JIT compiler depending on the
2366	  current setting. This is in particular useful for BPF JIT compiler
2367	  development, but also to run regression tests against changes in
2368	  the interpreter code. It also enables test stubs for eBPF maps and
2369	  verifier used by user space verifier testsuite.
2370
2371	  If unsure, say N.
2372
2373config TEST_BLACKHOLE_DEV
2374	tristate "Test blackhole netdev functionality"
2375	depends on m && NET
2376	help
2377	  This builds the "test_blackhole_dev" module that validates the
2378	  data path through this blackhole netdev.
2379
2380	  If unsure, say N.
2381
2382config FIND_BIT_BENCHMARK
2383	tristate "Test find_bit functions"
2384	help
2385	  This builds the "test_find_bit" module that measure find_*_bit()
2386	  functions performance.
2387
2388	  If unsure, say N.
2389
2390config TEST_FIRMWARE
2391	tristate "Test firmware loading via userspace interface"
2392	depends on FW_LOADER
2393	help
2394	  This builds the "test_firmware" module that creates a userspace
2395	  interface for testing firmware loading. This can be used to
2396	  control the triggering of firmware loading without needing an
2397	  actual firmware-using device. The contents can be rechecked by
2398	  userspace.
2399
2400	  If unsure, say N.
2401
2402config TEST_SYSCTL
2403	tristate "sysctl test driver"
2404	depends on PROC_SYSCTL
2405	help
2406	  This builds the "test_sysctl" module. This driver enables to test the
2407	  proc sysctl interfaces available to drivers safely without affecting
2408	  production knobs which might alter system functionality.
2409
2410	  If unsure, say N.
2411
2412config BITFIELD_KUNIT
2413	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2414	depends on KUNIT
2415	default KUNIT_ALL_TESTS
2416	help
2417	  Enable this option to test the bitfield functions at boot.
2418
2419	  KUnit tests run during boot and output the results to the debug log
2420	  in TAP format (http://testanything.org/). Only useful for kernel devs
2421	  running the KUnit test harness, and not intended for inclusion into a
2422	  production build.
2423
2424	  For more information on KUnit and unit tests in general please refer
2425	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2426
2427	  If unsure, say N.
2428
2429config HASH_KUNIT_TEST
2430	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2431	depends on KUNIT
2432	default KUNIT_ALL_TESTS
2433	help
2434	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2435	  integer (<linux/hash.h>) hash functions on boot.
2436
2437	  KUnit tests run during boot and output the results to the debug log
2438	  in TAP format (https://testanything.org/). Only useful for kernel devs
2439	  running the KUnit test harness, and not intended for inclusion into a
2440	  production build.
2441
2442	  For more information on KUnit and unit tests in general please refer
2443	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2444
2445	  This is intended to help people writing architecture-specific
2446	  optimized versions. If unsure, say N.
2447
2448config RESOURCE_KUNIT_TEST
2449	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2450	depends on KUNIT
2451	default KUNIT_ALL_TESTS
2452	help
2453	  This builds the resource API unit test.
2454	  Tests the logic of API provided by resource.c and ioport.h.
2455	  For more information on KUnit and unit tests in general please refer
2456	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2457
2458	  If unsure, say N.
2459
2460config SYSCTL_KUNIT_TEST
2461	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2462	depends on KUNIT
2463	default KUNIT_ALL_TESTS
2464	help
2465	  This builds the proc sysctl unit test, which runs on boot.
2466	  Tests the API contract and implementation correctness of sysctl.
2467	  For more information on KUnit and unit tests in general please refer
2468	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2469
2470	  If unsure, say N.
2471
2472config LIST_KUNIT_TEST
2473	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2474	depends on KUNIT
2475	default KUNIT_ALL_TESTS
2476	help
2477	  This builds the linked list KUnit test suite.
2478	  It tests that the API and basic functionality of the list_head type
2479	  and associated macros.
