xref: /openbmc/linux/lib/Kconfig.debug (revision 436396f2)
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)
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 HAVE_DEBUG_KMEMLEAK
756	bool
757
758config DEBUG_KMEMLEAK
759	bool "Kernel memory leak detector"
760	depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
761	select DEBUG_FS
762	select STACKTRACE if STACKTRACE_SUPPORT
763	select KALLSYMS
764	select CRC32
765	select STACKDEPOT
766	select STACKDEPOT_ALWAYS_INIT if !DEBUG_KMEMLEAK_DEFAULT_OFF
767	help
768	  Say Y here if you want to enable the memory leak
769	  detector. The memory allocation/freeing is traced in a way
770	  similar to the Boehm's conservative garbage collector, the
771	  difference being that the orphan objects are not freed but
772	  only shown in /sys/kernel/debug/kmemleak. Enabling this
773	  feature will introduce an overhead to memory
774	  allocations. See Documentation/dev-tools/kmemleak.rst for more
775	  details.
776
777	  Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
778	  of finding leaks due to the slab objects poisoning.
779
780	  In order to access the kmemleak file, debugfs needs to be
781	  mounted (usually at /sys/kernel/debug).
782
783config DEBUG_KMEMLEAK_MEM_POOL_SIZE
784	int "Kmemleak memory pool size"
785	depends on DEBUG_KMEMLEAK
786	range 200 1000000
787	default 16000
788	help
789	  Kmemleak must track all the memory allocations to avoid
790	  reporting false positives. Since memory may be allocated or
791	  freed before kmemleak is fully initialised, use a static pool
792	  of metadata objects to track such callbacks. After kmemleak is
793	  fully initialised, this memory pool acts as an emergency one
794	  if slab allocations fail.
795
796config DEBUG_KMEMLEAK_TEST
797	tristate "Simple test for the kernel memory leak detector"
798	depends on DEBUG_KMEMLEAK && m
799	help
800	  This option enables a module that explicitly leaks memory.
801
802	  If unsure, say N.
803
804config DEBUG_KMEMLEAK_DEFAULT_OFF
805	bool "Default kmemleak to off"
806	depends on DEBUG_KMEMLEAK
807	help
808	  Say Y here to disable kmemleak by default. It can then be enabled
809	  on the command line via kmemleak=on.
810
811config DEBUG_KMEMLEAK_AUTO_SCAN
812	bool "Enable kmemleak auto scan thread on boot up"
813	default y
814	depends on DEBUG_KMEMLEAK
815	help
816	  Depending on the cpu, kmemleak scan may be cpu intensive and can
817	  stall user tasks at times. This option enables/disables automatic
818	  kmemleak scan at boot up.
819
820	  Say N here to disable kmemleak auto scan thread to stop automatic
821	  scanning. Disabling this option disables automatic reporting of
822	  memory leaks.
823
824	  If unsure, say Y.
825
826config DEBUG_STACK_USAGE
827	bool "Stack utilization instrumentation"
828	depends on DEBUG_KERNEL && !IA64
829	help
830	  Enables the display of the minimum amount of free stack which each
831	  task has ever had available in the sysrq-T and sysrq-P debug output.
832
833	  This option will slow down process creation somewhat.
834
835config SCHED_STACK_END_CHECK
836	bool "Detect stack corruption on calls to schedule()"
837	depends on DEBUG_KERNEL
838	default n
839	help
840	  This option checks for a stack overrun on calls to schedule().
841	  If the stack end location is found to be over written always panic as
842	  the content of the corrupted region can no longer be trusted.
843	  This is to ensure no erroneous behaviour occurs which could result in
844	  data corruption or a sporadic crash at a later stage once the region
845	  is examined. The runtime overhead introduced is minimal.
846
847config ARCH_HAS_DEBUG_VM_PGTABLE
848	bool
849	help
850	  An architecture should select this when it can successfully
851	  build and run DEBUG_VM_PGTABLE.
852
853config DEBUG_VM_IRQSOFF
854	def_bool DEBUG_VM && !PREEMPT_RT
855
856config DEBUG_VM
857	bool "Debug VM"
858	depends on DEBUG_KERNEL
859	help
860	  Enable this to turn on extended checks in the virtual-memory system
861	  that may impact performance.
862
863	  If unsure, say N.
864
865config DEBUG_VM_MAPLE_TREE
866	bool "Debug VM maple trees"
867	depends on DEBUG_VM
868	select DEBUG_MAPLE_TREE
869	help
870	  Enable VM maple tree debugging information and extra validations.
871
872	  If unsure, say N.
873
874config DEBUG_VM_RB
875	bool "Debug VM red-black trees"
876	depends on DEBUG_VM
877	help
878	  Enable VM red-black tree debugging information and extra validations.
879
880	  If unsure, say N.
881
882config DEBUG_VM_PGFLAGS
883	bool "Debug page-flags operations"
884	depends on DEBUG_VM
885	help
886	  Enables extra validation on page flags operations.
887
888	  If unsure, say N.
889
890config DEBUG_VM_PGTABLE
891	bool "Debug arch page table for semantics compliance"
892	depends on MMU
893	depends on ARCH_HAS_DEBUG_VM_PGTABLE
894	default y if DEBUG_VM
895	help
896	  This option provides a debug method which can be used to test
897	  architecture page table helper functions on various platforms in
898	  verifying if they comply with expected generic MM semantics. This
899	  will help architecture code in making sure that any changes or
900	  new additions of these helpers still conform to expected
901	  semantics of the generic MM. Platforms will have to opt in for
902	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
903
904	  If unsure, say N.
905
906config ARCH_HAS_DEBUG_VIRTUAL
907	bool
908
909config DEBUG_VIRTUAL
910	bool "Debug VM translations"
911	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
912	help
913	  Enable some costly sanity checks in virtual to page code. This can
914	  catch mistakes with virt_to_page() and friends.
915
916	  If unsure, say N.
917
918config DEBUG_NOMMU_REGIONS
919	bool "Debug the global anon/private NOMMU mapping region tree"
920	depends on DEBUG_KERNEL && !MMU
921	help
922	  This option causes the global tree of anonymous and private mapping
923	  regions to be regularly checked for invalid topology.
924
925config DEBUG_MEMORY_INIT
926	bool "Debug memory initialisation" if EXPERT
927	default !EXPERT
928	help
929	  Enable this for additional checks during memory initialisation.
930	  The sanity checks verify aspects of the VM such as the memory model
931	  and other information provided by the architecture. Verbose
932	  information will be printed at KERN_DEBUG loglevel depending
933	  on the mminit_loglevel= command-line option.
934
935	  If unsure, say Y
936
937config MEMORY_NOTIFIER_ERROR_INJECT
938	tristate "Memory hotplug notifier error injection module"
939	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
940	help
941	  This option provides the ability to inject artificial errors to
942	  memory hotplug notifier chain callbacks.  It is controlled through
943	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
944
945	  If the notifier call chain should be failed with some events
946	  notified, write the error code to "actions/<notifier event>/error".
947
948	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
949
950	  # cd /sys/kernel/debug/notifier-error-inject/memory
951	  # echo -12 > actions/MEM_GOING_OFFLINE/error
952	  # echo offline > /sys/devices/system/memory/memoryXXX/state
953	  bash: echo: write error: Cannot allocate memory
954
955	  To compile this code as a module, choose M here: the module will
956	  be called memory-notifier-error-inject.
957
958	  If unsure, say N.
959
960config DEBUG_PER_CPU_MAPS
961	bool "Debug access to per_cpu maps"
962	depends on DEBUG_KERNEL
963	depends on SMP
964	help
965	  Say Y to verify that the per_cpu map being accessed has
966	  been set up. This adds a fair amount of code to kernel memory
967	  and decreases performance.
968
969	  Say N if unsure.
970
971config DEBUG_KMAP_LOCAL
972	bool "Debug kmap_local temporary mappings"
973	depends on DEBUG_KERNEL && KMAP_LOCAL
974	help
975	  This option enables additional error checking for the kmap_local
976	  infrastructure.  Disable for production use.
977
978config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
979	bool
980
981config DEBUG_KMAP_LOCAL_FORCE_MAP
982	bool "Enforce kmap_local temporary mappings"
983	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
984	select KMAP_LOCAL
985	select DEBUG_KMAP_LOCAL
986	help
987	  This option enforces temporary mappings through the kmap_local
988	  mechanism for non-highmem pages and on non-highmem systems.
989	  Disable this for production systems!
990
991config DEBUG_HIGHMEM
992	bool "Highmem debugging"
993	depends on DEBUG_KERNEL && HIGHMEM
994	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
995	select DEBUG_KMAP_LOCAL
996	help
997	  This option enables additional error checking for high memory
998	  systems.  Disable for production systems.
999
1000config HAVE_DEBUG_STACKOVERFLOW
1001	bool
1002
1003config DEBUG_STACKOVERFLOW
1004	bool "Check for stack overflows"
1005	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
1006	help
1007	  Say Y here if you want to check for overflows of kernel, IRQ
1008	  and exception stacks (if your architecture uses them). This
1009	  option will show detailed messages if free stack space drops
1010	  below a certain limit.
1011
1012	  These kinds of bugs usually occur when call-chains in the
1013	  kernel get too deep, especially when interrupts are
1014	  involved.
