xref: /linux/lib/Kconfig.debug (revision f144367d012929326f15a399394a9a8be4f98acb)
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 jiffy" 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
209config DEBUG_BUGVERBOSE_DETAILED
210	bool "Verbose WARN_ON_ONCE() reporting (adds 100K)" if DEBUG_BUGVERBOSE
211	help
212	  Say Y here to make WARN_ON_ONCE() output the condition string of the
213	  warning, in addition to the file name and line number.
214	  This helps debugging, but costs about 100K of memory.
215
216	  Say N if unsure.
217
218
219endmenu # "printk and dmesg options"
220
221config DEBUG_KERNEL
222	bool "Kernel debugging"
223	help
224	  Say Y here if you are developing drivers or trying to debug and
225	  identify kernel problems.
226
227config DEBUG_MISC
228	bool "Miscellaneous debug code"
229	default DEBUG_KERNEL
230	depends on DEBUG_KERNEL
231	help
232	  Say Y here if you need to enable miscellaneous debug code that should
233	  be under a more specific debug option but isn't.
234
235menu "Compile-time checks and compiler options"
236
237config DEBUG_INFO
238	bool
239	help
240	  A kernel debug info option other than "None" has been selected
241	  in the "Debug information" choice below, indicating that debug
242	  information will be generated for build targets.
243
244# Clang generates .uleb128 with label differences for DWARF v5, a feature that
245# older binutils ports do not support when utilizing RISC-V style linker
246# relaxation: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
247config AS_HAS_NON_CONST_ULEB128
248	def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
249
250choice
251	prompt "Debug information"
252	depends on DEBUG_KERNEL
253	help
254	  Selecting something other than "None" results in a kernel image
255	  that will include debugging info resulting in a larger kernel image.
256	  This adds debug symbols to the kernel and modules (gcc -g), and
257	  is needed if you intend to use kernel crashdump or binary object
258	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
259
260	  Choose which version of DWARF debug info to emit. If unsure,
261	  select "Toolchain default".
262
263config DEBUG_INFO_NONE
264	bool "Disable debug information"
265	help
266	  Do not build the kernel with debugging information, which will
267	  result in a faster and smaller build.
268
269config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
270	bool "Rely on the toolchain's implicit default DWARF version"
271	select DEBUG_INFO
272	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
273	help
274	  The implicit default version of DWARF debug info produced by a
275	  toolchain changes over time.
276
277	  This can break consumers of the debug info that haven't upgraded to
278	  support newer revisions, and prevent testing newer versions, but
279	  those should be less common scenarios.
280
281config DEBUG_INFO_DWARF4
282	bool "Generate DWARF Version 4 debuginfo"
283	select DEBUG_INFO
284	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
285	help
286	  Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
287	  if using clang without clang's integrated assembler, and gdb 7.0+.
288
289	  If you have consumers of DWARF debug info that are not ready for
290	  newer revisions of DWARF, you may wish to choose this or have your
291	  config select this.
292
293config DEBUG_INFO_DWARF5
294	bool "Generate DWARF Version 5 debuginfo"
295	select DEBUG_INFO
296	depends on !ARCH_HAS_BROKEN_DWARF5
297	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
298	help
299	  Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
300	  5.0+ accepts the -gdwarf-5 flag but only had partial support for some
301	  draft features until 7.0), and gdb 8.0+.
302
303	  Changes to the structure of debug info in Version 5 allow for around
304	  15-18% savings in resulting image and debug info section sizes as
305	  compared to DWARF Version 4. DWARF Version 5 standardizes previous
306	  extensions such as accelerators for symbol indexing and the format
307	  for fission (.dwo/.dwp) files. Users may not want to select this
308	  config if they rely on tooling that has not yet been updated to
309	  support DWARF Version 5.
310
311endchoice # "Debug information"
312
313if DEBUG_INFO
314
315config DEBUG_INFO_REDUCED
316	bool "Reduce debugging information"
317	help
318	  If you say Y here gcc is instructed to generate less debugging
319	  information for structure types. This means that tools that
320	  need full debugging information (like kgdb or systemtap) won't
321	  be happy. But if you merely need debugging information to
322	  resolve line numbers there is no loss. Advantage is that
323	  build directory object sizes shrink dramatically over a full
324	  DEBUG_INFO build and compile times are reduced too.
325	  Only works with newer gcc versions.
326
327choice
328	prompt "Compressed Debug information"
329	help
330	  Compress the resulting debug info. Results in smaller debug info sections,
331	  but requires that consumers are able to decompress the results.
332
333	  If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
334
335config DEBUG_INFO_COMPRESSED_NONE
336	bool "Don't compress debug information"
337	help
338	  Don't compress debug info sections.
339
340config DEBUG_INFO_COMPRESSED_ZLIB
341	bool "Compress debugging information with zlib"
342	depends on $(cc-option,-gz=zlib)
343	depends on $(ld-option,--compress-debug-sections=zlib)
344	help
345	  Compress the debug information using zlib.
346
347	  Users of dpkg-deb via debian/rules may find an increase in
348	  size of their debug .deb packages with this config set, due to the
349	  debug info being compressed with zlib, then the object files being
350	  recompressed with a different compression scheme. But this is still
351	  preferable to setting KDEB_COMPRESS or DPKG_DEB_COMPRESSOR_TYPE to
352	  "none" which would be even larger.
353
354config DEBUG_INFO_COMPRESSED_ZSTD
355	bool "Compress debugging information with zstd"
356	depends on $(cc-option,-gz=zstd)
357	depends on $(ld-option,--compress-debug-sections=zstd)
358	help
359	  Compress the debug information using zstd.  This may provide better
360	  compression than zlib, for about the same time costs, but requires newer
361	  toolchain support.  Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
362	  zstd.
363
364endchoice # "Compressed Debug information"
365
366config DEBUG_INFO_SPLIT
367	bool "Produce split debuginfo in .dwo files"
368	depends on $(cc-option,-gsplit-dwarf)
369	# RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC
370	# prior to 12.x:
371	# https://github.com/llvm/llvm-project/issues/56642
372	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090
373	depends on !RISCV || GCC_VERSION >= 120000
374	help
375	  Generate debug info into separate .dwo files. This significantly
376	  reduces the build directory size for builds with DEBUG_INFO,
377	  because it stores the information only once on disk in .dwo
378	  files instead of multiple times in object files and executables.
379	  In addition the debug information is also compressed.
380
381	  Requires recent gcc (4.7+) and recent gdb/binutils.
382	  Any tool that packages or reads debug information would need
383	  to know about the .dwo files and include them.
384	  Incompatible with older versions of ccache.
385
386config DEBUG_INFO_BTF
387	bool "Generate BTF type information"
388	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
389	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
390	depends on BPF_SYSCALL
391	depends on PAHOLE_VERSION >= 122
392	# pahole uses elfutils, which does not have support for Hexagon relocations
393	depends on !HEXAGON
394	help
395	  Generate deduplicated BTF type information from DWARF debug info.
396	  Turning this on requires pahole v1.22 or later, which will convert
397	  DWARF type info into equivalent deduplicated BTF type info.
398
399config PAHOLE_HAS_BTF_TAG
400	def_bool PAHOLE_VERSION >= 123
401	depends on CC_IS_CLANG
402	help
403	  Decide whether pahole emits btf_tag attributes (btf_type_tag and
404	  btf_decl_tag) or not. Currently only clang compiler implements
405	  these attributes, so make the config depend on CC_IS_CLANG.
406
407config PAHOLE_HAS_LANG_EXCLUDE
408	def_bool PAHOLE_VERSION >= 124
409	help
410	  Support for the --lang_exclude flag which makes pahole exclude
411	  compilation units from the supplied language. Used in Kbuild to
412	  omit Rust CUs which are not supported in version 1.24 of pahole,
413	  otherwise it would emit malformed kernel and module binaries when
414	  using DEBUG_INFO_BTF_MODULES.
415
416config DEBUG_INFO_BTF_MODULES
417	bool "Generate BTF type information for kernel modules"
418	default y
419	depends on DEBUG_INFO_BTF && MODULES
420	help
421	  Generate compact split BTF type information for kernel modules.
422
423config MODULE_ALLOW_BTF_MISMATCH
424	bool "Allow loading modules with non-matching BTF type info"
425	depends on DEBUG_INFO_BTF_MODULES
426	help
427	  For modules whose split BTF does not match vmlinux, load without
428	  BTF rather than refusing to load. The default behavior with
429	  module BTF enabled is to reject modules with such mismatches;
430	  this option will still load module BTF where possible but ignore
431	  it when a mismatch is found.
432
433config GDB_SCRIPTS
434	bool "Provide GDB scripts for kernel debugging"
435	help
436	  This creates the required links to GDB helper scripts in the
437	  build directory. If you load vmlinux into gdb, the helper
438	  scripts will be automatically imported by gdb as well, and
439	  additional functions are available to analyze a Linux kernel
440	  instance. See Documentation/process/debugging/gdb-kernel-debugging.rst
441	  for further details.
442
443endif # DEBUG_INFO
444
445config FRAME_WARN
446	int "Warn for stack frames larger than"
447	range 0 8192
448	default 0 if KMSAN
449	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
450	default 2048 if PARISC
451	default 1536 if (!64BIT && XTENSA)
452	default 1280 if !64BIT
453	default 2048 if 64BIT
454	help
455	  Tell the compiler to warn at build time for stack frames larger than this.
456	  Setting this too low will cause a lot of warnings.
457	  Setting it to 0 disables the warning.
458
459config STRIP_ASM_SYMS
460	bool "Strip assembler-generated symbols during link"
461	default n
462	help
463	  Strip internal assembler-generated symbols during a link (symbols
464	  that look like '.Lxxx') so they don't pollute the output of
465	  get_wchan() and suchlike.
466
467config READABLE_ASM
468	bool "Generate readable assembler code"
469	depends on DEBUG_KERNEL
470	depends on CC_IS_GCC
471	help
472	  Disable some compiler optimizations that tend to generate human unreadable
473	  assembler output. This may make the kernel slightly slower, but it helps
474	  to keep kernel developers who have to stare a lot at assembler listings
475	  sane.
476
477config HEADERS_INSTALL
478	bool "Install uapi headers to usr/include"
479	help
480	  This option will install uapi headers (headers exported to user-space)
481	  into the usr/include directory for use during the kernel build.
482	  This is unneeded for building the kernel itself, but needed for some
483	  user-space program samples. It is also needed by some features such
484	  as uapi header sanity checks.
485
486config DEBUG_SECTION_MISMATCH
487	bool "Enable full Section mismatch analysis"
488	depends on CC_IS_GCC
489	help
490	  The section mismatch analysis checks if there are illegal references
491	  from one section to another. During linktime or runtime, some
492	  sections are dropped; any use of code/data previously in these
493	  sections would most likely result in an oops.
494
495	  In the code, functions and variables are annotated with __init,
496	  __initdata, and so on (see the full list in include/linux/init.h).
497	  This directs the toolchain to place code/data in specific sections.
498
499	  The section mismatch analysis is always performed after a full
500	  kernel build, and enabling this option causes the option
501	  -fno-inline-functions-called-once to be added to gcc commands.
502
503	  However, when inlining a function annotated with __init in
504	  a non-init function, we would lose the section information and thus
505	  the analysis would not catch the illegal reference.  This option
506	  tells gcc to inline less (but it does result in a larger kernel).
507
508config SECTION_MISMATCH_WARN_ONLY
509	bool "Make section mismatch errors non-fatal"
510	default y
511	help
512	  If you say N here, the build process will fail if there are any
513	  section mismatch, instead of just throwing warnings.
514
515	  If unsure, say Y.
516
517config DEBUG_FORCE_FUNCTION_ALIGN_64B
518	bool "Force all function address 64B aligned"
519	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390)
520	select FUNCTION_ALIGNMENT_64B
521	help
522	  There are cases that a commit from one domain changes the function
523	  address alignment of other domains, and cause magic performance
524	  bump (regression or improvement). Enable this option will help to
525	  verify if the bump is caused by function alignment changes, while
526	  it will slightly increase the kernel size and affect icache usage.
527
528	  It is mainly for debug and performance tuning use.
529
530#
531# Select this config option from the architecture Kconfig, if it
532# is preferred to always offer frame pointers as a config
533# option on the architecture (regardless of KERNEL_DEBUG):
534#
535config ARCH_WANT_FRAME_POINTERS
536	bool
537
538config FRAME_POINTER
539	bool "Compile the kernel with frame pointers"
540	depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
541	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
542	help
543	  If you say Y here the resulting kernel image will be slightly
544	  larger and slower, but it gives very useful debugging information
545	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
546
547config OBJTOOL
548	bool
549
550config OBJTOOL_WERROR
551	bool "Upgrade objtool warnings to errors"
552	depends on OBJTOOL && !COMPILE_TEST
553	help
554	  Fail the build on objtool warnings.
555
556	  Objtool warnings can indicate kernel instability, including boot
557	  failures.  This option is highly recommended.
558
559	  If unsure, say Y.
560
561config STACK_VALIDATION
562	bool "Compile-time stack metadata validation"
563	depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
564	select OBJTOOL
565	default n
566	help
567	  Validate frame pointer rules at compile-time.  This helps ensure that
568	  runtime stack traces are more reliable.
569
570	  For more information, see
571	  tools/objtool/Documentation/objtool.txt.
572
573config NOINSTR_VALIDATION
574	bool
575	depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
576	select OBJTOOL
577	default y
578
579config VMLINUX_MAP
580	bool "Generate vmlinux.map file when linking"
581	depends on EXPERT
582	help
583	  Selecting this option will pass "-Map=vmlinux.map" to ld
584	  when linking vmlinux. That file can be useful for verifying
585	  and debugging magic section games, and for seeing which
586	  pieces of code get eliminated with
587	  CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
588
589config BUILTIN_MODULE_RANGES
590	bool "Generate address range information for builtin modules"
591	depends on !LTO
592	depends on VMLINUX_MAP
593	help
594	 When modules are built into the kernel, there will be no module name
595	 associated with its symbols in /proc/kallsyms.  Tracers may want to
596	 identify symbols by module name and symbol name regardless of whether
597	 the module is configured as loadable or not.
598
599	 This option generates modules.builtin.ranges in the build tree with
600	 offset ranges (per ELF section) for the module(s) they belong to.
601	 It also records an anchor symbol to determine the load address of the
602	 section.
