xref: /openbmc/linux/lib/Kconfig.debug (revision 6486a57f)
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 NMI_CHECK_CPU
1566	bool "Debugging for CPUs failing to respond to backtrace requests"
1567	depends on DEBUG_KERNEL
1568	depends on X86
1569	default n
1570	help
1571	  Enables debug prints when a CPU fails to respond to a given
1572	  backtrace NMI.  These prints provide some reasons why a CPU
1573	  might legitimately be failing to respond, for example, if it
1574	  is offline of if ignore_nmis is set.
1575
1576config DEBUG_IRQFLAGS
1577	bool "Debug IRQ flag manipulation"
1578	help
1579	  Enables checks for potentially unsafe enabling or disabling of
1580	  interrupts, such as calling raw_local_irq_restore() when interrupts
1581	  are enabled.
1582
1583config STACKTRACE
1584	bool "Stack backtrace support"
1585	depends on STACKTRACE_SUPPORT
1586	help
1587	  This option causes the kernel to create a /proc/pid/stack for
1588	  every process, showing its current stack trace.
1589	  It is also used by various kernel debugging features that require
1590	  stack trace generation.
1591
1592config WARN_ALL_UNSEEDED_RANDOM
1593	bool "Warn for all uses of unseeded randomness"
1594	default n
1595	help
1596	  Some parts of the kernel contain bugs relating to their use of
1597	  cryptographically secure random numbers before it's actually possible
1598	  to generate those numbers securely. This setting ensures that these
1599	  flaws don't go unnoticed, by enabling a message, should this ever
1600	  occur. This will allow people with obscure setups to know when things
1601	  are going wrong, so that they might contact developers about fixing
1602	  it.
1603
1604	  Unfortunately, on some models of some architectures getting
1605	  a fully seeded CRNG is extremely difficult, and so this can
1606	  result in dmesg getting spammed for a surprisingly long
1607	  time.  This is really bad from a security perspective, and
1608	  so architecture maintainers really need to do what they can
1609	  to get the CRNG seeded sooner after the system is booted.
1610	  However, since users cannot do anything actionable to
1611	  address this, by default this option is disabled.
1612
1613	  Say Y here if you want to receive warnings for all uses of
1614	  unseeded randomness.  This will be of use primarily for
1615	  those developers interested in improving the security of
1616	  Linux kernels running on their architecture (or
1617	  subarchitecture).
1618
1619config DEBUG_KOBJECT
1620	bool "kobject debugging"
1621	depends on DEBUG_KERNEL
1622	help
1623	  If you say Y here, some extra kobject debugging messages will be sent
1624	  to the syslog.
1625
1626config DEBUG_KOBJECT_RELEASE
1627	bool "kobject release debugging"
1628	depends on DEBUG_OBJECTS_TIMERS
1629	help
1630	  kobjects are reference counted objects.  This means that their
1631	  last reference count put is not predictable, and the kobject can
1632	  live on past the point at which a driver decides to drop its
1633	  initial reference to the kobject gained on allocation.  An
1634	  example of this would be a struct device which has just been
1635	  unregistered.
1636
1637	  However, some buggy drivers assume that after such an operation,
1638	  the memory backing the kobject can be immediately freed.  This
1639	  goes completely against the principles of a refcounted object.
1640
1641	  If you say Y here, the kernel will delay the release of kobjects
1642	  on the last reference count to improve the visibility of this
1643	  kind of kobject release bug.
1644
1645config HAVE_DEBUG_BUGVERBOSE
1646	bool
1647
1648menu "Debug kernel data structures"
1649
1650config DEBUG_LIST
1651	bool "Debug linked list manipulation"
1652	depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1653	help
1654	  Enable this to turn on extended checks in the linked-list
1655	  walking routines.
1656
1657	  If unsure, say N.
1658
1659config DEBUG_PLIST
1660	bool "Debug priority linked list manipulation"
1661	depends on DEBUG_KERNEL
1662	help
1663	  Enable this to turn on extended checks in the priority-ordered
1664	  linked-list (plist) walking routines.  This checks the entire
1665	  list multiple times during each manipulation.
1666
1667	  If unsure, say N.
1668
1669config DEBUG_SG
1670	bool "Debug SG table operations"
1671	depends on DEBUG_KERNEL
1672	help
1673	  Enable this to turn on checks on scatter-gather tables. This can
1674	  help find problems with drivers that do not properly initialize
1675	  their sg tables.
1676
1677	  If unsure, say N.
1678
1679config DEBUG_NOTIFIERS
1680	bool "Debug notifier call chains"
1681	depends on DEBUG_KERNEL
1682	help
1683	  Enable this to turn on sanity checking for notifier call chains.
1684	  This is most useful for kernel developers to make sure that
1685	  modules properly unregister themselves from notifier chains.
1686	  This is a relatively cheap check but if you care about maximum
1687	  performance, say N.
1688
1689config BUG_ON_DATA_CORRUPTION
1690	bool "Trigger a BUG when data corruption is detected"
1691	select DEBUG_LIST
1692	help
1693	  Select this option if the kernel should BUG when it encounters
1694	  data corruption in kernel memory structures when they get checked
1695	  for validity.
1696
1697	  If unsure, say N.
1698
1699config DEBUG_MAPLE_TREE
1700	bool "Debug maple trees"
1701	depends on DEBUG_KERNEL
1702	help
1703	  Enable maple tree debugging information and extra validations.
1704
1705	  If unsure, say N.
1706
1707endmenu
1708
1709config DEBUG_CREDENTIALS
1710	bool "Debug credential management"
1711	depends on DEBUG_KERNEL
1712	help
1713	  Enable this to turn on some debug checking for credential
1714	  management.  The additional code keeps track of the number of
1715	  pointers from task_structs to any given cred struct, and checks to
1716	  see that this number never exceeds the usage count of the cred
1717	  struct.