1015
1016	  Use this in cases where you see apparently random memory
1017	  corruption, especially if it appears in 'struct thread_info'
1018
1019	  If in doubt, say "N".
1020
1021source "lib/Kconfig.kasan"
1022source "lib/Kconfig.kfence"
1023source "lib/Kconfig.kmsan"
1024
1025endmenu # "Memory Debugging"
1026
1027config DEBUG_SHIRQ
1028	bool "Debug shared IRQ handlers"
1029	depends on DEBUG_KERNEL
1030	help
1031	  Enable this to generate a spurious interrupt just before a shared
1032	  interrupt handler is deregistered (generating one when registering
1033	  is currently disabled). Drivers need to handle this correctly. Some
1034	  don't and need to be caught.
1035
1036menu "Debug Oops, Lockups and Hangs"
1037
1038config PANIC_ON_OOPS
1039	bool "Panic on Oops"
1040	help
1041	  Say Y here to enable the kernel to panic when it oopses. This
1042	  has the same effect as setting oops=panic on the kernel command
1043	  line.
1044
1045	  This feature is useful to ensure that the kernel does not do
1046	  anything erroneous after an oops which could result in data
1047	  corruption or other issues.
1048
1049	  Say N if unsure.
1050
1051config PANIC_ON_OOPS_VALUE
1052	int
1053	range 0 1
1054	default 0 if !PANIC_ON_OOPS
1055	default 1 if PANIC_ON_OOPS
1056
1057config PANIC_TIMEOUT
1058	int "panic timeout"
1059	default 0
1060	help
1061	  Set the timeout value (in seconds) until a reboot occurs when
1062	  the kernel panics. If n = 0, then we wait forever. A timeout
1063	  value n > 0 will wait n seconds before rebooting, while a timeout
1064	  value n < 0 will reboot immediately.
1065
1066config LOCKUP_DETECTOR
1067	bool
1068
1069config SOFTLOCKUP_DETECTOR
1070	bool "Detect Soft Lockups"
1071	depends on DEBUG_KERNEL && !S390
1072	select LOCKUP_DETECTOR
1073	help
1074	  Say Y here to enable the kernel to act as a watchdog to detect
1075	  soft lockups.
1076
1077	  Softlockups are bugs that cause the kernel to loop in kernel
1078	  mode for more than 20 seconds, without giving other tasks a
1079	  chance to run.  The current stack trace is displayed upon
1080	  detection and the system will stay locked up.
1081
1082config BOOTPARAM_SOFTLOCKUP_PANIC
1083	bool "Panic (Reboot) On Soft Lockups"
1084	depends on SOFTLOCKUP_DETECTOR
1085	help
1086	  Say Y here to enable the kernel to panic on "soft lockups",
1087	  which are bugs that cause the kernel to loop in kernel
1088	  mode for more than 20 seconds (configurable using the watchdog_thresh
1089	  sysctl), without giving other tasks a chance to run.
1090
1091	  The panic can be used in combination with panic_timeout,
1092	  to cause the system to reboot automatically after a
1093	  lockup has been detected. This feature is useful for
1094	  high-availability systems that have uptime guarantees and
1095	  where a lockup must be resolved ASAP.
1096
1097	  Say N if unsure.
1098
1099config HARDLOCKUP_DETECTOR_PERF
1100	bool
1101	select SOFTLOCKUP_DETECTOR
1102
1103#
1104# Enables a timestamp based low pass filter to compensate for perf based
1105# hard lockup detection which runs too fast due to turbo modes.
1106#
1107config HARDLOCKUP_CHECK_TIMESTAMP
1108	bool
1109
1110#
1111# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1112# lockup detector rather than the perf based detector.
1113#
1114config HARDLOCKUP_DETECTOR
1115	bool "Detect Hard Lockups"
1116	depends on DEBUG_KERNEL && !S390
1117	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1118	select LOCKUP_DETECTOR
1119	select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1120	help
1121	  Say Y here to enable the kernel to act as a watchdog to detect
1122	  hard lockups.
1123
1124	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1125	  for more than 10 seconds, without letting other interrupts have a
1126	  chance to run.  The current stack trace is displayed upon detection
1127	  and the system will stay locked up.
1128
1129config BOOTPARAM_HARDLOCKUP_PANIC
1130	bool "Panic (Reboot) On Hard Lockups"
1131	depends on HARDLOCKUP_DETECTOR
1132	help
1133	  Say Y here to enable the kernel to panic on "hard lockups",
1134	  which are bugs that cause the kernel to loop in kernel
1135	  mode with interrupts disabled for more than 10 seconds (configurable
1136	  using the watchdog_thresh sysctl).
1137
1138	  Say N if unsure.
1139
1140config DETECT_HUNG_TASK
1141	bool "Detect Hung Tasks"
1142	depends on DEBUG_KERNEL
1143	default SOFTLOCKUP_DETECTOR
1144	help
1145	  Say Y here to enable the kernel to detect "hung tasks",
1146	  which are bugs that cause the task to be stuck in
1147	  uninterruptible "D" state indefinitely.
1148
1149	  When a hung task is detected, the kernel will print the
1150	  current stack trace (which you should report), but the
1151	  task will stay in uninterruptible state. If lockdep is
1152	  enabled then all held locks will also be reported. This
1153	  feature has negligible overhead.
1154
1155config DEFAULT_HUNG_TASK_TIMEOUT
1156	int "Default timeout for hung task detection (in seconds)"
1157	depends on DETECT_HUNG_TASK
1158	default 120
1159	help
1160	  This option controls the default timeout (in seconds) used
1161	  to determine when a task has become non-responsive and should
1162	  be considered hung.
1163
1164	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1165	  sysctl or by writing a value to
1166	  /proc/sys/kernel/hung_task_timeout_secs.
1167
1168	  A timeout of 0 disables the check.  The default is two minutes.
1169	  Keeping the default should be fine in most cases.
1170
1171config BOOTPARAM_HUNG_TASK_PANIC
1172	bool "Panic (Reboot) On Hung Tasks"
1173	depends on DETECT_HUNG_TASK
1174	help
1175	  Say Y here to enable the kernel to panic on "hung tasks",
1176	  which are bugs that cause the kernel to leave a task stuck
1177	  in uninterruptible "D" state.
1178
1179	  The panic can be used in combination with panic_timeout,
1180	  to cause the system to reboot automatically after a
1181	  hung task has been detected. This feature is useful for
1182	  high-availability systems that have uptime guarantees and
1183	  where a hung tasks must be resolved ASAP.
1184
1185	  Say N if unsure.
1186
1187config WQ_WATCHDOG
1188	bool "Detect Workqueue Stalls"
1189	depends on DEBUG_KERNEL
1190	help
1191	  Say Y here to enable stall detection on workqueues.  If a
1192	  worker pool doesn't make forward progress on a pending work
1193	  item for over a given amount of time, 30s by default, a
1194	  warning message is printed along with dump of workqueue
1195	  state.  This can be configured through kernel parameter
1196	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1197
1198config TEST_LOCKUP
1199	tristate "Test module to generate lockups"
1200	depends on m
1201	help
1202	  This builds the "test_lockup" module that helps to make sure
1203	  that watchdogs and lockup detectors are working properly.
1204
1205	  Depending on module parameters it could emulate soft or hard
1206	  lockup, "hung task", or locking arbitrary lock for a long time.
1207	  Also it could generate series of lockups with cooling-down periods.
1208
1209	  If unsure, say N.
1210
1211endmenu # "Debug lockups and hangs"
1212
1213menu "Scheduler Debugging"
1214
1215config SCHED_DEBUG
1216	bool "Collect scheduler debugging info"
1217	depends on DEBUG_KERNEL && PROC_FS
1218	default y
1219	help
1220	  If you say Y here, the /sys/kernel/debug/sched file will be provided
1221	  that can help debug the scheduler. The runtime overhead of this
1222	  option is minimal.
1223
1224config SCHED_INFO
1225	bool
1226	default n
1227
1228config SCHEDSTATS
1229	bool "Collect scheduler statistics"
1230	depends on DEBUG_KERNEL && PROC_FS
1231	select SCHED_INFO
1232	help
1233	  If you say Y here, additional code will be inserted into the
1234	  scheduler and related routines to collect statistics about
1235	  scheduler behavior and provide them in /proc/schedstat.  These
1236	  stats may be useful for both tuning and debugging the scheduler
1237	  If you aren't debugging the scheduler or trying to tune a specific
1238	  application, you can say N to avoid the very slight overhead
1239	  this adds.
1240
1241endmenu
1242
1243config DEBUG_TIMEKEEPING
1244	bool "Enable extra timekeeping sanity checking"
1245	help
1246	  This option will enable additional timekeeping sanity checks
1247	  which may be helpful when diagnosing issues where timekeeping
1248	  problems are suspected.
1249
1250	  This may include checks in the timekeeping hotpaths, so this
1251	  option may have a (very small) performance impact to some
1252	  workloads.
1253
1254	  If unsure, say N.
1255
1256config DEBUG_PREEMPT
1257	bool "Debug preemptible kernel"
1258	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1259	default y
1260	help
1261	  If you say Y here then the kernel will use a debug variant of the
1262	  commonly used smp_processor_id() function and will print warnings
1263	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1264	  will detect preemption count underflows.
1265
1266menu "Lock Debugging (spinlocks, mutexes, etc...)"
