xref: /openbmc/linux/lib/Kconfig.debug (revision 2bad466c)
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 DEBUG_STACK_USAGE
756	bool "Stack utilization instrumentation"
757	depends on DEBUG_KERNEL && !IA64
758	help
759	  Enables the display of the minimum amount of free stack which each
760	  task has ever had available in the sysrq-T and sysrq-P debug output.
761
762	  This option will slow down process creation somewhat.
763
764config SCHED_STACK_END_CHECK
765	bool "Detect stack corruption on calls to schedule()"
766	depends on DEBUG_KERNEL
767	default n
768	help
769	  This option checks for a stack overrun on calls to schedule().
770	  If the stack end location is found to be over written always panic as
771	  the content of the corrupted region can no longer be trusted.
772	  This is to ensure no erroneous behaviour occurs which could result in
773	  data corruption or a sporadic crash at a later stage once the region
774	  is examined. The runtime overhead introduced is minimal.
775
776config ARCH_HAS_DEBUG_VM_PGTABLE
777	bool
778	help
779	  An architecture should select this when it can successfully
780	  build and run DEBUG_VM_PGTABLE.
781
782config DEBUG_VM_IRQSOFF
783	def_bool DEBUG_VM && !PREEMPT_RT
784
785config DEBUG_VM
786	bool "Debug VM"
787	depends on DEBUG_KERNEL
788	help
789	  Enable this to turn on extended checks in the virtual-memory system
790	  that may impact performance.
791
792	  If unsure, say N.
793
794config DEBUG_VM_SHOOT_LAZIES
795	bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
796	depends on DEBUG_VM
797	depends on MMU_LAZY_TLB_SHOOTDOWN
798	help
799	  Enable additional IPIs that ensure lazy tlb mm references are removed
800	  before the mm is freed.
801
802	  If unsure, say N.
803
804config DEBUG_VM_MAPLE_TREE
805	bool "Debug VM maple trees"
806	depends on DEBUG_VM
807	select DEBUG_MAPLE_TREE
808	help
809	  Enable VM maple tree debugging information and extra validations.
810
811	  If unsure, say N.
812
813config DEBUG_VM_RB
814	bool "Debug VM red-black trees"
815	depends on DEBUG_VM
816	help
817	  Enable VM red-black tree debugging information and extra validations.
818
819	  If unsure, say N.
820
821config DEBUG_VM_PGFLAGS
822	bool "Debug page-flags operations"
823	depends on DEBUG_VM
824	help
825	  Enables extra validation on page flags operations.
826
827	  If unsure, say N.
828
829config DEBUG_VM_PGTABLE
830	bool "Debug arch page table for semantics compliance"
831	depends on MMU
832	depends on ARCH_HAS_DEBUG_VM_PGTABLE
833	default y if DEBUG_VM
834	help
835	  This option provides a debug method which can be used to test
836	  architecture page table helper functions on various platforms in
837	  verifying if they comply with expected generic MM semantics. This
838	  will help architecture code in making sure that any changes or
839	  new additions of these helpers still conform to expected
840	  semantics of the generic MM. Platforms will have to opt in for
841	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
842
843	  If unsure, say N.
844
845config ARCH_HAS_DEBUG_VIRTUAL
846	bool
847
848config DEBUG_VIRTUAL
849	bool "Debug VM translations"
850	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
851	help
852	  Enable some costly sanity checks in virtual to page code. This can
853	  catch mistakes with virt_to_page() and friends.
854
855	  If unsure, say N.
856
857config DEBUG_NOMMU_REGIONS
858	bool "Debug the global anon/private NOMMU mapping region tree"
859	depends on DEBUG_KERNEL && !MMU
860	help
861	  This option causes the global tree of anonymous and private mapping
862	  regions to be regularly checked for invalid topology.
863
864config DEBUG_MEMORY_INIT
865	bool "Debug memory initialisation" if EXPERT
866	default !EXPERT
867	help
868	  Enable this for additional checks during memory initialisation.
869	  The sanity checks verify aspects of the VM such as the memory model
870	  and other information provided by the architecture. Verbose
871	  information will be printed at KERN_DEBUG loglevel depending
872	  on the mminit_loglevel= command-line option.
873
874	  If unsure, say Y
875
876config MEMORY_NOTIFIER_ERROR_INJECT
877	tristate "Memory hotplug notifier error injection module"
878	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
879	help
880	  This option provides the ability to inject artificial errors to
881	  memory hotplug notifier chain callbacks.  It is controlled through
882	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
883
884	  If the notifier call chain should be failed with some events
885	  notified, write the error code to "actions/<notifier event>/error".
886
887	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
888
889	  # cd /sys/kernel/debug/notifier-error-inject/memory
890	  # echo -12 > actions/MEM_GOING_OFFLINE/error
891	  # echo offline > /sys/devices/system/memory/memoryXXX/state
892	  bash: echo: write error: Cannot allocate memory
893
894	  To compile this code as a module, choose M here: the module will
895	  be called memory-notifier-error-inject.
896
897	  If unsure, say N.
898
899config DEBUG_PER_CPU_MAPS
900	bool "Debug access to per_cpu maps"
901	depends on DEBUG_KERNEL
902	depends on SMP
903	help
904	  Say Y to verify that the per_cpu map being accessed has
905	  been set up. This adds a fair amount of code to kernel memory
906	  and decreases performance.
907
908	  Say N if unsure.
909
910config DEBUG_KMAP_LOCAL
911	bool "Debug kmap_local temporary mappings"
912	depends on DEBUG_KERNEL && KMAP_LOCAL
913	help
914	  This option enables additional error checking for the kmap_local
915	  infrastructure.  Disable for production use.
916
917config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
918	bool
919
920config DEBUG_KMAP_LOCAL_FORCE_MAP
921	bool "Enforce kmap_local temporary mappings"
922	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
923	select KMAP_LOCAL
924	select DEBUG_KMAP_LOCAL
925	help
926	  This option enforces temporary mappings through the kmap_local
927	  mechanism for non-highmem pages and on non-highmem systems.
928	  Disable this for production systems!
929
930config DEBUG_HIGHMEM
931	bool "Highmem debugging"
932	depends on DEBUG_KERNEL && HIGHMEM
933	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
934	select DEBUG_KMAP_LOCAL
935	help
936	  This option enables additional error checking for high memory
937	  systems.  Disable for production systems.
938
939config HAVE_DEBUG_STACKOVERFLOW
940	bool
941
942config DEBUG_STACKOVERFLOW
943	bool "Check for stack overflows"
944	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
945	help
946	  Say Y here if you want to check for overflows of kernel, IRQ
947	  and exception stacks (if your architecture uses them). This
948	  option will show detailed messages if free stack space drops
949	  below a certain limit.
950
951	  These kinds of bugs usually occur when call-chains in the
952	  kernel get too deep, especially when interrupts are
953	  involved.
954
955	  Use this in cases where you see apparently random memory
956	  corruption, especially if it appears in 'struct thread_info'
957
958	  If in doubt, say "N".
959
960source "lib/Kconfig.kasan"
961source "lib/Kconfig.kfence"
962source "lib/Kconfig.kmsan"
963
964endmenu # "Memory Debugging"
965
966config DEBUG_SHIRQ
967	bool "Debug shared IRQ handlers"
968	depends on DEBUG_KERNEL
969	help
970	  Enable this to generate a spurious interrupt just before a shared
971	  interrupt handler is deregistered (generating one when registering
972	  is currently disabled). Drivers need to handle this correctly. Some
973	  don't and need to be caught.
974
975menu "Debug Oops, Lockups and Hangs"
976
977config PANIC_ON_OOPS
978	bool "Panic on Oops"
979	help
980	  Say Y here to enable the kernel to panic when it oopses. This
981	  has the same effect as setting oops=panic on the kernel command
982	  line.
983
984	  This feature is useful to ensure that the kernel does not do
985	  anything erroneous after an oops which could result in data
986	  corruption or other issues.
987
988	  Say N if unsure.
989
990config PANIC_ON_OOPS_VALUE
991	int
992	range 0 1
993	default 0 if !PANIC_ON_OOPS
994	default 1 if PANIC_ON_OOPS
995
996config PANIC_TIMEOUT
997	int "panic timeout"
998	default 0
999	help
1000	  Set the timeout value (in seconds) until a reboot occurs when
1001	  the kernel panics. If n = 0, then we wait forever. A timeout
1002	  value n > 0 will wait n seconds before rebooting, while a timeout
1003	  value n < 0 will reboot immediately.
1004
1005config LOCKUP_DETECTOR
1006	bool
1007
1008config SOFTLOCKUP_DETECTOR
1009	bool "Detect Soft Lockups"
1010	depends on DEBUG_KERNEL && !S390
1011	select LOCKUP_DETECTOR
1012	help
1013	  Say Y here to enable the kernel to act as a watchdog to detect
1014	  soft lockups.
1015
1016	  Softlockups are bugs that cause the kernel to loop in kernel
1017	  mode for more than 20 seconds, without giving other tasks a
1018	  chance to run.  The current stack trace is displayed upon
1019	  detection and the system will stay locked up.
1020
1021config BOOTPARAM_SOFTLOCKUP_PANIC
1022	bool "Panic (Reboot) On Soft Lockups"
1023	depends on SOFTLOCKUP_DETECTOR
1024	help
1025	  Say Y here to enable the kernel to panic on "soft lockups",
1026	  which are bugs that cause the kernel to loop in kernel
1027	  mode for more than 20 seconds (configurable using the watchdog_thresh
1028	  sysctl), without giving other tasks a chance to run.