603
604config DEBUG_FORCE_WEAK_PER_CPU
605	bool "Force weak per-cpu definitions"
606	depends on DEBUG_KERNEL
607	help
608	  s390 and alpha require percpu variables in modules to be
609	  defined weak to work around addressing range issue which
610	  puts the following two restrictions on percpu variable
611	  definitions.
612
613	  1. percpu symbols must be unique whether static or not
614	  2. percpu variables can't be defined inside a function
615
616	  To ensure that generic code follows the above rules, this
617	  option forces all percpu variables to be defined as weak.
618
619endmenu # "Compiler options"
620
621menu "Generic Kernel Debugging Instruments"
622
623config MAGIC_SYSRQ
624	bool "Magic SysRq key"
625	depends on !UML
626	help
627	  If you say Y here, you will have some control over the system even
628	  if the system crashes for example during kernel debugging (e.g., you
629	  will be able to flush the buffer cache to disk, reboot the system
630	  immediately or dump some status information). This is accomplished
631	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
632	  also works on a serial console (on PC hardware at least), if you
633	  send a BREAK and then within 5 seconds a command keypress. The
634	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
635	  Don't say Y unless you really know what this hack does.
636
637config MAGIC_SYSRQ_DEFAULT_ENABLE
638	hex "Enable magic SysRq key functions by default"
639	depends on MAGIC_SYSRQ
640	default 0x1
641	help
642	  Specifies which SysRq key functions are enabled by default.
643	  This may be set to 1 or 0 to enable or disable them all, or
644	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
645
646config MAGIC_SYSRQ_SERIAL
647	bool "Enable magic SysRq key over serial"
648	depends on MAGIC_SYSRQ
649	default y
650	help
651	  Many embedded boards have a disconnected TTL level serial which can
652	  generate some garbage that can lead to spurious false sysrq detects.
653	  This option allows you to decide whether you want to enable the
654	  magic SysRq key.
655
656config MAGIC_SYSRQ_SERIAL_SEQUENCE
657	string "Char sequence that enables magic SysRq over serial"
658	depends on MAGIC_SYSRQ_SERIAL
659	default ""
660	help
661	  Specifies a sequence of characters that can follow BREAK to enable
662	  SysRq on a serial console.
663
664	  If unsure, leave an empty string and the option will not be enabled.
665
666config DEBUG_FS
667	bool "Debug Filesystem"
668	help
669	  debugfs is a virtual file system that kernel developers use to put
670	  debugging files into.  Enable this option to be able to read and
671	  write to these files.
672
673	  For detailed documentation on the debugfs API, see
674	  Documentation/filesystems/.
675
676	  If unsure, say N.
677
678choice
679	prompt "Debugfs default access"
680	depends on DEBUG_FS
681	default DEBUG_FS_ALLOW_ALL
682	help
683	  This selects the default access restrictions for debugfs.
684	  It can be overridden with kernel command line option
685	  debugfs=[on,off]. The restrictions apply for API access
686	  and filesystem registration.
687
688config DEBUG_FS_ALLOW_ALL
689	bool "Access normal"
690	help
691	  No restrictions apply. Both API and filesystem registration
692	  is on. This is the normal default operation.
693
694config DEBUG_FS_ALLOW_NONE
695	bool "No access"
696	help
697	  Access is off. Clients get -PERM when trying to create nodes in
698	  debugfs tree and debugfs is not registered as a filesystem.
699	  Client can then back-off or continue without debugfs access.
700
701endchoice
702
703source "lib/Kconfig.kgdb"
704source "lib/Kconfig.ubsan"
705source "lib/Kconfig.kcsan"
706
707endmenu
708
709menu "Networking Debugging"
710
711source "net/Kconfig.debug"
712
713endmenu # "Networking Debugging"
714
715menu "Memory Debugging"
716
717source "mm/Kconfig.debug"
718
719config DEBUG_OBJECTS
720	bool "Debug object operations"
721	depends on DEBUG_KERNEL
722	help
723	  If you say Y here, additional code will be inserted into the
724	  kernel to track the life time of various objects and validate
725	  the operations on those objects.
726
727config DEBUG_OBJECTS_SELFTEST
728	bool "Debug objects selftest"
729	depends on DEBUG_OBJECTS
730	help
731	  This enables the selftest of the object debug code.
732
733config DEBUG_OBJECTS_FREE
734	bool "Debug objects in freed memory"
735	depends on DEBUG_OBJECTS
736	help
737	  This enables checks whether a k/v free operation frees an area
738	  which contains an object which has not been deactivated
739	  properly. This can make kmalloc/kfree-intensive workloads
740	  much slower.
741
742config DEBUG_OBJECTS_TIMERS
743	bool "Debug timer objects"
744	depends on DEBUG_OBJECTS
745	help
746	  If you say Y here, additional code will be inserted into the
747	  timer routines to track the life time of timer objects and
748	  validate the timer operations.
749
750config DEBUG_OBJECTS_WORK
751	bool "Debug work objects"
752	depends on DEBUG_OBJECTS
753	help
754	  If you say Y here, additional code will be inserted into the
755	  work queue routines to track the life time of work objects and
756	  validate the work operations.
757
758config DEBUG_OBJECTS_RCU_HEAD
759	bool "Debug RCU callbacks objects"
760	depends on DEBUG_OBJECTS
761	help
762	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
763
764config DEBUG_OBJECTS_PERCPU_COUNTER
765	bool "Debug percpu counter objects"
766	depends on DEBUG_OBJECTS
767	help
768	  If you say Y here, additional code will be inserted into the
769	  percpu counter routines to track the life time of percpu counter
770	  objects and validate the percpu counter operations.
771
772config DEBUG_OBJECTS_ENABLE_DEFAULT
773	int "debug_objects bootup default value (0-1)"
774	range 0 1
775	default "1"
776	depends on DEBUG_OBJECTS
777	help
778	  Debug objects boot parameter default value
779
780config SHRINKER_DEBUG
781	bool "Enable shrinker debugging support"
782	depends on DEBUG_FS
783	help
784	  Say Y to enable the shrinker debugfs interface which provides
785	  visibility into the kernel memory shrinkers subsystem.
786	  Disable it to avoid an extra memory footprint.
787
788config DEBUG_STACK_USAGE
789	bool "Stack utilization instrumentation"
790	depends on DEBUG_KERNEL
791	help
792	  Enables the display of the minimum amount of free stack which each
793	  task has ever had available in the sysrq-T and sysrq-P debug output.
794	  Also emits a message to dmesg when a process exits if that process
795	  used more stack space than previously exiting processes.
796
797	  This option will slow down process creation somewhat.
798
799config SCHED_STACK_END_CHECK
800	bool "Detect stack corruption on calls to schedule()"
801	depends on DEBUG_KERNEL
802	default n
803	help
804	  This option checks for a stack overrun on calls to schedule().
805	  If the stack end location is found to be over written always panic as
806	  the content of the corrupted region can no longer be trusted.
807	  This is to ensure no erroneous behaviour occurs which could result in
808	  data corruption or a sporadic crash at a later stage once the region
809	  is examined. The runtime overhead introduced is minimal.
810
811config ARCH_HAS_DEBUG_VM_PGTABLE
812	bool
813	help
814	  An architecture should select this when it can successfully
815	  build and run DEBUG_VM_PGTABLE.
816
817config DEBUG_VFS
818	bool "Debug VFS"
819	depends on DEBUG_KERNEL
820	help
821	  Enable this to turn on extended checks in the VFS layer that may impact
822	  performance.
823
824	  If unsure, say N.
825
826config DEBUG_VM_IRQSOFF
827	def_bool DEBUG_VM && !PREEMPT_RT
828
829config DEBUG_VM
830	bool "Debug VM"
831	depends on DEBUG_KERNEL
832	help
833	  Enable this to turn on extended checks in the virtual-memory system
834	  that may impact performance.
835
836	  If unsure, say N.
837
838config DEBUG_VM_SHOOT_LAZIES
839	bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
840	depends on DEBUG_VM
841	depends on MMU_LAZY_TLB_SHOOTDOWN
842	help
843	  Enable additional IPIs that ensure lazy tlb mm references are removed
844	  before the mm is freed.
845
846	  If unsure, say N.
847
848config DEBUG_VM_MAPLE_TREE
849	bool "Debug VM maple trees"
850	depends on DEBUG_VM
851	select DEBUG_MAPLE_TREE
852	help
853	  Enable VM maple tree debugging information and extra validations.
854
855	  If unsure, say N.
856
857config DEBUG_VM_RB
858	bool "Debug VM red-black trees"
859	depends on DEBUG_VM
860	help
861	  Enable VM red-black tree debugging information and extra validations.
862
863	  If unsure, say N.
864
865config DEBUG_VM_PGFLAGS
866	bool "Debug page-flags operations"
867	depends on DEBUG_VM
868	help
869	  Enables extra validation on page flags operations.
870
871	  If unsure, say N.
872
873config DEBUG_VM_PGTABLE
874	bool "Debug arch page table for semantics compliance"
875	depends on MMU
876	depends on ARCH_HAS_DEBUG_VM_PGTABLE
877	default y if DEBUG_VM
878	help
879	  This option provides a debug method which can be used to test
880	  architecture page table helper functions on various platforms in
881	  verifying if they comply with expected generic MM semantics. This
882	  will help architecture code in making sure that any changes or
883	  new additions of these helpers still conform to expected
884	  semantics of the generic MM. Platforms will have to opt in for
885	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
886
887	  If unsure, say N.
888
889config ARCH_HAS_DEBUG_VIRTUAL
890	bool
891
892config DEBUG_VIRTUAL
893	bool "Debug VM translations"
894	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
895	help
896	  Enable some costly sanity checks in virtual to page code. This can
897	  catch mistakes with virt_to_page() and friends.
898
899	  If unsure, say N.
900
901config DEBUG_NOMMU_REGIONS
902	bool "Debug the global anon/private NOMMU mapping region tree"
903	depends on DEBUG_KERNEL && !MMU
904	help
905	  This option causes the global tree of anonymous and private mapping
906	  regions to be regularly checked for invalid topology.
907
908config DEBUG_MEMORY_INIT
909	bool "Debug memory initialisation" if EXPERT
910	default !EXPERT
911	help
912	  Enable this for additional checks during memory initialisation.
913	  The sanity checks verify aspects of the VM such as the memory model
914	  and other information provided by the architecture. Verbose
915	  information will be printed at KERN_DEBUG loglevel depending
916	  on the mminit_loglevel= command-line option.
917
918	  If unsure, say Y
919
920config MEMORY_NOTIFIER_ERROR_INJECT
921	tristate "Memory hotplug notifier error injection module"
922	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
923	help
924	  This option provides the ability to inject artificial errors to
925	  memory hotplug notifier chain callbacks.  It is controlled through
926	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
927
928	  If the notifier call chain should be failed with some events
929	  notified, write the error code to "actions/<notifier event>/error".
930
931	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
932
933	  # cd /sys/kernel/debug/notifier-error-inject/memory
934	  # echo -12 > actions/MEM_GOING_OFFLINE/error
935	  # echo offline > /sys/devices/system/memory/memoryXXX/state
936	  bash: echo: write error: Cannot allocate memory
937
938	  To compile this code as a module, choose M here: the module will
939	  be called memory-notifier-error-inject.
940
941	  If unsure, say N.
942
943config DEBUG_PER_CPU_MAPS
944	bool "Debug access to per_cpu maps"
945	depends on DEBUG_KERNEL
946	depends on SMP
947	help
948	  Say Y to verify that the per_cpu map being accessed has
949	  been set up. This adds a fair amount of code to kernel memory
950	  and decreases performance.
951
952	  Say N if unsure.
953
954config DEBUG_KMAP_LOCAL
955	bool "Debug kmap_local temporary mappings"
956	depends on DEBUG_KERNEL && KMAP_LOCAL
957	help
958	  This option enables additional error checking for the kmap_local
959	  infrastructure.  Disable for production use.
960
961config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
962	bool
963
964config DEBUG_KMAP_LOCAL_FORCE_MAP
965	bool "Enforce kmap_local temporary mappings"
966	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
967	select KMAP_LOCAL
968	select DEBUG_KMAP_LOCAL
969	help
970	  This option enforces temporary mappings through the kmap_local
971	  mechanism for non-highmem pages and on non-highmem systems.
972	  Disable this for production systems!
973
974config DEBUG_HIGHMEM
975	bool "Highmem debugging"
976	depends on DEBUG_KERNEL && HIGHMEM
977	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
978	select DEBUG_KMAP_LOCAL
979	help
980	  This option enables additional error checking for high memory
981	  systems.  Disable for production systems.
982
983config HAVE_DEBUG_STACKOVERFLOW
984	bool
985
986config DEBUG_STACKOVERFLOW
987	bool "Check for stack overflows"
988	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
989	help
990	  Say Y here if you want to check for overflows of kernel, IRQ
991	  and exception stacks (if your architecture uses them). This
992	  option will show detailed messages if free stack space drops
993	  below a certain limit.
994
995	  These kinds of bugs usually occur when call-chains in the
996	  kernel get too deep, especially when interrupts are
997	  involved.
998
999	  Use this in cases where you see apparently random memory
1000	  corruption, especially if it appears in 'struct thread_info'
1001
1002	  If in doubt, say "N".
1003
1004config CODE_TAGGING
1005	bool
1006	select KALLSYMS
1007
1008config MEM_ALLOC_PROFILING
1009	bool "Enable memory allocation profiling"
1010	default n
1011	depends on MMU
1012	depends on PROC_FS
1013	depends on !DEBUG_FORCE_WEAK_PER_CPU
1014	select CODE_TAGGING
1015	select PAGE_EXTENSION
1016	select SLAB_OBJ_EXT
1017	help
1018	  Track allocation source code and record total allocation size
1019	  initiated at that code location. The mechanism can be used to track
1020	  memory leaks with a low performance and memory impact.
1021
1022config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1023	bool "Enable memory allocation profiling by default"
1024	default y
1025	depends on MEM_ALLOC_PROFILING
1026
1027config MEM_ALLOC_PROFILING_DEBUG
1028	bool "Memory allocation profiler debugging"
1029	default n
1030	depends on MEM_ALLOC_PROFILING
1031	select MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1032	help
1033	  Adds warnings with helpful error messages for memory allocation
1034	  profiling.
1035
1036source "lib/Kconfig.kasan"
1037source "lib/Kconfig.kfence"
1038source "lib/Kconfig.kmsan"
1039
1040endmenu # "Memory Debugging"
1041
1042config DEBUG_SHIRQ
1043	bool "Debug shared IRQ handlers"
1044	depends on DEBUG_KERNEL
1045	help
1046	  Enable this to generate a spurious interrupt just before a shared
1047	  interrupt handler is deregistered (generating one when registering
1048	  is currently disabled). Drivers need to handle this correctly. Some
1049	  don't and need to be caught.