1718
1719	  Furthermore, if SELinux is enabled, this also checks that the
1720	  security pointer in the cred struct is never seen to be invalid.
1721
1722	  If unsure, say N.
1723
1724source "kernel/rcu/Kconfig.debug"
1725
1726config DEBUG_WQ_FORCE_RR_CPU
1727	bool "Force round-robin CPU selection for unbound work items"
1728	depends on DEBUG_KERNEL
1729	default n
1730	help
1731	  Workqueue used to implicitly guarantee that work items queued
1732	  without explicit CPU specified are put on the local CPU.  This
1733	  guarantee is no longer true and while local CPU is still
1734	  preferred work items may be put on foreign CPUs.  Kernel
1735	  parameter "workqueue.debug_force_rr_cpu" is added to force
1736	  round-robin CPU selection to flush out usages which depend on the
1737	  now broken guarantee.  This config option enables the debug
1738	  feature by default.  When enabled, memory and cache locality will
1739	  be impacted.
1740
1741config CPU_HOTPLUG_STATE_CONTROL
1742	bool "Enable CPU hotplug state control"
1743	depends on DEBUG_KERNEL
1744	depends on HOTPLUG_CPU
1745	default n
1746	help
1747	  Allows to write steps between "offline" and "online" to the CPUs
1748	  sysfs target file so states can be stepped granular. This is a debug
1749	  option for now as the hotplug machinery cannot be stopped and
1750	  restarted at arbitrary points yet.
1751
1752	  Say N if your are unsure.
1753
1754config LATENCYTOP
1755	bool "Latency measuring infrastructure"
1756	depends on DEBUG_KERNEL
1757	depends on STACKTRACE_SUPPORT
1758	depends on PROC_FS
1759	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1760	select KALLSYMS
1761	select KALLSYMS_ALL
1762	select STACKTRACE
1763	select SCHEDSTATS
1764	help
1765	  Enable this option if you want to use the LatencyTOP tool
1766	  to find out which userspace is blocking on what kernel operations.
1767
1768config DEBUG_CGROUP_REF
1769	bool "Disable inlining of cgroup css reference count functions"
1770	depends on DEBUG_KERNEL
1771	depends on CGROUPS
1772	depends on KPROBES
1773	default n
1774	help
1775	  Force cgroup css reference count functions to not be inlined so
1776	  that they can be kprobed for debugging.
1777
1778source "kernel/trace/Kconfig"
1779
1780config PROVIDE_OHCI1394_DMA_INIT
1781	bool "Remote debugging over FireWire early on boot"
1782	depends on PCI && X86
1783	help
1784	  If you want to debug problems which hang or crash the kernel early
1785	  on boot and the crashing machine has a FireWire port, you can use
1786	  this feature to remotely access the memory of the crashed machine
1787	  over FireWire. This employs remote DMA as part of the OHCI1394
1788	  specification which is now the standard for FireWire controllers.
1789
1790	  With remote DMA, you can monitor the printk buffer remotely using
1791	  firescope and access all memory below 4GB using fireproxy from gdb.
1792	  Even controlling a kernel debugger is possible using remote DMA.
1793
1794	  Usage:
1795
1796	  If ohci1394_dma=early is used as boot parameter, it will initialize
1797	  all OHCI1394 controllers which are found in the PCI config space.
1798
1799	  As all changes to the FireWire bus such as enabling and disabling
1800	  devices cause a bus reset and thereby disable remote DMA for all
1801	  devices, be sure to have the cable plugged and FireWire enabled on
1802	  the debugging host before booting the debug target for debugging.
1803
1804	  This code (~1k) is freed after boot. By then, the firewire stack
1805	  in charge of the OHCI-1394 controllers should be used instead.
1806
1807	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1808
1809source "samples/Kconfig"
1810
1811config ARCH_HAS_DEVMEM_IS_ALLOWED
1812	bool
1813
1814config STRICT_DEVMEM
1815	bool "Filter access to /dev/mem"
1816	depends on MMU && DEVMEM
1817	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1818	default y if PPC || X86 || ARM64
1819	help
1820	  If this option is disabled, you allow userspace (root) access to all
1821	  of memory, including kernel and userspace memory. Accidental
1822	  access to this is obviously disastrous, but specific access can
1823	  be used by people debugging the kernel. Note that with PAT support
1824	  enabled, even in this case there are restrictions on /dev/mem
1825	  use due to the cache aliasing requirements.
1826
1827	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1828	  file only allows userspace access to PCI space and the BIOS code and
1829	  data regions.  This is sufficient for dosemu and X and all common
1830	  users of /dev/mem.
1831
1832	  If in doubt, say Y.
1833
1834config IO_STRICT_DEVMEM
1835	bool "Filter I/O access to /dev/mem"
1836	depends on STRICT_DEVMEM
1837	help
1838	  If this option is disabled, you allow userspace (root) access to all
1839	  io-memory regardless of whether a driver is actively using that
1840	  range.  Accidental access to this is obviously disastrous, but
1841	  specific access can be used by people debugging kernel drivers.
1842
1843	  If this option is switched on, the /dev/mem file only allows
1844	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1845	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1846	  if the driver using a given range cannot be disabled.
1847
1848	  If in doubt, say Y.
1849
1850menu "$(SRCARCH) Debugging"
1851
1852source "arch/$(SRCARCH)/Kconfig.debug"
1853
1854endmenu
1855
1856menu "Kernel Testing and Coverage"
1857
1858source "lib/kunit/Kconfig"
1859
1860config NOTIFIER_ERROR_INJECTION
1861	tristate "Notifier error injection"
1862	depends on DEBUG_KERNEL
1863	select DEBUG_FS
1864	help
1865	  This option provides the ability to inject artificial errors to
1866	  specified notifier chain callbacks. It is useful to test the error
1867	  handling of notifier call chain failures.
