xref: /openbmc/linux/lib/Kconfig.debug (revision a5961bed)
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 TEST_LOCKUP
1138	tristate "Test module to generate lockups"
1139	depends on m
1140	help
1141	  This builds the "test_lockup" module that helps to make sure
1142	  that watchdogs and lockup detectors are working properly.
1143
1144	  Depending on module parameters it could emulate soft or hard
1145	  lockup, "hung task", or locking arbitrary lock for a long time.
1146	  Also it could generate series of lockups with cooling-down periods.
1147
1148	  If unsure, say N.
1149
1150endmenu # "Debug lockups and hangs"
1151
1152menu "Scheduler Debugging"
1153
1154config SCHED_DEBUG
1155	bool "Collect scheduler debugging info"
1156	depends on DEBUG_KERNEL && DEBUG_FS
1157	default y
1158	help
1159	  If you say Y here, the /sys/kernel/debug/sched file will be provided
1160	  that can help debug the scheduler. The runtime overhead of this
1161	  option is minimal.
1162
1163config SCHED_INFO
1164	bool
1165	default n
1166
1167config SCHEDSTATS
1168	bool "Collect scheduler statistics"
1169	depends on DEBUG_KERNEL && PROC_FS
1170	select SCHED_INFO
1171	help
1172	  If you say Y here, additional code will be inserted into the
1173	  scheduler and related routines to collect statistics about
1174	  scheduler behavior and provide them in /proc/schedstat.  These
1175	  stats may be useful for both tuning and debugging the scheduler
1176	  If you aren't debugging the scheduler or trying to tune a specific
1177	  application, you can say N to avoid the very slight overhead
1178	  this adds.
1179
1180endmenu
1181
1182config DEBUG_TIMEKEEPING
1183	bool "Enable extra timekeeping sanity checking"
1184	help
1185	  This option will enable additional timekeeping sanity checks
1186	  which may be helpful when diagnosing issues where timekeeping
1187	  problems are suspected.
1188
1189	  This may include checks in the timekeeping hotpaths, so this
1190	  option may have a (very small) performance impact to some
1191	  workloads.
1192
1193	  If unsure, say N.
1194
1195config DEBUG_PREEMPT
1196	bool "Debug preemptible kernel"
1197	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1198	help
1199	  If you say Y here then the kernel will use a debug variant of the
1200	  commonly used smp_processor_id() function and will print warnings
1201	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1202	  will detect preemption count underflows.
1203
1204	  This option has potential to introduce high runtime overhead,
1205	  depending on workload as it triggers debugging routines for each
1206	  this_cpu operation. It should only be used for debugging purposes.
1207
1208menu "Lock Debugging (spinlocks, mutexes, etc...)"
1209
1210config LOCK_DEBUGGING_SUPPORT
1211	bool
1212	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1213	default y
1214
1215config PROVE_LOCKING
1216	bool "Lock debugging: prove locking correctness"
1217	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1218	select LOCKDEP
1219	select DEBUG_SPINLOCK
1220	select DEBUG_MUTEXES if !PREEMPT_RT
1221	select DEBUG_RT_MUTEXES if RT_MUTEXES
1222	select DEBUG_RWSEMS
1223	select DEBUG_WW_MUTEX_SLOWPATH
1224	select DEBUG_LOCK_ALLOC
1225	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1226	select TRACE_IRQFLAGS
1227	default n
1228	help
1229	 This feature enables the kernel to prove that all locking
1230	 that occurs in the kernel runtime is mathematically
1231	 correct: that under no circumstance could an arbitrary (and
1232	 not yet triggered) combination of observed locking
1233	 sequences (on an arbitrary number of CPUs, running an
1234	 arbitrary number of tasks and interrupt contexts) cause a
1235	 deadlock.
1236
1237	 In short, this feature enables the kernel to report locking
1238	 related deadlocks before they actually occur.
1239
1240	 The proof does not depend on how hard and complex a
1241	 deadlock scenario would be to trigger: how many
1242	 participant CPUs, tasks and irq-contexts would be needed
1243	 for it to trigger. The proof also does not depend on
1244	 timing: if a race and a resulting deadlock is possible
1245	 theoretically (no matter how unlikely the race scenario
1246	 is), it will be proven so and will immediately be
1247	 reported by the kernel (once the event is observed that
1248	 makes the deadlock theoretically possible).
1249
1250	 If a deadlock is impossible (i.e. the locking rules, as
1251	 observed by the kernel, are mathematically correct), the
1252	 kernel reports nothing.
1253
1254	 NOTE: this feature can also be enabled for rwlocks, mutexes
1255	 and rwsems - in which case all dependencies between these
1256	 different locking variants are observed and mapped too, and
1257	 the proof of observed correctness is also maintained for an
1258	 arbitrary combination of these separate locking variants.
1259
1260	 For more details, see Documentation/locking/lockdep-design.rst.
1261
1262config PROVE_RAW_LOCK_NESTING
1263	bool "Enable raw_spinlock - spinlock nesting checks"
1264	depends on PROVE_LOCKING
1265	default n
1266	help
1267	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1268	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1269	 not violated.
1270
1271	 NOTE: There are known nesting problems. So if you enable this
1272	 option expect lockdep splats until these problems have been fully
1273	 addressed which is work in progress. This config switch allows to
1274	 identify and analyze these problems. It will be removed and the
1275	 check permanently enabled once the main issues have been fixed.
1276
1277	 If unsure, select N.
1278
1279config LOCK_STAT
1280	bool "Lock usage statistics"
1281	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1282	select LOCKDEP
1283	select DEBUG_SPINLOCK
1284	select DEBUG_MUTEXES if !PREEMPT_RT
1285	select DEBUG_RT_MUTEXES if RT_MUTEXES
1286	select DEBUG_LOCK_ALLOC
1287	default n
1288	help
1289	 This feature enables tracking lock contention points
1290
1291	 For more details, see Documentation/locking/lockstat.rst
1292
1293	 This also enables lock events required by "perf lock",
1294	 subcommand of perf.
1295	 If you want to use "perf lock", you also need to turn on
1296	 CONFIG_EVENT_TRACING.
1297
1298	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1299	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1300
1301config DEBUG_RT_MUTEXES
1302	bool "RT Mutex debugging, deadlock detection"
1303	depends on DEBUG_KERNEL && RT_MUTEXES
1304	help
1305	 This allows rt mutex semantics violations and rt mutex related
1306	 deadlocks (lockups) to be detected and reported automatically.
1307
1308config DEBUG_SPINLOCK
1309	bool "Spinlock and rw-lock debugging: basic checks"
1310	depends on DEBUG_KERNEL
1311	select UNINLINE_SPIN_UNLOCK
1312	help
1313	  Say Y here and build SMP to catch missing spinlock initialization
1314	  and certain other kinds of spinlock errors commonly made.  This is
1315	  best used in conjunction with the NMI watchdog so that spinlock
1316	  deadlocks are also debuggable.
1317
1318config DEBUG_MUTEXES
1319	bool "Mutex debugging: basic checks"
1320	depends on DEBUG_KERNEL && !PREEMPT_RT
1321	help
1322	 This feature allows mutex semantics violations to be detected and
1323	 reported.
1324
1325config DEBUG_WW_MUTEX_SLOWPATH
1326	bool "Wait/wound mutex debugging: Slowpath testing"
1327	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1328	select DEBUG_LOCK_ALLOC
1329	select DEBUG_SPINLOCK
1330	select DEBUG_MUTEXES if !PREEMPT_RT
1331	select DEBUG_RT_MUTEXES if PREEMPT_RT
1332	help
1333	 This feature enables slowpath testing for w/w mutex users by
1334	 injecting additional -EDEADLK wound/backoff cases. Together with
1335	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1336	 will test all possible w/w mutex interface abuse with the
1337	 exception of simply not acquiring all the required locks.