1050
1051menu "Debug Oops, Lockups and Hangs"
1052
1053config PANIC_ON_OOPS
1054	bool "Panic on Oops"
1055	help
1056	  Say Y here to enable the kernel to panic when it oopses. This
1057	  has the same effect as setting oops=panic on the kernel command
1058	  line.
1059
1060	  This feature is useful to ensure that the kernel does not do
1061	  anything erroneous after an oops which could result in data
1062	  corruption or other issues.
1063
1064	  Say N if unsure.
1065
1066config PANIC_TIMEOUT
1067	int "panic timeout"
1068	default 0
1069	help
1070	  Set the timeout value (in seconds) until a reboot occurs when
1071	  the kernel panics. If n = 0, then we wait forever. A timeout
1072	  value n > 0 will wait n seconds before rebooting, while a timeout
1073	  value n < 0 will reboot immediately. This setting can be overridden
1074	  with the kernel command line option panic=, and from userspace via
1075	  /proc/sys/kernel/panic.
1076
1077config LOCKUP_DETECTOR
1078	bool
1079
1080config SOFTLOCKUP_DETECTOR
1081	bool "Detect Soft Lockups"
1082	depends on DEBUG_KERNEL && !S390
1083	select LOCKUP_DETECTOR
1084	help
1085	  Say Y here to enable the kernel to act as a watchdog to detect
1086	  soft lockups.
1087
1088	  Softlockups are bugs that cause the kernel to loop in kernel
1089	  mode for more than 20 seconds, without giving other tasks a
1090	  chance to run.  The current stack trace is displayed upon
1091	  detection and the system will stay locked up.
1092
1093config SOFTLOCKUP_DETECTOR_INTR_STORM
1094	bool "Detect Interrupt Storm in Soft Lockups"
1095	depends on SOFTLOCKUP_DETECTOR && IRQ_TIME_ACCOUNTING
1096	select GENERIC_IRQ_STAT_SNAPSHOT
1097	default y if NR_CPUS <= 128
1098	help
1099	  Say Y here to enable the kernel to detect interrupt storm
1100	  during "soft lockups".
1101
1102	  "soft lockups" can be caused by a variety of reasons. If one is
1103	  caused by an interrupt storm, then the storming interrupts will not
1104	  be on the callstack. To detect this case, it is necessary to report
1105	  the CPU stats and the interrupt counts during the "soft lockups".
1106
1107config BOOTPARAM_SOFTLOCKUP_PANIC
1108	bool "Panic (Reboot) On Soft Lockups"
1109	depends on SOFTLOCKUP_DETECTOR
1110	help
1111	  Say Y here to enable the kernel to panic on "soft lockups",
1112	  which are bugs that cause the kernel to loop in kernel
1113	  mode for more than 20 seconds (configurable using the watchdog_thresh
1114	  sysctl), without giving other tasks a chance to run.
1115
1116	  The panic can be used in combination with panic_timeout,
1117	  to cause the system to reboot automatically after a
1118	  lockup has been detected. This feature is useful for
1119	  high-availability systems that have uptime guarantees and
1120	  where a lockup must be resolved ASAP.
1121
1122	  Say N if unsure.
1123
1124config HAVE_HARDLOCKUP_DETECTOR_BUDDY
1125	bool
1126	depends on SMP
1127	default y
1128
1129#
1130# Global switch whether to build a hardlockup detector at all. It is available
1131# only when the architecture supports at least one implementation. There are
1132# two exceptions. The hardlockup detector is never enabled on:
1133#
1134#	s390: it reported many false positives there
1135#
1136#	sparc64: has a custom implementation which is not using the common
1137#		hardlockup command line options and sysctl interface.
1138#
1139config HARDLOCKUP_DETECTOR
1140	bool "Detect Hard Lockups"
1141	depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
1142	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
1143	imply HARDLOCKUP_DETECTOR_PERF
1144	imply HARDLOCKUP_DETECTOR_BUDDY
1145	imply HARDLOCKUP_DETECTOR_ARCH
1146	select LOCKUP_DETECTOR
1147
1148	help
1149	  Say Y here to enable the kernel to act as a watchdog to detect
1150	  hard lockups.
1151
1152	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1153	  for more than 10 seconds, without letting other interrupts have a
1154	  chance to run.  The current stack trace is displayed upon detection
1155	  and the system will stay locked up.
1156
1157#
1158# Note that arch-specific variants are always preferred.
1159#
1160config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1161	bool "Prefer the buddy CPU hardlockup detector"
1162	depends on HARDLOCKUP_DETECTOR
1163	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
1164	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1165	help
1166	  Say Y here to prefer the buddy hardlockup detector over the perf one.
1167
1168	  With the buddy detector, each CPU uses its softlockup hrtimer
1169	  to check that the next CPU is processing hrtimer interrupts by
1170	  verifying that a counter is increasing.
1171
1172	  This hardlockup detector is useful on systems that don't have
1173	  an arch-specific hardlockup detector or if resources needed
1174	  for the hardlockup detector are better used for other things.
1175
1176config HARDLOCKUP_DETECTOR_PERF
1177	bool
1178	depends on HARDLOCKUP_DETECTOR
1179	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
1180	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1181	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1182
1183config HARDLOCKUP_DETECTOR_BUDDY
1184	bool
1185	depends on HARDLOCKUP_DETECTOR
1186	depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1187	depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
1188	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1189	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1190
1191config HARDLOCKUP_DETECTOR_ARCH
1192	bool
1193	depends on HARDLOCKUP_DETECTOR
1194	depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1195	help
1196	  The arch-specific implementation of the hardlockup detector will
1197	  be used.
1198
1199#
1200# Both the "perf" and "buddy" hardlockup detectors count hrtimer
1201# interrupts. This config enables functions managing this common code.
1202#
1203config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1204	bool
1205	select SOFTLOCKUP_DETECTOR
1206
1207#
1208# Enables a timestamp based low pass filter to compensate for perf based
1209# hard lockup detection which runs too fast due to turbo modes.
1210#
1211config HARDLOCKUP_CHECK_TIMESTAMP
1212	bool
1213
1214config BOOTPARAM_HARDLOCKUP_PANIC
1215	bool "Panic (Reboot) On Hard Lockups"
1216	depends on HARDLOCKUP_DETECTOR
1217	help
1218	  Say Y here to enable the kernel to panic on "hard lockups",
1219	  which are bugs that cause the kernel to loop in kernel
1220	  mode with interrupts disabled for more than 10 seconds (configurable
1221	  using the watchdog_thresh sysctl).
1222
1223	  Say N if unsure.
1224
1225config DETECT_HUNG_TASK
1226	bool "Detect Hung Tasks"
1227	depends on DEBUG_KERNEL
1228	default SOFTLOCKUP_DETECTOR
1229	help
1230	  Say Y here to enable the kernel to detect "hung tasks",
1231	  which are bugs that cause the task to be stuck in
1232	  uninterruptible "D" state indefinitely.
1233
1234	  When a hung task is detected, the kernel will print the
1235	  current stack trace (which you should report), but the
1236	  task will stay in uninterruptible state. If lockdep is
1237	  enabled then all held locks will also be reported. This
1238	  feature has negligible overhead.
1239
1240config DEFAULT_HUNG_TASK_TIMEOUT
1241	int "Default timeout for hung task detection (in seconds)"
1242	depends on DETECT_HUNG_TASK
1243	default 120
1244	help
1245	  This option controls the default timeout (in seconds) used
1246	  to determine when a task has become non-responsive and should
1247	  be considered hung.
1248
1249	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1250	  sysctl or by writing a value to
1251	  /proc/sys/kernel/hung_task_timeout_secs.
1252
1253	  A timeout of 0 disables the check.  The default is two minutes.
1254	  Keeping the default should be fine in most cases.
1255
1256config BOOTPARAM_HUNG_TASK_PANIC
1257	int "Number of hung tasks to trigger kernel panic"
1258	depends on DETECT_HUNG_TASK
1259	default 0
1260	help
1261	  When set to a non-zero value, a kernel panic will be triggered
1262	  if the number of hung tasks found during a single scan reaches
1263	  this value.
1264
1265	  The panic can be used in combination with panic_timeout,
1266	  to cause the system to reboot automatically after a
1267	  hung task has been detected. This feature is useful for
1268	  high-availability systems that have uptime guarantees and
1269	  where a hung tasks must be resolved ASAP.
1270
1271	  Say N if unsure.
1272
1273config DETECT_HUNG_TASK_BLOCKER
1274	bool "Dump Hung Tasks Blocker"
1275	depends on DETECT_HUNG_TASK
1276	depends on !PREEMPT_RT
1277	default y
1278	help
1279	  Say Y here to show the blocker task's stacktrace who acquires
1280	  the mutex lock which "hung tasks" are waiting.
1281	  This will add overhead a bit but shows suspicious tasks and
1282	  call trace if it comes from waiting a mutex.
1283
1284config WQ_WATCHDOG
1285	bool "Detect Workqueue Stalls"
1286	depends on DEBUG_KERNEL
1287	help
1288	  Say Y here to enable stall detection on workqueues.  If a
1289	  worker pool doesn't make forward progress on a pending work
1290	  item for over a given amount of time, 30s by default, a
1291	  warning message is printed along with dump of workqueue
1292	  state.  This can be configured through kernel parameter
1293	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1294
1295config WQ_CPU_INTENSIVE_REPORT
1296	bool "Report per-cpu work items which hog CPU for too long"
1297	depends on DEBUG_KERNEL
1298	help
1299	  Say Y here to enable reporting of concurrency-managed per-cpu work
1300	  items that hog CPUs for longer than
1301	  workqueue.cpu_intensive_thresh_us. Workqueue automatically
1302	  detects and excludes them from concurrency management to prevent
1303	  them from stalling other per-cpu work items. Occassional
1304	  triggering may not necessarily indicate a problem. Repeated
1305	  triggering likely indicates that the work item should be switched
1306	  to use an unbound workqueue.
1307
1308config TEST_LOCKUP
1309	tristate "Test module to generate lockups"
1310	depends on m
1311	help
1312	  This builds the "test_lockup" module that helps to make sure
1313	  that watchdogs and lockup detectors are working properly.
1314
1315	  Depending on module parameters it could emulate soft or hard
1316	  lockup, "hung task", or locking arbitrary lock for a long time.
1317	  Also it could generate series of lockups with cooling-down periods.
1318
1319	  If unsure, say N.
1320
1321endmenu # "Debug lockups and hangs"
1322
1323menu "Scheduler Debugging"
1324
1325config SCHED_INFO
1326	bool
1327	default n
1328
1329config SCHEDSTATS
1330	bool "Collect scheduler statistics"
1331	depends on PROC_FS
1332	select SCHED_INFO
1333	help
1334	  If you say Y here, additional code will be inserted into the
1335	  scheduler and related routines to collect statistics about
1336	  scheduler behavior and provide them in /proc/schedstat.  These
1337	  stats may be useful for both tuning and debugging the scheduler
1338	  If you aren't debugging the scheduler or trying to tune a specific
1339	  application, you can say N to avoid the very slight overhead
1340	  this adds.
1341
1342endmenu
1343
1344config DEBUG_PREEMPT
1345	bool "Debug preemptible kernel"
1346	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1347	help
1348	  If you say Y here then the kernel will use a debug variant of the
1349	  commonly used smp_processor_id() function and will print warnings
1350	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1351	  will detect preemption count underflows.
1352
1353	  This option has potential to introduce high runtime overhead,
1354	  depending on workload as it triggers debugging routines for each
1355	  this_cpu operation. It should only be used for debugging purposes.
1356
1357menu "Lock Debugging (spinlocks, mutexes, etc...)"
1358
1359config LOCK_DEBUGGING_SUPPORT
1360	bool
1361	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1362	default y
1363
1364config PROVE_LOCKING
1365	bool "Lock debugging: prove locking correctness"
1366	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1367	select LOCKDEP
1368	select DEBUG_SPINLOCK
1369	select DEBUG_MUTEXES if !PREEMPT_RT
1370	select DEBUG_RT_MUTEXES if RT_MUTEXES
1371	select DEBUG_RWSEMS if !PREEMPT_RT
1372	select DEBUG_WW_MUTEX_SLOWPATH
1373	select DEBUG_LOCK_ALLOC
1374	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1375	select TRACE_IRQFLAGS
1376	default n
1377	help
1378	 This feature enables the kernel to prove that all locking
1379	 that occurs in the kernel runtime is mathematically
1380	 correct: that under no circumstance could an arbitrary (and
1381	 not yet triggered) combination of observed locking
1382	 sequences (on an arbitrary number of CPUs, running an
1383	 arbitrary number of tasks and interrupt contexts) cause a
1384	 deadlock.
1385
1386	 In short, this feature enables the kernel to report locking
1387	 related deadlocks before they actually occur.
1388
1389	 The proof does not depend on how hard and complex a
1390	 deadlock scenario would be to trigger: how many
1391	 participant CPUs, tasks and irq-contexts would be needed
1392	 for it to trigger. The proof also does not depend on
1393	 timing: if a race and a resulting deadlock is possible
1394	 theoretically (no matter how unlikely the race scenario
1395	 is), it will be proven so and will immediately be
1396	 reported by the kernel (once the event is observed that
1397	 makes the deadlock theoretically possible).
1398
1399	 If a deadlock is impossible (i.e. the locking rules, as
1400	 observed by the kernel, are mathematically correct), the
1401	 kernel reports nothing.
1402
1403	 NOTE: this feature can also be enabled for rwlocks, mutexes
1404	 and rwsems - in which case all dependencies between these
1405	 different locking variants are observed and mapped too, and
1406	 the proof of observed correctness is also maintained for an
1407	 arbitrary combination of these separate locking variants.
1408
1409	 For more details, see Documentation/locking/lockdep-design.rst.
1410
1411config PROVE_RAW_LOCK_NESTING
1412	bool "Enable raw_spinlock - spinlock nesting checks" if !ARCH_SUPPORTS_RT
1413	depends on PROVE_LOCKING
1414	default y if ARCH_SUPPORTS_RT
1415	help
1416	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1417	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1418	 not violated.