1868
1869	  Say N if unsure.
1870
1871config PM_NOTIFIER_ERROR_INJECT
1872	tristate "PM notifier error injection module"
1873	depends on PM && NOTIFIER_ERROR_INJECTION
1874	default m if PM_DEBUG
1875	help
1876	  This option provides the ability to inject artificial errors to
1877	  PM notifier chain callbacks.  It is controlled through debugfs
1878	  interface /sys/kernel/debug/notifier-error-inject/pm
1879
1880	  If the notifier call chain should be failed with some events
1881	  notified, write the error code to "actions/<notifier event>/error".
1882
1883	  Example: Inject PM suspend error (-12 = -ENOMEM)
1884
1885	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1886	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1887	  # echo mem > /sys/power/state
1888	  bash: echo: write error: Cannot allocate memory
1889
1890	  To compile this code as a module, choose M here: the module will
1891	  be called pm-notifier-error-inject.
1892
1893	  If unsure, say N.
1894
1895config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1896	tristate "OF reconfig notifier error injection module"
1897	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1898	help
1899	  This option provides the ability to inject artificial errors to
1900	  OF reconfig notifier chain callbacks.  It is controlled
1901	  through debugfs interface under
1902	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1903
1904	  If the notifier call chain should be failed with some events
1905	  notified, write the error code to "actions/<notifier event>/error".
1906
1907	  To compile this code as a module, choose M here: the module will
1908	  be called of-reconfig-notifier-error-inject.
1909
1910	  If unsure, say N.
1911
1912config NETDEV_NOTIFIER_ERROR_INJECT
1913	tristate "Netdev notifier error injection module"
1914	depends on NET && NOTIFIER_ERROR_INJECTION
1915	help
1916	  This option provides the ability to inject artificial errors to
1917	  netdevice notifier chain callbacks.  It is controlled through debugfs
1918	  interface /sys/kernel/debug/notifier-error-inject/netdev
1919
1920	  If the notifier call chain should be failed with some events
1921	  notified, write the error code to "actions/<notifier event>/error".
1922
1923	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
1924
1925	  # cd /sys/kernel/debug/notifier-error-inject/netdev
1926	  # echo -22 > actions/NETDEV_CHANGEMTU/error
1927	  # ip link set eth0 mtu 1024
1928	  RTNETLINK answers: Invalid argument
1929
1930	  To compile this code as a module, choose M here: the module will
1931	  be called netdev-notifier-error-inject.
1932
1933	  If unsure, say N.
1934
1935config FUNCTION_ERROR_INJECTION
1936	bool "Fault-injections of functions"
1937	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1938	help
1939	  Add fault injections into various functions that are annotated with
1940	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1941	  value of these functions. This is useful to test error paths of code.
1942
1943	  If unsure, say N
1944
1945config FAULT_INJECTION
1946	bool "Fault-injection framework"
1947	depends on DEBUG_KERNEL
1948	help
1949	  Provide fault-injection framework.
1950	  For more details, see Documentation/fault-injection/.
1951
1952config FAILSLAB
1953	bool "Fault-injection capability for kmalloc"
1954	depends on FAULT_INJECTION
1955	depends on SLAB || SLUB
1956	help
1957	  Provide fault-injection capability for kmalloc.
1958
1959config FAIL_PAGE_ALLOC
1960	bool "Fault-injection capability for alloc_pages()"
1961	depends on FAULT_INJECTION
1962	help
1963	  Provide fault-injection capability for alloc_pages().
1964
1965config FAULT_INJECTION_USERCOPY
1966	bool "Fault injection capability for usercopy functions"
1967	depends on FAULT_INJECTION
1968	help
1969	  Provides fault-injection capability to inject failures
1970	  in usercopy functions (copy_from_user(), get_user(), ...).
1971
1972config FAIL_MAKE_REQUEST
1973	bool "Fault-injection capability for disk IO"
1974	depends on FAULT_INJECTION && BLOCK
1975	help
1976	  Provide fault-injection capability for disk IO.
1977
1978config FAIL_IO_TIMEOUT
1979	bool "Fault-injection capability for faking disk interrupts"
1980	depends on FAULT_INJECTION && BLOCK
1981	help
1982	  Provide fault-injection capability on end IO handling. This
1983	  will make the block layer "forget" an interrupt as configured,
1984	  thus exercising the error handling.
1985
1986	  Only works with drivers that use the generic timeout handling,
1987	  for others it won't do anything.
1988
1989config FAIL_FUTEX
1990	bool "Fault-injection capability for futexes"
1991	select DEBUG_FS
1992	depends on FAULT_INJECTION && FUTEX
1993	help
1994	  Provide fault-injection capability for futexes.
1995
1996config FAULT_INJECTION_DEBUG_FS
1997	bool "Debugfs entries for fault-injection capabilities"
1998	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1999	help
2000	  Enable configuration of fault-injection capabilities via debugfs.
2001
2002config FAIL_FUNCTION
2003	bool "Fault-injection capability for functions"
2004	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2005	help
2006	  Provide function-based fault-injection capability.
2007	  This will allow you to override a specific function with a return
2008	  with given return value. As a result, function caller will see
2009	  an error value and have to handle it. This is useful to test the
2010	  error handling in various subsystems.
2011
2012config FAIL_MMC_REQUEST
2013	bool "Fault-injection capability for MMC IO"
2014	depends on FAULT_INJECTION_DEBUG_FS && MMC
2015	help
2016	  Provide fault-injection capability for MMC IO.
2017	  This will make the mmc core return data errors. This is
2018	  useful to test the error handling in the mmc block device
2019	  and to test how the mmc host driver handles retries from
2020	  the block device.
2021
2022config FAIL_SUNRPC
2023	bool "Fault-injection capability for SunRPC"
2024	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2025	help
2026	  Provide fault-injection capability for SunRPC and
2027	  its consumers.