1338	 Note that this feature can introduce significant overhead, so
1339	 it really should not be enabled in a production or distro kernel,
1340	 even a debug kernel.  If you are a driver writer, enable it.  If
1341	 you are a distro, do not.
1342
1343config DEBUG_RWSEMS
1344	bool "RW Semaphore debugging: basic checks"
1345	depends on DEBUG_KERNEL
1346	help
1347	  This debugging feature allows mismatched rw semaphore locks
1348	  and unlocks to be detected and reported.
1349
1350config DEBUG_LOCK_ALLOC
1351	bool "Lock debugging: detect incorrect freeing of live locks"
1352	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1353	select DEBUG_SPINLOCK
1354	select DEBUG_MUTEXES if !PREEMPT_RT
1355	select DEBUG_RT_MUTEXES if RT_MUTEXES
1356	select LOCKDEP
1357	help
1358	 This feature will check whether any held lock (spinlock, rwlock,
1359	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1360	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1361	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1362	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1363	 held during task exit.
1364
1365config LOCKDEP
1366	bool
1367	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1368	select STACKTRACE
1369	select KALLSYMS
1370	select KALLSYMS_ALL
1371
1372config LOCKDEP_SMALL
1373	bool
1374
1375config LOCKDEP_BITS
1376	int "Bitsize for MAX_LOCKDEP_ENTRIES"
1377	depends on LOCKDEP && !LOCKDEP_SMALL
1378	range 10 30
1379	default 15
1380	help
1381	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1382
1383config LOCKDEP_CHAINS_BITS
1384	int "Bitsize for MAX_LOCKDEP_CHAINS"
1385	depends on LOCKDEP && !LOCKDEP_SMALL
1386	range 10 30
1387	default 16
1388	help
1389	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1390
1391config LOCKDEP_STACK_TRACE_BITS
1392	int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1393	depends on LOCKDEP && !LOCKDEP_SMALL
1394	range 10 30
1395	default 19
1396	help
1397	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1398
1399config LOCKDEP_STACK_TRACE_HASH_BITS
1400	int "Bitsize for STACK_TRACE_HASH_SIZE"
1401	depends on LOCKDEP && !LOCKDEP_SMALL
1402	range 10 30
1403	default 14
1404	help
1405	  Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1406
1407config LOCKDEP_CIRCULAR_QUEUE_BITS
1408	int "Bitsize for elements in circular_queue struct"
1409	depends on LOCKDEP
1410	range 10 30
1411	default 12
1412	help
1413	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1414
1415config DEBUG_LOCKDEP
1416	bool "Lock dependency engine debugging"
1417	depends on DEBUG_KERNEL && LOCKDEP
1418	select DEBUG_IRQFLAGS
1419	help
1420	  If you say Y here, the lock dependency engine will do
1421	  additional runtime checks to debug itself, at the price
1422	  of more runtime overhead.
1423
1424config DEBUG_ATOMIC_SLEEP
1425	bool "Sleep inside atomic section checking"
1426	select PREEMPT_COUNT
1427	depends on DEBUG_KERNEL
1428	depends on !ARCH_NO_PREEMPT
1429	help
1430	  If you say Y here, various routines which may sleep will become very
1431	  noisy if they are called inside atomic sections: when a spinlock is
1432	  held, inside an rcu read side critical section, inside preempt disabled
1433	  sections, inside an interrupt, etc...
1434
1435config DEBUG_LOCKING_API_SELFTESTS
1436	bool "Locking API boot-time self-tests"
1437	depends on DEBUG_KERNEL
1438	help
1439	  Say Y here if you want the kernel to run a short self-test during
1440	  bootup. The self-test checks whether common types of locking bugs
1441	  are detected by debugging mechanisms or not. (if you disable
1442	  lock debugging then those bugs won't be detected of course.)
1443	  The following locking APIs are covered: spinlocks, rwlocks,
1444	  mutexes and rwsems.
1445
1446config LOCK_TORTURE_TEST
1447	tristate "torture tests for locking"
1448	depends on DEBUG_KERNEL
1449	select TORTURE_TEST
1450	help
1451	  This option provides a kernel module that runs torture tests
1452	  on kernel locking primitives.  The kernel module may be built
1453	  after the fact on the running kernel to be tested, if desired.
1454
1455	  Say Y here if you want kernel locking-primitive torture tests
1456	  to be built into the kernel.
1457	  Say M if you want these torture tests to build as a module.
1458	  Say N if you are unsure.
1459
1460config WW_MUTEX_SELFTEST
1461	tristate "Wait/wound mutex selftests"
1462	help
1463	  This option provides a kernel module that runs tests on the
1464	  on the struct ww_mutex locking API.
1465
1466	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1467	  with this test harness.
1468
1469	  Say M if you want these self tests to build as a module.
1470	  Say N if you are unsure.
1471
1472config SCF_TORTURE_TEST
1473	tristate "torture tests for smp_call_function*()"
1474	depends on DEBUG_KERNEL
1475	select TORTURE_TEST
1476	help
1477	  This option provides a kernel module that runs torture tests
1478	  on the smp_call_function() family of primitives.  The kernel
1479	  module may be built after the fact on the running kernel to
1480	  be tested, if desired.
1481
1482config CSD_LOCK_WAIT_DEBUG
1483	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1484	depends on DEBUG_KERNEL
1485	depends on 64BIT
1486	default n
1487	help
1488	  This option enables debug prints when CPUs are slow to respond
1489	  to the smp_call_function*() IPI wrappers.  These debug prints
1490	  include the IPI handler function currently executing (if any)
1491	  and relevant stack traces.
1492
1493config CSD_LOCK_WAIT_DEBUG_DEFAULT
1494	bool "Default csd_lock_wait() debugging on at boot time"
1495	depends on CSD_LOCK_WAIT_DEBUG
1496	depends on 64BIT
1497	default n
1498	help
1499	  This option causes the csdlock_debug= kernel boot parameter to
1500	  default to 1 (basic debugging) instead of 0 (no debugging).
1501
1502endmenu # lock debugging
1503
1504config TRACE_IRQFLAGS
1505	depends on TRACE_IRQFLAGS_SUPPORT
1506	bool
1507	help
1508	  Enables hooks to interrupt enabling and disabling for
1509	  either tracing or lock debugging.
1510
1511config TRACE_IRQFLAGS_NMI
1512	def_bool y
1513	depends on TRACE_IRQFLAGS
1514	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1515
1516config NMI_CHECK_CPU
1517	bool "Debugging for CPUs failing to respond to backtrace requests"
1518	depends on DEBUG_KERNEL
1519	depends on X86
1520	default n
1521	help
1522	  Enables debug prints when a CPU fails to respond to a given
1523	  backtrace NMI.  These prints provide some reasons why a CPU
1524	  might legitimately be failing to respond, for example, if it
1525	  is offline of if ignore_nmis is set.
1526
1527config DEBUG_IRQFLAGS
1528	bool "Debug IRQ flag manipulation"
1529	help
1530	  Enables checks for potentially unsafe enabling or disabling of
1531	  interrupts, such as calling raw_local_irq_restore() when interrupts
1532	  are enabled.
1533
1534config STACKTRACE
1535	bool "Stack backtrace support"
1536	depends on STACKTRACE_SUPPORT
1537	help
1538	  This option causes the kernel to create a /proc/pid/stack for
1539	  every process, showing its current stack trace.
1540	  It is also used by various kernel debugging features that require
1541	  stack trace generation.
1542
1543config WARN_ALL_UNSEEDED_RANDOM
1544	bool "Warn for all uses of unseeded randomness"
1545	default n
1546	help
1547	  Some parts of the kernel contain bugs relating to their use of
1548	  cryptographically secure random numbers before it's actually possible
1549	  to generate those numbers securely. This setting ensures that these
1550	  flaws don't go unnoticed, by enabling a message, should this ever
1551	  occur. This will allow people with obscure setups to know when things
1552	  are going wrong, so that they might contact developers about fixing
1553	  it.