1267
1268config LOCK_DEBUGGING_SUPPORT
1269	bool
1270	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1271	default y
1272
1273config PROVE_LOCKING
1274	bool "Lock debugging: prove locking correctness"
1275	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1276	select LOCKDEP
1277	select DEBUG_SPINLOCK
1278	select DEBUG_MUTEXES if !PREEMPT_RT
1279	select DEBUG_RT_MUTEXES if RT_MUTEXES
1280	select DEBUG_RWSEMS
1281	select DEBUG_WW_MUTEX_SLOWPATH
1282	select DEBUG_LOCK_ALLOC
1283	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1284	select TRACE_IRQFLAGS
1285	default n
1286	help
1287	 This feature enables the kernel to prove that all locking
1288	 that occurs in the kernel runtime is mathematically
1289	 correct: that under no circumstance could an arbitrary (and
1290	 not yet triggered) combination of observed locking
1291	 sequences (on an arbitrary number of CPUs, running an
1292	 arbitrary number of tasks and interrupt contexts) cause a
1293	 deadlock.
1294
1295	 In short, this feature enables the kernel to report locking
1296	 related deadlocks before they actually occur.
1297
1298	 The proof does not depend on how hard and complex a
1299	 deadlock scenario would be to trigger: how many
1300	 participant CPUs, tasks and irq-contexts would be needed
1301	 for it to trigger. The proof also does not depend on
1302	 timing: if a race and a resulting deadlock is possible
1303	 theoretically (no matter how unlikely the race scenario
1304	 is), it will be proven so and will immediately be
1305	 reported by the kernel (once the event is observed that
1306	 makes the deadlock theoretically possible).
1307
1308	 If a deadlock is impossible (i.e. the locking rules, as
1309	 observed by the kernel, are mathematically correct), the
1310	 kernel reports nothing.
1311
1312	 NOTE: this feature can also be enabled for rwlocks, mutexes
1313	 and rwsems - in which case all dependencies between these
1314	 different locking variants are observed and mapped too, and
1315	 the proof of observed correctness is also maintained for an
1316	 arbitrary combination of these separate locking variants.
1317
1318	 For more details, see Documentation/locking/lockdep-design.rst.
1319
1320config PROVE_RAW_LOCK_NESTING
1321	bool "Enable raw_spinlock - spinlock nesting checks"
1322	depends on PROVE_LOCKING
1323	default n
1324	help
1325	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1326	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1327	 not violated.
1328
1329	 NOTE: There are known nesting problems. So if you enable this
1330	 option expect lockdep splats until these problems have been fully
1331	 addressed which is work in progress. This config switch allows to
1332	 identify and analyze these problems. It will be removed and the
1333	 check permanently enabled once the main issues have been fixed.
1334
1335	 If unsure, select N.
1336
1337config LOCK_STAT
1338	bool "Lock usage statistics"
1339	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1340	select LOCKDEP
1341	select DEBUG_SPINLOCK
1342	select DEBUG_MUTEXES if !PREEMPT_RT
1343	select DEBUG_RT_MUTEXES if RT_MUTEXES
1344	select DEBUG_LOCK_ALLOC
1345	default n
1346	help
1347	 This feature enables tracking lock contention points
1348
1349	 For more details, see Documentation/locking/lockstat.rst
1350
1351	 This also enables lock events required by "perf lock",
1352	 subcommand of perf.
1353	 If you want to use "perf lock", you also need to turn on
1354	 CONFIG_EVENT_TRACING.
1355
1356	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1357	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1358
1359config DEBUG_RT_MUTEXES
1360	bool "RT Mutex debugging, deadlock detection"
1361	depends on DEBUG_KERNEL && RT_MUTEXES
1362	help
1363	 This allows rt mutex semantics violations and rt mutex related
1364	 deadlocks (lockups) to be detected and reported automatically.
1365
1366config DEBUG_SPINLOCK
1367	bool "Spinlock and rw-lock debugging: basic checks"
1368	depends on DEBUG_KERNEL
1369	select UNINLINE_SPIN_UNLOCK
1370	help
1371	  Say Y here and build SMP to catch missing spinlock initialization
1372	  and certain other kinds of spinlock errors commonly made.  This is
1373	  best used in conjunction with the NMI watchdog so that spinlock
1374	  deadlocks are also debuggable.
1375
1376config DEBUG_MUTEXES
1377	bool "Mutex debugging: basic checks"
1378	depends on DEBUG_KERNEL && !PREEMPT_RT
1379	help
1380	 This feature allows mutex semantics violations to be detected and
1381	 reported.
1382
1383config DEBUG_WW_MUTEX_SLOWPATH
1384	bool "Wait/wound mutex debugging: Slowpath testing"
1385	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1386	select DEBUG_LOCK_ALLOC
1387	select DEBUG_SPINLOCK
1388	select DEBUG_MUTEXES if !PREEMPT_RT
1389	select DEBUG_RT_MUTEXES if PREEMPT_RT
1390	help
1391	 This feature enables slowpath testing for w/w mutex users by
1392	 injecting additional -EDEADLK wound/backoff cases. Together with
1393	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1394	 will test all possible w/w mutex interface abuse with the
1395	 exception of simply not acquiring all the required locks.
1396	 Note that this feature can introduce significant overhead, so
1397	 it really should not be enabled in a production or distro kernel,
1398	 even a debug kernel.  If you are a driver writer, enable it.  If
1399	 you are a distro, do not.
1400
1401config DEBUG_RWSEMS
1402	bool "RW Semaphore debugging: basic checks"
1403	depends on DEBUG_KERNEL
1404	help
1405	  This debugging feature allows mismatched rw semaphore locks
1406	  and unlocks to be detected and reported.
1407
1408config DEBUG_LOCK_ALLOC
1409	bool "Lock debugging: detect incorrect freeing of live locks"
1410	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1411	select DEBUG_SPINLOCK
1412	select DEBUG_MUTEXES if !PREEMPT_RT
1413	select DEBUG_RT_MUTEXES if RT_MUTEXES
1414	select LOCKDEP
1415	help
1416	 This feature will check whether any held lock (spinlock, rwlock,
1417	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1418	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1419	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1420	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1421	 held during task exit.
1422
1423config LOCKDEP
1424	bool
1425	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1426	select STACKTRACE
1427	select KALLSYMS
1428	select KALLSYMS_ALL
1429
1430config LOCKDEP_SMALL
1431	bool
1432
1433config LOCKDEP_BITS
1434	int "Bitsize for MAX_LOCKDEP_ENTRIES"
1435	depends on LOCKDEP && !LOCKDEP_SMALL
1436	range 10 30
1437	default 15
1438	help
1439	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1440
1441config LOCKDEP_CHAINS_BITS
1442	int "Bitsize for MAX_LOCKDEP_CHAINS"
1443	depends on LOCKDEP && !LOCKDEP_SMALL
1444	range 10 30
1445	default 16
1446	help
1447	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1448
1449config LOCKDEP_STACK_TRACE_BITS
1450	int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1451	depends on LOCKDEP && !LOCKDEP_SMALL
1452	range 10 30
1453	default 19
1454	help
1455	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1456
1457config LOCKDEP_STACK_TRACE_HASH_BITS
1458	int "Bitsize for STACK_TRACE_HASH_SIZE"
1459	depends on LOCKDEP && !LOCKDEP_SMALL
1460	range 10 30
1461	default 14
1462	help
1463	  Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1464
1465config LOCKDEP_CIRCULAR_QUEUE_BITS
1466	int "Bitsize for elements in circular_queue struct"
1467	depends on LOCKDEP
1468	range 10 30
1469	default 12
1470	help
1471	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1472
1473config DEBUG_LOCKDEP
1474	bool "Lock dependency engine debugging"
1475	depends on DEBUG_KERNEL && LOCKDEP
1476	select DEBUG_IRQFLAGS
1477	help
1478	  If you say Y here, the lock dependency engine will do
1479	  additional runtime checks to debug itself, at the price
1480	  of more runtime overhead.
1481
1482config DEBUG_ATOMIC_SLEEP
1483	bool "Sleep inside atomic section checking"
1484	select PREEMPT_COUNT
1485	depends on DEBUG_KERNEL
1486	depends on !ARCH_NO_PREEMPT
1487	help
1488	  If you say Y here, various routines which may sleep will become very
1489	  noisy if they are called inside atomic sections: when a spinlock is
1490	  held, inside an rcu read side critical section, inside preempt disabled
1491	  sections, inside an interrupt, etc...
1492
1493config DEBUG_LOCKING_API_SELFTESTS
1494	bool "Locking API boot-time self-tests"
1495	depends on DEBUG_KERNEL
1496	help
1497	  Say Y here if you want the kernel to run a short self-test during
1498	  bootup. The self-test checks whether common types of locking bugs
1499	  are detected by debugging mechanisms or not. (if you disable
1500	  lock debugging then those bugs won't be detected of course.)
1501	  The following locking APIs are covered: spinlocks, rwlocks,
1502	  mutexes and rwsems.
1503
1504config LOCK_TORTURE_TEST
1505	tristate "torture tests for locking"
1506	depends on DEBUG_KERNEL
1507	select TORTURE_TEST
1508	help
1509	  This option provides a kernel module that runs torture tests
1510	  on kernel locking primitives.  The kernel module may be built
1511	  after the fact on the running kernel to be tested, if desired.
1512
1513	  Say Y here if you want kernel locking-primitive torture tests
1514	  to be built into the kernel.
1515	  Say M if you want these torture tests to build as a module.
1516	  Say N if you are unsure.
1517
1518config WW_MUTEX_SELFTEST
1519	tristate "Wait/wound mutex selftests"
1520	help
1521	  This option provides a kernel module that runs tests on the
1522	  on the struct ww_mutex locking API.