2480
2481	  KUnit tests run during boot and output the results to the debug log
2482	  in TAP format (https://testanything.org/). Only useful for kernel devs
2483	  running the KUnit test harness, and not intended for inclusion into a
2484	  production build.
2485
2486	  For more information on KUnit and unit tests in general please refer
2487	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2488
2489	  If unsure, say N.
2490
2491config LINEAR_RANGES_TEST
2492	tristate "KUnit test for linear_ranges"
2493	depends on KUNIT
2494	select LINEAR_RANGES
2495	help
2496	  This builds the linear_ranges unit test, which runs on boot.
2497	  Tests the linear_ranges logic correctness.
2498	  For more information on KUnit and unit tests in general please refer
2499	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2500
2501	  If unsure, say N.
2502
2503config CMDLINE_KUNIT_TEST
2504	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2505	depends on KUNIT
2506	default KUNIT_ALL_TESTS
2507	help
2508	  This builds the cmdline API unit test.
2509	  Tests the logic of API provided by cmdline.c.
2510	  For more information on KUnit and unit tests in general please refer
2511	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2512
2513	  If unsure, say N.
2514
2515config BITS_TEST
2516	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2517	depends on KUNIT
2518	default KUNIT_ALL_TESTS
2519	help
2520	  This builds the bits unit test.
2521	  Tests the logic of macros defined in bits.h.
2522	  For more information on KUnit and unit tests in general please refer
2523	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2524
2525	  If unsure, say N.
2526
2527config SLUB_KUNIT_TEST
2528	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2529	depends on SLUB_DEBUG && KUNIT
2530	default KUNIT_ALL_TESTS
2531	help
2532	  This builds SLUB allocator unit test.
2533	  Tests SLUB cache debugging functionality.
2534	  For more information on KUnit and unit tests in general please refer
2535	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2536
2537	  If unsure, say N.
2538
2539config RATIONAL_KUNIT_TEST
2540	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2541	depends on KUNIT && RATIONAL
2542	default KUNIT_ALL_TESTS
2543	help
2544	  This builds the rational math unit test.
2545	  For more information on KUnit and unit tests in general please refer
2546	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2547
2548	  If unsure, say N.
2549
2550config MEMCPY_KUNIT_TEST
2551	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2552	depends on KUNIT
2553	default KUNIT_ALL_TESTS
2554	help
2555	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2556	  For more information on KUnit and unit tests in general please refer
2557	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2558
2559	  If unsure, say N.
2560
2561config IS_SIGNED_TYPE_KUNIT_TEST
2562	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2563	depends on KUNIT
2564	default KUNIT_ALL_TESTS
2565	help
2566	  Builds unit tests for the is_signed_type() macro.
2567
2568	  For more information on KUnit and unit tests in general please refer
2569	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2570
2571	  If unsure, say N.
2572
2573config OVERFLOW_KUNIT_TEST
2574	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2575	depends on KUNIT
2576	default KUNIT_ALL_TESTS
2577	help
2578	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2579	  related functions.
2580
2581	  For more information on KUnit and unit tests in general please refer
2582	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2583
2584	  If unsure, say N.
2585
2586config STACKINIT_KUNIT_TEST
2587	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2588	depends on KUNIT
2589	default KUNIT_ALL_TESTS
2590	help
2591	  Test if the kernel is zero-initializing stack variables and
2592	  padding. Coverage is controlled by compiler flags,
2593	  CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2594	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2595	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2596
2597config FORTIFY_KUNIT_TEST
2598	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2599	depends on KUNIT && FORTIFY_SOURCE
2600	default KUNIT_ALL_TESTS
2601	help
2602	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2603	  by the str*() and mem*() family of functions. For testing runtime
2604	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2605
2606config HW_BREAKPOINT_KUNIT_TEST
2607	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2608	depends on HAVE_HW_BREAKPOINT
2609	depends on KUNIT=y
2610	default KUNIT_ALL_TESTS
2611	help
2612	  Tests for hw_breakpoint constraints accounting.
2613
2614	  If unsure, say N.
2615
2616config TEST_UDELAY
2617	tristate "udelay test driver"
2618	help
2619	  This builds the "udelay_test" module that helps to make sure
2620	  that udelay() is working properly.