1554
1555	  Unfortunately, on some models of some architectures getting
1556	  a fully seeded CRNG is extremely difficult, and so this can
1557	  result in dmesg getting spammed for a surprisingly long
1558	  time.  This is really bad from a security perspective, and
1559	  so architecture maintainers really need to do what they can
1560	  to get the CRNG seeded sooner after the system is booted.
1561	  However, since users cannot do anything actionable to
1562	  address this, by default this option is disabled.
1563
1564	  Say Y here if you want to receive warnings for all uses of
1565	  unseeded randomness.  This will be of use primarily for
1566	  those developers interested in improving the security of
1567	  Linux kernels running on their architecture (or
1568	  subarchitecture).
1569
1570config DEBUG_KOBJECT
1571	bool "kobject debugging"
1572	depends on DEBUG_KERNEL
1573	help
1574	  If you say Y here, some extra kobject debugging messages will be sent
1575	  to the syslog.
1576
1577config DEBUG_KOBJECT_RELEASE
1578	bool "kobject release debugging"
1579	depends on DEBUG_OBJECTS_TIMERS
1580	help
1581	  kobjects are reference counted objects.  This means that their
1582	  last reference count put is not predictable, and the kobject can
1583	  live on past the point at which a driver decides to drop its
1584	  initial reference to the kobject gained on allocation.  An
1585	  example of this would be a struct device which has just been
1586	  unregistered.
1587
1588	  However, some buggy drivers assume that after such an operation,
1589	  the memory backing the kobject can be immediately freed.  This
1590	  goes completely against the principles of a refcounted object.
1591
1592	  If you say Y here, the kernel will delay the release of kobjects
1593	  on the last reference count to improve the visibility of this
1594	  kind of kobject release bug.
1595
1596config HAVE_DEBUG_BUGVERBOSE
1597	bool
1598
1599menu "Debug kernel data structures"
1600
1601config DEBUG_LIST
1602	bool "Debug linked list manipulation"
1603	depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1604	help
1605	  Enable this to turn on extended checks in the linked-list
1606	  walking routines.
1607
1608	  If unsure, say N.
1609
1610config DEBUG_PLIST
1611	bool "Debug priority linked list manipulation"
1612	depends on DEBUG_KERNEL
1613	help
1614	  Enable this to turn on extended checks in the priority-ordered
1615	  linked-list (plist) walking routines.  This checks the entire
1616	  list multiple times during each manipulation.
1617
1618	  If unsure, say N.
1619
1620config DEBUG_SG
1621	bool "Debug SG table operations"
1622	depends on DEBUG_KERNEL
1623	help
1624	  Enable this to turn on checks on scatter-gather tables. This can
1625	  help find problems with drivers that do not properly initialize
1626	  their sg tables.
1627
1628	  If unsure, say N.
1629
1630config DEBUG_NOTIFIERS
1631	bool "Debug notifier call chains"
1632	depends on DEBUG_KERNEL
1633	help
1634	  Enable this to turn on sanity checking for notifier call chains.
1635	  This is most useful for kernel developers to make sure that
1636	  modules properly unregister themselves from notifier chains.
1637	  This is a relatively cheap check but if you care about maximum
1638	  performance, say N.
1639
1640config BUG_ON_DATA_CORRUPTION
1641	bool "Trigger a BUG when data corruption is detected"
1642	select DEBUG_LIST
1643	help
1644	  Select this option if the kernel should BUG when it encounters
1645	  data corruption in kernel memory structures when they get checked
1646	  for validity.
1647
1648	  If unsure, say N.
1649
1650config DEBUG_MAPLE_TREE
1651	bool "Debug maple trees"
1652	depends on DEBUG_KERNEL
1653	help
1654	  Enable maple tree debugging information and extra validations.
1655
1656	  If unsure, say N.
1657
1658endmenu
1659
1660config DEBUG_CREDENTIALS
1661	bool "Debug credential management"
1662	depends on DEBUG_KERNEL
1663	help
1664	  Enable this to turn on some debug checking for credential
1665	  management.  The additional code keeps track of the number of
1666	  pointers from task_structs to any given cred struct, and checks to
1667	  see that this number never exceeds the usage count of the cred
1668	  struct.
1669
1670	  Furthermore, if SELinux is enabled, this also checks that the
1671	  security pointer in the cred struct is never seen to be invalid.
1672
1673	  If unsure, say N.
1674
1675source "kernel/rcu/Kconfig.debug"
1676
1677config DEBUG_WQ_FORCE_RR_CPU
1678	bool "Force round-robin CPU selection for unbound work items"
1679	depends on DEBUG_KERNEL
1680	default n
1681	help
1682	  Workqueue used to implicitly guarantee that work items queued
1683	  without explicit CPU specified are put on the local CPU.  This
1684	  guarantee is no longer true and while local CPU is still
1685	  preferred work items may be put on foreign CPUs.  Kernel
1686	  parameter "workqueue.debug_force_rr_cpu" is added to force
1687	  round-robin CPU selection to flush out usages which depend on the
1688	  now broken guarantee.  This config option enables the debug
1689	  feature by default.  When enabled, memory and cache locality will
1690	  be impacted.
1691
1692config CPU_HOTPLUG_STATE_CONTROL
1693	bool "Enable CPU hotplug state control"
1694	depends on DEBUG_KERNEL
1695	depends on HOTPLUG_CPU
1696	default n
1697	help
1698	  Allows to write steps between "offline" and "online" to the CPUs
1699	  sysfs target file so states can be stepped granular. This is a debug
1700	  option for now as the hotplug machinery cannot be stopped and
1701	  restarted at arbitrary points yet.
1702
1703	  Say N if your are unsure.
1704
1705config LATENCYTOP
1706	bool "Latency measuring infrastructure"
1707	depends on DEBUG_KERNEL
1708	depends on STACKTRACE_SUPPORT
1709	depends on PROC_FS
1710	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1711	select KALLSYMS
1712	select KALLSYMS_ALL
1713	select STACKTRACE
1714	select SCHEDSTATS
1715	help
1716	  Enable this option if you want to use the LatencyTOP tool
1717	  to find out which userspace is blocking on what kernel operations.
1718
1719config DEBUG_CGROUP_REF
1720	bool "Disable inlining of cgroup css reference count functions"
1721	depends on DEBUG_KERNEL
1722	depends on CGROUPS
1723	depends on KPROBES
1724	default n
1725	help
1726	  Force cgroup css reference count functions to not be inlined so
1727	  that they can be kprobed for debugging.
1728
1729source "kernel/trace/Kconfig"
1730
1731config PROVIDE_OHCI1394_DMA_INIT
1732	bool "Remote debugging over FireWire early on boot"
1733	depends on PCI && X86
1734	help
1735	  If you want to debug problems which hang or crash the kernel early
1736	  on boot and the crashing machine has a FireWire port, you can use
1737	  this feature to remotely access the memory of the crashed machine
1738	  over FireWire. This employs remote DMA as part of the OHCI1394
1739	  specification which is now the standard for FireWire controllers.
1740
1741	  With remote DMA, you can monitor the printk buffer remotely using
1742	  firescope and access all memory below 4GB using fireproxy from gdb.
1743	  Even controlling a kernel debugger is possible using remote DMA.
1744
1745	  Usage:
1746
1747	  If ohci1394_dma=early is used as boot parameter, it will initialize
1748	  all OHCI1394 controllers which are found in the PCI config space.
1749
1750	  As all changes to the FireWire bus such as enabling and disabling
1751	  devices cause a bus reset and thereby disable remote DMA for all
1752	  devices, be sure to have the cable plugged and FireWire enabled on
1753	  the debugging host before booting the debug target for debugging.
1754
1755	  This code (~1k) is freed after boot. By then, the firewire stack
1756	  in charge of the OHCI-1394 controllers should be used instead.