2028
2029config FAULT_INJECTION_STACKTRACE_FILTER
2030	bool "stacktrace filter for fault-injection capabilities"
2031	depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2032	select STACKTRACE
2033	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2034	help
2035	  Provide stacktrace filter for fault-injection capabilities
2036
2037config ARCH_HAS_KCOV
2038	bool
2039	help
2040	  An architecture should select this when it can successfully
2041	  build and run with CONFIG_KCOV. This typically requires
2042	  disabling instrumentation for some early boot code.
2043
2044config CC_HAS_SANCOV_TRACE_PC
2045	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2046
2047
2048config KCOV
2049	bool "Code coverage for fuzzing"
2050	depends on ARCH_HAS_KCOV
2051	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2052	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2053		   GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2054	select DEBUG_FS
2055	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2056	select OBJTOOL if HAVE_NOINSTR_HACK
2057	help
2058	  KCOV exposes kernel code coverage information in a form suitable
2059	  for coverage-guided fuzzing (randomized testing).
2060
2061	  If RANDOMIZE_BASE is enabled, PC values will not be stable across
2062	  different machines and across reboots. If you need stable PC values,
2063	  disable RANDOMIZE_BASE.
2064
2065	  For more details, see Documentation/dev-tools/kcov.rst.
2066
2067config KCOV_ENABLE_COMPARISONS
2068	bool "Enable comparison operands collection by KCOV"
2069	depends on KCOV
2070	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2071	help
2072	  KCOV also exposes operands of every comparison in the instrumented
2073	  code along with operand sizes and PCs of the comparison instructions.
2074	  These operands can be used by fuzzing engines to improve the quality
2075	  of fuzzing coverage.
2076
2077config KCOV_INSTRUMENT_ALL
2078	bool "Instrument all code by default"
2079	depends on KCOV
2080	default y
2081	help
2082	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2083	  then you will want to instrument the whole kernel and you should
2084	  say y here. If you are doing more targeted fuzzing (like e.g.
2085	  filesystem fuzzing with AFL) then you will want to enable coverage
2086	  for more specific subsets of files, and should say n here.
2087
2088config KCOV_IRQ_AREA_SIZE
2089	hex "Size of interrupt coverage collection area in words"
2090	depends on KCOV
2091	default 0x40000
2092	help
2093	  KCOV uses preallocated per-cpu areas to collect coverage from
2094	  soft interrupts. This specifies the size of those areas in the
2095	  number of unsigned long words.
2096
2097menuconfig RUNTIME_TESTING_MENU
2098	bool "Runtime Testing"
2099	def_bool y
2100
2101if RUNTIME_TESTING_MENU
2102
2103config LKDTM
2104	tristate "Linux Kernel Dump Test Tool Module"
2105	depends on DEBUG_FS
2106	help
2107	This module enables testing of the different dumping mechanisms by
2108	inducing system failures at predefined crash points.
2109	If you don't need it: say N
2110	Choose M here to compile this code as a module. The module will be
2111	called lkdtm.
2112
2113	Documentation on how to use the module can be found in
2114	Documentation/fault-injection/provoke-crashes.rst
2115
2116config CPUMASK_KUNIT_TEST
2117	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2118	depends on KUNIT
2119	default KUNIT_ALL_TESTS
2120	help
2121	  Enable to turn on cpumask tests, running at boot or module load time.
2122
2123	  For more information on KUnit and unit tests in general, please refer
2124	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2125
2126	  If unsure, say N.
2127
2128config TEST_LIST_SORT
2129	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2130	depends on KUNIT
2131	default KUNIT_ALL_TESTS
2132	help
2133	  Enable this to turn on 'list_sort()' function test. This test is
2134	  executed only once during system boot (so affects only boot time),
2135	  or at module load time.
2136
2137	  If unsure, say N.
2138
2139config TEST_MIN_HEAP
2140	tristate "Min heap test"
2141	depends on DEBUG_KERNEL || m
2142	help
2143	  Enable this to turn on min heap function tests. This test is
2144	  executed only once during system boot (so affects only boot time),
2145	  or at module load time.
2146
2147	  If unsure, say N.
2148
2149config TEST_SORT
2150	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2151	depends on KUNIT
2152	default KUNIT_ALL_TESTS
2153	help
2154	  This option enables the self-test function of 'sort()' at boot,
2155	  or at module load time.
2156
2157	  If unsure, say N.
2158
2159config TEST_DIV64
2160	tristate "64bit/32bit division and modulo test"
2161	depends on DEBUG_KERNEL || m
2162	help
2163	  Enable this to turn on 'do_div()' function test. This test is
2164	  executed only once during system boot (so affects only boot time),
2165	  or at module load time.
2166
2167	  If unsure, say N.
2168
2169config KPROBES_SANITY_TEST
2170	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2171	depends on DEBUG_KERNEL
2172	depends on KPROBES
2173	depends on KUNIT
2174	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2175	default KUNIT_ALL_TESTS
2176	help
2177	  This option provides for testing basic kprobes functionality on
2178	  boot. Samples of kprobe and kretprobe are inserted and
2179	  verified for functionality.
2180
2181	  Say N if you are unsure.
2182
2183config FPROBE_SANITY_TEST
2184	bool "Self test for fprobe"
2185	depends on DEBUG_KERNEL
2186	depends on FPROBE
2187	depends on KUNIT=y
2188	help
2189	  This option will enable testing the fprobe when the system boot.
2190	  A series of tests are made to verify that the fprobe is functioning
2191	  properly.
2192
2193	  Say N if you are unsure.
2194
2195config BACKTRACE_SELF_TEST
2196	tristate "Self test for the backtrace code"
2197	depends on DEBUG_KERNEL
2198	help
2199	  This option provides a kernel module that can be used to test
2200	  the kernel stack backtrace code. This option is not useful
2201	  for distributions or general kernels, but only for kernel
2202	  developers working on architecture code.
2203
2204	  Note that if you want to also test saved backtraces, you will
2205	  have to enable STACKTRACE as well.