1029
1030	  The panic can be used in combination with panic_timeout,
1031	  to cause the system to reboot automatically after a
1032	  lockup has been detected. This feature is useful for
1033	  high-availability systems that have uptime guarantees and
1034	  where a lockup must be resolved ASAP.
1035
1036	  Say N if unsure.
1037
1038config HARDLOCKUP_DETECTOR_PERF
1039	bool
1040	select SOFTLOCKUP_DETECTOR
1041
1042#
1043# Enables a timestamp based low pass filter to compensate for perf based
1044# hard lockup detection which runs too fast due to turbo modes.
1045#
1046config HARDLOCKUP_CHECK_TIMESTAMP
1047	bool
1048
1049#
1050# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1051# lockup detector rather than the perf based detector.
1052#
1053config HARDLOCKUP_DETECTOR
1054	bool "Detect Hard Lockups"
1055	depends on DEBUG_KERNEL && !S390
1056	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1057	select LOCKUP_DETECTOR
1058	select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1059	help
1060	  Say Y here to enable the kernel to act as a watchdog to detect
1061	  hard lockups.
1062
1063	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1064	  for more than 10 seconds, without letting other interrupts have a
1065	  chance to run.  The current stack trace is displayed upon detection
1066	  and the system will stay locked up.
1067
1068config BOOTPARAM_HARDLOCKUP_PANIC
1069	bool "Panic (Reboot) On Hard Lockups"
1070	depends on HARDLOCKUP_DETECTOR
1071	help
1072	  Say Y here to enable the kernel to panic on "hard lockups",
1073	  which are bugs that cause the kernel to loop in kernel
1074	  mode with interrupts disabled for more than 10 seconds (configurable
1075	  using the watchdog_thresh sysctl).
1076
1077	  Say N if unsure.
1078
1079config DETECT_HUNG_TASK
1080	bool "Detect Hung Tasks"
1081	depends on DEBUG_KERNEL
1082	default SOFTLOCKUP_DETECTOR
1083	help
1084	  Say Y here to enable the kernel to detect "hung tasks",
1085	  which are bugs that cause the task to be stuck in
1086	  uninterruptible "D" state indefinitely.
1087
1088	  When a hung task is detected, the kernel will print the
1089	  current stack trace (which you should report), but the
1090	  task will stay in uninterruptible state. If lockdep is
1091	  enabled then all held locks will also be reported. This
1092	  feature has negligible overhead.
1093
1094config DEFAULT_HUNG_TASK_TIMEOUT
1095	int "Default timeout for hung task detection (in seconds)"
1096	depends on DETECT_HUNG_TASK
1097	default 120
1098	help
1099	  This option controls the default timeout (in seconds) used
1100	  to determine when a task has become non-responsive and should
1101	  be considered hung.
1102
1103	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1104	  sysctl or by writing a value to
1105	  /proc/sys/kernel/hung_task_timeout_secs.
1106
1107	  A timeout of 0 disables the check.  The default is two minutes.
1108	  Keeping the default should be fine in most cases.
1109
1110config BOOTPARAM_HUNG_TASK_PANIC
1111	bool "Panic (Reboot) On Hung Tasks"
1112	depends on DETECT_HUNG_TASK
1113	help
1114	  Say Y here to enable the kernel to panic on "hung tasks",
1115	  which are bugs that cause the kernel to leave a task stuck
1116	  in uninterruptible "D" state.
1117
1118	  The panic can be used in combination with panic_timeout,
1119	  to cause the system to reboot automatically after a
1120	  hung task has been detected. This feature is useful for
1121	  high-availability systems that have uptime guarantees and
1122	  where a hung tasks must be resolved ASAP.
1123
1124	  Say N if unsure.
1125
1126config WQ_WATCHDOG
1127	bool "Detect Workqueue Stalls"
1128	depends on DEBUG_KERNEL
1129	help
1130	  Say Y here to enable stall detection on workqueues.  If a
1131	  worker pool doesn't make forward progress on a pending work
1132	  item for over a given amount of time, 30s by default, a
1133	  warning message is printed along with dump of workqueue
1134	  state.  This can be configured through kernel parameter
1135	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1136
1137config TEST_LOCKUP
1138	tristate "Test module to generate lockups"
1139	depends on m
1140	help
1141	  This builds the "test_lockup" module that helps to make sure
1142	  that watchdogs and lockup detectors are working properly.
1143
1144	  Depending on module parameters it could emulate soft or hard
1145	  lockup, "hung task", or locking arbitrary lock for a long time.
1146	  Also it could generate series of lockups with cooling-down periods.
1147
1148	  If unsure, say N.
1149
1150endmenu # "Debug lockups and hangs"
1151
1152menu "Scheduler Debugging"
1153
1154config SCHED_DEBUG
1155	bool "Collect scheduler debugging info"
1156	depends on DEBUG_KERNEL && DEBUG_FS
1157	default y
1158	help
1159	  If you say Y here, the /sys/kernel/debug/sched file will be provided
1160	  that can help debug the scheduler. The runtime overhead of this
1161	  option is minimal.
1162
1163config SCHED_INFO
1164	bool
1165	default n
1166
1167config SCHEDSTATS
1168	bool "Collect scheduler statistics"
1169	depends on DEBUG_KERNEL && PROC_FS
1170	select SCHED_INFO
1171	help
1172	  If you say Y here, additional code will be inserted into the
1173	  scheduler and related routines to collect statistics about
1174	  scheduler behavior and provide them in /proc/schedstat.  These
1175	  stats may be useful for both tuning and debugging the scheduler
1176	  If you aren't debugging the scheduler or trying to tune a specific
1177	  application, you can say N to avoid the very slight overhead
1178	  this adds.
1179
1180endmenu
1181
1182config DEBUG_TIMEKEEPING
1183	bool "Enable extra timekeeping sanity checking"
1184	help
1185	  This option will enable additional timekeeping sanity checks
1186	  which may be helpful when diagnosing issues where timekeeping
1187	  problems are suspected.
1188
1189	  This may include checks in the timekeeping hotpaths, so this
1190	  option may have a (very small) performance impact to some
1191	  workloads.
1192
1193	  If unsure, say N.
1194
1195config DEBUG_PREEMPT
1196	bool "Debug preemptible kernel"
1197	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1198	help
1199	  If you say Y here then the kernel will use a debug variant of the
1200	  commonly used smp_processor_id() function and will print warnings
1201	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1202	  will detect preemption count underflows.
1203
1204	  This option has potential to introduce high runtime overhead,
1205	  depending on workload as it triggers debugging routines for each
1206	  this_cpu operation. It should only be used for debugging purposes.
1207
1208menu "Lock Debugging (spinlocks, mutexes, etc...)"
1209
1210config LOCK_DEBUGGING_SUPPORT
1211	bool
1212	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1213	default y
1214
1215config PROVE_LOCKING
1216	bool "Lock debugging: prove locking correctness"
1217	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1218	select LOCKDEP
1219	select DEBUG_SPINLOCK
1220	select DEBUG_MUTEXES if !PREEMPT_RT
1221	select DEBUG_RT_MUTEXES if RT_MUTEXES
1222	select DEBUG_RWSEMS
1223	select DEBUG_WW_MUTEX_SLOWPATH
1224	select DEBUG_LOCK_ALLOC
1225	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1226	select TRACE_IRQFLAGS
1227	default n
1228	help
1229	 This feature enables the kernel to prove that all locking
1230	 that occurs in the kernel runtime is mathematically
1231	 correct: that under no circumstance could an arbitrary (and
1232	 not yet triggered) combination of observed locking
1233	 sequences (on an arbitrary number of CPUs, running an
1234	 arbitrary number of tasks and interrupt contexts) cause a
1235	 deadlock.
1236
1237	 In short, this feature enables the kernel to report locking
1238	 related deadlocks before they actually occur.
1239
1240	 The proof does not depend on how hard and complex a
1241	 deadlock scenario would be to trigger: how many
1242	 participant CPUs, tasks and irq-contexts would be needed
1243	 for it to trigger. The proof also does not depend on
1244	 timing: if a race and a resulting deadlock is possible
1245	 theoretically (no matter how unlikely the race scenario
1246	 is), it will be proven so and will immediately be
1247	 reported by the kernel (once the event is observed that
1248	 makes the deadlock theoretically possible).
1249
1250	 If a deadlock is impossible (i.e. the locking rules, as
1251	 observed by the kernel, are mathematically correct), the
1252	 kernel reports nothing.
1253
1254	 NOTE: this feature can also be enabled for rwlocks, mutexes
1255	 and rwsems - in which case all dependencies between these
1256	 different locking variants are observed and mapped too, and
1257	 the proof of observed correctness is also maintained for an
1258	 arbitrary combination of these separate locking variants.
1259
1260	 For more details, see Documentation/locking/lockdep-design.rst.
1261
1262config PROVE_RAW_LOCK_NESTING
1263	bool "Enable raw_spinlock - spinlock nesting checks"
1264	depends on PROVE_LOCKING
1265	default n
1266	help
1267	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1268	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1269	 not violated.
1270
1271	 NOTE: There are known nesting problems. So if you enable this
1272	 option expect lockdep splats until these problems have been fully
1273	 addressed which is work in progress. This config switch allows to
1274	 identify and analyze these problems. It will be removed and the
1275	 check permanently enabled once the main issues have been fixed.