2621
2622	  If unsure, say N.
2623
2624config TEST_STATIC_KEYS
2625	tristate "Test static keys"
2626	depends on m
2627	help
2628	  Test the static key interfaces.
2629
2630	  If unsure, say N.
2631
2632config TEST_DYNAMIC_DEBUG
2633	tristate "Test DYNAMIC_DEBUG"
2634	depends on DYNAMIC_DEBUG
2635	help
2636	  This module registers a tracer callback to count enabled
2637	  pr_debugs in a 'do_debugging' function, then alters their
2638	  enablements, calls the function, and compares counts.
2639
2640	  If unsure, say N.
2641
2642config TEST_KMOD
2643	tristate "kmod stress tester"
2644	depends on m
2645	depends on NETDEVICES && NET_CORE && INET # for TUN
2646	depends on BLOCK
2647	depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2648	select TEST_LKM
2649	select XFS_FS
2650	select TUN
2651	select BTRFS_FS
2652	help
2653	  Test the kernel's module loading mechanism: kmod. kmod implements
2654	  support to load modules using the Linux kernel's usermode helper.
2655	  This test provides a series of tests against kmod.
2656
2657	  Although technically you can either build test_kmod as a module or
2658	  into the kernel we disallow building it into the kernel since
2659	  it stress tests request_module() and this will very likely cause
2660	  some issues by taking over precious threads available from other
2661	  module load requests, ultimately this could be fatal.
2662
2663	  To run tests run:
2664
2665	  tools/testing/selftests/kmod/kmod.sh --help
2666
2667	  If unsure, say N.
2668
2669config TEST_DEBUG_VIRTUAL
2670	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2671	depends on DEBUG_VIRTUAL
2672	help
2673	  Test the kernel's ability to detect incorrect calls to
2674	  virt_to_phys() done against the non-linear part of the
2675	  kernel's virtual address map.
2676
2677	  If unsure, say N.
2678
2679config TEST_MEMCAT_P
2680	tristate "Test memcat_p() helper function"
2681	help
2682	  Test the memcat_p() helper for correctly merging two
2683	  pointer arrays together.
2684
2685	  If unsure, say N.
2686
2687config TEST_LIVEPATCH
2688	tristate "Test livepatching"
2689	default n
2690	depends on DYNAMIC_DEBUG
2691	depends on LIVEPATCH
2692	depends on m
2693	help
2694	  Test kernel livepatching features for correctness.  The tests will
2695	  load test modules that will be livepatched in various scenarios.
2696
2697	  To run all the livepatching tests:
2698
2699	  make -C tools/testing/selftests TARGETS=livepatch run_tests
2700
2701	  Alternatively, individual tests may be invoked:
2702
2703	  tools/testing/selftests/livepatch/test-callbacks.sh
2704	  tools/testing/selftests/livepatch/test-livepatch.sh
2705	  tools/testing/selftests/livepatch/test-shadow-vars.sh
2706
2707	  If unsure, say N.
2708
2709config TEST_OBJAGG
2710	tristate "Perform selftest on object aggreration manager"
2711	default n
2712	depends on OBJAGG
2713	help
2714	  Enable this option to test object aggregation manager on boot
2715	  (or module load).
