xref: /openbmc/linux/lib/Kconfig.debug (revision 6aeadf78)
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 PAHOLE_HAS_LANG_EXCLUDE
393	def_bool PAHOLE_VERSION >= 124
394	help
395	  Support for the --lang_exclude flag which makes pahole exclude
396	  compilation units from the supplied language. Used in Kbuild to
397	  omit Rust CUs which are not supported in version 1.24 of pahole,
398	  otherwise it would emit malformed kernel and module binaries when
399	  using DEBUG_INFO_BTF_MODULES.
400
401config DEBUG_INFO_BTF_MODULES
402	def_bool y
403	depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
404	help
405	  Generate compact split BTF type information for kernel modules.
406
407config MODULE_ALLOW_BTF_MISMATCH
408	bool "Allow loading modules with non-matching BTF type info"
409	depends on DEBUG_INFO_BTF_MODULES
410	help
411	  For modules whose split BTF does not match vmlinux, load without
412	  BTF rather than refusing to load. The default behavior with
413	  module BTF enabled is to reject modules with such mismatches;
414	  this option will still load module BTF where possible but ignore
415	  it when a mismatch is found.
416
417config GDB_SCRIPTS
418	bool "Provide GDB scripts for kernel debugging"
419	help
420	  This creates the required links to GDB helper scripts in the
421	  build directory. If you load vmlinux into gdb, the helper
422	  scripts will be automatically imported by gdb as well, and
423	  additional functions are available to analyze a Linux kernel
424	  instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
425	  for further details.
426
427endif # DEBUG_INFO
428
429config FRAME_WARN
430	int "Warn for stack frames larger than"
431	range 0 8192
432	default 0 if KMSAN
433	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
434	default 2048 if PARISC
435	default 1536 if (!64BIT && XTENSA)
436	default 1280 if KASAN && !64BIT
437	default 1024 if !64BIT
438	default 2048 if 64BIT
439	help
440	  Tell the compiler to warn at build time for stack frames larger than this.
441	  Setting this too low will cause a lot of warnings.
442	  Setting it to 0 disables the warning.
443
444config STRIP_ASM_SYMS
445	bool "Strip assembler-generated symbols during link"
446	default n
447	help
448	  Strip internal assembler-generated symbols during a link (symbols
449	  that look like '.Lxxx') so they don't pollute the output of
450	  get_wchan() and suchlike.
451
452config READABLE_ASM
453	bool "Generate readable assembler code"
454	depends on DEBUG_KERNEL
455	depends on CC_IS_GCC
456	help
457	  Disable some compiler optimizations that tend to generate human unreadable
458	  assembler output. This may make the kernel slightly slower, but it helps
459	  to keep kernel developers who have to stare a lot at assembler listings
460	  sane.
461
462config HEADERS_INSTALL
463	bool "Install uapi headers to usr/include"
464	depends on !UML
465	help
466	  This option will install uapi headers (headers exported to user-space)
467	  into the usr/include directory for use during the kernel build.
468	  This is unneeded for building the kernel itself, but needed for some
469	  user-space program samples. It is also needed by some features such
470	  as uapi header sanity checks.
471
472config DEBUG_SECTION_MISMATCH
473	bool "Enable full Section mismatch analysis"
474	depends on CC_IS_GCC
475	help
476	  The section mismatch analysis checks if there are illegal
477	  references from one section to another section.
478	  During linktime or runtime, some sections are dropped;
479	  any use of code/data previously in these sections would
480	  most likely result in an oops.
481	  In the code, functions and variables are annotated with
482	  __init,, etc. (see the full list in include/linux/init.h),
483	  which results in the code/data being placed in specific sections.
484	  The section mismatch analysis is always performed after a full
485	  kernel build, and enabling this option causes the following
486	  additional step to occur:
487	  - Add the option -fno-inline-functions-called-once to gcc commands.
488	    When inlining a function annotated with __init in a non-init
489	    function, we would lose the section information and thus
490	    the analysis would not catch the illegal reference.
491	    This option tells gcc to inline less (but it does result in
492	    a larger kernel).
493
494config SECTION_MISMATCH_WARN_ONLY
495	bool "Make section mismatch errors non-fatal"
496	default y
497	help
498	  If you say N here, the build process will fail if there are any
499	  section mismatch, instead of just throwing warnings.
500
501	  If unsure, say Y.
502
503config DEBUG_FORCE_FUNCTION_ALIGN_64B
504	bool "Force all function address 64B aligned"
505	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || S390)
506	select FUNCTION_ALIGNMENT_64B
507	help
508	  There are cases that a commit from one domain changes the function
509	  address alignment of other domains, and cause magic performance
510	  bump (regression or improvement). Enable this option will help to
511	  verify if the bump is caused by function alignment changes, while
512	  it will slightly increase the kernel size and affect icache usage.
513
514	  It is mainly for debug and performance tuning use.
515
516#
517# Select this config option from the architecture Kconfig, if it
518# is preferred to always offer frame pointers as a config
519# option on the architecture (regardless of KERNEL_DEBUG):
520#
521config ARCH_WANT_FRAME_POINTERS
522	bool
523
524config FRAME_POINTER
525	bool "Compile the kernel with frame pointers"
526	depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
527	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
528	help
529	  If you say Y here the resulting kernel image will be slightly
530	  larger and slower, but it gives very useful debugging information
531	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
532
533config OBJTOOL
534	bool
535
536config STACK_VALIDATION
537	bool "Compile-time stack metadata validation"
538	depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
539	select OBJTOOL
540	default n
541	help
542	  Validate frame pointer rules at compile-time.  This helps ensure that
543	  runtime stack traces are more reliable.
544
545	  For more information, see
546	  tools/objtool/Documentation/objtool.txt.
547
548config NOINSTR_VALIDATION
549	bool
550	depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
551	select OBJTOOL
552	default y
553
554config VMLINUX_MAP
555	bool "Generate vmlinux.map file when linking"
556	depends on EXPERT
557	help
558	  Selecting this option will pass "-Map=vmlinux.map" to ld
559	  when linking vmlinux. That file can be useful for verifying
560	  and debugging magic section games, and for seeing which
561	  pieces of code get eliminated with
562	  CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
563
564config DEBUG_FORCE_WEAK_PER_CPU
565	bool "Force weak per-cpu definitions"
566	depends on DEBUG_KERNEL
567	help
568	  s390 and alpha require percpu variables in modules to be
569	  defined weak to work around addressing range issue which
570	  puts the following two restrictions on percpu variable
571	  definitions.
572
573	  1. percpu symbols must be unique whether static or not
574	  2. percpu variables can't be defined inside a function
575
576	  To ensure that generic code follows the above rules, this
577	  option forces all percpu variables to be defined as weak.
578
579endmenu # "Compiler options"
580
581menu "Generic Kernel Debugging Instruments"
582
583config MAGIC_SYSRQ
584	bool "Magic SysRq key"
585	depends on !UML
586	help
587	  If you say Y here, you will have some control over the system even
588	  if the system crashes for example during kernel debugging (e.g., you
589	  will be able to flush the buffer cache to disk, reboot the system
590	  immediately or dump some status information). This is accomplished
591	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
592	  also works on a serial console (on PC hardware at least), if you
593	  send a BREAK and then within 5 seconds a command keypress. The
594	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
595	  Don't say Y unless you really know what this hack does.
596
597config MAGIC_SYSRQ_DEFAULT_ENABLE
598	hex "Enable magic SysRq key functions by default"
599	depends on MAGIC_SYSRQ
600	default 0x1
601	help
602	  Specifies which SysRq key functions are enabled by default.
603	  This may be set to 1 or 0 to enable or disable them all, or
604	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
605
606config MAGIC_SYSRQ_SERIAL
607	bool "Enable magic SysRq key over serial"
608	depends on MAGIC_SYSRQ
609	default y
610	help
611	  Many embedded boards have a disconnected TTL level serial which can
612	  generate some garbage that can lead to spurious false sysrq detects.
613	  This option allows you to decide whether you want to enable the
614	  magic SysRq key.
615
616config MAGIC_SYSRQ_SERIAL_SEQUENCE
617	string "Char sequence that enables magic SysRq over serial"
618	depends on MAGIC_SYSRQ_SERIAL
619	default ""
620	help
621	  Specifies a sequence of characters that can follow BREAK to enable
622	  SysRq on a serial console.
623
624	  If unsure, leave an empty string and the option will not be enabled.
625
626config DEBUG_FS
627	bool "Debug Filesystem"
628	help
629	  debugfs is a virtual file system that kernel developers use to put
630	  debugging files into.  Enable this option to be able to read and
631	  write to these files.
632
633	  For detailed documentation on the debugfs API, see
634	  Documentation/filesystems/.
635
636	  If unsure, say N.
637
638choice
639	prompt "Debugfs default access"
640	depends on DEBUG_FS
641	default DEBUG_FS_ALLOW_ALL
642	help
643	  This selects the default access restrictions for debugfs.
644	  It can be overridden with kernel command line option
645	  debugfs=[on,no-mount,off]. The restrictions apply for API access
646	  and filesystem registration.
647
648config DEBUG_FS_ALLOW_ALL
649	bool "Access normal"
650	help
651	  No restrictions apply. Both API and filesystem registration
652	  is on. This is the normal default operation.
653
654config DEBUG_FS_DISALLOW_MOUNT
655	bool "Do not register debugfs as filesystem"
656	help
657	  The API is open but filesystem is not loaded. Clients can still do
658	  their work and read with debug tools that do not need
659	  debugfs filesystem.
660
661config DEBUG_FS_ALLOW_NONE
662	bool "No access"
663	help
664	  Access is off. Clients get -PERM when trying to create nodes in
665	  debugfs tree and debugfs is not registered as a filesystem.
666	  Client can then back-off or continue without debugfs access.
667
668endchoice
669
670source "lib/Kconfig.kgdb"
671source "lib/Kconfig.ubsan"
672source "lib/Kconfig.kcsan"
673
674endmenu
675
676menu "Networking Debugging"
677
678source "net/Kconfig.debug"
679
680endmenu # "Networking Debugging"
681
682menu "Memory Debugging"
683
684source "mm/Kconfig.debug"
685
686config DEBUG_OBJECTS
687	bool "Debug object operations"
688	depends on DEBUG_KERNEL
689	help
690	  If you say Y here, additional code will be inserted into the
691	  kernel to track the life time of various objects and validate
692	  the operations on those objects.
693
694config DEBUG_OBJECTS_SELFTEST
695	bool "Debug objects selftest"
696	depends on DEBUG_OBJECTS
697	help
698	  This enables the selftest of the object debug code.
699
700config DEBUG_OBJECTS_FREE
701	bool "Debug objects in freed memory"
702	depends on DEBUG_OBJECTS
703	help
704	  This enables checks whether a k/v free operation frees an area
705	  which contains an object which has not been deactivated
706	  properly. This can make kmalloc/kfree-intensive workloads
707	  much slower.
708
709config DEBUG_OBJECTS_TIMERS
710	bool "Debug timer objects"
711	depends on DEBUG_OBJECTS
712	help
713	  If you say Y here, additional code will be inserted into the
714	  timer routines to track the life time of timer objects and
715	  validate the timer operations.