1276
1277	 If unsure, select N.
1278
1279config LOCK_STAT
1280	bool "Lock usage statistics"
1281	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1282	select LOCKDEP
1283	select DEBUG_SPINLOCK
1284	select DEBUG_MUTEXES if !PREEMPT_RT
1285	select DEBUG_RT_MUTEXES if RT_MUTEXES
1286	select DEBUG_LOCK_ALLOC
1287	default n
1288	help
1289	 This feature enables tracking lock contention points
1290
1291	 For more details, see Documentation/locking/lockstat.rst
1292
1293	 This also enables lock events required by "perf lock",
1294	 subcommand of perf.
1295	 If you want to use "perf lock", you also need to turn on
1296	 CONFIG_EVENT_TRACING.
1297
1298	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1299	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1300
1301config DEBUG_RT_MUTEXES
1302	bool "RT Mutex debugging, deadlock detection"
1303	depends on DEBUG_KERNEL && RT_MUTEXES
1304	help
1305	 This allows rt mutex semantics violations and rt mutex related
1306	 deadlocks (lockups) to be detected and reported automatically.
1307
1308config DEBUG_SPINLOCK
1309	bool "Spinlock and rw-lock debugging: basic checks"
1310	depends on DEBUG_KERNEL
1311	select UNINLINE_SPIN_UNLOCK
1312	help
1313	  Say Y here and build SMP to catch missing spinlock initialization
1314	  and certain other kinds of spinlock errors commonly made.  This is
1315	  best used in conjunction with the NMI watchdog so that spinlock
1316	  deadlocks are also debuggable.
1317
1318config DEBUG_MUTEXES
1319	bool "Mutex debugging: basic checks"
1320	depends on DEBUG_KERNEL && !PREEMPT_RT
1321	help
1322	 This feature allows mutex semantics violations to be detected and
1323	 reported.
1324
1325config DEBUG_WW_MUTEX_SLOWPATH
1326	bool "Wait/wound mutex debugging: Slowpath testing"
1327	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1328	select DEBUG_LOCK_ALLOC
1329	select DEBUG_SPINLOCK
1330	select DEBUG_MUTEXES if !PREEMPT_RT
1331	select DEBUG_RT_MUTEXES if PREEMPT_RT
1332	help
1333	 This feature enables slowpath testing for w/w mutex users by
1334	 injecting additional -EDEADLK wound/backoff cases. Together with
1335	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1336	 will test all possible w/w mutex interface abuse with the
1337	 exception of simply not acquiring all the required locks.
1338	 Note that this feature can introduce significant overhead, so
1339	 it really should not be enabled in a production or distro kernel,
1340	 even a debug kernel.  If you are a driver writer, enable it.  If
1341	 you are a distro, do not.
1342
1343config DEBUG_RWSEMS
1344	bool "RW Semaphore debugging: basic checks"
1345	depends on DEBUG_KERNEL
1346	help
1347	  This debugging feature allows mismatched rw semaphore locks
1348	  and unlocks to be detected and reported.
1349
1350config DEBUG_LOCK_ALLOC
1351	bool "Lock debugging: detect incorrect freeing of live locks"
1352	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1353	select DEBUG_SPINLOCK
1354	select DEBUG_MUTEXES if !PREEMPT_RT
1355	select DEBUG_RT_MUTEXES if RT_MUTEXES
1356	select LOCKDEP
1357	help
1358	 This feature will check whether any held lock (spinlock, rwlock,
1359	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1360	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1361	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1362	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1363	 held during task exit.
1364
1365config LOCKDEP
1366	bool
1367	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1368	select STACKTRACE
1369	select KALLSYMS
1370	select KALLSYMS_ALL
1371
1372config LOCKDEP_SMALL
1373	bool
1374
1375config LOCKDEP_BITS
1376	int "Bitsize for MAX_LOCKDEP_ENTRIES"
1377	depends on LOCKDEP && !LOCKDEP_SMALL
1378	range 10 30
1379	default 15
1380	help
1381	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1382
1383config LOCKDEP_CHAINS_BITS
1384	int "Bitsize for MAX_LOCKDEP_CHAINS"
1385	depends on LOCKDEP && !LOCKDEP_SMALL
1386	range 10 30
1387	default 16
1388	help
1389	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1390
1391config LOCKDEP_STACK_TRACE_BITS
1392	int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1393	depends on LOCKDEP && !LOCKDEP_SMALL
1394	range 10 30
1395	default 19
1396	help
1397	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1398
1399config LOCKDEP_STACK_TRACE_HASH_BITS
1400	int "Bitsize for STACK_TRACE_HASH_SIZE"
1401	depends on LOCKDEP && !LOCKDEP_SMALL
1402	range 10 30
1403	default 14
1404	help
1405	  Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1406
1407config LOCKDEP_CIRCULAR_QUEUE_BITS
1408	int "Bitsize for elements in circular_queue struct"
1409	depends on LOCKDEP
1410	range 10 30
1411	default 12
1412	help
1413	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1414
1415config DEBUG_LOCKDEP
1416	bool "Lock dependency engine debugging"
1417	depends on DEBUG_KERNEL && LOCKDEP
1418	select DEBUG_IRQFLAGS
1419	help
1420	  If you say Y here, the lock dependency engine will do
1421	  additional runtime checks to debug itself, at the price
1422	  of more runtime overhead.
1423
1424config DEBUG_ATOMIC_SLEEP
1425	bool "Sleep inside atomic section checking"
1426	select PREEMPT_COUNT
1427	depends on DEBUG_KERNEL
1428	depends on !ARCH_NO_PREEMPT
1429	help
1430	  If you say Y here, various routines which may sleep will become very
1431	  noisy if they are called inside atomic sections: when a spinlock is
1432	  held, inside an rcu read side critical section, inside preempt disabled
1433	  sections, inside an interrupt, etc...
1434
1435config DEBUG_LOCKING_API_SELFTESTS
1436	bool "Locking API boot-time self-tests"
1437	depends on DEBUG_KERNEL
1438	help
1439	  Say Y here if you want the kernel to run a short self-test during
1440	  bootup. The self-test checks whether common types of locking bugs
1441	  are detected by debugging mechanisms or not. (if you disable
1442	  lock debugging then those bugs won't be detected of course.)
1443	  The following locking APIs are covered: spinlocks, rwlocks,
1444	  mutexes and rwsems.
1445
1446config LOCK_TORTURE_TEST
1447	tristate "torture tests for locking"
1448	depends on DEBUG_KERNEL
1449	select TORTURE_TEST
1450	help
1451	  This option provides a kernel module that runs torture tests
1452	  on kernel locking primitives.  The kernel module may be built
1453	  after the fact on the running kernel to be tested, if desired.
1454
1455	  Say Y here if you want kernel locking-primitive torture tests
1456	  to be built into the kernel.
1457	  Say M if you want these torture tests to build as a module.
1458	  Say N if you are unsure.
1459
1460config WW_MUTEX_SELFTEST
1461	tristate "Wait/wound mutex selftests"
1462	help
1463	  This option provides a kernel module that runs tests on the
1464	  on the struct ww_mutex locking API.
1465
1466	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1467	  with this test harness.
1468
1469	  Say M if you want these self tests to build as a module.
1470	  Say N if you are unsure.
1471
1472config SCF_TORTURE_TEST
1473	tristate "torture tests for smp_call_function*()"
1474	depends on DEBUG_KERNEL
1475	select TORTURE_TEST
1476	help
1477	  This option provides a kernel module that runs torture tests
1478	  on the smp_call_function() family of primitives.  The kernel
1479	  module may be built after the fact on the running kernel to
1480	  be tested, if desired.
1481
1482config CSD_LOCK_WAIT_DEBUG
1483	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1484	depends on DEBUG_KERNEL
1485	depends on 64BIT
1486	default n
1487	help
1488	  This option enables debug prints when CPUs are slow to respond
1489	  to the smp_call_function*() IPI wrappers.  These debug prints
1490	  include the IPI handler function currently executing (if any)
1491	  and relevant stack traces.
1492
1493endmenu # lock debugging
1494
1495config TRACE_IRQFLAGS
1496	depends on TRACE_IRQFLAGS_SUPPORT
1497	bool
1498	help
1499	  Enables hooks to interrupt enabling and disabling for
1500	  either tracing or lock debugging.
1501
1502config TRACE_IRQFLAGS_NMI
1503	def_bool y
1504	depends on TRACE_IRQFLAGS
1505	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1506
1507config NMI_CHECK_CPU
1508	bool "Debugging for CPUs failing to respond to backtrace requests"
1509	depends on DEBUG_KERNEL
1510	depends on X86
1511	default n
1512	help
1513	  Enables debug prints when a CPU fails to respond to a given
1514	  backtrace NMI.  These prints provide some reasons why a CPU
1515	  might legitimately be failing to respond, for example, if it
1516	  is offline of if ignore_nmis is set.
1517
1518config DEBUG_IRQFLAGS
1519	bool "Debug IRQ flag manipulation"
1520	help
1521	  Enables checks for potentially unsafe enabling or disabling of
1522	  interrupts, such as calling raw_local_irq_restore() when interrupts
1523	  are enabled.
1524
1525config STACKTRACE
1526	bool "Stack backtrace support"
1527	depends on STACKTRACE_SUPPORT
1528	help
1529	  This option causes the kernel to create a /proc/pid/stack for
1530	  every process, showing its current stack trace.