2206
2207	  Say N if you are unsure.
2208
2209config TEST_REF_TRACKER
2210	tristate "Self test for reference tracker"
2211	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2212	select REF_TRACKER
2213	help
2214	  This option provides a kernel module performing tests
2215	  using reference tracker infrastructure.
2216
2217	  Say N if you are unsure.
2218
2219config RBTREE_TEST
2220	tristate "Red-Black tree test"
2221	depends on DEBUG_KERNEL
2222	help
2223	  A benchmark measuring the performance of the rbtree library.
2224	  Also includes rbtree invariant checks.
2225
2226config REED_SOLOMON_TEST
2227	tristate "Reed-Solomon library test"
2228	depends on DEBUG_KERNEL || m
2229	select REED_SOLOMON
2230	select REED_SOLOMON_ENC16
2231	select REED_SOLOMON_DEC16
2232	help
2233	  This option enables the self-test function of rslib at boot,
2234	  or at module load time.
2235
2236	  If unsure, say N.
2237
2238config INTERVAL_TREE_TEST
2239	tristate "Interval tree test"
2240	depends on DEBUG_KERNEL
2241	select INTERVAL_TREE
2242	help
2243	  A benchmark measuring the performance of the interval tree library
2244
2245config PERCPU_TEST
2246	tristate "Per cpu operations test"
2247	depends on m && DEBUG_KERNEL
2248	help
2249	  Enable this option to build test module which validates per-cpu
2250	  operations.
2251
2252	  If unsure, say N.
2253
2254config ATOMIC64_SELFTEST
2255	tristate "Perform an atomic64_t self-test"
2256	help
2257	  Enable this option to test the atomic64_t functions at boot or
2258	  at module load time.
2259
2260	  If unsure, say N.
2261
2262config ASYNC_RAID6_TEST
2263	tristate "Self test for hardware accelerated raid6 recovery"
2264	depends on ASYNC_RAID6_RECOV
2265	select ASYNC_MEMCPY
2266	help
2267	  This is a one-shot self test that permutes through the
2268	  recovery of all the possible two disk failure scenarios for a
2269	  N-disk array.  Recovery is performed with the asynchronous
2270	  raid6 recovery routines, and will optionally use an offload
2271	  engine if one is available.
2272
2273	  If unsure, say N.
2274
2275config TEST_HEXDUMP
2276	tristate "Test functions located in the hexdump module at runtime"
2277
2278config STRING_SELFTEST
2279	tristate "Test string functions at runtime"
2280
2281config TEST_STRING_HELPERS
2282	tristate "Test functions located in the string_helpers module at runtime"
2283
2284config TEST_KSTRTOX
2285	tristate "Test kstrto*() family of functions at runtime"
2286
2287config TEST_PRINTF
2288	tristate "Test printf() family of functions at runtime"
2289
2290config TEST_SCANF
2291	tristate "Test scanf() family of functions at runtime"
2292
2293config TEST_BITMAP
2294	tristate "Test bitmap_*() family of functions at runtime"
2295	help
2296	  Enable this option to test the bitmap functions at boot.
2297
2298	  If unsure, say N.
2299
2300config TEST_UUID
2301	tristate "Test functions located in the uuid module at runtime"
2302
2303config TEST_XARRAY
2304	tristate "Test the XArray code at runtime"
2305
2306config TEST_MAPLE_TREE
2307	depends on DEBUG_KERNEL
2308	select DEBUG_MAPLE_TREE
2309	tristate "Test the Maple Tree code at runtime"
2310
2311config TEST_RHASHTABLE
2312	tristate "Perform selftest on resizable hash table"
2313	help
2314	  Enable this option to test the rhashtable functions at boot.
2315
2316	  If unsure, say N.
2317
2318config TEST_IDA
2319	tristate "Perform selftest on IDA functions"
2320
2321config TEST_PARMAN
2322	tristate "Perform selftest on priority array manager"
2323	depends on PARMAN
2324	help
2325	  Enable this option to test priority array manager on boot
2326	  (or module load).
2327
2328	  If unsure, say N.
2329
2330config TEST_IRQ_TIMINGS
2331	bool "IRQ timings selftest"
2332	depends on IRQ_TIMINGS
2333	help
2334	  Enable this option to test the irq timings code on boot.
2335
2336	  If unsure, say N.
2337
2338config TEST_LKM
2339	tristate "Test module loading with 'hello world' module"
2340	depends on m
2341	help
2342	  This builds the "test_module" module that emits "Hello, world"
2343	  on printk when loaded. It is designed to be used for basic
2344	  evaluation of the module loading subsystem (for example when
2345	  validating module verification). It lacks any extra dependencies,
2346	  and will not normally be loaded by the system unless explicitly
2347	  requested by name.
2348
2349	  If unsure, say N.
2350
2351config TEST_BITOPS
2352	tristate "Test module for compilation of bitops operations"
2353	depends on m
2354	help
2355	  This builds the "test_bitops" module that is much like the
2356	  TEST_LKM module except that it does a basic exercise of the
2357	  set/clear_bit macros and get_count_order/long to make sure there are
2358	  no compiler warnings from C=1 sparse checker or -Wextra
2359	  compilations. It has no dependencies and doesn't run or load unless
2360	  explicitly requested by name.  for example: modprobe test_bitops.
2361
2362	  If unsure, say N.
2363
2364config TEST_VMALLOC
2365	tristate "Test module for stress/performance analysis of vmalloc allocator"
2366	default n
2367       depends on MMU
2368	depends on m
2369	help
2370	  This builds the "test_vmalloc" module that should be used for
2371	  stress and performance analysis. So, any new change for vmalloc
2372	  subsystem can be evaluated from performance and stability point
2373	  of view.