1523
1524	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1525	  with this test harness.
1526
1527	  Say M if you want these self tests to build as a module.
1528	  Say N if you are unsure.
1529
1530config SCF_TORTURE_TEST
1531	tristate "torture tests for smp_call_function*()"
1532	depends on DEBUG_KERNEL
1533	select TORTURE_TEST
1534	help
1535	  This option provides a kernel module that runs torture tests
1536	  on the smp_call_function() family of primitives.  The kernel
1537	  module may be built after the fact on the running kernel to
1538	  be tested, if desired.
1539
1540config CSD_LOCK_WAIT_DEBUG
1541	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1542	depends on DEBUG_KERNEL
1543	depends on 64BIT
1544	default n
1545	help
1546	  This option enables debug prints when CPUs are slow to respond
1547	  to the smp_call_function*() IPI wrappers.  These debug prints
1548	  include the IPI handler function currently executing (if any)
1549	  and relevant stack traces.
1550
1551endmenu # lock debugging
1552
1553config TRACE_IRQFLAGS
1554	depends on TRACE_IRQFLAGS_SUPPORT
1555	bool
1556	help
1557	  Enables hooks to interrupt enabling and disabling for
1558	  either tracing or lock debugging.
1559
1560config TRACE_IRQFLAGS_NMI
1561	def_bool y
1562	depends on TRACE_IRQFLAGS
1563	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1564
1565config DEBUG_IRQFLAGS
1566	bool "Debug IRQ flag manipulation"
1567	help
1568	  Enables checks for potentially unsafe enabling or disabling of
1569	  interrupts, such as calling raw_local_irq_restore() when interrupts
1570	  are enabled.
1571
1572config STACKTRACE
1573	bool "Stack backtrace support"
1574	depends on STACKTRACE_SUPPORT
1575	help
1576	  This option causes the kernel to create a /proc/pid/stack for
1577	  every process, showing its current stack trace.
1578	  It is also used by various kernel debugging features that require
1579	  stack trace generation.
1580
1581config WARN_ALL_UNSEEDED_RANDOM
1582	bool "Warn for all uses of unseeded randomness"
1583	default n
1584	help
1585	  Some parts of the kernel contain bugs relating to their use of
1586	  cryptographically secure random numbers before it's actually possible
1587	  to generate those numbers securely. This setting ensures that these
1588	  flaws don't go unnoticed, by enabling a message, should this ever
1589	  occur. This will allow people with obscure setups to know when things
1590	  are going wrong, so that they might contact developers about fixing
1591	  it.
1592
1593	  Unfortunately, on some models of some architectures getting
1594	  a fully seeded CRNG is extremely difficult, and so this can
1595	  result in dmesg getting spammed for a surprisingly long
1596	  time.  This is really bad from a security perspective, and
1597	  so architecture maintainers really need to do what they can
1598	  to get the CRNG seeded sooner after the system is booted.
1599	  However, since users cannot do anything actionable to
1600	  address this, by default this option is disabled.
1601
1602	  Say Y here if you want to receive warnings for all uses of
1603	  unseeded randomness.  This will be of use primarily for
1604	  those developers interested in improving the security of
1605	  Linux kernels running on their architecture (or
1606	  subarchitecture).
1607
1608config DEBUG_KOBJECT
1609	bool "kobject debugging"
1610	depends on DEBUG_KERNEL
1611	help
1612	  If you say Y here, some extra kobject debugging messages will be sent
1613	  to the syslog.
1614
1615config DEBUG_KOBJECT_RELEASE
1616	bool "kobject release debugging"
1617	depends on DEBUG_OBJECTS_TIMERS
1618	help
1619	  kobjects are reference counted objects.  This means that their
1620	  last reference count put is not predictable, and the kobject can
1621	  live on past the point at which a driver decides to drop its
1622	  initial reference to the kobject gained on allocation.  An
1623	  example of this would be a struct device which has just been
1624	  unregistered.
1625
1626	  However, some buggy drivers assume that after such an operation,
1627	  the memory backing the kobject can be immediately freed.  This
1628	  goes completely against the principles of a refcounted object.
1629
1630	  If you say Y here, the kernel will delay the release of kobjects
1631	  on the last reference count to improve the visibility of this
1632	  kind of kobject release bug.
1633
1634config HAVE_DEBUG_BUGVERBOSE
1635	bool
1636
1637menu "Debug kernel data structures"
1638
1639config DEBUG_LIST
1640	bool "Debug linked list manipulation"
1641	depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1642	help
1643	  Enable this to turn on extended checks in the linked-list
1644	  walking routines.
1645
1646	  If unsure, say N.
1647
1648config DEBUG_PLIST
1649	bool "Debug priority linked list manipulation"
1650	depends on DEBUG_KERNEL
1651	help
1652	  Enable this to turn on extended checks in the priority-ordered
1653	  linked-list (plist) walking routines.  This checks the entire
1654	  list multiple times during each manipulation.
1655
1656	  If unsure, say N.
1657
1658config DEBUG_SG
1659	bool "Debug SG table operations"
1660	depends on DEBUG_KERNEL
1661	help
1662	  Enable this to turn on checks on scatter-gather tables. This can
1663	  help find problems with drivers that do not properly initialize
1664	  their sg tables.
1665
1666	  If unsure, say N.
1667
1668config DEBUG_NOTIFIERS
1669	bool "Debug notifier call chains"
1670	depends on DEBUG_KERNEL
1671	help
1672	  Enable this to turn on sanity checking for notifier call chains.
1673	  This is most useful for kernel developers to make sure that
1674	  modules properly unregister themselves from notifier chains.
1675	  This is a relatively cheap check but if you care about maximum
1676	  performance, say N.
1677
1678config BUG_ON_DATA_CORRUPTION
1679	bool "Trigger a BUG when data corruption is detected"
1680	select DEBUG_LIST
1681	help
1682	  Select this option if the kernel should BUG when it encounters
1683	  data corruption in kernel memory structures when they get checked
1684	  for validity.
1685
1686	  If unsure, say N.
1687
1688config DEBUG_MAPLE_TREE
1689	bool "Debug maple trees"
1690	depends on DEBUG_KERNEL
1691	help
1692	  Enable maple tree debugging information and extra validations.
1693
1694	  If unsure, say N.
1695
1696endmenu
1697
1698config DEBUG_CREDENTIALS
1699	bool "Debug credential management"
1700	depends on DEBUG_KERNEL
1701	help
1702	  Enable this to turn on some debug checking for credential
1703	  management.  The additional code keeps track of the number of
1704	  pointers from task_structs to any given cred struct, and checks to
1705	  see that this number never exceeds the usage count of the cred
1706	  struct.
1707
1708	  Furthermore, if SELinux is enabled, this also checks that the
1709	  security pointer in the cred struct is never seen to be invalid.
1710
1711	  If unsure, say N.
1712
1713source "kernel/rcu/Kconfig.debug"
1714
1715config DEBUG_WQ_FORCE_RR_CPU
1716	bool "Force round-robin CPU selection for unbound work items"
1717	depends on DEBUG_KERNEL
1718	default n
1719	help
1720	  Workqueue used to implicitly guarantee that work items queued
1721	  without explicit CPU specified are put on the local CPU.  This
1722	  guarantee is no longer true and while local CPU is still
1723	  preferred work items may be put on foreign CPUs.  Kernel
1724	  parameter "workqueue.debug_force_rr_cpu" is added to force
1725	  round-robin CPU selection to flush out usages which depend on the
1726	  now broken guarantee.  This config option enables the debug
1727	  feature by default.  When enabled, memory and cache locality will
1728	  be impacted.
1729
1730config CPU_HOTPLUG_STATE_CONTROL
1731	bool "Enable CPU hotplug state control"
1732	depends on DEBUG_KERNEL
1733	depends on HOTPLUG_CPU
1734	default n
1735	help
1736	  Allows to write steps between "offline" and "online" to the CPUs
1737	  sysfs target file so states can be stepped granular. This is a debug
1738	  option for now as the hotplug machinery cannot be stopped and
1739	  restarted at arbitrary points yet.
1740
1741	  Say N if your are unsure.
1742
1743config LATENCYTOP
1744	bool "Latency measuring infrastructure"
1745	depends on DEBUG_KERNEL
1746	depends on STACKTRACE_SUPPORT
1747	depends on PROC_FS
1748	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1749	select KALLSYMS
1750	select KALLSYMS_ALL
1751	select STACKTRACE
1752	select SCHEDSTATS
1753	help
1754	  Enable this option if you want to use the LatencyTOP tool
1755	  to find out which userspace is blocking on what kernel operations.
1756
1757config DEBUG_CGROUP_REF
1758	bool "Disable inlining of cgroup css reference count functions"
1759	depends on DEBUG_KERNEL
1760	depends on CGROUPS
1761	depends on KPROBES
1762	default n
1763	help
1764	  Force cgroup css reference count functions to not be inlined so
1765	  that they can be kprobed for debugging.
1766
1767source "kernel/trace/Kconfig"
1768
1769config PROVIDE_OHCI1394_DMA_INIT
1770	bool "Remote debugging over FireWire early on boot"
1771	depends on PCI && X86
1772	help
1773	  If you want to debug problems which hang or crash the kernel early
1774	  on boot and the crashing machine has a FireWire port, you can use
1775	  this feature to remotely access the memory of the crashed machine
1776	  over FireWire. This employs remote DMA as part of the OHCI1394
1777	  specification which is now the standard for FireWire controllers.