1531	  It is also used by various kernel debugging features that require
1532	  stack trace generation.
1533
1534config WARN_ALL_UNSEEDED_RANDOM
1535	bool "Warn for all uses of unseeded randomness"
1536	default n
1537	help
1538	  Some parts of the kernel contain bugs relating to their use of
1539	  cryptographically secure random numbers before it's actually possible
1540	  to generate those numbers securely. This setting ensures that these
1541	  flaws don't go unnoticed, by enabling a message, should this ever
1542	  occur. This will allow people with obscure setups to know when things
1543	  are going wrong, so that they might contact developers about fixing
1544	  it.
1545
1546	  Unfortunately, on some models of some architectures getting
1547	  a fully seeded CRNG is extremely difficult, and so this can
1548	  result in dmesg getting spammed for a surprisingly long
1549	  time.  This is really bad from a security perspective, and
1550	  so architecture maintainers really need to do what they can
1551	  to get the CRNG seeded sooner after the system is booted.
1552	  However, since users cannot do anything actionable to
1553	  address this, by default this option is disabled.
1554
1555	  Say Y here if you want to receive warnings for all uses of
1556	  unseeded randomness.  This will be of use primarily for
1557	  those developers interested in improving the security of
1558	  Linux kernels running on their architecture (or
1559	  subarchitecture).
1560
1561config DEBUG_KOBJECT
1562	bool "kobject debugging"
1563	depends on DEBUG_KERNEL
1564	help
1565	  If you say Y here, some extra kobject debugging messages will be sent
1566	  to the syslog.
1567
1568config DEBUG_KOBJECT_RELEASE
1569	bool "kobject release debugging"
1570	depends on DEBUG_OBJECTS_TIMERS
1571	help
1572	  kobjects are reference counted objects.  This means that their
1573	  last reference count put is not predictable, and the kobject can
1574	  live on past the point at which a driver decides to drop its
1575	  initial reference to the kobject gained on allocation.  An
1576	  example of this would be a struct device which has just been
1577	  unregistered.
1578
1579	  However, some buggy drivers assume that after such an operation,
1580	  the memory backing the kobject can be immediately freed.  This
1581	  goes completely against the principles of a refcounted object.
1582
1583	  If you say Y here, the kernel will delay the release of kobjects
1584	  on the last reference count to improve the visibility of this
1585	  kind of kobject release bug.
1586
1587config HAVE_DEBUG_BUGVERBOSE
1588	bool
1589
1590menu "Debug kernel data structures"
1591
1592config DEBUG_LIST
1593	bool "Debug linked list manipulation"
1594	depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1595	help
1596	  Enable this to turn on extended checks in the linked-list
1597	  walking routines.
1598
1599	  If unsure, say N.
1600
1601config DEBUG_PLIST
1602	bool "Debug priority linked list manipulation"
1603	depends on DEBUG_KERNEL
1604	help
1605	  Enable this to turn on extended checks in the priority-ordered
1606	  linked-list (plist) walking routines.  This checks the entire
1607	  list multiple times during each manipulation.
1608
1609	  If unsure, say N.
1610
1611config DEBUG_SG
1612	bool "Debug SG table operations"
1613	depends on DEBUG_KERNEL
1614	help
1615	  Enable this to turn on checks on scatter-gather tables. This can
1616	  help find problems with drivers that do not properly initialize
1617	  their sg tables.
1618
1619	  If unsure, say N.
1620
1621config DEBUG_NOTIFIERS
1622	bool "Debug notifier call chains"
1623	depends on DEBUG_KERNEL
1624	help
1625	  Enable this to turn on sanity checking for notifier call chains.
1626	  This is most useful for kernel developers to make sure that
1627	  modules properly unregister themselves from notifier chains.
1628	  This is a relatively cheap check but if you care about maximum
1629	  performance, say N.
1630
1631config BUG_ON_DATA_CORRUPTION
1632	bool "Trigger a BUG when data corruption is detected"
1633	select DEBUG_LIST
1634	help
1635	  Select this option if the kernel should BUG when it encounters
1636	  data corruption in kernel memory structures when they get checked
1637	  for validity.
1638
1639	  If unsure, say N.
1640
1641config DEBUG_MAPLE_TREE
1642	bool "Debug maple trees"
1643	depends on DEBUG_KERNEL
1644	help
1645	  Enable maple tree debugging information and extra validations.
1646
1647	  If unsure, say N.
1648
1649endmenu
1650
1651config DEBUG_CREDENTIALS
1652	bool "Debug credential management"
1653	depends on DEBUG_KERNEL
1654	help
1655	  Enable this to turn on some debug checking for credential
1656	  management.  The additional code keeps track of the number of
1657	  pointers from task_structs to any given cred struct, and checks to
1658	  see that this number never exceeds the usage count of the cred
1659	  struct.
1660
1661	  Furthermore, if SELinux is enabled, this also checks that the
1662	  security pointer in the cred struct is never seen to be invalid.
1663
1664	  If unsure, say N.
1665
1666source "kernel/rcu/Kconfig.debug"
1667
1668config DEBUG_WQ_FORCE_RR_CPU
1669	bool "Force round-robin CPU selection for unbound work items"
1670	depends on DEBUG_KERNEL
1671	default n
1672	help
1673	  Workqueue used to implicitly guarantee that work items queued
1674	  without explicit CPU specified are put on the local CPU.  This
1675	  guarantee is no longer true and while local CPU is still
1676	  preferred work items may be put on foreign CPUs.  Kernel
1677	  parameter "workqueue.debug_force_rr_cpu" is added to force
1678	  round-robin CPU selection to flush out usages which depend on the
1679	  now broken guarantee.  This config option enables the debug
1680	  feature by default.  When enabled, memory and cache locality will
1681	  be impacted.
1682
1683config CPU_HOTPLUG_STATE_CONTROL
1684	bool "Enable CPU hotplug state control"
1685	depends on DEBUG_KERNEL
1686	depends on HOTPLUG_CPU
1687	default n
1688	help
1689	  Allows to write steps between "offline" and "online" to the CPUs
1690	  sysfs target file so states can be stepped granular. This is a debug
1691	  option for now as the hotplug machinery cannot be stopped and
1692	  restarted at arbitrary points yet.
1693
1694	  Say N if your are unsure.
1695
1696config LATENCYTOP
1697	bool "Latency measuring infrastructure"
1698	depends on DEBUG_KERNEL
1699	depends on STACKTRACE_SUPPORT
1700	depends on PROC_FS
1701	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1702	select KALLSYMS
1703	select KALLSYMS_ALL
1704	select STACKTRACE
1705	select SCHEDSTATS
1706	help
1707	  Enable this option if you want to use the LatencyTOP tool
1708	  to find out which userspace is blocking on what kernel operations.
1709
1710config DEBUG_CGROUP_REF
1711	bool "Disable inlining of cgroup css reference count functions"
1712	depends on DEBUG_KERNEL
1713	depends on CGROUPS
1714	depends on KPROBES
1715	default n
1716	help
1717	  Force cgroup css reference count functions to not be inlined so
1718	  that they can be kprobed for debugging.
1719
1720source "kernel/trace/Kconfig"
1721
1722config PROVIDE_OHCI1394_DMA_INIT
1723	bool "Remote debugging over FireWire early on boot"
1724	depends on PCI && X86
1725	help
1726	  If you want to debug problems which hang or crash the kernel early
1727	  on boot and the crashing machine has a FireWire port, you can use
1728	  this feature to remotely access the memory of the crashed machine
1729	  over FireWire. This employs remote DMA as part of the OHCI1394
1730	  specification which is now the standard for FireWire controllers.
1731
1732	  With remote DMA, you can monitor the printk buffer remotely using
1733	  firescope and access all memory below 4GB using fireproxy from gdb.
1734	  Even controlling a kernel debugger is possible using remote DMA.
1735
1736	  Usage:
1737
1738	  If ohci1394_dma=early is used as boot parameter, it will initialize
1739	  all OHCI1394 controllers which are found in the PCI config space.
1740
1741	  As all changes to the FireWire bus such as enabling and disabling
1742	  devices cause a bus reset and thereby disable remote DMA for all
1743	  devices, be sure to have the cable plugged and FireWire enabled on
1744	  the debugging host before booting the debug target for debugging.
1745
1746	  This code (~1k) is freed after boot. By then, the firewire stack
1747	  in charge of the OHCI-1394 controllers should be used instead.
1748
1749	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1750
1751source "samples/Kconfig"
1752
1753config ARCH_HAS_DEVMEM_IS_ALLOWED
1754	bool
1755
1756config STRICT_DEVMEM
1757	bool "Filter access to /dev/mem"
1758	depends on MMU && DEVMEM
1759	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1760	default y if PPC || X86 || ARM64
1761	help
1762	  If this option is disabled, you allow userspace (root) access to all
1763	  of memory, including kernel and userspace memory. Accidental
1764	  access to this is obviously disastrous, but specific access can
1765	  be used by people debugging the kernel. Note that with PAT support
1766	  enabled, even in this case there are restrictions on /dev/mem
1767	  use due to the cache aliasing requirements.
1768
1769	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1770	  file only allows userspace access to PCI space and the BIOS code and
1771	  data regions.  This is sufficient for dosemu and X and all common
1772	  users of /dev/mem.