1419
1420config LOCK_STAT
1421	bool "Lock usage statistics"
1422	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1423	select LOCKDEP
1424	select DEBUG_SPINLOCK
1425	select DEBUG_MUTEXES if !PREEMPT_RT
1426	select DEBUG_RT_MUTEXES if RT_MUTEXES
1427	select DEBUG_LOCK_ALLOC
1428	default n
1429	help
1430	 This feature enables tracking lock contention points
1431
1432	 For more details, see Documentation/locking/lockstat.rst
1433
1434	 This also enables lock events required by "perf lock",
1435	 subcommand of perf.
1436	 If you want to use "perf lock", you also need to turn on
1437	 CONFIG_EVENT_TRACING.
1438
1439	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1440	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1441
1442config DEBUG_RT_MUTEXES
1443	bool "RT Mutex debugging, deadlock detection"
1444	depends on DEBUG_KERNEL && RT_MUTEXES
1445	help
1446	 This allows rt mutex semantics violations and rt mutex related
1447	 deadlocks (lockups) to be detected and reported automatically.
1448
1449config DEBUG_SPINLOCK
1450	bool "Spinlock and rw-lock debugging: basic checks"
1451	depends on DEBUG_KERNEL
1452	select UNINLINE_SPIN_UNLOCK
1453	help
1454	  Say Y here and build SMP to catch missing spinlock initialization
1455	  and certain other kinds of spinlock errors commonly made.  This is
1456	  best used in conjunction with the NMI watchdog so that spinlock
1457	  deadlocks are also debuggable.
1458
1459config DEBUG_MUTEXES
1460	bool "Mutex debugging: basic checks"
1461	depends on DEBUG_KERNEL && !PREEMPT_RT
1462	help
1463	 This feature allows mutex semantics violations to be detected and
1464	 reported.
1465
1466config DEBUG_WW_MUTEX_SLOWPATH
1467	bool "Wait/wound mutex debugging: Slowpath testing"
1468	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1469	select DEBUG_LOCK_ALLOC
1470	select DEBUG_SPINLOCK
1471	select DEBUG_MUTEXES if !PREEMPT_RT
1472	select DEBUG_RT_MUTEXES if PREEMPT_RT
1473	help
1474	 This feature enables slowpath testing for w/w mutex users by
1475	 injecting additional -EDEADLK wound/backoff cases. Together with
1476	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1477	 will test all possible w/w mutex interface abuse with the
1478	 exception of simply not acquiring all the required locks.
1479	 Note that this feature can introduce significant overhead, so
1480	 it really should not be enabled in a production or distro kernel,
1481	 even a debug kernel.  If you are a driver writer, enable it.  If
1482	 you are a distro, do not.
1483
1484config DEBUG_RWSEMS
1485	bool "RW Semaphore debugging: basic checks"
1486	depends on DEBUG_KERNEL && !PREEMPT_RT
1487	help
1488	  This debugging feature allows mismatched rw semaphore locks
1489	  and unlocks to be detected and reported.
1490
1491config DEBUG_LOCK_ALLOC
1492	bool "Lock debugging: detect incorrect freeing of live locks"
1493	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1494	select DEBUG_SPINLOCK
1495	select DEBUG_MUTEXES if !PREEMPT_RT
1496	select DEBUG_RT_MUTEXES if RT_MUTEXES
1497	select LOCKDEP
1498	help
1499	 This feature will check whether any held lock (spinlock, rwlock,
1500	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1501	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1502	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1503	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1504	 held during task exit.
1505
1506config LOCKDEP
1507	bool
1508	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1509	select STACKTRACE
1510	select KALLSYMS
1511	select KALLSYMS_ALL
1512
1513config LOCKDEP_SMALL
1514	bool
1515
1516config LOCKDEP_BITS
1517	int "Size for MAX_LOCKDEP_ENTRIES (as Nth power of 2)"
1518	depends on LOCKDEP && !LOCKDEP_SMALL
1519	range 10 24
1520	default 15
1521	help
1522	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1523
1524config LOCKDEP_CHAINS_BITS
1525	int "Size for MAX_LOCKDEP_CHAINS (as Nth power of 2)"
1526	depends on LOCKDEP && !LOCKDEP_SMALL
1527	range 10 21
1528	default 16
1529	help
1530	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1531
1532config LOCKDEP_STACK_TRACE_BITS
1533	int "Size for MAX_STACK_TRACE_ENTRIES (as Nth power of 2)"
1534	depends on LOCKDEP && !LOCKDEP_SMALL
1535	range 10 26
1536	default 19
1537	help
1538	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1539
1540config LOCKDEP_STACK_TRACE_HASH_BITS
1541	int "Size for STACK_TRACE_HASH_SIZE (as Nth power of 2)"
1542	depends on LOCKDEP && !LOCKDEP_SMALL
1543	range 10 26
1544	default 14
1545	help
1546	  Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1547
1548config LOCKDEP_CIRCULAR_QUEUE_BITS
1549	int "Size for elements in circular_queue struct (as Nth power of 2)"
1550	depends on LOCKDEP
1551	range 10 26
1552	default 12
1553	help
1554	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1555
1556config DEBUG_LOCKDEP
1557	bool "Lock dependency engine debugging"
1558	depends on DEBUG_KERNEL && LOCKDEP
1559	select DEBUG_IRQFLAGS
1560	help
1561	  If you say Y here, the lock dependency engine will do
1562	  additional runtime checks to debug itself, at the price
1563	  of more runtime overhead.
1564
1565config DEBUG_ATOMIC_SLEEP
1566	bool "Sleep inside atomic section checking"
1567	select PREEMPT_COUNT
1568	depends on DEBUG_KERNEL
1569	depends on !ARCH_NO_PREEMPT
1570	help
1571	  If you say Y here, various routines which may sleep will become very
1572	  noisy if they are called inside atomic sections: when a spinlock is
1573	  held, inside an rcu read side critical section, inside preempt disabled
1574	  sections, inside an interrupt, etc...
1575
1576config DEBUG_LOCKING_API_SELFTESTS
1577	bool "Locking API boot-time self-tests"
1578	depends on DEBUG_KERNEL
1579	help
1580	  Say Y here if you want the kernel to run a short self-test during
1581	  bootup. The self-test checks whether common types of locking bugs
1582	  are detected by debugging mechanisms or not. (if you disable
1583	  lock debugging then those bugs won't be detected of course.)
1584	  The following locking APIs are covered: spinlocks, rwlocks,
1585	  mutexes and rwsems.
1586
1587config LOCK_TORTURE_TEST
1588	tristate "torture tests for locking"
1589	depends on DEBUG_KERNEL
1590	select TORTURE_TEST
1591	help
1592	  This option provides a kernel module that runs torture tests
1593	  on kernel locking primitives.  The kernel module may be built
1594	  after the fact on the running kernel to be tested, if desired.
1595
1596	  Say Y here if you want kernel locking-primitive torture tests
1597	  to be built into the kernel.
1598	  Say M if you want these torture tests to build as a module.
1599	  Say N if you are unsure.
1600
1601config WW_MUTEX_SELFTEST
1602	tristate "Wait/wound mutex selftests"
1603	help
1604	  This option provides a kernel module that runs tests on the
1605	  on the struct ww_mutex locking API.
1606
1607	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1608	  with this test harness.
1609
1610	  Say M if you want these self tests to build as a module.
1611	  Say N if you are unsure.
1612
1613config SCF_TORTURE_TEST
1614	tristate "torture tests for smp_call_function*()"
1615	depends on DEBUG_KERNEL
1616	select TORTURE_TEST
1617	help
1618	  This option provides a kernel module that runs torture tests
1619	  on the smp_call_function() family of primitives.  The kernel
1620	  module may be built after the fact on the running kernel to
1621	  be tested, if desired.
1622
1623config CSD_LOCK_WAIT_DEBUG
1624	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1625	depends on DEBUG_KERNEL
1626	depends on SMP
1627	depends on 64BIT
1628	default n
1629	help
1630	  This option enables debug prints when CPUs are slow to respond
1631	  to the smp_call_function*() IPI wrappers.  These debug prints
1632	  include the IPI handler function currently executing (if any)
1633	  and relevant stack traces.
1634
1635config CSD_LOCK_WAIT_DEBUG_DEFAULT
1636	bool "Default csd_lock_wait() debugging on at boot time"
1637	depends on CSD_LOCK_WAIT_DEBUG
1638	depends on 64BIT
1639	default n
1640	help
1641	  This option causes the csdlock_debug= kernel boot parameter to
1642	  default to 1 (basic debugging) instead of 0 (no debugging).
1643
1644endmenu # lock debugging
1645
1646config TRACE_IRQFLAGS
1647	depends on TRACE_IRQFLAGS_SUPPORT
1648	bool
1649	help
1650	  Enables hooks to interrupt enabling and disabling for
1651	  either tracing or lock debugging.
1652
1653config TRACE_IRQFLAGS_NMI
1654	def_bool y
1655	depends on TRACE_IRQFLAGS
1656	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1657
1658config NMI_CHECK_CPU
1659	bool "Debugging for CPUs failing to respond to backtrace requests"
1660	depends on DEBUG_KERNEL
1661	depends on X86
1662	default n
1663	help
1664	  Enables debug prints when a CPU fails to respond to a given
1665	  backtrace NMI.  These prints provide some reasons why a CPU
1666	  might legitimately be failing to respond, for example, if it
1667	  is offline of if ignore_nmis is set.
1668
1669config DEBUG_IRQFLAGS
1670	bool "Debug IRQ flag manipulation"
1671	help
1672	  Enables checks for potentially unsafe enabling or disabling of
1673	  interrupts, such as calling raw_local_irq_restore() when interrupts
1674	  are enabled.
1675
1676config STACKTRACE
1677	bool "Stack backtrace support"
1678	depends on STACKTRACE_SUPPORT
1679	help
1680	  This option causes the kernel to create a /proc/pid/stack for
1681	  every process, showing its current stack trace.
1682	  It is also used by various kernel debugging features that require
1683	  stack trace generation.
1684
1685config WARN_ALL_UNSEEDED_RANDOM
1686	bool "Warn for all uses of unseeded randomness"
1687	default n
1688	help
1689	  Some parts of the kernel contain bugs relating to their use of
1690	  cryptographically secure random numbers before it's actually possible
1691	  to generate those numbers securely. This setting ensures that these
1692	  flaws don't go unnoticed, by enabling a message, should this ever
1693	  occur. This will allow people with obscure setups to know when things
1694	  are going wrong, so that they might contact developers about fixing
1695	  it.
1696
1697	  Unfortunately, on some models of some architectures getting
1698	  a fully seeded CRNG is extremely difficult, and so this can
1699	  result in dmesg getting spammed for a surprisingly long
1700	  time.  This is really bad from a security perspective, and
1701	  so architecture maintainers really need to do what they can
1702	  to get the CRNG seeded sooner after the system is booted.
1703	  However, since users cannot do anything actionable to
1704	  address this, by default this option is disabled.
1705
1706	  Say Y here if you want to receive warnings for all uses of
1707	  unseeded randomness.  This will be of use primarily for
1708	  those developers interested in improving the security of
1709	  Linux kernels running on their architecture (or
1710	  subarchitecture).
1711
1712config DEBUG_KOBJECT
1713	bool "kobject debugging"
1714	depends on DEBUG_KERNEL
1715	help
1716	  If you say Y here, some extra kobject debugging messages will be sent
1717	  to the syslog.
1718
1719config DEBUG_KOBJECT_RELEASE
1720	bool "kobject release debugging"
1721	depends on DEBUG_OBJECTS_TIMERS
1722	help
1723	  kobjects are reference counted objects.  This means that their
1724	  last reference count put is not predictable, and the kobject can
1725	  live on past the point at which a driver decides to drop its
1726	  initial reference to the kobject gained on allocation.  An
1727	  example of this would be a struct device which has just been
1728	  unregistered.
1729
1730	  However, some buggy drivers assume that after such an operation,
1731	  the memory backing the kobject can be immediately freed.  This
1732	  goes completely against the principles of a refcounted object.
1733
1734	  If you say Y here, the kernel will delay the release of kobjects
1735	  on the last reference count to improve the visibility of this
1736	  kind of kobject release bug.
1737
1738config HAVE_DEBUG_BUGVERBOSE
1739	bool
1740
1741menu "Debug kernel data structures"
1742
1743config DEBUG_LIST
1744	bool "Debug linked list manipulation"
1745	depends on DEBUG_KERNEL
1746	select LIST_HARDENED
1747	help
1748	  Enable this to turn on extended checks in the linked-list walking
1749	  routines.
1750
1751	  This option trades better quality error reports for performance, and
1752	  is more suitable for kernel debugging. If you care about performance,
1753	  you should only enable CONFIG_LIST_HARDENED instead.
1754
1755	  If unsure, say N.
1756
1757config DEBUG_PLIST
1758	bool "Debug priority linked list manipulation"
1759	depends on DEBUG_KERNEL
1760	help
1761	  Enable this to turn on extended checks in the priority-ordered
1762	  linked-list (plist) walking routines.  This checks the entire
1763	  list multiple times during each manipulation.
1764
1765	  If unsure, say N.
1766
1767config DEBUG_SG
1768	bool "Debug SG table operations"
1769	depends on DEBUG_KERNEL
1770	help
1771	  Enable this to turn on checks on scatter-gather tables. This can
1772	  help find problems with drivers that do not properly initialize
1773	  their sg tables.
1774
1775	  If unsure, say N.
1776
1777config DEBUG_NOTIFIERS
1778	bool "Debug notifier call chains"
1779	depends on DEBUG_KERNEL
1780	help
1781	  Enable this to turn on sanity checking for notifier call chains.
1782	  This is most useful for kernel developers to make sure that
1783	  modules properly unregister themselves from notifier chains.
1784	  This is a relatively cheap check but if you care about maximum
1785	  performance, say N.
1786
1787config DEBUG_CLOSURES
1788	bool "Debug closures (bcache async widgits)"
1789	depends on CLOSURES
1790	select DEBUG_FS
1791	help
1792	  Keeps all active closures in a linked list and provides a debugfs
1793	  interface to list them, which makes it possible to see asynchronous
1794	  operations that get stuck.
1795
1796config DEBUG_MAPLE_TREE
1797	bool "Debug maple trees"
1798	depends on DEBUG_KERNEL
1799	help
1800	  Enable maple tree debugging information and extra validations.
1801
1802	  If unsure, say N.
1803
1804endmenu
1805
1806source "kernel/rcu/Kconfig.debug"
1807
1808config DEBUG_WQ_FORCE_RR_CPU
1809	bool "Force round-robin CPU selection for unbound work items"
1810	depends on DEBUG_KERNEL
1811	default n
1812	help
1813	  Workqueue used to implicitly guarantee that work items queued
1814	  without explicit CPU specified are put on the local CPU.  This
1815	  guarantee is no longer true and while local CPU is still
1816	  preferred work items may be put on foreign CPUs.  Kernel
1817	  parameter "workqueue.debug_force_rr_cpu" is added to force
1818	  round-robin CPU selection to flush out usages which depend on the
1819	  now broken guarantee.  This config option enables the debug
1820	  feature by default.  When enabled, memory and cache locality will
1821	  be impacted.