1778
1779	  With remote DMA, you can monitor the printk buffer remotely using
1780	  firescope and access all memory below 4GB using fireproxy from gdb.
1781	  Even controlling a kernel debugger is possible using remote DMA.
1782
1783	  Usage:
1784
1785	  If ohci1394_dma=early is used as boot parameter, it will initialize
1786	  all OHCI1394 controllers which are found in the PCI config space.
1787
1788	  As all changes to the FireWire bus such as enabling and disabling
1789	  devices cause a bus reset and thereby disable remote DMA for all
1790	  devices, be sure to have the cable plugged and FireWire enabled on
1791	  the debugging host before booting the debug target for debugging.
1792
1793	  This code (~1k) is freed after boot. By then, the firewire stack
1794	  in charge of the OHCI-1394 controllers should be used instead.
1795
1796	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1797
1798source "samples/Kconfig"
1799
1800config ARCH_HAS_DEVMEM_IS_ALLOWED
1801	bool
1802
1803config STRICT_DEVMEM
1804	bool "Filter access to /dev/mem"
1805	depends on MMU && DEVMEM
1806	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1807	default y if PPC || X86 || ARM64
1808	help
1809	  If this option is disabled, you allow userspace (root) access to all
1810	  of memory, including kernel and userspace memory. Accidental
1811	  access to this is obviously disastrous, but specific access can
1812	  be used by people debugging the kernel. Note that with PAT support
1813	  enabled, even in this case there are restrictions on /dev/mem
1814	  use due to the cache aliasing requirements.
1815
1816	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1817	  file only allows userspace access to PCI space and the BIOS code and
1818	  data regions.  This is sufficient for dosemu and X and all common
1819	  users of /dev/mem.
1820
1821	  If in doubt, say Y.
1822
1823config IO_STRICT_DEVMEM
1824	bool "Filter I/O access to /dev/mem"
1825	depends on STRICT_DEVMEM
1826	help
1827	  If this option is disabled, you allow userspace (root) access to all
1828	  io-memory regardless of whether a driver is actively using that
1829	  range.  Accidental access to this is obviously disastrous, but
1830	  specific access can be used by people debugging kernel drivers.
1831
1832	  If this option is switched on, the /dev/mem file only allows
1833	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1834	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1835	  if the driver using a given range cannot be disabled.
1836
1837	  If in doubt, say Y.
1838
1839menu "$(SRCARCH) Debugging"
1840
1841source "arch/$(SRCARCH)/Kconfig.debug"
1842
1843endmenu
1844
1845menu "Kernel Testing and Coverage"
1846
1847source "lib/kunit/Kconfig"
1848
1849config NOTIFIER_ERROR_INJECTION
1850	tristate "Notifier error injection"
1851	depends on DEBUG_KERNEL
1852	select DEBUG_FS
1853	help
1854	  This option provides the ability to inject artificial errors to
1855	  specified notifier chain callbacks. It is useful to test the error
1856	  handling of notifier call chain failures.
1857
1858	  Say N if unsure.
1859
1860config PM_NOTIFIER_ERROR_INJECT
1861	tristate "PM notifier error injection module"
1862	depends on PM && NOTIFIER_ERROR_INJECTION
1863	default m if PM_DEBUG
1864	help
1865	  This option provides the ability to inject artificial errors to
1866	  PM notifier chain callbacks.  It is controlled through debugfs
1867	  interface /sys/kernel/debug/notifier-error-inject/pm
1868
1869	  If the notifier call chain should be failed with some events
1870	  notified, write the error code to "actions/<notifier event>/error".
1871
1872	  Example: Inject PM suspend error (-12 = -ENOMEM)
1873
1874	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1875	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1876	  # echo mem > /sys/power/state
1877	  bash: echo: write error: Cannot allocate memory
1878
1879	  To compile this code as a module, choose M here: the module will
1880	  be called pm-notifier-error-inject.
1881
1882	  If unsure, say N.
1883
1884config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1885	tristate "OF reconfig notifier error injection module"
1886	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1887	help
1888	  This option provides the ability to inject artificial errors to
1889	  OF reconfig notifier chain callbacks.  It is controlled
1890	  through debugfs interface under
1891	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1892
1893	  If the notifier call chain should be failed with some events
1894	  notified, write the error code to "actions/<notifier event>/error".
1895
1896	  To compile this code as a module, choose M here: the module will
1897	  be called of-reconfig-notifier-error-inject.
1898
1899	  If unsure, say N.
1900
1901config NETDEV_NOTIFIER_ERROR_INJECT
1902	tristate "Netdev notifier error injection module"
1903	depends on NET && NOTIFIER_ERROR_INJECTION
1904	help
1905	  This option provides the ability to inject artificial errors to
1906	  netdevice notifier chain callbacks.  It is controlled through debugfs
1907	  interface /sys/kernel/debug/notifier-error-inject/netdev
1908
1909	  If the notifier call chain should be failed with some events
1910	  notified, write the error code to "actions/<notifier event>/error".
1911
1912	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
1913
1914	  # cd /sys/kernel/debug/notifier-error-inject/netdev
1915	  # echo -22 > actions/NETDEV_CHANGEMTU/error
1916	  # ip link set eth0 mtu 1024
1917	  RTNETLINK answers: Invalid argument
1918
1919	  To compile this code as a module, choose M here: the module will
1920	  be called netdev-notifier-error-inject.
1921
1922	  If unsure, say N.
1923
1924config FUNCTION_ERROR_INJECTION
1925	bool "Fault-injections of functions"
1926	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1927	help
1928	  Add fault injections into various functions that are annotated with
1929	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1930	  value of these functions. This is useful to test error paths of code.
1931
1932	  If unsure, say N
1933
1934config FAULT_INJECTION
1935	bool "Fault-injection framework"
1936	depends on DEBUG_KERNEL
1937	help
1938	  Provide fault-injection framework.
1939	  For more details, see Documentation/fault-injection/.
1940
1941config FAILSLAB
1942	bool "Fault-injection capability for kmalloc"
1943	depends on FAULT_INJECTION
1944	depends on SLAB || SLUB
1945	help
1946	  Provide fault-injection capability for kmalloc.
1947
1948config FAIL_PAGE_ALLOC
1949	bool "Fault-injection capability for alloc_pages()"
1950	depends on FAULT_INJECTION
1951	help
1952	  Provide fault-injection capability for alloc_pages().
1953
1954config FAULT_INJECTION_USERCOPY
1955	bool "Fault injection capability for usercopy functions"
1956	depends on FAULT_INJECTION
1957	help
1958	  Provides fault-injection capability to inject failures
1959	  in usercopy functions (copy_from_user(), get_user(), ...).
1960
1961config FAIL_MAKE_REQUEST
1962	bool "Fault-injection capability for disk IO"
1963	depends on FAULT_INJECTION && BLOCK
1964	help
1965	  Provide fault-injection capability for disk IO.
1966
1967config FAIL_IO_TIMEOUT
1968	bool "Fault-injection capability for faking disk interrupts"
1969	depends on FAULT_INJECTION && BLOCK
1970	help
1971	  Provide fault-injection capability on end IO handling. This
1972	  will make the block layer "forget" an interrupt as configured,
1973	  thus exercising the error handling.
1974
1975	  Only works with drivers that use the generic timeout handling,
1976	  for others it won't do anything.
1977
1978config FAIL_FUTEX
1979	bool "Fault-injection capability for futexes"
1980	select DEBUG_FS
1981	depends on FAULT_INJECTION && FUTEX
1982	help
1983	  Provide fault-injection capability for futexes.
1984
1985config FAULT_INJECTION_DEBUG_FS
1986	bool "Debugfs entries for fault-injection capabilities"
1987	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1988	help
1989	  Enable configuration of fault-injection capabilities via debugfs.
1990
1991config FAIL_FUNCTION
1992	bool "Fault-injection capability for functions"
1993	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1994	help
1995	  Provide function-based fault-injection capability.
1996	  This will allow you to override a specific function with a return
1997	  with given return value. As a result, function caller will see
1998	  an error value and have to handle it. This is useful to test the
1999	  error handling in various subsystems.
2000
2001config FAIL_MMC_REQUEST
2002	bool "Fault-injection capability for MMC IO"
2003	depends on FAULT_INJECTION_DEBUG_FS && MMC
2004	help
2005	  Provide fault-injection capability for MMC IO.
2006	  This will make the mmc core return data errors. This is
2007	  useful to test the error handling in the mmc block device
2008	  and to test how the mmc host driver handles retries from
2009	  the block device.
2010
2011config FAIL_SUNRPC
2012	bool "Fault-injection capability for SunRPC"
2013	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2014	help
2015	  Provide fault-injection capability for SunRPC and
2016	  its consumers.
2017
2018config FAULT_INJECTION_STACKTRACE_FILTER
2019	bool "stacktrace filter for fault-injection capabilities"
2020	depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2021	select STACKTRACE
2022	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2023	help
2024	  Provide stacktrace filter for fault-injection capabilities
2025
2026config ARCH_HAS_KCOV
2027	bool
2028	help
2029	  An architecture should select this when it can successfully
2030	  build and run with CONFIG_KCOV. This typically requires
2031	  disabling instrumentation for some early boot code.