1773
1774	  If in doubt, say Y.
1775
1776config IO_STRICT_DEVMEM
1777	bool "Filter I/O access to /dev/mem"
1778	depends on STRICT_DEVMEM
1779	help
1780	  If this option is disabled, you allow userspace (root) access to all
1781	  io-memory regardless of whether a driver is actively using that
1782	  range.  Accidental access to this is obviously disastrous, but
1783	  specific access can be used by people debugging kernel drivers.
1784
1785	  If this option is switched on, the /dev/mem file only allows
1786	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1787	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1788	  if the driver using a given range cannot be disabled.
1789
1790	  If in doubt, say Y.
1791
1792menu "$(SRCARCH) Debugging"
1793
1794source "arch/$(SRCARCH)/Kconfig.debug"
1795
1796endmenu
1797
1798menu "Kernel Testing and Coverage"
1799
1800source "lib/kunit/Kconfig"
1801
1802config NOTIFIER_ERROR_INJECTION
1803	tristate "Notifier error injection"
1804	depends on DEBUG_KERNEL
1805	select DEBUG_FS
1806	help
1807	  This option provides the ability to inject artificial errors to
1808	  specified notifier chain callbacks. It is useful to test the error
1809	  handling of notifier call chain failures.
1810
1811	  Say N if unsure.
1812
1813config PM_NOTIFIER_ERROR_INJECT
1814	tristate "PM notifier error injection module"
1815	depends on PM && NOTIFIER_ERROR_INJECTION
1816	default m if PM_DEBUG
1817	help
1818	  This option provides the ability to inject artificial errors to
1819	  PM notifier chain callbacks.  It is controlled through debugfs
1820	  interface /sys/kernel/debug/notifier-error-inject/pm
1821
1822	  If the notifier call chain should be failed with some events
1823	  notified, write the error code to "actions/<notifier event>/error".
1824
1825	  Example: Inject PM suspend error (-12 = -ENOMEM)
1826
1827	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1828	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1829	  # echo mem > /sys/power/state
1830	  bash: echo: write error: Cannot allocate memory
1831
1832	  To compile this code as a module, choose M here: the module will
1833	  be called pm-notifier-error-inject.
1834
1835	  If unsure, say N.
1836
1837config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1838	tristate "OF reconfig notifier error injection module"
1839	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1840	help
1841	  This option provides the ability to inject artificial errors to
1842	  OF reconfig notifier chain callbacks.  It is controlled
1843	  through debugfs interface under
1844	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1845
1846	  If the notifier call chain should be failed with some events
1847	  notified, write the error code to "actions/<notifier event>/error".
1848
1849	  To compile this code as a module, choose M here: the module will
1850	  be called of-reconfig-notifier-error-inject.
1851
1852	  If unsure, say N.
1853
1854config NETDEV_NOTIFIER_ERROR_INJECT
1855	tristate "Netdev notifier error injection module"
1856	depends on NET && NOTIFIER_ERROR_INJECTION
1857	help
1858	  This option provides the ability to inject artificial errors to
1859	  netdevice notifier chain callbacks.  It is controlled through debugfs
1860	  interface /sys/kernel/debug/notifier-error-inject/netdev
1861
1862	  If the notifier call chain should be failed with some events
1863	  notified, write the error code to "actions/<notifier event>/error".
1864
1865	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
1866
1867	  # cd /sys/kernel/debug/notifier-error-inject/netdev
1868	  # echo -22 > actions/NETDEV_CHANGEMTU/error
1869	  # ip link set eth0 mtu 1024
1870	  RTNETLINK answers: Invalid argument
1871
1872	  To compile this code as a module, choose M here: the module will
1873	  be called netdev-notifier-error-inject.
1874
1875	  If unsure, say N.
1876
1877config FUNCTION_ERROR_INJECTION
1878	bool "Fault-injections of functions"
1879	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1880	help
1881	  Add fault injections into various functions that are annotated with
1882	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1883	  value of these functions. This is useful to test error paths of code.
1884
1885	  If unsure, say N
1886
1887config FAULT_INJECTION
1888	bool "Fault-injection framework"
1889	depends on DEBUG_KERNEL
1890	help
1891	  Provide fault-injection framework.
1892	  For more details, see Documentation/fault-injection/.
1893
1894config FAILSLAB
1895	bool "Fault-injection capability for kmalloc"
1896	depends on FAULT_INJECTION
1897	depends on SLAB || SLUB
1898	help
1899	  Provide fault-injection capability for kmalloc.
1900
1901config FAIL_PAGE_ALLOC
1902	bool "Fault-injection capability for alloc_pages()"
1903	depends on FAULT_INJECTION
1904	help
1905	  Provide fault-injection capability for alloc_pages().
1906
1907config FAULT_INJECTION_USERCOPY
1908	bool "Fault injection capability for usercopy functions"
1909	depends on FAULT_INJECTION
1910	help
1911	  Provides fault-injection capability to inject failures
1912	  in usercopy functions (copy_from_user(), get_user(), ...).
1913
1914config FAIL_MAKE_REQUEST
1915	bool "Fault-injection capability for disk IO"
1916	depends on FAULT_INJECTION && BLOCK
1917	help
1918	  Provide fault-injection capability for disk IO.
1919
1920config FAIL_IO_TIMEOUT
1921	bool "Fault-injection capability for faking disk interrupts"
1922	depends on FAULT_INJECTION && BLOCK
1923	help
1924	  Provide fault-injection capability on end IO handling. This
1925	  will make the block layer "forget" an interrupt as configured,
1926	  thus exercising the error handling.
1927
1928	  Only works with drivers that use the generic timeout handling,
1929	  for others it won't do anything.
1930
1931config FAIL_FUTEX
1932	bool "Fault-injection capability for futexes"
1933	select DEBUG_FS
1934	depends on FAULT_INJECTION && FUTEX
1935	help
1936	  Provide fault-injection capability for futexes.
1937
1938config FAULT_INJECTION_DEBUG_FS
1939	bool "Debugfs entries for fault-injection capabilities"
1940	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1941	help
1942	  Enable configuration of fault-injection capabilities via debugfs.
1943
1944config FAIL_FUNCTION
1945	bool "Fault-injection capability for functions"
1946	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1947	help
1948	  Provide function-based fault-injection capability.
1949	  This will allow you to override a specific function with a return
1950	  with given return value. As a result, function caller will see
1951	  an error value and have to handle it. This is useful to test the
1952	  error handling in various subsystems.
1953
1954config FAIL_MMC_REQUEST
1955	bool "Fault-injection capability for MMC IO"
1956	depends on FAULT_INJECTION_DEBUG_FS && MMC
1957	help
1958	  Provide fault-injection capability for MMC IO.
1959	  This will make the mmc core return data errors. This is
1960	  useful to test the error handling in the mmc block device
1961	  and to test how the mmc host driver handles retries from
1962	  the block device.
1963
1964config FAIL_SUNRPC
1965	bool "Fault-injection capability for SunRPC"
1966	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1967	help
1968	  Provide fault-injection capability for SunRPC and
1969	  its consumers.
1970
1971config FAULT_INJECTION_STACKTRACE_FILTER
1972	bool "stacktrace filter for fault-injection capabilities"
1973	depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1974	select STACKTRACE
1975	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1976	help
1977	  Provide stacktrace filter for fault-injection capabilities
1978
1979config ARCH_HAS_KCOV
1980	bool
1981	help
1982	  An architecture should select this when it can successfully
1983	  build and run with CONFIG_KCOV. This typically requires
1984	  disabling instrumentation for some early boot code.
1985
1986config CC_HAS_SANCOV_TRACE_PC
1987	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1988
1989
1990config KCOV
1991	bool "Code coverage for fuzzing"
1992	depends on ARCH_HAS_KCOV
1993	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1994	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
1995		   GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
1996	select DEBUG_FS
1997	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1998	select OBJTOOL if HAVE_NOINSTR_HACK
1999	help
2000	  KCOV exposes kernel code coverage information in a form suitable
2001	  for coverage-guided fuzzing (randomized testing).
2002
2003	  If RANDOMIZE_BASE is enabled, PC values will not be stable across
2004	  different machines and across reboots. If you need stable PC values,
2005	  disable RANDOMIZE_BASE.
2006
2007	  For more details, see Documentation/dev-tools/kcov.rst.
2008
2009config KCOV_ENABLE_COMPARISONS
2010	bool "Enable comparison operands collection by KCOV"
2011	depends on KCOV
2012	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2013	help
2014	  KCOV also exposes operands of every comparison in the instrumented
2015	  code along with operand sizes and PCs of the comparison instructions.
2016	  These operands can be used by fuzzing engines to improve the quality
2017	  of fuzzing coverage.
2018
2019config KCOV_INSTRUMENT_ALL
2020	bool "Instrument all code by default"
2021	depends on KCOV
2022	default y
2023	help
2024	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2025	  then you will want to instrument the whole kernel and you should
2026	  say y here. If you are doing more targeted fuzzing (like e.g.
2027	  filesystem fuzzing with AFL) then you will want to enable coverage
2028	  for more specific subsets of files, and should say n here.
2029
2030config KCOV_IRQ_AREA_SIZE
2031	hex "Size of interrupt coverage collection area in words"
2032	depends on KCOV
2033	default 0x40000
2034	help
2035	  KCOV uses preallocated per-cpu areas to collect coverage from
2036	  soft interrupts. This specifies the size of those areas in the
2037	  number of unsigned long words.