1822
1823config CPU_HOTPLUG_STATE_CONTROL
1824	bool "Enable CPU hotplug state control"
1825	depends on DEBUG_KERNEL
1826	depends on HOTPLUG_CPU
1827	default n
1828	help
1829	  Allows to write steps between "offline" and "online" to the CPUs
1830	  sysfs target file so states can be stepped granular. This is a debug
1831	  option for now as the hotplug machinery cannot be stopped and
1832	  restarted at arbitrary points yet.
1833
1834	  Say N if your are unsure.
1835
1836config LATENCYTOP
1837	bool "Latency measuring infrastructure"
1838	depends on DEBUG_KERNEL
1839	depends on STACKTRACE_SUPPORT
1840	depends on PROC_FS
1841	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1842	select KALLSYMS
1843	select KALLSYMS_ALL
1844	select STACKTRACE
1845	select SCHEDSTATS
1846	help
1847	  Enable this option if you want to use the LatencyTOP tool
1848	  to find out which userspace is blocking on what kernel operations.
1849
1850config DEBUG_CGROUP_REF
1851	bool "Disable inlining of cgroup css reference count functions"
1852	depends on DEBUG_KERNEL
1853	depends on CGROUPS
1854	depends on KPROBES
1855	default n
1856	help
1857	  Force cgroup css reference count functions to not be inlined so
1858	  that they can be kprobed for debugging.
1859
1860source "kernel/trace/Kconfig"
1861
1862config PROVIDE_OHCI1394_DMA_INIT
1863	bool "Remote debugging over FireWire early on boot"
1864	depends on PCI && X86
1865	help
1866	  If you want to debug problems which hang or crash the kernel early
1867	  on boot and the crashing machine has a FireWire port, you can use
1868	  this feature to remotely access the memory of the crashed machine
1869	  over FireWire. This employs remote DMA as part of the OHCI1394
1870	  specification which is now the standard for FireWire controllers.
1871
1872	  With remote DMA, you can monitor the printk buffer remotely using
1873	  firescope and access all memory below 4GB using fireproxy from gdb.
1874	  Even controlling a kernel debugger is possible using remote DMA.
1875
1876	  Usage:
1877
1878	  If ohci1394_dma=early is used as boot parameter, it will initialize
1879	  all OHCI1394 controllers which are found in the PCI config space.
1880
1881	  As all changes to the FireWire bus such as enabling and disabling
1882	  devices cause a bus reset and thereby disable remote DMA for all
1883	  devices, be sure to have the cable plugged and FireWire enabled on
1884	  the debugging host before booting the debug target for debugging.
1885
1886	  This code (~1k) is freed after boot. By then, the firewire stack
1887	  in charge of the OHCI-1394 controllers should be used instead.
1888
1889	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1890
1891source "samples/Kconfig"
1892
1893config ARCH_HAS_DEVMEM_IS_ALLOWED
1894	bool
1895
1896config STRICT_DEVMEM
1897	bool "Filter access to /dev/mem"
1898	depends on MMU && DEVMEM
1899	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1900	default y if PPC || X86 || ARM64 || S390
1901	help
1902	  If this option is disabled, you allow userspace (root) access to all
1903	  of memory, including kernel and userspace memory. Accidental
1904	  access to this is obviously disastrous, but specific access can
1905	  be used by people debugging the kernel. Note that with PAT support
1906	  enabled, even in this case there are restrictions on /dev/mem
1907	  use due to the cache aliasing requirements.
1908
1909	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1910	  file only allows userspace access to PCI space and the BIOS code and
1911	  data regions.  This is sufficient for dosemu and X and all common
1912	  users of /dev/mem.
1913
1914	  If in doubt, say Y.
1915
1916config IO_STRICT_DEVMEM
1917	bool "Filter I/O access to /dev/mem"
1918	depends on STRICT_DEVMEM
1919	help
1920	  If this option is disabled, you allow userspace (root) access to all
1921	  io-memory regardless of whether a driver is actively using that
1922	  range.  Accidental access to this is obviously disastrous, but
1923	  specific access can be used by people debugging kernel drivers.
1924
1925	  If this option is switched on, the /dev/mem file only allows
1926	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1927	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1928	  if the driver using a given range cannot be disabled.
1929
1930	  If in doubt, say Y.
1931
1932menu "$(SRCARCH) Debugging"
1933
1934source "arch/$(SRCARCH)/Kconfig.debug"
1935
1936endmenu
1937
1938menu "Kernel Testing and Coverage"
1939
1940source "lib/kunit/Kconfig"
1941
1942config NOTIFIER_ERROR_INJECTION
1943	tristate "Notifier error injection"
1944	depends on DEBUG_KERNEL
1945	select DEBUG_FS
1946	help
1947	  This option provides the ability to inject artificial errors to
1948	  specified notifier chain callbacks. It is useful to test the error
1949	  handling of notifier call chain failures.
1950
1951	  Say N if unsure.
1952
1953config PM_NOTIFIER_ERROR_INJECT
1954	tristate "PM notifier error injection module"
1955	depends on PM && NOTIFIER_ERROR_INJECTION
1956	default m if PM_DEBUG
1957	help
1958	  This option provides the ability to inject artificial errors to
1959	  PM notifier chain callbacks.  It is controlled through debugfs
1960	  interface /sys/kernel/debug/notifier-error-inject/pm
1961
1962	  If the notifier call chain should be failed with some events
1963	  notified, write the error code to "actions/<notifier event>/error".
1964
1965	  Example: Inject PM suspend error (-12 = -ENOMEM)
1966
1967	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1968	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1969	  # echo mem > /sys/power/state
1970	  bash: echo: write error: Cannot allocate memory
1971
1972	  To compile this code as a module, choose M here: the module will
1973	  be called pm-notifier-error-inject.
1974
1975	  If unsure, say N.
1976
1977config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1978	tristate "OF reconfig notifier error injection module"
1979	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1980	help
1981	  This option provides the ability to inject artificial errors to
1982	  OF reconfig notifier chain callbacks.  It is controlled
1983	  through debugfs interface under
1984	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1985
1986	  If the notifier call chain should be failed with some events
1987	  notified, write the error code to "actions/<notifier event>/error".
1988
1989	  To compile this code as a module, choose M here: the module will
1990	  be called of-reconfig-notifier-error-inject.
1991
1992	  If unsure, say N.
1993
1994config NETDEV_NOTIFIER_ERROR_INJECT
1995	tristate "Netdev notifier error injection module"
1996	depends on NET && NOTIFIER_ERROR_INJECTION
1997	help
1998	  This option provides the ability to inject artificial errors to
1999	  netdevice notifier chain callbacks.  It is controlled through debugfs
2000	  interface /sys/kernel/debug/notifier-error-inject/netdev
2001
2002	  If the notifier call chain should be failed with some events
2003	  notified, write the error code to "actions/<notifier event>/error".
2004
2005	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
2006
2007	  # cd /sys/kernel/debug/notifier-error-inject/netdev
2008	  # echo -22 > actions/NETDEV_CHANGEMTU/error
2009	  # ip link set eth0 mtu 1024
2010	  RTNETLINK answers: Invalid argument
2011
2012	  To compile this code as a module, choose M here: the module will
2013	  be called netdev-notifier-error-inject.
2014
2015	  If unsure, say N.
2016
2017config FUNCTION_ERROR_INJECTION
2018	bool "Fault-injections of functions"
2019	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
2020	help
2021	  Add fault injections into various functions that are annotated with
2022	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
2023	  value of these functions. This is useful to test error paths of code.
2024
2025	  If unsure, say N
2026
2027config FAULT_INJECTION
2028	bool "Fault-injection framework"
2029	depends on DEBUG_KERNEL
2030	help
2031	  Provide fault-injection framework.
2032	  For more details, see Documentation/fault-injection/.
2033
2034config FAILSLAB
2035	bool "Fault-injection capability for kmalloc"
2036	depends on FAULT_INJECTION
2037	help
2038	  Provide fault-injection capability for kmalloc.
2039
2040config FAIL_PAGE_ALLOC
2041	bool "Fault-injection capability for alloc_pages()"
2042	depends on FAULT_INJECTION
2043	help
2044	  Provide fault-injection capability for alloc_pages().
2045
2046config FAULT_INJECTION_USERCOPY
2047	bool "Fault injection capability for usercopy functions"
2048	depends on FAULT_INJECTION
2049	help
2050	  Provides fault-injection capability to inject failures
2051	  in usercopy functions (copy_from_user(), get_user(), ...).
2052
2053config FAIL_MAKE_REQUEST
2054	bool "Fault-injection capability for disk IO"
2055	depends on FAULT_INJECTION && BLOCK
2056	help
2057	  Provide fault-injection capability for disk IO.
2058
2059config FAIL_IO_TIMEOUT
2060	bool "Fault-injection capability for faking disk interrupts"
2061	depends on FAULT_INJECTION && BLOCK
2062	help
2063	  Provide fault-injection capability on end IO handling. This
2064	  will make the block layer "forget" an interrupt as configured,
2065	  thus exercising the error handling.
2066
2067	  Only works with drivers that use the generic timeout handling,
2068	  for others it won't do anything.
2069
2070config FAIL_FUTEX
2071	bool "Fault-injection capability for futexes"
2072	select DEBUG_FS
2073	depends on FAULT_INJECTION && FUTEX
2074	help
2075	  Provide fault-injection capability for futexes.
2076
2077config FAULT_INJECTION_DEBUG_FS
2078	bool "Debugfs entries for fault-injection capabilities"
2079	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2080	help
2081	  Enable configuration of fault-injection capabilities via debugfs.
2082
2083config FAIL_FUNCTION
2084	bool "Fault-injection capability for functions"
2085	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2086	help
2087	  Provide function-based fault-injection capability.
2088	  This will allow you to override a specific function with a return
2089	  with given return value. As a result, function caller will see
2090	  an error value and have to handle it. This is useful to test the
2091	  error handling in various subsystems.
2092
2093config FAIL_MMC_REQUEST
2094	bool "Fault-injection capability for MMC IO"
2095	depends on FAULT_INJECTION_DEBUG_FS && MMC
2096	help
2097	  Provide fault-injection capability for MMC IO.
2098	  This will make the mmc core return data errors. This is
2099	  useful to test the error handling in the mmc block device
2100	  and to test how the mmc host driver handles retries from
2101	  the block device.
2102
2103config FAIL_SUNRPC
2104	bool "Fault-injection capability for SunRPC"
2105	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2106	help
2107	  Provide fault-injection capability for SunRPC and
2108	  its consumers.
2109
2110config FAIL_SKB_REALLOC
2111	bool "Fault-injection capability forcing skb to reallocate"
2112	depends on FAULT_INJECTION_DEBUG_FS
2113	help
2114	  Provide fault-injection capability that forces the skb to be
2115	  reallocated, catching possible invalid pointers to the skb.
2116
2117	  For more information, check
2118	  Documentation/fault-injection/fault-injection.rst
2119
2120config FAULT_INJECTION_CONFIGFS
2121	bool "Configfs interface for fault-injection capabilities"
2122	depends on FAULT_INJECTION
2123	select CONFIGFS_FS
2124	help
2125	  This option allows configfs-based drivers to dynamically configure
2126	  fault-injection via configfs.  Each parameter for driver-specific
2127	  fault-injection can be made visible as a configfs attribute in a
2128	  configfs group.
2129
2130
2131config FAULT_INJECTION_STACKTRACE_FILTER
2132	bool "stacktrace filter for fault-injection capabilities"
2133	depends on FAULT_INJECTION
2134	depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
2135	select STACKTRACE
2136	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2137	help
2138	  Provide stacktrace filter for fault-injection capabilities
2139
2140config ARCH_HAS_KCOV
2141	bool
2142	help
2143	  An architecture should select this when it can successfully
2144	  build and run with CONFIG_KCOV. This typically requires
2145	  disabling instrumentation for some early boot code.
2146
2147config KCOV
2148	bool "Code coverage for fuzzing"
2149	depends on ARCH_HAS_KCOV
2150	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2151		   GCC_VERSION >= 120000 || CC_IS_CLANG
2152	select DEBUG_FS
2153	select OBJTOOL if HAVE_NOINSTR_HACK
2154	help
2155	  KCOV exposes kernel code coverage information in a form suitable
2156	  for coverage-guided fuzzing (randomized testing).
2157
2158	  For more details, see Documentation/dev-tools/kcov.rst.
2159
2160config KCOV_ENABLE_COMPARISONS
2161	bool "Enable comparison operands collection by KCOV"
2162	depends on KCOV
2163	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2164	help
2165	  KCOV also exposes operands of every comparison in the instrumented
2166	  code along with operand sizes and PCs of the comparison instructions.
2167	  These operands can be used by fuzzing engines to improve the quality
2168	  of fuzzing coverage.
2169
2170config KCOV_INSTRUMENT_ALL
2171	bool "Instrument all code by default"
2172	depends on KCOV
2173	default y
2174	help
2175	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2176	  then you will want to instrument the whole kernel and you should
2177	  say y here. If you are doing more targeted fuzzing (like e.g.
2178	  filesystem fuzzing with AFL) then you will want to enable coverage
2179	  for more specific subsets of files, and should say n here.
2180
2181config KCOV_IRQ_AREA_SIZE
2182	hex "Size of interrupt coverage collection area in words"
2183	depends on KCOV
2184	default 0x40000
2185	help
2186	  KCOV uses preallocated per-cpu areas to collect coverage from
2187	  soft interrupts. This specifies the size of those areas in the
2188	  number of unsigned long words.
2189
2190config KCOV_SELFTEST
2191	bool "Perform short selftests on boot"
2192	depends on KCOV
2193	help
2194	  Run short KCOV coverage collection selftests on boot.
2195	  On test failure, causes the kernel to panic. Recommended to be
2196	  enabled, ensuring critical functionality works as intended.
