xref: /linux-6.15/lib/Kconfig.debug (revision a8e35fec)
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
234choice
235	prompt "Debug information"
236	depends on DEBUG_KERNEL
237	help
238	  Selecting something other than "None" results in a kernel image
239	  that will include debugging info resulting in a larger kernel image.
240	  This adds debug symbols to the kernel and modules (gcc -g), and
241	  is needed if you intend to use kernel crashdump or binary object
242	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
243
244	  Choose which version of DWARF debug info to emit. If unsure,
245	  select "Toolchain default".
246
247config DEBUG_INFO_NONE
248	bool "Disable debug information"
249	help
250	  Do not build the kernel with debugging information, which will
251	  result in a faster and smaller build.
252
253config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
254	bool "Rely on the toolchain's implicit default DWARF version"
255	select DEBUG_INFO
256	help
257	  The implicit default version of DWARF debug info produced by a
258	  toolchain changes over time.
259
260	  This can break consumers of the debug info that haven't upgraded to
261	  support newer revisions, and prevent testing newer versions, but
262	  those should be less common scenarios.
263
264config DEBUG_INFO_DWARF4
265	bool "Generate DWARF Version 4 debuginfo"
266	select DEBUG_INFO
267	help
268	  Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+.
269
270	  If you have consumers of DWARF debug info that are not ready for
271	  newer revisions of DWARF, you may wish to choose this or have your
272	  config select this.
273
274config DEBUG_INFO_DWARF5
275	bool "Generate DWARF Version 5 debuginfo"
276	select DEBUG_INFO
277	depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
278	help
279	  Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
280	  5.0+ accepts the -gdwarf-5 flag but only had partial support for some
281	  draft features until 7.0), and gdb 8.0+.
282
283	  Changes to the structure of debug info in Version 5 allow for around
284	  15-18% savings in resulting image and debug info section sizes as
285	  compared to DWARF Version 4. DWARF Version 5 standardizes previous
286	  extensions such as accelerators for symbol indexing and the format
287	  for fission (.dwo/.dwp) files. Users may not want to select this
288	  config if they rely on tooling that has not yet been updated to
289	  support DWARF Version 5.
290
291endchoice # "Debug information"
292
293if DEBUG_INFO
294
295config DEBUG_INFO_REDUCED
296	bool "Reduce debugging information"
297	help
298	  If you say Y here gcc is instructed to generate less debugging
299	  information for structure types. This means that tools that
300	  need full debugging information (like kgdb or systemtap) won't
301	  be happy. But if you merely need debugging information to
302	  resolve line numbers there is no loss. Advantage is that
303	  build directory object sizes shrink dramatically over a full
304	  DEBUG_INFO build and compile times are reduced too.
305	  Only works with newer gcc versions.
306
307config DEBUG_INFO_COMPRESSED
308	bool "Compressed debugging information"
309	depends on $(cc-option,-gz=zlib)
310	depends on $(ld-option,--compress-debug-sections=zlib)
311	help
312	  Compress the debug information using zlib.  Requires GCC 5.0+ or Clang
313	  5.0+, binutils 2.26+, and zlib.
314
315	  Users of dpkg-deb via scripts/package/builddeb may find an increase in
316	  size of their debug .deb packages with this config set, due to the
317	  debug info being compressed with zlib, then the object files being
318	  recompressed with a different compression scheme. But this is still
319	  preferable to setting $KDEB_COMPRESS to "none" which would be even
320	  larger.
321
322config DEBUG_INFO_SPLIT
323	bool "Produce split debuginfo in .dwo files"
324	depends on $(cc-option,-gsplit-dwarf)
325	help
326	  Generate debug info into separate .dwo files. This significantly
327	  reduces the build directory size for builds with DEBUG_INFO,
328	  because it stores the information only once on disk in .dwo
329	  files instead of multiple times in object files and executables.
330	  In addition the debug information is also compressed.
331
332	  Requires recent gcc (4.7+) and recent gdb/binutils.
333	  Any tool that packages or reads debug information would need
334	  to know about the .dwo files and include them.
335	  Incompatible with older versions of ccache.
336
337config DEBUG_INFO_BTF
338	bool "Generate BTF typeinfo"
339	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
340	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
341	depends on BPF_SYSCALL
342	depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
343	help
344	  Generate deduplicated BTF type information from DWARF debug info.
345	  Turning this on expects presence of pahole tool, which will convert
346	  DWARF type info into equivalent deduplicated BTF type info.
347
348config PAHOLE_HAS_SPLIT_BTF
349	def_bool PAHOLE_VERSION >= 119
350
351config PAHOLE_HAS_BTF_TAG
352	def_bool PAHOLE_VERSION >= 123
353	depends on CC_IS_CLANG
354	help
355	  Decide whether pahole emits btf_tag attributes (btf_type_tag and
356	  btf_decl_tag) or not. Currently only clang compiler implements
357	  these attributes, so make the config depend on CC_IS_CLANG.
358
359config DEBUG_INFO_BTF_MODULES
360	def_bool y
361	depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
362	help
363	  Generate compact split BTF type information for kernel modules.
364
365config MODULE_ALLOW_BTF_MISMATCH
366	bool "Allow loading modules with non-matching BTF type info"
367	depends on DEBUG_INFO_BTF_MODULES
368	help
369	  For modules whose split BTF does not match vmlinux, load without
370	  BTF rather than refusing to load. The default behavior with
371	  module BTF enabled is to reject modules with such mismatches;
372	  this option will still load module BTF where possible but ignore
373	  it when a mismatch is found.
374
375config GDB_SCRIPTS
376	bool "Provide GDB scripts for kernel debugging"
377	help
378	  This creates the required links to GDB helper scripts in the
379	  build directory. If you load vmlinux into gdb, the helper
380	  scripts will be automatically imported by gdb as well, and
381	  additional functions are available to analyze a Linux kernel
382	  instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
383	  for further details.
384
385endif # DEBUG_INFO
386
387config FRAME_WARN
388	int "Warn for stack frames larger than"
389	range 0 8192
390	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
391	default 2048 if PARISC
392	default 1536 if (!64BIT && XTENSA)
393	default 1024 if !64BIT
394	default 2048 if 64BIT
395	help
396	  Tell gcc to warn at build time for stack frames larger than this.
397	  Setting this too low will cause a lot of warnings.
398	  Setting it to 0 disables the warning.
399
400config STRIP_ASM_SYMS
401	bool "Strip assembler-generated symbols during link"
402	default n
403	help
404	  Strip internal assembler-generated symbols during a link (symbols
405	  that look like '.Lxxx') so they don't pollute the output of
406	  get_wchan() and suchlike.
407
408config READABLE_ASM
409	bool "Generate readable assembler code"
410	depends on DEBUG_KERNEL
411	depends on CC_IS_GCC
412	help
413	  Disable some compiler optimizations that tend to generate human unreadable
414	  assembler output. This may make the kernel slightly slower, but it helps
415	  to keep kernel developers who have to stare a lot at assembler listings
416	  sane.
417
418config HEADERS_INSTALL
419	bool "Install uapi headers to usr/include"
420	depends on !UML
421	help
422	  This option will install uapi headers (headers exported to user-space)
423	  into the usr/include directory for use during the kernel build.
424	  This is unneeded for building the kernel itself, but needed for some
425	  user-space program samples. It is also needed by some features such
426	  as uapi header sanity checks.
427
428config DEBUG_SECTION_MISMATCH
429	bool "Enable full Section mismatch analysis"
430	depends on CC_IS_GCC
431	help
432	  The section mismatch analysis checks if there are illegal
433	  references from one section to another section.
434	  During linktime or runtime, some sections are dropped;
435	  any use of code/data previously in these sections would
436	  most likely result in an oops.
437	  In the code, functions and variables are annotated with
438	  __init,, etc. (see the full list in include/linux/init.h),
439	  which results in the code/data being placed in specific sections.
440	  The section mismatch analysis is always performed after a full
441	  kernel build, and enabling this option causes the following
442	  additional step to occur:
443	  - Add the option -fno-inline-functions-called-once to gcc commands.
444	    When inlining a function annotated with __init in a non-init
445	    function, we would lose the section information and thus
446	    the analysis would not catch the illegal reference.
447	    This option tells gcc to inline less (but it does result in
448	    a larger kernel).
449
450config SECTION_MISMATCH_WARN_ONLY
451	bool "Make section mismatch errors non-fatal"
452	default y
453	help
454	  If you say N here, the build process will fail if there are any
455	  section mismatch, instead of just throwing warnings.
456
457	  If unsure, say Y.
458
459config DEBUG_FORCE_FUNCTION_ALIGN_64B
460	bool "Force all function address 64B aligned"
461	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
462	help
463	  There are cases that a commit from one domain changes the function
464	  address alignment of other domains, and cause magic performance
465	  bump (regression or improvement). Enable this option will help to
466	  verify if the bump is caused by function alignment changes, while
467	  it will slightly increase the kernel size and affect icache usage.
468
469	  It is mainly for debug and performance tuning use.
470
471#
472# Select this config option from the architecture Kconfig, if it
473# is preferred to always offer frame pointers as a config
474# option on the architecture (regardless of KERNEL_DEBUG):
475#
476config ARCH_WANT_FRAME_POINTERS
477	bool
478
479config FRAME_POINTER
480	bool "Compile the kernel with frame pointers"
481	depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
482	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
483	help
484	  If you say Y here the resulting kernel image will be slightly
485	  larger and slower, but it gives very useful debugging information
486	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
487
488config OBJTOOL
489	bool
490
491config STACK_VALIDATION
492	bool "Compile-time stack metadata validation"
493	depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
494	select OBJTOOL
495	default n
496	help
497	  Validate frame pointer rules at compile-time.  This helps ensure that
498	  runtime stack traces are more reliable.
499
500	  For more information, see
501	  tools/objtool/Documentation/stack-validation.txt.
502
503config NOINSTR_VALIDATION
504	bool
505	depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
506	select OBJTOOL
507	default y
508
509config VMLINUX_MAP
510	bool "Generate vmlinux.map file when linking"
511	depends on EXPERT
512	help
513	  Selecting this option will pass "-Map=vmlinux.map" to ld
514	  when linking vmlinux. That file can be useful for verifying
515	  and debugging magic section games, and for seeing which
516	  pieces of code get eliminated with
517	  CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
518
519config DEBUG_FORCE_WEAK_PER_CPU
520	bool "Force weak per-cpu definitions"
521	depends on DEBUG_KERNEL
522	help
523	  s390 and alpha require percpu variables in modules to be
524	  defined weak to work around addressing range issue which
525	  puts the following two restrictions on percpu variable
526	  definitions.
527
528	  1. percpu symbols must be unique whether static or not
529	  2. percpu variables can't be defined inside a function
530
531	  To ensure that generic code follows the above rules, this
532	  option forces all percpu variables to be defined as weak.