716
717config DEBUG_OBJECTS_WORK
718	bool "Debug work objects"
719	depends on DEBUG_OBJECTS
720	help
721	  If you say Y here, additional code will be inserted into the
722	  work queue routines to track the life time of work objects and
723	  validate the work operations.
724
725config DEBUG_OBJECTS_RCU_HEAD
726	bool "Debug RCU callbacks objects"
727	depends on DEBUG_OBJECTS
728	help
729	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
730
731config DEBUG_OBJECTS_PERCPU_COUNTER
732	bool "Debug percpu counter objects"
733	depends on DEBUG_OBJECTS
734	help
735	  If you say Y here, additional code will be inserted into the
736	  percpu counter routines to track the life time of percpu counter
737	  objects and validate the percpu counter operations.
738
739config DEBUG_OBJECTS_ENABLE_DEFAULT
740	int "debug_objects bootup default value (0-1)"
741	range 0 1
742	default "1"
743	depends on DEBUG_OBJECTS
744	help
745	  Debug objects boot parameter default value
746
747config SHRINKER_DEBUG
748	bool "Enable shrinker debugging support"
749	depends on DEBUG_FS
750	help
751	  Say Y to enable the shrinker debugfs interface which provides
752	  visibility into the kernel memory shrinkers subsystem.
753	  Disable it to avoid an extra memory footprint.
754
755config DEBUG_STACK_USAGE
756	bool "Stack utilization instrumentation"
757	depends on DEBUG_KERNEL && !IA64
758	help
759	  Enables the display of the minimum amount of free stack which each
760	  task has ever had available in the sysrq-T and sysrq-P debug output.
761
762	  This option will slow down process creation somewhat.
763
764config SCHED_STACK_END_CHECK
765	bool "Detect stack corruption on calls to schedule()"
766	depends on DEBUG_KERNEL
767	default n
768	help
769	  This option checks for a stack overrun on calls to schedule().
770	  If the stack end location is found to be over written always panic as
771	  the content of the corrupted region can no longer be trusted.
772	  This is to ensure no erroneous behaviour occurs which could result in
773	  data corruption or a sporadic crash at a later stage once the region
774	  is examined. The runtime overhead introduced is minimal.
775
776config ARCH_HAS_DEBUG_VM_PGTABLE
777	bool
778	help
779	  An architecture should select this when it can successfully
780	  build and run DEBUG_VM_PGTABLE.
781
782config DEBUG_VM_IRQSOFF
783	def_bool DEBUG_VM && !PREEMPT_RT
784
785config DEBUG_VM
786	bool "Debug VM"
787	depends on DEBUG_KERNEL
788	help
789	  Enable this to turn on extended checks in the virtual-memory system
790	  that may impact performance.
791
792	  If unsure, say N.
793
794config DEBUG_VM_SHOOT_LAZIES
795	bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
796	depends on DEBUG_VM
797	depends on MMU_LAZY_TLB_SHOOTDOWN
798	help
799	  Enable additional IPIs that ensure lazy tlb mm references are removed
800	  before the mm is freed.
801
802	  If unsure, say N.
803
804config DEBUG_VM_MAPLE_TREE
805	bool "Debug VM maple trees"
806	depends on DEBUG_VM
807	select DEBUG_MAPLE_TREE
808	help
809	  Enable VM maple tree debugging information and extra validations.
810
811	  If unsure, say N.
812
813config DEBUG_VM_RB
814	bool "Debug VM red-black trees"
815	depends on DEBUG_VM
816	help
817	  Enable VM red-black tree debugging information and extra validations.
818
819	  If unsure, say N.
820
821config DEBUG_VM_PGFLAGS
822	bool "Debug page-flags operations"
823	depends on DEBUG_VM
824	help
825	  Enables extra validation on page flags operations.
826
827	  If unsure, say N.
828
829config DEBUG_VM_PGTABLE
830	bool "Debug arch page table for semantics compliance"
831	depends on MMU
832	depends on ARCH_HAS_DEBUG_VM_PGTABLE
833	default y if DEBUG_VM
834	help
835	  This option provides a debug method which can be used to test
836	  architecture page table helper functions on various platforms in
837	  verifying if they comply with expected generic MM semantics. This
838	  will help architecture code in making sure that any changes or
839	  new additions of these helpers still conform to expected
840	  semantics of the generic MM. Platforms will have to opt in for
841	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
842
843	  If unsure, say N.
844
845config ARCH_HAS_DEBUG_VIRTUAL
846	bool
847
848config DEBUG_VIRTUAL
849	bool "Debug VM translations"
850	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
851	help
852	  Enable some costly sanity checks in virtual to page code. This can
853	  catch mistakes with virt_to_page() and friends.
854
855	  If unsure, say N.
856
857config DEBUG_NOMMU_REGIONS
858	bool "Debug the global anon/private NOMMU mapping region tree"
859	depends on DEBUG_KERNEL && !MMU
860	help
861	  This option causes the global tree of anonymous and private mapping
862	  regions to be regularly checked for invalid topology.
863
864config DEBUG_MEMORY_INIT
865	bool "Debug memory initialisation" if EXPERT
866	default !EXPERT
867	help
868	  Enable this for additional checks during memory initialisation.
869	  The sanity checks verify aspects of the VM such as the memory model
870	  and other information provided by the architecture. Verbose
871	  information will be printed at KERN_DEBUG loglevel depending
872	  on the mminit_loglevel= command-line option.
873
874	  If unsure, say Y
875
876config MEMORY_NOTIFIER_ERROR_INJECT
877	tristate "Memory hotplug notifier error injection module"
878	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
879	help
880	  This option provides the ability to inject artificial errors to
881	  memory hotplug notifier chain callbacks.  It is controlled through
882	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
883
884	  If the notifier call chain should be failed with some events
885	  notified, write the error code to "actions/<notifier event>/error".
886
887	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
888
889	  # cd /sys/kernel/debug/notifier-error-inject/memory
890	  # echo -12 > actions/MEM_GOING_OFFLINE/error
891	  # echo offline > /sys/devices/system/memory/memoryXXX/state
892	  bash: echo: write error: Cannot allocate memory
893
894	  To compile this code as a module, choose M here: the module will
895	  be called memory-notifier-error-inject.
896
897	  If unsure, say N.
898
899config DEBUG_PER_CPU_MAPS
900	bool "Debug access to per_cpu maps"
901	depends on DEBUG_KERNEL
902	depends on SMP
903	help
904	  Say Y to verify that the per_cpu map being accessed has
905	  been set up. This adds a fair amount of code to kernel memory
906	  and decreases performance.
907
908	  Say N if unsure.
909
910config DEBUG_KMAP_LOCAL
911	bool "Debug kmap_local temporary mappings"
912	depends on DEBUG_KERNEL && KMAP_LOCAL
913	help
914	  This option enables additional error checking for the kmap_local
915	  infrastructure.  Disable for production use.
916
917config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
918	bool
919
920config DEBUG_KMAP_LOCAL_FORCE_MAP
921	bool "Enforce kmap_local temporary mappings"
922	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
923	select KMAP_LOCAL
924	select DEBUG_KMAP_LOCAL
925	help
926	  This option enforces temporary mappings through the kmap_local
927	  mechanism for non-highmem pages and on non-highmem systems.
928	  Disable this for production systems!
929
930config DEBUG_HIGHMEM
931	bool "Highmem debugging"
932	depends on DEBUG_KERNEL && HIGHMEM
933	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
934	select DEBUG_KMAP_LOCAL
935	help
936	  This option enables additional error checking for high memory
937	  systems.  Disable for production systems.
938
939config HAVE_DEBUG_STACKOVERFLOW
940	bool
941
942config DEBUG_STACKOVERFLOW
943	bool "Check for stack overflows"
944	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
945	help
946	  Say Y here if you want to check for overflows of kernel, IRQ
947	  and exception stacks (if your architecture uses them). This
948	  option will show detailed messages if free stack space drops
949	  below a certain limit.
950
951	  These kinds of bugs usually occur when call-chains in the
952	  kernel get too deep, especially when interrupts are
953	  involved.
954
955	  Use this in cases where you see apparently random memory
956	  corruption, especially if it appears in 'struct thread_info'
957
958	  If in doubt, say "N".
959
960source "lib/Kconfig.kasan"
961source "lib/Kconfig.kfence"
962source "lib/Kconfig.kmsan"
963
964endmenu # "Memory Debugging"
965
966config DEBUG_SHIRQ
967	bool "Debug shared IRQ handlers"
968	depends on DEBUG_KERNEL
969	help
970	  Enable this to generate a spurious interrupt just before a shared
971	  interrupt handler is deregistered (generating one when registering
972	  is currently disabled). Drivers need to handle this correctly. Some
973	  don't and need to be caught.
974
975menu "Debug Oops, Lockups and Hangs"
976
977config PANIC_ON_OOPS
978	bool "Panic on Oops"
979	help
980	  Say Y here to enable the kernel to panic when it oopses. This
981	  has the same effect as setting oops=panic on the kernel command
982	  line.
983
984	  This feature is useful to ensure that the kernel does not do
985	  anything erroneous after an oops which could result in data
986	  corruption or other issues.
987
988	  Say N if unsure.
989
990config PANIC_ON_OOPS_VALUE
991	int
992	range 0 1
993	default 0 if !PANIC_ON_OOPS
994	default 1 if PANIC_ON_OOPS
995
996config PANIC_TIMEOUT
997	int "panic timeout"
998	default 0
999	help
1000	  Set the timeout value (in seconds) until a reboot occurs when
1001	  the kernel panics. If n = 0, then we wait forever. A timeout
1002	  value n > 0 will wait n seconds before rebooting, while a timeout
1003	  value n < 0 will reboot immediately.
1004
1005config LOCKUP_DETECTOR
1006	bool
1007
1008config SOFTLOCKUP_DETECTOR
1009	bool "Detect Soft Lockups"
1010	depends on DEBUG_KERNEL && !S390
1011	select LOCKUP_DETECTOR
1012	help
1013	  Say Y here to enable the kernel to act as a watchdog to detect
1014	  soft lockups.
1015
1016	  Softlockups are bugs that cause the kernel to loop in kernel
1017	  mode for more than 20 seconds, without giving other tasks a
1018	  chance to run.  The current stack trace is displayed upon
1019	  detection and the system will stay locked up.
1020
1021config BOOTPARAM_SOFTLOCKUP_PANIC
1022	bool "Panic (Reboot) On Soft Lockups"
1023	depends on SOFTLOCKUP_DETECTOR
1024	help
1025	  Say Y here to enable the kernel to panic on "soft lockups",
1026	  which are bugs that cause the kernel to loop in kernel
1027	  mode for more than 20 seconds (configurable using the watchdog_thresh
1028	  sysctl), without giving other tasks a chance to run.
1029
1030	  The panic can be used in combination with panic_timeout,
1031	  to cause the system to reboot automatically after a
1032	  lockup has been detected. This feature is useful for
1033	  high-availability systems that have uptime guarantees and
1034	  where a lockup must be resolved ASAP.
1035
1036	  Say N if unsure.
1037
1038config HARDLOCKUP_DETECTOR_PERF
1039	bool
1040	select SOFTLOCKUP_DETECTOR
1041
1042#
1043# Enables a timestamp based low pass filter to compensate for perf based
1044# hard lockup detection which runs too fast due to turbo modes.