2197
2198menuconfig RUNTIME_TESTING_MENU
2199	bool "Runtime Testing"
2200	default y
2201
2202if RUNTIME_TESTING_MENU
2203
2204config TEST_DHRY
2205	tristate "Dhrystone benchmark test"
2206	help
2207	  Enable this to include the Dhrystone 2.1 benchmark.  This test
2208	  calculates the number of Dhrystones per second, and the number of
2209	  DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2210	  by 1757 (the number of Dhrystones per second obtained on the VAX
2211	  11/780, nominally a 1 MIPS machine).
2212
2213	  To run the benchmark, it needs to be enabled explicitly, either from
2214	  the kernel command line (when built-in), or from userspace (when
2215	  built-in or modular).
2216
2217	  Run once during kernel boot:
2218
2219	      test_dhry.run
2220
2221	  Set number of iterations from kernel command line:
2222
2223	      test_dhry.iterations=<n>
2224
2225	  Set number of iterations from userspace:
2226
2227	      echo <n> > /sys/module/test_dhry/parameters/iterations
2228
2229	  Trigger manual run from userspace:
2230
2231	      echo y > /sys/module/test_dhry/parameters/run
2232
2233	  If the number of iterations is <= 0, the test will devise a suitable
2234	  number of iterations (test runs for at least 2s) automatically.
2235	  This process takes ca. 4s.
2236
2237	  If unsure, say N.
2238
2239config LKDTM
2240	tristate "Linux Kernel Dump Test Tool Module"
2241	depends on DEBUG_FS
2242	help
2243	This module enables testing of the different dumping mechanisms by
2244	inducing system failures at predefined crash points.
2245	If you don't need it: say N
2246	Choose M here to compile this code as a module. The module will be
2247	called lkdtm.
2248
2249	Documentation on how to use the module can be found in
2250	Documentation/fault-injection/provoke-crashes.rst
2251
2252config CPUMASK_KUNIT_TEST
2253	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2254	depends on KUNIT
2255	default KUNIT_ALL_TESTS
2256	help
2257	  Enable to turn on cpumask tests, running at boot or module load time.
2258
2259	  For more information on KUnit and unit tests in general, please refer
2260	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2261
2262	  If unsure, say N.
2263
2264config TEST_LIST_SORT
2265	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2266	depends on KUNIT
2267	default KUNIT_ALL_TESTS
2268	help
2269	  Enable this to turn on 'list_sort()' function test. This test is
2270	  executed only once during system boot (so affects only boot time),
2271	  or at module load time.
2272
2273	  If unsure, say N.
2274
2275config TEST_MIN_HEAP
2276	tristate "Min heap test"
2277	depends on DEBUG_KERNEL || m
2278	help
2279	  Enable this to turn on min heap function tests. This test is
2280	  executed only once during system boot (so affects only boot time),
2281	  or at module load time.
2282
2283	  If unsure, say N.
2284
2285config TEST_SORT
2286	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2287	depends on KUNIT
2288	default KUNIT_ALL_TESTS
2289	help
2290	  This option enables the self-test function of 'sort()' at boot,
2291	  or at module load time.
2292
2293	  If unsure, say N.
2294
2295config TEST_DIV64
2296	tristate "64bit/32bit division and modulo test"
2297	depends on DEBUG_KERNEL || m
2298	help
2299	  Enable this to turn on 'do_div()' function test. This test is
2300	  executed only once during system boot (so affects only boot time),
2301	  or at module load time.
2302
2303	  If unsure, say N.
2304
2305config TEST_MULDIV64
2306	tristate "mul_u64_u64_div_u64() test"
2307	depends on DEBUG_KERNEL || m
2308	help
2309	  Enable this to turn on 'mul_u64_u64_div_u64()' function test.
2310	  This test is executed only once during system boot (so affects
2311	  only boot time), or at module load time.
2312
2313	  If unsure, say N.
2314
2315config TEST_IOV_ITER
2316	tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS
2317	depends on KUNIT
2318	depends on MMU
2319	default KUNIT_ALL_TESTS
2320	help
2321	  Enable this to turn on testing of the operation of the I/O iterator
2322	  (iov_iter). This test is executed only once during system boot (so
2323	  affects only boot time), or at module load time.
2324
2325	  If unsure, say N.
2326
2327config KPROBES_SANITY_TEST
2328	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2329	depends on DEBUG_KERNEL
2330	depends on KPROBES
2331	depends on KUNIT
2332	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2333	default KUNIT_ALL_TESTS
2334	help
2335	  This option provides for testing basic kprobes functionality on
2336	  boot. Samples of kprobe and kretprobe are inserted and
2337	  verified for functionality.
2338
2339	  Say N if you are unsure.
2340
2341config FPROBE_SANITY_TEST
2342	bool "Self test for fprobe"
2343	depends on DEBUG_KERNEL
2344	depends on FPROBE
2345	depends on KUNIT=y
2346	help
2347	  This option will enable testing the fprobe when the system boot.
2348	  A series of tests are made to verify that the fprobe is functioning
2349	  properly.
2350
2351	  Say N if you are unsure.
2352
2353config BACKTRACE_SELF_TEST
2354	tristate "Self test for the backtrace code"
2355	depends on DEBUG_KERNEL
2356	help
2357	  This option provides a kernel module that can be used to test
2358	  the kernel stack backtrace code. This option is not useful
2359	  for distributions or general kernels, but only for kernel
2360	  developers working on architecture code.
2361
2362	  Note that if you want to also test saved backtraces, you will
2363	  have to enable STACKTRACE as well.
2364
2365	  Say N if you are unsure.
2366
2367config TEST_REF_TRACKER
2368	tristate "Self test for reference tracker"
2369	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2370	select REF_TRACKER
2371	help
2372	  This option provides a kernel module performing tests
2373	  using reference tracker infrastructure.
2374
2375	  Say N if you are unsure.
2376
2377config RBTREE_TEST
2378	tristate "Red-Black tree test"
2379	depends on DEBUG_KERNEL
2380	help
2381	  A benchmark measuring the performance of the rbtree library.
2382	  Also includes rbtree invariant checks.
2383
2384config REED_SOLOMON_TEST
2385	tristate "Reed-Solomon library test"
2386	depends on DEBUG_KERNEL || m
2387	select REED_SOLOMON
2388	select REED_SOLOMON_ENC16
2389	select REED_SOLOMON_DEC16
2390	help
2391	  This option enables the self-test function of rslib at boot,
2392	  or at module load time.
2393
2394	  If unsure, say N.
2395
2396config INTERVAL_TREE_TEST
2397	tristate "Interval tree test"
2398	depends on DEBUG_KERNEL
2399	select INTERVAL_TREE
2400	help
2401	  A benchmark measuring the performance of the interval tree library
2402
2403config PERCPU_TEST
2404	tristate "Per cpu operations test"
2405	depends on m && DEBUG_KERNEL
2406	help
2407	  Enable this option to build test module which validates per-cpu
2408	  operations.
2409
2410	  If unsure, say N.
2411
2412config ATOMIC64_SELFTEST
2413	tristate "Perform an atomic64_t self-test"
2414	help
2415	  Enable this option to test the atomic64_t functions at boot or
2416	  at module load time.
2417
2418	  If unsure, say N.
2419
2420config ASYNC_RAID6_TEST
2421	tristate "Self test for hardware accelerated raid6 recovery"
2422	depends on ASYNC_RAID6_RECOV
2423	select ASYNC_MEMCPY
2424	help
2425	  This is a one-shot self test that permutes through the
2426	  recovery of all the possible two disk failure scenarios for a
2427	  N-disk array.  Recovery is performed with the asynchronous
2428	  raid6 recovery routines, and will optionally use an offload
2429	  engine if one is available.
2430
2431	  If unsure, say N.
2432
2433config TEST_HEXDUMP
2434	tristate "Test functions located in the hexdump module at runtime"
2435
2436config PRINTF_KUNIT_TEST
2437	tristate "KUnit test printf() family of functions at runtime" if !KUNIT_ALL_TESTS
2438	depends on KUNIT
2439	default KUNIT_ALL_TESTS
2440	help
2441	  Enable this option to test the printf functions at runtime.
2442
2443	  If unsure, say N.
2444
2445config SCANF_KUNIT_TEST
2446	tristate "KUnit test scanf() family of functions at runtime" if !KUNIT_ALL_TESTS
2447	depends on KUNIT
2448	default KUNIT_ALL_TESTS
2449	help
2450	  Enable this option to test the scanf functions at runtime.
2451
2452	  If unsure, say N.
2453
2454config SEQ_BUF_KUNIT_TEST
2455	tristate "KUnit test for seq_buf" if !KUNIT_ALL_TESTS
2456	depends on KUNIT
2457	default KUNIT_ALL_TESTS
2458	help
2459	  This builds unit tests for the seq_buf library.
2460
2461	  If unsure, say N.
2462
2463config STRING_KUNIT_TEST
2464	tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS
2465	depends on KUNIT
2466	default KUNIT_ALL_TESTS
2467
2468config STRING_HELPERS_KUNIT_TEST
2469	tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS
2470	depends on KUNIT
2471	default KUNIT_ALL_TESTS
2472
2473config FFS_KUNIT_TEST
2474	tristate "KUnit test ffs-family functions at runtime" if !KUNIT_ALL_TESTS
2475	depends on KUNIT
2476	default KUNIT_ALL_TESTS
2477	help
2478	  This builds KUnit tests for ffs-family bit manipulation functions
2479	  including ffs(), __ffs(), fls(), __fls(), fls64(), and __ffs64().
2480
2481	  These tests validate mathematical correctness, edge case handling,
2482	  and cross-architecture consistency of bit scanning functions.
2483
2484	  For more information on KUnit and unit tests in general,
2485	  please refer to Documentation/dev-tools/kunit/.
2486
2487config TEST_KSTRTOX
2488	tristate "Test kstrto*() family of functions at runtime"
2489
2490config TEST_BITMAP
2491	tristate "Test bitmap_*() family of functions at runtime"
2492	help
2493	  Enable this option to test the bitmap functions at boot.
2494
2495	  If unsure, say N.
2496
2497config TEST_UUID
2498	tristate "Test functions located in the uuid module at runtime"
2499
2500config TEST_XARRAY
2501	tristate "Test the XArray code at runtime"
2502
2503config TEST_MAPLE_TREE
2504	tristate "Test the Maple Tree code at runtime or module load"
2505	help
2506	  Enable this option to test the maple tree code functions at boot, or
2507	  when the module is loaded. Enable "Debug Maple Trees" will enable
2508	  more verbose output on failures.
2509
2510	  If unsure, say N.
2511
2512config TEST_RHASHTABLE
2513	tristate "Perform selftest on resizable hash table"
2514	help
2515	  Enable this option to test the rhashtable functions at boot.
2516
2517	  If unsure, say N.
2518
2519config TEST_IDA
2520	tristate "Perform selftest on IDA functions"
2521
2522config TEST_MISC_MINOR
2523	bool "miscdevice KUnit test" if !KUNIT_ALL_TESTS
2524	depends on KUNIT=y
2525	default KUNIT_ALL_TESTS
2526	help
2527	  Kunit test for miscdevice API, specially its behavior in respect to
2528	  static and dynamic minor numbers.
2529
2530	  KUnit tests run during boot and output the results to the debug log
2531	  in TAP format (https://testanything.org/). Only useful for kernel devs
2532	  running the KUnit test harness, and not intended for inclusion into a
2533	  production build.
2534
2535	  For more information on KUnit and unit tests in general please refer
2536	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2537
2538	  If unsure, say N.
2539
2540config TEST_PARMAN
2541	tristate "Perform selftest on priority array manager"
2542	depends on PARMAN
2543	help
2544	  Enable this option to test priority array manager on boot
2545	  (or module load).
2546
2547	  If unsure, say N.
2548
2549config TEST_IRQ_TIMINGS
2550	bool "IRQ timings selftest"
2551	depends on IRQ_TIMINGS
2552	help
2553	  Enable this option to test the irq timings code on boot.
2554
2555	  If unsure, say N.
2556
2557config TEST_LKM
2558	tristate "Test module loading with 'hello world' module"
2559	depends on m
2560	help
2561	  This builds the "test_module" module that emits "Hello, world"
2562	  on printk when loaded. It is designed to be used for basic
2563	  evaluation of the module loading subsystem (for example when
2564	  validating module verification). It lacks any extra dependencies,
2565	  and will not normally be loaded by the system unless explicitly
2566	  requested by name.
2567
2568	  If unsure, say N.
2569
2570config TEST_BITOPS
2571	tristate "Test module for compilation of bitops operations"
2572	help
2573	  This builds the "test_bitops" module that is much like the
2574	  TEST_LKM module except that it does a basic exercise of the
2575	  set/clear_bit macros and get_count_order/long to make sure there are
2576	  no compiler warnings from C=1 sparse checker or -Wextra
2577	  compilations. It has no dependencies and doesn't run or load unless
2578	  explicitly requested by name.  for example: modprobe test_bitops.
2579
2580	  If unsure, say N.
2581
2582config TEST_VMALLOC
2583	tristate "Test module for stress/performance analysis of vmalloc allocator"
2584	default n
2585	depends on MMU
2586	help
2587	  This builds the "test_vmalloc" module that should be used for
2588	  stress and performance analysis. So, any new change for vmalloc
2589	  subsystem can be evaluated from performance and stability point
2590	  of view.
2591
2592	  If unsure, say N.
2593
2594config TEST_BPF
2595	tristate "Test BPF filter functionality"
2596	depends on m && NET
2597	help
2598	  This builds the "test_bpf" module that runs various test vectors
2599	  against the BPF interpreter or BPF JIT compiler depending on the
2600	  current setting. This is in particular useful for BPF JIT compiler
2601	  development, but also to run regression tests against changes in
2602	  the interpreter code. It also enables test stubs for eBPF maps and
2603	  verifier used by user space verifier testsuite.
2604
2605	  If unsure, say N.
2606
2607config FIND_BIT_BENCHMARK
2608	tristate "Test find_bit functions"
2609	help
2610	  This builds the "test_find_bit" module that measure find_*_bit()
2611	  functions performance.
2612
2613	  If unsure, say N.
2614
2615config FIND_BIT_BENCHMARK_RUST
2616	tristate "Test find_bit functions in Rust"
2617	depends on RUST
2618	help
2619	  This builds the "find_bit_benchmark_rust" module. It is a micro
2620          benchmark that measures the performance of Rust functions that
2621          correspond to the find_*_bit() operations in C. It follows the
2622          FIND_BIT_BENCHMARK closely but will in general not yield same
2623          numbers due to extra bounds checks and overhead of foreign
2624          function calls.