533
534endmenu # "Compiler options"
535
536menu "Generic Kernel Debugging Instruments"
537
538config MAGIC_SYSRQ
539	bool "Magic SysRq key"
540	depends on !UML
541	help
542	  If you say Y here, you will have some control over the system even
543	  if the system crashes for example during kernel debugging (e.g., you
544	  will be able to flush the buffer cache to disk, reboot the system
545	  immediately or dump some status information). This is accomplished
546	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
547	  also works on a serial console (on PC hardware at least), if you
548	  send a BREAK and then within 5 seconds a command keypress. The
549	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
550	  Don't say Y unless you really know what this hack does.
551
552config MAGIC_SYSRQ_DEFAULT_ENABLE
553	hex "Enable magic SysRq key functions by default"
554	depends on MAGIC_SYSRQ
555	default 0x1
556	help
557	  Specifies which SysRq key functions are enabled by default.
558	  This may be set to 1 or 0 to enable or disable them all, or
559	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
560
561config MAGIC_SYSRQ_SERIAL
562	bool "Enable magic SysRq key over serial"
563	depends on MAGIC_SYSRQ
564	default y
565	help
566	  Many embedded boards have a disconnected TTL level serial which can
567	  generate some garbage that can lead to spurious false sysrq detects.
568	  This option allows you to decide whether you want to enable the
569	  magic SysRq key.
570
571config MAGIC_SYSRQ_SERIAL_SEQUENCE
572	string "Char sequence that enables magic SysRq over serial"
573	depends on MAGIC_SYSRQ_SERIAL
574	default ""
575	help
576	  Specifies a sequence of characters that can follow BREAK to enable
577	  SysRq on a serial console.
578
579	  If unsure, leave an empty string and the option will not be enabled.
580
581config DEBUG_FS
582	bool "Debug Filesystem"
583	help
584	  debugfs is a virtual file system that kernel developers use to put
585	  debugging files into.  Enable this option to be able to read and
586	  write to these files.
587
588	  For detailed documentation on the debugfs API, see
589	  Documentation/filesystems/.
590
591	  If unsure, say N.
592
593choice
594	prompt "Debugfs default access"
595	depends on DEBUG_FS
596	default DEBUG_FS_ALLOW_ALL
597	help
598	  This selects the default access restrictions for debugfs.
599	  It can be overridden with kernel command line option
600	  debugfs=[on,no-mount,off]. The restrictions apply for API access
601	  and filesystem registration.
602
603config DEBUG_FS_ALLOW_ALL
604	bool "Access normal"
605	help
606	  No restrictions apply. Both API and filesystem registration
607	  is on. This is the normal default operation.
608
609config DEBUG_FS_DISALLOW_MOUNT
610	bool "Do not register debugfs as filesystem"
611	help
612	  The API is open but filesystem is not loaded. Clients can still do
613	  their work and read with debug tools that do not need
614	  debugfs filesystem.
615
616config DEBUG_FS_ALLOW_NONE
617	bool "No access"
618	help
619	  Access is off. Clients get -PERM when trying to create nodes in
620	  debugfs tree and debugfs is not registered as a filesystem.
621	  Client can then back-off or continue without debugfs access.
622
623endchoice
624
625source "lib/Kconfig.kgdb"
626source "lib/Kconfig.ubsan"
627source "lib/Kconfig.kcsan"
628
629endmenu
630
631menu "Networking Debugging"
632
633source "net/Kconfig.debug"
634
635endmenu # "Networking Debugging"
636
637menu "Memory Debugging"
638
639source "mm/Kconfig.debug"
640
641config DEBUG_OBJECTS
642	bool "Debug object operations"
643	depends on DEBUG_KERNEL
644	help
645	  If you say Y here, additional code will be inserted into the
646	  kernel to track the life time of various objects and validate
647	  the operations on those objects.
648
649config DEBUG_OBJECTS_SELFTEST
650	bool "Debug objects selftest"
651	depends on DEBUG_OBJECTS
652	help
653	  This enables the selftest of the object debug code.
654
655config DEBUG_OBJECTS_FREE
656	bool "Debug objects in freed memory"
657	depends on DEBUG_OBJECTS
658	help
659	  This enables checks whether a k/v free operation frees an area
660	  which contains an object which has not been deactivated
661	  properly. This can make kmalloc/kfree-intensive workloads
662	  much slower.
663
664config DEBUG_OBJECTS_TIMERS
665	bool "Debug timer objects"
666	depends on DEBUG_OBJECTS
667	help
668	  If you say Y here, additional code will be inserted into the
669	  timer routines to track the life time of timer objects and
670	  validate the timer operations.
671
672config DEBUG_OBJECTS_WORK
673	bool "Debug work objects"
674	depends on DEBUG_OBJECTS
675	help
676	  If you say Y here, additional code will be inserted into the
677	  work queue routines to track the life time of work objects and
678	  validate the work operations.
679
680config DEBUG_OBJECTS_RCU_HEAD
681	bool "Debug RCU callbacks objects"
682	depends on DEBUG_OBJECTS
683	help
684	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
685
686config DEBUG_OBJECTS_PERCPU_COUNTER
687	bool "Debug percpu counter objects"
688	depends on DEBUG_OBJECTS
689	help
690	  If you say Y here, additional code will be inserted into the
691	  percpu counter routines to track the life time of percpu counter
692	  objects and validate the percpu counter operations.
693
694config DEBUG_OBJECTS_ENABLE_DEFAULT
695	int "debug_objects bootup default value (0-1)"
696	range 0 1
697	default "1"
698	depends on DEBUG_OBJECTS
699	help
700	  Debug objects boot parameter default value
701
702config DEBUG_SLAB
703	bool "Debug slab memory allocations"
704	depends on DEBUG_KERNEL && SLAB
705	help
706	  Say Y here to have the kernel do limited verification on memory
707	  allocation as well as poisoning memory on free to catch use of freed
708	  memory. This can make kmalloc/kfree-intensive workloads much slower.
709
710config SLUB_DEBUG_ON
711	bool "SLUB debugging on by default"
712	depends on SLUB && SLUB_DEBUG
713	default n
714	help
715	  Boot with debugging on by default. SLUB boots by default with
716	  the runtime debug capabilities switched off. Enabling this is
717	  equivalent to specifying the "slub_debug" parameter on boot.
718	  There is no support for more fine grained debug control like
719	  possible with slub_debug=xxx. SLUB debugging may be switched
720	  off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
721	  "slub_debug=-".
722
723config SLUB_STATS
724	default n
725	bool "Enable SLUB performance statistics"
726	depends on SLUB && SYSFS
727	help
728	  SLUB statistics are useful to debug SLUBs allocation behavior in
729	  order find ways to optimize the allocator. This should never be
730	  enabled for production use since keeping statistics slows down
731	  the allocator by a few percentage points. The slabinfo command
732	  supports the determination of the most active slabs to figure
733	  out which slabs are relevant to a particular load.
734	  Try running: slabinfo -DA
735
736config HAVE_DEBUG_KMEMLEAK
737	bool
738
739config DEBUG_KMEMLEAK
740	bool "Kernel memory leak detector"
741	depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
742	select DEBUG_FS
743	select STACKTRACE if STACKTRACE_SUPPORT
744	select KALLSYMS
745	select CRC32
746	help
747	  Say Y here if you want to enable the memory leak
748	  detector. The memory allocation/freeing is traced in a way
749	  similar to the Boehm's conservative garbage collector, the
750	  difference being that the orphan objects are not freed but
751	  only shown in /sys/kernel/debug/kmemleak. Enabling this
752	  feature will introduce an overhead to memory
753	  allocations. See Documentation/dev-tools/kmemleak.rst for more
754	  details.
755
756	  Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
757	  of finding leaks due to the slab objects poisoning.
758
759	  In order to access the kmemleak file, debugfs needs to be
760	  mounted (usually at /sys/kernel/debug).
761
762config DEBUG_KMEMLEAK_MEM_POOL_SIZE
763	int "Kmemleak memory pool size"
764	depends on DEBUG_KMEMLEAK
765	range 200 1000000
766	default 16000
767	help
768	  Kmemleak must track all the memory allocations to avoid
769	  reporting false positives. Since memory may be allocated or
770	  freed before kmemleak is fully initialised, use a static pool
771	  of metadata objects to track such callbacks. After kmemleak is
772	  fully initialised, this memory pool acts as an emergency one
773	  if slab allocations fail.
774
775config DEBUG_KMEMLEAK_TEST
776	tristate "Simple test for the kernel memory leak detector"
777	depends on DEBUG_KMEMLEAK && m
778	help
779	  This option enables a module that explicitly leaks memory.
780
781	  If unsure, say N.
782
783config DEBUG_KMEMLEAK_DEFAULT_OFF
784	bool "Default kmemleak to off"
785	depends on DEBUG_KMEMLEAK
786	help
787	  Say Y here to disable kmemleak by default. It can then be enabled
788	  on the command line via kmemleak=on.
789
790config DEBUG_KMEMLEAK_AUTO_SCAN
791	bool "Enable kmemleak auto scan thread on boot up"
792	default y
793	depends on DEBUG_KMEMLEAK
794	help
795	  Depending on the cpu, kmemleak scan may be cpu intensive and can
796	  stall user tasks at times. This option enables/disables automatic
797	  kmemleak scan at boot up.
798
799	  Say N here to disable kmemleak auto scan thread to stop automatic
800	  scanning. Disabling this option disables automatic reporting of
801	  memory leaks.
802
803	  If unsure, say Y.
804
805config DEBUG_STACK_USAGE
806	bool "Stack utilization instrumentation"
807	depends on DEBUG_KERNEL && !IA64
808	help
809	  Enables the display of the minimum amount of free stack which each
810	  task has ever had available in the sysrq-T and sysrq-P debug output.
811
812	  This option will slow down process creation somewhat.
813
814config SCHED_STACK_END_CHECK
815	bool "Detect stack corruption on calls to schedule()"
816	depends on DEBUG_KERNEL
817	default n
818	help
819	  This option checks for a stack overrun on calls to schedule().
820	  If the stack end location is found to be over written always panic as
821	  the content of the corrupted region can no longer be trusted.
822	  This is to ensure no erroneous behaviour occurs which could result in
823	  data corruption or a sporadic crash at a later stage once the region
824	  is examined. The runtime overhead introduced is minimal.
825
826config ARCH_HAS_DEBUG_VM_PGTABLE
827	bool
828	help
829	  An architecture should select this when it can successfully
830	  build and run DEBUG_VM_PGTABLE.
831
832config DEBUG_VM
833	bool "Debug VM"
834	depends on DEBUG_KERNEL
835	help
836	  Enable this to turn on extended checks in the virtual-memory system
837	  that may impact performance.
838
839	  If unsure, say N.
840
841config DEBUG_VM_VMACACHE
842	bool "Debug VMA caching"
843	depends on DEBUG_VM
844	help
845	  Enable this to turn on VMA caching debug information. Doing so
846	  can cause significant overhead, so only enable it in non-production
847	  environments.