1757
1758	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1759
1760source "samples/Kconfig"
1761
1762config ARCH_HAS_DEVMEM_IS_ALLOWED
1763	bool
1764
1765config STRICT_DEVMEM
1766	bool "Filter access to /dev/mem"
1767	depends on MMU && DEVMEM
1768	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1769	default y if PPC || X86 || ARM64
1770	help
1771	  If this option is disabled, you allow userspace (root) access to all
1772	  of memory, including kernel and userspace memory. Accidental
1773	  access to this is obviously disastrous, but specific access can
1774	  be used by people debugging the kernel. Note that with PAT support
1775	  enabled, even in this case there are restrictions on /dev/mem
1776	  use due to the cache aliasing requirements.
1777
1778	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1779	  file only allows userspace access to PCI space and the BIOS code and
1780	  data regions.  This is sufficient for dosemu and X and all common
1781	  users of /dev/mem.
1782
1783	  If in doubt, say Y.
1784
1785config IO_STRICT_DEVMEM
1786	bool "Filter I/O access to /dev/mem"
1787	depends on STRICT_DEVMEM
1788	help
1789	  If this option is disabled, you allow userspace (root) access to all
1790	  io-memory regardless of whether a driver is actively using that
1791	  range.  Accidental access to this is obviously disastrous, but
1792	  specific access can be used by people debugging kernel drivers.
1793
1794	  If this option is switched on, the /dev/mem file only allows
1795	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1796	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1797	  if the driver using a given range cannot be disabled.
1798
1799	  If in doubt, say Y.
1800
1801menu "$(SRCARCH) Debugging"
1802
1803source "arch/$(SRCARCH)/Kconfig.debug"
1804
1805endmenu
1806
1807menu "Kernel Testing and Coverage"
1808
1809source "lib/kunit/Kconfig"
1810
1811config NOTIFIER_ERROR_INJECTION
1812	tristate "Notifier error injection"
1813	depends on DEBUG_KERNEL
1814	select DEBUG_FS
1815	help
1816	  This option provides the ability to inject artificial errors to
1817	  specified notifier chain callbacks. It is useful to test the error
1818	  handling of notifier call chain failures.
1819
1820	  Say N if unsure.
1821
1822config PM_NOTIFIER_ERROR_INJECT
1823	tristate "PM notifier error injection module"
1824	depends on PM && NOTIFIER_ERROR_INJECTION
1825	default m if PM_DEBUG
1826	help
1827	  This option provides the ability to inject artificial errors to
1828	  PM notifier chain callbacks.  It is controlled through debugfs
1829	  interface /sys/kernel/debug/notifier-error-inject/pm
1830
1831	  If the notifier call chain should be failed with some events
1832	  notified, write the error code to "actions/<notifier event>/error".
1833
1834	  Example: Inject PM suspend error (-12 = -ENOMEM)
1835
1836	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1837	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1838	  # echo mem > /sys/power/state
1839	  bash: echo: write error: Cannot allocate memory
1840
1841	  To compile this code as a module, choose M here: the module will
1842	  be called pm-notifier-error-inject.
1843
1844	  If unsure, say N.
1845
1846config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1847	tristate "OF reconfig notifier error injection module"
1848	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1849	help
1850	  This option provides the ability to inject artificial errors to
1851	  OF reconfig notifier chain callbacks.  It is controlled
1852	  through debugfs interface under
1853	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1854
1855	  If the notifier call chain should be failed with some events
1856	  notified, write the error code to "actions/<notifier event>/error".
1857
1858	  To compile this code as a module, choose M here: the module will
1859	  be called of-reconfig-notifier-error-inject.
1860
1861	  If unsure, say N.
1862
1863config NETDEV_NOTIFIER_ERROR_INJECT
1864	tristate "Netdev notifier error injection module"
1865	depends on NET && NOTIFIER_ERROR_INJECTION
1866	help
1867	  This option provides the ability to inject artificial errors to
1868	  netdevice notifier chain callbacks.  It is controlled through debugfs
1869	  interface /sys/kernel/debug/notifier-error-inject/netdev
1870
1871	  If the notifier call chain should be failed with some events
1872	  notified, write the error code to "actions/<notifier event>/error".
1873
1874	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
1875
1876	  # cd /sys/kernel/debug/notifier-error-inject/netdev
1877	  # echo -22 > actions/NETDEV_CHANGEMTU/error
1878	  # ip link set eth0 mtu 1024
1879	  RTNETLINK answers: Invalid argument
1880
1881	  To compile this code as a module, choose M here: the module will
1882	  be called netdev-notifier-error-inject.
1883
1884	  If unsure, say N.
1885
1886config FUNCTION_ERROR_INJECTION
1887	bool "Fault-injections of functions"
1888	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1889	help
1890	  Add fault injections into various functions that are annotated with
1891	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1892	  value of these functions. This is useful to test error paths of code.
1893
1894	  If unsure, say N
1895
1896config FAULT_INJECTION
1897	bool "Fault-injection framework"
1898	depends on DEBUG_KERNEL
1899	help
1900	  Provide fault-injection framework.
1901	  For more details, see Documentation/fault-injection/.
1902
1903config FAILSLAB
1904	bool "Fault-injection capability for kmalloc"
1905	depends on FAULT_INJECTION
1906	depends on SLAB || SLUB
1907	help
1908	  Provide fault-injection capability for kmalloc.
1909
1910config FAIL_PAGE_ALLOC
1911	bool "Fault-injection capability for alloc_pages()"
1912	depends on FAULT_INJECTION
1913	help
1914	  Provide fault-injection capability for alloc_pages().
1915
1916config FAULT_INJECTION_USERCOPY
1917	bool "Fault injection capability for usercopy functions"
1918	depends on FAULT_INJECTION
1919	help
1920	  Provides fault-injection capability to inject failures
1921	  in usercopy functions (copy_from_user(), get_user(), ...).
1922
1923config FAIL_MAKE_REQUEST
1924	bool "Fault-injection capability for disk IO"
1925	depends on FAULT_INJECTION && BLOCK
1926	help
1927	  Provide fault-injection capability for disk IO.
1928
1929config FAIL_IO_TIMEOUT
1930	bool "Fault-injection capability for faking disk interrupts"
1931	depends on FAULT_INJECTION && BLOCK
1932	help
1933	  Provide fault-injection capability on end IO handling. This
1934	  will make the block layer "forget" an interrupt as configured,
1935	  thus exercising the error handling.
1936
1937	  Only works with drivers that use the generic timeout handling,
1938	  for others it won't do anything.
1939
1940config FAIL_FUTEX
1941	bool "Fault-injection capability for futexes"
1942	select DEBUG_FS
1943	depends on FAULT_INJECTION && FUTEX
1944	help
1945	  Provide fault-injection capability for futexes.
1946
1947config FAULT_INJECTION_DEBUG_FS
1948	bool "Debugfs entries for fault-injection capabilities"
1949	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1950	help
1951	  Enable configuration of fault-injection capabilities via debugfs.
1952
1953config FAIL_FUNCTION
1954	bool "Fault-injection capability for functions"
1955	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1956	help
1957	  Provide function-based fault-injection capability.
1958	  This will allow you to override a specific function with a return
1959	  with given return value. As a result, function caller will see
1960	  an error value and have to handle it. This is useful to test the
1961	  error handling in various subsystems.
1962
1963config FAIL_MMC_REQUEST
1964	bool "Fault-injection capability for MMC IO"
1965	depends on FAULT_INJECTION_DEBUG_FS && MMC
1966	help
1967	  Provide fault-injection capability for MMC IO.
1968	  This will make the mmc core return data errors. This is
1969	  useful to test the error handling in the mmc block device
1970	  and to test how the mmc host driver handles retries from
1971	  the block device.