2625
2626	  If unsure, say N.
2627
2628config TEST_FIRMWARE
2629	tristate "Test firmware loading via userspace interface"
2630	depends on FW_LOADER
2631	help
2632	  This builds the "test_firmware" module that creates a userspace
2633	  interface for testing firmware loading. This can be used to
2634	  control the triggering of firmware loading without needing an
2635	  actual firmware-using device. The contents can be rechecked by
2636	  userspace.
2637
2638	  If unsure, say N.
2639
2640config TEST_SYSCTL
2641	tristate "sysctl test driver"
2642	depends on PROC_SYSCTL
2643	help
2644	  This builds the "test_sysctl" module. This driver enables to test the
2645	  proc sysctl interfaces available to drivers safely without affecting
2646	  production knobs which might alter system functionality.
2647
2648	  If unsure, say N.
2649
2650config BITOPS_KUNIT
2651	tristate "KUnit test for bitops" if !KUNIT_ALL_TESTS
2652	depends on KUNIT
2653	default KUNIT_ALL_TESTS
2654	help
2655	  This option enables the KUnit test for the bitops library
2656	  which provides functions for bit operations.
2657
2658	  Note that this is derived from the original test_bitops module.
2659	  For micro-benchmarks and compiler warning checks, enable TEST_BITOPS.
2660
2661	  If unsure, say N.
2662
2663config BITFIELD_KUNIT
2664	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2665	depends on KUNIT
2666	default KUNIT_ALL_TESTS
2667	help
2668	  Enable this option to test the bitfield functions at boot.
2669
2670	  KUnit tests run during boot and output the results to the debug log
2671	  in TAP format (http://testanything.org/). Only useful for kernel devs
2672	  running the KUnit test harness, and not intended for inclusion into a
2673	  production build.
2674
2675	  For more information on KUnit and unit tests in general please refer
2676	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2677
2678	  If unsure, say N.
2679
2680config CHECKSUM_KUNIT
2681	tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2682	depends on KUNIT
2683	default KUNIT_ALL_TESTS
2684	help
2685	  Enable this option to test the checksum functions at boot.
2686
2687	  KUnit tests run during boot and output the results to the debug log
2688	  in TAP format (http://testanything.org/). Only useful for kernel devs
2689	  running the KUnit test harness, and not intended for inclusion into a
2690	  production build.
2691
2692	  For more information on KUnit and unit tests in general please refer
2693	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2694
2695	  If unsure, say N.
2696
2697config UTIL_MACROS_KUNIT
2698	tristate "KUnit test util_macros.h functions at runtime" if !KUNIT_ALL_TESTS
2699	depends on KUNIT
2700	default KUNIT_ALL_TESTS
2701	help
2702	  Enable this option to test the util_macros.h function at boot.
2703
2704	  KUnit tests run during boot and output the results to the debug log
2705	  in TAP format (http://testanything.org/). Only useful for kernel devs
2706	  running the KUnit test harness, and not intended for inclusion into a
2707	  production build.
2708
2709	  For more information on KUnit and unit tests in general please refer
2710	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2711
2712	  If unsure, say N.
2713
2714config HASH_KUNIT_TEST
2715	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2716	depends on KUNIT
2717	default KUNIT_ALL_TESTS
2718	help
2719	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2720	  integer (<linux/hash.h>) hash functions on boot.
2721
2722	  KUnit tests run during boot and output the results to the debug log
2723	  in TAP format (https://testanything.org/). Only useful for kernel devs
2724	  running the KUnit test harness, and not intended for inclusion into a
2725	  production build.
2726
2727	  For more information on KUnit and unit tests in general please refer
2728	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2729
2730	  This is intended to help people writing architecture-specific
2731	  optimized versions. If unsure, say N.
2732
2733config RESOURCE_KUNIT_TEST
2734	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2735	depends on KUNIT
2736	default KUNIT_ALL_TESTS
2737	select GET_FREE_REGION
2738	help
2739	  This builds the resource API unit test.
2740	  Tests the logic of API provided by resource.c and ioport.h.
2741	  For more information on KUnit and unit tests in general please refer
2742	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2743
2744	  If unsure, say N.
2745
2746config SYSCTL_KUNIT_TEST
2747	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2748	depends on KUNIT
2749	default KUNIT_ALL_TESTS
2750	help
2751	  This builds the proc sysctl unit test, which runs on boot.
2752	  Tests the API contract and implementation correctness of sysctl.
2753	  For more information on KUnit and unit tests in general please refer
2754	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2755
2756	  If unsure, say N.
2757
2758config KFIFO_KUNIT_TEST
2759	tristate "KUnit Test for the generic kernel FIFO implementation" if !KUNIT_ALL_TESTS
2760	depends on KUNIT
2761	default KUNIT_ALL_TESTS
2762	help
2763	  This builds the generic FIFO implementation KUnit test suite.
2764	  It tests that the API and basic functionality of the kfifo type
2765	  and associated macros.
2766
2767	  For more information on KUnit and unit tests in general please refer
2768	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2769
2770	  If unsure, say N.
2771
2772config LIST_KUNIT_TEST
2773	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2774	depends on KUNIT
2775	default KUNIT_ALL_TESTS
2776	help
2777	  This builds the linked list KUnit test suite.
2778	  It tests that the API and basic functionality of the list_head type
2779	  and associated macros.
2780
2781	  KUnit tests run during boot and output the results to the debug log
2782	  in TAP format (https://testanything.org/). Only useful for kernel devs
2783	  running the KUnit test harness, and not intended for inclusion into a
2784	  production build.
2785
2786	  For more information on KUnit and unit tests in general please refer
2787	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2788
2789	  If unsure, say N.
2790
2791config HASHTABLE_KUNIT_TEST
2792	tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2793	depends on KUNIT
2794	default KUNIT_ALL_TESTS
2795	help
2796	  This builds the hashtable KUnit test suite.
2797	  It tests the basic functionality of the API defined in
2798	  include/linux/hashtable.h. For more information on KUnit and
2799	  unit tests in general please refer to the KUnit documentation
2800	  in Documentation/dev-tools/kunit/.
2801
2802	  If unsure, say N.
2803
2804config LINEAR_RANGES_TEST
2805	tristate "KUnit test for linear_ranges"
2806	depends on KUNIT
2807	select LINEAR_RANGES
2808	help
2809	  This builds the linear_ranges unit test, which runs on boot.
2810	  Tests the linear_ranges logic correctness.
2811	  For more information on KUnit and unit tests in general please refer
2812	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2813
2814	  If unsure, say N.
2815
2816config CMDLINE_KUNIT_TEST
2817	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2818	depends on KUNIT
2819	default KUNIT_ALL_TESTS
2820	help
2821	  This builds the cmdline API unit test.
2822	  Tests the logic of API provided by cmdline.c.
2823	  For more information on KUnit and unit tests in general please refer
2824	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2825
2826	  If unsure, say N.
2827
2828config BASE64_KUNIT
2829	tristate "KUnit test for base64 decoding and encoding" if !KUNIT_ALL_TESTS
2830	depends on KUNIT
2831	default KUNIT_ALL_TESTS
2832	help
2833	  This builds the base64 unit tests.
2834
2835	  The tests cover the encoding and decoding logic of Base64 functions
2836	  in the kernel.
2837	  In addition to correctness checks, simple performance benchmarks
2838	  for both encoding and decoding are also included.
2839
2840	  For more information on KUnit and unit tests in general please refer
2841	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2842
2843	  If unsure, say N.
2844
2845config BITS_TEST
2846	tristate "KUnit test for bit functions and macros" if !KUNIT_ALL_TESTS
2847	depends on KUNIT
2848	default KUNIT_ALL_TESTS
2849	help
2850	  This builds the bits unit test.
2851	  Tests the logic of macros defined in bits.h.
2852	  For more information on KUnit and unit tests in general please refer
2853	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2854
2855	  If unsure, say N.
2856
2857config SLUB_KUNIT_TEST
2858	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2859	depends on SLUB_DEBUG && KUNIT
2860	default KUNIT_ALL_TESTS
2861	help
2862	  This builds SLUB allocator unit test.
2863	  Tests SLUB cache debugging functionality.
2864	  For more information on KUnit and unit tests in general please refer
2865	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2866
2867	  If unsure, say N.
2868
2869config RATIONAL_KUNIT_TEST
2870	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2871	depends on KUNIT && RATIONAL
2872	default KUNIT_ALL_TESTS
2873	help
2874	  This builds the rational math unit test.
2875	  For more information on KUnit and unit tests in general please refer
2876	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2877
2878	  If unsure, say N.
2879
2880config MEMCPY_KUNIT_TEST
2881	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2882	depends on KUNIT
2883	default KUNIT_ALL_TESTS
2884	help
2885	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2886	  For more information on KUnit and unit tests in general please refer
2887	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2888
2889	  If unsure, say N.
2890
2891config IS_SIGNED_TYPE_KUNIT_TEST
2892	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2893	depends on KUNIT
2894	default KUNIT_ALL_TESTS
2895	help
2896	  Builds unit tests for the is_signed_type() macro.
2897
2898	  For more information on KUnit and unit tests in general please refer
2899	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2900
2901	  If unsure, say N.
2902
2903config OVERFLOW_KUNIT_TEST
2904	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2905	depends on KUNIT
2906	default KUNIT_ALL_TESTS
2907	help
2908	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2909	  related functions.
2910
2911	  For more information on KUnit and unit tests in general please refer
2912	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2913
2914	  If unsure, say N.
2915
2916config RANDSTRUCT_KUNIT_TEST
2917	tristate "Test randstruct structure layout randomization at runtime" if !KUNIT_ALL_TESTS
2918	depends on KUNIT
2919	default KUNIT_ALL_TESTS
2920	help
2921	  Builds unit tests for the checking CONFIG_RANDSTRUCT=y, which
2922	  randomizes structure layouts.
2923
2924config STACKINIT_KUNIT_TEST
2925	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2926	depends on KUNIT
2927	default KUNIT_ALL_TESTS
2928	help
2929	  Test if the kernel is zero-initializing stack variables and
2930	  padding. Coverage is controlled by compiler flags,
2931	  CONFIG_INIT_STACK_ALL_PATTERN or CONFIG_INIT_STACK_ALL_ZERO.
2932
2933config FORTIFY_KUNIT_TEST
2934	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2935	depends on KUNIT
2936	default KUNIT_ALL_TESTS
2937	help
2938	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2939	  by the str*() and mem*() family of functions. For testing runtime
2940	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2941
2942config LONGEST_SYM_KUNIT_TEST
2943	tristate "Test the longest symbol possible" if !KUNIT_ALL_TESTS
2944	depends on KUNIT && KPROBES
2945	depends on !PREFIX_SYMBOLS && !CFI && !GCOV_KERNEL
2946	default KUNIT_ALL_TESTS
2947	help
2948	  Tests the longest symbol possible
2949
2950	  If unsure, say N.
2951
2952config HW_BREAKPOINT_KUNIT_TEST
2953	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2954	depends on HAVE_HW_BREAKPOINT
2955	depends on KUNIT=y
2956	default KUNIT_ALL_TESTS
2957	help
2958	  Tests for hw_breakpoint constraints accounting.
2959
2960	  If unsure, say N.
2961
2962config SIPHASH_KUNIT_TEST
2963	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2964	depends on KUNIT
2965	default KUNIT_ALL_TESTS
2966	help
2967	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2968	  functions on boot (or module load).
2969
2970	  This is intended to help people writing architecture-specific
2971	  optimized versions.  If unsure, say N.
2972
2973config USERCOPY_KUNIT_TEST
2974	tristate "KUnit Test for user/kernel boundary protections"
2975	depends on KUNIT
2976	default KUNIT_ALL_TESTS
2977	help
2978	  This builds the "usercopy_kunit" module that runs sanity checks
2979	  on the copy_to/from_user infrastructure, making sure basic
2980	  user/kernel boundary testing is working.
2981
2982config BLACKHOLE_DEV_KUNIT_TEST
2983	tristate "Test blackhole netdev functionality" if !KUNIT_ALL_TESTS
2984	depends on NET
2985	depends on KUNIT
2986	default KUNIT_ALL_TESTS
2987	help
2988	  This builds the "blackhole_dev_kunit" module that validates the
2989	  data path through this blackhole netdev.
2990
2991	  If unsure, say N.
2992
2993config TEST_UDELAY
2994	tristate "udelay test driver"
2995	help
2996	  This builds the "udelay_test" module that helps to make sure
2997	  that udelay() is working properly.
2998
2999	  If unsure, say N.
3000
3001config TEST_STATIC_KEYS
3002	tristate "Test static keys"
3003	depends on m
3004	help
3005	  Test the static key interfaces.
3006
3007	  If unsure, say N.
3008
3009config TEST_DYNAMIC_DEBUG
3010	tristate "Test DYNAMIC_DEBUG"
3011	depends on DYNAMIC_DEBUG
3012	help
3013	  This module registers a tracer callback to count enabled
3014	  pr_debugs in a 'do_debugging' function, then alters their
3015	  enablements, calls the function, and compares counts.
3016
3017	  If unsure, say N.
3018
3019config TEST_KMOD
3020	tristate "kmod stress tester"
3021	depends on m
3022	select TEST_LKM
3023	help
3024	  Test the kernel's module loading mechanism: kmod. kmod implements
3025	  support to load modules using the Linux kernel's usermode helper.
3026	  This test provides a series of tests against kmod.
3027
3028	  Although technically you can either build test_kmod as a module or
3029	  into the kernel we disallow building it into the kernel since
3030	  it stress tests request_module() and this will very likely cause
3031	  some issues by taking over precious threads available from other
3032	  module load requests, ultimately this could be fatal.
3033
3034	  To run tests run:
3035
3036	  tools/testing/selftests/kmod/kmod.sh --help
3037
3038	  If unsure, say N.
3039
3040config TEST_RUNTIME
3041	bool
3042
3043config TEST_RUNTIME_MODULE
3044	bool
3045
3046config TEST_KALLSYMS
3047	tristate "module kallsyms find_symbol() test"
3048	depends on m
3049	select TEST_RUNTIME
3050	select TEST_RUNTIME_MODULE
3051	select TEST_KALLSYMS_A
3052	select TEST_KALLSYMS_B
3053	select TEST_KALLSYMS_C
3054	select TEST_KALLSYMS_D
3055	help
3056	  This allows us to stress test find_symbol() through the kallsyms
3057	  used to place symbols on the kernel ELF kallsyms and modules kallsyms
3058	  where we place kernel symbols such as exported symbols.