1045#
1046config HARDLOCKUP_CHECK_TIMESTAMP
1047	bool
1048
1049#
1050# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1051# lockup detector rather than the perf based detector.
1052#
1053config HARDLOCKUP_DETECTOR
1054	bool "Detect Hard Lockups"
1055	depends on DEBUG_KERNEL && !S390
1056	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1057	select LOCKUP_DETECTOR
1058	select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1059	help
1060	  Say Y here to enable the kernel to act as a watchdog to detect
1061	  hard lockups.
1062
1063	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1064	  for more than 10 seconds, without letting other interrupts have a
1065	  chance to run.  The current stack trace is displayed upon detection
1066	  and the system will stay locked up.
1067
1068config BOOTPARAM_HARDLOCKUP_PANIC
1069	bool "Panic (Reboot) On Hard Lockups"
1070	depends on HARDLOCKUP_DETECTOR
1071	help
1072	  Say Y here to enable the kernel to panic on "hard lockups",
1073	  which are bugs that cause the kernel to loop in kernel
1074	  mode with interrupts disabled for more than 10 seconds (configurable
1075	  using the watchdog_thresh sysctl).
1076
1077	  Say N if unsure.
1078
1079config DETECT_HUNG_TASK
1080	bool "Detect Hung Tasks"
1081	depends on DEBUG_KERNEL
1082	default SOFTLOCKUP_DETECTOR
1083	help
1084	  Say Y here to enable the kernel to detect "hung tasks",
1085	  which are bugs that cause the task to be stuck in
1086	  uninterruptible "D" state indefinitely.
1087
1088	  When a hung task is detected, the kernel will print the
1089	  current stack trace (which you should report), but the
1090	  task will stay in uninterruptible state. If lockdep is
1091	  enabled then all held locks will also be reported. This
1092	  feature has negligible overhead.
1093
1094config DEFAULT_HUNG_TASK_TIMEOUT
1095	int "Default timeout for hung task detection (in seconds)"
1096	depends on DETECT_HUNG_TASK
1097	default 120
1098	help
1099	  This option controls the default timeout (in seconds) used
1100	  to determine when a task has become non-responsive and should
1101	  be considered hung.
1102
1103	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1104	  sysctl or by writing a value to
1105	  /proc/sys/kernel/hung_task_timeout_secs.
1106
1107	  A timeout of 0 disables the check.  The default is two minutes.
1108	  Keeping the default should be fine in most cases.
1109
1110config BOOTPARAM_HUNG_TASK_PANIC
1111	bool "Panic (Reboot) On Hung Tasks"
1112	depends on DETECT_HUNG_TASK
1113	help
1114	  Say Y here to enable the kernel to panic on "hung tasks",
1115	  which are bugs that cause the kernel to leave a task stuck
1116	  in uninterruptible "D" state.
1117
1118	  The panic can be used in combination with panic_timeout,
1119	  to cause the system to reboot automatically after a
1120	  hung task has been detected. This feature is useful for
1121	  high-availability systems that have uptime guarantees and
1122	  where a hung tasks must be resolved ASAP.
1123
1124	  Say N if unsure.
1125
1126config WQ_WATCHDOG
1127	bool "Detect Workqueue Stalls"
1128	depends on DEBUG_KERNEL
1129	help
1130	  Say Y here to enable stall detection on workqueues.  If a
1131	  worker pool doesn't make forward progress on a pending work
1132	  item for over a given amount of time, 30s by default, a
1133	  warning message is printed along with dump of workqueue
1134	  state.  This can be configured through kernel parameter
1135	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1136
1137config WQ_CPU_INTENSIVE_REPORT
1138	bool "Report per-cpu work items which hog CPU for too long"
1139	depends on DEBUG_KERNEL
1140	help
1141	  Say Y here to enable reporting of concurrency-managed per-cpu work
1142	  items that hog CPUs for longer than
1143	  workqueue.cpu_intensive_threshold_us. Workqueue automatically
1144	  detects and excludes them from concurrency management to prevent
1145	  them from stalling other per-cpu work items. Occassional
1146	  triggering may not necessarily indicate a problem. Repeated
1147	  triggering likely indicates that the work item should be switched
1148	  to use an unbound workqueue.
1149
1150config TEST_LOCKUP
1151	tristate "Test module to generate lockups"
1152	depends on m
1153	help
1154	  This builds the "test_lockup" module that helps to make sure
1155	  that watchdogs and lockup detectors are working properly.
1156
1157	  Depending on module parameters it could emulate soft or hard
1158	  lockup, "hung task", or locking arbitrary lock for a long time.
1159	  Also it could generate series of lockups with cooling-down periods.
1160
1161	  If unsure, say N.
1162
1163endmenu # "Debug lockups and hangs"
1164
1165menu "Scheduler Debugging"
1166
1167config SCHED_DEBUG
1168	bool "Collect scheduler debugging info"
1169	depends on DEBUG_KERNEL && DEBUG_FS
1170	default y
1171	help
1172	  If you say Y here, the /sys/kernel/debug/sched file will be provided
1173	  that can help debug the scheduler. The runtime overhead of this
1174	  option is minimal.
1175
1176config SCHED_INFO
1177	bool
1178	default n
1179
1180config SCHEDSTATS
1181	bool "Collect scheduler statistics"
1182	depends on DEBUG_KERNEL && PROC_FS
1183	select SCHED_INFO
1184	help
1185	  If you say Y here, additional code will be inserted into the
1186	  scheduler and related routines to collect statistics about
1187	  scheduler behavior and provide them in /proc/schedstat.  These
1188	  stats may be useful for both tuning and debugging the scheduler
1189	  If you aren't debugging the scheduler or trying to tune a specific
1190	  application, you can say N to avoid the very slight overhead
1191	  this adds.
1192
1193endmenu
1194
1195config DEBUG_TIMEKEEPING
1196	bool "Enable extra timekeeping sanity checking"
1197	help
1198	  This option will enable additional timekeeping sanity checks
1199	  which may be helpful when diagnosing issues where timekeeping
1200	  problems are suspected.
1201
1202	  This may include checks in the timekeeping hotpaths, so this
1203	  option may have a (very small) performance impact to some
1204	  workloads.
1205
1206	  If unsure, say N.
1207
1208config DEBUG_PREEMPT
1209	bool "Debug preemptible kernel"
1210	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1211	help
1212	  If you say Y here then the kernel will use a debug variant of the
1213	  commonly used smp_processor_id() function and will print warnings
1214	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1215	  will detect preemption count underflows.
1216
1217	  This option has potential to introduce high runtime overhead,
1218	  depending on workload as it triggers debugging routines for each
1219	  this_cpu operation. It should only be used for debugging purposes.
1220
1221menu "Lock Debugging (spinlocks, mutexes, etc...)"
1222
1223config LOCK_DEBUGGING_SUPPORT
1224	bool
1225	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1226	default y
1227
1228config PROVE_LOCKING
1229	bool "Lock debugging: prove locking correctness"
1230	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1231	select LOCKDEP
1232	select DEBUG_SPINLOCK
1233	select DEBUG_MUTEXES if !PREEMPT_RT
1234	select DEBUG_RT_MUTEXES if RT_MUTEXES
1235	select DEBUG_RWSEMS
1236	select DEBUG_WW_MUTEX_SLOWPATH
1237	select DEBUG_LOCK_ALLOC
1238	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1239	select TRACE_IRQFLAGS
1240	default n
1241	help
1242	 This feature enables the kernel to prove that all locking
1243	 that occurs in the kernel runtime is mathematically
1244	 correct: that under no circumstance could an arbitrary (and
1245	 not yet triggered) combination of observed locking
1246	 sequences (on an arbitrary number of CPUs, running an
1247	 arbitrary number of tasks and interrupt contexts) cause a
1248	 deadlock.
1249
1250	 In short, this feature enables the kernel to report locking
1251	 related deadlocks before they actually occur.
1252
1253	 The proof does not depend on how hard and complex a
1254	 deadlock scenario would be to trigger: how many
1255	 participant CPUs, tasks and irq-contexts would be needed
1256	 for it to trigger. The proof also does not depend on
1257	 timing: if a race and a resulting deadlock is possible
1258	 theoretically (no matter how unlikely the race scenario
1259	 is), it will be proven so and will immediately be
1260	 reported by the kernel (once the event is observed that
1261	 makes the deadlock theoretically possible).
1262
1263	 If a deadlock is impossible (i.e. the locking rules, as
1264	 observed by the kernel, are mathematically correct), the
1265	 kernel reports nothing.
1266
1267	 NOTE: this feature can also be enabled for rwlocks, mutexes
1268	 and rwsems - in which case all dependencies between these
1269	 different locking variants are observed and mapped too, and
1270	 the proof of observed correctness is also maintained for an
1271	 arbitrary combination of these separate locking variants.
1272
1273	 For more details, see Documentation/locking/lockdep-design.rst.
1274
1275config PROVE_RAW_LOCK_NESTING
1276	bool "Enable raw_spinlock - spinlock nesting checks"
1277	depends on PROVE_LOCKING
1278	default n
1279	help
1280	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1281	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1282	 not violated.
1283
1284	 NOTE: There are known nesting problems. So if you enable this
1285	 option expect lockdep splats until these problems have been fully
1286	 addressed which is work in progress. This config switch allows to
1287	 identify and analyze these problems. It will be removed and the
1288	 check permanently enabled once the main issues have been fixed.
1289
1290	 If unsure, select N.
1291
1292config LOCK_STAT
1293	bool "Lock usage statistics"
1294	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1295	select LOCKDEP
1296	select DEBUG_SPINLOCK
1297	select DEBUG_MUTEXES if !PREEMPT_RT
1298	select DEBUG_RT_MUTEXES if RT_MUTEXES
1299	select DEBUG_LOCK_ALLOC
1300	default n
1301	help
1302	 This feature enables tracking lock contention points
1303
1304	 For more details, see Documentation/locking/lockstat.rst
1305
1306	 This also enables lock events required by "perf lock",
1307	 subcommand of perf.
1308	 If you want to use "perf lock", you also need to turn on
1309	 CONFIG_EVENT_TRACING.
1310
1311	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1312	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1313
1314config DEBUG_RT_MUTEXES
1315	bool "RT Mutex debugging, deadlock detection"
1316	depends on DEBUG_KERNEL && RT_MUTEXES
1317	help
1318	 This allows rt mutex semantics violations and rt mutex related
1319	 deadlocks (lockups) to be detected and reported automatically.
1320
1321config DEBUG_SPINLOCK
1322	bool "Spinlock and rw-lock debugging: basic checks"
1323	depends on DEBUG_KERNEL
1324	select UNINLINE_SPIN_UNLOCK
1325	help
1326	  Say Y here and build SMP to catch missing spinlock initialization
1327	  and certain other kinds of spinlock errors commonly made.  This is
1328	  best used in conjunction with the NMI watchdog so that spinlock
1329	  deadlocks are also debuggable.
1330
1331config DEBUG_MUTEXES
1332	bool "Mutex debugging: basic checks"
1333	depends on DEBUG_KERNEL && !PREEMPT_RT
1334	help
1335	 This feature allows mutex semantics violations to be detected and
1336	 reported.