848
849	  If unsure, say N.
850
851config DEBUG_VM_RB
852	bool "Debug VM red-black trees"
853	depends on DEBUG_VM
854	help
855	  Enable VM red-black tree debugging information and extra validations.
856
857	  If unsure, say N.
858
859config DEBUG_VM_PGFLAGS
860	bool "Debug page-flags operations"
861	depends on DEBUG_VM
862	help
863	  Enables extra validation on page flags operations.
864
865	  If unsure, say N.
866
867config DEBUG_VM_PGTABLE
868	bool "Debug arch page table for semantics compliance"
869	depends on MMU
870	depends on ARCH_HAS_DEBUG_VM_PGTABLE
871	default y if DEBUG_VM
872	help
873	  This option provides a debug method which can be used to test
874	  architecture page table helper functions on various platforms in
875	  verifying if they comply with expected generic MM semantics. This
876	  will help architecture code in making sure that any changes or
877	  new additions of these helpers still conform to expected
878	  semantics of the generic MM. Platforms will have to opt in for
879	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
880
881	  If unsure, say N.
882
883config ARCH_HAS_DEBUG_VIRTUAL
884	bool
885
886config DEBUG_VIRTUAL
887	bool "Debug VM translations"
888	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
889	help
890	  Enable some costly sanity checks in virtual to page code. This can
891	  catch mistakes with virt_to_page() and friends.
892
893	  If unsure, say N.
894
895config DEBUG_NOMMU_REGIONS
896	bool "Debug the global anon/private NOMMU mapping region tree"
897	depends on DEBUG_KERNEL && !MMU
898	help
899	  This option causes the global tree of anonymous and private mapping
900	  regions to be regularly checked for invalid topology.
901
902config DEBUG_MEMORY_INIT
903	bool "Debug memory initialisation" if EXPERT
904	default !EXPERT
905	help
906	  Enable this for additional checks during memory initialisation.
907	  The sanity checks verify aspects of the VM such as the memory model
908	  and other information provided by the architecture. Verbose
909	  information will be printed at KERN_DEBUG loglevel depending
910	  on the mminit_loglevel= command-line option.
911
912	  If unsure, say Y
913
914config MEMORY_NOTIFIER_ERROR_INJECT
915	tristate "Memory hotplug notifier error injection module"
916	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
917	help
918	  This option provides the ability to inject artificial errors to
919	  memory hotplug notifier chain callbacks.  It is controlled through
920	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
921
922	  If the notifier call chain should be failed with some events
923	  notified, write the error code to "actions/<notifier event>/error".
924
925	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
926
927	  # cd /sys/kernel/debug/notifier-error-inject/memory
928	  # echo -12 > actions/MEM_GOING_OFFLINE/error
929	  # echo offline > /sys/devices/system/memory/memoryXXX/state
930	  bash: echo: write error: Cannot allocate memory
931
932	  To compile this code as a module, choose M here: the module will
933	  be called memory-notifier-error-inject.
934
935	  If unsure, say N.
936
937config DEBUG_PER_CPU_MAPS
938	bool "Debug access to per_cpu maps"
939	depends on DEBUG_KERNEL
940	depends on SMP
941	help
942	  Say Y to verify that the per_cpu map being accessed has
943	  been set up. This adds a fair amount of code to kernel memory
944	  and decreases performance.
945
946	  Say N if unsure.
947
948config DEBUG_KMAP_LOCAL
949	bool "Debug kmap_local temporary mappings"
950	depends on DEBUG_KERNEL && KMAP_LOCAL
951	help
952	  This option enables additional error checking for the kmap_local
953	  infrastructure.  Disable for production use.
954
955config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
956	bool
957
958config DEBUG_KMAP_LOCAL_FORCE_MAP
959	bool "Enforce kmap_local temporary mappings"
960	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
961	select KMAP_LOCAL
962	select DEBUG_KMAP_LOCAL
963	help
964	  This option enforces temporary mappings through the kmap_local
965	  mechanism for non-highmem pages and on non-highmem systems.
966	  Disable this for production systems!
967
968config DEBUG_HIGHMEM
969	bool "Highmem debugging"
970	depends on DEBUG_KERNEL && HIGHMEM
971	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
972	select DEBUG_KMAP_LOCAL
973	help
974	  This option enables additional error checking for high memory
975	  systems.  Disable for production systems.
976
977config HAVE_DEBUG_STACKOVERFLOW
978	bool
979
980config DEBUG_STACKOVERFLOW
981	bool "Check for stack overflows"
982	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
983	help
984	  Say Y here if you want to check for overflows of kernel, IRQ
985	  and exception stacks (if your architecture uses them). This
986	  option will show detailed messages if free stack space drops
987	  below a certain limit.
988
989	  These kinds of bugs usually occur when call-chains in the
990	  kernel get too deep, especially when interrupts are
991	  involved.
992
993	  Use this in cases where you see apparently random memory
994	  corruption, especially if it appears in 'struct thread_info'
995
996	  If in doubt, say "N".
997
998source "lib/Kconfig.kasan"
999source "lib/Kconfig.kfence"
1000
1001endmenu # "Memory Debugging"
1002
1003config DEBUG_SHIRQ
1004	bool "Debug shared IRQ handlers"
1005	depends on DEBUG_KERNEL
1006	help
1007	  Enable this to generate a spurious interrupt just before a shared
1008	  interrupt handler is deregistered (generating one when registering
1009	  is currently disabled). Drivers need to handle this correctly. Some
1010	  don't and need to be caught.
1011
1012menu "Debug Oops, Lockups and Hangs"
1013
1014config PANIC_ON_OOPS
1015	bool "Panic on Oops"
1016	help
1017	  Say Y here to enable the kernel to panic when it oopses. This
1018	  has the same effect as setting oops=panic on the kernel command
1019	  line.
1020
1021	  This feature is useful to ensure that the kernel does not do
1022	  anything erroneous after an oops which could result in data
1023	  corruption or other issues.
1024
1025	  Say N if unsure.
1026
1027config PANIC_ON_OOPS_VALUE
1028	int
1029	range 0 1
1030	default 0 if !PANIC_ON_OOPS
1031	default 1 if PANIC_ON_OOPS
1032
1033config PANIC_TIMEOUT
1034	int "panic timeout"
1035	default 0
1036	help
1037	  Set the timeout value (in seconds) until a reboot occurs when
1038	  the kernel panics. If n = 0, then we wait forever. A timeout
1039	  value n > 0 will wait n seconds before rebooting, while a timeout
1040	  value n < 0 will reboot immediately.
1041
1042config LOCKUP_DETECTOR
1043	bool
1044
1045config SOFTLOCKUP_DETECTOR
1046	bool "Detect Soft Lockups"
1047	depends on DEBUG_KERNEL && !S390
1048	select LOCKUP_DETECTOR
1049	help
1050	  Say Y here to enable the kernel to act as a watchdog to detect
1051	  soft lockups.
1052
1053	  Softlockups are bugs that cause the kernel to loop in kernel
1054	  mode for more than 20 seconds, without giving other tasks a
1055	  chance to run.  The current stack trace is displayed upon
1056	  detection and the system will stay locked up.
1057
1058config BOOTPARAM_SOFTLOCKUP_PANIC
1059	bool "Panic (Reboot) On Soft Lockups"
1060	depends on SOFTLOCKUP_DETECTOR
1061	help
1062	  Say Y here to enable the kernel to panic on "soft lockups",
1063	  which are bugs that cause the kernel to loop in kernel
1064	  mode for more than 20 seconds (configurable using the watchdog_thresh
1065	  sysctl), without giving other tasks a chance to run.
1066
1067	  The panic can be used in combination with panic_timeout,
1068	  to cause the system to reboot automatically after a
1069	  lockup has been detected. This feature is useful for
1070	  high-availability systems that have uptime guarantees and
1071	  where a lockup must be resolved ASAP.
1072
1073	  Say N if unsure.
1074
1075config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1076	int
1077	depends on SOFTLOCKUP_DETECTOR
1078	range 0 1
1079	default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1080	default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1081
1082config HARDLOCKUP_DETECTOR_PERF
1083	bool
1084	select SOFTLOCKUP_DETECTOR
1085
1086#
1087# Enables a timestamp based low pass filter to compensate for perf based
1088# hard lockup detection which runs too fast due to turbo modes.
1089#
1090config HARDLOCKUP_CHECK_TIMESTAMP
1091	bool
1092
1093#
1094# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1095# lockup detector rather than the perf based detector.
1096#
1097config HARDLOCKUP_DETECTOR
1098	bool "Detect Hard Lockups"
1099	depends on DEBUG_KERNEL && !S390
1100	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1101	select LOCKUP_DETECTOR
1102	select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1103	help
1104	  Say Y here to enable the kernel to act as a watchdog to detect
1105	  hard lockups.
1106
1107	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1108	  for more than 10 seconds, without letting other interrupts have a
1109	  chance to run.  The current stack trace is displayed upon detection
1110	  and the system will stay locked up.
1111
1112config BOOTPARAM_HARDLOCKUP_PANIC
1113	bool "Panic (Reboot) On Hard Lockups"
1114	depends on HARDLOCKUP_DETECTOR
1115	help
1116	  Say Y here to enable the kernel to panic on "hard lockups",
1117	  which are bugs that cause the kernel to loop in kernel
1118	  mode with interrupts disabled for more than 10 seconds (configurable
1119	  using the watchdog_thresh sysctl).
1120
1121	  Say N if unsure.
1122
1123config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1124	int
1125	depends on HARDLOCKUP_DETECTOR
1126	range 0 1
1127	default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1128	default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1129
1130config DETECT_HUNG_TASK
1131	bool "Detect Hung Tasks"
1132	depends on DEBUG_KERNEL
1133	default SOFTLOCKUP_DETECTOR
1134	help
1135	  Say Y here to enable the kernel to detect "hung tasks",
1136	  which are bugs that cause the task to be stuck in
1137	  uninterruptible "D" state indefinitely.
1138
1139	  When a hung task is detected, the kernel will print the
1140	  current stack trace (which you should report), but the
1141	  task will stay in uninterruptible state. If lockdep is
1142	  enabled then all held locks will also be reported. This
1143	  feature has negligible overhead.
1144
1145config DEFAULT_HUNG_TASK_TIMEOUT
1146	int "Default timeout for hung task detection (in seconds)"
1147	depends on DETECT_HUNG_TASK
1148	default 120
1149	help
1150	  This option controls the default timeout (in seconds) used
1151	  to determine when a task has become non-responsive and should
1152	  be considered hung.
1153
1154	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1155	  sysctl or by writing a value to
1156	  /proc/sys/kernel/hung_task_timeout_secs.
1157
1158	  A timeout of 0 disables the check.  The default is two minutes.
1159	  Keeping the default should be fine in most cases.
1160
1161config BOOTPARAM_HUNG_TASK_PANIC
1162	bool "Panic (Reboot) On Hung Tasks"
1163	depends on DETECT_HUNG_TASK
1164	help
1165	  Say Y here to enable the kernel to panic on "hung tasks",
1166	  which are bugs that cause the kernel to leave a task stuck
1167	  in uninterruptible "D" state.
1168
1169	  The panic can be used in combination with panic_timeout,
1170	  to cause the system to reboot automatically after a
1171	  hung task has been detected. This feature is useful for
1172	  high-availability systems that have uptime guarantees and
1173	  where a hung tasks must be resolved ASAP.