2038
2039menuconfig RUNTIME_TESTING_MENU
2040	bool "Runtime Testing"
2041	def_bool y
2042
2043if RUNTIME_TESTING_MENU
2044
2045config TEST_DHRY
2046	tristate "Dhrystone benchmark test"
2047	help
2048	  Enable this to include the Dhrystone 2.1 benchmark.  This test
2049	  calculates the number of Dhrystones per second, and the number of
2050	  DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2051	  by 1757 (the number of Dhrystones per second obtained on the VAX
2052	  11/780, nominally a 1 MIPS machine).
2053
2054	  To run the benchmark, it needs to be enabled explicitly, either from
2055	  the kernel command line (when built-in), or from userspace (when
2056	  built-in or modular.
2057
2058	  Run once during kernel boot:
2059
2060	      test_dhry.run
2061
2062	  Set number of iterations from kernel command line:
2063
2064	      test_dhry.iterations=<n>
2065
2066	  Set number of iterations from userspace:
2067
2068	      echo <n> > /sys/module/test_dhry/parameters/iterations
2069
2070	  Trigger manual run from userspace:
2071
2072	      echo y > /sys/module/test_dhry/parameters/run
2073
2074	  If the number of iterations is <= 0, the test will devise a suitable
2075	  number of iterations (test runs for at least 2s) automatically.
2076	  This process takes ca. 4s.
2077
2078	  If unsure, say N.
2079
2080config LKDTM
2081	tristate "Linux Kernel Dump Test Tool Module"
2082	depends on DEBUG_FS
2083	help
2084	This module enables testing of the different dumping mechanisms by
2085	inducing system failures at predefined crash points.
2086	If you don't need it: say N
2087	Choose M here to compile this code as a module. The module will be
2088	called lkdtm.
2089
2090	Documentation on how to use the module can be found in
2091	Documentation/fault-injection/provoke-crashes.rst
2092
2093config CPUMASK_KUNIT_TEST
2094	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2095	depends on KUNIT
2096	default KUNIT_ALL_TESTS
2097	help
2098	  Enable to turn on cpumask tests, running at boot or module load time.
2099
2100	  For more information on KUnit and unit tests in general, please refer
2101	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2102
2103	  If unsure, say N.
2104
2105config TEST_LIST_SORT
2106	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2107	depends on KUNIT
2108	default KUNIT_ALL_TESTS
2109	help
2110	  Enable this to turn on 'list_sort()' function test. This test is
2111	  executed only once during system boot (so affects only boot time),
2112	  or at module load time.
2113
2114	  If unsure, say N.
2115
2116config TEST_MIN_HEAP
2117	tristate "Min heap test"
2118	depends on DEBUG_KERNEL || m
2119	help
2120	  Enable this to turn on min heap function tests. This test is
2121	  executed only once during system boot (so affects only boot time),
2122	  or at module load time.
2123
2124	  If unsure, say N.
2125
2126config TEST_SORT
2127	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2128	depends on KUNIT
2129	default KUNIT_ALL_TESTS
2130	help
2131	  This option enables the self-test function of 'sort()' at boot,
2132	  or at module load time.
2133
2134	  If unsure, say N.
2135
2136config TEST_DIV64
2137	tristate "64bit/32bit division and modulo test"
2138	depends on DEBUG_KERNEL || m
2139	help
2140	  Enable this to turn on 'do_div()' function test. This test is
2141	  executed only once during system boot (so affects only boot time),
2142	  or at module load time.
2143
2144	  If unsure, say N.
2145
2146config KPROBES_SANITY_TEST
2147	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2148	depends on DEBUG_KERNEL
2149	depends on KPROBES
2150	depends on KUNIT
2151	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2152	default KUNIT_ALL_TESTS
2153	help
2154	  This option provides for testing basic kprobes functionality on
2155	  boot. Samples of kprobe and kretprobe are inserted and
2156	  verified for functionality.
2157
2158	  Say N if you are unsure.
2159
2160config FPROBE_SANITY_TEST
2161	bool "Self test for fprobe"
2162	depends on DEBUG_KERNEL
2163	depends on FPROBE
2164	depends on KUNIT=y
2165	help
2166	  This option will enable testing the fprobe when the system boot.
2167	  A series of tests are made to verify that the fprobe is functioning
2168	  properly.
2169
2170	  Say N if you are unsure.
2171
2172config BACKTRACE_SELF_TEST
2173	tristate "Self test for the backtrace code"
2174	depends on DEBUG_KERNEL
2175	help
2176	  This option provides a kernel module that can be used to test
2177	  the kernel stack backtrace code. This option is not useful
2178	  for distributions or general kernels, but only for kernel
2179	  developers working on architecture code.
2180
2181	  Note that if you want to also test saved backtraces, you will
2182	  have to enable STACKTRACE as well.
2183
2184	  Say N if you are unsure.
2185
2186config TEST_REF_TRACKER
2187	tristate "Self test for reference tracker"
2188	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2189	select REF_TRACKER
2190	help
2191	  This option provides a kernel module performing tests
2192	  using reference tracker infrastructure.
2193
2194	  Say N if you are unsure.
2195
2196config RBTREE_TEST
2197	tristate "Red-Black tree test"
2198	depends on DEBUG_KERNEL
2199	help
2200	  A benchmark measuring the performance of the rbtree library.
2201	  Also includes rbtree invariant checks.
2202
2203config REED_SOLOMON_TEST
2204	tristate "Reed-Solomon library test"
2205	depends on DEBUG_KERNEL || m
2206	select REED_SOLOMON
2207	select REED_SOLOMON_ENC16
2208	select REED_SOLOMON_DEC16
2209	help
2210	  This option enables the self-test function of rslib at boot,
2211	  or at module load time.
2212
2213	  If unsure, say N.
2214
2215config INTERVAL_TREE_TEST
2216	tristate "Interval tree test"
2217	depends on DEBUG_KERNEL
2218	select INTERVAL_TREE
2219	help
2220	  A benchmark measuring the performance of the interval tree library
2221
2222config PERCPU_TEST
2223	tristate "Per cpu operations test"
2224	depends on m && DEBUG_KERNEL
2225	help
2226	  Enable this option to build test module which validates per-cpu
2227	  operations.
2228
2229	  If unsure, say N.
2230
2231config ATOMIC64_SELFTEST
2232	tristate "Perform an atomic64_t self-test"
2233	help
2234	  Enable this option to test the atomic64_t functions at boot or
2235	  at module load time.
2236
2237	  If unsure, say N.
2238
2239config ASYNC_RAID6_TEST
2240	tristate "Self test for hardware accelerated raid6 recovery"
2241	depends on ASYNC_RAID6_RECOV
2242	select ASYNC_MEMCPY
2243	help
2244	  This is a one-shot self test that permutes through the
2245	  recovery of all the possible two disk failure scenarios for a
2246	  N-disk array.  Recovery is performed with the asynchronous
2247	  raid6 recovery routines, and will optionally use an offload
2248	  engine if one is available.
2249
2250	  If unsure, say N.
2251
2252config TEST_HEXDUMP
2253	tristate "Test functions located in the hexdump module at runtime"
2254
2255config STRING_SELFTEST
2256	tristate "Test string functions at runtime"
2257
2258config TEST_STRING_HELPERS
2259	tristate "Test functions located in the string_helpers module at runtime"
2260
2261config TEST_KSTRTOX
2262	tristate "Test kstrto*() family of functions at runtime"
2263
2264config TEST_PRINTF
2265	tristate "Test printf() family of functions at runtime"
2266
2267config TEST_SCANF
2268	tristate "Test scanf() family of functions at runtime"
2269
2270config TEST_BITMAP
2271	tristate "Test bitmap_*() family of functions at runtime"
2272	help
2273	  Enable this option to test the bitmap functions at boot.
2274
2275	  If unsure, say N.
2276
2277config TEST_UUID
2278	tristate "Test functions located in the uuid module at runtime"
2279
2280config TEST_XARRAY
2281	tristate "Test the XArray code at runtime"
2282
2283config TEST_MAPLE_TREE
2284	depends on DEBUG_KERNEL
2285	select DEBUG_MAPLE_TREE
2286	tristate "Test the Maple Tree code at runtime"
2287
2288config TEST_RHASHTABLE
2289	tristate "Perform selftest on resizable hash table"
2290	help
2291	  Enable this option to test the rhashtable functions at boot.
2292
2293	  If unsure, say N.
2294
2295config TEST_IDA
2296	tristate "Perform selftest on IDA functions"
2297
2298config TEST_PARMAN
2299	tristate "Perform selftest on priority array manager"
2300	depends on PARMAN
2301	help
2302	  Enable this option to test priority array manager on boot
2303	  (or module load).
2304
2305	  If unsure, say N.
2306
2307config TEST_IRQ_TIMINGS
2308	bool "IRQ timings selftest"
2309	depends on IRQ_TIMINGS
2310	help
2311	  Enable this option to test the irq timings code on boot.
2312
2313	  If unsure, say N.
2314
2315config TEST_LKM
2316	tristate "Test module loading with 'hello world' module"
2317	depends on m
2318	help
2319	  This builds the "test_module" module that emits "Hello, world"
2320	  on printk when loaded. It is designed to be used for basic
2321	  evaluation of the module loading subsystem (for example when
2322	  validating module verification). It lacks any extra dependencies,
2323	  and will not normally be loaded by the system unless explicitly
2324	  requested by name.