1337
1338config DEBUG_WW_MUTEX_SLOWPATH
1339	bool "Wait/wound mutex debugging: Slowpath testing"
1340	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1341	select DEBUG_LOCK_ALLOC
1342	select DEBUG_SPINLOCK
1343	select DEBUG_MUTEXES if !PREEMPT_RT
1344	select DEBUG_RT_MUTEXES if PREEMPT_RT
1345	help
1346	 This feature enables slowpath testing for w/w mutex users by
1347	 injecting additional -EDEADLK wound/backoff cases. Together with
1348	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1349	 will test all possible w/w mutex interface abuse with the
1350	 exception of simply not acquiring all the required locks.
1351	 Note that this feature can introduce significant overhead, so
1352	 it really should not be enabled in a production or distro kernel,
1353	 even a debug kernel.  If you are a driver writer, enable it.  If
1354	 you are a distro, do not.
1355
1356config DEBUG_RWSEMS
1357	bool "RW Semaphore debugging: basic checks"
1358	depends on DEBUG_KERNEL
1359	help
1360	  This debugging feature allows mismatched rw semaphore locks
1361	  and unlocks to be detected and reported.
1362
1363config DEBUG_LOCK_ALLOC
1364	bool "Lock debugging: detect incorrect freeing of live locks"
1365	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1366	select DEBUG_SPINLOCK
1367	select DEBUG_MUTEXES if !PREEMPT_RT
1368	select DEBUG_RT_MUTEXES if RT_MUTEXES
1369	select LOCKDEP
1370	help
1371	 This feature will check whether any held lock (spinlock, rwlock,
1372	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1373	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1374	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1375	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1376	 held during task exit.
1377
1378config LOCKDEP
1379	bool
1380	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1381	select STACKTRACE
1382	select KALLSYMS
1383	select KALLSYMS_ALL
1384
1385config LOCKDEP_SMALL
1386	bool
1387
1388config LOCKDEP_BITS
1389	int "Bitsize for MAX_LOCKDEP_ENTRIES"
1390	depends on LOCKDEP && !LOCKDEP_SMALL
1391	range 10 30
1392	default 15
1393	help
1394	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1395
1396config LOCKDEP_CHAINS_BITS
1397	int "Bitsize for MAX_LOCKDEP_CHAINS"
1398	depends on LOCKDEP && !LOCKDEP_SMALL
1399	range 10 30
1400	default 16
1401	help
1402	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1403
1404config LOCKDEP_STACK_TRACE_BITS
1405	int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1406	depends on LOCKDEP && !LOCKDEP_SMALL
1407	range 10 30
1408	default 19
1409	help
1410	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1411
1412config LOCKDEP_STACK_TRACE_HASH_BITS
1413	int "Bitsize for STACK_TRACE_HASH_SIZE"
1414	depends on LOCKDEP && !LOCKDEP_SMALL
1415	range 10 30
1416	default 14
1417	help
1418	  Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1419
1420config LOCKDEP_CIRCULAR_QUEUE_BITS
1421	int "Bitsize for elements in circular_queue struct"
1422	depends on LOCKDEP
1423	range 10 30
1424	default 12
1425	help
1426	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1427
1428config DEBUG_LOCKDEP
1429	bool "Lock dependency engine debugging"
1430	depends on DEBUG_KERNEL && LOCKDEP
1431	select DEBUG_IRQFLAGS
1432	help
1433	  If you say Y here, the lock dependency engine will do
1434	  additional runtime checks to debug itself, at the price
1435	  of more runtime overhead.
1436
1437config DEBUG_ATOMIC_SLEEP
1438	bool "Sleep inside atomic section checking"
1439	select PREEMPT_COUNT
1440	depends on DEBUG_KERNEL
1441	depends on !ARCH_NO_PREEMPT
1442	help
1443	  If you say Y here, various routines which may sleep will become very
1444	  noisy if they are called inside atomic sections: when a spinlock is
1445	  held, inside an rcu read side critical section, inside preempt disabled
1446	  sections, inside an interrupt, etc...
1447
1448config DEBUG_LOCKING_API_SELFTESTS
1449	bool "Locking API boot-time self-tests"
1450	depends on DEBUG_KERNEL
1451	help
1452	  Say Y here if you want the kernel to run a short self-test during
1453	  bootup. The self-test checks whether common types of locking bugs
1454	  are detected by debugging mechanisms or not. (if you disable
1455	  lock debugging then those bugs won't be detected of course.)
1456	  The following locking APIs are covered: spinlocks, rwlocks,
1457	  mutexes and rwsems.
1458
1459config LOCK_TORTURE_TEST
1460	tristate "torture tests for locking"
1461	depends on DEBUG_KERNEL
1462	select TORTURE_TEST
1463	help
1464	  This option provides a kernel module that runs torture tests
1465	  on kernel locking primitives.  The kernel module may be built
1466	  after the fact on the running kernel to be tested, if desired.
1467
1468	  Say Y here if you want kernel locking-primitive torture tests
1469	  to be built into the kernel.
1470	  Say M if you want these torture tests to build as a module.
1471	  Say N if you are unsure.
1472
1473config WW_MUTEX_SELFTEST
1474	tristate "Wait/wound mutex selftests"
1475	help
1476	  This option provides a kernel module that runs tests on the
1477	  on the struct ww_mutex locking API.
1478
1479	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1480	  with this test harness.
1481
1482	  Say M if you want these self tests to build as a module.
1483	  Say N if you are unsure.
1484
1485config SCF_TORTURE_TEST
1486	tristate "torture tests for smp_call_function*()"
1487	depends on DEBUG_KERNEL
1488	select TORTURE_TEST
1489	help
1490	  This option provides a kernel module that runs torture tests
1491	  on the smp_call_function() family of primitives.  The kernel
1492	  module may be built after the fact on the running kernel to
1493	  be tested, if desired.
1494
1495config CSD_LOCK_WAIT_DEBUG
1496	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1497	depends on DEBUG_KERNEL
1498	depends on 64BIT
1499	default n
1500	help
1501	  This option enables debug prints when CPUs are slow to respond
1502	  to the smp_call_function*() IPI wrappers.  These debug prints
1503	  include the IPI handler function currently executing (if any)
1504	  and relevant stack traces.
1505
1506config CSD_LOCK_WAIT_DEBUG_DEFAULT
1507	bool "Default csd_lock_wait() debugging on at boot time"
1508	depends on CSD_LOCK_WAIT_DEBUG
1509	depends on 64BIT
1510	default n
1511	help
1512	  This option causes the csdlock_debug= kernel boot parameter to
1513	  default to 1 (basic debugging) instead of 0 (no debugging).
1514
1515endmenu # lock debugging
1516
1517config TRACE_IRQFLAGS
1518	depends on TRACE_IRQFLAGS_SUPPORT
1519	bool
1520	help
1521	  Enables hooks to interrupt enabling and disabling for
1522	  either tracing or lock debugging.
1523
1524config TRACE_IRQFLAGS_NMI
1525	def_bool y
1526	depends on TRACE_IRQFLAGS
1527	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1528
1529config NMI_CHECK_CPU
1530	bool "Debugging for CPUs failing to respond to backtrace requests"
1531	depends on DEBUG_KERNEL
1532	depends on X86
1533	default n
1534	help
1535	  Enables debug prints when a CPU fails to respond to a given
1536	  backtrace NMI.  These prints provide some reasons why a CPU
1537	  might legitimately be failing to respond, for example, if it
1538	  is offline of if ignore_nmis is set.
1539
1540config DEBUG_IRQFLAGS
1541	bool "Debug IRQ flag manipulation"
1542	help
1543	  Enables checks for potentially unsafe enabling or disabling of
1544	  interrupts, such as calling raw_local_irq_restore() when interrupts
1545	  are enabled.
1546
1547config STACKTRACE
1548	bool "Stack backtrace support"
1549	depends on STACKTRACE_SUPPORT
1550	help
1551	  This option causes the kernel to create a /proc/pid/stack for
1552	  every process, showing its current stack trace.
1553	  It is also used by various kernel debugging features that require
1554	  stack trace generation.
1555
1556config WARN_ALL_UNSEEDED_RANDOM
1557	bool "Warn for all uses of unseeded randomness"
1558	default n
1559	help
1560	  Some parts of the kernel contain bugs relating to their use of
1561	  cryptographically secure random numbers before it's actually possible
1562	  to generate those numbers securely. This setting ensures that these
1563	  flaws don't go unnoticed, by enabling a message, should this ever
1564	  occur. This will allow people with obscure setups to know when things
1565	  are going wrong, so that they might contact developers about fixing
1566	  it.
1567
1568	  Unfortunately, on some models of some architectures getting
1569	  a fully seeded CRNG is extremely difficult, and so this can
1570	  result in dmesg getting spammed for a surprisingly long
1571	  time.  This is really bad from a security perspective, and
1572	  so architecture maintainers really need to do what they can
1573	  to get the CRNG seeded sooner after the system is booted.
1574	  However, since users cannot do anything actionable to
1575	  address this, by default this option is disabled.
1576
1577	  Say Y here if you want to receive warnings for all uses of
1578	  unseeded randomness.  This will be of use primarily for
1579	  those developers interested in improving the security of
1580	  Linux kernels running on their architecture (or
1581	  subarchitecture).
1582
1583config DEBUG_KOBJECT
1584	bool "kobject debugging"
1585	depends on DEBUG_KERNEL
1586	help
1587	  If you say Y here, some extra kobject debugging messages will be sent
1588	  to the syslog.
1589
1590config DEBUG_KOBJECT_RELEASE
1591	bool "kobject release debugging"
1592	depends on DEBUG_OBJECTS_TIMERS
1593	help
1594	  kobjects are reference counted objects.  This means that their
1595	  last reference count put is not predictable, and the kobject can
1596	  live on past the point at which a driver decides to drop its
1597	  initial reference to the kobject gained on allocation.  An
1598	  example of this would be a struct device which has just been
1599	  unregistered.
1600
1601	  However, some buggy drivers assume that after such an operation,
1602	  the memory backing the kobject can be immediately freed.  This
1603	  goes completely against the principles of a refcounted object.
1604
1605	  If you say Y here, the kernel will delay the release of kobjects
1606	  on the last reference count to improve the visibility of this
1607	  kind of kobject release bug.
1608
1609config HAVE_DEBUG_BUGVERBOSE
1610	bool
1611
1612menu "Debug kernel data structures"
1613
1614config DEBUG_LIST
1615	bool "Debug linked list manipulation"
1616	depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1617	help
1618	  Enable this to turn on extended checks in the linked-list
1619	  walking routines.
1620
1621	  If unsure, say N.
1622
1623config DEBUG_PLIST
1624	bool "Debug priority linked list manipulation"
1625	depends on DEBUG_KERNEL
1626	help
1627	  Enable this to turn on extended checks in the priority-ordered
1628	  linked-list (plist) walking routines.  This checks the entire
1629	  list multiple times during each manipulation.