2374
2375	  If unsure, say N.
2376
2377config TEST_USER_COPY
2378	tristate "Test user/kernel boundary protections"
2379	depends on m
2380	help
2381	  This builds the "test_user_copy" module that runs sanity checks
2382	  on the copy_to/from_user infrastructure, making sure basic
2383	  user/kernel boundary testing is working. If it fails to load,
2384	  a regression has been detected in the user/kernel memory boundary
2385	  protections.
2386
2387	  If unsure, say N.
2388
2389config TEST_BPF
2390	tristate "Test BPF filter functionality"
2391	depends on m && NET
2392	help
2393	  This builds the "test_bpf" module that runs various test vectors
2394	  against the BPF interpreter or BPF JIT compiler depending on the
2395	  current setting. This is in particular useful for BPF JIT compiler
2396	  development, but also to run regression tests against changes in
2397	  the interpreter code. It also enables test stubs for eBPF maps and
2398	  verifier used by user space verifier testsuite.
2399
2400	  If unsure, say N.
2401
2402config TEST_BLACKHOLE_DEV
2403	tristate "Test blackhole netdev functionality"
2404	depends on m && NET
2405	help
2406	  This builds the "test_blackhole_dev" module that validates the
2407	  data path through this blackhole netdev.
2408
2409	  If unsure, say N.
2410
2411config FIND_BIT_BENCHMARK
2412	tristate "Test find_bit functions"
2413	help
2414	  This builds the "test_find_bit" module that measure find_*_bit()
2415	  functions performance.
2416
2417	  If unsure, say N.
2418
2419config TEST_FIRMWARE
2420	tristate "Test firmware loading via userspace interface"
2421	depends on FW_LOADER
2422	help
2423	  This builds the "test_firmware" module that creates a userspace
2424	  interface for testing firmware loading. This can be used to
2425	  control the triggering of firmware loading without needing an
2426	  actual firmware-using device. The contents can be rechecked by
2427	  userspace.
2428
2429	  If unsure, say N.
2430
2431config TEST_SYSCTL
2432	tristate "sysctl test driver"
2433	depends on PROC_SYSCTL
2434	help
2435	  This builds the "test_sysctl" module. This driver enables to test the
2436	  proc sysctl interfaces available to drivers safely without affecting
2437	  production knobs which might alter system functionality.
2438
2439	  If unsure, say N.
2440
2441config BITFIELD_KUNIT
2442	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2443	depends on KUNIT
2444	default KUNIT_ALL_TESTS
2445	help
2446	  Enable this option to test the bitfield functions at boot.
2447
2448	  KUnit tests run during boot and output the results to the debug log
2449	  in TAP format (http://testanything.org/). Only useful for kernel devs
2450	  running the KUnit test harness, and not intended for inclusion into a
2451	  production build.
2452
2453	  For more information on KUnit and unit tests in general please refer
2454	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2455
2456	  If unsure, say N.
2457
2458config HASH_KUNIT_TEST
2459	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2460	depends on KUNIT
2461	default KUNIT_ALL_TESTS
2462	help
2463	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2464	  integer (<linux/hash.h>) hash functions on boot.
2465
2466	  KUnit tests run during boot and output the results to the debug log
2467	  in TAP format (https://testanything.org/). Only useful for kernel devs
2468	  running the KUnit test harness, and not intended for inclusion into a
2469	  production build.
2470
2471	  For more information on KUnit and unit tests in general please refer
2472	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2473
2474	  This is intended to help people writing architecture-specific
2475	  optimized versions. If unsure, say N.
2476
2477config RESOURCE_KUNIT_TEST
2478	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2479	depends on KUNIT
2480	default KUNIT_ALL_TESTS
2481	help
2482	  This builds the resource API unit test.
2483	  Tests the logic of API provided by resource.c and ioport.h.
2484	  For more information on KUnit and unit tests in general please refer
2485	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2486
2487	  If unsure, say N.
2488
2489config SYSCTL_KUNIT_TEST
2490	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2491	depends on KUNIT
2492	default KUNIT_ALL_TESTS
2493	help
2494	  This builds the proc sysctl unit test, which runs on boot.
2495	  Tests the API contract and implementation correctness of sysctl.
2496	  For more information on KUnit and unit tests in general please refer
2497	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2498
2499	  If unsure, say N.
2500
2501config LIST_KUNIT_TEST
2502	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2503	depends on KUNIT
2504	default KUNIT_ALL_TESTS
2505	help
2506	  This builds the linked list KUnit test suite.
2507	  It tests that the API and basic functionality of the list_head type
2508	  and associated macros.
2509
2510	  KUnit tests run during boot and output the results to the debug log
2511	  in TAP format (https://testanything.org/). Only useful for kernel devs
2512	  running the KUnit test harness, and not intended for inclusion into a
2513	  production build.
2514
2515	  For more information on KUnit and unit tests in general please refer
2516	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2517
2518	  If unsure, say N.
2519
2520config HASHTABLE_KUNIT_TEST
2521	tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2522	depends on KUNIT
2523	default KUNIT_ALL_TESTS
2524	help
2525	  This builds the hashtable KUnit test suite.
2526	  It tests the basic functionality of the API defined in
2527	  include/linux/hashtable.h. For more information on KUnit and
2528	  unit tests in general please refer to the KUnit documentation
2529	  in Documentation/dev-tools/kunit/.