2325
2326	  If unsure, say N.
2327
2328config TEST_BITOPS
2329	tristate "Test module for compilation of bitops operations"
2330	depends on m
2331	help
2332	  This builds the "test_bitops" module that is much like the
2333	  TEST_LKM module except that it does a basic exercise of the
2334	  set/clear_bit macros and get_count_order/long to make sure there are
2335	  no compiler warnings from C=1 sparse checker or -Wextra
2336	  compilations. It has no dependencies and doesn't run or load unless
2337	  explicitly requested by name.  for example: modprobe test_bitops.
2338
2339	  If unsure, say N.
2340
2341config TEST_VMALLOC
2342	tristate "Test module for stress/performance analysis of vmalloc allocator"
2343	default n
2344       depends on MMU
2345	depends on m
2346	help
2347	  This builds the "test_vmalloc" module that should be used for
2348	  stress and performance analysis. So, any new change for vmalloc
2349	  subsystem can be evaluated from performance and stability point
2350	  of view.
2351
2352	  If unsure, say N.
2353
2354config TEST_USER_COPY
2355	tristate "Test user/kernel boundary protections"
2356	depends on m
2357	help
2358	  This builds the "test_user_copy" module that runs sanity checks
2359	  on the copy_to/from_user infrastructure, making sure basic
2360	  user/kernel boundary testing is working. If it fails to load,
2361	  a regression has been detected in the user/kernel memory boundary
2362	  protections.
2363
2364	  If unsure, say N.
2365
2366config TEST_BPF
2367	tristate "Test BPF filter functionality"
2368	depends on m && NET
2369	help
2370	  This builds the "test_bpf" module that runs various test vectors
2371	  against the BPF interpreter or BPF JIT compiler depending on the
2372	  current setting. This is in particular useful for BPF JIT compiler
2373	  development, but also to run regression tests against changes in
2374	  the interpreter code. It also enables test stubs for eBPF maps and
2375	  verifier used by user space verifier testsuite.
2376
2377	  If unsure, say N.
2378
2379config TEST_BLACKHOLE_DEV
2380	tristate "Test blackhole netdev functionality"
2381	depends on m && NET
2382	help
2383	  This builds the "test_blackhole_dev" module that validates the
2384	  data path through this blackhole netdev.
2385
2386	  If unsure, say N.
2387
2388config FIND_BIT_BENCHMARK
2389	tristate "Test find_bit functions"
2390	help
2391	  This builds the "test_find_bit" module that measure find_*_bit()
2392	  functions performance.
2393
2394	  If unsure, say N.
2395
2396config TEST_FIRMWARE
2397	tristate "Test firmware loading via userspace interface"
2398	depends on FW_LOADER
2399	help
2400	  This builds the "test_firmware" module that creates a userspace
2401	  interface for testing firmware loading. This can be used to
2402	  control the triggering of firmware loading without needing an
2403	  actual firmware-using device. The contents can be rechecked by
2404	  userspace.
2405
2406	  If unsure, say N.
2407
2408config TEST_SYSCTL
2409	tristate "sysctl test driver"
2410	depends on PROC_SYSCTL
2411	help
2412	  This builds the "test_sysctl" module. This driver enables to test the
2413	  proc sysctl interfaces available to drivers safely without affecting
2414	  production knobs which might alter system functionality.
2415
2416	  If unsure, say N.
2417
2418config BITFIELD_KUNIT
2419	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2420	depends on KUNIT
2421	default KUNIT_ALL_TESTS
2422	help
2423	  Enable this option to test the bitfield functions at boot.
2424
2425	  KUnit tests run during boot and output the results to the debug log
2426	  in TAP format (http://testanything.org/). Only useful for kernel devs
2427	  running the KUnit test harness, and not intended for inclusion into a
2428	  production build.
2429
2430	  For more information on KUnit and unit tests in general please refer
2431	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2432
2433	  If unsure, say N.
2434
2435config HASH_KUNIT_TEST
2436	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2437	depends on KUNIT
2438	default KUNIT_ALL_TESTS
2439	help
2440	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2441	  integer (<linux/hash.h>) hash functions on boot.
2442
2443	  KUnit tests run during boot and output the results to the debug log
2444	  in TAP format (https://testanything.org/). Only useful for kernel devs
2445	  running the KUnit test harness, and not intended for inclusion into a
2446	  production build.
2447
2448	  For more information on KUnit and unit tests in general please refer
2449	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2450
2451	  This is intended to help people writing architecture-specific
2452	  optimized versions. If unsure, say N.
2453
2454config RESOURCE_KUNIT_TEST
2455	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2456	depends on KUNIT
2457	default KUNIT_ALL_TESTS
2458	help
2459	  This builds the resource API unit test.
2460	  Tests the logic of API provided by resource.c and ioport.h.
2461	  For more information on KUnit and unit tests in general please refer
2462	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2463
2464	  If unsure, say N.
2465
2466config SYSCTL_KUNIT_TEST
2467	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2468	depends on KUNIT
2469	default KUNIT_ALL_TESTS
2470	help
2471	  This builds the proc sysctl unit test, which runs on boot.
2472	  Tests the API contract and implementation correctness of sysctl.
2473	  For more information on KUnit and unit tests in general please refer
2474	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2475
2476	  If unsure, say N.
2477
2478config LIST_KUNIT_TEST
2479	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2480	depends on KUNIT
2481	default KUNIT_ALL_TESTS
2482	help
2483	  This builds the linked list KUnit test suite.
2484	  It tests that the API and basic functionality of the list_head type
2485	  and associated macros.
2486
2487	  KUnit tests run during boot and output the results to the debug log
2488	  in TAP format (https://testanything.org/). Only useful for kernel devs
2489	  running the KUnit test harness, and not intended for inclusion into a
2490	  production build.
2491
2492	  For more information on KUnit and unit tests in general please refer
2493	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2494
2495	  If unsure, say N.
2496
2497config HASHTABLE_KUNIT_TEST
2498	tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2499	depends on KUNIT
2500	default KUNIT_ALL_TESTS
2501	help
2502	  This builds the hashtable KUnit test suite.
2503	  It tests the basic functionality of the API defined in
2504	  include/linux/hashtable.h. For more information on KUnit and
2505	  unit tests in general please refer to the KUnit documentation
2506	  in Documentation/dev-tools/kunit/.
2507
2508	  If unsure, say N.
2509
2510config LINEAR_RANGES_TEST
2511	tristate "KUnit test for linear_ranges"
2512	depends on KUNIT
2513	select LINEAR_RANGES
2514	help
2515	  This builds the linear_ranges unit test, which runs on boot.
2516	  Tests the linear_ranges logic correctness.
2517	  For more information on KUnit and unit tests in general please refer
2518	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2519
2520	  If unsure, say N.
2521
2522config CMDLINE_KUNIT_TEST
2523	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2524	depends on KUNIT
2525	default KUNIT_ALL_TESTS
2526	help
2527	  This builds the cmdline API unit test.
2528	  Tests the logic of API provided by cmdline.c.
2529	  For more information on KUnit and unit tests in general please refer
2530	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2531
2532	  If unsure, say N.
2533
2534config BITS_TEST
2535	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2536	depends on KUNIT
2537	default KUNIT_ALL_TESTS
2538	help
2539	  This builds the bits unit test.
2540	  Tests the logic of macros defined in bits.h.
2541	  For more information on KUnit and unit tests in general please refer
2542	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2543
2544	  If unsure, say N.
2545
2546config SLUB_KUNIT_TEST
2547	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2548	depends on SLUB_DEBUG && KUNIT
2549	default KUNIT_ALL_TESTS
2550	help
2551	  This builds SLUB allocator unit test.
2552	  Tests SLUB cache debugging functionality.
2553	  For more information on KUnit and unit tests in general please refer
2554	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2555
2556	  If unsure, say N.
2557
2558config RATIONAL_KUNIT_TEST
2559	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2560	depends on KUNIT && RATIONAL
2561	default KUNIT_ALL_TESTS
2562	help
2563	  This builds the rational math unit test.
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 MEMCPY_KUNIT_TEST
2570	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2571	depends on KUNIT
2572	default KUNIT_ALL_TESTS
2573	help
2574	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2575	  For more information on KUnit and unit tests in general please refer
2576	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2577
2578	  If unsure, say N.
2579
2580config MEMCPY_SLOW_KUNIT_TEST
2581	bool "Include exhaustive memcpy tests"
2582	depends on MEMCPY_KUNIT_TEST
2583	default y
2584	help
2585	  Some memcpy tests are quite exhaustive in checking for overlaps
2586	  and bit ranges. These can be very slow, so they are split out
2587	  as a separate config, in case they need to be disabled.
2588
2589config IS_SIGNED_TYPE_KUNIT_TEST
2590	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2591	depends on KUNIT
2592	default KUNIT_ALL_TESTS
2593	help
2594	  Builds unit tests for the is_signed_type() macro.
2595
2596	  For more information on KUnit and unit tests in general please refer
2597	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2598
2599	  If unsure, say N.
2600
2601config OVERFLOW_KUNIT_TEST
2602	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2603	depends on KUNIT
2604	default KUNIT_ALL_TESTS
2605	help
2606	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2607	  related functions.