1630
1631	  If unsure, say N.
1632
1633config DEBUG_SG
1634	bool "Debug SG table operations"
1635	depends on DEBUG_KERNEL
1636	help
1637	  Enable this to turn on checks on scatter-gather tables. This can
1638	  help find problems with drivers that do not properly initialize
1639	  their sg tables.
1640
1641	  If unsure, say N.
1642
1643config DEBUG_NOTIFIERS
1644	bool "Debug notifier call chains"
1645	depends on DEBUG_KERNEL
1646	help
1647	  Enable this to turn on sanity checking for notifier call chains.
1648	  This is most useful for kernel developers to make sure that
1649	  modules properly unregister themselves from notifier chains.
1650	  This is a relatively cheap check but if you care about maximum
1651	  performance, say N.
1652
1653config BUG_ON_DATA_CORRUPTION
1654	bool "Trigger a BUG when data corruption is detected"
1655	select DEBUG_LIST
1656	help
1657	  Select this option if the kernel should BUG when it encounters
1658	  data corruption in kernel memory structures when they get checked
1659	  for validity.
1660
1661	  If unsure, say N.
1662
1663config DEBUG_MAPLE_TREE
1664	bool "Debug maple trees"
1665	depends on DEBUG_KERNEL
1666	help
1667	  Enable maple tree debugging information and extra validations.
1668
1669	  If unsure, say N.
1670
1671endmenu
1672
1673config DEBUG_CREDENTIALS
1674	bool "Debug credential management"
1675	depends on DEBUG_KERNEL
1676	help
1677	  Enable this to turn on some debug checking for credential
1678	  management.  The additional code keeps track of the number of
1679	  pointers from task_structs to any given cred struct, and checks to
1680	  see that this number never exceeds the usage count of the cred
1681	  struct.
1682
1683	  Furthermore, if SELinux is enabled, this also checks that the
1684	  security pointer in the cred struct is never seen to be invalid.
1685
1686	  If unsure, say N.
1687
1688source "kernel/rcu/Kconfig.debug"
1689
1690config DEBUG_WQ_FORCE_RR_CPU
1691	bool "Force round-robin CPU selection for unbound work items"
1692	depends on DEBUG_KERNEL
1693	default n
1694	help
1695	  Workqueue used to implicitly guarantee that work items queued
1696	  without explicit CPU specified are put on the local CPU.  This
1697	  guarantee is no longer true and while local CPU is still
1698	  preferred work items may be put on foreign CPUs.  Kernel
1699	  parameter "workqueue.debug_force_rr_cpu" is added to force
1700	  round-robin CPU selection to flush out usages which depend on the
1701	  now broken guarantee.  This config option enables the debug
1702	  feature by default.  When enabled, memory and cache locality will
1703	  be impacted.
1704
1705config CPU_HOTPLUG_STATE_CONTROL
1706	bool "Enable CPU hotplug state control"
1707	depends on DEBUG_KERNEL
1708	depends on HOTPLUG_CPU
1709	default n
1710	help
1711	  Allows to write steps between "offline" and "online" to the CPUs
1712	  sysfs target file so states can be stepped granular. This is a debug
1713	  option for now as the hotplug machinery cannot be stopped and
1714	  restarted at arbitrary points yet.
1715
1716	  Say N if your are unsure.
1717
1718config LATENCYTOP
1719	bool "Latency measuring infrastructure"
1720	depends on DEBUG_KERNEL
1721	depends on STACKTRACE_SUPPORT
1722	depends on PROC_FS
1723	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1724	select KALLSYMS
1725	select KALLSYMS_ALL
1726	select STACKTRACE
1727	select SCHEDSTATS
1728	help
1729	  Enable this option if you want to use the LatencyTOP tool
1730	  to find out which userspace is blocking on what kernel operations.
1731
1732config DEBUG_CGROUP_REF
1733	bool "Disable inlining of cgroup css reference count functions"
1734	depends on DEBUG_KERNEL
1735	depends on CGROUPS
1736	depends on KPROBES
1737	default n
1738	help
1739	  Force cgroup css reference count functions to not be inlined so
1740	  that they can be kprobed for debugging.
1741
1742source "kernel/trace/Kconfig"
1743
1744config PROVIDE_OHCI1394_DMA_INIT
1745	bool "Remote debugging over FireWire early on boot"
1746	depends on PCI && X86
1747	help
1748	  If you want to debug problems which hang or crash the kernel early
1749	  on boot and the crashing machine has a FireWire port, you can use
1750	  this feature to remotely access the memory of the crashed machine
1751	  over FireWire. This employs remote DMA as part of the OHCI1394
1752	  specification which is now the standard for FireWire controllers.
1753
1754	  With remote DMA, you can monitor the printk buffer remotely using
1755	  firescope and access all memory below 4GB using fireproxy from gdb.
1756	  Even controlling a kernel debugger is possible using remote DMA.
1757
1758	  Usage:
1759
1760	  If ohci1394_dma=early is used as boot parameter, it will initialize
1761	  all OHCI1394 controllers which are found in the PCI config space.
1762
1763	  As all changes to the FireWire bus such as enabling and disabling
1764	  devices cause a bus reset and thereby disable remote DMA for all
1765	  devices, be sure to have the cable plugged and FireWire enabled on
1766	  the debugging host before booting the debug target for debugging.
1767
1768	  This code (~1k) is freed after boot. By then, the firewire stack
1769	  in charge of the OHCI-1394 controllers should be used instead.
1770
1771	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1772
1773source "samples/Kconfig"
1774
1775config ARCH_HAS_DEVMEM_IS_ALLOWED
1776	bool
1777
1778config STRICT_DEVMEM
1779	bool "Filter access to /dev/mem"
1780	depends on MMU && DEVMEM
1781	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1782	default y if PPC || X86 || ARM64
1783	help
1784	  If this option is disabled, you allow userspace (root) access to all
1785	  of memory, including kernel and userspace memory. Accidental
1786	  access to this is obviously disastrous, but specific access can
1787	  be used by people debugging the kernel. Note that with PAT support
1788	  enabled, even in this case there are restrictions on /dev/mem
1789	  use due to the cache aliasing requirements.
1790
1791	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1792	  file only allows userspace access to PCI space and the BIOS code and
1793	  data regions.  This is sufficient for dosemu and X and all common
1794	  users of /dev/mem.
1795
1796	  If in doubt, say Y.
1797
1798config IO_STRICT_DEVMEM
1799	bool "Filter I/O access to /dev/mem"
1800	depends on STRICT_DEVMEM
1801	help
1802	  If this option is disabled, you allow userspace (root) access to all
1803	  io-memory regardless of whether a driver is actively using that
1804	  range.  Accidental access to this is obviously disastrous, but
1805	  specific access can be used by people debugging kernel drivers.
1806
1807	  If this option is switched on, the /dev/mem file only allows
1808	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1809	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1810	  if the driver using a given range cannot be disabled.
1811
1812	  If in doubt, say Y.
1813
1814menu "$(SRCARCH) Debugging"
1815
1816source "arch/$(SRCARCH)/Kconfig.debug"
1817
1818endmenu
1819
1820menu "Kernel Testing and Coverage"
1821
1822source "lib/kunit/Kconfig"
1823
1824config NOTIFIER_ERROR_INJECTION
1825	tristate "Notifier error injection"
1826	depends on DEBUG_KERNEL
1827	select DEBUG_FS
1828	help
1829	  This option provides the ability to inject artificial errors to
1830	  specified notifier chain callbacks. It is useful to test the error
1831	  handling of notifier call chain failures.
1832
1833	  Say N if unsure.
1834
1835config PM_NOTIFIER_ERROR_INJECT
1836	tristate "PM notifier error injection module"
1837	depends on PM && NOTIFIER_ERROR_INJECTION
1838	default m if PM_DEBUG
1839	help
1840	  This option provides the ability to inject artificial errors to
1841	  PM notifier chain callbacks.  It is controlled through debugfs
1842	  interface /sys/kernel/debug/notifier-error-inject/pm
1843
1844	  If the notifier call chain should be failed with some events
1845	  notified, write the error code to "actions/<notifier event>/error".
1846
1847	  Example: Inject PM suspend error (-12 = -ENOMEM)
1848
1849	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1850	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1851	  # echo mem > /sys/power/state
1852	  bash: echo: write error: Cannot allocate memory
1853
1854	  To compile this code as a module, choose M here: the module will
1855	  be called pm-notifier-error-inject.
1856
1857	  If unsure, say N.
1858
1859config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1860	tristate "OF reconfig notifier error injection module"
1861	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1862	help
1863	  This option provides the ability to inject artificial errors to
1864	  OF reconfig notifier chain callbacks.  It is controlled
1865	  through debugfs interface under
1866	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1867
1868	  If the notifier call chain should be failed with some events
1869	  notified, write the error code to "actions/<notifier event>/error".
1870
1871	  To compile this code as a module, choose M here: the module will
1872	  be called of-reconfig-notifier-error-inject.
1873
1874	  If unsure, say N.
1875
1876config NETDEV_NOTIFIER_ERROR_INJECT
1877	tristate "Netdev notifier error injection module"
1878	depends on NET && NOTIFIER_ERROR_INJECTION
1879	help
1880	  This option provides the ability to inject artificial errors to
1881	  netdevice notifier chain callbacks.  It is controlled through debugfs
1882	  interface /sys/kernel/debug/notifier-error-inject/netdev
1883
1884	  If the notifier call chain should be failed with some events
1885	  notified, write the error code to "actions/<notifier event>/error".
1886
1887	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
1888
1889	  # cd /sys/kernel/debug/notifier-error-inject/netdev
1890	  # echo -22 > actions/NETDEV_CHANGEMTU/error
1891	  # ip link set eth0 mtu 1024
1892	  RTNETLINK answers: Invalid argument
1893
1894	  To compile this code as a module, choose M here: the module will
1895	  be called netdev-notifier-error-inject.
1896
1897	  If unsure, say N.
1898
1899config FUNCTION_ERROR_INJECTION
1900	bool "Fault-injections of functions"
1901	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1902	help
1903	  Add fault injections into various functions that are annotated with
1904	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1905	  value of these functions. This is useful to test error paths of code.
1906
1907	  If unsure, say N
1908
1909config FAULT_INJECTION
1910	bool "Fault-injection framework"
1911	depends on DEBUG_KERNEL
1912	help
1913	  Provide fault-injection framework.
1914	  For more details, see Documentation/fault-injection/.
1915
1916config FAILSLAB
1917	bool "Fault-injection capability for kmalloc"
1918	depends on FAULT_INJECTION
1919	depends on SLAB || SLUB
1920	help
1921	  Provide fault-injection capability for kmalloc.
1922
1923config FAIL_PAGE_ALLOC
1924	bool "Fault-injection capability for alloc_pages()"
1925	depends on FAULT_INJECTION
1926	help
1927	  Provide fault-injection capability for alloc_pages().
1928
1929config FAULT_INJECTION_USERCOPY
1930	bool "Fault injection capability for usercopy functions"
1931	depends on FAULT_INJECTION
1932	help
1933	  Provides fault-injection capability to inject failures
1934	  in usercopy functions (copy_from_user(), get_user(), ...).