2032
2033config CC_HAS_SANCOV_TRACE_PC
2034	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2035
2036
2037config KCOV
2038	bool "Code coverage for fuzzing"
2039	depends on ARCH_HAS_KCOV
2040	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2041	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2042		   GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2043	select DEBUG_FS
2044	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2045	select OBJTOOL if HAVE_NOINSTR_HACK
2046	help
2047	  KCOV exposes kernel code coverage information in a form suitable
2048	  for coverage-guided fuzzing (randomized testing).
2049
2050	  If RANDOMIZE_BASE is enabled, PC values will not be stable across
2051	  different machines and across reboots. If you need stable PC values,
2052	  disable RANDOMIZE_BASE.
2053
2054	  For more details, see Documentation/dev-tools/kcov.rst.
2055
2056config KCOV_ENABLE_COMPARISONS
2057	bool "Enable comparison operands collection by KCOV"
2058	depends on KCOV
2059	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2060	help
2061	  KCOV also exposes operands of every comparison in the instrumented
2062	  code along with operand sizes and PCs of the comparison instructions.
2063	  These operands can be used by fuzzing engines to improve the quality
2064	  of fuzzing coverage.
2065
2066config KCOV_INSTRUMENT_ALL
2067	bool "Instrument all code by default"
2068	depends on KCOV
2069	default y
2070	help
2071	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2072	  then you will want to instrument the whole kernel and you should
2073	  say y here. If you are doing more targeted fuzzing (like e.g.
2074	  filesystem fuzzing with AFL) then you will want to enable coverage
2075	  for more specific subsets of files, and should say n here.
2076
2077config KCOV_IRQ_AREA_SIZE
2078	hex "Size of interrupt coverage collection area in words"
2079	depends on KCOV
2080	default 0x40000
2081	help
2082	  KCOV uses preallocated per-cpu areas to collect coverage from
2083	  soft interrupts. This specifies the size of those areas in the
2084	  number of unsigned long words.
2085
2086menuconfig RUNTIME_TESTING_MENU
2087	bool "Runtime Testing"
2088	def_bool y
2089
2090if RUNTIME_TESTING_MENU
2091
2092config LKDTM
2093	tristate "Linux Kernel Dump Test Tool Module"
2094	depends on DEBUG_FS
2095	help
2096	This module enables testing of the different dumping mechanisms by
2097	inducing system failures at predefined crash points.
2098	If you don't need it: say N
2099	Choose M here to compile this code as a module. The module will be
2100	called lkdtm.
2101
2102	Documentation on how to use the module can be found in
2103	Documentation/fault-injection/provoke-crashes.rst
2104
2105config CPUMASK_KUNIT_TEST
2106	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2107	depends on KUNIT
2108	default KUNIT_ALL_TESTS
2109	help
2110	  Enable to turn on cpumask tests, running at boot or module load time.
2111
2112	  For more information on KUnit and unit tests in general, please refer
2113	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2114
2115	  If unsure, say N.
2116
2117config TEST_LIST_SORT
2118	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2119	depends on KUNIT
2120	default KUNIT_ALL_TESTS
2121	help
2122	  Enable this to turn on 'list_sort()' function test. This test is
2123	  executed only once during system boot (so affects only boot time),
2124	  or at module load time.
2125
2126	  If unsure, say N.
2127
2128config TEST_MIN_HEAP
2129	tristate "Min heap test"
2130	depends on DEBUG_KERNEL || m
2131	help
2132	  Enable this to turn on min heap function tests. This test is
2133	  executed only once during system boot (so affects only boot time),
2134	  or at module load time.
2135
2136	  If unsure, say N.
2137
2138config TEST_SORT
2139	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2140	depends on KUNIT
2141	default KUNIT_ALL_TESTS
2142	help
2143	  This option enables the self-test function of 'sort()' at boot,
2144	  or at module load time.
2145
2146	  If unsure, say N.
2147
2148config TEST_DIV64
2149	tristate "64bit/32bit division and modulo test"
2150	depends on DEBUG_KERNEL || m
2151	help
2152	  Enable this to turn on 'do_div()' function test. This test is
2153	  executed only once during system boot (so affects only boot time),
2154	  or at module load time.
2155
2156	  If unsure, say N.
2157
2158config KPROBES_SANITY_TEST
2159	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2160	depends on DEBUG_KERNEL
2161	depends on KPROBES
2162	depends on KUNIT
2163	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2164	default KUNIT_ALL_TESTS
2165	help
2166	  This option provides for testing basic kprobes functionality on
2167	  boot. Samples of kprobe and kretprobe are inserted and
2168	  verified for functionality.
2169
2170	  Say N if you are unsure.
2171
2172config FPROBE_SANITY_TEST
2173	bool "Self test for fprobe"
2174	depends on DEBUG_KERNEL
2175	depends on FPROBE
2176	depends on KUNIT=y
2177	help
2178	  This option will enable testing the fprobe when the system boot.
2179	  A series of tests are made to verify that the fprobe is functioning
2180	  properly.
2181
2182	  Say N if you are unsure.
2183
2184config BACKTRACE_SELF_TEST
2185	tristate "Self test for the backtrace code"
2186	depends on DEBUG_KERNEL
2187	help
2188	  This option provides a kernel module that can be used to test
2189	  the kernel stack backtrace code. This option is not useful
2190	  for distributions or general kernels, but only for kernel
2191	  developers working on architecture code.
2192
2193	  Note that if you want to also test saved backtraces, you will
2194	  have to enable STACKTRACE as well.
2195
2196	  Say N if you are unsure.
2197
2198config TEST_REF_TRACKER
2199	tristate "Self test for reference tracker"
2200	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2201	select REF_TRACKER
2202	help
2203	  This option provides a kernel module performing tests
2204	  using reference tracker infrastructure.
2205
2206	  Say N if you are unsure.
2207
2208config RBTREE_TEST
2209	tristate "Red-Black tree test"
2210	depends on DEBUG_KERNEL
2211	help
2212	  A benchmark measuring the performance of the rbtree library.
2213	  Also includes rbtree invariant checks.
2214
2215config REED_SOLOMON_TEST
2216	tristate "Reed-Solomon library test"
2217	depends on DEBUG_KERNEL || m
2218	select REED_SOLOMON
2219	select REED_SOLOMON_ENC16
2220	select REED_SOLOMON_DEC16
2221	help
2222	  This option enables the self-test function of rslib at boot,
2223	  or at module load time.
2224
2225	  If unsure, say N.
2226
2227config INTERVAL_TREE_TEST
2228	tristate "Interval tree test"
2229	depends on DEBUG_KERNEL
2230	select INTERVAL_TREE
2231	help
2232	  A benchmark measuring the performance of the interval tree library
2233
2234config PERCPU_TEST
2235	tristate "Per cpu operations test"
2236	depends on m && DEBUG_KERNEL
2237	help
2238	  Enable this option to build test module which validates per-cpu
2239	  operations.
2240
2241	  If unsure, say N.
2242
2243config ATOMIC64_SELFTEST
2244	tristate "Perform an atomic64_t self-test"
2245	help
2246	  Enable this option to test the atomic64_t functions at boot or
2247	  at module load time.
2248
2249	  If unsure, say N.
2250
2251config ASYNC_RAID6_TEST
2252	tristate "Self test for hardware accelerated raid6 recovery"
2253	depends on ASYNC_RAID6_RECOV
2254	select ASYNC_MEMCPY
2255	help
2256	  This is a one-shot self test that permutes through the
2257	  recovery of all the possible two disk failure scenarios for a
2258	  N-disk array.  Recovery is performed with the asynchronous
2259	  raid6 recovery routines, and will optionally use an offload
2260	  engine if one is available.
2261
2262	  If unsure, say N.
2263
2264config TEST_HEXDUMP
2265	tristate "Test functions located in the hexdump module at runtime"
2266
2267config STRING_SELFTEST
2268	tristate "Test string functions at runtime"
2269
2270config TEST_STRING_HELPERS
2271	tristate "Test functions located in the string_helpers module at runtime"
2272
2273config TEST_KSTRTOX
2274	tristate "Test kstrto*() family of functions at runtime"
2275
2276config TEST_PRINTF
2277	tristate "Test printf() family of functions at runtime"
2278
2279config TEST_SCANF
2280	tristate "Test scanf() family of functions at runtime"
2281
2282config TEST_BITMAP
2283	tristate "Test bitmap_*() family of functions at runtime"
2284	help
2285	  Enable this option to test the bitmap functions at boot.
2286
2287	  If unsure, say N.
2288
2289config TEST_UUID
2290	tristate "Test functions located in the uuid module at runtime"
2291
2292config TEST_XARRAY
2293	tristate "Test the XArray code at runtime"
2294
2295config TEST_MAPLE_TREE
2296	depends on DEBUG_KERNEL
2297	select DEBUG_MAPLE_TREE
2298	tristate "Test the Maple Tree code at runtime"
2299
2300config TEST_RHASHTABLE
2301	tristate "Perform selftest on resizable hash table"
2302	help
2303	  Enable this option to test the rhashtable functions at boot.
2304
2305	  If unsure, say N.
2306
2307config TEST_IDA
2308	tristate "Perform selftest on IDA functions"
2309
2310config TEST_PARMAN
2311	tristate "Perform selftest on priority array manager"
2312	depends on PARMAN
2313	help
2314	  Enable this option to test priority array manager on boot
2315	  (or module load).