1972
1973config FAIL_SUNRPC
1974	bool "Fault-injection capability for SunRPC"
1975	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1976	help
1977	  Provide fault-injection capability for SunRPC and
1978	  its consumers.
1979
1980config FAULT_INJECTION_CONFIGFS
1981	bool "Configfs interface for fault-injection capabilities"
1982	depends on FAULT_INJECTION
1983	select CONFIGFS_FS
1984	help
1985	  This option allows configfs-based drivers to dynamically configure
1986	  fault-injection via configfs.  Each parameter for driver-specific
1987	  fault-injection can be made visible as a configfs attribute in a
1988	  configfs group.
1989
1990
1991config FAULT_INJECTION_STACKTRACE_FILTER
1992	bool "stacktrace filter for fault-injection capabilities"
1993	depends on FAULT_INJECTION
1994	depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
1995	select STACKTRACE
1996	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1997	help
1998	  Provide stacktrace filter for fault-injection capabilities
1999
2000config ARCH_HAS_KCOV
2001	bool
2002	help
2003	  An architecture should select this when it can successfully
2004	  build and run with CONFIG_KCOV. This typically requires
2005	  disabling instrumentation for some early boot code.
2006
2007config CC_HAS_SANCOV_TRACE_PC
2008	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2009
2010
2011config KCOV
2012	bool "Code coverage for fuzzing"
2013	depends on ARCH_HAS_KCOV
2014	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2015	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2016		   GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2017	select DEBUG_FS
2018	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2019	select OBJTOOL if HAVE_NOINSTR_HACK
2020	help
2021	  KCOV exposes kernel code coverage information in a form suitable
2022	  for coverage-guided fuzzing (randomized testing).
2023
2024	  If RANDOMIZE_BASE is enabled, PC values will not be stable across
2025	  different machines and across reboots. If you need stable PC values,
2026	  disable RANDOMIZE_BASE.
2027
2028	  For more details, see Documentation/dev-tools/kcov.rst.
2029
2030config KCOV_ENABLE_COMPARISONS
2031	bool "Enable comparison operands collection by KCOV"
2032	depends on KCOV
2033	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2034	help
2035	  KCOV also exposes operands of every comparison in the instrumented
2036	  code along with operand sizes and PCs of the comparison instructions.
2037	  These operands can be used by fuzzing engines to improve the quality
2038	  of fuzzing coverage.
2039
2040config KCOV_INSTRUMENT_ALL
2041	bool "Instrument all code by default"
2042	depends on KCOV
2043	default y
2044	help
2045	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2046	  then you will want to instrument the whole kernel and you should
2047	  say y here. If you are doing more targeted fuzzing (like e.g.
2048	  filesystem fuzzing with AFL) then you will want to enable coverage
2049	  for more specific subsets of files, and should say n here.
2050
2051config KCOV_IRQ_AREA_SIZE
2052	hex "Size of interrupt coverage collection area in words"
2053	depends on KCOV
2054	default 0x40000
2055	help
2056	  KCOV uses preallocated per-cpu areas to collect coverage from
2057	  soft interrupts. This specifies the size of those areas in the
2058	  number of unsigned long words.
2059
2060menuconfig RUNTIME_TESTING_MENU
2061	bool "Runtime Testing"
2062	def_bool y
2063
2064if RUNTIME_TESTING_MENU
2065
2066config TEST_DHRY
2067	tristate "Dhrystone benchmark test"
2068	help
2069	  Enable this to include the Dhrystone 2.1 benchmark.  This test
2070	  calculates the number of Dhrystones per second, and the number of
2071	  DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2072	  by 1757 (the number of Dhrystones per second obtained on the VAX
2073	  11/780, nominally a 1 MIPS machine).
2074
2075	  To run the benchmark, it needs to be enabled explicitly, either from
2076	  the kernel command line (when built-in), or from userspace (when
2077	  built-in or modular.
2078
2079	  Run once during kernel boot:
2080
2081	      test_dhry.run
2082
2083	  Set number of iterations from kernel command line:
2084
2085	      test_dhry.iterations=<n>
2086
2087	  Set number of iterations from userspace:
2088
2089	      echo <n> > /sys/module/test_dhry/parameters/iterations
2090
2091	  Trigger manual run from userspace:
2092
2093	      echo y > /sys/module/test_dhry/parameters/run
2094
2095	  If the number of iterations is <= 0, the test will devise a suitable
2096	  number of iterations (test runs for at least 2s) automatically.
2097	  This process takes ca. 4s.
2098
2099	  If unsure, say N.
2100
2101config LKDTM
2102	tristate "Linux Kernel Dump Test Tool Module"
2103	depends on DEBUG_FS
2104	help
2105	This module enables testing of the different dumping mechanisms by
2106	inducing system failures at predefined crash points.
2107	If you don't need it: say N
2108	Choose M here to compile this code as a module. The module will be
2109	called lkdtm.
2110
2111	Documentation on how to use the module can be found in
2112	Documentation/fault-injection/provoke-crashes.rst
2113
2114config CPUMASK_KUNIT_TEST
2115	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2116	depends on KUNIT
2117	default KUNIT_ALL_TESTS
2118	help
2119	  Enable to turn on cpumask tests, running at boot or module load time.
2120
2121	  For more information on KUnit and unit tests in general, please refer
2122	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2123
2124	  If unsure, say N.
2125
2126config TEST_LIST_SORT
2127	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2128	depends on KUNIT
2129	default KUNIT_ALL_TESTS
2130	help
2131	  Enable this to turn on 'list_sort()' function test. This test is
2132	  executed only once during system boot (so affects only boot time),
2133	  or at module load time.
2134
2135	  If unsure, say N.
2136
2137config TEST_MIN_HEAP
2138	tristate "Min heap test"
2139	depends on DEBUG_KERNEL || m
2140	help
2141	  Enable this to turn on min heap function tests. This test is
2142	  executed only once during system boot (so affects only boot time),
2143	  or at module load time.
2144
2145	  If unsure, say N.
2146
2147config TEST_SORT
2148	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2149	depends on KUNIT
2150	default KUNIT_ALL_TESTS
2151	help
2152	  This option enables the self-test function of 'sort()' at boot,
2153	  or at module load time.
2154
2155	  If unsure, say N.
2156
2157config TEST_DIV64
2158	tristate "64bit/32bit division and modulo test"
2159	depends on DEBUG_KERNEL || m
2160	help
2161	  Enable this to turn on 'do_div()' function test. This test is
2162	  executed only once during system boot (so affects only boot time),
2163	  or at module load time.
2164
2165	  If unsure, say N.
2166
2167config KPROBES_SANITY_TEST
2168	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2169	depends on DEBUG_KERNEL
2170	depends on KPROBES
2171	depends on KUNIT
2172	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2173	default KUNIT_ALL_TESTS
2174	help
2175	  This option provides for testing basic kprobes functionality on
2176	  boot. Samples of kprobe and kretprobe are inserted and
2177	  verified for functionality.
2178
2179	  Say N if you are unsure.
2180
2181config FPROBE_SANITY_TEST
2182	bool "Self test for fprobe"
2183	depends on DEBUG_KERNEL
2184	depends on FPROBE
2185	depends on KUNIT=y
2186	help
2187	  This option will enable testing the fprobe when the system boot.
2188	  A series of tests are made to verify that the fprobe is functioning
2189	  properly.
2190
2191	  Say N if you are unsure.
2192
2193config BACKTRACE_SELF_TEST
2194	tristate "Self test for the backtrace code"
2195	depends on DEBUG_KERNEL
2196	help
2197	  This option provides a kernel module that can be used to test
2198	  the kernel stack backtrace code. This option is not useful
2199	  for distributions or general kernels, but only for kernel
2200	  developers working on architecture code.
2201
2202	  Note that if you want to also test saved backtraces, you will
2203	  have to enable STACKTRACE as well.