1935
1936config FAIL_MAKE_REQUEST
1937	bool "Fault-injection capability for disk IO"
1938	depends on FAULT_INJECTION && BLOCK
1939	help
1940	  Provide fault-injection capability for disk IO.
1941
1942config FAIL_IO_TIMEOUT
1943	bool "Fault-injection capability for faking disk interrupts"
1944	depends on FAULT_INJECTION && BLOCK
1945	help
1946	  Provide fault-injection capability on end IO handling. This
1947	  will make the block layer "forget" an interrupt as configured,
1948	  thus exercising the error handling.
1949
1950	  Only works with drivers that use the generic timeout handling,
1951	  for others it won't do anything.
1952
1953config FAIL_FUTEX
1954	bool "Fault-injection capability for futexes"
1955	select DEBUG_FS
1956	depends on FAULT_INJECTION && FUTEX
1957	help
1958	  Provide fault-injection capability for futexes.
1959
1960config FAULT_INJECTION_DEBUG_FS
1961	bool "Debugfs entries for fault-injection capabilities"
1962	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1963	help
1964	  Enable configuration of fault-injection capabilities via debugfs.
1965
1966config FAIL_FUNCTION
1967	bool "Fault-injection capability for functions"
1968	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1969	help
1970	  Provide function-based fault-injection capability.
1971	  This will allow you to override a specific function with a return
1972	  with given return value. As a result, function caller will see
1973	  an error value and have to handle it. This is useful to test the
1974	  error handling in various subsystems.
1975
1976config FAIL_MMC_REQUEST
1977	bool "Fault-injection capability for MMC IO"
1978	depends on FAULT_INJECTION_DEBUG_FS && MMC
1979	help
1980	  Provide fault-injection capability for MMC IO.
1981	  This will make the mmc core return data errors. This is
1982	  useful to test the error handling in the mmc block device
1983	  and to test how the mmc host driver handles retries from
1984	  the block device.
1985
1986config FAIL_SUNRPC
1987	bool "Fault-injection capability for SunRPC"
1988	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1989	help
1990	  Provide fault-injection capability for SunRPC and
1991	  its consumers.
1992
1993config FAULT_INJECTION_CONFIGFS
1994	bool "Configfs interface for fault-injection capabilities"
1995	depends on FAULT_INJECTION
1996	select CONFIGFS_FS
1997	help
1998	  This option allows configfs-based drivers to dynamically configure
1999	  fault-injection via configfs.  Each parameter for driver-specific
2000	  fault-injection can be made visible as a configfs attribute in a
2001	  configfs group.
2002
2003
2004config FAULT_INJECTION_STACKTRACE_FILTER
2005	bool "stacktrace filter for fault-injection capabilities"
2006	depends on FAULT_INJECTION
2007	depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
2008	select STACKTRACE
2009	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2010	help
2011	  Provide stacktrace filter for fault-injection capabilities
2012
2013config ARCH_HAS_KCOV
2014	bool
2015	help
2016	  An architecture should select this when it can successfully
2017	  build and run with CONFIG_KCOV. This typically requires
2018	  disabling instrumentation for some early boot code.
2019
2020config CC_HAS_SANCOV_TRACE_PC
2021	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2022
2023
2024config KCOV
2025	bool "Code coverage for fuzzing"
2026	depends on ARCH_HAS_KCOV
2027	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2028	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2029		   GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2030	select DEBUG_FS
2031	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2032	select OBJTOOL if HAVE_NOINSTR_HACK
2033	help
2034	  KCOV exposes kernel code coverage information in a form suitable
2035	  for coverage-guided fuzzing (randomized testing).
2036
2037	  If RANDOMIZE_BASE is enabled, PC values will not be stable across
2038	  different machines and across reboots. If you need stable PC values,
2039	  disable RANDOMIZE_BASE.
2040
2041	  For more details, see Documentation/dev-tools/kcov.rst.
2042
2043config KCOV_ENABLE_COMPARISONS
2044	bool "Enable comparison operands collection by KCOV"
2045	depends on KCOV
2046	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2047	help
2048	  KCOV also exposes operands of every comparison in the instrumented
2049	  code along with operand sizes and PCs of the comparison instructions.
2050	  These operands can be used by fuzzing engines to improve the quality
2051	  of fuzzing coverage.
2052
2053config KCOV_INSTRUMENT_ALL
2054	bool "Instrument all code by default"
2055	depends on KCOV
2056	default y
2057	help
2058	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2059	  then you will want to instrument the whole kernel and you should
2060	  say y here. If you are doing more targeted fuzzing (like e.g.
2061	  filesystem fuzzing with AFL) then you will want to enable coverage
2062	  for more specific subsets of files, and should say n here.
2063
2064config KCOV_IRQ_AREA_SIZE
2065	hex "Size of interrupt coverage collection area in words"
2066	depends on KCOV
2067	default 0x40000
2068	help
2069	  KCOV uses preallocated per-cpu areas to collect coverage from
2070	  soft interrupts. This specifies the size of those areas in the
2071	  number of unsigned long words.
2072
2073menuconfig RUNTIME_TESTING_MENU
2074	bool "Runtime Testing"
2075	def_bool y
2076
2077if RUNTIME_TESTING_MENU
2078
2079config TEST_DHRY
2080	tristate "Dhrystone benchmark test"
2081	help
2082	  Enable this to include the Dhrystone 2.1 benchmark.  This test
2083	  calculates the number of Dhrystones per second, and the number of
2084	  DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2085	  by 1757 (the number of Dhrystones per second obtained on the VAX
2086	  11/780, nominally a 1 MIPS machine).
2087
2088	  To run the benchmark, it needs to be enabled explicitly, either from
2089	  the kernel command line (when built-in), or from userspace (when
2090	  built-in or modular.
2091
2092	  Run once during kernel boot:
2093
2094	      test_dhry.run
2095
2096	  Set number of iterations from kernel command line:
2097
2098	      test_dhry.iterations=<n>
2099
2100	  Set number of iterations from userspace:
2101
2102	      echo <n> > /sys/module/test_dhry/parameters/iterations
2103
2104	  Trigger manual run from userspace:
2105
2106	      echo y > /sys/module/test_dhry/parameters/run
2107
2108	  If the number of iterations is <= 0, the test will devise a suitable
2109	  number of iterations (test runs for at least 2s) automatically.
2110	  This process takes ca. 4s.
2111
2112	  If unsure, say N.
2113
2114config LKDTM
2115	tristate "Linux Kernel Dump Test Tool Module"
2116	depends on DEBUG_FS
2117	help
2118	This module enables testing of the different dumping mechanisms by
2119	inducing system failures at predefined crash points.
2120	If you don't need it: say N
2121	Choose M here to compile this code as a module. The module will be
2122	called lkdtm.
2123
2124	Documentation on how to use the module can be found in
2125	Documentation/fault-injection/provoke-crashes.rst
2126
2127config CPUMASK_KUNIT_TEST
2128	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2129	depends on KUNIT
2130	default KUNIT_ALL_TESTS
2131	help
2132	  Enable to turn on cpumask tests, running at boot or module load time.
2133
2134	  For more information on KUnit and unit tests in general, please refer
2135	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2136
2137	  If unsure, say N.
2138
2139config TEST_LIST_SORT
2140	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2141	depends on KUNIT
2142	default KUNIT_ALL_TESTS
2143	help
2144	  Enable this to turn on 'list_sort()' function test. This test is
2145	  executed only once during system boot (so affects only boot time),
2146	  or at module load time.
2147
2148	  If unsure, say N.
2149
2150config TEST_MIN_HEAP
2151	tristate "Min heap test"
2152	depends on DEBUG_KERNEL || m
2153	help
2154	  Enable this to turn on min heap function tests. This test is
2155	  executed only once during system boot (so affects only boot time),
2156	  or at module load time.
2157
2158	  If unsure, say N.
2159
2160config TEST_SORT
2161	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2162	depends on KUNIT
2163	default KUNIT_ALL_TESTS
2164	help
2165	  This option enables the self-test function of 'sort()' at boot,
2166	  or at module load time.
2167
2168	  If unsure, say N.
2169
2170config TEST_DIV64
2171	tristate "64bit/32bit division and modulo test"
2172	depends on DEBUG_KERNEL || m
2173	help
2174	  Enable this to turn on 'do_div()' function test. This test is
2175	  executed only once during system boot (so affects only boot time),
2176	  or at module load time.
2177
2178	  If unsure, say N.
2179
2180config KPROBES_SANITY_TEST
2181	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2182	depends on DEBUG_KERNEL
2183	depends on KPROBES
2184	depends on KUNIT
2185	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2186	default KUNIT_ALL_TESTS
2187	help
2188	  This option provides for testing basic kprobes functionality on
2189	  boot. Samples of kprobe and kretprobe are inserted and
2190	  verified for functionality.
2191
2192	  Say N if you are unsure.
2193
2194config FPROBE_SANITY_TEST
2195	bool "Self test for fprobe"
2196	depends on DEBUG_KERNEL
2197	depends on FPROBE
2198	depends on KUNIT=y
2199	help
2200	  This option will enable testing the fprobe when the system boot.
2201	  A series of tests are made to verify that the fprobe is functioning
2202	  properly.
2203
2204	  Say N if you are unsure.
2205
2206config BACKTRACE_SELF_TEST
2207	tristate "Self test for the backtrace code"
2208	depends on DEBUG_KERNEL
2209	help
2210	  This option provides a kernel module that can be used to test
2211	  the kernel stack backtrace code. This option is not useful
2212	  for distributions or general kernels, but only for kernel
2213	  developers working on architecture code.
2214
2215	  Note that if you want to also test saved backtraces, you will
2216	  have to enable STACKTRACE as well.
2217
2218	  Say N if you are unsure.
2219
2220config TEST_REF_TRACKER
2221	tristate "Self test for reference tracker"
2222	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2223	select REF_TRACKER
2224	help
2225	  This option provides a kernel module performing tests
2226	  using reference tracker infrastructure.
2227
2228	  Say N if you are unsure.
2229
2230config RBTREE_TEST
2231	tristate "Red-Black tree test"
2232	depends on DEBUG_KERNEL
2233	help
2234	  A benchmark measuring the performance of the rbtree library.
2235	  Also includes rbtree invariant checks.
2236
2237config REED_SOLOMON_TEST
2238	tristate "Reed-Solomon library test"
2239	depends on DEBUG_KERNEL || m
2240	select REED_SOLOMON
2241	select REED_SOLOMON_ENC16
2242	select REED_SOLOMON_DEC16
2243	help
2244	  This option enables the self-test function of rslib at boot,
2245	  or at module load time.
2246
2247	  If unsure, say N.
2248
2249config INTERVAL_TREE_TEST
2250	tristate "Interval tree test"
2251	depends on DEBUG_KERNEL
2252	select INTERVAL_TREE
2253	help
2254	  A benchmark measuring the performance of the interval tree library
2255
2256config PERCPU_TEST
2257	tristate "Per cpu operations test"
2258	depends on m && DEBUG_KERNEL
2259	help
2260	  Enable this option to build test module which validates per-cpu
2261	  operations.
2262
2263	  If unsure, say N.
2264
2265config ATOMIC64_SELFTEST
2266	tristate "Perform an atomic64_t self-test"
2267	help
2268	  Enable this option to test the atomic64_t functions at boot or
2269	  at module load time.