2316
2317	  If unsure, say N.
2318
2319config TEST_IRQ_TIMINGS
2320	bool "IRQ timings selftest"
2321	depends on IRQ_TIMINGS
2322	help
2323	  Enable this option to test the irq timings code on boot.
2324
2325	  If unsure, say N.
2326
2327config TEST_LKM
2328	tristate "Test module loading with 'hello world' module"
2329	depends on m
2330	help
2331	  This builds the "test_module" module that emits "Hello, world"
2332	  on printk when loaded. It is designed to be used for basic
2333	  evaluation of the module loading subsystem (for example when
2334	  validating module verification). It lacks any extra dependencies,
2335	  and will not normally be loaded by the system unless explicitly
2336	  requested by name.
2337
2338	  If unsure, say N.
2339
2340config TEST_BITOPS
2341	tristate "Test module for compilation of bitops operations"
2342	depends on m
2343	help
2344	  This builds the "test_bitops" module that is much like the
2345	  TEST_LKM module except that it does a basic exercise of the
2346	  set/clear_bit macros and get_count_order/long to make sure there are
2347	  no compiler warnings from C=1 sparse checker or -Wextra
2348	  compilations. It has no dependencies and doesn't run or load unless
2349	  explicitly requested by name.  for example: modprobe test_bitops.
2350
2351	  If unsure, say N.
2352
2353config TEST_VMALLOC
2354	tristate "Test module for stress/performance analysis of vmalloc allocator"
2355	default n
2356       depends on MMU
2357	depends on m
2358	help
2359	  This builds the "test_vmalloc" module that should be used for
2360	  stress and performance analysis. So, any new change for vmalloc
2361	  subsystem can be evaluated from performance and stability point
2362	  of view.
2363
2364	  If unsure, say N.
2365
2366config TEST_USER_COPY
2367	tristate "Test user/kernel boundary protections"
2368	depends on m
2369	help
2370	  This builds the "test_user_copy" module that runs sanity checks
2371	  on the copy_to/from_user infrastructure, making sure basic
2372	  user/kernel boundary testing is working. If it fails to load,
2373	  a regression has been detected in the user/kernel memory boundary
2374	  protections.
2375
2376	  If unsure, say N.
2377
2378config TEST_BPF
2379	tristate "Test BPF filter functionality"
2380	depends on m && NET
2381	help
2382	  This builds the "test_bpf" module that runs various test vectors
2383	  against the BPF interpreter or BPF JIT compiler depending on the
2384	  current setting. This is in particular useful for BPF JIT compiler
2385	  development, but also to run regression tests against changes in
2386	  the interpreter code. It also enables test stubs for eBPF maps and
2387	  verifier used by user space verifier testsuite.
2388
2389	  If unsure, say N.
2390
2391config TEST_BLACKHOLE_DEV
2392	tristate "Test blackhole netdev functionality"
2393	depends on m && NET
2394	help
2395	  This builds the "test_blackhole_dev" module that validates the
2396	  data path through this blackhole netdev.
2397
2398	  If unsure, say N.
2399
2400config FIND_BIT_BENCHMARK
2401	tristate "Test find_bit functions"
2402	help
2403	  This builds the "test_find_bit" module that measure find_*_bit()
2404	  functions performance.
2405
2406	  If unsure, say N.
2407
2408config TEST_FIRMWARE
2409	tristate "Test firmware loading via userspace interface"
2410	depends on FW_LOADER
2411	help
2412	  This builds the "test_firmware" module that creates a userspace
2413	  interface for testing firmware loading. This can be used to
2414	  control the triggering of firmware loading without needing an
2415	  actual firmware-using device. The contents can be rechecked by
2416	  userspace.
2417
2418	  If unsure, say N.
2419
2420config TEST_SYSCTL
2421	tristate "sysctl test driver"
2422	depends on PROC_SYSCTL
2423	help
2424	  This builds the "test_sysctl" module. This driver enables to test the
2425	  proc sysctl interfaces available to drivers safely without affecting
2426	  production knobs which might alter system functionality.
2427
2428	  If unsure, say N.
2429
2430config BITFIELD_KUNIT
2431	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2432	depends on KUNIT
2433	default KUNIT_ALL_TESTS
2434	help
2435	  Enable this option to test the bitfield functions at boot.
2436
2437	  KUnit tests run during boot and output the results to the debug log
2438	  in TAP format (http://testanything.org/). Only useful for kernel devs
2439	  running the KUnit test harness, and not intended for inclusion into a
2440	  production build.
2441
2442	  For more information on KUnit and unit tests in general please refer
2443	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2444
2445	  If unsure, say N.
2446
2447config HASH_KUNIT_TEST
2448	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2449	depends on KUNIT
2450	default KUNIT_ALL_TESTS
2451	help
2452	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2453	  integer (<linux/hash.h>) hash functions on boot.
2454
2455	  KUnit tests run during boot and output the results to the debug log
2456	  in TAP format (https://testanything.org/). Only useful for kernel devs
2457	  running the KUnit test harness, and not intended for inclusion into a
2458	  production build.
2459
2460	  For more information on KUnit and unit tests in general please refer
2461	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2462
2463	  This is intended to help people writing architecture-specific
2464	  optimized versions. If unsure, say N.
2465
2466config RESOURCE_KUNIT_TEST
2467	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2468	depends on KUNIT
2469	default KUNIT_ALL_TESTS
2470	help
2471	  This builds the resource API unit test.
2472	  Tests the logic of API provided by resource.c and ioport.h.
2473	  For more information on KUnit and unit tests in general please refer
2474	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2475
2476	  If unsure, say N.
2477
2478config SYSCTL_KUNIT_TEST
2479	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2480	depends on KUNIT
2481	default KUNIT_ALL_TESTS
2482	help
2483	  This builds the proc sysctl unit test, which runs on boot.
2484	  Tests the API contract and implementation correctness of sysctl.
2485	  For more information on KUnit and unit tests in general please refer
2486	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2487
2488	  If unsure, say N.
2489
2490config LIST_KUNIT_TEST
2491	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2492	depends on KUNIT
2493	default KUNIT_ALL_TESTS
2494	help
2495	  This builds the linked list KUnit test suite.
2496	  It tests that the API and basic functionality of the list_head type
2497	  and associated macros.
2498
2499	  KUnit tests run during boot and output the results to the debug log
2500	  in TAP format (https://testanything.org/). Only useful for kernel devs
2501	  running the KUnit test harness, and not intended for inclusion into a
2502	  production build.
2503
2504	  For more information on KUnit and unit tests in general please refer
2505	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2506
2507	  If unsure, say N.
2508
2509config LINEAR_RANGES_TEST
2510	tristate "KUnit test for linear_ranges"
2511	depends on KUNIT
2512	select LINEAR_RANGES
2513	help
2514	  This builds the linear_ranges unit test, which runs on boot.
2515	  Tests the linear_ranges logic correctness.
2516	  For more information on KUnit and unit tests in general please refer
2517	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2518
2519	  If unsure, say N.
2520
2521config CMDLINE_KUNIT_TEST
2522	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2523	depends on KUNIT
2524	default KUNIT_ALL_TESTS
2525	help
2526	  This builds the cmdline API unit test.
2527	  Tests the logic of API provided by cmdline.c.
2528	  For more information on KUnit and unit tests in general please refer
2529	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2530
2531	  If unsure, say N.
2532
2533config BITS_TEST
2534	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2535	depends on KUNIT
2536	default KUNIT_ALL_TESTS
2537	help
2538	  This builds the bits unit test.
2539	  Tests the logic of macros defined in bits.h.
2540	  For more information on KUnit and unit tests in general please refer
2541	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2542
2543	  If unsure, say N.
2544
2545config SLUB_KUNIT_TEST
2546	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2547	depends on SLUB_DEBUG && KUNIT
2548	default KUNIT_ALL_TESTS
2549	help
2550	  This builds SLUB allocator unit test.
2551	  Tests SLUB cache debugging functionality.
2552	  For more information on KUnit and unit tests in general please refer
2553	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2554
2555	  If unsure, say N.
2556
2557config RATIONAL_KUNIT_TEST
2558	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2559	depends on KUNIT && RATIONAL
2560	default KUNIT_ALL_TESTS
2561	help
2562	  This builds the rational math unit test.
2563	  For more information on KUnit and unit tests in general please refer
2564	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2565
2566	  If unsure, say N.
2567
2568config MEMCPY_KUNIT_TEST
2569	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2570	depends on KUNIT
2571	default KUNIT_ALL_TESTS
2572	help
2573	  Builds unit tests for memcpy(), memmove(), and memset() functions.
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 MEMCPY_SLOW_KUNIT_TEST
2580	bool "Include exhaustive memcpy tests"
2581	depends on MEMCPY_KUNIT_TEST
2582	default y
2583	help
2584	  Some memcpy tests are quite exhaustive in checking for overlaps
2585	  and bit ranges. These can be very slow, so they are split out
2586	  as a separate config, in case they need to be disabled.
2587
2588config IS_SIGNED_TYPE_KUNIT_TEST
2589	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2590	depends on KUNIT
2591	default KUNIT_ALL_TESTS
2592	help
2593	  Builds unit tests for the is_signed_type() macro.
2594
2595	  For more information on KUnit and unit tests in general please refer
2596	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2597
2598	  If unsure, say N.
2599
2600config OVERFLOW_KUNIT_TEST
2601	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2602	depends on KUNIT
2603	default KUNIT_ALL_TESTS
2604	help
2605	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2606	  related functions.