1174
1175	  Say N if unsure.
1176
1177config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1178	int
1179	depends on DETECT_HUNG_TASK
1180	range 0 1
1181	default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1182	default 1 if BOOTPARAM_HUNG_TASK_PANIC
1183
1184config WQ_WATCHDOG
1185	bool "Detect Workqueue Stalls"
1186	depends on DEBUG_KERNEL
1187	help
1188	  Say Y here to enable stall detection on workqueues.  If a
1189	  worker pool doesn't make forward progress on a pending work
1190	  item for over a given amount of time, 30s by default, a
1191	  warning message is printed along with dump of workqueue
1192	  state.  This can be configured through kernel parameter
1193	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1194
1195config TEST_LOCKUP
1196	tristate "Test module to generate lockups"
1197	depends on m
1198	help
1199	  This builds the "test_lockup" module that helps to make sure
1200	  that watchdogs and lockup detectors are working properly.
1201
1202	  Depending on module parameters it could emulate soft or hard
1203	  lockup, "hung task", or locking arbitrary lock for a long time.
1204	  Also it could generate series of lockups with cooling-down periods.
1205
1206	  If unsure, say N.
1207
1208endmenu # "Debug lockups and hangs"
1209
1210menu "Scheduler Debugging"
1211
1212config SCHED_DEBUG
1213	bool "Collect scheduler debugging info"
1214	depends on DEBUG_KERNEL && PROC_FS
1215	default y
1216	help
1217	  If you say Y here, the /proc/sched_debug file will be provided
1218	  that can help debug the scheduler. The runtime overhead of this
1219	  option is minimal.
1220
1221config SCHED_INFO
1222	bool
1223	default n
1224
1225config SCHEDSTATS
1226	bool "Collect scheduler statistics"
1227	depends on DEBUG_KERNEL && PROC_FS
1228	select SCHED_INFO
1229	help
1230	  If you say Y here, additional code will be inserted into the
1231	  scheduler and related routines to collect statistics about
1232	  scheduler behavior and provide them in /proc/schedstat.  These
1233	  stats may be useful for both tuning and debugging the scheduler
1234	  If you aren't debugging the scheduler or trying to tune a specific
1235	  application, you can say N to avoid the very slight overhead
1236	  this adds.
1237
1238endmenu
1239
1240config DEBUG_TIMEKEEPING
1241	bool "Enable extra timekeeping sanity checking"
1242	help
1243	  This option will enable additional timekeeping sanity checks
1244	  which may be helpful when diagnosing issues where timekeeping
1245	  problems are suspected.
1246
1247	  This may include checks in the timekeeping hotpaths, so this
1248	  option may have a (very small) performance impact to some
1249	  workloads.
1250
1251	  If unsure, say N.
1252
1253config DEBUG_PREEMPT
1254	bool "Debug preemptible kernel"
1255	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1256	default y
1257	help
1258	  If you say Y here then the kernel will use a debug variant of the
1259	  commonly used smp_processor_id() function and will print warnings
1260	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1261	  will detect preemption count underflows.
1262
1263menu "Lock Debugging (spinlocks, mutexes, etc...)"
1264
1265config LOCK_DEBUGGING_SUPPORT
1266	bool
1267	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1268	default y
1269
1270config PROVE_LOCKING
1271	bool "Lock debugging: prove locking correctness"
1272	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1273	select LOCKDEP
1274	select DEBUG_SPINLOCK
1275	select DEBUG_MUTEXES if !PREEMPT_RT
1276	select DEBUG_RT_MUTEXES if RT_MUTEXES
1277	select DEBUG_RWSEMS
1278	select DEBUG_WW_MUTEX_SLOWPATH
1279	select DEBUG_LOCK_ALLOC
1280	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1281	select TRACE_IRQFLAGS
1282	default n
1283	help
1284	 This feature enables the kernel to prove that all locking
1285	 that occurs in the kernel runtime is mathematically
1286	 correct: that under no circumstance could an arbitrary (and
1287	 not yet triggered) combination of observed locking
1288	 sequences (on an arbitrary number of CPUs, running an
1289	 arbitrary number of tasks and interrupt contexts) cause a
1290	 deadlock.
1291
1292	 In short, this feature enables the kernel to report locking
1293	 related deadlocks before they actually occur.
1294
1295	 The proof does not depend on how hard and complex a
1296	 deadlock scenario would be to trigger: how many
1297	 participant CPUs, tasks and irq-contexts would be needed
1298	 for it to trigger. The proof also does not depend on
1299	 timing: if a race and a resulting deadlock is possible
1300	 theoretically (no matter how unlikely the race scenario
1301	 is), it will be proven so and will immediately be
1302	 reported by the kernel (once the event is observed that
1303	 makes the deadlock theoretically possible).
1304
1305	 If a deadlock is impossible (i.e. the locking rules, as
1306	 observed by the kernel, are mathematically correct), the
1307	 kernel reports nothing.
1308
1309	 NOTE: this feature can also be enabled for rwlocks, mutexes
1310	 and rwsems - in which case all dependencies between these
1311	 different locking variants are observed and mapped too, and
1312	 the proof of observed correctness is also maintained for an
1313	 arbitrary combination of these separate locking variants.
1314
1315	 For more details, see Documentation/locking/lockdep-design.rst.
1316
1317config PROVE_RAW_LOCK_NESTING
1318	bool "Enable raw_spinlock - spinlock nesting checks"
1319	depends on PROVE_LOCKING
1320	default n
1321	help
1322	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1323	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1324	 not violated.
1325
1326	 NOTE: There are known nesting problems. So if you enable this
1327	 option expect lockdep splats until these problems have been fully
1328	 addressed which is work in progress. This config switch allows to
1329	 identify and analyze these problems. It will be removed and the
1330	 check permanently enabled once the main issues have been fixed.
1331
1332	 If unsure, select N.
1333
1334config LOCK_STAT
1335	bool "Lock usage statistics"
1336	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1337	select LOCKDEP
1338	select DEBUG_SPINLOCK
1339	select DEBUG_MUTEXES if !PREEMPT_RT
1340	select DEBUG_RT_MUTEXES if RT_MUTEXES
1341	select DEBUG_LOCK_ALLOC
1342	default n
1343	help
1344	 This feature enables tracking lock contention points
1345
1346	 For more details, see Documentation/locking/lockstat.rst
1347
1348	 This also enables lock events required by "perf lock",
1349	 subcommand of perf.
1350	 If you want to use "perf lock", you also need to turn on
1351	 CONFIG_EVENT_TRACING.
1352
1353	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1354	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1355
1356config DEBUG_RT_MUTEXES
1357	bool "RT Mutex debugging, deadlock detection"
1358	depends on DEBUG_KERNEL && RT_MUTEXES
1359	help
1360	 This allows rt mutex semantics violations and rt mutex related
1361	 deadlocks (lockups) to be detected and reported automatically.
1362
1363config DEBUG_SPINLOCK
1364	bool "Spinlock and rw-lock debugging: basic checks"
1365	depends on DEBUG_KERNEL
1366	select UNINLINE_SPIN_UNLOCK
1367	help
1368	  Say Y here and build SMP to catch missing spinlock initialization
1369	  and certain other kinds of spinlock errors commonly made.  This is
1370	  best used in conjunction with the NMI watchdog so that spinlock
1371	  deadlocks are also debuggable.
1372
1373config DEBUG_MUTEXES
1374	bool "Mutex debugging: basic checks"
1375	depends on DEBUG_KERNEL && !PREEMPT_RT
1376	help
1377	 This feature allows mutex semantics violations to be detected and
1378	 reported.
1379
1380config DEBUG_WW_MUTEX_SLOWPATH
1381	bool "Wait/wound mutex debugging: Slowpath testing"
1382	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1383	select DEBUG_LOCK_ALLOC
1384	select DEBUG_SPINLOCK
1385	select DEBUG_MUTEXES if !PREEMPT_RT
1386	select DEBUG_RT_MUTEXES if PREEMPT_RT
1387	help
1388	 This feature enables slowpath testing for w/w mutex users by
1389	 injecting additional -EDEADLK wound/backoff cases. Together with
1390	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1391	 will test all possible w/w mutex interface abuse with the
1392	 exception of simply not acquiring all the required locks.
1393	 Note that this feature can introduce significant overhead, so
1394	 it really should not be enabled in a production or distro kernel,
1395	 even a debug kernel.  If you are a driver writer, enable it.  If
1396	 you are a distro, do not.
1397
1398config DEBUG_RWSEMS
1399	bool "RW Semaphore debugging: basic checks"
1400	depends on DEBUG_KERNEL
1401	help
1402	  This debugging feature allows mismatched rw semaphore locks
1403	  and unlocks to be detected and reported.
1404
1405config DEBUG_LOCK_ALLOC
1406	bool "Lock debugging: detect incorrect freeing of live locks"
1407	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1408	select DEBUG_SPINLOCK
1409	select DEBUG_MUTEXES if !PREEMPT_RT
1410	select DEBUG_RT_MUTEXES if RT_MUTEXES
1411	select LOCKDEP
1412	help
1413	 This feature will check whether any held lock (spinlock, rwlock,
1414	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1415	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1416	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1417	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1418	 held during task exit.
1419
1420config LOCKDEP
1421	bool
1422	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1423	select STACKTRACE
1424	select KALLSYMS
1425	select KALLSYMS_ALL
1426
1427config LOCKDEP_SMALL
1428	bool
1429
1430config LOCKDEP_BITS
1431	int "Bitsize for MAX_LOCKDEP_ENTRIES"
1432	depends on LOCKDEP && !LOCKDEP_SMALL
1433	range 10 30
1434	default 15
1435	help
1436	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1437
1438config LOCKDEP_CHAINS_BITS
1439	int "Bitsize for MAX_LOCKDEP_CHAINS"
1440	depends on LOCKDEP && !LOCKDEP_SMALL
1441	range 10 30
1442	default 16
1443	help
1444	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1445
1446config LOCKDEP_STACK_TRACE_BITS
1447	int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1448	depends on LOCKDEP && !LOCKDEP_SMALL
1449	range 10 30
1450	default 19
1451	help
1452	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1453
1454config LOCKDEP_STACK_TRACE_HASH_BITS
1455	int "Bitsize for STACK_TRACE_HASH_SIZE"
1456	depends on LOCKDEP && !LOCKDEP_SMALL
1457	range 10 30
1458	default 14
1459	help
1460	  Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1461
1462config LOCKDEP_CIRCULAR_QUEUE_BITS
1463	int "Bitsize for elements in circular_queue struct"
1464	depends on LOCKDEP
1465	range 10 30
1466	default 12
1467	help
1468	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1469
1470config DEBUG_LOCKDEP
1471	bool "Lock dependency engine debugging"
1472	depends on DEBUG_KERNEL && LOCKDEP
1473	select DEBUG_IRQFLAGS
1474	help
1475	  If you say Y here, the lock dependency engine will do
1476	  additional runtime checks to debug itself, at the price
1477	  of more runtime overhead.
1478
1479config DEBUG_ATOMIC_SLEEP
1480	bool "Sleep inside atomic section checking"
1481	select PREEMPT_COUNT
1482	depends on DEBUG_KERNEL
1483	depends on !ARCH_NO_PREEMPT
1484	help
1485	  If you say Y here, various routines which may sleep will become very
1486	  noisy if they are called inside atomic sections: when a spinlock is
1487	  held, inside an rcu read side critical section, inside preempt disabled
1488	  sections, inside an interrupt, etc...