2530
2531	  If unsure, say N.
2532
2533config LINEAR_RANGES_TEST
2534	tristate "KUnit test for linear_ranges"
2535	depends on KUNIT
2536	select LINEAR_RANGES
2537	help
2538	  This builds the linear_ranges unit test, which runs on boot.
2539	  Tests the linear_ranges logic correctness.
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 CMDLINE_KUNIT_TEST
2546	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2547	depends on KUNIT
2548	default KUNIT_ALL_TESTS
2549	help
2550	  This builds the cmdline API unit test.
2551	  Tests the logic of API provided by cmdline.c.
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 BITS_TEST
2558	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2559	depends on KUNIT
2560	default KUNIT_ALL_TESTS
2561	help
2562	  This builds the bits unit test.
2563	  Tests the logic of macros defined in bits.h.
2564	  For more information on KUnit and unit tests in general please refer
2565	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2566
2567	  If unsure, say N.
2568
2569config SLUB_KUNIT_TEST
2570	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2571	depends on SLUB_DEBUG && KUNIT
2572	default KUNIT_ALL_TESTS
2573	help
2574	  This builds SLUB allocator unit test.
2575	  Tests SLUB cache debugging functionality.
2576	  For more information on KUnit and unit tests in general please refer
2577	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2578
2579	  If unsure, say N.
2580
2581config RATIONAL_KUNIT_TEST
2582	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2583	depends on KUNIT && RATIONAL
2584	default KUNIT_ALL_TESTS
2585	help
2586	  This builds the rational math unit test.
2587	  For more information on KUnit and unit tests in general please refer
2588	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2589
2590	  If unsure, say N.
2591
2592config MEMCPY_KUNIT_TEST
2593	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2594	depends on KUNIT
2595	default KUNIT_ALL_TESTS
2596	help
2597	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2598	  For more information on KUnit and unit tests in general please refer
2599	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2600
2601	  If unsure, say N.
2602
2603config MEMCPY_SLOW_KUNIT_TEST
2604	bool "Include exhaustive memcpy tests"
2605	depends on MEMCPY_KUNIT_TEST
2606	default y
2607	help
2608	  Some memcpy tests are quite exhaustive in checking for overlaps
2609	  and bit ranges. These can be very slow, so they are split out
2610	  as a separate config, in case they need to be disabled.
2611
2612config IS_SIGNED_TYPE_KUNIT_TEST
2613	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2614	depends on KUNIT
2615	default KUNIT_ALL_TESTS
2616	help
2617	  Builds unit tests for the is_signed_type() macro.
2618
2619	  For more information on KUnit and unit tests in general please refer
2620	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2621
2622	  If unsure, say N.
2623
2624config OVERFLOW_KUNIT_TEST
2625	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2626	depends on KUNIT
2627	default KUNIT_ALL_TESTS
2628	help
2629	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2630	  related functions.
2631
2632	  For more information on KUnit and unit tests in general please refer
2633	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2634
2635	  If unsure, say N.
2636
2637config STACKINIT_KUNIT_TEST
2638	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2639	depends on KUNIT
2640	default KUNIT_ALL_TESTS
2641	help
2642	  Test if the kernel is zero-initializing stack variables and
2643	  padding. Coverage is controlled by compiler flags,
2644	  CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2645	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2646	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2647
2648config FORTIFY_KUNIT_TEST
2649	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2650	depends on KUNIT && FORTIFY_SOURCE
2651	default KUNIT_ALL_TESTS
2652	help
2653	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2654	  by the str*() and mem*() family of functions. For testing runtime
2655	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2656
2657config HW_BREAKPOINT_KUNIT_TEST
2658	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2659	depends on HAVE_HW_BREAKPOINT
2660	depends on KUNIT=y
2661	default KUNIT_ALL_TESTS
2662	help
2663	  Tests for hw_breakpoint constraints accounting.
2664
2665	  If unsure, say N.
2666
2667config STRSCPY_KUNIT_TEST
2668	tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2669	depends on KUNIT
2670	default KUNIT_ALL_TESTS
2671
2672config SIPHASH_KUNIT_TEST
2673	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2674	depends on KUNIT
2675	default KUNIT_ALL_TESTS
2676	help
2677	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2678	  functions on boot (or module load).
2679
2680	  This is intended to help people writing architecture-specific
2681	  optimized versions.  If unsure, say N.
2682
2683config TEST_UDELAY
2684	tristate "udelay test driver"
2685	help
2686	  This builds the "udelay_test" module that helps to make sure
2687	  that udelay() is working properly.
2688
2689	  If unsure, say N.
2690
2691config TEST_STATIC_KEYS
2692	tristate "Test static keys"
2693	depends on m
2694	help
2695	  Test the static key interfaces.
2696
2697	  If unsure, say N.
2698
2699config TEST_DYNAMIC_DEBUG
2700	tristate "Test DYNAMIC_DEBUG"
2701	depends on DYNAMIC_DEBUG
2702	help
2703	  This module registers a tracer callback to count enabled
2704	  pr_debugs in a 'do_debugging' function, then alters their
2705	  enablements, calls the function, and compares counts.
2706
2707	  If unsure, say N.
2708
2709config TEST_KMOD
2710	tristate "kmod stress tester"
2711	depends on m
2712	depends on NETDEVICES && NET_CORE && INET # for TUN
2713	depends on BLOCK
2714	depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2715	select TEST_LKM
2716	select XFS_FS
2717	select TUN
2718	select BTRFS_FS
2719	help
2720	  Test the kernel's module loading mechanism: kmod. kmod implements
2721	  support to load modules using the Linux kernel's usermode helper.
2722	  This test provides a series of tests against kmod.
2723
2724	  Although technically you can either build test_kmod as a module or
2725	  into the kernel we disallow building it into the kernel since
2726	  it stress tests request_module() and this will very likely cause
2727	  some issues by taking over precious threads available from other
2728	  module load requests, ultimately this could be fatal.
2729
2730	  To run tests run:
2731
2732	  tools/testing/selftests/kmod/kmod.sh --help
2733
2734	  If unsure, say N.
2735
2736config TEST_DEBUG_VIRTUAL
2737	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2738	depends on DEBUG_VIRTUAL
2739	help
2740	  Test the kernel's ability to detect incorrect calls to
2741	  virt_to_phys() done against the non-linear part of the
2742	  kernel's virtual address map.
2743
2744	  If unsure, say N.
2745
2746config TEST_MEMCAT_P
2747	tristate "Test memcat_p() helper function"
2748	help
2749	  Test the memcat_p() helper for correctly merging two
2750	  pointer arrays together.