2716
2717config TEST_MEMINIT
2718	tristate "Test heap/page initialization"
2719	help
2720	  Test if the kernel is zero-initializing heap and page allocations.
2721	  This can be useful to test init_on_alloc and init_on_free features.
2722
2723	  If unsure, say N.
2724
2725config TEST_HMM
2726	tristate "Test HMM (Heterogeneous Memory Management)"
2727	depends on TRANSPARENT_HUGEPAGE
2728	depends on DEVICE_PRIVATE
2729	select HMM_MIRROR
2730	select MMU_NOTIFIER
2731	help
2732	  This is a pseudo device driver solely for testing HMM.
2733	  Say M here if you want to build the HMM test module.
2734	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2735
2736	  If unsure, say N.
2737
2738config TEST_FREE_PAGES
2739	tristate "Test freeing pages"
2740	help
2741	  Test that a memory leak does not occur due to a race between
2742	  freeing a block of pages and a speculative page reference.
2743	  Loading this module is safe if your kernel has the bug fixed.
2744	  If the bug is not fixed, it will leak gigabytes of memory and
2745	  probably OOM your system.
2746
2747config TEST_FPU
2748	tristate "Test floating point operations in kernel space"
2749	depends on X86 && !KCOV_INSTRUMENT_ALL
2750	help
2751	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2752	  which will trigger a sequence of floating point operations. This is used
2753	  for self-testing floating point control register setting in
2754	  kernel_fpu_begin().
2755
2756	  If unsure, say N.
2757
2758config TEST_CLOCKSOURCE_WATCHDOG
2759	tristate "Test clocksource watchdog in kernel space"
2760	depends on CLOCKSOURCE_WATCHDOG
2761	help
2762	  Enable this option to create a kernel module that will trigger
2763	  a test of the clocksource watchdog.  This module may be loaded
2764	  via modprobe or insmod in which case it will run upon being
2765	  loaded, or it may be built in, in which case it will run
2766	  shortly after boot.
2767
2768	  If unsure, say N.
2769
2770endif # RUNTIME_TESTING_MENU
2771
2772config ARCH_USE_MEMTEST
2773	bool
2774	help
2775	  An architecture should select this when it uses early_memtest()
2776	  during boot process.
2777
2778config MEMTEST
2779	bool "Memtest"
2780	depends on ARCH_USE_MEMTEST
2781	help
2782	  This option adds a kernel parameter 'memtest', which allows memtest
2783	  to be set and executed.
2784	        memtest=0, mean disabled; -- default
2785	        memtest=1, mean do 1 test pattern;
2786	        ...
2787	        memtest=17, mean do 17 test patterns.
2788	  If you are unsure how to answer this question, answer N.
2789
2790
2791
2792config HYPERV_TESTING
2793	bool "Microsoft Hyper-V driver testing"
2794	default n
2795	depends on HYPERV && DEBUG_FS
2796	help
2797	  Select this option to enable Hyper-V vmbus testing.
2798
2799endmenu # "Kernel Testing and Coverage"
2800
2801menu "Rust hacking"
2802
2803config RUST_DEBUG_ASSERTIONS
2804	bool "Debug assertions"
2805	depends on RUST
2806	help
2807	  Enables rustc's `-Cdebug-assertions` codegen option.
2808
2809	  This flag lets you turn `cfg(debug_assertions)` conditional
2810	  compilation on or off. This can be used to enable extra debugging
2811	  code in development but not in production. For example, it controls
2812	  the behavior of the standard library's `debug_assert!` macro.
2813
2814	  Note that this will apply to all Rust code, including `core`.
2815
2816	  If unsure, say N.
2817
2818config RUST_OVERFLOW_CHECKS
2819	bool "Overflow checks"
2820	default y
2821	depends on RUST
2822	help
2823	  Enables rustc's `-Coverflow-checks` codegen option.
2824
2825	  This flag allows you to control the behavior of runtime integer
2826	  overflow. When overflow-checks are enabled, a Rust panic will occur
2827	  on overflow.
2828
2829	  Note that this will apply to all Rust code, including `core`.
2830
2831	  If unsure, say Y.
2832
2833endmenu # "Rust"
2834
2835source "Documentation/Kconfig"
2836
2837endmenu # Kernel hacking
2838