3059
3060	  We have four test modules:
3061
3062	  A: has KALLSYSMS_NUMSYMS exported symbols
3063	  B: uses one of A's symbols
3064	  C: adds KALLSYMS_SCALE_FACTOR * KALLSYSMS_NUMSYMS exported
3065	  D: adds 2 * the symbols than C
3066
3067	  We stress test find_symbol() through two means:
3068
3069	  1) Upon load of B it will trigger simplify_symbols() to look for the
3070	  one symbol it uses from the module A with tons of symbols. This is an
3071	  indirect way for us to have B call resolve_symbol_wait() upon module
3072	  load. This will eventually call find_symbol() which will eventually
3073	  try to find the symbols used with find_exported_symbol_in_section().
3074	  find_exported_symbol_in_section() uses bsearch() so a binary search
3075	  for each symbol. Binary search will at worst be O(log(n)) so the
3076	  larger TEST_MODULE_KALLSYSMS the worse the search.
3077
3078	  2) The selftests should load C first, before B. Upon B's load towards
3079	  the end right before we call module B's init routine we get
3080	  complete_formation() called on the module. That will first check
3081	  for duplicate symbols with the call to verify_exported_symbols().
3082	  That is when we'll force iteration on module C's insane symbol list.
3083	  Since it has 10 * KALLSYMS_NUMSYMS it means we can first test
3084	  just loading B without C. The amount of time it takes to load C Vs
3085	  B can give us an idea of the impact growth of the symbol space and
3086	  give us projection. Module A only uses one symbol from B so to allow
3087	  this scaling in module C to be proportional, if it used more symbols
3088	  then the first test would be doing more and increasing just the
3089	  search space would be slightly different. The last module, module D
3090	  will just increase the search space by twice the number of symbols in
3091	  C so to allow for full projects.
3092
3093	  tools/testing/selftests/module/find_symbol.sh
3094
3095	  The current defaults will incur a build delay of about 7 minutes
3096	  on an x86_64 with only 8 cores. Enable this only if you want to
3097	  stress test find_symbol() with thousands of symbols. At the same
3098	  time this is also useful to test building modules with thousands of
3099	  symbols, and if BTF is enabled this also stress tests adding BTF
3100	  information for each module. Currently enabling many more symbols
3101	  will segfault the build system.
3102
3103	  If unsure, say N.
3104
3105if TEST_KALLSYMS
3106
3107config TEST_KALLSYMS_A
3108	tristate
3109	depends on m
3110
3111config TEST_KALLSYMS_B
3112	tristate
3113	depends on m
3114
3115config TEST_KALLSYMS_C
3116	tristate
3117	depends on m
3118
3119config TEST_KALLSYMS_D
3120	tristate
3121	depends on m
3122
3123choice
3124	prompt "Kallsym test range"
3125	default TEST_KALLSYMS_LARGE
3126	help
3127	  Selecting something other than "Fast" will enable tests which slow
3128	  down the build and may crash your build.
3129
3130config TEST_KALLSYMS_FAST
3131	bool "Fast builds"
3132	help
3133	  You won't really be testing kallsysms, so this just helps fast builds
3134	  when allmodconfig is used..
3135
3136config TEST_KALLSYMS_LARGE
3137	bool "Enable testing kallsyms with large exports"
3138	help
3139	  This will enable larger number of symbols. This will slow down
3140	  your build considerably.
3141
3142config TEST_KALLSYMS_MAX
3143	bool "Known kallsysms limits"
3144	help
3145	  This will enable exports to the point we know we'll start crashing
3146	  builds.
3147
3148endchoice
3149
3150config TEST_KALLSYMS_NUMSYMS
3151	int "test kallsyms number of symbols"
3152	range 2 10000
3153	default 2 if TEST_KALLSYMS_FAST
3154	default 100 if TEST_KALLSYMS_LARGE
3155	default 10000 if TEST_KALLSYMS_MAX
3156	help
3157	  The number of symbols to create on TEST_KALLSYMS_A, only one of which
3158	  module TEST_KALLSYMS_B will use. This also will be used
3159	  for how many symbols TEST_KALLSYMS_C will have, scaled up by
3160	  TEST_KALLSYMS_SCALE_FACTOR. Note that setting this to 10,000 will
3161	  trigger a segfault today, don't use anything close to it unless
3162	  you are aware that this should not be used for automated build tests.
3163
3164config TEST_KALLSYMS_SCALE_FACTOR
3165	int "test kallsyms scale factor"
3166	default 8
3167	help
3168	  How many more unusued symbols will TEST_KALLSYSMS_C have than
3169	  TEST_KALLSYMS_A. If 8, then module C will have 8 * syms
3170	  than module A. Then TEST_KALLSYMS_D will have double the amount
3171	  of symbols than C so to allow projections.
3172
3173endif # TEST_KALLSYMS
3174
3175config TEST_DEBUG_VIRTUAL
3176	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
3177	depends on DEBUG_VIRTUAL
3178	help
3179	  Test the kernel's ability to detect incorrect calls to
3180	  virt_to_phys() done against the non-linear part of the
3181	  kernel's virtual address map.
3182
3183	  If unsure, say N.
3184
3185config TEST_MEMCAT_P
3186	tristate "Test memcat_p() helper function"
3187	help
3188	  Test the memcat_p() helper for correctly merging two
3189	  pointer arrays together.
3190
3191	  If unsure, say N.
3192
3193config TEST_OBJAGG
3194	tristate "Perform selftest on object aggreration manager"
3195	default n
3196	depends on OBJAGG
3197	help
3198	  Enable this option to test object aggregation manager on boot
3199	  (or module load).
3200
3201config TEST_MEMINIT
3202	tristate "Test heap/page initialization"
3203	help
3204	  Test if the kernel is zero-initializing heap and page allocations.
3205	  This can be useful to test init_on_alloc and init_on_free features.
3206
3207	  If unsure, say N.
3208
3209config TEST_HMM
3210	tristate "Test HMM (Heterogeneous Memory Management)"
3211	depends on TRANSPARENT_HUGEPAGE
3212	depends on DEVICE_PRIVATE
3213	select HMM_MIRROR
3214	select MMU_NOTIFIER
3215	help
3216	  This is a pseudo device driver solely for testing HMM.
3217	  Say M here if you want to build the HMM test module.
3218	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
3219
3220	  If unsure, say N.
3221
3222config TEST_FREE_PAGES
3223	tristate "Test freeing pages"
3224	help
3225	  Test that a memory leak does not occur due to a race between
3226	  freeing a block of pages and a speculative page reference.
3227	  Loading this module is safe if your kernel has the bug fixed.
3228	  If the bug is not fixed, it will leak gigabytes of memory and
3229	  probably OOM your system.
3230
3231config TEST_FPU
3232	tristate "Test floating point operations in kernel space"
3233	depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL
3234	help
3235	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
3236	  which will trigger a sequence of floating point operations. This is used
3237	  for self-testing floating point control register setting in
3238	  kernel_fpu_begin().
3239
3240	  If unsure, say N.
3241
3242config TEST_CLOCKSOURCE_WATCHDOG
3243	tristate "Test clocksource watchdog in kernel space"
3244	depends on CLOCKSOURCE_WATCHDOG
3245	help
3246	  Enable this option to create a kernel module that will trigger
3247	  a test of the clocksource watchdog.  This module may be loaded
3248	  via modprobe or insmod in which case it will run upon being
3249	  loaded, or it may be built in, in which case it will run
3250	  shortly after boot.
3251
3252	  If unsure, say N.
3253
3254config TEST_OBJPOOL
3255	tristate "Test module for correctness and stress of objpool"
3256	default n
3257	depends on m && DEBUG_KERNEL
3258	help
3259	  This builds the "test_objpool" module that should be used for
3260	  correctness verification and concurrent testings of objects
3261	  allocation and reclamation.
3262
3263	  If unsure, say N.
3264
3265config TEST_KEXEC_HANDOVER
3266	bool "Test for Kexec HandOver"
3267	default n
3268	depends on KEXEC_HANDOVER
3269	help
3270	  This option enables test for Kexec HandOver (KHO).
3271	  The test consists of two parts: saving kernel data before kexec and
3272	  restoring the data after kexec and verifying that it was properly
3273	  handed over. This test module creates and saves data on the boot of
3274	  the first kernel and restores and verifies the data on the boot of
3275	  kexec'ed kernel.
3276
3277	  For detailed documentation about KHO, see Documentation/core-api/kho.
3278
3279	  To run the test run:
3280
3281	  tools/testing/selftests/kho/vmtest.sh -h
3282
3283	  If unsure, say N.
3284
3285config RATELIMIT_KUNIT_TEST
3286	tristate "KUnit Test for correctness and stress of ratelimit" if !KUNIT_ALL_TESTS
3287	depends on KUNIT
3288	default KUNIT_ALL_TESTS
3289	help
3290	  This builds the "test_ratelimit" module that should be used
3291	  for correctness verification and concurrent testings of rate
3292	  limiting.
3293
3294	  If unsure, say N.
3295
3296config INT_POW_KUNIT_TEST
3297	tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS
3298	depends on KUNIT
3299	default KUNIT_ALL_TESTS
3300	help
3301	  This option enables the KUnit test suite for the int_pow function,
3302	  which performs integer exponentiation. The test suite is designed to
3303	  verify that the implementation of int_pow correctly computes the power
3304	  of a given base raised to a given exponent.
3305
3306	  Enabling this option will include tests that check various scenarios
3307	  and edge cases to ensure the accuracy and reliability of the exponentiation
3308	  function.
3309
3310	  If unsure, say N
3311
3312config INT_SQRT_KUNIT_TEST
3313	tristate "Integer square root test" if !KUNIT_ALL_TESTS
3314	depends on KUNIT
3315	default KUNIT_ALL_TESTS
3316	help
3317	  This option enables the KUnit test suite for the int_sqrt() function,
3318	  which performs square root calculation. The test suite checks
3319	  various scenarios, including edge cases, to ensure correctness.
3320
3321	  Enabling this option will include tests that check various scenarios
3322	  and edge cases to ensure the accuracy and reliability of the square root
3323	  function.
3324
3325	  If unsure, say N
3326
3327config INT_LOG_KUNIT_TEST
3328        tristate "Integer log (int_log) test" if !KUNIT_ALL_TESTS
3329        depends on KUNIT
3330        default KUNIT_ALL_TESTS
3331        help
3332          This option enables the KUnit test suite for the int_log library, which
3333          provides two functions to compute the integer logarithm in base 2 and
3334          base 10, called respectively as intlog2 and intlog10.
3335
3336          If unsure, say N
3337
3338config GCD_KUNIT_TEST
3339	tristate "Greatest common divisor test" if !KUNIT_ALL_TESTS
3340	depends on KUNIT
3341	default KUNIT_ALL_TESTS
3342	help
3343	  This option enables the KUnit test suite for the gcd() function,
3344	  which computes the greatest common divisor of two numbers.
3345
3346	  This test suite verifies the correctness of gcd() across various
3347	  scenarios, including edge cases.
3348
3349	  If unsure, say N
3350
3351config PRIME_NUMBERS_KUNIT_TEST
3352	tristate "Prime number generator test" if !KUNIT_ALL_TESTS
3353	depends on KUNIT
3354	depends on PRIME_NUMBERS
3355	default KUNIT_ALL_TESTS
3356	help
3357	  This option enables the KUnit test suite for the {is,next}_prime_number
3358	  functions.
3359
3360	  Enabling this option will include tests that compare the prime number
3361	  generator functions against a brute force implementation.
3362
3363	  If unsure, say N
3364
3365endif # RUNTIME_TESTING_MENU
3366
3367config ARCH_USE_MEMTEST
3368	bool
3369	help
3370	  An architecture should select this when it uses early_memtest()
3371	  during boot process.
3372
3373config MEMTEST
3374	bool "Memtest"
3375	depends on ARCH_USE_MEMTEST
3376	help
3377	  This option adds a kernel parameter 'memtest', which allows memtest
3378	  to be set and executed.
3379	        memtest=0, mean disabled; -- default
3380	        memtest=1, mean do 1 test pattern;
3381	        ...
3382	        memtest=17, mean do 17 test patterns.
3383	  If you are unsure how to answer this question, answer N.
3384
3385
3386
3387config HYPERV_TESTING
3388	bool "Microsoft Hyper-V driver testing"
3389	default n
3390	depends on HYPERV && DEBUG_FS
3391	help
3392	  Select this option to enable Hyper-V vmbus testing.
3393
3394endmenu # "Kernel Testing and Coverage"
3395
3396menu "Rust hacking"
3397
3398config RUST_DEBUG_ASSERTIONS
3399	bool "Debug assertions"
3400	depends on RUST
3401	help
3402	  Enables rustc's `-Cdebug-assertions` codegen option.
3403
3404	  This flag lets you turn `cfg(debug_assertions)` conditional
3405	  compilation on or off. This can be used to enable extra debugging
3406	  code in development but not in production. For example, it controls
3407	  the behavior of the standard library's `debug_assert!` macro.
3408
3409	  Note that this will apply to all Rust code, including `core`.
3410
3411	  If unsure, say N.
3412
3413config RUST_OVERFLOW_CHECKS
3414	bool "Overflow checks"
3415	default y
3416	depends on RUST
3417	help
3418	  Enables rustc's `-Coverflow-checks` codegen option.
3419
3420	  This flag allows you to control the behavior of runtime integer
3421	  overflow. When overflow-checks are enabled, a Rust panic will occur
3422	  on overflow.
3423
3424	  Note that this will apply to all Rust code, including `core`.
3425
3426	  If unsure, say Y.
3427
3428config RUST_BUILD_ASSERT_ALLOW
3429	bool "Allow unoptimized build-time assertions"
3430	depends on RUST
3431	help
3432	  Controls how `build_error!` and `build_assert!` are handled during the build.
3433
3434	  If calls to them exist in the binary, it may indicate a violated invariant
3435	  or that the optimizer failed to verify the invariant during compilation.
3436
3437	  This should not happen, thus by default the build is aborted. However,
3438	  as an escape hatch, you can choose Y here to ignore them during build
3439	  and let the check be carried at runtime (with `panic!` being called if
3440	  the check fails).
3441
3442	  If unsure, say N.
3443
3444config RUST_KERNEL_DOCTESTS
3445	bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
3446	depends on RUST && KUNIT=y
3447	default KUNIT_ALL_TESTS
3448	help
3449	  This builds the documentation tests of the `kernel` crate
3450	  as KUnit tests.
3451
3452	  For more information on KUnit and unit tests in general,
3453	  please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
3454
3455	  If unsure, say N.
3456
3457endmenu # "Rust"
3458
3459endmenu # Kernel hacking
3460