1489
1490config DEBUG_LOCKING_API_SELFTESTS
1491	bool "Locking API boot-time self-tests"
1492	depends on DEBUG_KERNEL
1493	help
1494	  Say Y here if you want the kernel to run a short self-test during
1495	  bootup. The self-test checks whether common types of locking bugs
1496	  are detected by debugging mechanisms or not. (if you disable
1497	  lock debugging then those bugs won't be detected of course.)
1498	  The following locking APIs are covered: spinlocks, rwlocks,
1499	  mutexes and rwsems.
1500
1501config LOCK_TORTURE_TEST
1502	tristate "torture tests for locking"
1503	depends on DEBUG_KERNEL
1504	select TORTURE_TEST
1505	help
1506	  This option provides a kernel module that runs torture tests
1507	  on kernel locking primitives.  The kernel module may be built
1508	  after the fact on the running kernel to be tested, if desired.
1509
1510	  Say Y here if you want kernel locking-primitive torture tests
1511	  to be built into the kernel.
1512	  Say M if you want these torture tests to build as a module.
1513	  Say N if you are unsure.
1514
1515config WW_MUTEX_SELFTEST
1516	tristate "Wait/wound mutex selftests"
1517	help
1518	  This option provides a kernel module that runs tests on the
1519	  on the struct ww_mutex locking API.
1520
1521	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1522	  with this test harness.
1523
1524	  Say M if you want these self tests to build as a module.
1525	  Say N if you are unsure.
1526
1527config SCF_TORTURE_TEST
1528	tristate "torture tests for smp_call_function*()"
1529	depends on DEBUG_KERNEL
1530	select TORTURE_TEST
1531	help
1532	  This option provides a kernel module that runs torture tests
1533	  on the smp_call_function() family of primitives.  The kernel
1534	  module may be built after the fact on the running kernel to
1535	  be tested, if desired.
1536
1537config CSD_LOCK_WAIT_DEBUG
1538	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1539	depends on DEBUG_KERNEL
1540	depends on 64BIT
1541	default n
1542	help
1543	  This option enables debug prints when CPUs are slow to respond
1544	  to the smp_call_function*() IPI wrappers.  These debug prints
1545	  include the IPI handler function currently executing (if any)
1546	  and relevant stack traces.
1547
1548choice
1549	prompt "Lock debugging: prove subsystem device_lock() correctness"
1550	depends on PROVE_LOCKING
1551	help
1552	  For subsystems that have instrumented their usage of the device_lock()
1553	  with nested annotations, enable lock dependency checking. The locking
1554	  hierarchy 'subclass' identifiers are not compatible across
1555	  sub-systems, so only one can be enabled at a time.
1556
1557config PROVE_NVDIMM_LOCKING
1558	bool "NVDIMM"
1559	depends on LIBNVDIMM
1560	help
1561	  Enable lockdep to validate nd_device_lock() usage.
1562
1563config PROVE_CXL_LOCKING
1564	bool "CXL"
1565	depends on CXL_BUS
1566	help
1567	  Enable lockdep to validate cxl_device_lock() usage.
1568
1569endchoice
1570
1571endmenu # lock debugging
1572
1573config TRACE_IRQFLAGS
1574	depends on TRACE_IRQFLAGS_SUPPORT
1575	bool
1576	help
1577	  Enables hooks to interrupt enabling and disabling for
1578	  either tracing or lock debugging.
1579
1580config TRACE_IRQFLAGS_NMI
1581	def_bool y
1582	depends on TRACE_IRQFLAGS
1583	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1584
1585config DEBUG_IRQFLAGS
1586	bool "Debug IRQ flag manipulation"
1587	help
1588	  Enables checks for potentially unsafe enabling or disabling of
1589	  interrupts, such as calling raw_local_irq_restore() when interrupts
1590	  are enabled.
1591
1592config STACKTRACE
1593	bool "Stack backtrace support"
1594	depends on STACKTRACE_SUPPORT
1595	help
1596	  This option causes the kernel to create a /proc/pid/stack for
1597	  every process, showing its current stack trace.
1598	  It is also used by various kernel debugging features that require
1599	  stack trace generation.
1600
1601config WARN_ALL_UNSEEDED_RANDOM
1602	bool "Warn for all uses of unseeded randomness"
1603	default n
1604	help
1605	  Some parts of the kernel contain bugs relating to their use of
1606	  cryptographically secure random numbers before it's actually possible
1607	  to generate those numbers securely. This setting ensures that these
1608	  flaws don't go unnoticed, by enabling a message, should this ever
1609	  occur. This will allow people with obscure setups to know when things
1610	  are going wrong, so that they might contact developers about fixing
1611	  it.
1612
1613	  Unfortunately, on some models of some architectures getting
1614	  a fully seeded CRNG is extremely difficult, and so this can
1615	  result in dmesg getting spammed for a surprisingly long
1616	  time.  This is really bad from a security perspective, and
1617	  so architecture maintainers really need to do what they can
1618	  to get the CRNG seeded sooner after the system is booted.
1619	  However, since users cannot do anything actionable to
1620	  address this, by default the kernel will issue only a single
1621	  warning for the first use of unseeded randomness.
1622
1623	  Say Y here if you want to receive warnings for all uses of
1624	  unseeded randomness.  This will be of use primarily for
1625	  those developers interested in improving the security of
1626	  Linux kernels running on their architecture (or
1627	  subarchitecture).
1628
1629config DEBUG_KOBJECT
1630	bool "kobject debugging"
1631	depends on DEBUG_KERNEL
1632	help
1633	  If you say Y here, some extra kobject debugging messages will be sent
1634	  to the syslog.
1635
1636config DEBUG_KOBJECT_RELEASE
1637	bool "kobject release debugging"
1638	depends on DEBUG_OBJECTS_TIMERS
1639	help
1640	  kobjects are reference counted objects.  This means that their
1641	  last reference count put is not predictable, and the kobject can
1642	  live on past the point at which a driver decides to drop it's
1643	  initial reference to the kobject gained on allocation.  An
1644	  example of this would be a struct device which has just been
1645	  unregistered.
1646
1647	  However, some buggy drivers assume that after such an operation,
1648	  the memory backing the kobject can be immediately freed.  This
1649	  goes completely against the principles of a refcounted object.
1650
1651	  If you say Y here, the kernel will delay the release of kobjects
1652	  on the last reference count to improve the visibility of this
1653	  kind of kobject release bug.
1654
1655config HAVE_DEBUG_BUGVERBOSE
1656	bool
1657
1658menu "Debug kernel data structures"
1659
1660config DEBUG_LIST
1661	bool "Debug linked list manipulation"
1662	depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1663	help
1664	  Enable this to turn on extended checks in the linked-list
1665	  walking routines.
1666
1667	  If unsure, say N.
1668
1669config DEBUG_PLIST
1670	bool "Debug priority linked list manipulation"
1671	depends on DEBUG_KERNEL
1672	help
1673	  Enable this to turn on extended checks in the priority-ordered
1674	  linked-list (plist) walking routines.  This checks the entire
1675	  list multiple times during each manipulation.
1676
1677	  If unsure, say N.
1678
1679config DEBUG_SG
1680	bool "Debug SG table operations"
1681	depends on DEBUG_KERNEL
1682	help
1683	  Enable this to turn on checks on scatter-gather tables. This can
1684	  help find problems with drivers that do not properly initialize
1685	  their sg tables.
1686
1687	  If unsure, say N.
1688
1689config DEBUG_NOTIFIERS
1690	bool "Debug notifier call chains"
1691	depends on DEBUG_KERNEL
1692	help
1693	  Enable this to turn on sanity checking for notifier call chains.
1694	  This is most useful for kernel developers to make sure that
1695	  modules properly unregister themselves from notifier chains.
1696	  This is a relatively cheap check but if you care about maximum
1697	  performance, say N.
1698
1699config BUG_ON_DATA_CORRUPTION
1700	bool "Trigger a BUG when data corruption is detected"
1701	select DEBUG_LIST
1702	help
1703	  Select this option if the kernel should BUG when it encounters
1704	  data corruption in kernel memory structures when they get checked
1705	  for validity.
1706
1707	  If unsure, say N.
1708
1709endmenu
1710
1711config DEBUG_CREDENTIALS
1712	bool "Debug credential management"
1713	depends on DEBUG_KERNEL
1714	help
1715	  Enable this to turn on some debug checking for credential
1716	  management.  The additional code keeps track of the number of
1717	  pointers from task_structs to any given cred struct, and checks to
1718	  see that this number never exceeds the usage count of the cred
1719	  struct.
1720
1721	  Furthermore, if SELinux is enabled, this also checks that the
1722	  security pointer in the cred struct is never seen to be invalid.
1723
1724	  If unsure, say N.
1725
1726source "kernel/rcu/Kconfig.debug"
1727
1728config DEBUG_WQ_FORCE_RR_CPU
1729	bool "Force round-robin CPU selection for unbound work items"
1730	depends on DEBUG_KERNEL
1731	default n
1732	help
1733	  Workqueue used to implicitly guarantee that work items queued
1734	  without explicit CPU specified are put on the local CPU.  This
1735	  guarantee is no longer true and while local CPU is still
1736	  preferred work items may be put on foreign CPUs.  Kernel
1737	  parameter "workqueue.debug_force_rr_cpu" is added to force
1738	  round-robin CPU selection to flush out usages which depend on the
1739	  now broken guarantee.  This config option enables the debug
1740	  feature by default.  When enabled, memory and cache locality will
1741	  be impacted.
1742
1743config CPU_HOTPLUG_STATE_CONTROL
1744	bool "Enable CPU hotplug state control"
1745	depends on DEBUG_KERNEL
1746	depends on HOTPLUG_CPU
1747	default n
1748	help
1749	  Allows to write steps between "offline" and "online" to the CPUs
1750	  sysfs target file so states can be stepped granular. This is a debug
1751	  option for now as the hotplug machinery cannot be stopped and
1752	  restarted at arbitrary points yet.
1753
1754	  Say N if your are unsure.
1755
1756config LATENCYTOP
1757	bool "Latency measuring infrastructure"
1758	depends on DEBUG_KERNEL
1759	depends on STACKTRACE_SUPPORT
1760	depends on PROC_FS
1761	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1762	select KALLSYMS
1763	select KALLSYMS_ALL
1764	select STACKTRACE
1765	select SCHEDSTATS
1766	help
1767	  Enable this option if you want to use the LatencyTOP tool
1768	  to find out which userspace is blocking on what kernel operations.
1769
1770source "kernel/trace/Kconfig"
1771
1772config PROVIDE_OHCI1394_DMA_INIT
1773	bool "Remote debugging over FireWire early on boot"
1774	depends on PCI && X86
1775	help
1776	  If you want to debug problems which hang or crash the kernel early
1777	  on boot and the crashing machine has a FireWire port, you can use
1778	  this feature to remotely access the memory of the crashed machine
1779	  over FireWire. This employs remote DMA as part of the OHCI1394
1780	  specification which is now the standard for FireWire controllers.