2204
2205	  Say N if you are unsure.
2206
2207config TEST_REF_TRACKER
2208	tristate "Self test for reference tracker"
2209	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2210	select REF_TRACKER
2211	help
2212	  This option provides a kernel module performing tests
2213	  using reference tracker infrastructure.
2214
2215	  Say N if you are unsure.
2216
2217config RBTREE_TEST
2218	tristate "Red-Black tree test"
2219	depends on DEBUG_KERNEL
2220	help
2221	  A benchmark measuring the performance of the rbtree library.
2222	  Also includes rbtree invariant checks.
2223
2224config REED_SOLOMON_TEST
2225	tristate "Reed-Solomon library test"
2226	depends on DEBUG_KERNEL || m
2227	select REED_SOLOMON
2228	select REED_SOLOMON_ENC16
2229	select REED_SOLOMON_DEC16
2230	help
2231	  This option enables the self-test function of rslib at boot,
2232	  or at module load time.
2233
2234	  If unsure, say N.
2235
2236config INTERVAL_TREE_TEST
2237	tristate "Interval tree test"
2238	depends on DEBUG_KERNEL
2239	select INTERVAL_TREE
2240	help
2241	  A benchmark measuring the performance of the interval tree library
2242
2243config PERCPU_TEST
2244	tristate "Per cpu operations test"
2245	depends on m && DEBUG_KERNEL
2246	help
2247	  Enable this option to build test module which validates per-cpu
2248	  operations.
2249
2250	  If unsure, say N.
2251
2252config ATOMIC64_SELFTEST
2253	tristate "Perform an atomic64_t self-test"
2254	help
2255	  Enable this option to test the atomic64_t functions at boot or
2256	  at module load time.
2257
2258	  If unsure, say N.
2259
2260config ASYNC_RAID6_TEST
2261	tristate "Self test for hardware accelerated raid6 recovery"
2262	depends on ASYNC_RAID6_RECOV
2263	select ASYNC_MEMCPY
2264	help
2265	  This is a one-shot self test that permutes through the
2266	  recovery of all the possible two disk failure scenarios for a
2267	  N-disk array.  Recovery is performed with the asynchronous
2268	  raid6 recovery routines, and will optionally use an offload
2269	  engine if one is available.
2270
2271	  If unsure, say N.
2272
2273config TEST_HEXDUMP
2274	tristate "Test functions located in the hexdump module at runtime"
2275
2276config STRING_SELFTEST
2277	tristate "Test string functions at runtime"
2278
2279config TEST_STRING_HELPERS
2280	tristate "Test functions located in the string_helpers module at runtime"
2281
2282config TEST_KSTRTOX
2283	tristate "Test kstrto*() family of functions at runtime"
2284
2285config TEST_PRINTF
2286	tristate "Test printf() family of functions at runtime"
2287
2288config TEST_SCANF
2289	tristate "Test scanf() family of functions at runtime"
2290
2291config TEST_BITMAP
2292	tristate "Test bitmap_*() family of functions at runtime"
2293	help
2294	  Enable this option to test the bitmap functions at boot.
2295
2296	  If unsure, say N.
2297
2298config TEST_UUID
2299	tristate "Test functions located in the uuid module at runtime"
2300
2301config TEST_XARRAY
2302	tristate "Test the XArray code at runtime"
2303
2304config TEST_MAPLE_TREE
2305	depends on DEBUG_KERNEL
2306	select DEBUG_MAPLE_TREE
2307	tristate "Test the Maple Tree code at runtime"
2308
2309config TEST_RHASHTABLE
2310	tristate "Perform selftest on resizable hash table"
2311	help
2312	  Enable this option to test the rhashtable functions at boot.
2313
2314	  If unsure, say N.
2315
2316config TEST_IDA
2317	tristate "Perform selftest on IDA functions"
2318
2319config TEST_PARMAN
2320	tristate "Perform selftest on priority array manager"
2321	depends on PARMAN
2322	help
2323	  Enable this option to test priority array manager on boot
2324	  (or module load).
2325
2326	  If unsure, say N.
2327
2328config TEST_IRQ_TIMINGS
2329	bool "IRQ timings selftest"
2330	depends on IRQ_TIMINGS
2331	help
2332	  Enable this option to test the irq timings code on boot.
2333
2334	  If unsure, say N.
2335
2336config TEST_LKM
2337	tristate "Test module loading with 'hello world' module"
2338	depends on m
2339	help
2340	  This builds the "test_module" module that emits "Hello, world"
2341	  on printk when loaded. It is designed to be used for basic
2342	  evaluation of the module loading subsystem (for example when
2343	  validating module verification). It lacks any extra dependencies,
2344	  and will not normally be loaded by the system unless explicitly
2345	  requested by name.
2346
2347	  If unsure, say N.
2348
2349config TEST_BITOPS
2350	tristate "Test module for compilation of bitops operations"
2351	depends on m
2352	help
2353	  This builds the "test_bitops" module that is much like the
2354	  TEST_LKM module except that it does a basic exercise of the
2355	  set/clear_bit macros and get_count_order/long to make sure there are
2356	  no compiler warnings from C=1 sparse checker or -Wextra
2357	  compilations. It has no dependencies and doesn't run or load unless
2358	  explicitly requested by name.  for example: modprobe test_bitops.
2359
2360	  If unsure, say N.
2361
2362config TEST_VMALLOC
2363	tristate "Test module for stress/performance analysis of vmalloc allocator"
2364	default n
2365       depends on MMU
2366	depends on m
2367	help
2368	  This builds the "test_vmalloc" module that should be used for
2369	  stress and performance analysis. So, any new change for vmalloc
2370	  subsystem can be evaluated from performance and stability point
2371	  of view.
2372
2373	  If unsure, say N.
2374
2375config TEST_USER_COPY
2376	tristate "Test user/kernel boundary protections"
2377	depends on m
2378	help
2379	  This builds the "test_user_copy" module that runs sanity checks
2380	  on the copy_to/from_user infrastructure, making sure basic
2381	  user/kernel boundary testing is working. If it fails to load,
2382	  a regression has been detected in the user/kernel memory boundary
2383	  protections.
2384
2385	  If unsure, say N.
2386
2387config TEST_BPF
2388	tristate "Test BPF filter functionality"
2389	depends on m && NET
2390	help
2391	  This builds the "test_bpf" module that runs various test vectors
2392	  against the BPF interpreter or BPF JIT compiler depending on the
2393	  current setting. This is in particular useful for BPF JIT compiler
2394	  development, but also to run regression tests against changes in
2395	  the interpreter code. It also enables test stubs for eBPF maps and
2396	  verifier used by user space verifier testsuite.
2397
2398	  If unsure, say N.
2399
2400config TEST_BLACKHOLE_DEV
2401	tristate "Test blackhole netdev functionality"
2402	depends on m && NET
2403	help
2404	  This builds the "test_blackhole_dev" module that validates the
2405	  data path through this blackhole netdev.
2406
2407	  If unsure, say N.
2408
2409config FIND_BIT_BENCHMARK
2410	tristate "Test find_bit functions"
2411	help
2412	  This builds the "test_find_bit" module that measure find_*_bit()
2413	  functions performance.
2414
2415	  If unsure, say N.
2416
2417config TEST_FIRMWARE
2418	tristate "Test firmware loading via userspace interface"
2419	depends on FW_LOADER
2420	help
2421	  This builds the "test_firmware" module that creates a userspace
2422	  interface for testing firmware loading. This can be used to
2423	  control the triggering of firmware loading without needing an
2424	  actual firmware-using device. The contents can be rechecked by
2425	  userspace.
2426
2427	  If unsure, say N.
2428
2429config TEST_SYSCTL
2430	tristate "sysctl test driver"
2431	depends on PROC_SYSCTL
2432	help
2433	  This builds the "test_sysctl" module. This driver enables to test the
2434	  proc sysctl interfaces available to drivers safely without affecting
2435	  production knobs which might alter system functionality.