2270
2271	  If unsure, say N.
2272
2273config ASYNC_RAID6_TEST
2274	tristate "Self test for hardware accelerated raid6 recovery"
2275	depends on ASYNC_RAID6_RECOV
2276	select ASYNC_MEMCPY
2277	help
2278	  This is a one-shot self test that permutes through the
2279	  recovery of all the possible two disk failure scenarios for a
2280	  N-disk array.  Recovery is performed with the asynchronous
2281	  raid6 recovery routines, and will optionally use an offload
2282	  engine if one is available.
2283
2284	  If unsure, say N.
2285
2286config TEST_HEXDUMP
2287	tristate "Test functions located in the hexdump module at runtime"
2288
2289config STRING_SELFTEST
2290	tristate "Test string functions at runtime"
2291
2292config TEST_STRING_HELPERS
2293	tristate "Test functions located in the string_helpers module at runtime"
2294
2295config TEST_KSTRTOX
2296	tristate "Test kstrto*() family of functions at runtime"
2297
2298config TEST_PRINTF
2299	tristate "Test printf() family of functions at runtime"
2300
2301config TEST_SCANF
2302	tristate "Test scanf() family of functions at runtime"
2303
2304config TEST_BITMAP
2305	tristate "Test bitmap_*() family of functions at runtime"
2306	help
2307	  Enable this option to test the bitmap functions at boot.
2308
2309	  If unsure, say N.
2310
2311config TEST_UUID
2312	tristate "Test functions located in the uuid module at runtime"
2313
2314config TEST_XARRAY
2315	tristate "Test the XArray code at runtime"
2316
2317config TEST_MAPLE_TREE
2318	depends on DEBUG_KERNEL
2319	select DEBUG_MAPLE_TREE
2320	tristate "Test the Maple Tree code at runtime"
2321
2322config TEST_RHASHTABLE
2323	tristate "Perform selftest on resizable hash table"
2324	help
2325	  Enable this option to test the rhashtable functions at boot.
2326
2327	  If unsure, say N.
2328
2329config TEST_IDA
2330	tristate "Perform selftest on IDA functions"
2331
2332config TEST_PARMAN
2333	tristate "Perform selftest on priority array manager"
2334	depends on PARMAN
2335	help
2336	  Enable this option to test priority array manager on boot
2337	  (or module load).
2338
2339	  If unsure, say N.
2340
2341config TEST_IRQ_TIMINGS
2342	bool "IRQ timings selftest"
2343	depends on IRQ_TIMINGS
2344	help
2345	  Enable this option to test the irq timings code on boot.
2346
2347	  If unsure, say N.
2348
2349config TEST_LKM
2350	tristate "Test module loading with 'hello world' module"
2351	depends on m
2352	help
2353	  This builds the "test_module" module that emits "Hello, world"
2354	  on printk when loaded. It is designed to be used for basic
2355	  evaluation of the module loading subsystem (for example when
2356	  validating module verification). It lacks any extra dependencies,
2357	  and will not normally be loaded by the system unless explicitly
2358	  requested by name.
2359
2360	  If unsure, say N.
2361
2362config TEST_BITOPS
2363	tristate "Test module for compilation of bitops operations"
2364	depends on m
2365	help
2366	  This builds the "test_bitops" module that is much like the
2367	  TEST_LKM module except that it does a basic exercise of the
2368	  set/clear_bit macros and get_count_order/long to make sure there are
2369	  no compiler warnings from C=1 sparse checker or -Wextra
2370	  compilations. It has no dependencies and doesn't run or load unless
2371	  explicitly requested by name.  for example: modprobe test_bitops.
2372
2373	  If unsure, say N.
2374
2375config TEST_VMALLOC
2376	tristate "Test module for stress/performance analysis of vmalloc allocator"
2377	default n
2378       depends on MMU
2379	depends on m
2380	help
2381	  This builds the "test_vmalloc" module that should be used for
2382	  stress and performance analysis. So, any new change for vmalloc
2383	  subsystem can be evaluated from performance and stability point
2384	  of view.
2385
2386	  If unsure, say N.
2387
2388config TEST_USER_COPY
2389	tristate "Test user/kernel boundary protections"
2390	depends on m
2391	help
2392	  This builds the "test_user_copy" module that runs sanity checks
2393	  on the copy_to/from_user infrastructure, making sure basic
2394	  user/kernel boundary testing is working. If it fails to load,
2395	  a regression has been detected in the user/kernel memory boundary
2396	  protections.
2397
2398	  If unsure, say N.
2399
2400config TEST_BPF
2401	tristate "Test BPF filter functionality"
2402	depends on m && NET
2403	help
2404	  This builds the "test_bpf" module that runs various test vectors
2405	  against the BPF interpreter or BPF JIT compiler depending on the
2406	  current setting. This is in particular useful for BPF JIT compiler
2407	  development, but also to run regression tests against changes in
2408	  the interpreter code. It also enables test stubs for eBPF maps and
2409	  verifier used by user space verifier testsuite.
2410
2411	  If unsure, say N.
2412
2413config TEST_BLACKHOLE_DEV
2414	tristate "Test blackhole netdev functionality"
2415	depends on m && NET
2416	help
2417	  This builds the "test_blackhole_dev" module that validates the
2418	  data path through this blackhole netdev.
2419
2420	  If unsure, say N.
2421
2422config FIND_BIT_BENCHMARK
2423	tristate "Test find_bit functions"
2424	help
2425	  This builds the "test_find_bit" module that measure find_*_bit()
2426	  functions performance.
2427
2428	  If unsure, say N.
2429
2430config TEST_FIRMWARE
2431	tristate "Test firmware loading via userspace interface"
2432	depends on FW_LOADER
2433	help
2434	  This builds the "test_firmware" module that creates a userspace
2435	  interface for testing firmware loading. This can be used to
2436	  control the triggering of firmware loading without needing an
2437	  actual firmware-using device. The contents can be rechecked by
2438	  userspace.
2439
2440	  If unsure, say N.
2441
2442config TEST_SYSCTL
2443	tristate "sysctl test driver"
2444	depends on PROC_SYSCTL
2445	help
2446	  This builds the "test_sysctl" module. This driver enables to test the
2447	  proc sysctl interfaces available to drivers safely without affecting
2448	  production knobs which might alter system functionality.
2449
2450	  If unsure, say N.
2451
2452config BITFIELD_KUNIT
2453	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2454	depends on KUNIT
2455	default KUNIT_ALL_TESTS
2456	help
2457	  Enable this option to test the bitfield functions at boot.
2458
2459	  KUnit tests run during boot and output the results to the debug log
2460	  in TAP format (http://testanything.org/). Only useful for kernel devs
2461	  running the KUnit test harness, and not intended for inclusion into a
2462	  production build.
2463
2464	  For more information on KUnit and unit tests in general please refer
2465	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2466
2467	  If unsure, say N.
2468
2469config CHECKSUM_KUNIT
2470	tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2471	depends on KUNIT
2472	default KUNIT_ALL_TESTS
2473	help
2474	  Enable this option to test the checksum functions at boot.
2475
2476	  KUnit tests run during boot and output the results to the debug log
2477	  in TAP format (http://testanything.org/). Only useful for kernel devs
2478	  running the KUnit test harness, and not intended for inclusion into a
2479	  production build.
2480
2481	  For more information on KUnit and unit tests in general please refer
2482	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2483
2484	  If unsure, say N.
2485
2486config HASH_KUNIT_TEST
2487	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2488	depends on KUNIT
2489	default KUNIT_ALL_TESTS
2490	help
2491	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2492	  integer (<linux/hash.h>) hash functions on boot.
2493
2494	  KUnit tests run during boot and output the results to the debug log
2495	  in TAP format (https://testanything.org/). Only useful for kernel devs
2496	  running the KUnit test harness, and not intended for inclusion into a
2497	  production build.
2498
2499	  For more information on KUnit and unit tests in general please refer
2500	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2501
2502	  This is intended to help people writing architecture-specific
2503	  optimized versions. If unsure, say N.
2504
2505config RESOURCE_KUNIT_TEST
2506	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2507	depends on KUNIT
2508	default KUNIT_ALL_TESTS
2509	help
2510	  This builds the resource API unit test.
2511	  Tests the logic of API provided by resource.c and ioport.h.
2512	  For more information on KUnit and unit tests in general please refer
2513	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2514
2515	  If unsure, say N.
2516
2517config SYSCTL_KUNIT_TEST
2518	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2519	depends on KUNIT
2520	default KUNIT_ALL_TESTS
2521	help
2522	  This builds the proc sysctl unit test, which runs on boot.
2523	  Tests the API contract and implementation correctness of sysctl.
2524	  For more information on KUnit and unit tests in general please refer
2525	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2526
2527	  If unsure, say N.
2528
2529config LIST_KUNIT_TEST
2530	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2531	depends on KUNIT
2532	default KUNIT_ALL_TESTS
2533	help
2534	  This builds the linked list KUnit test suite.
2535	  It tests that the API and basic functionality of the list_head type
2536	  and associated macros.
2537
2538	  KUnit tests run during boot and output the results to the debug log
2539	  in TAP format (https://testanything.org/). Only useful for kernel devs
2540	  running the KUnit test harness, and not intended for inclusion into a
2541	  production build.
2542
2543	  For more information on KUnit and unit tests in general please refer
2544	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2545
2546	  If unsure, say N.
2547
2548config HASHTABLE_KUNIT_TEST
2549	tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2550	depends on KUNIT
2551	default KUNIT_ALL_TESTS
2552	help
2553	  This builds the hashtable KUnit test suite.
2554	  It tests the basic functionality of the API defined in
2555	  include/linux/hashtable.h. For more information on KUnit and
2556	  unit tests in general please refer to the KUnit documentation
2557	  in Documentation/dev-tools/kunit/.
2558
2559	  If unsure, say N.
2560
2561config LINEAR_RANGES_TEST
2562	tristate "KUnit test for linear_ranges"
2563	depends on KUNIT
2564	select LINEAR_RANGES
2565	help
2566	  This builds the linear_ranges unit test, which runs on boot.
2567	  Tests the linear_ranges logic correctness.
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 CMDLINE_KUNIT_TEST
2574	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2575	depends on KUNIT
2576	default KUNIT_ALL_TESTS
2577	help
2578	  This builds the cmdline API unit test.
2579	  Tests the logic of API provided by cmdline.c.
2580	  For more information on KUnit and unit tests in general please refer
2581	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2582
2583	  If unsure, say N.
2584
2585config BITS_TEST
2586	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2587	depends on KUNIT
2588	default KUNIT_ALL_TESTS
2589	help
2590	  This builds the bits unit test.
2591	  Tests the logic of macros defined in bits.h.
2592	  For more information on KUnit and unit tests in general please refer
2593	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2594
2595	  If unsure, say N.
2596
2597config SLUB_KUNIT_TEST
2598	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2599	depends on SLUB_DEBUG && KUNIT
2600	default KUNIT_ALL_TESTS
2601	help
2602	  This builds SLUB allocator unit test.
2603	  Tests SLUB cache debugging functionality.
2604	  For more information on KUnit and unit tests in general please refer
2605	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2606
2607	  If unsure, say N.
2608
2609config RATIONAL_KUNIT_TEST
2610	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2611	depends on KUNIT && RATIONAL
2612	default KUNIT_ALL_TESTS
2613	help
2614	  This builds the rational math unit test.
2615	  For more information on KUnit and unit tests in general please refer
2616	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2617
2618	  If unsure, say N.
2619
2620config MEMCPY_KUNIT_TEST
2621	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2622	depends on KUNIT
2623	default KUNIT_ALL_TESTS
2624	help
2625	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2626	  For more information on KUnit and unit tests in general please refer
2627	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2628
2629	  If unsure, say N.
2630
2631config MEMCPY_SLOW_KUNIT_TEST
2632	bool "Include exhaustive memcpy tests"
2633	depends on MEMCPY_KUNIT_TEST
2634	default y
2635	help
2636	  Some memcpy tests are quite exhaustive in checking for overlaps
2637	  and bit ranges. These can be very slow, so they are split out
2638	  as a separate config, in case they need to be disabled.