2751
2752	  If unsure, say N.
2753
2754config TEST_LIVEPATCH
2755	tristate "Test livepatching"
2756	default n
2757	depends on DYNAMIC_DEBUG
2758	depends on LIVEPATCH
2759	depends on m
2760	help
2761	  Test kernel livepatching features for correctness.  The tests will
2762	  load test modules that will be livepatched in various scenarios.
2763
2764	  To run all the livepatching tests:
2765
2766	  make -C tools/testing/selftests TARGETS=livepatch run_tests
2767
2768	  Alternatively, individual tests may be invoked:
2769
2770	  tools/testing/selftests/livepatch/test-callbacks.sh
2771	  tools/testing/selftests/livepatch/test-livepatch.sh
2772	  tools/testing/selftests/livepatch/test-shadow-vars.sh
2773
2774	  If unsure, say N.
2775
2776config TEST_OBJAGG
2777	tristate "Perform selftest on object aggreration manager"
2778	default n
2779	depends on OBJAGG
2780	help
2781	  Enable this option to test object aggregation manager on boot
2782	  (or module load).
2783
2784config TEST_MEMINIT
2785	tristate "Test heap/page initialization"
2786	help
2787	  Test if the kernel is zero-initializing heap and page allocations.
2788	  This can be useful to test init_on_alloc and init_on_free features.
2789
2790	  If unsure, say N.
2791
2792config TEST_HMM
2793	tristate "Test HMM (Heterogeneous Memory Management)"
2794	depends on TRANSPARENT_HUGEPAGE
2795	depends on DEVICE_PRIVATE
2796	select HMM_MIRROR
2797	select MMU_NOTIFIER
2798	help
2799	  This is a pseudo device driver solely for testing HMM.
2800	  Say M here if you want to build the HMM test module.
2801	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2802
2803	  If unsure, say N.
2804
2805config TEST_FREE_PAGES
2806	tristate "Test freeing pages"
2807	help
2808	  Test that a memory leak does not occur due to a race between
2809	  freeing a block of pages and a speculative page reference.
2810	  Loading this module is safe if your kernel has the bug fixed.
2811	  If the bug is not fixed, it will leak gigabytes of memory and
2812	  probably OOM your system.
2813
2814config TEST_FPU
2815	tristate "Test floating point operations in kernel space"
2816	depends on X86 && !KCOV_INSTRUMENT_ALL
2817	help
2818	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2819	  which will trigger a sequence of floating point operations. This is used
2820	  for self-testing floating point control register setting in
2821	  kernel_fpu_begin().
2822
2823	  If unsure, say N.
2824
2825config TEST_CLOCKSOURCE_WATCHDOG
2826	tristate "Test clocksource watchdog in kernel space"
2827	depends on CLOCKSOURCE_WATCHDOG
2828	help
2829	  Enable this option to create a kernel module that will trigger
2830	  a test of the clocksource watchdog.  This module may be loaded
2831	  via modprobe or insmod in which case it will run upon being
2832	  loaded, or it may be built in, in which case it will run
2833	  shortly after boot.
2834
2835	  If unsure, say N.
2836
2837endif # RUNTIME_TESTING_MENU
2838
2839config ARCH_USE_MEMTEST
2840	bool
2841	help
2842	  An architecture should select this when it uses early_memtest()
2843	  during boot process.
2844
2845config MEMTEST
2846	bool "Memtest"
2847	depends on ARCH_USE_MEMTEST
2848	help
2849	  This option adds a kernel parameter 'memtest', which allows memtest
2850	  to be set and executed.
2851	        memtest=0, mean disabled; -- default
2852	        memtest=1, mean do 1 test pattern;
2853	        ...
2854	        memtest=17, mean do 17 test patterns.
2855	  If you are unsure how to answer this question, answer N.
2856
2857
2858
2859config HYPERV_TESTING
2860	bool "Microsoft Hyper-V driver testing"
2861	default n
2862	depends on HYPERV && DEBUG_FS
2863	help
2864	  Select this option to enable Hyper-V vmbus testing.
2865
2866endmenu # "Kernel Testing and Coverage"
2867
2868menu "Rust hacking"
2869
2870config RUST_DEBUG_ASSERTIONS
2871	bool "Debug assertions"
2872	depends on RUST
2873	help
2874	  Enables rustc's `-Cdebug-assertions` codegen option.
2875
2876	  This flag lets you turn `cfg(debug_assertions)` conditional
2877	  compilation on or off. This can be used to enable extra debugging
2878	  code in development but not in production. For example, it controls
2879	  the behavior of the standard library's `debug_assert!` macro.
2880
2881	  Note that this will apply to all Rust code, including `core`.
2882
2883	  If unsure, say N.
2884
2885config RUST_OVERFLOW_CHECKS
2886	bool "Overflow checks"
2887	default y
2888	depends on RUST
2889	help
2890	  Enables rustc's `-Coverflow-checks` codegen option.
2891
2892	  This flag allows you to control the behavior of runtime integer
2893	  overflow. When overflow-checks are enabled, a Rust panic will occur
2894	  on overflow.
2895
2896	  Note that this will apply to all Rust code, including `core`.
2897
2898	  If unsure, say Y.
2899
2900config RUST_BUILD_ASSERT_ALLOW
2901	bool "Allow unoptimized build-time assertions"
2902	depends on RUST
2903	help
2904	  Controls how are `build_error!` and `build_assert!` handled during build.
2905
2906	  If calls to them exist in the binary, it may indicate a violated invariant
2907	  or that the optimizer failed to verify the invariant during compilation.
2908
2909	  This should not happen, thus by default the build is aborted. However,
2910	  as an escape hatch, you can choose Y here to ignore them during build
2911	  and let the check be carried at runtime (with `panic!` being called if
2912	  the check fails).
2913
2914	  If unsure, say N.
2915
2916endmenu # "Rust"
2917
2918endmenu # Kernel hacking
2919