1781
1782	  With remote DMA, you can monitor the printk buffer remotely using
1783	  firescope and access all memory below 4GB using fireproxy from gdb.
1784	  Even controlling a kernel debugger is possible using remote DMA.
1785
1786	  Usage:
1787
1788	  If ohci1394_dma=early is used as boot parameter, it will initialize
1789	  all OHCI1394 controllers which are found in the PCI config space.
1790
1791	  As all changes to the FireWire bus such as enabling and disabling
1792	  devices cause a bus reset and thereby disable remote DMA for all
1793	  devices, be sure to have the cable plugged and FireWire enabled on
1794	  the debugging host before booting the debug target for debugging.
1795
1796	  This code (~1k) is freed after boot. By then, the firewire stack
1797	  in charge of the OHCI-1394 controllers should be used instead.
1798
1799	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1800
1801source "samples/Kconfig"
1802
1803config ARCH_HAS_DEVMEM_IS_ALLOWED
1804	bool
1805
1806config STRICT_DEVMEM
1807	bool "Filter access to /dev/mem"
1808	depends on MMU && DEVMEM
1809	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1810	default y if PPC || X86 || ARM64
1811	help
1812	  If this option is disabled, you allow userspace (root) access to all
1813	  of memory, including kernel and userspace memory. Accidental
1814	  access to this is obviously disastrous, but specific access can
1815	  be used by people debugging the kernel. Note that with PAT support
1816	  enabled, even in this case there are restrictions on /dev/mem
1817	  use due to the cache aliasing requirements.
1818
1819	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1820	  file only allows userspace access to PCI space and the BIOS code and
1821	  data regions.  This is sufficient for dosemu and X and all common
1822	  users of /dev/mem.
1823
1824	  If in doubt, say Y.
1825
1826config IO_STRICT_DEVMEM
1827	bool "Filter I/O access to /dev/mem"
1828	depends on STRICT_DEVMEM
1829	help
1830	  If this option is disabled, you allow userspace (root) access to all
1831	  io-memory regardless of whether a driver is actively using that
1832	  range.  Accidental access to this is obviously disastrous, but
1833	  specific access can be used by people debugging kernel drivers.
1834
1835	  If this option is switched on, the /dev/mem file only allows
1836	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1837	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1838	  if the driver using a given range cannot be disabled.
1839
1840	  If in doubt, say Y.
1841
1842menu "$(SRCARCH) Debugging"
1843
1844source "arch/$(SRCARCH)/Kconfig.debug"
1845
1846endmenu
1847
1848menu "Kernel Testing and Coverage"
1849
1850source "lib/kunit/Kconfig"
1851
1852config NOTIFIER_ERROR_INJECTION
1853	tristate "Notifier error injection"
1854	depends on DEBUG_KERNEL
1855	select DEBUG_FS
1856	help
1857	  This option provides the ability to inject artificial errors to
1858	  specified notifier chain callbacks. It is useful to test the error
1859	  handling of notifier call chain failures.
1860
1861	  Say N if unsure.
1862
1863config PM_NOTIFIER_ERROR_INJECT
1864	tristate "PM notifier error injection module"
1865	depends on PM && NOTIFIER_ERROR_INJECTION
1866	default m if PM_DEBUG
1867	help
1868	  This option provides the ability to inject artificial errors to
1869	  PM notifier chain callbacks.  It is controlled through debugfs
1870	  interface /sys/kernel/debug/notifier-error-inject/pm
1871
1872	  If the notifier call chain should be failed with some events
1873	  notified, write the error code to "actions/<notifier event>/error".
1874
1875	  Example: Inject PM suspend error (-12 = -ENOMEM)
1876
1877	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1878	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1879	  # echo mem > /sys/power/state
1880	  bash: echo: write error: Cannot allocate memory
1881
1882	  To compile this code as a module, choose M here: the module will
1883	  be called pm-notifier-error-inject.
1884
1885	  If unsure, say N.
1886
1887config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1888	tristate "OF reconfig notifier error injection module"
1889	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1890	help
1891	  This option provides the ability to inject artificial errors to
1892	  OF reconfig notifier chain callbacks.  It is controlled
1893	  through debugfs interface under
1894	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1895
1896	  If the notifier call chain should be failed with some events
1897	  notified, write the error code to "actions/<notifier event>/error".
1898
1899	  To compile this code as a module, choose M here: the module will
1900	  be called of-reconfig-notifier-error-inject.
1901
1902	  If unsure, say N.
1903
1904config NETDEV_NOTIFIER_ERROR_INJECT
1905	tristate "Netdev notifier error injection module"
1906	depends on NET && NOTIFIER_ERROR_INJECTION
1907	help
1908	  This option provides the ability to inject artificial errors to
1909	  netdevice notifier chain callbacks.  It is controlled through debugfs
1910	  interface /sys/kernel/debug/notifier-error-inject/netdev
1911
1912	  If the notifier call chain should be failed with some events
1913	  notified, write the error code to "actions/<notifier event>/error".
1914
1915	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
1916
1917	  # cd /sys/kernel/debug/notifier-error-inject/netdev
1918	  # echo -22 > actions/NETDEV_CHANGEMTU/error
1919	  # ip link set eth0 mtu 1024
1920	  RTNETLINK answers: Invalid argument
1921
1922	  To compile this code as a module, choose M here: the module will
1923	  be called netdev-notifier-error-inject.
1924
1925	  If unsure, say N.
1926
1927config FUNCTION_ERROR_INJECTION
1928	def_bool y
1929	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1930
1931config FAULT_INJECTION
1932	bool "Fault-injection framework"
1933	depends on DEBUG_KERNEL
1934	help
1935	  Provide fault-injection framework.
1936	  For more details, see Documentation/fault-injection/.
1937
1938config FAILSLAB
1939	bool "Fault-injection capability for kmalloc"
1940	depends on FAULT_INJECTION
1941	depends on SLAB || SLUB
1942	help
1943	  Provide fault-injection capability for kmalloc.
1944
1945config FAIL_PAGE_ALLOC
1946	bool "Fault-injection capability for alloc_pages()"
1947	depends on FAULT_INJECTION
1948	help
1949	  Provide fault-injection capability for alloc_pages().
1950
1951config FAULT_INJECTION_USERCOPY
1952	bool "Fault injection capability for usercopy functions"
1953	depends on FAULT_INJECTION
1954	help
1955	  Provides fault-injection capability to inject failures
1956	  in usercopy functions (copy_from_user(), get_user(), ...).
1957
1958config FAIL_MAKE_REQUEST
1959	bool "Fault-injection capability for disk IO"
1960	depends on FAULT_INJECTION && BLOCK
1961	help
1962	  Provide fault-injection capability for disk IO.
1963
1964config FAIL_IO_TIMEOUT
1965	bool "Fault-injection capability for faking disk interrupts"
1966	depends on FAULT_INJECTION && BLOCK
1967	help
1968	  Provide fault-injection capability on end IO handling. This
1969	  will make the block layer "forget" an interrupt as configured,
1970	  thus exercising the error handling.
1971
1972	  Only works with drivers that use the generic timeout handling,
1973	  for others it won't do anything.
1974
1975config FAIL_FUTEX
1976	bool "Fault-injection capability for futexes"
1977	select DEBUG_FS
1978	depends on FAULT_INJECTION && FUTEX
1979	help
1980	  Provide fault-injection capability for futexes.
1981
1982config FAULT_INJECTION_DEBUG_FS
1983	bool "Debugfs entries for fault-injection capabilities"
1984	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1985	help
1986	  Enable configuration of fault-injection capabilities via debugfs.
1987
1988config FAIL_FUNCTION
1989	bool "Fault-injection capability for functions"
1990	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1991	help
1992	  Provide function-based fault-injection capability.
1993	  This will allow you to override a specific function with a return
1994	  with given return value. As a result, function caller will see
1995	  an error value and have to handle it. This is useful to test the
1996	  error handling in various subsystems.
1997
1998config FAIL_MMC_REQUEST
1999	bool "Fault-injection capability for MMC IO"
2000	depends on FAULT_INJECTION_DEBUG_FS && MMC
2001	help
2002	  Provide fault-injection capability for MMC IO.
2003	  This will make the mmc core return data errors. This is
2004	  useful to test the error handling in the mmc block device
2005	  and to test how the mmc host driver handles retries from
2006	  the block device.
2007
2008config FAIL_SUNRPC
2009	bool "Fault-injection capability for SunRPC"
2010	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2011	help
2012	  Provide fault-injection capability for SunRPC and
2013	  its consumers.
2014
2015config FAULT_INJECTION_STACKTRACE_FILTER
2016	bool "stacktrace filter for fault-injection capabilities"
2017	depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2018	depends on !X86_64
2019	select STACKTRACE
2020	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2021	help
2022	  Provide stacktrace filter for fault-injection capabilities
2023
2024config ARCH_HAS_KCOV
2025	bool
2026	help
2027	  An architecture should select this when it can successfully
2028	  build and run with CONFIG_KCOV. This typically requires
2029	  disabling instrumentation for some early boot code.
2030
2031config CC_HAS_SANCOV_TRACE_PC
2032	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2033
2034
2035config KCOV
2036	bool "Code coverage for fuzzing"
2037	depends on ARCH_HAS_KCOV
2038	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2039	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2040		   GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2041	select DEBUG_FS
2042	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2043	select OBJTOOL if HAVE_NOINSTR_HACK
2044	help
2045	  KCOV exposes kernel code coverage information in a form suitable
2046	  for coverage-guided fuzzing (randomized testing).
2047
2048	  If RANDOMIZE_BASE is enabled, PC values will not be stable across
2049	  different machines and across reboots. If you need stable PC values,
2050	  disable RANDOMIZE_BASE.
2051
2052	  For more details, see Documentation/dev-tools/kcov.rst.
2053
2054config KCOV_ENABLE_COMPARISONS
2055	bool "Enable comparison operands collection by KCOV"
2056	depends on KCOV
2057	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2058	help
2059	  KCOV also exposes operands of every comparison in the instrumented
2060	  code along with operand sizes and PCs of the comparison instructions.
2061	  These operands can be used by fuzzing engines to improve the quality
2062	  of fuzzing coverage.
2063
2064config KCOV_INSTRUMENT_ALL
2065	bool "Instrument all code by default"
2066	depends on KCOV
2067	default y
2068	help
2069	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2070	  then you will want to instrument the whole kernel and you should
2071	  say y here. If you are doing more targeted fuzzing (like e.g.
2072	  filesystem fuzzing with AFL) then you will want to enable coverage
2073	  for more specific subsets of files, and should say n here.
2074
2075config KCOV_IRQ_AREA_SIZE
2076	hex "Size of interrupt coverage collection area in words"
2077	depends on KCOV
2078	default 0x40000
2079	help
2080	  KCOV uses preallocated per-cpu areas to collect coverage from
2081	  soft interrupts. This specifies the size of those areas in the
2082	  number of unsigned long words.