2436
2437	  If unsure, say N.
2438
2439config BITFIELD_KUNIT
2440	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2441	depends on KUNIT
2442	default KUNIT_ALL_TESTS
2443	help
2444	  Enable this option to test the bitfield functions at boot.
2445
2446	  KUnit tests run during boot and output the results to the debug log
2447	  in TAP format (http://testanything.org/). Only useful for kernel devs
2448	  running the KUnit test harness, and not intended for inclusion into a
2449	  production build.
2450
2451	  For more information on KUnit and unit tests in general please refer
2452	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2453
2454	  If unsure, say N.
2455
2456config HASH_KUNIT_TEST
2457	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2458	depends on KUNIT
2459	default KUNIT_ALL_TESTS
2460	help
2461	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2462	  integer (<linux/hash.h>) hash functions on boot.
2463
2464	  KUnit tests run during boot and output the results to the debug log
2465	  in TAP format (https://testanything.org/). Only useful for kernel devs
2466	  running the KUnit test harness, and not intended for inclusion into a
2467	  production build.
2468
2469	  For more information on KUnit and unit tests in general please refer
2470	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2471
2472	  This is intended to help people writing architecture-specific
2473	  optimized versions. If unsure, say N.
2474
2475config RESOURCE_KUNIT_TEST
2476	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2477	depends on KUNIT
2478	default KUNIT_ALL_TESTS
2479	help
2480	  This builds the resource API unit test.
2481	  Tests the logic of API provided by resource.c and ioport.h.
2482	  For more information on KUnit and unit tests in general please refer
2483	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2484
2485	  If unsure, say N.
2486
2487config SYSCTL_KUNIT_TEST
2488	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2489	depends on KUNIT
2490	default KUNIT_ALL_TESTS
2491	help
2492	  This builds the proc sysctl unit test, which runs on boot.
2493	  Tests the API contract and implementation correctness of sysctl.
2494	  For more information on KUnit and unit tests in general please refer
2495	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2496
2497	  If unsure, say N.
2498
2499config LIST_KUNIT_TEST
2500	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2501	depends on KUNIT
2502	default KUNIT_ALL_TESTS
2503	help
2504	  This builds the linked list KUnit test suite.
2505	  It tests that the API and basic functionality of the list_head type
2506	  and associated macros.
2507
2508	  KUnit tests run during boot and output the results to the debug log
2509	  in TAP format (https://testanything.org/). Only useful for kernel devs
2510	  running the KUnit test harness, and not intended for inclusion into a
2511	  production build.
2512
2513	  For more information on KUnit and unit tests in general please refer
2514	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2515
2516	  If unsure, say N.
2517
2518config HASHTABLE_KUNIT_TEST
2519	tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2520	depends on KUNIT
2521	default KUNIT_ALL_TESTS
2522	help
2523	  This builds the hashtable KUnit test suite.
2524	  It tests the basic functionality of the API defined in
2525	  include/linux/hashtable.h. For more information on KUnit and
2526	  unit tests in general please refer to the KUnit documentation
2527	  in Documentation/dev-tools/kunit/.
2528
2529	  If unsure, say N.
2530
2531config LINEAR_RANGES_TEST
2532	tristate "KUnit test for linear_ranges"
2533	depends on KUNIT
2534	select LINEAR_RANGES
2535	help
2536	  This builds the linear_ranges unit test, which runs on boot.
2537	  Tests the linear_ranges logic correctness.
2538	  For more information on KUnit and unit tests in general please refer
2539	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2540
2541	  If unsure, say N.
2542
2543config CMDLINE_KUNIT_TEST
2544	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2545	depends on KUNIT
2546	default KUNIT_ALL_TESTS
2547	help
2548	  This builds the cmdline API unit test.
2549	  Tests the logic of API provided by cmdline.c.
2550	  For more information on KUnit and unit tests in general please refer
2551	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2552
2553	  If unsure, say N.
2554
2555config BITS_TEST
2556	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2557	depends on KUNIT
2558	default KUNIT_ALL_TESTS
2559	help
2560	  This builds the bits unit test.
2561	  Tests the logic of macros defined in bits.h.
2562	  For more information on KUnit and unit tests in general please refer
2563	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2564
2565	  If unsure, say N.
2566
2567config SLUB_KUNIT_TEST
2568	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2569	depends on SLUB_DEBUG && KUNIT
2570	default KUNIT_ALL_TESTS
2571	help
2572	  This builds SLUB allocator unit test.
2573	  Tests SLUB cache debugging functionality.
2574	  For more information on KUnit and unit tests in general please refer
2575	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2576
2577	  If unsure, say N.
2578
2579config RATIONAL_KUNIT_TEST
2580	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2581	depends on KUNIT && RATIONAL
2582	default KUNIT_ALL_TESTS
2583	help
2584	  This builds the rational math unit test.
2585	  For more information on KUnit and unit tests in general please refer
2586	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2587
2588	  If unsure, say N.
2589
2590config MEMCPY_KUNIT_TEST
2591	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2592	depends on KUNIT
2593	default KUNIT_ALL_TESTS
2594	help
2595	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2596	  For more information on KUnit and unit tests in general please refer
2597	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2598
2599	  If unsure, say N.
2600
2601config MEMCPY_SLOW_KUNIT_TEST
2602	bool "Include exhaustive memcpy tests"
2603	depends on MEMCPY_KUNIT_TEST
2604	default y
2605	help
2606	  Some memcpy tests are quite exhaustive in checking for overlaps
2607	  and bit ranges. These can be very slow, so they are split out
2608	  as a separate config, in case they need to be disabled.
2609
2610config IS_SIGNED_TYPE_KUNIT_TEST
2611	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2612	depends on KUNIT
2613	default KUNIT_ALL_TESTS
2614	help
2615	  Builds unit tests for the is_signed_type() macro.
2616
2617	  For more information on KUnit and unit tests in general please refer
2618	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2619
2620	  If unsure, say N.
2621
2622config OVERFLOW_KUNIT_TEST
2623	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2624	depends on KUNIT
2625	default KUNIT_ALL_TESTS
2626	help
2627	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2628	  related functions.
2629
2630	  For more information on KUnit and unit tests in general please refer
2631	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2632
2633	  If unsure, say N.
2634
2635config STACKINIT_KUNIT_TEST
2636	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2637	depends on KUNIT
2638	default KUNIT_ALL_TESTS
2639	help
2640	  Test if the kernel is zero-initializing stack variables and
2641	  padding. Coverage is controlled by compiler flags,
2642	  CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2643	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2644	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2645
2646config FORTIFY_KUNIT_TEST
2647	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2648	depends on KUNIT && FORTIFY_SOURCE
2649	default KUNIT_ALL_TESTS
2650	help
2651	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2652	  by the str*() and mem*() family of functions. For testing runtime
2653	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2654
2655config HW_BREAKPOINT_KUNIT_TEST
2656	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2657	depends on HAVE_HW_BREAKPOINT
2658	depends on KUNIT=y
2659	default KUNIT_ALL_TESTS
2660	help
2661	  Tests for hw_breakpoint constraints accounting.
2662
2663	  If unsure, say N.
2664
2665config STRSCPY_KUNIT_TEST
2666	tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2667	depends on KUNIT
2668	default KUNIT_ALL_TESTS
2669
2670config SIPHASH_KUNIT_TEST
2671	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2672	depends on KUNIT
2673	default KUNIT_ALL_TESTS
2674	help
2675	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2676	  functions on boot (or module load).
2677
2678	  This is intended to help people writing architecture-specific
2679	  optimized versions.  If unsure, say N.
2680
2681config TEST_UDELAY
2682	tristate "udelay test driver"
2683	help
2684	  This builds the "udelay_test" module that helps to make sure
2685	  that udelay() is working properly.