2607
2608	  For more information on KUnit and unit tests in general please refer
2609	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2610
2611	  If unsure, say N.
2612
2613config STACKINIT_KUNIT_TEST
2614	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2615	depends on KUNIT
2616	default KUNIT_ALL_TESTS
2617	help
2618	  Test if the kernel is zero-initializing stack variables and
2619	  padding. Coverage is controlled by compiler flags,
2620	  CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2621	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2622	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2623
2624config FORTIFY_KUNIT_TEST
2625	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2626	depends on KUNIT && FORTIFY_SOURCE
2627	default KUNIT_ALL_TESTS
2628	help
2629	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2630	  by the str*() and mem*() family of functions. For testing runtime
2631	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2632
2633config HW_BREAKPOINT_KUNIT_TEST
2634	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2635	depends on HAVE_HW_BREAKPOINT
2636	depends on KUNIT=y
2637	default KUNIT_ALL_TESTS
2638	help
2639	  Tests for hw_breakpoint constraints accounting.
2640
2641	  If unsure, say N.
2642
2643config STRSCPY_KUNIT_TEST
2644	tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2645	depends on KUNIT
2646	default KUNIT_ALL_TESTS
2647
2648config SIPHASH_KUNIT_TEST
2649	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2650	depends on KUNIT
2651	default KUNIT_ALL_TESTS
2652	help
2653	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2654	  functions on boot (or module load).
2655
2656	  This is intended to help people writing architecture-specific
2657	  optimized versions.  If unsure, say N.
2658
2659config TEST_UDELAY
2660	tristate "udelay test driver"
2661	help
2662	  This builds the "udelay_test" module that helps to make sure
2663	  that udelay() is working properly.
2664
2665	  If unsure, say N.
2666
2667config TEST_STATIC_KEYS
2668	tristate "Test static keys"
2669	depends on m
2670	help
2671	  Test the static key interfaces.
2672
2673	  If unsure, say N.
2674
2675config TEST_DYNAMIC_DEBUG
2676	tristate "Test DYNAMIC_DEBUG"
2677	depends on DYNAMIC_DEBUG
2678	help
2679	  This module registers a tracer callback to count enabled
2680	  pr_debugs in a 'do_debugging' function, then alters their
2681	  enablements, calls the function, and compares counts.
2682
2683	  If unsure, say N.
2684
2685config TEST_KMOD
2686	tristate "kmod stress tester"
2687	depends on m
2688	depends on NETDEVICES && NET_CORE && INET # for TUN
2689	depends on BLOCK
2690	depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2691	select TEST_LKM
2692	select XFS_FS
2693	select TUN
2694	select BTRFS_FS
2695	help
2696	  Test the kernel's module loading mechanism: kmod. kmod implements
2697	  support to load modules using the Linux kernel's usermode helper.
2698	  This test provides a series of tests against kmod.
2699
2700	  Although technically you can either build test_kmod as a module or
2701	  into the kernel we disallow building it into the kernel since
2702	  it stress tests request_module() and this will very likely cause
2703	  some issues by taking over precious threads available from other
2704	  module load requests, ultimately this could be fatal.
2705
2706	  To run tests run:
2707
2708	  tools/testing/selftests/kmod/kmod.sh --help
2709
2710	  If unsure, say N.
2711
2712config TEST_DEBUG_VIRTUAL
2713	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2714	depends on DEBUG_VIRTUAL
2715	help
2716	  Test the kernel's ability to detect incorrect calls to
2717	  virt_to_phys() done against the non-linear part of the
2718	  kernel's virtual address map.
2719
2720	  If unsure, say N.
2721
2722config TEST_MEMCAT_P
2723	tristate "Test memcat_p() helper function"
2724	help
2725	  Test the memcat_p() helper for correctly merging two
2726	  pointer arrays together.
2727
2728	  If unsure, say N.
2729
2730config TEST_LIVEPATCH
2731	tristate "Test livepatching"
2732	default n
2733	depends on DYNAMIC_DEBUG
2734	depends on LIVEPATCH
2735	depends on m
2736	help
2737	  Test kernel livepatching features for correctness.  The tests will
2738	  load test modules that will be livepatched in various scenarios.
2739
2740	  To run all the livepatching tests:
2741
2742	  make -C tools/testing/selftests TARGETS=livepatch run_tests
2743
2744	  Alternatively, individual tests may be invoked:
2745
2746	  tools/testing/selftests/livepatch/test-callbacks.sh
2747	  tools/testing/selftests/livepatch/test-livepatch.sh
2748	  tools/testing/selftests/livepatch/test-shadow-vars.sh
2749
2750	  If unsure, say N.
2751
2752config TEST_OBJAGG
2753	tristate "Perform selftest on object aggreration manager"
2754	default n
2755	depends on OBJAGG
2756	help
2757	  Enable this option to test object aggregation manager on boot
2758	  (or module load).
2759
2760config TEST_MEMINIT
2761	tristate "Test heap/page initialization"
2762	help
2763	  Test if the kernel is zero-initializing heap and page allocations.
2764	  This can be useful to test init_on_alloc and init_on_free features.
2765
2766	  If unsure, say N.
2767
2768config TEST_HMM
2769	tristate "Test HMM (Heterogeneous Memory Management)"
2770	depends on TRANSPARENT_HUGEPAGE
2771	depends on DEVICE_PRIVATE
2772	select HMM_MIRROR
2773	select MMU_NOTIFIER
2774	help
2775	  This is a pseudo device driver solely for testing HMM.
2776	  Say M here if you want to build the HMM test module.
2777	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2778
2779	  If unsure, say N.
2780
2781config TEST_FREE_PAGES
2782	tristate "Test freeing pages"
2783	help
2784	  Test that a memory leak does not occur due to a race between
2785	  freeing a block of pages and a speculative page reference.
2786	  Loading this module is safe if your kernel has the bug fixed.
2787	  If the bug is not fixed, it will leak gigabytes of memory and
2788	  probably OOM your system.
2789
2790config TEST_FPU
2791	tristate "Test floating point operations in kernel space"
2792	depends on X86 && !KCOV_INSTRUMENT_ALL
2793	help
2794	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2795	  which will trigger a sequence of floating point operations. This is used
2796	  for self-testing floating point control register setting in
2797	  kernel_fpu_begin().
2798
2799	  If unsure, say N.
2800
2801config TEST_CLOCKSOURCE_WATCHDOG
2802	tristate "Test clocksource watchdog in kernel space"
2803	depends on CLOCKSOURCE_WATCHDOG
2804	help
2805	  Enable this option to create a kernel module that will trigger
2806	  a test of the clocksource watchdog.  This module may be loaded
2807	  via modprobe or insmod in which case it will run upon being
2808	  loaded, or it may be built in, in which case it will run
2809	  shortly after boot.
2810
2811	  If unsure, say N.
2812
2813endif # RUNTIME_TESTING_MENU
2814
2815config ARCH_USE_MEMTEST
2816	bool
2817	help
2818	  An architecture should select this when it uses early_memtest()
2819	  during boot process.
2820
2821config MEMTEST
2822	bool "Memtest"
2823	depends on ARCH_USE_MEMTEST
2824	help
2825	  This option adds a kernel parameter 'memtest', which allows memtest
2826	  to be set and executed.
2827	        memtest=0, mean disabled; -- default
2828	        memtest=1, mean do 1 test pattern;
2829	        ...
2830	        memtest=17, mean do 17 test patterns.
2831	  If you are unsure how to answer this question, answer N.
2832
2833
2834
2835config HYPERV_TESTING
2836	bool "Microsoft Hyper-V driver testing"
2837	default n
2838	depends on HYPERV && DEBUG_FS
2839	help
2840	  Select this option to enable Hyper-V vmbus testing.
2841
2842endmenu # "Kernel Testing and Coverage"
2843
2844menu "Rust hacking"
2845
2846config RUST_DEBUG_ASSERTIONS
2847	bool "Debug assertions"
2848	depends on RUST
2849	help
2850	  Enables rustc's `-Cdebug-assertions` codegen option.
2851
2852	  This flag lets you turn `cfg(debug_assertions)` conditional
2853	  compilation on or off. This can be used to enable extra debugging
2854	  code in development but not in production. For example, it controls
2855	  the behavior of the standard library's `debug_assert!` macro.
2856
2857	  Note that this will apply to all Rust code, including `core`.
2858
2859	  If unsure, say N.
2860
2861config RUST_OVERFLOW_CHECKS
2862	bool "Overflow checks"
2863	default y
2864	depends on RUST
2865	help
2866	  Enables rustc's `-Coverflow-checks` codegen option.
2867
2868	  This flag allows you to control the behavior of runtime integer
2869	  overflow. When overflow-checks are enabled, a Rust panic will occur
2870	  on overflow.
2871
2872	  Note that this will apply to all Rust code, including `core`.
2873
2874	  If unsure, say Y.
2875
2876config RUST_BUILD_ASSERT_ALLOW
2877	bool "Allow unoptimized build-time assertions"
2878	depends on RUST
2879	help
2880	  Controls how are `build_error!` and `build_assert!` handled during build.
2881
2882	  If calls to them exist in the binary, it may indicate a violated invariant
2883	  or that the optimizer failed to verify the invariant during compilation.
2884
2885	  This should not happen, thus by default the build is aborted. However,
2886	  as an escape hatch, you can choose Y here to ignore them during build
2887	  and let the check be carried at runtime (with `panic!` being called if
2888	  the check fails).
2889
2890	  If unsure, say N.
2891
2892endmenu # "Rust"
2893
2894source "Documentation/Kconfig"
2895
2896endmenu # Kernel hacking
2897