2639
2640config IS_SIGNED_TYPE_KUNIT_TEST
2641	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2642	depends on KUNIT
2643	default KUNIT_ALL_TESTS
2644	help
2645	  Builds unit tests for the is_signed_type() macro.
2646
2647	  For more information on KUnit and unit tests in general please refer
2648	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2649
2650	  If unsure, say N.
2651
2652config OVERFLOW_KUNIT_TEST
2653	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2654	depends on KUNIT
2655	default KUNIT_ALL_TESTS
2656	help
2657	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2658	  related functions.
2659
2660	  For more information on KUnit and unit tests in general please refer
2661	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2662
2663	  If unsure, say N.
2664
2665config STACKINIT_KUNIT_TEST
2666	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2667	depends on KUNIT
2668	default KUNIT_ALL_TESTS
2669	help
2670	  Test if the kernel is zero-initializing stack variables and
2671	  padding. Coverage is controlled by compiler flags,
2672	  CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2673	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2674	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2675
2676config FORTIFY_KUNIT_TEST
2677	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2678	depends on KUNIT
2679	default KUNIT_ALL_TESTS
2680	help
2681	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2682	  by the str*() and mem*() family of functions. For testing runtime
2683	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2684
2685config HW_BREAKPOINT_KUNIT_TEST
2686	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2687	depends on HAVE_HW_BREAKPOINT
2688	depends on KUNIT=y
2689	default KUNIT_ALL_TESTS
2690	help
2691	  Tests for hw_breakpoint constraints accounting.
2692
2693	  If unsure, say N.
2694
2695config STRCAT_KUNIT_TEST
2696	tristate "Test strcat() family of functions at runtime" if !KUNIT_ALL_TESTS
2697	depends on KUNIT
2698	default KUNIT_ALL_TESTS
2699
2700config STRSCPY_KUNIT_TEST
2701	tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2702	depends on KUNIT
2703	default KUNIT_ALL_TESTS
2704
2705config SIPHASH_KUNIT_TEST
2706	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2707	depends on KUNIT
2708	default KUNIT_ALL_TESTS
2709	help
2710	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2711	  functions on boot (or module load).
2712
2713	  This is intended to help people writing architecture-specific
2714	  optimized versions.  If unsure, say N.
2715
2716config TEST_UDELAY
2717	tristate "udelay test driver"
2718	help
2719	  This builds the "udelay_test" module that helps to make sure
2720	  that udelay() is working properly.
2721
2722	  If unsure, say N.
2723
2724config TEST_STATIC_KEYS
2725	tristate "Test static keys"
2726	depends on m
2727	help
2728	  Test the static key interfaces.
2729
2730	  If unsure, say N.
2731
2732config TEST_DYNAMIC_DEBUG
2733	tristate "Test DYNAMIC_DEBUG"
2734	depends on DYNAMIC_DEBUG
2735	help
2736	  This module registers a tracer callback to count enabled
2737	  pr_debugs in a 'do_debugging' function, then alters their
2738	  enablements, calls the function, and compares counts.
2739
2740	  If unsure, say N.
2741
2742config TEST_KMOD
2743	tristate "kmod stress tester"
2744	depends on m
2745	depends on NETDEVICES && NET_CORE && INET # for TUN
2746	depends on BLOCK
2747	depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2748	select TEST_LKM
2749	select XFS_FS
2750	select TUN
2751	select BTRFS_FS
2752	help
2753	  Test the kernel's module loading mechanism: kmod. kmod implements
2754	  support to load modules using the Linux kernel's usermode helper.
2755	  This test provides a series of tests against kmod.
2756
2757	  Although technically you can either build test_kmod as a module or
2758	  into the kernel we disallow building it into the kernel since
2759	  it stress tests request_module() and this will very likely cause
2760	  some issues by taking over precious threads available from other
2761	  module load requests, ultimately this could be fatal.
2762
2763	  To run tests run:
2764
2765	  tools/testing/selftests/kmod/kmod.sh --help
2766
2767	  If unsure, say N.
2768
2769config TEST_DEBUG_VIRTUAL
2770	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2771	depends on DEBUG_VIRTUAL
2772	help
2773	  Test the kernel's ability to detect incorrect calls to
2774	  virt_to_phys() done against the non-linear part of the
2775	  kernel's virtual address map.
2776
2777	  If unsure, say N.
2778
2779config TEST_MEMCAT_P
2780	tristate "Test memcat_p() helper function"
2781	help
2782	  Test the memcat_p() helper for correctly merging two
2783	  pointer arrays together.
2784
2785	  If unsure, say N.
2786
2787config TEST_LIVEPATCH
2788	tristate "Test livepatching"
2789	default n
2790	depends on DYNAMIC_DEBUG
2791	depends on LIVEPATCH
2792	depends on m
2793	help
2794	  Test kernel livepatching features for correctness.  The tests will
2795	  load test modules that will be livepatched in various scenarios.
2796
2797	  To run all the livepatching tests:
2798
2799	  make -C tools/testing/selftests TARGETS=livepatch run_tests
2800
2801	  Alternatively, individual tests may be invoked:
2802
2803	  tools/testing/selftests/livepatch/test-callbacks.sh
2804	  tools/testing/selftests/livepatch/test-livepatch.sh
2805	  tools/testing/selftests/livepatch/test-shadow-vars.sh
2806
2807	  If unsure, say N.
2808
2809config TEST_OBJAGG
2810	tristate "Perform selftest on object aggreration manager"
2811	default n
2812	depends on OBJAGG
2813	help
2814	  Enable this option to test object aggregation manager on boot
2815	  (or module load).
2816
2817config TEST_MEMINIT
2818	tristate "Test heap/page initialization"
2819	help
2820	  Test if the kernel is zero-initializing heap and page allocations.
2821	  This can be useful to test init_on_alloc and init_on_free features.
2822
2823	  If unsure, say N.
2824
2825config TEST_HMM
2826	tristate "Test HMM (Heterogeneous Memory Management)"
2827	depends on TRANSPARENT_HUGEPAGE
2828	depends on DEVICE_PRIVATE
2829	select HMM_MIRROR
2830	select MMU_NOTIFIER
2831	help
2832	  This is a pseudo device driver solely for testing HMM.
2833	  Say M here if you want to build the HMM test module.
2834	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2835
2836	  If unsure, say N.
2837
2838config TEST_FREE_PAGES
2839	tristate "Test freeing pages"
2840	help
2841	  Test that a memory leak does not occur due to a race between
2842	  freeing a block of pages and a speculative page reference.
2843	  Loading this module is safe if your kernel has the bug fixed.
2844	  If the bug is not fixed, it will leak gigabytes of memory and
2845	  probably OOM your system.
2846
2847config TEST_FPU
2848	tristate "Test floating point operations in kernel space"
2849	depends on X86 && !KCOV_INSTRUMENT_ALL
2850	help
2851	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2852	  which will trigger a sequence of floating point operations. This is used
2853	  for self-testing floating point control register setting in
2854	  kernel_fpu_begin().
2855
2856	  If unsure, say N.
2857
2858config TEST_CLOCKSOURCE_WATCHDOG
2859	tristate "Test clocksource watchdog in kernel space"
2860	depends on CLOCKSOURCE_WATCHDOG
2861	help
2862	  Enable this option to create a kernel module that will trigger
2863	  a test of the clocksource watchdog.  This module may be loaded
2864	  via modprobe or insmod in which case it will run upon being
2865	  loaded, or it may be built in, in which case it will run
2866	  shortly after boot.
2867
2868	  If unsure, say N.
2869
2870endif # RUNTIME_TESTING_MENU
2871
2872config ARCH_USE_MEMTEST
2873	bool
2874	help
2875	  An architecture should select this when it uses early_memtest()
2876	  during boot process.
2877
2878config MEMTEST
2879	bool "Memtest"
2880	depends on ARCH_USE_MEMTEST
2881	help
2882	  This option adds a kernel parameter 'memtest', which allows memtest
2883	  to be set and executed.
2884	        memtest=0, mean disabled; -- default
2885	        memtest=1, mean do 1 test pattern;
2886	        ...
2887	        memtest=17, mean do 17 test patterns.
2888	  If you are unsure how to answer this question, answer N.
2889
2890
2891
2892config HYPERV_TESTING
2893	bool "Microsoft Hyper-V driver testing"
2894	default n
2895	depends on HYPERV && DEBUG_FS
2896	help
2897	  Select this option to enable Hyper-V vmbus testing.
2898
2899endmenu # "Kernel Testing and Coverage"
2900
2901menu "Rust hacking"
2902
2903config RUST_DEBUG_ASSERTIONS
2904	bool "Debug assertions"
2905	depends on RUST
2906	help
2907	  Enables rustc's `-Cdebug-assertions` codegen option.
2908
2909	  This flag lets you turn `cfg(debug_assertions)` conditional
2910	  compilation on or off. This can be used to enable extra debugging
2911	  code in development but not in production. For example, it controls
2912	  the behavior of the standard library's `debug_assert!` macro.
2913
2914	  Note that this will apply to all Rust code, including `core`.
2915
2916	  If unsure, say N.
2917
2918config RUST_OVERFLOW_CHECKS
2919	bool "Overflow checks"
2920	default y
2921	depends on RUST
2922	help
2923	  Enables rustc's `-Coverflow-checks` codegen option.
2924
2925	  This flag allows you to control the behavior of runtime integer
2926	  overflow. When overflow-checks are enabled, a Rust panic will occur
2927	  on overflow.
2928
2929	  Note that this will apply to all Rust code, including `core`.
2930
2931	  If unsure, say Y.
2932
2933config RUST_BUILD_ASSERT_ALLOW
2934	bool "Allow unoptimized build-time assertions"
2935	depends on RUST
2936	help
2937	  Controls how are `build_error!` and `build_assert!` handled during build.
2938
2939	  If calls to them exist in the binary, it may indicate a violated invariant
2940	  or that the optimizer failed to verify the invariant during compilation.
2941
2942	  This should not happen, thus by default the build is aborted. However,
2943	  as an escape hatch, you can choose Y here to ignore them during build
2944	  and let the check be carried at runtime (with `panic!` being called if
2945	  the check fails).
2946
2947	  If unsure, say N.
2948
2949endmenu # "Rust"
2950
2951endmenu # Kernel hacking
2952