2686
2687	  If unsure, say N.
2688
2689config TEST_STATIC_KEYS
2690	tristate "Test static keys"
2691	depends on m
2692	help
2693	  Test the static key interfaces.
2694
2695	  If unsure, say N.
2696
2697config TEST_DYNAMIC_DEBUG
2698	tristate "Test DYNAMIC_DEBUG"
2699	depends on DYNAMIC_DEBUG
2700	help
2701	  This module registers a tracer callback to count enabled
2702	  pr_debugs in a 'do_debugging' function, then alters their
2703	  enablements, calls the function, and compares counts.
2704
2705	  If unsure, say N.
2706
2707config TEST_KMOD
2708	tristate "kmod stress tester"
2709	depends on m
2710	depends on NETDEVICES && NET_CORE && INET # for TUN
2711	depends on BLOCK
2712	depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2713	select TEST_LKM
2714	select XFS_FS
2715	select TUN
2716	select BTRFS_FS
2717	help
2718	  Test the kernel's module loading mechanism: kmod. kmod implements
2719	  support to load modules using the Linux kernel's usermode helper.
2720	  This test provides a series of tests against kmod.
2721
2722	  Although technically you can either build test_kmod as a module or
2723	  into the kernel we disallow building it into the kernel since
2724	  it stress tests request_module() and this will very likely cause
2725	  some issues by taking over precious threads available from other
2726	  module load requests, ultimately this could be fatal.
2727
2728	  To run tests run:
2729
2730	  tools/testing/selftests/kmod/kmod.sh --help
2731
2732	  If unsure, say N.
2733
2734config TEST_DEBUG_VIRTUAL
2735	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2736	depends on DEBUG_VIRTUAL
2737	help
2738	  Test the kernel's ability to detect incorrect calls to
2739	  virt_to_phys() done against the non-linear part of the
2740	  kernel's virtual address map.
2741
2742	  If unsure, say N.
2743
2744config TEST_MEMCAT_P
2745	tristate "Test memcat_p() helper function"
2746	help
2747	  Test the memcat_p() helper for correctly merging two
2748	  pointer arrays together.
2749
2750	  If unsure, say N.
2751
2752config TEST_LIVEPATCH
2753	tristate "Test livepatching"
2754	default n
2755	depends on DYNAMIC_DEBUG
2756	depends on LIVEPATCH
2757	depends on m
2758	help
2759	  Test kernel livepatching features for correctness.  The tests will
2760	  load test modules that will be livepatched in various scenarios.
2761
2762	  To run all the livepatching tests:
2763
2764	  make -C tools/testing/selftests TARGETS=livepatch run_tests
2765
2766	  Alternatively, individual tests may be invoked:
2767
2768	  tools/testing/selftests/livepatch/test-callbacks.sh
2769	  tools/testing/selftests/livepatch/test-livepatch.sh
2770	  tools/testing/selftests/livepatch/test-shadow-vars.sh
2771
2772	  If unsure, say N.
2773
2774config TEST_OBJAGG
2775	tristate "Perform selftest on object aggreration manager"
2776	default n
2777	depends on OBJAGG
2778	help
2779	  Enable this option to test object aggregation manager on boot
2780	  (or module load).
2781
2782config TEST_MEMINIT
2783	tristate "Test heap/page initialization"
2784	help
2785	  Test if the kernel is zero-initializing heap and page allocations.
2786	  This can be useful to test init_on_alloc and init_on_free features.
2787
2788	  If unsure, say N.
2789
2790config TEST_HMM
2791	tristate "Test HMM (Heterogeneous Memory Management)"
2792	depends on TRANSPARENT_HUGEPAGE
2793	depends on DEVICE_PRIVATE
2794	select HMM_MIRROR
2795	select MMU_NOTIFIER
2796	help
2797	  This is a pseudo device driver solely for testing HMM.
2798	  Say M here if you want to build the HMM test module.
2799	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2800
2801	  If unsure, say N.
2802
2803config TEST_FREE_PAGES
2804	tristate "Test freeing pages"
2805	help
2806	  Test that a memory leak does not occur due to a race between
2807	  freeing a block of pages and a speculative page reference.
2808	  Loading this module is safe if your kernel has the bug fixed.
2809	  If the bug is not fixed, it will leak gigabytes of memory and
2810	  probably OOM your system.
2811
2812config TEST_FPU
2813	tristate "Test floating point operations in kernel space"
2814	depends on X86 && !KCOV_INSTRUMENT_ALL
2815	help
2816	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2817	  which will trigger a sequence of floating point operations. This is used
2818	  for self-testing floating point control register setting in
2819	  kernel_fpu_begin().
2820
2821	  If unsure, say N.
2822
2823config TEST_CLOCKSOURCE_WATCHDOG
2824	tristate "Test clocksource watchdog in kernel space"
2825	depends on CLOCKSOURCE_WATCHDOG
2826	help
2827	  Enable this option to create a kernel module that will trigger
2828	  a test of the clocksource watchdog.  This module may be loaded
2829	  via modprobe or insmod in which case it will run upon being
2830	  loaded, or it may be built in, in which case it will run
2831	  shortly after boot.
2832
2833	  If unsure, say N.
2834
2835endif # RUNTIME_TESTING_MENU
2836
2837config ARCH_USE_MEMTEST
2838	bool
2839	help
2840	  An architecture should select this when it uses early_memtest()
2841	  during boot process.
2842
2843config MEMTEST
2844	bool "Memtest"
2845	depends on ARCH_USE_MEMTEST
2846	help
2847	  This option adds a kernel parameter 'memtest', which allows memtest
2848	  to be set and executed.
2849	        memtest=0, mean disabled; -- default
2850	        memtest=1, mean do 1 test pattern;
2851	        ...
2852	        memtest=17, mean do 17 test patterns.
2853	  If you are unsure how to answer this question, answer N.
2854
2855
2856
2857config HYPERV_TESTING
2858	bool "Microsoft Hyper-V driver testing"
2859	default n
2860	depends on HYPERV && DEBUG_FS
2861	help
2862	  Select this option to enable Hyper-V vmbus testing.
2863
2864endmenu # "Kernel Testing and Coverage"
2865
2866menu "Rust hacking"
2867
2868config RUST_DEBUG_ASSERTIONS
2869	bool "Debug assertions"
2870	depends on RUST
2871	help
2872	  Enables rustc's `-Cdebug-assertions` codegen option.
2873
2874	  This flag lets you turn `cfg(debug_assertions)` conditional
2875	  compilation on or off. This can be used to enable extra debugging
2876	  code in development but not in production. For example, it controls
2877	  the behavior of the standard library's `debug_assert!` macro.
2878
2879	  Note that this will apply to all Rust code, including `core`.
2880
2881	  If unsure, say N.
2882
2883config RUST_OVERFLOW_CHECKS
2884	bool "Overflow checks"
2885	default y
2886	depends on RUST
2887	help
2888	  Enables rustc's `-Coverflow-checks` codegen option.
2889
2890	  This flag allows you to control the behavior of runtime integer
2891	  overflow. When overflow-checks are enabled, a Rust panic will occur
2892	  on overflow.
2893
2894	  Note that this will apply to all Rust code, including `core`.
2895
2896	  If unsure, say Y.
2897
2898config RUST_BUILD_ASSERT_ALLOW
2899	bool "Allow unoptimized build-time assertions"
2900	depends on RUST
2901	help
2902	  Controls how are `build_error!` and `build_assert!` handled during build.
2903
2904	  If calls to them exist in the binary, it may indicate a violated invariant
2905	  or that the optimizer failed to verify the invariant during compilation.
2906
2907	  This should not happen, thus by default the build is aborted. However,
2908	  as an escape hatch, you can choose Y here to ignore them during build
2909	  and let the check be carried at runtime (with `panic!` being called if
2910	  the check fails).
2911
2912	  If unsure, say N.
2913
2914endmenu # "Rust"
2915
2916endmenu # Kernel hacking
2917