2608
2609	  For more information on KUnit and unit tests in general please refer
2610	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2611
2612	  If unsure, say N.
2613
2614config STACKINIT_KUNIT_TEST
2615	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2616	depends on KUNIT
2617	default KUNIT_ALL_TESTS
2618	help
2619	  Test if the kernel is zero-initializing stack variables and
2620	  padding. Coverage is controlled by compiler flags,
2621	  CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2622	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2623	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2624
2625config FORTIFY_KUNIT_TEST
2626	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2627	depends on KUNIT && FORTIFY_SOURCE
2628	default KUNIT_ALL_TESTS
2629	help
2630	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2631	  by the str*() and mem*() family of functions. For testing runtime
2632	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2633
2634config HW_BREAKPOINT_KUNIT_TEST
2635	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2636	depends on HAVE_HW_BREAKPOINT
2637	depends on KUNIT=y
2638	default KUNIT_ALL_TESTS
2639	help
2640	  Tests for hw_breakpoint constraints accounting.
2641
2642	  If unsure, say N.
2643
2644config STRSCPY_KUNIT_TEST
2645	tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2646	depends on KUNIT
2647	default KUNIT_ALL_TESTS
2648
2649config SIPHASH_KUNIT_TEST
2650	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2651	depends on KUNIT
2652	default KUNIT_ALL_TESTS
2653	help
2654	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2655	  functions on boot (or module load).
2656
2657	  This is intended to help people writing architecture-specific
2658	  optimized versions.  If unsure, say N.
2659
2660config TEST_UDELAY
2661	tristate "udelay test driver"
2662	help
2663	  This builds the "udelay_test" module that helps to make sure
2664	  that udelay() is working properly.
2665
2666	  If unsure, say N.
2667
2668config TEST_STATIC_KEYS
2669	tristate "Test static keys"
2670	depends on m
2671	help
2672	  Test the static key interfaces.
2673
2674	  If unsure, say N.
2675
2676config TEST_DYNAMIC_DEBUG
2677	tristate "Test DYNAMIC_DEBUG"
2678	depends on DYNAMIC_DEBUG
2679	help
2680	  This module registers a tracer callback to count enabled
2681	  pr_debugs in a 'do_debugging' function, then alters their
2682	  enablements, calls the function, and compares counts.
2683
2684	  If unsure, say N.
2685
2686config TEST_KMOD
2687	tristate "kmod stress tester"
2688	depends on m
2689	depends on NETDEVICES && NET_CORE && INET # for TUN
2690	depends on BLOCK
2691	depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2692	select TEST_LKM
2693	select XFS_FS
2694	select TUN
2695	select BTRFS_FS
2696	help
2697	  Test the kernel's module loading mechanism: kmod. kmod implements
2698	  support to load modules using the Linux kernel's usermode helper.
2699	  This test provides a series of tests against kmod.
2700
2701	  Although technically you can either build test_kmod as a module or
2702	  into the kernel we disallow building it into the kernel since
2703	  it stress tests request_module() and this will very likely cause
2704	  some issues by taking over precious threads available from other
2705	  module load requests, ultimately this could be fatal.
2706
2707	  To run tests run:
2708
2709	  tools/testing/selftests/kmod/kmod.sh --help
2710
2711	  If unsure, say N.
2712
2713config TEST_DEBUG_VIRTUAL
2714	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2715	depends on DEBUG_VIRTUAL
2716	help
2717	  Test the kernel's ability to detect incorrect calls to
2718	  virt_to_phys() done against the non-linear part of the
2719	  kernel's virtual address map.
2720
2721	  If unsure, say N.
2722
2723config TEST_MEMCAT_P
2724	tristate "Test memcat_p() helper function"
2725	help
2726	  Test the memcat_p() helper for correctly merging two
2727	  pointer arrays together.
2728
2729	  If unsure, say N.
2730
2731config TEST_LIVEPATCH
2732	tristate "Test livepatching"
2733	default n
2734	depends on DYNAMIC_DEBUG
2735	depends on LIVEPATCH
2736	depends on m
2737	help
2738	  Test kernel livepatching features for correctness.  The tests will
2739	  load test modules that will be livepatched in various scenarios.
2740
2741	  To run all the livepatching tests:
2742
2743	  make -C tools/testing/selftests TARGETS=livepatch run_tests
2744
2745	  Alternatively, individual tests may be invoked:
2746
2747	  tools/testing/selftests/livepatch/test-callbacks.sh
2748	  tools/testing/selftests/livepatch/test-livepatch.sh
2749	  tools/testing/selftests/livepatch/test-shadow-vars.sh
2750
2751	  If unsure, say N.
2752
2753config TEST_OBJAGG
2754	tristate "Perform selftest on object aggreration manager"
2755	default n
2756	depends on OBJAGG
2757	help
2758	  Enable this option to test object aggregation manager on boot
2759	  (or module load).
2760
2761config TEST_MEMINIT
2762	tristate "Test heap/page initialization"
2763	help
2764	  Test if the kernel is zero-initializing heap and page allocations.
2765	  This can be useful to test init_on_alloc and init_on_free features.
2766
2767	  If unsure, say N.
2768
2769config TEST_HMM
2770	tristate "Test HMM (Heterogeneous Memory Management)"
2771	depends on TRANSPARENT_HUGEPAGE
2772	depends on DEVICE_PRIVATE
2773	select HMM_MIRROR
2774	select MMU_NOTIFIER
2775	help
2776	  This is a pseudo device driver solely for testing HMM.
2777	  Say M here if you want to build the HMM test module.
2778	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2779
2780	  If unsure, say N.
2781
2782config TEST_FREE_PAGES
2783	tristate "Test freeing pages"
2784	help
2785	  Test that a memory leak does not occur due to a race between
2786	  freeing a block of pages and a speculative page reference.
2787	  Loading this module is safe if your kernel has the bug fixed.
2788	  If the bug is not fixed, it will leak gigabytes of memory and
2789	  probably OOM your system.
2790
2791config TEST_FPU
2792	tristate "Test floating point operations in kernel space"
2793	depends on X86 && !KCOV_INSTRUMENT_ALL
2794	help
2795	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2796	  which will trigger a sequence of floating point operations. This is used
2797	  for self-testing floating point control register setting in
2798	  kernel_fpu_begin().
2799
2800	  If unsure, say N.
2801
2802config TEST_CLOCKSOURCE_WATCHDOG
2803	tristate "Test clocksource watchdog in kernel space"
2804	depends on CLOCKSOURCE_WATCHDOG
2805	help
2806	  Enable this option to create a kernel module that will trigger
2807	  a test of the clocksource watchdog.  This module may be loaded
2808	  via modprobe or insmod in which case it will run upon being
2809	  loaded, or it may be built in, in which case it will run
2810	  shortly after boot.
2811
2812	  If unsure, say N.
2813
2814endif # RUNTIME_TESTING_MENU
2815
2816config ARCH_USE_MEMTEST
2817	bool
2818	help
2819	  An architecture should select this when it uses early_memtest()
2820	  during boot process.
2821
2822config MEMTEST
2823	bool "Memtest"
2824	depends on ARCH_USE_MEMTEST
2825	help
2826	  This option adds a kernel parameter 'memtest', which allows memtest
2827	  to be set and executed.
2828	        memtest=0, mean disabled; -- default
2829	        memtest=1, mean do 1 test pattern;
2830	        ...
2831	        memtest=17, mean do 17 test patterns.
2832	  If you are unsure how to answer this question, answer N.
2833
2834
2835
2836config HYPERV_TESTING
2837	bool "Microsoft Hyper-V driver testing"
2838	default n
2839	depends on HYPERV && DEBUG_FS
2840	help
2841	  Select this option to enable Hyper-V vmbus testing.
2842
2843endmenu # "Kernel Testing and Coverage"
2844
2845menu "Rust hacking"
2846
2847config RUST_DEBUG_ASSERTIONS
2848	bool "Debug assertions"
2849	depends on RUST
2850	help
2851	  Enables rustc's `-Cdebug-assertions` codegen option.
2852
2853	  This flag lets you turn `cfg(debug_assertions)` conditional
2854	  compilation on or off. This can be used to enable extra debugging
2855	  code in development but not in production. For example, it controls
2856	  the behavior of the standard library's `debug_assert!` macro.
2857
2858	  Note that this will apply to all Rust code, including `core`.
2859
2860	  If unsure, say N.
2861
2862config RUST_OVERFLOW_CHECKS
2863	bool "Overflow checks"
2864	default y
2865	depends on RUST
2866	help
2867	  Enables rustc's `-Coverflow-checks` codegen option.
2868
2869	  This flag allows you to control the behavior of runtime integer
2870	  overflow. When overflow-checks are enabled, a Rust panic will occur
2871	  on overflow.
2872
2873	  Note that this will apply to all Rust code, including `core`.
2874
2875	  If unsure, say Y.
2876
2877config RUST_BUILD_ASSERT_ALLOW
2878	bool "Allow unoptimized build-time assertions"
2879	depends on RUST
2880	help
2881	  Controls how are `build_error!` and `build_assert!` handled during build.
2882
2883	  If calls to them exist in the binary, it may indicate a violated invariant
2884	  or that the optimizer failed to verify the invariant during compilation.
2885
2886	  This should not happen, thus by default the build is aborted. However,
2887	  as an escape hatch, you can choose Y here to ignore them during build
2888	  and let the check be carried at runtime (with `panic!` being called if
2889	  the check fails).
2890
2891	  If unsure, say N.
2892
2893endmenu # "Rust"
2894
2895endmenu # Kernel hacking
2896