2083
2084menuconfig RUNTIME_TESTING_MENU
2085	bool "Runtime Testing"
2086	def_bool y
2087
2088if RUNTIME_TESTING_MENU
2089
2090config LKDTM
2091	tristate "Linux Kernel Dump Test Tool Module"
2092	depends on DEBUG_FS
2093	help
2094	This module enables testing of the different dumping mechanisms by
2095	inducing system failures at predefined crash points.
2096	If you don't need it: say N
2097	Choose M here to compile this code as a module. The module will be
2098	called lkdtm.
2099
2100	Documentation on how to use the module can be found in
2101	Documentation/fault-injection/provoke-crashes.rst
2102
2103config TEST_LIST_SORT
2104	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2105	depends on KUNIT
2106	default KUNIT_ALL_TESTS
2107	help
2108	  Enable this to turn on 'list_sort()' function test. This test is
2109	  executed only once during system boot (so affects only boot time),
2110	  or at module load time.
2111
2112	  If unsure, say N.
2113
2114config TEST_MIN_HEAP
2115	tristate "Min heap test"
2116	depends on DEBUG_KERNEL || m
2117	help
2118	  Enable this to turn on min heap function tests. This test is
2119	  executed only once during system boot (so affects only boot time),
2120	  or at module load time.
2121
2122	  If unsure, say N.
2123
2124config TEST_SORT
2125	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2126	depends on KUNIT
2127	default KUNIT_ALL_TESTS
2128	help
2129	  This option enables the self-test function of 'sort()' at boot,
2130	  or at module load time.
2131
2132	  If unsure, say N.
2133
2134config TEST_DIV64
2135	tristate "64bit/32bit division and modulo test"
2136	depends on DEBUG_KERNEL || m
2137	help
2138	  Enable this to turn on 'do_div()' function test. This test is
2139	  executed only once during system boot (so affects only boot time),
2140	  or at module load time.
2141
2142	  If unsure, say N.
2143
2144config KPROBES_SANITY_TEST
2145	tristate "Kprobes sanity tests"
2146	depends on DEBUG_KERNEL
2147	depends on KPROBES
2148	depends on KUNIT
2149	help
2150	  This option provides for testing basic kprobes functionality on
2151	  boot. Samples of kprobe and kretprobe are inserted and
2152	  verified for functionality.
2153
2154	  Say N if you are unsure.
2155
2156config FPROBE_SANITY_TEST
2157	bool "Self test for fprobe"
2158	depends on DEBUG_KERNEL
2159	depends on FPROBE
2160	depends on KUNIT=y
2161	help
2162	  This option will enable testing the fprobe when the system boot.
2163	  A series of tests are made to verify that the fprobe is functioning
2164	  properly.
2165
2166	  Say N if you are unsure.
2167
2168config BACKTRACE_SELF_TEST
2169	tristate "Self test for the backtrace code"
2170	depends on DEBUG_KERNEL
2171	help
2172	  This option provides a kernel module that can be used to test
2173	  the kernel stack backtrace code. This option is not useful
2174	  for distributions or general kernels, but only for kernel
2175	  developers working on architecture code.
2176
2177	  Note that if you want to also test saved backtraces, you will
2178	  have to enable STACKTRACE as well.
2179
2180	  Say N if you are unsure.
2181
2182config TEST_REF_TRACKER
2183	tristate "Self test for reference tracker"
2184	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2185	select REF_TRACKER
2186	help
2187	  This option provides a kernel module performing tests
2188	  using reference tracker infrastructure.
2189
2190	  Say N if you are unsure.
2191
2192config RBTREE_TEST
2193	tristate "Red-Black tree test"
2194	depends on DEBUG_KERNEL
2195	help
2196	  A benchmark measuring the performance of the rbtree library.
2197	  Also includes rbtree invariant checks.
2198
2199config REED_SOLOMON_TEST
2200	tristate "Reed-Solomon library test"
2201	depends on DEBUG_KERNEL || m
2202	select REED_SOLOMON
2203	select REED_SOLOMON_ENC16
2204	select REED_SOLOMON_DEC16
2205	help
2206	  This option enables the self-test function of rslib at boot,
2207	  or at module load time.
2208
2209	  If unsure, say N.
2210
2211config INTERVAL_TREE_TEST
2212	tristate "Interval tree test"
2213	depends on DEBUG_KERNEL
2214	select INTERVAL_TREE
2215	help
2216	  A benchmark measuring the performance of the interval tree library
2217
2218config PERCPU_TEST
2219	tristate "Per cpu operations test"
2220	depends on m && DEBUG_KERNEL
2221	help
2222	  Enable this option to build test module which validates per-cpu
2223	  operations.
2224
2225	  If unsure, say N.
2226
2227config ATOMIC64_SELFTEST
2228	tristate "Perform an atomic64_t self-test"
2229	help
2230	  Enable this option to test the atomic64_t functions at boot or
2231	  at module load time.
2232
2233	  If unsure, say N.
2234
2235config ASYNC_RAID6_TEST
2236	tristate "Self test for hardware accelerated raid6 recovery"
2237	depends on ASYNC_RAID6_RECOV
2238	select ASYNC_MEMCPY
2239	help
2240	  This is a one-shot self test that permutes through the
2241	  recovery of all the possible two disk failure scenarios for a
2242	  N-disk array.  Recovery is performed with the asynchronous
2243	  raid6 recovery routines, and will optionally use an offload
2244	  engine if one is available.
2245
2246	  If unsure, say N.
2247
2248config TEST_HEXDUMP
2249	tristate "Test functions located in the hexdump module at runtime"
2250
2251config STRING_SELFTEST
2252	tristate "Test string functions at runtime"
2253
2254config TEST_STRING_HELPERS
2255	tristate "Test functions located in the string_helpers module at runtime"
2256
2257config TEST_STRSCPY
2258	tristate "Test strscpy*() family of functions at runtime"
2259
2260config TEST_KSTRTOX
2261	tristate "Test kstrto*() family of functions at runtime"
2262
2263config TEST_PRINTF
2264	tristate "Test printf() family of functions at runtime"
2265
2266config TEST_SCANF
2267	tristate "Test scanf() family of functions at runtime"
2268
2269config TEST_BITMAP
2270	tristate "Test bitmap_*() family of functions at runtime"
2271	help
2272	  Enable this option to test the bitmap functions at boot.
2273
2274	  If unsure, say N.
2275
2276config TEST_UUID
2277	tristate "Test functions located in the uuid module at runtime"
2278
2279config TEST_XARRAY
2280	tristate "Test the XArray code at runtime"
2281
2282config TEST_RHASHTABLE
2283	tristate "Perform selftest on resizable hash table"
2284	help
2285	  Enable this option to test the rhashtable functions at boot.
2286
2287	  If unsure, say N.
2288
2289config TEST_SIPHASH
2290	tristate "Perform selftest on siphash functions"
2291	help
2292	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2293	  functions on boot (or module load).
2294
2295	  This is intended to help people writing architecture-specific
2296	  optimized versions.  If unsure, say N.
2297
2298config TEST_IDA
2299	tristate "Perform selftest on IDA functions"
2300
2301config TEST_PARMAN
2302	tristate "Perform selftest on priority array manager"
2303	depends on PARMAN
2304	help
2305	  Enable this option to test priority array manager on boot
2306	  (or module load).
2307
2308	  If unsure, say N.
2309
2310config TEST_IRQ_TIMINGS
2311	bool "IRQ timings selftest"
2312	depends on IRQ_TIMINGS
2313	help
2314	  Enable this option to test the irq timings code on boot.
2315
2316	  If unsure, say N.
2317
2318config TEST_LKM
2319	tristate "Test module loading with 'hello world' module"
2320	depends on m
2321	help
2322	  This builds the "test_module" module that emits "Hello, world"
2323	  on printk when loaded. It is designed to be used for basic
2324	  evaluation of the module loading subsystem (for example when
2325	  validating module verification). It lacks any extra dependencies,
2326	  and will not normally be loaded by the system unless explicitly
2327	  requested by name.
2328
2329	  If unsure, say N.
2330
2331config TEST_BITOPS
2332	tristate "Test module for compilation of bitops operations"
2333	depends on m
2334	help
2335	  This builds the "test_bitops" module that is much like the
2336	  TEST_LKM module except that it does a basic exercise of the
2337	  set/clear_bit macros and get_count_order/long to make sure there are
2338	  no compiler warnings from C=1 sparse checker or -Wextra
2339	  compilations. It has no dependencies and doesn't run or load unless
2340	  explicitly requested by name.  for example: modprobe test_bitops.
2341
2342	  If unsure, say N.
2343
2344config TEST_VMALLOC
2345	tristate "Test module for stress/performance analysis of vmalloc allocator"
2346	default n
2347       depends on MMU
2348	depends on m
2349	help
2350	  This builds the "test_vmalloc" module that should be used for
2351	  stress and performance analysis. So, any new change for vmalloc
2352	  subsystem can be evaluated from performance and stability point
2353	  of view.
2354
2355	  If unsure, say N.
2356
2357config TEST_USER_COPY
2358	tristate "Test user/kernel boundary protections"
2359	depends on m
2360	help
2361	  This builds the "test_user_copy" module that runs sanity checks
2362	  on the copy_to/from_user infrastructure, making sure basic
2363	  user/kernel boundary testing is working. If it fails to load,
2364	  a regression has been detected in the user/kernel memory boundary
2365	  protections.
2366
2367	  If unsure, say N.
2368
2369config TEST_BPF
2370	tristate "Test BPF filter functionality"
2371	depends on m && NET
2372	help
2373	  This builds the "test_bpf" module that runs various test vectors
2374	  against the BPF interpreter or BPF JIT compiler depending on the
2375	  current setting. This is in particular useful for BPF JIT compiler
2376	  development, but also to run regression tests against changes in
2377	  the interpreter code. It also enables test stubs for eBPF maps and
2378	  verifier used by user space verifier testsuite.
2379
2380	  If unsure, say N.
2381
2382config TEST_BLACKHOLE_DEV
2383	tristate "Test blackhole netdev functionality"
2384	depends on m && NET
2385	help
2386	  This builds the "test_blackhole_dev" module that validates the
2387	  data path through this blackhole netdev.
2388
2389	  If unsure, say N.
2390
2391config FIND_BIT_BENCHMARK
2392	tristate "Test find_bit functions"
2393	help
2394	  This builds the "test_find_bit" module that measure find_*_bit()
2395	  functions performance.
2396
2397	  If unsure, say N.
2398
2399config TEST_FIRMWARE
2400	tristate "Test firmware loading via userspace interface"
2401	depends on FW_LOADER
2402	help
2403	  This builds the "test_firmware" module that creates a userspace
2404	  interface for testing firmware loading. This can be used to
2405	  control the triggering of firmware loading without needing an
2406	  actual firmware-using device. The contents can be rechecked by
2407	  userspace.
2408
2409	  If unsure, say N.
2410
2411config TEST_SYSCTL
2412	tristate "sysctl test driver"
2413	depends on PROC_SYSCTL
2414	help
2415	  This builds the "test_sysctl" module. This driver enables to test the
2416	  proc sysctl interfaces available to drivers safely without affecting
2417	  production knobs which might alter system functionality.
2418
2419	  If unsure, say N.
2420
2421config BITFIELD_KUNIT
2422	tristate "KUnit test bitfield functions at runtime"
2423	depends on KUNIT
2424	help
2425	  Enable this option to test the bitfield functions at boot.
2426
2427	  KUnit tests run during boot and output the results to the debug log
2428	  in TAP format (http://testanything.org/). Only useful for kernel devs
2429	  running the KUnit test harness, and not intended for inclusion into a
2430	  production build.
2431
2432	  For more information on KUnit and unit tests in general please refer
2433	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2434
2435	  If unsure, say N.
2436
2437config HASH_KUNIT_TEST
2438	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2439	depends on KUNIT
2440	default KUNIT_ALL_TESTS
2441	help
2442	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2443	  integer (<linux/hash.h>) hash functions on boot.
2444
2445	  KUnit tests run during boot and output the results to the debug log
2446	  in TAP format (https://testanything.org/). Only useful for kernel devs
2447	  running the KUnit test harness, and not intended for inclusion into a
2448	  production build.
2449
2450	  For more information on KUnit and unit tests in general please refer
2451	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2452
2453	  This is intended to help people writing architecture-specific
2454	  optimized versions. If unsure, say N.
2455
2456config RESOURCE_KUNIT_TEST
2457	tristate "KUnit test for resource API"
2458	depends on KUNIT
2459	help
2460	  This builds the resource API unit test.
2461	  Tests the logic of API provided by resource.c and ioport.h.
2462	  For more information on KUnit and unit tests in general please refer
2463	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2464
2465	  If unsure, say N.
2466
2467config SYSCTL_KUNIT_TEST
2468	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2469	depends on KUNIT
2470	default KUNIT_ALL_TESTS
2471	help
2472	  This builds the proc sysctl unit test, which runs on boot.
2473	  Tests the API contract and implementation correctness of sysctl.
2474	  For more information on KUnit and unit tests in general please refer
2475	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2476
2477	  If unsure, say N.
2478
2479config LIST_KUNIT_TEST
2480	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2481	depends on KUNIT
2482	default KUNIT_ALL_TESTS
2483	help
2484	  This builds the linked list KUnit test suite.
2485	  It tests that the API and basic functionality of the list_head type
2486	  and associated macros.
2487
2488	  KUnit tests run during boot and output the results to the debug log
2489	  in TAP format (https://testanything.org/). Only useful for kernel devs
2490	  running the KUnit test harness, and not intended for inclusion into a
2491	  production build.
2492
2493	  For more information on KUnit and unit tests in general please refer
2494	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2495
2496	  If unsure, say N.
2497
2498config LINEAR_RANGES_TEST
2499	tristate "KUnit test for linear_ranges"
2500	depends on KUNIT
2501	select LINEAR_RANGES
2502	help
2503	  This builds the linear_ranges unit test, which runs on boot.
2504	  Tests the linear_ranges logic correctness.
2505	  For more information on KUnit and unit tests in general please refer
2506	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2507
2508	  If unsure, say N.
2509
2510config CMDLINE_KUNIT_TEST
2511	tristate "KUnit test for cmdline API"
2512	depends on KUNIT
2513	help
2514	  This builds the cmdline API unit test.
2515	  Tests the logic of API provided by cmdline.c.
2516	  For more information on KUnit and unit tests in general please refer
2517	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2518
2519	  If unsure, say N.
2520
2521config BITS_TEST
2522	tristate "KUnit test for bits.h"
2523	depends on KUNIT
2524	help
2525	  This builds the bits unit test.
2526	  Tests the logic of macros defined in bits.h.
2527	  For more information on KUnit and unit tests in general please refer
2528	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2529
2530	  If unsure, say N.
2531
2532config SLUB_KUNIT_TEST
2533	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2534	depends on SLUB_DEBUG && KUNIT
2535	default KUNIT_ALL_TESTS
2536	help
2537	  This builds SLUB allocator unit test.
2538	  Tests SLUB cache debugging functionality.
2539	  For more information on KUnit and unit tests in general please refer
2540	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2541
2542	  If unsure, say N.
2543
2544config RATIONAL_KUNIT_TEST
2545	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2546	depends on KUNIT && RATIONAL
2547	default KUNIT_ALL_TESTS
2548	help
2549	  This builds the rational math unit test.
2550	  For more information on KUnit and unit tests in general please refer
2551	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2552
2553	  If unsure, say N.
2554
2555config MEMCPY_KUNIT_TEST
2556	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2557	depends on KUNIT
2558	default KUNIT_ALL_TESTS
2559	help
2560	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2561	  For more information on KUnit and unit tests in general please refer
2562	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2563
2564	  If unsure, say N.
2565
2566config OVERFLOW_KUNIT_TEST
2567	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2568	depends on KUNIT
2569	default KUNIT_ALL_TESTS
2570	help
2571	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2572	  related functions.
2573
2574	  For more information on KUnit and unit tests in general please refer
2575	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2576
2577	  If unsure, say N.
2578
2579config STACKINIT_KUNIT_TEST
2580	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2581	depends on KUNIT
2582	default KUNIT_ALL_TESTS
2583	help
2584	  Test if the kernel is zero-initializing stack variables and
2585	  padding. Coverage is controlled by compiler flags,
2586	  CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2587	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2588	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2589
2590config TEST_UDELAY
2591	tristate "udelay test driver"
2592	help
2593	  This builds the "udelay_test" module that helps to make sure
2594	  that udelay() is working properly.
2595
2596	  If unsure, say N.
2597
2598config TEST_STATIC_KEYS
2599	tristate "Test static keys"
2600	depends on m
2601	help
2602	  Test the static key interfaces.
2603
2604	  If unsure, say N.
2605
2606config TEST_KMOD
2607	tristate "kmod stress tester"
2608	depends on m
2609	depends on NETDEVICES && NET_CORE && INET # for TUN
2610	depends on BLOCK
2611	depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2612	select TEST_LKM
2613	select XFS_FS
2614	select TUN
2615	select BTRFS_FS
2616	help
2617	  Test the kernel's module loading mechanism: kmod. kmod implements
2618	  support to load modules using the Linux kernel's usermode helper.
2619	  This test provides a series of tests against kmod.
2620
2621	  Although technically you can either build test_kmod as a module or
2622	  into the kernel we disallow building it into the kernel since
2623	  it stress tests request_module() and this will very likely cause
2624	  some issues by taking over precious threads available from other
2625	  module load requests, ultimately this could be fatal.
2626
2627	  To run tests run:
2628
2629	  tools/testing/selftests/kmod/kmod.sh --help
2630
2631	  If unsure, say N.
2632
2633config TEST_DEBUG_VIRTUAL
2634	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2635	depends on DEBUG_VIRTUAL
2636	help
2637	  Test the kernel's ability to detect incorrect calls to
2638	  virt_to_phys() done against the non-linear part of the
2639	  kernel's virtual address map.
2640
2641	  If unsure, say N.
2642
2643config TEST_MEMCAT_P
2644	tristate "Test memcat_p() helper function"
2645	help
2646	  Test the memcat_p() helper for correctly merging two
2647	  pointer arrays together.
2648
2649	  If unsure, say N.
2650
2651config TEST_LIVEPATCH
2652	tristate "Test livepatching"
2653	default n
2654	depends on DYNAMIC_DEBUG
2655	depends on LIVEPATCH
2656	depends on m
2657	help
2658	  Test kernel livepatching features for correctness.  The tests will
2659	  load test modules that will be livepatched in various scenarios.
2660
2661	  To run all the livepatching tests:
2662
2663	  make -C tools/testing/selftests TARGETS=livepatch run_tests
2664
2665	  Alternatively, individual tests may be invoked:
2666
2667	  tools/testing/selftests/livepatch/test-callbacks.sh
2668	  tools/testing/selftests/livepatch/test-livepatch.sh
2669	  tools/testing/selftests/livepatch/test-shadow-vars.sh
2670
2671	  If unsure, say N.
2672
2673config TEST_OBJAGG
2674	tristate "Perform selftest on object aggreration manager"
2675	default n
2676	depends on OBJAGG
2677	help
2678	  Enable this option to test object aggregation manager on boot
2679	  (or module load).
2680
2681config TEST_MEMINIT
2682	tristate "Test heap/page initialization"
2683	help
2684	  Test if the kernel is zero-initializing heap and page allocations.
2685	  This can be useful to test init_on_alloc and init_on_free features.
2686
2687	  If unsure, say N.
2688
2689config TEST_HMM
2690	tristate "Test HMM (Heterogeneous Memory Management)"
2691	depends on TRANSPARENT_HUGEPAGE
2692	depends on DEVICE_PRIVATE
2693	select HMM_MIRROR
2694	select MMU_NOTIFIER
2695	help
2696	  This is a pseudo device driver solely for testing HMM.
2697	  Say M here if you want to build the HMM test module.
2698	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2699
2700	  If unsure, say N.
2701
2702config TEST_FREE_PAGES
2703	tristate "Test freeing pages"
2704	help
2705	  Test that a memory leak does not occur due to a race between
2706	  freeing a block of pages and a speculative page reference.
2707	  Loading this module is safe if your kernel has the bug fixed.
2708	  If the bug is not fixed, it will leak gigabytes of memory and
2709	  probably OOM your system.
2710
2711config TEST_FPU
2712	tristate "Test floating point operations in kernel space"
2713	depends on X86 && !KCOV_INSTRUMENT_ALL
2714	help
2715	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2716	  which will trigger a sequence of floating point operations. This is used
2717	  for self-testing floating point control register setting in
2718	  kernel_fpu_begin().
2719
2720	  If unsure, say N.
2721
2722config TEST_CLOCKSOURCE_WATCHDOG
2723	tristate "Test clocksource watchdog in kernel space"
2724	depends on CLOCKSOURCE_WATCHDOG
2725	help
2726	  Enable this option to create a kernel module that will trigger
2727	  a test of the clocksource watchdog.  This module may be loaded
2728	  via modprobe or insmod in which case it will run upon being
2729	  loaded, or it may be built in, in which case it will run
2730	  shortly after boot.
2731
2732	  If unsure, say N.
2733
2734endif # RUNTIME_TESTING_MENU
2735
2736config ARCH_USE_MEMTEST
2737	bool
2738	help
2739	  An architecture should select this when it uses early_memtest()
2740	  during boot process.
2741
2742config MEMTEST
2743	bool "Memtest"
2744	depends on ARCH_USE_MEMTEST
2745	help
2746	  This option adds a kernel parameter 'memtest', which allows memtest
2747	  to be set and executed.
2748	        memtest=0, mean disabled; -- default
2749	        memtest=1, mean do 1 test pattern;
2750	        ...
2751	        memtest=17, mean do 17 test patterns.
2752	  If you are unsure how to answer this question, answer N.
2753
2754
2755
2756config HYPERV_TESTING
2757	bool "Microsoft Hyper-V driver testing"
2758	default n
2759	depends on HYPERV && DEBUG_FS
2760	help
2761	  Select this option to enable Hyper-V vmbus testing.
2762
2763endmenu # "Kernel Testing and Coverage"
2764
2765source "Documentation/Kconfig"
2766
2767endmenu # Kernel hacking
2768